MikeC
Admin
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Loc: Orlando, FL
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With some visible satellite imagery, it's looking like maybe no development at 11AM, possibly later today, but the split thing has kept it weak, which means it'll likely continue a bit further westward for longer.
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metwannabe
Weather Hobbyist
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Loc: NC
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I know model runs are all but useless at this point but they have every scenario on the table from gulf coast to recurve to everything in between, including dissipation...(if I'm looking at them correctly). One thing for sure with each passing day it does not get it's act together gonna make for some interesting days ahead. Also I thought it looked better this morning, I'm guessing that rotation is upper level and still no sign of surface closed off low?
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Fran, Bertha, Dennis & Floyd (Tag Team)
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MichaelA
Weather Analyst
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Loc: Pinellas Park, FL
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It does look iffy as to whether or not there is a defined LLC yet. Maybe later today or tomorrow.
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Michael
PWS
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adam s
Verified CFHC User
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The longer 91L stays weak the further west the storm will go. If 91L stays weak the greater the chance it may impact the United States.
Edited by adam s (Mon Aug 01 2011 02:13 PM)
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scottsvb
Weather Master
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Loc: fl
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The very broad center of this is near 12.5N and almost 60W.. moving just north of due west or 280deg.
There is a midlevel vortex in the decay T-Storm cluster around 13.8N and 57.5W
2 Things I want to post here.
1. Most of the models really didnt project this to become defined and more developed until later tonight or on Tuesday once it passed thru the islands.
2. I feel the convection needs to form around 13N and 60W this evening around the broad center for this
to develop moreso...otherwise if this is not developed by Tuesday evening,..history says systems dont like
getting developed in the central carribean till they get past 75W.
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Hawkeyewx
Weather Analyst
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91L is not well-organized this morning. A weak swirl came out of the overnight convection and is now approaching the Guadeloupe area while the MCV produces some convection and hangs back to the southeast. Currently, there is only southeast surface flow under that MCV, so no development is imminent.
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danielw
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Loc: Hattiesburg,MS (31.3N 89.3W)
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I'm just checking in and I'm not sure if this weather is the outer fringes of 91L or part of the MCV. Mesoscale Convective Vortice/ Vortex.
This Airport is reporting the highest sustained wind among all of the Airports in the Lesser Antilles.
Current Weather Conditions:
Hewanorra International Airport, Saint Lucia
(TLPL) 13-45N 060-57W 10M
Conditions at
2011.08.01 1500 UTC
Wind from the ENE (070 degrees) at 21 MPH (18 KT)
Visibility greater than 7 mile(s)
Sky conditions mostly cloudy
Weather Cumulonimbus clouds observed
Temperature 84 F (29 C)
Dew Point 78 F (26 C)
Relative Humidity 83%
Pressure (altimeter) 29.85 in. Hg (1011 hPa)
Other Caribbean Airport Observations may be viewed here.
ANOTHER HURRICANE
HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THE DISTURBANCE THIS
AFTERNOON. IF THE SYSTEM BECOMES A TROPICAL CYCLONE TODAY...
TROPICAL STORM WARNINGS WOULD BE ISSUED FOR PORTIONS OF THE
NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS ON VERY SHORT
NOTICE. INTERESTS IN THESE AREAS SHOULD CLOSELY MONITOR THE
PROGRESS OF THIS SYSTEM. REGARDLESS OF TROPICAL CYCLONE DEVELOPMENT
OF THIS SYSTEM WILL BRING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO
PORTIONS OF THE LESSER ANTILLES TODAY AND TONIGHT.
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doug
Weather Analyst
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Loc: parrish,fl
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The visible does show what may be low level banding around some new convection firing near 15.5/59.5, a rather exposed area NW of the major convective area where a midlevel cyclonic rotation is taking place. The area to the east is also showing signs of conforming to the area mentioned above.
Once this does start to spin up, I think it will become a huge circulation system; there is so much for it to play with, and rather benign conditions in the immediate future.
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doug
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danielw
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Loc: Hattiesburg,MS (31.3N 89.3W)
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Recon is airborne and we have a data stream so far.
They released a dropsonde just SE of St Croix and the lower level winds appear to be connected to the tropical wave. I'm not a Met so it's a bit hard to define wave connected winds.
Lower level, below 10,000 feet, of dropsonde information is below.
Coordinates: 17.4N 63.9W
Location: 158 miles (255 km) to the ESE (116°) from San Juan, Puerto Rico (USA)
Significant Wind Levels...
