Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 171413 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1013 AM EDT SUN AUG 17 2014 .SYNOPSIS...
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SCATTERED LIGHT RAIN SHOWERS REGIONWIDE AND POSSIBLY AN ISOLATED THUNDERSTORM OVER SOUTHEAST MASSACHUSETTS WILL BE THE THEME TODAY. A COLD FRONT SWEEPS ACROSS THE AREA THIS EVENING WITH DRIER CONDITIONS RETURNING TO THE AREA THROUGH THE MIDDLE OF THE WEEK. UNSETTLED WEATHER NOW APPEARS TO SLIDE SOUTH OF NEW ENGLAND MID TO LATE NEXT WEEK...YIELDING MAINLY DRY WEATHER TO SOUTHERN NEW ENGLAND.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1015 AM UPDATE...SEEING A FEW SHOWERS MOVING INTO RHODE ISLAND...BUT MOSTLY DRY WEATHER ACROSS THE REGION. MADE MINOR UPDATES TO THE SKY GRIDS TO BETTER ILLUSTRATE THE LATEST TRENDS. OTHERWISE THE FORECAST IS ON TRACK. 700 AM UPDATE... OVERALL TREND OF THE FORECAST IS ON TRACK THIS MORNING. HAVE ADJUSTED POPS JUST SLIGHTLY THIS AFTERNOON IN INCREASE THE CHANCE WHEN THE FRONT PASSES THROUGH. STILL LOOKS LIKE A FEW ISOLATED T-STORMS ARE POSSIBLE. OTHERWISE PATCHY GROUND FOG THIS MORNING WILL BURN OFF IN THE NEXT HOUR OR TWO. PREVIOUS DISCUSSION... IMPRESSIVE NORTHERN SHORT WAVE TROUGH AND ASSOCIATED JET STREAK MOVING ACROSS THE NORTHEAST EARLY THIS MORNING. HOWEVER MID LEVEL DRY AIR AND LACK OF INSTABILITY ARE LIMITING THE PRECIP TO WIDELY SCATTERED LIGHT LOW TOP RAIN SHOWERS/SPRINKLES. WILL HAVE TO WATCH AREA OF HIGHER DEW PT/THETA-E AIRMASS AND ASSOCIATED INSTABILITY SOUTH OF NEW ENGLAND. APPROACHING TROUGH MAY BE ABLE TO CAPTURE/ADVECT THIS INSTABILITY NORTHWARD ACROSS SOUTHEAST MA AND POSSIBLY INTO NORTHEAST MA AND RI. THIS MAY BE SUFFICIENT FOR SHOWERS TO BECOME SOMEWHAT MORE WIDESPREAD ONCE SURFACE HEATING COMMENCES ALONG WITH A LOW RISK OF AN ISOLATED T-STORM. STRONG DEEP LAYER SHEAR OVER SOUTHEAST MA WITH VALUES AROUND 35 KT...HOWEVER GIVEN NO MORE THAN A FEW HUNDRED JOULES OF CAPE ARE AVAILABLE ANY CONVECTION SHOULD BE ISOLATED AND NOT STRONG. FARTHER TO THE WEST ACROSS CT/WEST-CENTRAL MA INTO SOUTHWEST NH LESS INSTABILITY AND SURFACE CONVERGENCE WILL RESULT IN LESS SHOWER ACTIVITY ACROSS THIS REGION THIS AFTERNOON. IN ADDITION COLD FRONT AND POST FRONTAL AIRMASS WILL LIKELY OVERSPREAD THIS REGION LATER THIS MORNING INTO THE EARLY AFTERNOON...SHIFTING THE FOCUS OF SHOWERS TO EASTERN MA AND RI. HENCE MAINLY DRY CONDITIONS THIS AFTERNOON ACROSS CT/WEST-CENTRAL MA AND SOUTHWEST NH. IT WILL FEEL LIKE A SUMMER DAY GIVEN THE MILD START THIS MORNING COMBINED WEAK LOW LEVEL WARM ADVECTION AHEAD OF APPROACHING TROUGH. ALSO DEW PTS WILL BE MODERATELY HIGH WITH VALUES IN THE L60S...HIGHEST DEW PTS OVER RI AND SOUTHEAST MA. HIGHS SHOULD TOP OUT IN THE L80S WITH MU70S ALONG THE SOUTH COAST AND ACROSS THE HIGHER TERRAIN. IT WILL BECOME BREEZY ACROSS SOUTHEAST MA AS SOUTHWEST WINDS INCREASE TO 15 TO 20 MPH THIS AFTERNOON.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... TONIGHT... FAIRLY ROBUST COOL AIR ADVECTION /BY MID TO LATE AUG STANDARDS/ BEHIND DEPARTING FRONT AS CLOSED LOW SLIDES SOUTHEAST FROM QUEBEC INTO NEW BRUNSWICK. 850 TEMPS COOL DOWN TO +9C BY 12Z OVER THE SOUTHERN NEW ENGLAND. MONDAY... SECOND/TRAILING SHORT WAVE MOVES ACROSS THE AREA DURING THE MORNING. THIS FEATURE WILL COME THRU THE REGION DRY BUT WILL PROVIDE A REINFORCING SURGE OF DRY/LESS HUMID AIRMASS INTO SOUTHERN NEW ENGLAND. CORE OF COLD POOL ALOFT IS WELL NORTHEAST OF NEW ENGLAND ACROSS THE MARITIMES...SO DIURNAL CU SHOULD BE LIMITED TO SCT TO PERHAPS BROKEN AT TIMES YIELDING AT LEAST PARTIAL SUNSHINE. OVERALL A REAL NICE DAY WITH LOW HUMIDITY...LIGHT WINDS AND MILD TEMPS...ALBEIT A FEW DEGS COOLER THAN NORMAL. SEABREEZES ARE POSSIBLE ESPECIALLY EASTERN MA COASTLINE. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... HIGHLIGHTS... * DRY WEATHER AND NORMAL TEMPS ON TUES/WED * DIURNAL SHOWERS POSSIBLE AT THE END OF THE WEEK * BELOW AVERAGE TEMPS OVER NEXT WEEKEND OVERVIEW... MODELS ARE IN GENERALLY GOOD AGREEMENT FOR THE MEDIUM TO LONG RANGE. BLOCKINESS OVER ATLANTIC CANADA AND GREENLAND ALLOW FOR THE `BERMUDA HIGH` AND SOUTHEAST RIDGE TO BUILD WESTWARD INTO THE SOUTHEAST QUARTER OF THE NATION...AND A SPLIT-FLOW PATTERN TO DEVELOP EAST AND NORTH OF THE MISSOURI VALLEY. BY THE END OF THE PERIOD...AN MORE AMPLIFIED PATTERN WILL PERSIST AS STRONG HIGH PRESSURE BUILDS ACROSS THE CENTRAL CONUS AND TROUGHING DIPS BACK INTO THE NORTHEAST. DETAILS... TUESDAY INTO WEDNESDAY AM... GUIDANCE CONTINUES TO SHOW A SHORTWAVE MOVING FROM THE GREAT LAKES EASTWARD. BECAUSE OF THE SIGNIFICANT GREENLAND BLOCK...APPEARS THAT THE SYSTEM WILL REMAIN TO THE SOUTH OF NEW ENGLAND AND IMPACT THE MID-ATLANTIC. THE PRECIP SHIELD COULD REACH THE SOUTHERN WATERS AND PERHAPS THE SOUTH COAST...SO KEPT LINGERING SLIGHT CHC POPS IN FOR NOW. TEMPERATURES WILL BE NEAR NORMAL AS UPPER LEVEL RIDGING MOVES OVER THE REGION. WEDNESDAY AFTERNOON AND THURSDAY... ZONAL FLOW ALOFT WILL ALLOW FOR SEASONABLE TEMPS TO RETURN TO THE REGION. WEAK HIGH PRESSURE ON WED WILL SHIFT EASTWARD. ALTHOUGH THERE ARE DIFFERENCES IN TIMING...APPEARS A SHORTWAVE WILL MOVE THROUGH THE FLOW. THIS WAVE MAY SPARK SOME SHOWERS AND T-STORMS BY THE END OF THE WORK WEEK. FRIDAY AND BEYOND... FIRST GLANCE LOOK LIKE AN UPPER LEVEL TROUGH DIGS WELL SOUTH OF SOUTHERN NEW ENGLAND. THIS MAY ALLOW FOR COLD CORE SYSTEMS OR PERHAPS A BACK DOOR COLD FRONT. REGARDLESS HAVE TRENDED THE TEMPS BELOW AVERAGE FOR THIS TIME FRAME. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THROUGH MONDAY... AFTER 12Z...VFR WITH LIGHT SCATTERED RAIN SHOWERS. AFTER 18Z ANY SHOWERS WILL BE CONFINED TO RI AND EASTERN MA. LOW RISK OF A FEW -TSRA AND MVFR CONDITIONS OVER SOUTHEAST MA...POSSIBLY INTO RI AND NORTHEAST MA. COLD FRONT BEGINS TO EXIT THE REGION AROUND 23Z AND ENDING THE THREAT OF SHOWERS/ISOLATED T-STORM. TONIGHT...VFR AND DRY WEATHER ALONG WITH A LIGHT NW WIND. MONDAY....VFR AND DRY WEATHER. AFTERNOON SEABREEZES POSSIBLE EASTERN MA COASTLINE INCLUDING LOGAN. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SCATTERED LIGHT RAIN LOW TOP SHOWERS UNTIL ABOUT 21Z. LOW RISK OF ISOLATED T-STORM SOUTH OF LOGAN ACROSS SOUTHEAST MA. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...TUESDAY THROUGH THURSDAY... TUESDAY...MODERATE CONFIDENCE. VFR. MAY SEE LOCAL MVFR CONDITIONS ACROSS THE SOUTH COAST IN SCT SHOWERS. WEDNESDAY...HIGH CONFIDENCE. VFR. THURSDAY...MODERATE CONFIDENCE. VFR EXCEPT FOR ANY DIURNAL SHOWERS WHERE MVFR IS POSSIBLE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TODAY...SW WIND 10 TO 15 KT WITH GUSTS UP TO 20 KT VICINITY OF CAPE COD AND THE ISLANDS. SCATTERED LIGHT RAIN SHOWERS WITH A LOW RISK OF AN ISOLATED TSTM. TONIGHT...COLD FRONT SWEEPS ACROSS THE WATERS THIS EVENING WITH WINDS SHIFTING FROM SW TO WNW 10 TO 15 KT WITH A FEW GUSTS UP TO 20 KT POSSIBLE. MONDAY...QUIET WEATHER AS HIGH PRES BUILDS FROM SOUTHEAST CANADA INTO NEW ENGLAND. OUTLOOK...TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. TUESDAY NIGHT INTO THURSDAY... LOW PRESSURE SYSTEM WILL SLOWLY SLIDE ACROSS THE WATERS. THIS WILL ALLOW FOR SEAS AND WIND GUSTS TO INCREASE. LOW CONFIDENCE ON IF WE WILL REACH 5 FT SEAS OR 25 KTS. FOR NOW APPEARS THAT WE WILL BE JUST SHY...NEAR 20 KTS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/DUNTEN NEAR TERM...NOCERA/DUNTEN SHORT TERM...NOCERA LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN

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