AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1255 AM EDT MON JUN 27 2011 .SYNOPSIS... A WEAK COLD FRONT WILL MOVE ACROSS SOUTHERN NEW ENGLAND TONIGHT AND MAY BRING WIDELY SCATTERED SHOWERS. HIGH PRESSURE WILL BUILD INTO THE REGION MONDAY AND TUESDAY BRINGING MAINLY DRY AND PLEASANT WEATHER. ANOTHER COLD FRONT WILL LIKELY BRING A ROUND OF SHOWERS/ISOLATED THUNDERSTORMS TO THE REGION TUE NIGHT/EARLY WED...FOLLOWED BY DRY/SEASONABLE WEATHER FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1 AM UPDATE... AREA OF MID CLOUDS ALONG AND S OF THE PIKE WITH PARTIAL CLEARING MOVING IN FROM THE N. THIS CLEARING TREND WILL MOVE SWD ACROSS THE REGION OVERNIGHT. MOST OF THE FOG HAS LIFTED BUT WITH SMALL T/TD DEPRESSIONS...PATCHY FOG WILLIKELY REDEVELOP IN THE TYPICAL FOG PRONE LOCATIONS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... MONDAY... HIGH PRESSURE BUILDS OVER THE REGION...SO EXPECT A DRY DAY. NOTICE THE GFS GENERATES QPF ACROSS CT-RI-SE MASS DURING 18Z-24Z. THIS COMES DESPITE A LACK OF INSTABILITY OR A SUPPORTING UPPER JET...OR EVEN ISENTROPIC PROCESSES. BEST THING WE CAN FIND IS CONVERGENCE AT 925 MB OVERLAYED BY DIVERGENCE AT 850 MB...AND A MOIST LAYER BETWEEN 850 MB AND 800 MB. WITH MIXING EXPECTED TO REACH THIS MOIST LAYER IT IS REASONABLE TO EXPECT DIURNAL CUMULUS BUT NO SHOWERS. TEMPS 13-14C AT 850 MB AND 10C AT 800 MB...ALL POINTING TO FULL MIXING TEMPS IN THE MID 80S. WEAK FLOW WILL ALLOW SEABREEZES TO DEVELOP ALONG THE COASTS SO MAX TEMPS WILL BE COOLER THERE. USED A BLEND OF MOS AND ADDED A COUPLE OF DEGREES TO GET MAX TEMPS 80-85 AWAY FROM THE COAST AND 70S ALONG THE COAST. MONDAY NIGHT... HIGH PRESSURE STILL IN CONTROL AS IT EASES OFF TO THE EAST. A LIGHT SOUTH FLOW DEVELOPS OVERNIGHT. EXPECT MOSTLY CLEAR SKIES...WHICH WILL MEAN FOG OVERNIGHT IN THE VALLEYS AND ALONG THE SOUTH COAST. TEMPS ARE A BLEND OF MOS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... *SHOWERS AND ISOLATED THUNDERSTORMS LIKELY TUE NIGHT/EARLY WED *TEMPERATURES TO AVERAGE NEAR OR JUST BELOW NORMAL FOR MOST OF THE WEEK DETAILS... TUESDAY... A WEAK RIDGE OF HIGH PRESSURE WILL SLOWLY MOVE OFF THE NEW ENGLAND COAST ON TUESDAY...AS A SHORTWAVE/UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. THE BEST DYNAMICS/FORCING SHOULD REMAIN TO OUR WEST DURING THE DAYLIGHT HOURS TUESDAY...SO GENERALLY EXPECT A DRY DAY OTHER THAN PERHAPS A BRIEF SPOT SPRINKLE/SHOWER OR TWO ACROSS THE INTERIOR. SKIES SHOULD BE PARTLY SUNNY ALTHOUGH THERE WILL BE THE TENDENCY FOR MORE CLOUDS AS THE AFTERNOON WEARS ON AS THE DISTURBANCE APPROACHES FROM THE WEST. HIGHS SHOULD BE QUITE COMFORTABLE FOR LATE JUNE...MAINLY IN THE UPPER 70S TO LOWER 80S. TUESDAY NIGHT... THE MODELS ARE IN VERY GOOD AGREEMENT THAT A FAIRLY STRONG SHORTWAVE WILL SWEEP ACROSS THE REGION. THE DYNAMICS/FORCING WITH THIS WAVE APPEAR TO BE ENOUGH TO WARRANT LIKELY POPS FOR A PERIOD OF SHOWERS. WILL ALSO INCLUDE ISOLATED THUNDERSTORMS WITH DECENT JET DYNAMICS AND SOME ELEVATED INSTABILITY. FINALLY...PWAT VALUES ON THE ORDER OF 2 INCHES WILL SUPPORT HEAVY RAIN FROM THE STRONGER SHOWERS AND ISOLATED THUNDERSTORMS. THEREFORE...WE MAY SEE SOME TYPICAL NUISANCE URBAN/POOR DRAINAGE STREET FLOODING. LOW TEMPERATURES WILL MAINLY BE IN THE LOWER TO MIDDLE 60S. WEDNESDAY... IT APPEARS THAT THE SHORTWAVE WILL BE OFF THE COAST BRINGING AN END TO MOST OF THE PRECIPITATION EXITING THE COASTAL PLAIN BY LATE