Show Area Forecast Discussion - Charleston, SC (Charleston, SC Area) Selection: |
#1173153 (Received by flhurricane at: 7:30 PM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 721 PM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area tonight and prevail into Thursday. A storm system could impact the area Friday and Saturday, before high pressure returns early next week. && .NEAR TERM /THROUGH TUESDAY/... Tonight: A short-wave trough will be swinging through the Carolinas and Mid Atlantic region during the course of the evening and off the coast overnight. Strongest larger scale forcing for ascent will be well to our north, although with so much dry air there won`t be any rainfall across our region. The main issue for us will be a period of gustier winds and decent cold advection as a large of high pressure (across the central CONUS today) expands into the Gulf Coast and southeast CONUS in the wake of the trough. Tightening pressure gradient (4-5 millibars across the CWA later this evening into the overnight) will lead to a period of gustier winds during that time with gusts of 25 to 30 mph anticipated across the region. As a result, a Lake Wind Advisory is in effect for Lake Moultrie. Winds will be tapering off some through the overnight hours as cold advection slows down. Temperature-wise: Strong cold advection drives the 850 mb temps down into the -2C to -4C range by morning. This is far below normal, which should be around 8.5C to 8.7C. Along with diminishing winds and clearing skies, lows will drop through the 30s for all areas away from the coast with the coldest readings well inland. Persistent winds and dry incoming air mass will limit frost development to no more than maybe a little patchy coverage late near the US-301 corridor. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Aloft, a large trough will pivot offshore Tuesday, shifting further away from the region while a zonal flow takes place across the Southeast United States through mid-week. At the sfc, high pressure across the South-central United States will extend east across Gulf Coast states and Carolinas Tuesday into Wednesday, before a cold front arrives from the north/northwest by early Thursday. Conditions will remain dry locally through the middle of the week while a west-northwest downslope wind prevails along the eastern edge of the high centered to our west, even as the cold front pushes into the local area by early Thursday. Despite ample sfc heating under clear skies, temps will struggle to warm significantly on Tuesday while weak cold air advection wanes across the region. In general, high temps should only peak in the upper 50s to lower 60s (warmest across southeast Georgia). Although temps are cooler during peak heating, dry air should lead to afternoon RH values between 20- 25% away from the coast Tuesday afternoon. Sfc winds are expected to remain below 10 mph though, so fire wx concerns should be limited. Sfc winds should slowly turn southwest Tuesday night into Wednesday, offsetting some radiational cooling at night and resulting in airmass modification on Wednesday ahead of an arriving cold front. In general, Tuesday night lows should dip into the upper 30s/lower 40s inland to mid-upper 40s near the coast. On Wednesday, high temps should peak in the lower 70s with sunny conditions in place. Guidance indicates a dry cold front pushing across the region Wednesday night, likely becoming positioned along or just south of the local area by daybreak Thursday. Despite northerly winds post fropa, sfc temps should peak in the lower 70s under partly sunny skies in advance of a low pressure system developing and shifting eastward across the northern Gulf of Mexico heading into late week. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The weather becomes more active as we head into late week, although still some forecast details to hash out. An upper wave is expected to pass across the Southeast United States early Friday through early Saturday, forcing an area of low pressure across the northeast Gulf to possibly strengthen while tracking over/near the Georgia and South Carolina coasts. PWATs should increase to around 1.25 inches as the system nears, and with strong isentropic ascent and a lingering front across the area, should promote showers to develop locally Thursday night into Friday morning. Scattered to numerous showers are now forecast to occur for most areas Friday and Friday evening, before precip activity trends offshore with the sfc low pulling away Saturday. Some guidance suggests some modest instability developing near the coast and offshore as the low tracks near the region, so a few embedded thunderstorms are possible along the immediate coast. The aforementioned low should continue to depart the region late weekend as high pressure builds inland. Aside from some lingering showers Saturday morning into early afternoon, precip chances should become confined to the coastal waters by Saturday evening. Dry conditions should then prevail Sunday with high pressure in place. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR conditions anticipated through 00Z Wednesday. Gusty NW winds peaking around 25 kt or so much of tonight, will diminish to around 10 kt by 08-10Z Tuesday, as cold advection diminishes and the gradient slackens some. Extended Aviation Outlook: VFR conditions are expected Tuesday night through Thursday. Flight restrictions are possible at KCHS/KJZI/KSAV terminals Thursday night into Friday as showers/low clouds develop with a passing low pressure system. && .MARINE... Strong high pressure building into the region tonight will lead to a period of gusty northwesterly winds later this evening into the overnight hours. Gale force gusts are anticipated in all coastal waters outside of Charleston Harbor...Small Craft Advisory conditions in the Harbor. Seas will build this evening and peak during the early overnight hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions will improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston County waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is then expected to pass near/off the Southeast Coast Friday into Saturday, likely contributing to deteriorating marine conditions across local waters this weekend. Small Craft Advisories should be needed across most waters, but the track/strength of the low pressure system will play a