Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 280504 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 104 AM EDT MON JUL 28 2014 .SYNOPSIS...
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A RATHER STRONG AREA OF LOW PRESSURE BY JULY STANDARDS WILL DEVELOP OVER NY AND PA TONIGHT. ITS WARM FRONT WILL BRING A ROUND OF HEAVY SHOWERS AND THUNDERSTORMS EARLY THIS MORNING FOLLOWED BY POSSIBLE STRONG THUNDERSTORMS MONDAY AFTERNOON AS A COLD FRONT APPROACHES FROM THE WEST. BY TUE THE FRONT MOVES OFFSHORE WITH DRY AND MUCH LESS HUMID WEATHER OVERSPREADING THE REGION AND CONTINUING FOR MUCH OF THE REMAINDER OF THE WORKWEEK.
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&& .NEAR TERM /THROUGH TODAY/...
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*** HEAVY RAIN/STORMS EARLY THIS MORNING *** *** FEW STRONG/SEVERE STORMS THIS AFTERNOON *** 1 AM UPDATE... BAND OF SHOWERS/STORMS OVER WESTERN AND CENTRAL NY INTO NYC AND NJ IS ASSOCIATED WITH STRONG MID LEVEL Q-VECTOR CONVERGENCE AS UPPER LOW CLOSES OFF OVER EASTERN GREAT LAKES. MODELS IN GOOD AGREEMENT THAT THIS ACTIVITY WILL LIFT THROUGH SOUTHERN NEW ENGLAND THROUGH THIS MORNING...BEFORE SHIFTING FARTHER N THIS AFTERNOON. MAIN THREAT THIS MORNING IS LOCALIZED FLASH FLOODING FROM HEAVY RAINFALL...IN ADDITION TO FREQUENT LIGHTNING. ALSO CANNOT RULE OUT STRONG WIND GUSTS GIVEN ENVIRONMENT OF RATHER HIGH 0-6KM SHEAR AND DECENT MID LEVEL LAPSE RATES...THOUGH GIVEN TIME OF DAY CONFIDENCE IS LOW THAT STRONG WINDS WILL BE REALIZED. ONCE THIS INITIAL ROUND OF SHOWERS/STORMS LIFTS N BY EARLY AFTERNOON...ATTENTION THEN TURNS TO POSSIBLE REDEVELOPMENT OF SCATTERED SHOWERS/STORMS. MODELS INSISTENT THAT DRY SLOT WILL WORK ITS WAY UP COAST INTO SE NEW ENGLAND...AND DEEPER MOISTURE SHOULD RESIDE ACROSS INTERIOR AS SEEN IN K-INDEX FIELDS. INSTABILITY IS IN QUESTION AS WE ARE NOT CONFIDENT ON HOW MUCH CLEARING WILL OCCUR...IF AT ALL. BUT CONTINUED PRESENCE OF HIGH 0-6KM SHEAR /OVER 35KT/ AND GOOD LOW LEVEL TURNING IN FORECAST HODOGRAPHS SUGGESTS POTENTIAL FOR AT LEAST FEW STRONG OR SEVERE STORMS THIS AFTERNOON. DAMAGING WINDS AND HAIL ARE MAIN THREATS...BUT WE CANNOT RULE OUT AN ISOLATED WEAK TORNADO GIVEN HIGHLY SHEARED ENVIRONMENT AND PRESENCE OF CLOSED UPPER LOW. SYSTEM ALSO HAS HISTORY OF PRODUCING FEW WEAK TORNADOES THUS FAR AS WELL. GIVEN UNCERTAINTY IN AMOUNT OF HEATING...STAYED CLOSE TO MODEL BLEND FOR HIGHS TODAY /70S TO AROUND 80/ WHICH ALSO MATCHES MIXING TO 850 MB /10-11C/.
