Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 021805 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 205 PM EDT TUE JUN 2 2015 .SYNOPSIS...
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STALLED FRONT SOUTH OF NEW ENGLAND WILL KEEP UNSEASONABLY COOL AND WET CONDITIONS IN PLACE THIS AFTERNOON. HIGH PRESSURE RETURNS WITH DRIER WEATHER TOINGHT THROUGH MUCH OF THURSDAY. SHOWERS ARE POSSIBLE THURSDAY NIGHT INTO FRIDAY...AS ANOTHER COLD FRONT MOVES THROUGH THEN HIGH PRESSURE FOLLOWS FOR LATER SATURDAY INTO SUNDAY.
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&& .NEAR TERM /UNTIL 8 PM THIS EVENING/...
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2 PM UPDATE... RAIN SHIELD CONTINUING TO MAKE GOOD PROGRESS EASTWARD. SECOND BATCH OVER NORTHEAST PA INTO NORTHERN NJ AND LOWER HUDSON VALLEY. HOWEVER MID LEVEL DRY AIR IN THE 850-700 LAYER ADVECTING SOUTHEAST FROM NY STATE IS ERODING THE NORTHERN EDGE OF THIS RAIN SHIELD. THUS RADAR LOOKS MORE THREATENING THAN REALITY WITH RAIN STILL NOT REACHING THE GROUND AT POU DESPITE MODEST RETURNS OVERHEAD FROM KENX AND KOKX RADARS. THUS THIS BAND OF RAIN IS LIKELY TO DODGE NORTHERN CT-NORTHERN RI AND MUCH OF SOUTHEAST MA...WITH RAIN BAND LIKELY CONFINED TO THE SOUTH COAST. 6 HRS INTO THE 12Z MODEL RUNS THE 12Z NAM APPEARS TO BE VERIFYING BEST WHEN COMPARED TO SURFACE OBSERVATIONS...WITH THE 12Z GFS THE WORST. THUS WILL FOLLOW A NON-GFS SOLUTION FOR THE REMAINDER OF THIS AFTERNOON AND EVENING. AS THE RAIN ENDS WILL SEE TEMPS CLIMB FROM THE U40S INTO THE LOW AND MID 50S. STILL WELL BELOW NORMAL FOR EARLY JUNE!
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&& .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT... THE UPPER SHORTWAVE MOVES THROUGH AND OFF TO THE EAST. THIS WILL TURN THE UPPER FLOW NORTHWEST AND PUSH THE LAST OF THE PCPN OFFSHORE. WE EXPECT AT LEAST PARTIAL CLEARING FROM NORTHWEST TO SOUTHEAST DURING THE NIGHT. WITH DEW POINTS IN THE 40S...MIN TEMPS SHOULD ALSO BE IN THE 40S. WEDNESDAY... HIGH TEMPERATURES TODAY RUNNING ABOUT 20-25 DEGS BELOW NORMAL! NORMAL HIGH TODAY IS 70-75. HIGH PRESSURE OVER EASTERN CANADA BUILDS OVER NEW ENGLAND WITH DRY AIR/SUNSHINE. BUT THE SURFACE FLOW AROUND THE HIGH WILL DRAW WINDS BACK AROUND OUT OF THE NORTHEAST OFF THE WATER. WITH THE WIND COMING OFF WATER TEMPS IN THE LOWER 50S...THIS NATURAL AIR CONDITIONING SHOULD KEEP COASTAL TEMPERATURES IN EASTERN MASS AROUND 60...POSSIBLY JUST IN THE UPPER 50S. MEANWHILE THE CT VALLEY WILL BE LESS INHIBITED BY THE MARINE AIR AND SHOULD MIX TO AT LEAST 900 MB. TEMPS AT THE TOP OF THAT LAYER WOULD SUPPORT MAX TEMPS NEAR 70. HIGH TEMPERATURES TODAY RUNNING ABOUT 20-25 DEGS BELOW NORMAL! NORMAL HIGH TODAY IS 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * MAINLY DRY WITH BELOW NORMAL TEMPS THU * A FEW SHOWERS POSSIBLE FRI INTO SAT AS A COLD FRONT APPROACHES * DRY AND SEASONABLE SUN THEN THREAT OF SHOWERS RETURNS MON OVERVIEW AND MODEL PREFERENCES... ALTHOUGH THE 02/00Z MODEL GUIDANCE SUITE IS IN RELATIVELY GOOD AGREEMENT