MORNING. OTHERWISE...WE EXPECT A PARTLY SUNNY AND MAINLY DRY DAY. THERE IS A LOW PROBABILITY THAT A FEW POPUP SHOWERS COULD DEVELOP DURING THE HEAT OF THE AFTERNOON...BUT AT THIS POINT IT LOOKS LIKE THERE WILL BE TOO MUCH MID LEVEL DRY AIR. THEREFORE...WILL GO WITH A DRY FORECAST FOR THE REST OF THE DAY. HIGHS SHOULD GENERALLY BE BETWEEN 80 AND 85. THURSDAY AND FRIDAY... A WEAK RIDGE OF HIGH PRESSURE WILL PROVIDE DRY AND BEAUTIFUL SUMMER LIKE WEATHER. HIGHS SHOULD MAINLY BE IN THE UPPER 70S TO LOWER 80S WITH COMFORTABLE HUMIDITY LEVELS. FRIDAY NIGHT THROUGH SUNDAY... LOW CONFIDENCE FORECAST FOR NEXT WEEKEND. THERE ARE SOME INDICATIONS ESPECIALLY ON THE ECMWF THAT A WEAK BACKDOOR COOL FRONT WILL ATTEMPT TO WORK INTO THE REGION. WHILE CONFIDENCE IS LOW...WILL SHOW SOMEWHAT BELOW NORMAL TEMPERATURES WITH HIGHS MAINLY IN THE 70S WITH THE POTENTIAL FOR ONSHORE FLOW. LOW CONFIDENCE ON PRECIPITATION POTENTIAL...BUT THERE COULD BE A FEW SHOWERS FROM TIME TO TIME WITH A BOUNDARY IN THE VICINITY. CERTAINLY NOT EXPECTING A WASHOUT...BUT WILL INCLUDE 20 TO 30 POPS TO COVER THIS POTENTIAL. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT TONIGHT... MEDIUM TO HIGH CONFIDENCE. VFR CONDITIONS THROUGH LATE EVENING ACROSS MOST TERMINALS WITH THE EXCEPTION OF THE HYA/ACK TERMINAL WHERE IFR-LIFR CONDITIONS IN LOW CLOUDS/FOG ARE EXPECTED. AFTER MIDNIGHT...LOCALIZED MVFR-IFR CONDITIONS MAY DEVELOP ACROSS SOME OF THE TERMINALS IN PATCHY GROUND FOG. MONDAY... HIGH CONFIDENCE VFR. EXPECT CUMULUS TO FORM DURING THE MORNING AND LINGER THROUGH AFTERNOON WITH CEILINGS AROUND 4000 FEET. MONDAY NIGHT... HIGH CONFIDENCE VFR THROUGH MIDNIGHT. AFTER THAT...MEDIUM CONFIDENCE WITH DEVELOPING IFR AND LIFR IN FOG ESPECIALLY IN THE CT VALLEY AND ALONG THE SOUTH COAST INCLUDING THE ISLANDS. KBOS TERMINAL... HIGH CONFIDENCE IN MAINLY VFR THROUGH MONDAY. SOUTHEAST WINDS TO BECOME SOUTHWEST THIS EVENING...THEN NORTHWEST AT 5 TO 10 KTS BY DAYBREAK MONDAY. EASTERLY SEA BREEZES LIKELY TO DEVELOP BY LATE MONDAY MORNING OR EARLY AFTERNOON. OUTLOOK...TUESDAY THROUGH FRIDAY... TUESDAY...MEDIUM CONFIDENCE. ANY MVFR-IFR CONDITIONS IN EARLY MORNING LOW CLOUDS/FOG PATCHES SHOULD IMPROVE TO MAINLY VFR ACROSS MOST TERMINALS BY LATE MORNING OR EARLY AFTERNOON. TUESDAY NIGHT...MEDIUM TO HIGH CONFIDENCE. A PERIOD OF MVFR TO IFR CONDITIONS ARE LIKELY IN A PERIOD OF SHOWERS AND PERHAPS ISOLATED THUNDERSTORMS. WEDNESDAY...MEDIUM TO HIGH CONFIDENCE. ANY LEFT OVER MVFR-IFR CONDITIONS IN THE EARLY MORNING SHOULD IMPROVE TO VFR BY LATE MORNING OR EARLY AFTERNOON. THURSDAY AND FRIDAY...MEDIUM TO HIGH CONFIDENCE IN MAINLY VFR. && .MARINE... WINDS AND SEAS REMAIN BELOW SMALL CRAFT LEVELS THROUGH MONDAY NIGHT. AREAS OF FOG WILL LINGER OVER THE WATERS FOR A TIME TONIGHT...ESPECIALLY THE NANTUCKET WATERS...BEFORE DIMINISHING LATER TONIGHT. FOG MAY ALSO DEVELOP MONDAY NIGHT ESPECIALLY AROUND THE CAPE AND ISLANDS. OUTLOOK...TUESDAY THROUGH FRIDAY... RELATIVELY WEAK PRESSURE GRADIENT SHOULD KEEP WINDS AND SEAS GENERALLY BELOW SCA THRESHOLDS MOST IF NOT THE ENTIRE PERIOD. ITS POSSIBLE THAT SOME MARGINAL 5 FOOT SEAS FLIRT WITH THE SOUTHERN OUTER-WATERS FOR A TIME WED INTO EARLY THU. OTHERWISE...THE MAIN CONCERN FOR MARINERS WILL BE FOR REDUCED VISIBILITIES FROM FOG. THIS WILL MAINLY BE ACROSS THE SOUTHERN WATERS DURING THE EARLY TO MID MORNING HOURS OF TUE AND WED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/FRANK