large role in overall impacts along the Southeast Coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory until 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory until 6 AM EDT Tuesday for AMZ330. Gale Warning until 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173150 (Received by flhurricane at: 7:17 PM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 705 PM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area tonight and prevail into Thursday. A storm system could impact the area Friday and Saturday, before high pressure returns early next week. && .NEAR TERM /THROUGH TUESDAY/... Tonight: A short-wave trough will be swinging through the Carolinas and Mid Atlantic region during the course of the evening and off the coast overnight. Strongest larger scale forcing for ascent will be well to our north, although with so much dry air there won`t be any rainfall across our region. The main issue for us will be a period of gustier winds and decent cold advection as a large of high pressure (across the central CONUS today) expands into the Gulf Coast and southeast CONUS in the wake of the trough. Tightening pressure gradient (4-5 millibars across the CWA later this evening into the overnight) will lead to a period of gustier winds during that time with gusts of 25 to 30 mph anticipated across the region. As a result, a Lake Wind Advisory is in effect for Lake Moultrie. Winds will be tapering off some through the overnight hours as cold advection slows down. Temperature-wise: Strong cold advection drives the 850 mb temps down into the -2C to -4C range by morning. This is far below normal, which should be around 8.5C to 8.7C. Along with diminishing winds and clearing skies, lows will drop through the 30s for all areas away from the coast with the coldest readings well inland. Persistent winds and dry incoming air mass will limit frost development to no more than maybe a little patchy coverage late near the US-301 corridor. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Aloft, a large trough will pivot offshore Tuesday, shifting further away from the region while a zonal flow takes place across the Southeast United States through mid-week. At the sfc, high pressure across the South-central United States will extend east across Gulf Coast states and Carolinas Tuesday into Wednesday, before a cold front arrives from the north/northwest by early Thursday. Conditions will remain dry locally through the middle of the week while a west-northwest downslope wind prevails along the eastern edge of the high centered to our west, even as the cold front pushes into the local area by early Thursday. Despite ample sfc heating under clear skies, temps will struggle to warm significantly on Tuesday while weak cold air advection wanes across the region. In general, high temps should only peak in the upper 50s to lower 60s (warmest across southeast Georgia). Although temps are cooler during peak heating, dry air should lead to afternoon RH values between 20- 25% away from the coast Tuesday afternoon. Sfc winds are expected to remain below 10 mph though, so fire wx concerns should be limited. Sfc winds should slowly turn southwest Tuesday night into Wednesday, offsetting some radiational cooling at night and resulting in airmass modification on Wednesday ahead of an arriving cold front. In general, Tuesday night lows should dip into the upper 30s/lower 40s inland to mid-upper 40s near the coast. On Wednesday, high temps should peak in the lower 70s with sunny conditions in place. Guidance indicates a dry cold front pushing across the region Wednesday night, likely becoming positioned along or just south of the local area by daybreak Thursday. Despite northerly winds post fropa, sfc temps should peak in the lower 70s under partly sunny skies in advance of a low pressure system developing and shifting eastward across the northern Gulf of Mexico heading into late week. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The weather becomes more active as we head into late week, although still some forecast details to hash out. An upper wave is expected to pass across the Southeast United States early Friday through early Saturday, forcing an area of low pressure across the northeast Gulf to possibly strengthen while tracking over/near the Georgia and South Carolina coasts. PWATs should increase to around 1.25 inches as the system nears, and with strong isentropic ascent and a lingering front across the area, should promote showers to develop locally Thursday night into Friday morning. Scattered to numerous showers are now forecast to occur for most areas Friday and Friday evening, before precip activity trends offshore with the sfc low pulling away Saturday. Some guidance suggests some modest instability developing near the coast and offshore as the low tracks near the region, so a few embedded thunderstorms are possible along the immediate coast. The aforementioned low should continue to depart the region late weekend as high pressure builds inland. Aside from some lingering showers Saturday morning into early afternoon, precip chances should become confined to the coastal waters by Saturday evening. Dry conditions should then prevail Sunday with high pressure in place. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR conditions anticipated through 00Z Wednesday. Gusty NW winds peaking around 25 kt or so much of tonight, will diminish to around 10 kt by 08-10Z Tuesday, as cold advection diminishes and the gradient slackens some. Extended Aviation Outlook: VFR conditions are expected Tuesday night through Thursday. Flight restrictions are possible at KCHS/KJZI/KSAV terminals Thursday night into Friday as showers/low clouds develop with a passing low pressure system. && .MARINE... Strong high pressure building into the region tonight will lead to a period of gusty northwesterly winds later this evening into the overnight hours. Gale force gusts are anticipated in all coastal waters outside of Charleston Harbor...Small Craft Advisory conditions in the Harbor. Seas will build this evening and peak during the early overnight hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions will improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston County waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is then expected to pass near/off the Southeast Coast Friday into Saturday, likely contributing