Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 011804 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 204 PM EDT FRI AUG 1 2014 .SYNOPSIS... SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. LOW PRESSURE WILL LIKELY BRING A PERIOD OF STEADY RAIN TO AT LEAST SOUTHEAST NEW ENGLAND ON SATURDAY WITH PERHAPS JUST A FEW SPOT SHOWERS AROUND ON SUNDAY. SEASONABLE WEATHER IS EXPECTED EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 130 PM UPDATE...SCATTERED SHOWERS AND ISOLATED TSTMS HAVE DEVELOPED ACROSS THE INTERIOR MORE OR LESS ALONG THE PATTERN ADVERTIZED BY THE HRRR. SUFFICIENT INSTABILITY AND WEAK SHORT WAVE TROF SEEN IN WATER VAPOR IMAGERY HELPING TO SET OFF THE SCATTERED CONVECTION. WIND SHEAR IS RELATIVELY LOW AND SO NOT TOO LIKELY TO SEE SEVERE...ALTHOUGH WILL NEED TO BE ON THE LOOKOUT FOR THE RISK OF A HIGHLY LOCALIZED PULSE STORM. AREA OF GREATEST INSTABILITY THIS AFTERNOON ANTICIPATED TO BE BOUNDED BY AREA ALONG AND TO RIGHT OF LWM-BED-IJD-HFD-BAF-ORE-AFN-MHT LINE. BRIEF HEAVY DOWNPOURS POSSIBLE WITH SOME STORMS. WITNESSED DUAL POL RAFL RATE UP TO 1.5 INCHES/HOUR WITH STORM THAT PASSED ACROSS HOLYOKE. TEMPS STILL LOOK ON TRACK FROM MID MORNING UPDATE EXCEPT WHERE LOCAL COOLING IN VICINITY OF CONVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... ***A PERIOD OF STEADY RAIN APPEARS LIKELY ON SATURDAY FOR AT LEAST THE SOUTHEAST NEW ENGLAND*** TONIGHT... ANY LEFT OVER SHOWERS/ISOLATED THUNDERSTORMS SHOULD DIMINISH EARLY THIS EVENING WITH THE LOSS OF DAYTIME HEATING. OTHERWISE...EXPECT MUCH OF THE NIGHT TO BE DRY WITH MORE PATCHY FOG DEVELOPING LATE IN THE TYPICALLY PRONE LOCATIONS. A WAVE OF LOW PRESSURE WORKING UP ALONG A STALLED BOUNDARY TO OUR EAST MAY ALLOW RAIN TO OVERSPREAD SOUTHERN SECTIONS TOWARDS DAYBREAK SATURDAY. SATURDAY... A WAVE OF LOW PRESSURE AND ITS ASSOCIATED TROPICAL MOISTURE WILL WORK NORTHWARD ALONG A STALLED BOUNDARY TO OUR EAST. GIVEN WEAK BAROCLINICITY THIS TIME OF YEAR...THE MODELS OFTEN STRUGGLE WITH THE PLACEMENT/TIMING OF PRECIPITATION SHIELDS. THIS CASE IS NO EXCEPTION...AS THE MODELS HAVE BEEN ALL OVER THE PLACE IN THE LAST 48 HOURS. WE DO THINK THAT AT LEAST SOUTHEAST SECTIONS WILL SEE A PERIOD OF STEADY RAIN WITH SOME SCATTERED SHOWERS FURTHER BACK INTO THE INTERIOR. PWATS WILL APPROACH 2 INCHES IN OUR SOUTHEAST SECTIONS...SO SOME LOCALLY HEAVY RAINFALL IS POSSIBLE ALONG PORTIONS OF THE SOUTHEAST NEW ENGLAND COAST. INSTABILITY IS VERY LIMITED...SO DID NOT INCLUDE ANY THUNDER IN THE FORECAST. ALL IN ALL...WE HAVE LOW CONFIDENCE IN THE LOCATION/TIMING OF THE RAIN SHIELD ON SATURDAY. HOWEVER...WE DO THINK AT LEAST THE SOUTHEAST NEW ENGLAND COAST WILL SEE A PERIOD OF STEADY RAIN WHICH MAY BE HEAVY FOR A TIME. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGHLIGHTS... * SHOWERS AND THUNDERSTORMS POSSIBLE EARLY NEXT WEEK THE MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE LONG TERM. HOWEVER...THERE ARE DEFINITELY DIFFERENCES BOTH IN THE DETAILS AND ALSO IN PARTS OF THE SYNOPTIC PATTERN...PARTICULARLY AROUND THE POTENTIAL SYSTEM FOR THE WEEKEND. USED A BLEND OF AVAILABLE GUIDANCE FOR MUCH OF THE FORECAST. SATURDAY NIGHT AND SUNDAY...A STATIONARY FRONT OFF THE COAST SHIFTS WEST OVER SOUTHERN NEW ENGLAND. COMBINED WITH AN INCREASE IN SUBTROPICAL MOISTURE...EXPECT A FAIRLY STEADY RAINFALL ACROSS AT LEAST A PORTION OF SOUTHERN NEW ENGLAND THROUGH PART OF THIS TIME. THERE ARE STILL DIFFERENCES IN THE MODELS BOTH IN THE WESTWARD EXTENT OF