Level Wind Direction Wind Speed
1013mb (Surface) 60° (from the ENE) 21 knots (24 mph)
966mb 60° (from the ENE) 19 knots (22 mph)
943mb 70° (from the ENE) 22 knots (25 mph)
929mb 75° (from the ENE) 18 knots (21 mph)
902mb 75° (from the ENE) 25 knots (29 mph)
** Wave connected winds?? above this line**
875mb 95° (from the E) 19 knots (22 mph)
850mb 90° (from the E) 26 knots (30 mph)
824mb 90° (from the E) 22 knots (25 mph)
814mb 105° (from the ESE) 26 knots (30 mph)
791mb 75° (from the ENE) 23 knots (26 mph)
781mb 90° (from the E) 24 knots (28 mph)
771mb 75° (from the ENE) 28 knots (32 mph)
735mb 90° (from the E) 29 knots (33 mph)
678mb (10,000 ft) 85° (from the E) 30 knots (35 mph)
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danielw
Moderator
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Loc: Hattiesburg,MS (31.3N 89.3W)
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
652 AM EDT MON AUG 01 2011
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. AT UPPER
LEVELS...THE SUBEQUATORIAL RIDGE NOW EXTENDS FROM THE TROPICAL
ATLANTIC WESTWARD ACROSS THE ISLAND CHAIN TO THE EASTERN
CARIBBEAN. AT LOW LEVELS...A TROPICAL WAVE/BROAD AREA OF LOW
PRESSURE LIES TO THE EAST OF THE ISLAND CHAIN. THE CONTINUES
TO MONITOR THIS AREA FOR POSSIBILITY OF TROPICAL CYCLOGENESIS.
THIS FEATURE IS GOING TO BE THE FORECAST CHALLENGE...AS IT IS
LIKELY TO SUSTAIN ORGANIZED CONVECTION ACROSS THE EASTERN
CARIBBEAN ISLES.
ALOFT...THE MODELS SHOW SUBEQUATORIAL RIDGE BECOMING WELL
ESTABLISHED THROUGH THURSDAY MORNING...TO ANCHOR AT 250 HPA ON A
CLOSED HIGH JUST SOUTH OF PUERTO RICO. LATER IN THE WEEK IT WILL
THEN MERGE WITH THE SUBTROPICAL RIDGE AS THE LATTER BUILDS ACROSS
THE EASTERN USA TO THE WESTERN ATLANTIC. AS THE RIDGE
PERSISTS/BECOME BETTER ESTABLISHED...IT WILL CONTINUE VENTING DEEP
CONVECTION IN ASSOCIATION WITH SYSTEM ENTERING THE ISLAND CHAIN.
CONVECTIVE ACTIVITY IS TO START ACROSS THE VIRGIN ISLANDS TOMORROW
AFTERNOON...AND MAINLAND PUERTO RICO DURING THE LATE
EVENING/MORNING HOURS. THE GLOBAL GUIDANCE SHOWS MAXIMA OF FOUR TO
SIX INCHES WITH THIS SYSTEM...WITH REGIONAL PEAKING AT EIGHT
TO TEN INCHES. LOOKS LIKE MOST INTENSE IS GOING TO BE ACROSS THE
VIRGIN ISLES-EASTERN/SOUTHERN PUERTO RICO.
DEPENDING ON HOW QUICKLY IT ORGANIZES...THIS SYSTEM MIGHT END UP
ESTABLISHING A MOIST INFLOW AS IT TAPS INTO THE ATLANTIC . THE
MOIST FLUX COULD LAST INTO THURSDAY MORNING...IF NOT LONGER. SO WE
COULD BE FACING 48-60 HRS OF ORGANIZED ACTIVITY. THIS IS GOING TO
BE HEAVY RAINS OVER AN AREA THAT IS SATURATED FROM PREVIOUS
EVENTS. IT IS NOT GOING TO TAKE MUCH TO GENERATE LARGE SCALE
FLOODING.
NEELY...BDM (THE BAHAMAS)
DAVISON...NCEP (USA)
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danielw
Moderator
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Loc: Hattiesburg,MS (31.3N 89.3W)
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PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
954 AM EDT MON AUG 01 2011 (edited~danielw)
VALID 12Z FRI AUG 05 2011 - 12Z MON AUG 08 2011
...THE MODELS ARE ALSO STRUGGLING TO RESOLVE A POTENTIAL TROPICAL
SYSTEM ORIGINATING FROM AN AREA OF LOW PRESSURE CURRENTLY IN THE
VICINITY OF 55-60W LONGITUDE.
OPERATIONAL MODEL TRACKS RANGE FROM
THE CENTRAL GULF IN THE 00Z UKMET TO E OF THE FL PENINSULA IN THE
00Z /ECMWF.
YESTERDAYS /HPC COORDINATED TRACK TO THE E OF THE
NORTHERN BAHAMAS BY DAY 6 SUN IS NOW EASTWARD OF THE CURRENT MODEL ENVELOPE.