THROUGH THE WEEKEND...AT LEAST REGARDING THE UPPER LVL FLOW PATTERN...THERE SOME SPATIAL/TEMPORAL DIFFERENCES IN THE SFC/LOW LVL FEATURES WHICH WILL ULTIMATELY DRIVE SENSIBLE WX FRI- SUN. SPLIT FLOW REGIME ACROSS NA WITH THE WEAKER SRN STREAM DOMINATING INITIALLY. SLOW MOVING APPALACHIAN TROF LIES ON THE ERN EDGE OF MODERATE BLOCK THROUGH THE S CENTRAL CONUS. THIS BLOCK WILL FAVOR RIDGING ACROSS NEW ENGLAND THROUGH THE LATTER HALF OF THE WEEK. BY THE WEEKEND HOWEVER...THERE IS SOME SUGGESTION THAT A NRN STREAM WAVE MAY PHASE SOMEWHAT WITH THE WEAKER SRN STREAM TROF IN THE MID ATLANTIC. THIS IS WHERE CERTAINTY IN THE FORECAST DECREASES SOMEWHAT. MODELS ARE CONTINUING TO INDICATE A WEAK LOW LVL BAROCLINIC WAVE MOVING OFF THE MID ATLANTIC ON FRI...WHICH MAY ALLOW FOR THE FORCING OF SOME SHOWERS ACROSS THE REGION AS MOISTURE INCREASES. MODELS NOW INDICATING A LITTLE MORE QPF FRI THAN PREVIOUS RUNS SO WILL NEED TO CONTINUE TO MONITOR THIS TREND. THIS ALSO LEADS TO TIMING DIFFERENCES OF A COLD FROPA FOR SAT...BUT IN EITHER CASE...RISK FOR SHOWERS REMAINS UNTIL REMNANTS OF THE CENTRAL CONUS BLOCK ENHANCE RIDGING ONCE AGAIN ACROSS THE NE. DETAILS... WED NIGHT INTO THU... HIGH PRES REMAINS IN CONTROL BUT WILL BEGIN TO SLIP BACK TO THE E THROUGH THE PERIOD. EXPECTING MAINLY DRY WX...AND EVEN THOUGH SOME MODELS SUGGEST QPF LATE THU AND THU NIGHT...FEEL THE FORECAST IS MORE DRY THAN WET GIVEN BUFKIT DATA FROM THE SAME MODEL SHOWS DRY SUBSIDENCE INVERSION REMAINS IN PLACE. MODEL QPF MAY BE AN INDICATION OF THE STRUGGLE WITH THE WEAK BAROCLINIC WAVE DEVELOPMENT OFFSHORE LATE IN THE PERIOD. TEMPS ARE LIKELY TO REMAIN NEAR OR EVEN POSSIBLY SLIGHTLY BELOW SEASONAL NORMALS AS H85 TEMPS ARE GENERALLY BELOW +10C. FRI AND SAT... GRADUALLY DEEPENING NRN STREAM SHORTWAVE COMBINES WITH LEFTOVER ENERGY FROM AN APPALACHIAN WAVE TO INCREASE PRECIPITATION CHANCES THROUGH THIS PERIOD THANKS TO TWO PRIMARY MECHANISMS. 1. A WEAK OFFSHORE LOW PRES SYSTEM MOVING WELL S OF THE REGION...BUT FORCING AN INVERTED TROF ACROSS SRN NEW ENGLAND AND 2. A COLD FRONTAL PASSAGE. PWATS PEAK LATE FRI AND FRI NIGHT...JUST ABOVE 1.50 INCHES /ABOUT 1.5 STD DEVIATIONS ABOVE NORMAL. THEREFORE...EXPECT A PERIOD WITH PRECIPITATION CHANCES. NOT A WASHOUT HERE AS FORCING IS RELATIVELY WEAK...AND THE COLUMN SOMEWHAT STABLE. SLIGHT-CHANCE POPS STILL LOOK REASONABLE. TEMPERATURES REMAIN NEAR SEASONAL NORMALS IN SPITE OF RETURN FLOW. MAINLY DUE TO THE EXPECTATION OF MORE CLOUD COVER THAN THU. SUN... RETURN TO BRIEF RIDING AS REMNANTS OF THE CENTRAL CONUS BLOCK MOVES ACROSS THE AREA BEHIND THE COLD FRONT WHICH IS LIKELY TO STALL OFFSHORE. TEMPS MAINLY JUST BELOW NORMAL DUE TO H85 TEMPS PROGGED BELOW +10C. EARLY NEXT WEEK... ANOTHER POSSIBLE THREAT FOR RAINFALL AS A MORE ROBUST NRN STREAM SHORTWAVE IS PROGGED TO DIVE S FROM QUEBEC/ONTARIO. FINAL OUTCOMES ARE LIKELY TO BE DEPENDENT ON TIMING/INSTABILITY BUT GIVEN THERE IS A CONNECTION TO GULF MOISTURE WITH THIS DEEPER WAVE...ENSEMBLES SUPPORT PWATS APPROACHING 2 STD DEVIATIONS ABOVE NORMAL. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 2 PM UPDATE... THRU 00Z... RAIN SHIELD CONTINUES TO ADVANCED EASTWARD. RAIN OVER NORTHEAST PA...NORTHERN NJ INTO SOUTHEAST NY STATE WILL TRACK ESE AND BE CONFINED TO THE SOUTH COAST OF CT/RI AND SOUTHEAST MA. MAINLY MVFR CONDITIONS WILL DOMINATE WITH A TREND TOWARD VFR. MODERATE TO HIGH FORECAST CONFIDENCE. AFTER 00Z... GRADUAL IMPROVEMENT EXPECTED WITH RAIN EXITING THE SOUTH COAST AROUND 00Z. HOWEVER NOT EXPECTING A CLEAN POST FRONTAL AIRMASS WITH SOME PATCHY MVFR CIGS POSSIBLE. LOW CONFIDENCE ON EXACT AREAL COVERAGE. WEDNESDAY... LOW PROB OF PATCHY LINGERING MVFR CIGS IN THE MORNING BUT ALL TERMINALS VFR BY 15Z. NORTH WINDS TREND NORTHEAST BY AFTERNOON ESPECIALLY ALONG THE COAST. HIGH FORECAST CONFIDENCE. WED NIGHT... VFR WITH A LOW PROB OF MVFR IN PATCHY FOG ACROSS WESTERN MA LATE. KBOS TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS BUT LOWER IN EXACT TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS BUT LOWER IN EXACT TIMING. OUTLOOK...THURSDAY THROUGH SATURDAY... THU INTO FRI...HIGH CONFIDENCE. MAINLY VFR. ALTHOUGH OCCASIONAL MVFR/IFR POSSIBLE IN FOG/SHRA FRI NIGHT. THIS WILL BE HIT-OR-MISS. WINDS MAINLY SOUTHERLY. SAT...HIGH CONFIDENCE. MAINLY VFR WITH SOME SHOWERS. WINDS SHIFT FROM S TO NNW.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY NIGHT/...MODERATE TO HIGH CONFIDENCE. TODAY...NORTHEAST WINDS AROUND 15 KNOTS SUSTAINED AND WITH GUSTS UP TO 25 KNOTS. THIS SHOULD MAINTAIN 5-6 FOOT SEAS ON MASS BAY AND THE ADJACENT OUTER WATERS...WITH SLIGHTLY LOWER SEAS WEST AND SOUTH. SHOWERS WILL CONTINUE TO MOVE NORTHEAST UP THE COAST ACROSS THE WATERS...WITH SOME LOCALLY HEAVY DOWNPOURS POSSIBLE. LOW RISK OF ISOLATED THUNDER. TONIGHT...HIGH PRESSURE BUILDS FROM THE NORTH. WINDS SHOULD DIMINISH AND BECOME NORTHERLY. SEAS MAY LINGER AROUND 5 FEET ON THE OUTER WATERS. WEDNESDAY...WINDS SHIFT TO EAST-NORTHEAST BUT WITH SPEEDS UNDER 15 KNOTS. SEAS WILL ALSO DIMINISH TO 4 FEET OR LOWER. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... THU INTO EARLY FRI...HIGH CONFIDENCE. WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT THRESHOLDS AS HIGH PRES MOVES OVER THE WATERS. LATE FRI INTO SAT...MODERATE CONFIDENCE. LOW PRES PASSING WELL TO THE S AND AN APPROACHING COLD FRONT WILL LEAD TO INCREASED CHANCES FOR PRECIP/FOG OVER THE WATERS AT TIMES. S WINDS WILL GIVE WAY TO NW WINDS LATE SAT. SOME WIND GUSTS MAY APPROACH 20-25 KT MAINLY SAT. SEAS HOWEVER...SHOULD GENERALLY REMAIN BELOW THE 5 FT MARK. && .CLIMATE... RECORD LOW MAX TEMPS FOR TODAY... BOS...50...1946 BDL...50...1907 (RECORD FOR THE MONTH) PVD...47...1907 (RECORD FOR THE MONTH) ORH...47...1946 (RECORD FOR THE MONTH) && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230>235-237-250-251-255-256. SMALL CRAFT ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR ANZ254. && $$ SYNOPSIS...WTB/DOODY NEAR TERM...NOCERA SHORT TERM...WTB LONG TERM...DOODY AVIATION...NOCERA/DOODY MARINE...WTB/DOODY CLIMATE...

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