THE FRONT AND IN THE TIMING SO RAIN IS POSSIBLE THROUGHOUT THIS TIME PERIOD AND ACROSS THE REGION. HOWEVER...THE HIGHEST LIKELIHOOD FOR RAIN IS ALONG THE SOUTH COAST...RI...AND SE MA. THE NAM INDICATES ENOUGH INSTABILITY FOR SOME ISOLATED THUNDER...BUT IT IS ALONE IN FORECASTING THAT SO WILL LEAVE IT OUT FOR THE TIME BEING. MONDAY AND TUESDAY...STATIONARY FRONT SLOWLY SHIFTS BACK OFFSHORE BRINGING AN END TO THE STEADY RAINFALL. HOWEVER...LOW PRESSURE MOVING THROUGH QUEBEC WILL BRING A COLD FRONT TOWARDS SOUTHERN NEW ENGLAND. EXPECT THE POSSIBILITY FOR SHOWERS AND THUNDERSTORMS PERIODICALLY. WEDNESDAY AND THURSDAY...HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT. COOLER BUT QUIET WEATHER IS EXPECTED. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THIS AFTERNOON THROUGH SATURDAY... THIS AFTERNOON...MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS EXCEPT BRIEFLY LOWER IN VICINITY OF SCATTERED SHOWERS/TSTMS. SEA BREEZES ALONG THE COAST. TONIGHT...MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS EXCEPT PATCHY FOG IN THE TYPICALLY PRONE LOCATIONS LATE. SATURDAY...MODERATE CONFIDENCE. EXPECT A PERIOD OF FAIRLY STEADY RAIN ACROSS SOUTHERN AND EASTERN SECTIONS OF THE REGION WITH WIDESPREAD MVFR CIGS AND VSBYS. GENERALLY VFR ACROSS THE NW HALF OF THE AREA. KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS THIS AFTERNOON AND TONIGHT. MOST TSTM ACTIVITY SHOULD OCCUR NW OF THE AIRFIELD BUT A LOW PROBABILITY EXISTS OF ONE MOVING ACROSS THE AIR FIELD. EAST SOUTHEAST SEA BREEZE SHOULD PERSIST THROUGH THE AFTERNOON AND THEN SHIFT TO BE FROM SW AFTER ABOUT 00Z. NW EDGE OF RAIN SHIELD MAY BE CLOSE TO BOS LATE SAT MORNING AND AFTERNOON. KBDL TAF...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS THIS AFTERNOON EXCEPT POSSIBLY BRIEFLY LOWER IN VICINITY OF ANY TSTMS. VFR CONDITIONS EXPECTED TONIGHT EXCEPT THERE COULD BE A FEW HOURS OF MVFR VSBYS IN FOG...ESPECIALLY IF THE IMMEDIATE AREA IS AFFECTED BY ANY SHOWERS/TSTMS THIS AFTERNOON. VFR CONDITIONS EXPECTED AT OUTSET SAT BUT RAIN SHIELD MAY COME JUST FAR ENOUGH NORTH FOR MVFR CIGS AND VSBYS. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SATURDAY NIGHT THROUGH SUNDAY...MODERATE CONFIDENCE. MAINLY VFR NW...CHANCE FOR MVFR CIGS/VSBYS IN SCATTERED SHOWERS. MVFR CONDITIONS MORE PROBABLE TOWARDS EASTERN MA/RI IN -RA. MONDAY AND TUESDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR/IFR CONDITIONS IN SCT -SHRA/TSRA. COLD FRONT MOVES THROUGH SOUTHERN NEW ENGLAND TUESDAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TODAY THROUGH SATURDAY... HIGH CONFIDENCE. UPPER LEVEL RIDGING EAST OF THE WATERS WILL KEEP WINDS/SEAS BELOW SCA ADVISORY THRESHOLDS THROUGH SATURDAY AFTERNOON. VISIBILITIES WILL GENERALLY BE GOOD...BUT SOME REDUCTIONS ARE POSSIBLE ON SATURDAY ACROSS THE SOUTHERN AND EASTERN WATERS IN RAIN. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SATURDAY NIGHT AND SUNDAY...HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE WATERS. RAIN IS LIKELY THROUGH SUNDAY WITH A WAVERING STATIONARY FRONT NEAR OR OVER THE WATERS. VISIBILITIES ARE LIKELY TO BE REDUCED IN FOG. MONDAY AND TUESDAY...HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. COLD FRONT MOVES OVER THE WATERS LATE TUESDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/RLG/THOMPSON NEAR TERM...FRANK/RLG/THOMPSON SHORT TERM...FRANK LONG TERM...RLG AVIATION...FRANK/RLG/THOMPSON MARINE...FRANK/RLG

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