PREFER TO AWAIT TODAYS 17Z COORDINATION FOR ANY SIGNIFICANT
CHANGES... WITH THE UPDATED PRELIM FORECAST DEPICTING ONLY A MODEST
WESTWARD ADJUSTMENT BETWEEN CONTINUITY AND THE 00Z /ECMWF ALONG WITH
STRENGTH SIMILAR TO CONTINUITY.
CONSULT THE LATEST TROPICAL
WEATHER OUTLOOK FOR FURTHER INFO REGARDING THIS FEATURE.
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scottsvb
Weather Master
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Loc: fl
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Starting to get a LLC around 15.2N and 60.4W as of this post.
Radar showing a weak circulation along with satellite vis.. but the west
wind is very weak and light right now out to a few miles. Probably will
expand with more convection later this evening. I feel the recon will
head back to this area in 1-2hrs and this might be enough to classify
this as a Tropical Storm.. around 50mph.. pressure.. right now 1007mb
but could be down 1-2more by then.
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Hawkeyewx
Weather Analyst
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The surface spin that shot out from the convective debris this morning is now the center of 91L. This morning the convection was firing around the MCV, but that has hung back to the southeast and will dissipate. New convection is trying to catch up with the surface center, but the environment(dry air, shear) is not idea at the moment.
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scottsvb
Weather Master
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Loc: fl
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I dont think the shear will be much of a player vs the drier air in the carribean.. but the carribean
is suppose to moisten up some over the next 12-36hrs before landfall in Hispaniola-Cuba
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danielw
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Loc: Hattiesburg,MS (31.3N 89.3W)
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At this time it doesn't appear the Recon will be able to close off a circulation. They have made a full pass through the system from NW to SE.
Wind direction and speed data have a trough like appearance, so far. Recon is headed back toward the NW, and what would be the center of the current system.
Latest point:
Time: 18:45:00Z
Coordinates: 14.7N 59.5833W
Acft. Static Air Press: 975.8 mb (~ 28.82 inHg)
Acft. Geopotential Hgt: 287 meters (~ 942 feet)
Extrap. SFC. Press: 1008.3 mb (~ 29.78 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 99° at 19 knots (From the E at ~ 21.8 mph)
Air Temp: 23.7°C (~ 74.7°F)
Dew Pt: 16.4°C (~ 61.5°F)
Peak (10s) Flt. Lvl. Wind: 21 knots (~ 24.1 mph)
SFMR Peak (10s) SFC. Wind: 24 knots (~ 27.6 mph)
SFMR Rain Rate: 2 mm/hr (~ 0.08 in/hr)
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adam s
Verified CFHC User
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Invest 91L is really looking impressive on the latest satellite loop. I expect at the 5pm update this afternoon that Invest 91L will be upgraded to a tropical depression.
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danielw
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Loc: Hattiesburg,MS (31.3N 89.3W)
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I'm not sure they will be able to find what they are looking for. A closed Low level center.
Latest Recon data indicates they may have found a center just east of the following position.
They were able to find a wind shift from the NW to NE. Which is one of the requirements for closing off a Low.
Time: 19:21:30Z
Coordinates: 15.0167N 60.9833W
Acft. Static Air Press: 976.0 mb (~ 28.82 inHg)
Acft. Geopotential Hgt: 279 meters (~ 915 feet)
Extrap. SFC. Press: 1007.4 mb (~ 29.75 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 343° at 9 knots (From the NNW at ~ 10.3 mph)
Air Temp: 23.9°C (~ 75.0°F)
Dew Pt: 22.7°C (~ 72.9°F)
Peak (10s) Flt. Lvl. Wind: 10 knots (~ 11.5 mph)
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metwannabe
Weather Hobbyist
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Posts: 92
Loc: NC
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It just seems to be moving too fast to develop.....that low level swirl appears to keep "shooting" out ahead of the convection.
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Fran, Bertha, Dennis & Floyd (Tag Team)
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Bloodstar
Moderator
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Posts: 462
Loc: Tucson, AZ
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I has the winds, and a nominally closed low, but I think the organization isn't sufficient to declare it a Tropical Storm. The surface feature is located west of the midlevel feature, and the battle between the two features is what's stopping the system from consolidating.
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M. S. Earth and Atmospheric Sciences, Georgia Tech - May 2020
Brookhaven National Laboratory
U. Arizona PhD Student
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Rich B
British Meteorologist
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Posts: 498
Loc: Gloucestershire, England, UK
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System will be classified at 2100z, advisories will be initiated on TS Emily 
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Rich B
SkyWarn UK
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