to deteriorating marine conditions across local waters this weekend. Small Craft Advisories should be needed across most waters, but the track/strength of the low pressure system will play a large role in overall impacts along the Southeast Coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory until 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Warning from 10 PM this evening to 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173135 (Received by flhurricane at: 3:47 PM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 331 PM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area tonight and prevail into Thursday. A storm system could impact the area Friday and Saturday, before high pressure returns early next week. && .NEAR TERM /THROUGH TONIGHT/... Afternoon composite analysis reveals a fairly strong short-wave trough/1.5 PV anomaly diving through the Appalachians driving mid level height falls into the Carolinas and driving fairly cool air (-2C to -4C H8 air) into the region. Secondary surface boundary/dewpoint boundary appears to be passing through the region as of this writing ad surface dewpoints have dropped into the 40s for most areas. There is another band of thicker cloud cover pressing into the Carolinas and Mid Atlantic region along with several pockets of radar returns...all along the leading edge of the upper height falls and upper jet axis. However, no reports of precip across the region thus far owing to the degree of dry lower level air. Tonight: Aforementioned short-wave trough will be swinging through the Carolinas and Mid Atlantic region during the course of the evening and off the coast overnight. Strongest larger scale forcing for ascent will be well to our north, although again I`m not anticipating much in the way of precip even through the Mid Atlantic. Bigger issue for us will be a period of gustier winds and decent cold advection as a large of high pressure (across the central CONUS today) expands into the Gulf Coast and southeast CONUS in the wake of the trough. Tightening pressure gradient (4-5 millibars across the CWA later this evening into the overnight) will lead to a period of gustier winds during that time with gusts of 25 to 30 mph anticipated through inland areas and likely gale force in the coastal waters outside of the Harbor. Going Lake Wind Advisory for Lake Moultrie and marine headlines appear well placed with no changes anticipated. Winds will be tapering off through the overnight hours. Temperature-wise: Strong cold advection drives H8 temps down into the -2C to -4C range by morning. Along with diminishing winds and clearing skies, lows will drop through the 30s for all areas away from the coast with the coldest readings well inland. Persistent winds and dry incoming air mass will limit frost development with no headline planned. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... Aloft, a large trough will pivot offshore Tuesday, shifting further away from the region while a zonal flow takes place across the Southeast United States through mid-week. At the sfc, high pressure across the South-central United States will extend east across Gulf Coast states and Carolinas Tuesday into Wednesday, before a cold front arrives from the north/northwest by early Thursday. Conditions will remain dry locally through the middle of the week while a west-northwest downslope wind prevails along the eastern edge of the high centered to our west, even as the cold front pushes into the local area by early Thursday. Despite ample sfc heating under clear skies, temps will struggle to warm significantly on Tuesday while weak cold air advection wanes across the region. In general, high temps should only peak in the upper 50s to lower 60s (warmest across southeast Georgia). Although temps are cooler during peak heating, dry air should lead to afternoon RH values between 20- 25% away from the coast Tuesday afternoon. Sfc winds are expected to remain below 10 mph though, so fire wx concerns should be limited. Sfc winds should slowly turn southwest Tuesday night into Wednesday, offsetting some radiational cooling at night and resulting in airmass modification on Wednesday ahead of an arriving cold front. In general, Tuesday night lows should dip into the upper 30s/lower 40s inland to mid-upper 40s near the coast. On Wednesday, high temps should peak in the lower 70s with sunny conditions in place. Guidance indicates a dry cold front pushing across the region Wednesday night, likely becoming positioned along or just south of the local area by daybreak Thursday. Despite northerly winds post fropa, sfc temps should peak in the lower 70s under partly sunny skies in advance of a low pressure system developing and shifting eastward across the northern Gulf of Mexico heading into late week. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The weather becomes more active as we head into late week, although still some forecast details to hash out. An upper wave is expected to pass across the Southeast United States early Friday through early Saturday, forcing an area of low pressure across the northeast Gulf to possibly strengthen while tracking over/near the Georgia and South Carolina coasts. PWATs should increase to around 1.25 inches as the system nears, and with strong isentropic ascent and a lingering front across the area, should promote showers to develop locally Thursday night into Friday morning. Scattered to numerous showers are now forecast to occur for most areas Friday and Friday evening, before precip activity trends offshore with the sfc low pulling away Saturday. Some guidance suggests some modest instability developing near the coast and offshore as the low tracks near the region, so a few embedded thunderstorms are possible along the immediate coast. The aforementioned low should continue to depart the region late weekend as high pressure builds inland. Aside from some lingering showers Saturday morning into early afternoon, precip chances should become confined to the coastal waters by Saturday evening. Dry conditions should then prevail Sunday with high pressure in place. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... VFR conditions anticipated through the TAF period. A touch of gustiness will impact the terminals this afternoon. Pressure gradient tightens this evening with surface high pressure building into the region and strong cold advection. Northwest winds develop with gusts to around 25 kts this evening and much of the overnight. Winds aloft increase as well, and there could be some LLWS that develops. But given the anticipated gustiness at the surface and decent mixing, LLWS has not been added to the forecasts at this time. As the pressure gradient and CAA decreases late tonight, winds should decrease to around 10 kts by 9Z. Extended Aviation Outlook: VFR conditions are expected Tuesday afternoon through Thursday. Flight restrictions are possible at KCHS/KJZI/KSAV terminals Thursday night into Friday as showers/low clouds develop with a passing low pressure system. && .MARINE... Strong high pressure building into the region tonight will lead to a period of gusty northwesterly winds later this evening into the overnight hours. Gale force gusts are anticipated in all coastal waters outside of Charleston Harbor...Small Craft Advisory conditions in the Harbor. Seas will build this evening and peak during the early overnight hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions will improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston County waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is then expected to pass near/off the Southeast Coast Friday into Saturday, likely contributing to deteriorating marine conditions across local waters this weekend. Small Craft Advisories should be needed across most waters, but the track/strength of the low pressure system will play a large role in overall impacts along the Southeast Coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Warning from 10 PM this evening to 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173124 (Received by flhurricane at: 1:30 PM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 129 PM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area today and prevail into Thursday. A storm system could impact the area late in the week. && .NEAR TERM /THROUGH TONIGHT/... No substantial changes were made to the going forecast. I did tweak/raise forecast high temps for this afternoon, particularly across the Charleston tri-county where temps have warmed into the lower 70s most areas. Previous discussion... Morning analysis reveals the main surface boundary well out into the Atlantic, arcing down through northern Florida, with some shower activity still ongoing. There is a secondary surface trough/dewpoint boundary about to slip through the region, turning winds more northerly and dropping dewpoints into the 40s and even some 30s. Boundary will be advancing through the CWA through the rest of the day ushering in cooler and substantially drier air into the region. Per satellite imagery, cloud cover is thinning west to east, although there may be another push of thicker cloud cover into the region through the afternoon. Temperature-wise: Certainly cooler than in recent days, although we should be about to reach the upper 60s to lower 70s before the arrival of the cooler air. Tonight: Pressure gradient will increase to around 5 mbs across the forecast area by mid-evening. The forecast will feature NW wind gusts between 20-25 mph during the evening. In addition, strong CAA is forecast overnight. In fact, the H85 temperature over KCHS and KSAV will cool from 5C at 0Z to near -4C by 6Z. CAA will end late tonight with the pressure gradient relaxing through the rest of the night. Given the fresh CAA, decreasing winds, and clear sky, low temperatures are expected to range around 10 degrees below normal. Using a blend of MOS, low temperatures may approach freezing across a corridor from Jenkins to Allendale Counties. However, winds in excess of 5 mph and RH below 60 percent will not favor frost development. Min temperatures should favor values in the mid 30s along the I-95 corridor to around 40 degrees across the coastal counties. Lake Winds: In the wake of a secondary cold front, a steep pressure gradient and strong cold air advection will rapidly develop across Lake Moultrie this evening, decreasing late tonight. Northwest wind gusts are forecast to gust to around 25 mph tonight. A Lake Wind Advisory has been issued from 8 PM until 8 AM. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... High pressure will largely dominate the surface pattern during this period, although a dry cold front will pass through late Wednesday night into Thursday morning. Air mass remains dry and there are no notable forcing mechanisms in play, so rain-free conditions are expected through Thursday. Temperatures will be coolest on Tuesday when highs top out in the upper 50s to low 60s, before moderating back to around normal. Lows are forecast to be in the upper 30s to low/mid 40s Tuesday night, then more mild in the mid 40s to lower 50s for Wednesday night. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... Weather becomes more active as we head into late week, although still some forecast details to hash out. Upper wave is expected to pass across the Southeast Friday into Friday night. At the surface, an area of low pressure is expected to develop and possibly strengthen while moving near/off the Georgia and South Carolina coasts. PWats creep up to around 1.25 inches, and with strong isentropic ascent, showers should break out late Thursday night/Friday morning and continue through the day and into Friday night. This event should bring a decent amount of rain to the area. Consensus keeps instability largely offshore so no thunder is included in the forecast at this time. The aforementioned low should continue to depart over the weekend as high pressure builds inland. Aside from some lingering showers Saturday morning, rain chances should become confined to the coastal waters. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR conditions anticipated through the TAF period. A touch of gustiness will impact the terminals this afternoon. Pressure gradient tightens this evening with surface high pressure building into the region and strong cold advection. Northwest winds develop with gusts to around 25 kts this evening and much of the overnight. Winds aloft increase as well, and there could be some LLWS that develops. But given the anticipated gustiness at the surface and decent mixing, LLWS has not been added to the forecasts at this time. As the pressure gradient and CAA decreases late tonight, winds should decrease to around 10 kts by 9Z. Extended Aviation Outlook: Flight restrictions in low clouds and showers possible Friday into Friday night. && .MARINE... Today, a cold front will sweep across the marine zones early this morning. Northwest winds should favor values of 10 to 15 kts this morning, decreasing to 5 to 10 kts this afternoon. Wave heights are forecast to remain between 1 to 2 ft today. Tonight, a secondary cold front is expected to push across the marine zones this evening. Northwest winds will rapidly strengthen through the evening, with gales developing outside the CHS Harbor by late this evening. A Gale Warning has been posted for all waters outside the CHS Harbor from 10 PM to 9 AM. A Small Craft Advisory has been issued for the CHS Harbor from 10 PM to 6 AM. Seas should build through most of the night. Peak wave heights are expected during the pre-dawn hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions should markedly improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston county waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is expected to pass near/off the Southeast coast Friday into Saturday. Still uncertainty with this system, but there is potential for conditions to reach advisory levels again. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Warning from 10 PM this evening to 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173115 (Received by flhurricane at: 10:41 AM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1028 AM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area today and prevail into Thursday. A storm system could impact the area late in the week. && .NEAR TERM /THROUGH TONIGHT/... Morning analysis reveals the main surface boundary well out into the Atlantic, arcing down through northern Florida, with some shower activity still ongoing. There is a secondary surface trough/dewpoint boundary about to slip through the region, turning winds more northerly and dropping dewpoints into the 40s and even some 30s. Boundary will be advancing through the CWA through the rest of the day ushering in cooler and substantially drier air into the region. Per satellite imagery, cloud cover is thinning west to east, although there may be another push of thicker cloud cover into the region through the afternoon. Temperature-wise: Certainly cooler than in recent days, although we should be about to reach the upper 60s to lower 70s before the arrival of the cooler air. Tonight: Pressure gradient will increase to around 5 mbs across the forecast area by mid-evening. The forecast will feature NW wind gusts between 20-25 mph during the evening. In addition, strong CAA is forecast overnight. In fact, the H85 temperature over KCHS and KSAV will cool from 5C at 0Z to near -4C by 6Z. CAA will end late tonight with the pressure gradient relaxing through the rest of the night. Given the fresh CAA, decreasing winds, and clear sky, low temperatures are expected to range around 10 degrees below normal. Using a blend of MOS, low temperatures may approach freezing across a corridor from Jenkins to Allendale Counties. However, winds in excess of 5 mph and RH below 60 percent will not favor frost development. Min temperatures should favor values in the mid 30s along the I-95 corridor to around 40 degrees across the coastal counties. Lake Winds: In the wake of a secondary cold front, a steep pressure gradient and strong cold air advection will rapidly develop across Lake Moultrie this evening, decreasing late tonight. Northwest wind gusts are forecast to gust to around 25 mph tonight. A Lake Wind Advisory has been issued from 8 PM until 8 AM. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... High pressure will largely dominate the surface pattern during this period, although a dry cold front will pass through late Wednesday night into Thursday morning. Air mass remains dry and there are no notable forcing mechanisms in play, so rain-free conditions are expected through Thursday. Temperatures will be coolest on Tuesday when highs top out in the upper 50s to low 60s, before moderating back to around normal. Lows are forecast to be in the upper 30s to low/mid 40s Tuesday night, then more mild in the mid 40s to lower 50s for Wednesday night. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... Weather becomes more active as we head into late week, although still some forecast details to hash out. Upper wave is expected to pass across the Southeast Friday into Friday night. At the surface, an area of low pressure is expected to develop and possibly strengthen while moving near/off the Georgia and South Carolina coasts. PWats creep up to around 1.25 inches, and with strong isentropic ascent, showers should break out late Thursday night/Friday morning and continue through the day and into Friday night. This event should bring a decent amount of rain to the area. Consensus keeps instability largely offshore so no thunder is included in the forecast at this time. The aforementioned low should continue to depart over the weekend as high pressure builds inland. Aside from some lingering showers Saturday morning, rain chances should become confined to the coastal waters. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... Prior to the 12Z TAFs: Based of IR satellite and surface observations, the cold front was located near KJZI, pushing east. Winds in the wake of the front will shift from the northwest at 10 kts with VFR conditions. Winds over KSAV are forecast to develop gusts to around 20 kts by 18Z, remaining through the rest of the day. This evening, the pressure gradient will increase with strong CAA. Northwest winds are forecast to strengthen early this evening, with gusts around 25 kts. As the pressure gradient and CAA decreases late tonight, winds should decrease to around 10 kts by 9Z. Extended Aviation Outlook: Flight restrictions in low clouds and showers possible Friday into Friday night. && .MARINE... Today, a cold front will sweep across the marine zones early this morning. Northwest winds should favor values of 10 to 15 kts this morning, decreasing to 5 to 10 kts this afternoon. Wave heights are forecast to remain between 1 to 2 ft today. Tonight, a secondary cold front is expected to push across the marine zones this evening. Northwest winds will rapidly strengthen through the evening, with gales developing outside the CHS Harbor by late this evening. A Gale Warning has been posted for all waters outside the CHS Harbor from 10 PM to 9 AM. A Small Craft Advisory has been issued for the CHS Harbor from 10 PM to 6 AM. Seas should build through most of the night. Peak wave heights are expected during the pre-dawn hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions should markedly improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston county waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is expected to pass near/off the Southeast coast Friday into Saturday. Still uncertainty with this system, but there is potential for conditions to reach advisory levels again. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Warning from 10 PM this evening to 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173107 (Received by flhurricane at: 7:48 AM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 737 AM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area today and prevail into Thursday. A storm system could impact the area late in the week. && .NEAR TERM /THROUGH TONIGHT/... As of 730 AM, based of IR satellite and surface observations, the cold front was located near the SC Lowcountry coast, pushing east. Winds in the wake of the front may surge to 10-15 mph early this morning, then settle to 10 mph or less by mid- morning. KCLX detected a few showers over outer GA waters, expected to push east of the marine zones by 9 AM. During the daylight hours today, winds will remain from the west- northwest with a gradual decrease in cloud cover. Given the increasing insolation and 1000-850 mb thicknesses of 1355 m or greater through this afternoon, high temperatures should range around 70 degrees. Near term guidance indicates a secondary cold front will sweep across the forecast area late this afternoon into early this evening. In the wake of the front, the pressure gradient will increase to around 5 mbs across the forecast area by mid-evening. The forecast will feature NW wind gusts between 20-25 mph during the evening. In addition, strong CAA is forecast overnight. In fact, the H85 temperature over KCHS and KSAV will cool from 5C at 0Z to near -4C by 6Z. CAA will end late tonight with the pressure gradient relaxing through the rest of the night. Given the fresh CAA, decreasing winds, and clear sky, low temperatures are expected to range around 10 degrees below normal. Using a blend of MOS, low temperatures may approach freezing across a corridor from Jenkins to Allendale Counties. However, winds in excess of 5 mph and RH below 60 percent will not favor frost development. Min temperatures should favor values in the mid 30s along the I-95 corridor to around 40 degrees across the coastal counties. Lake Winds: In the wake of a secondary cold front, a steep pressure gradient and strong cold air advection will rapidly develop across Lake Moultrie this evening, decreasing late tonight. Northwest wind gusts are forecast to gust to around 25 mph tonight. A Lake Wind Advisory has been issued from 8 PM until 8 AM. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... High pressure will largely dominate the surface pattern during this period, although a dry cold front will pass through late Wednesday night into Thursday morning. Air mass remains dry and there are no notable forcing mechanisms in play, so rain-free conditions are expected through Thursday. Temperatures will be coolest on Tuesday when highs top out in the upper 50s to low 60s, before moderating back to around normal. Lows are forecast to be in the upper 30s to low/mid 40s Tuesday night, then more mild in the mid 40s to lower 50s for Wednesday night. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... Weather becomes more active as we head into late week, although still some forecast details to hash out. Upper wave is expected to pass across the Southeast Friday into Friday night. At the surface, an area of low pressure is expected to develop and possibly strengthen while moving near/off the Georgia and South Carolina coasts. PWats creep up to around 1.25 inches, and with strong isentropic ascent, showers should break out late Thursday night/Friday morning and continue through the day and into Friday night. This event should bring a decent amount of rain to the area. Consensus keeps instability largely offshore so no thunder is included in the forecast at this time. The aforementioned low should continue to depart over the weekend as high pressure builds inland. Aside from some lingering showers Saturday morning, rain chances should become confined to the coastal waters. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... Prior to the 12Z TAFs: Based of IR satellite and surface observations, the cold front was located near KJZI, pushing east. Winds in the wake of the front will shift from the northwest at 10 kts with VFR conditions. Winds over KSAV are forecast to develop gusts to around 20 kts by 18Z, remaining through the rest of the day. This evening, the pressure gradient will increase with strong CAA. Northwest winds are forecast to strengthen early this evening, with gusts around 25 kts. As the pressure gradient and CAA decreases late tonight, winds should decrease to around 10 kts by 9Z. Extended Aviation Outlook: Flight restrictions in low clouds and showers possible Friday into Friday night. && .MARINE... Today, a cold front will sweep across the marine zones early this morning. Northwest winds should favor values of 10 to 15 kts this morning, decreasing to 5 to 10 kts this afternoon. Wave heights are forecast to remain between 1 to 2 ft today. Tonight, a secondary cold front is expected to push across the marine zones this evening. Northwest winds will rapidly strengthen through the evening, with gales developing outside the CHS Harbor by late this evening. A Gale Warning has been posted for all waters outside the CHS Harbor from 10 PM to 9 AM. A Small Craft Advisory has been issued for the CHS Harbor from 10 PM to 6 AM. Seas should build through most of the night. Peak wave heights are expected during the pre-dawn hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions should markedly improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston county waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is expected to pass near/off the Southeast coast Friday into Saturday. Still uncertainty with this system, but there is potential for conditions to reach advisory levels again. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Warning from 10 PM this evening to 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173087 (Received by flhurricane at: 4:36 AM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 418 AM EDT Mon Mar 18 2024 .SYNOPSIS... High pressure will build over the area today and prevail into Thursday. A storm system could impact the area late in the week. && .NEAR TERM /THROUGH TONIGHT/... As of 415 AM, IR satellite and sfc observations indicated that a cold front was pushing east across inland GA and SC. The front is on pace to push offshore before daybreak. In addition, KCLX detected isolated light patches of rain over the coast of Charleston County and over portions of the nearshore waters. Based on radar trends and recent runs of the HRRR, rain will steadily push east and north of the forecast area before sunrise this morning. During the daylight hours today, winds will remain from the west- northwest with a gradual decrease in cloud cover. Given the increasing insolation and 1000-850 mb thicknesses of 1355 m or greater through this afternoon, high temperatures should range around 70 degrees. Near term guidance indicates a secondary cold front will sweep across the forecast area late this afternoon into early this evening. In the wake of the front, the pressure gradient will increase to around 5 mbs across the forecast area by mid-evening. The forecast will feature NW wind gusts between 20-25 mph during the evening. In addition, strong CAA is forecast overnight. In fact, the H85 temperature over KCHS and KSAV will cool from 5C at 0Z to near -4C by 6Z. CAA will end late tonight with the pressure gradient relaxing through the rest of the night. Given the fresh CAA, decreasing winds, and clear sky, low temperatures are expected to range around 10 degrees below normal. Using a blend of MOS, low temperatures may approach freezing across a corridor from Jenkins to Allendale Counties. However, winds in excess of 5 mph and RH below 60 percent will not favor frost development. Min temperatures should favor values in the mid 30s along the I-95 corridor to around 40 degrees across the coastal counties. Lake Winds: In the wake of a secondary cold front, a steep pressure gradient and strong cold air advection will rapidly develop across Lake Moultrie this evening, decreasing late tonight. Northwest wind gusts are forecast to gust to around 25 mph tonight. A Lake Wind Advisory has been issued from 8 PM until 8 AM. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... High pressure will largely dominate the surface pattern during this period, although a dry cold front will pass through late Wednesday night into Thursday morning. Air mass remains dry and there are no notable forcing mechanisms in play, so rain-free conditions are expected through Thursday. Temperatures will be coolest on Tuesday when highs top out in the upper 50s to low 60s, before moderating back to around normal. Lows are forecast to be in the upper 30s to low/mid 40s Tuesday night, then more mild in the mid 40s to lower 50s for Wednesday night. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... Weather becomes more active as we head into late week, although still some forecast details to hash out. Upper wave is expected to pass across the Southeast Friday into Friday night. At the surface, an area of low pressure is expected to develop and possibly strengthen while moving near/off the Georgia and South Carolina coasts. PWats creep up to around 1.25 inches, and with strong isentropic ascent, showers should break out late Thursday night/Friday morning and continue through the day and into Friday night. This event should bring a decent amount of rain to the area. Consensus keeps instability largely offshore so no thunder is included in the forecast at this time. The aforementioned low should continue to depart over the weekend as high pressure builds inland. Aside from some lingering showers Saturday morning, rain chances should become confined to the coastal waters. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... Prior to the 6Z TAFs: KSAV observed IFR ceilings. IR satellite and upstream observations to KSAV indicated patches of MVFR ceilings. The KSAV TAF will feature IFR ceilings with a TEMPO from 7-11Z for MVFR ceiling. AT KCHS/KJZI, KCLX detect light rain across the terminals, unlikely to limit visibility under VFR. A cold front is timed to sweep across the terminals just prior to sunrise, resulting in winds to shift from the NW by 11Z. This evening, the pressure gradient will increase with strong CAA. Northwest winds are forecast to strengthen early this evening, with gusts around 25 kts. Extended Aviation Outlook: Flight restrictions in low clouds and showers possible Friday into Friday night. && .MARINE... Today, a cold front will sweep across the marine zones early this morning. Northwest winds should favor values of 10 to 15 kts this morning, decreasing to 5 to 10 kts this afternoon. Wave heights are forecast to remain between 1 to 2 ft today. Tonight, a secondary cold front is expected to push across the marine zones this evening. Northwest winds will rapidly strengthen through the evening, with gales developing outside the CHS Harbor by late this evening. A Gale Warning has been posted for all waters outside the CHS Harbor from 10 PM to 9 AM. A Small Craft Advisory has been issued for the CHS Harbor from 10 PM to 6 AM. Seas should build through most of the night. Peak wave heights are expected during the pre-dawn hours, ranging from 3 ft within 10 NM from shore to 7 ft across portions of the outer GA waters. Tuesday through Saturday: Marine conditions should markedly improve on Tuesday, although there will be another brief wind surge Tuesday night with gusts to near advisory criteria, especially over the Charleston county waters. A somewhat enhanced pressure gradient could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels through Thursday. An area of low pressure is expected to pass near/off the Southeast coast Friday into Saturday. Still uncertainty with this system, but there is potential for conditions to reach advisory levels again. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for SCZ045. MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Warning from 10 PM this evening to 9 AM EDT Tuesday for AMZ350-352-354-374. && $$ |