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&& .SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
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BIG IMPROVEMENT BEHIND THE FRONTAL PASSAGE WITH MUCH LESS HUMID AIRMASS OVERSPREADING THE REGION WITH DEW PTS FALLING INTO THE 50S! THIS WILL SUPPORT LOW TEMPS BY TUE MORNING IN THE MU50S INLAND AND LOW TO MID 60S ALONG THE COAST. DRY WEATHER EXPECTED TUE AS RIDGE OF HIGH PRESSURE BUILDS INTO REGION.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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*/ HIGHLIGHTS... - SLIGHTLY COOL AND DRY INTO THE END OF JULY! - SCATTERED STORMS POSSIBLE ACROSS INTERIOR NEW ENGLAND FOR THURSDAY - DECENT CHANCES FOR WET WEATHER FRIDAY INTO SATURDAY - POSSIBLE DAILY OCCURRENCES OF INTERIOR STORMS INTO NEXT WEEK */ OVERVIEW AND MODEL PREFERENCE... INCREDIBLE PATTERN FOR MID-SUMMER! ENSEMBLE SIGNALS AVERAGING WELL- BELOW NORMAL /-4 TO -5 SD/ FOR BOTH TEMPERATURE AND HUMIDITY ACROSS THE NE CONUS AS A BUCKLED PATTERN PREVAILS WITH PREFERRED TROUGHING ACROSS THE GREAT LAKES NEIGHBORED BY STRONG RIDGING. ANTICIPATING A COOL TO SEASONABLE PATTERN LACKING OF HEAT AND HUMIDITY. GOING DEEPER...SLIGHTLY NEGATIVE NAO/AO INDICES INTO THE EARLY-HALF OF AUGUST AS THE ENSEMBLE SPREAD OF THE PNA EXHIBITS AN OVERALL POSITIVE TREND SIGNALS CONTINUED RIDGING OVER THE E-PACIFIC WITH PREFERRED TROUGHING E. NO SURPRISE THAT THE NAEFS/GEFS ANALOGS ALONG WITH THE EC-ENSEMBLE HOLD A BUCKLED PATTERN ACROSS THE REGION AS THE W-ATLANTIC RIDGE REMAINS STOUT. TREND OF ANOMALOUS BELOW-NORMAL CONDITIONS PREVAILS. THOUGH...PER AFOREMENTIONED ANALOGS/ENSEMBLES...THERE IS A POTENTIAL TREND TOWARDS DEAMPLIFICATION. THIS RESONATES WITHIN GLOBAL FORECAST SOLUTIONS HIGHLIGHTING A PHASE-SHIFT IN THE MJO CLIMATOLOGICALLY RESULTING IN A MORE ZONAL PATTERN WITH WARMER TEMPERATURE ANOMALIES OVER NORTH AMERICA. SOME UNCERTAINTY WITH A CONTINUED LOW ANOMALY OVER NE CANADA. WILL HAVE TO WAIT AND SEE. AS TO THE FORECAST...WILL TREND WITH MORE SEASONABLE CONDITIONS AS CYCLONIC FLOW ALOFT PREVAILS USHERING MUCH COOLER AIR S OUT OF CANADA. PRECIPITATION CHANCES VARY...BUT WILL NEED TO CLOSELY MONITOR INDIVIDUAL IMPULSES AND ACCOMPANYING JET STREAKS THROUGH THE OVERALL TROUGH PATTERN. ITS PLAUSIBLE TO SEE PERIODS OF WET WEATHER SHOULD THE TROUGH WOBBLE PARENT WITH ITS NEIGHBORING RIDGE AXES. WILL BREAK DOWN THE HIGHLIGHTS/CONFIDENCE