Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 221126 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 726 AM EDT FRI AUG 22 2014 .SYNOPSIS... THE THREAT FOR SHOWERS WILL CONTINUE...ESPECIALLY ACROSS THE WEST THROUGH TONIGHT. DRIER AND COOLER WEATHER FOLLOWS THIS WEEKEND. A WARM-UP IS POSSIBLE NEXT WEEK PRIOR TO AN UNSETTLED PATTERN AHEAD OF A FRONTAL BOUNDARY SWEEPING SOUTH OUT OF CANADA. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 725 AM UPDATE... LATEST RUNS OF THE HRRR APPEAR TO HAVE A GOOD HANDLE ON THE SHOWERS THIS MORNING...AT LEAST IN TERMS OF THE OVERALL TRENDS. AS SUCH...USED THE HRRR TO TWEAK POPS FOR THIS MORNING. ALSO TWEAKED TEMPERATURES AND DEW POINTS TO REFLECT THE LATEST OBSERVED TRENDS. PREVIOUS DISCUSSION... SHOWERS CONTINUE TO DEVELOP IN-SITU THIS MORNING ACROSS THE REGION AS THE FIRST OF A SERIES OF VORT-MAX/S MOVES THROUGH THE REGION EARLY THIS MORNING. PWATS ARE MARGINAL /AROUND TO JUST BELOW 1.5 INCHES/ WITH K-VALES IN THE W ABOUT 30-32. THEREFORE...SUSPECT THIS THREAT FOR -SHRA TO CONTINUE THROUGH THE MORNING. ESPECIALLY WERE WEAK CONVERGENT BOUNDARIES ARE ALLOWED TO FORM IN THE RELATIVELY WEAK NEAR SFC FLOW. WILL CARRY POPS THROUGH MID DAY MAINLY W OF THE WORCESTER HILLS INTO SRN NH...BUT WOULD NOT BE SURPRISED TO SEE A FEW SHOWERS MAKE IT INTO THE BOS-PVD CORRIDOR. OTHERWISE TODAY...THIS FIRST VORT MAX IS EXPECTED TO JOIN FORCES WITH CUTOFF LOW PRES STALLED IN BLOCKING FLOW ACROSS ATLANTIC CANADA...FORMING A HANGING TROF WHOSE BASE WILL REST TO THE S OF REGION. NOTE THAT AS THIS TROF DEVELOPS AND A SERIES OF WEAKER WAVES ROTATE THROUGH...HEIGHTS CONTINUE DECLINE INTO THE OVERNIGHT HOURS. OVERALL COLUMN MOISTURE DOES ACTUALLY DIMINISH THROUGH THE DAY...CLOSER TO BETWEEN 1.0-1.25 INCHES AND OVERALL INSTABILITY /INCLUDING K-VALUES/ DIMINISH THROUGH THE DAY AS WELL. GIVEN THIS...AND THE FACT THAT ANOTHER AXIS OF SFC BASED INSTABILITY REMAINS TO THE W IN NY THANKS TO WHAT IS LIKELY TO BE MORE CLEAR SKIES...AND CONTINUED MARINE INFLUENCE THANKS TO E COMPONENT TO THE FLOW SUSPECT CONVECTIVE ACTIVITY TO ONCE AGAIN FIRE MAINLY W OF NEW ENGLAND THIS AFTERNOON AND EVENING. THIS MAY ACTUALLY USURP SOME OF THE AVAILABLE MOISTURE...SO WILL ACTUALLY HIGHLIGHT DECLINING POPS THROUGH THE AFTERNOON...EXCEPT IN THE DUE TO REMNANT CONVECTION ADVECTING E. AS MENTIONED...EXPECT A LOT MORE WIDESPREAD CLOUD COVER TODAY THANKS TO MARINE INFLUENCE AND COOLING TEMPS ALOFT. THEREFORE...HIGHS MAY STRUGGLE TO MAKE IT OUT OF THE 60S IN SPOTS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... TONIGHT... AM NOTING SIMILAR SETUP AS THU NIGHT. ANOTHER WEAK SHORTWAVE WILL PUSH N-S ACROSS THE REGION AND PHASE WITH OFFSHORE LONGWAVE TROF CONNECTED TO CUTOFF IN ATLANTIC CANADA. TWO CONDITIONS ARE DIFFERENT HOWEVER...PWATS ARE A BIT LOWER /1.0-1.25 INCHES AS OPPOSED TO 1.5/ AND K INDEX VALUES ARE LOWER AS DRIER AIR INTRUDES THROUGH THE COLUMN FROM THE TOP DOWN. THEREFORE...SAVE FOR THE ADVECTION