#1173072 (Received by flhurricane at: 2:27 AM 18.Mar.2024) AFDCHS Area Forecast Discussion National Weather Service Charleston SC 211 AM EDT Mon Mar 18 2024 .SYNOPSIS... A disturbance will track over the area tonight. A cold front will move offshore early Monday morning. High pressure will then build over the area on Monday and prevail into Thursday. A storm system could impact the area late in the week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Based of radar trends, lingering light rain should push over the Atlantic or north of the forecast area by 3 AM. The forecast update will feature much lower PoPs, decreasing into the single digits before sunrise. Temperatures are on pace to range from the low 50s inland to the upper 50s along the coast by daybreak Monday. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... Aloft, a large/high amplitude trough will sweep across the Mid- Atlantic and Southeast late Monday, before a more zonal flow prevails midweek between broad troughing across the Northeast and broad ridging across the Gulf of Mexico and Caribbean. At the sfc, a cold front will be placed offshore Monday while high pressure centered across the Central United States slides south toward the Gulf of Mexico late Monday, then extends eastward across the Gulf Coast and into the western Atlantic midweek. Monday: Lingering moisture post fropa could lead to a few showers along coastal areas during the morning, while ample forcing approaches with the upper trough. However, expect precip to shift offshore by around noon as a dry westerly flow develops across the region along the southern edge of maximum forcing. Temps will be on a cooling trend, peaking in the mid 60s inland to lower 70s early day. Strong cold air advection is expected across the region overnight as the upper trough axis pivots offshore. Sfc temps will respond, dipping into the low-mid 30s inland to upper 30s/lower 40s near the coast late. Despite these colder temps, frost will not be a concern due to gusty winds associated with favorable low-lvl mixing into 35-40 kt low-lvl wind fields. A Freeze Watch is also not expected as potential coverage for freezing temps remains too small and the duration too short. However, gusty winds could approach 25- 35 mph across Lake Moultrie during overnight hours. A Lake Wind Advisory will likely be needed. Tuesday and Wednesday: Conditions will remain dry through midweek as a west-northwest downslope wind spreads across the local area along the eastern edge of high pressure sliding towards the northern Gulf of Mexico. Despite ample sfc heating under clear skies, temps will struggle to warm significantly Tuesday afternoon, only peaking in the upper 50s/lower 60s. Heading into Wednesday night, sfc winds begin to turn southwest as the high becomes more centered across the Gulf. This should offset radiational cooling, favoring overnight lows noticeably warmer than the previous night, generally in the upper 30s/lower 40s inland to mid-upper 40s near the coast. By Wednesday, sunny skies and a warmer southwest wind will likely support some airmass modification across the Southeast. High temps are expected to become noticeably warmer, generally peaking in the low-mid 70s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Quiet and dry weather is expected to persist into Thursday, then forecast uncertainty increases for the late week time period due to large spread between model solutions. The general pattern would indicate an upper wave passing across the Gulf coast states and through the Southeast, though the strength of this feature is in question. At the surface, an area of low pressure could pass over or just south of the area, before shifting north offshore and/or hugging the coast Friday into Saturday. This path would keep the local area on the cooler and less unstable side of the system, suggesting mainly scattered to numerous showers across land with the potential of some coastal impacts as the low traverses near the area. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... Prior to the 6Z TAFs: KSAV observed IFR ceilings. IR satellite and upstream observations to KSAV indicated patches of MVFR ceilings. The KSAV TAF will feature IFR ceilings with a TEMPO from 7-11Z for MVFR ceiling. AT KCHS/KJZI, KCLX detect light rain across the terminals, unlikely to limit visibility under VFR. A cold front is timed to sweep across the terminals just prior to sunrise, resulting in winds to shift from the NW by 11Z. This evening, the pressure gradient will increase with strong CAA. Northwest winds are forecast to strengthen early this evening, with gusts around 25 kts. Extended Aviation Outlook: Gusty northwest winds are expected Monday night at KCHS/KJZI/KSAV terminals. Otherwise, VFR conditions are expected. && .MARINE... Tonight: West to southwest winds will persist with speeds less than 15 kt and seas 1-3 ft. Monday through Friday: A cold front will be placed offshore Monday, setting up cold air advection across local waters for much of the day as a west wind occurs. Winds/seas will ramp up considerably Monday night as a high amplitude trough shifts offshore and cold air advection peaks. At least high-end Small Craft Advisory level winds are expected across all waters. Strong mixing profiles tapping into 40 kt low-lvl winds suggests west/northwest winds could gust to gale force for at least a few hours Monday night, especially beyond 10 nm from the coast. Given the trend, a Gale Watch has been issued for all coastal waters outside the CHS Harbor, where a Small Craft Advisory is in place Monday night. Frequent gusts around 35 kt are possible between 03-13Z for the Gale Watch, but highest winds are anticipated across offshore Georgia waters. Seas should also build to 3-5 ft across nearshore waters and 5-7 ft across offshore Georgia waters. Improvement is expected Tuesday as cold air advection begins to wane, but another surge is possible Tuesday night with conditions approaching Small Craft Advisory levels. A somewhat enhanced pressure gradient under a zonal flow type pattern could support elevated winds through late week, but conditions should remain just below Small Craft Advisory levels until early weekend, when a low pressure system potentially impacts the region. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory from 11 PM this evening to 6 AM EDT Tuesday for AMZ330. Gale Watch from this evening through Tuesday morning for AMZ350-352-354-374. && $$ |