WITHIN THE DAILY DISCUSSION BELOW. */ DAY-TO-DAY DETAILS... WEDNESDAY... MID- TO UPPER-LEVEL CYCLONIC FLOW USHERS +8-10C H85 AIR INTO S NEW ENGLAND AS THE MAJORITY OF ACTIVITY/DYNAMICS IS SHUNTED OFFSHORE. WEAK HIGH PRESSURE WITH LIGHT WINDS SLOWLY TURNING S TOWARDS THE END OF THE PERIOD. LOTS OF DRY AIR IN PLACE AS IT CONTINUALLY WRAPS INTO THE OCCLUSION AS NEW ENGLAND FINDS ITSELF WITHIN THE LFQ OF THE UPPER-LEVEL JET...A FAVORABLE REGION OF SUBSIDENCE. WILL PREVAIL WITH SEASONABLE CONDITIONS WITH SEA-BREEZES ALONG THE SHORES. A DRY FORECAST WITH ACTIVITY HELD WELL N/W PARENT WITH THE OCCLUSION AND BETTER COLD-POOL. PARTLY CLOUDY CONDITIONS DURING THE DAY WITH DIURNAL CUMULUS. THURSDAY... MAIN IMPULSE ASSOCIATED WITH THE OCCLUSION EJECTS CYCLONICALLY OVER THE E GREAT LAKES. EXPECT SUBSEQUENT FALLING HEIGHTS COLLOCATED WITH STRONG ENHANCED ASCENT AND DEEP-LAYER LIFT /ESPECIALLY WITHIN THE LFQ OF AN ATTENDANT JET STREAK/. SHOULD SEE DIURNALLY-DRIVEN ACTIVITY DEVELOP ACROSS INTERIOR NEW ENGLAND BENEATH COOLER AIR ALOFT AND CYCLONIC FLOW. SEVERITY SHOULD BE LIMITED LACK OF INSTABILITY WITH POOR LAPSE RATES AND ABUNDANCE OF DRY AIR...DESPITE DECENT SW-NE UNI-DIRECTIONAL SHEAR. EXPECT ISOLATED TO SCATTERED ACTIVITY AWAY FROM THE SHORELINES WHICH SHOULD REMAIN FAIRLY QUIET UNDER THE INFLUENCE OF ONSHORE MARITIME AIR. FRIDAY INTO SATURDAY... PACIFIC-ORIGIN ENERGY ROUNDING THE BROADER TROUGH PATTERN STREAMS NE ACROSS NEW ENGLAND. MID- TO UPPER-LEVEL TIGHTENING OF THE PRESSURE GRADIENT RESOLVES A FASTER JET STREAK SUBSEQUENTLY. SHOULD SEE A BROADSCALE REGION OF FAVORABLE ASCENT DEVELOP ACROSS NEW ENGLAND. BUT CHALLENGES PREVAIL BETWEEN LIKELY DIURNALLY DRIVEN ACTIVITY ACROSS INTERIOR NE-CONUS AND LINGERING OFFSHORE FRONTAL BOUNDARY. ANTICIPATING A REGION BETWEEN OF DRIER WEATHER...JUST WHERE AND HOW IT EVOLVES ENTERTAINS A FAIR AMOUNT OF UNCERTAINTY. EC/GEFS TREND WITH ACTIVITY MAINLY ACROSS THE INTERIOR WHEREAS THE 27.12Z GFS RETROGRADES THE OFFSHORE FRONT PARENT WITH A FRONTAL LOW CONSEQUENTIAL OF THE AFOREMENTIONED PACIFIC ENERGY. ALL SOLUTIONS SHOW THE MAIN LOW OVER THE GREAT LAKES LIFTING OUT OF THE REGION TO THE NE. SUNDAY INTO EARLY NEXT WEEK... THOUGH PATTERN DEAMPLIFICATION IS POSSIBLE...CYCLONIC FLOW PREVAILS BEHIND THE EARLIER PACIFIC IMPULSE. WILL HOLD WITH THE TYPICAL SUMMER-TIME PATTERN OF CONVECTION ACROSS THE INTERIOR WITH QUIET WEATHER ALONG THE SHORES.