OF LEFTOVER CONVECTION FROM THE W...SUSPECT THAT -SHRA ARE LIKELY TO BE A BIT WEAKER AND LESS WIDESPREAD THAN THU NIGHT. HOWEVER...WILL STILL MAINTAIN AT LEAST CHANCE POPS ESPECIALLY FOR W AND NW PORTIONS OF THE FORECAST AREA. ONE OTHER ISSUE IS FOG AND/OR LOW CIGS MOVING INTO E PORTIONS OF THE FORECAST AREA. GUIDANCE CONTINUES TO NOTE AN AREA OF MOISTURE BACKING IN FROM THE GULF OF MAINE OVERNIGHT THANKS TO CONTINUED ELY COMPONENT OF THE FLOW. DO NOTE IN BUFKIT PROFILES THAT THERE IS A LAYER OF DRY AIR ABOVE THE SFC WHICH MAY NEGATE FOG DEVELOPMENT...ESPECIALLY IF STRATUS BACKS IN...LIMITING RADIATIVE PROCESSES. THEREFORE...WILL MAINLY MENTION LOW CLOUDS...BUT MAY NEED TO MONITOR FOR DRIZZLE WITH DRIER MOVING IN OVER MOISTURE POOLING IN THE LOW-MID LVLS. SHOULD SOME AREAS RADIATE...FOG REMAINS A RISK. SAT... ONE LAST PARTING SHOT FOR SHOWERS SAT AS SHORTWAVE ENERGY FORCES SOME DIGGING AND SOUTHWARD PROGRESSION OF THE OFFSHORE LONGWAVE TROF. LEFTOVER MOISTURE COMBINED WITH COOLING TEMPS ALOFT ARE LIKELY TO LEAD TO A FAIR AMOUNT OF CLOUD COVER DURING THE EARLY HALF OF THE DAY...ALONG WITH SHOWERS ESPECIALLY FROM PORTIONS OF THE MERRIMACK VALLEY E AND POINTS SE. HOWEVER...IMPROVEMENT BY THE AFTERNOON LOOKS POSSIBLE THANKS TO GRADUALLY RISING HEIGHTS FROM THE S SHIFT IN THE TROF. THIS WILL ALLOW SFC INVERTED RIDGING TO GRADUALLY REGAIN CONTROL ACROSS THE REGION TOWARD EVENING. IN FACT...DESPITE THE CLOUDY START TO THE DAY...ITS POSSIBLE MANY LOCATIONS STILL GET TO SEE THE SUNSET /EVEN IN THE E WHICH WILL LIKELY TAKE THE LONGEST TO BREAK OUT/. HIGHS REMAIN ON THE COOL SIDE OF NORMAL THANKS TO THE EARLY CLOUD COVER LIMITING DIURNAL INFLUENCE. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGHLIGHTS... * QUIET WEATHER EXPECTED THROUGH MUCH OF THIS PERIOD * UNCERTAINTY INCREASES MIDDLE OF NEXT WEEK WITH AN APPROACHING FRONT 21/00Z MODELS ARE IN GOOD AGREEMENT THROUGH ABOUT TUESDAY. THEN SIGNIFICANT DIFFERENCES ARISE FOR THE LATTER HALF OF NEXT WEEK... MAKING FOR A LOWER CONFIDENCE FORECAST FROM THE MIDDLE OF NEXT WEEK ONWARD. A PERSISTENT UPPER LEVEL TROUGH OVER THE NORTHEAST WILL SLOWLY MAKE ITS WAY EAST...MOVING JUST OFFSHORE THIS WEEKEND AS AN UPPER LEVEL RIDGE TRIES TO PUSH NORTHEASTWARD FROM THE SOUTHERN USA. THIS UPPER TROUGH IS RATHER PERSISTENT THOUGH...WITH EACH SUCCESSIVE MODEL RUN LINGERING THIS TROUGH OVER THE NORTH ATLANTIC LONGER AND LONGER. COOLER...LESS SEASONABLE WEATHER IS EXPECTED WHILE HIGH PRESSURE IN QUEBEC WILL KEEP THINGS RELATIVELY DRY. STILL AGREE WITH THE PREVIOUS FORECASTER...THINKING 21/00Z GUIDANCE CONTINUES TO STRUGGLE WITH CONVECTIVE FEEDBACK INTO EARLY NEXT WEEK. AS SUCH...KEPT A DRY FORECAST ACROSS MOST OF SOUTHERN NEW ENGLAND. A HIGH PRESSURE WILL SINK SOUTH INTO EARLY NEXT WEEK...EVENTUALLY MOVING SOUTH AND EAST OF SOUTHERN NEW ENGLAND AND RETURNING US TO A MORE WESTERLY FLOW. A LOW PRESSURE IN ONTARIO MAY EVENTUALLY MOVE EAST INTO QUEBEC...SWINGING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND WEDNESDAY OR THURSDAY. THIS IS WHERE MODELS START TO DIVERGE MORE SIGNIFICANTLY. THE ECMWF LOOKS A BIT QUICKER THAN THE GFS WITH THE APPROACH OF THIS FRONT...BUT NEITHER IS AS PROGRESSIVE AS THE CANADIAN. WILL TAKE A BLENDED APPROACH WITH THE TIMING FOR NOW. GIVEN THE STRENGTH OF THE SURFACE RIDGE EXPECTED TO BE NEAR THE COAST...WOULD NOT BE OVERLY SURPRISED IF THE ULTIMATE TIMING TURNS OUT TO BE SLOWER THAN THE GFS. DEPENDING ON AVAILABLE MOISTURE...WE COULD SEE SOME SHOWERS AND THUNDERSTORMS AHEAD OF THIS FRONT. && .AVIATION /11Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THROUGH SATURDAY...MODERATE CONFIDENCE. TODAY INTO TONIGHT... CONDITIONS IMPROVE TO VFR MOST LOCATIONS THROUGH THE DAY... ALTHOUGH LOW VFR CIGS ARE LIKELY ESPECIALLY AREAS W OF THE WORCESTER HILLS. SHOWERS LINGER IN THIS REGION AS WELL. BY TONIGHT...SHOWERS DISSIPATE BUT THERE MAY BE MORE WIDESPREAD FOG IN THE W AND THE POSSIBILITY OF LOWER CIGS IN THE E. THEREFORE...COMPLEX OVERNIGHT SCENARIO...WHERE SOME OCCASIONAL MVFR/IFR CONDITIONS ARE POSSIBLE. SAT... CONDITIONS IMPROVE TO VFR ALL LOCATIONS EXCEPT MAYBE AREAS E OF THE WST-ORH-AFN...WHERE SOME MVFR CONDITIONS MAY LINGER INTO THE DAY IN LOW CIGS. BY AFTERNOON...LIKELY TO SEE VFR ALL LOCATIONS. KBOS TERMINAL...MODERATE CONFIDENCE. MAINLY VFR TODAY EXCEPT FOR OCCASIONAL SHOWERS AND MVFR THIS MORNING. OVERNIGHT...EASTERLY FLOW COULD YIELD A PERIOD OF LOW CLOUDS WITH MVFR/IFR CIGS POSSIBLE. SHOULD THESE BE ESTABLISHED...ITS POSSIBLE THEY LINGER INTO THE MORNING HOURS SAT. KBDL TERMINAL...MODERATE CONFIDENCE. MVFR/VFR MAY BOUNCE BACK AND FORTH THROUGH THE MORNING WITH SHOWERS. BY AFTERNOON...CONDITIONS IMPROVE TO VFR AND MAY STAY THAT WAY THEREAFTER. OUTLOOK...SATURDAY THROUGH TUESDAY... HIGH CONFIDENCE VFR. LOW PROBABILITY OF PATCHY MVFR/IFR FOG EACH NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM...THROUGH SATURDAY...HIGH CONFIDENCE. E TO NE FLOW WILL CONTINUE INTO SAT AS HIGH PRES TO THE NE SLOWLY REGAINS CONTROL. THROUGH THE DAY TODAY AND NIGHT TONIGHT...PERIODS OF WIND GUSTS OF 15-20 KT ARE POSSIBLE AT TIMES WITH A SLOWLY BUILDING SWELL. SEAS SHOULD REMAIN BELOW 4 FT EVEN ON THE SE AND S WATERS. THEREFORE...NO SMALL CRAFT HEADLINES. SOME FOG AND SHOWERS ARE POSSIBLE ON THE WATERS AT TIMES AS WELL...MAINLY THIS MORNING...AND ONCE AGAIN OVERNIGHT. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... HIGH CONFIDENCE. HIGH CONFIDENCE. QUIET BOATING WEATHER IS EXPECTED FOR MUCH OF THIS PERIOD WITH HIGH PRESSURE ACROSS THE REGION. SEAS COULD APPROACH 5 FT ACROSS THE OUTERMOST SOUTHERN COASTAL WATERS THIS WEEKEND. NOT ENOUGH CONFIDENCE TO ISSUE A SMALL CRAFT ADVISORY THOUGH. LOW PROBABILITY OF PATCHY OVERNIGHT FOG LIMITING VISIBILITIES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/DOODY NEAR TERM...BELK/DOODY SHORT TERM...DOODY LONG TERM...BELK AVIATION...BELK/DOODY MARINE...BELK/DOODY

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