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&& .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. LOW CONFIDENCE THROUGH 12Z...THEN MODERATE CONFIDENCE ON TRENDS BEYOND THAT. CONDITIONS LOWER TO IFR/LIFR THROUGH 12Z AS FOG/LOW CLOUDS BECOME MORE WIDESPREAD. AREA OF SHOWERS/STORMS LIFTING NE FROM NYC AREA WILL REACH CT VALLEY 06Z-08Z AND E MA COAST 08Z-10Z. POTENTIAL FOR GUSTY WINDS...HEAVY RAINFALL AND FREQUENT LIGHTNING. AS THIS ACTIVITY LIFTS INTO NORTHERN NEW ENGLAND BY EARLY AFTERNOON...MVFR CIGS PREVAIL BUT MANY AREAS SHOULD IMPROVE TO VFR BY 18Z. EXCEPTION IS ALONG S COAST WHERE IT WILL TAKE LONGER FOR LOWER CEILINGS TO LIFT. SCATTERED SHOWERS/STORMS SHOULD REDEVELOP ACROSS INTERIOR AFTER 18Z...MAINLY IN SW NH...WESTERN/CENTRAL MA AND N CT. IMPROVING CONDITIONS TO VFR AFTER 00Z TUE...ALTHOUGH PATCHY MVFR/IFR POSSIBLE IN FOG. VFR TUE WITH AFTERNOON SEA BREEZES. KBOS TAF...MODERATE CONFIDENCE. IFR CIGS/VSBYS DEVELOP AS SHOWERS/ISOLATED STORMS ARRIVE AFTER 08Z. FAIRLY CONFIDENT ON IMPROVING CONDITIONS AFTER 15Z. TS SHOULD REMAIN W OF AIRPORT 18Z-22Z. KBDL TAF...MODERATE CONFIDENCE. IFR CIGS/VSBYS DEVELOP AS SHOWERS/STORMS ARRIVE BY 08Z. FAIRLY CONFIDENT IN IMPROVING CONDITIONS AFTER 13Z. TS MOST LIKELY 18Z-22Z. OUTLOOK...WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE. WEDNESDAY...HIGH CONFIDENCE. VFR WITH LIGHT WINDS GRADUALLY TURNING S. SEA-BREEZES ALONG THE SHORES. THURSDAY...MODERATE CONFIDENCE. ISOLATED-SCATTERED SHRA/TSRA POSSIBLE OVER INTERIOR TERMINALS WITH MIX OF MVFR-IFR CONDITIONS. SEA-BREEZES ALONG THE SHORES. FRIDAY...LOW CONFIDENCE. SCATTERED-WIDESPREAD SHRA/TSRA. MAIN FOCUS ACROSS SE/W/CENTRAL NEW ENGLAND. COULD BE A LULL IN ACTIVITY AROUND THE BOS-PVD CORRIDOR.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH MON NIGHT TONIGHT...PATCHY DENSE FOG POSSIBLE. SHOWERS AND TSTMS REDEVELOP TOWARD DAYBREAK. A FEW STRONG STORMS POSSIBLE ALONG WITH VERY HEAVY RAIN. MONDAY...PATCHY DENSE FOG IN THE MORNING BURNS OFF/ERODES BY EARLY AFTERNOON. EARLY MORNING SHOWERS AND TSTMS TAPER OFF FOLLOWED BY A NEW ROUND OF SHOWERS/TSTMS MID TO LATE AFTERNOON. A FEW OF THESE STORMS MAY BE STRONG ALONG WITH HEAVY DOWNPOURS. SSW WINDS MAY APPROACH 25 KT AS THE AFTERNOON PROGRESSES ESPECIALLY NEAR SHORE. MON NIGHT...COLD FRONT SWEEPS ACROSS THE WATERS WITH A WIND SHIFT TO THE WNW ALONG WITH DRY WEATHER AND GOOD VSBY. OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE. TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. LIGHT WINDS ASSOCIATED WITH HIGH PRESSURE SHOULD ALLOW FOR TRANQUIL BOATING WEATHER AS SEAS DIMINISH. FRIDAY...MODERATE CONFIDENCE. WHILE BOATING CONDITIONS REMAIN TRANQUIL...WILL SEE INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS DEVELOP ACROSS THE WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 7 AM THIS MORNING TO 7 PM EDT THIS EVENING FOR ANZ235-250-254>256.
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&& $$ SYNOPSIS...NOCERA NEAR TERM...JWD SHORT TERM...NOCERA LONG TERM...SIPPRELL AVIATION...JWD MARINE...NOCERA/SIPPRELL

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