Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 011858 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 258 PM EDT TUE SEP 1 2015 .SYNOPSIS... HOT AND HUMID WEATHER PREVAILS BENEATH HIGH PRESSURE TOWARDS THURSDAY BY WHICH TIME A COLD FRONT SHOULD BRING SCATTERED SHOWERS AND THUNDERSTORMS FOR MUCH OF THE REGION. THEN NOT AS WARM AND NOTICEABLY LESS HUMID WEATHER FRIDAY INTO SAT MORNING. A WARMING TREND FOLLOWS FOR THE HOLIDAY WEEKEND WITH TEMPERATURES WELL INTO THE 80S TO PERHAPS NEAR 90 BY SUNDAY AND MONDAY ALONG WITH DRY WEATHER. && .NEAR TERM /THROUGH 6 AM WEDNESDAY/... MID-LEVEL RIDGING PREVALENT BENEATH WHICH WINDS WILL BE LIGHT OVER- NIGHT. STOUT DRY-SUBSIDENCE INVERSION IN PLACE YIELDS THE POTENTIAL FOR SURFACE MOISTURE-POOLING. LOOKING AT A LOW-CLOUD / FOG POTENTIAL AS THE COMBINATION OF LIGHT WINDS AND MOSTLY CLEAR CONDITIONS NET AN ENVIRONMENT FAVORABLE FOR RADIATIONAL COOLING. GOT A FEW DEGREES COOLER INTO TUESDAY MORNING THAN INITIALLY THOUGHT...SO WILL GO A DEGREE OR TWO COOLER THAN MOS WITH LOWS AROUND THE LOW-60S AND A HIGHER FOG POTENTIAL ACROSS THE INTERIOR. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... WEDNESDAY... CERTAINLY HOT AND HUMID WITH SEVERAL LOCALES SEEING TEMPERATURES INTO THE LOW-90S BENEATH INFLUENTIAL MID-LEVEL RIDGING AND DRY-AIR SUBSIDENCE AND A H85 AIRMASS ALOFT OF +18-20C. A MOSTLY CLEAR DAY WITH SOME SCATTERED CUMULUS OUT TO THE W PARENT WITH INCREASING LOW- TO MID-LEVEL THETAE. ECHOING THE PREVIOUS FORECASTER...MOISTURE AND INSTABILITY APPEAR INTERESTING BENEATH FAVORABLE LAPSE RATES MORE TO THE N. BUT ABSENT ARE THE FORCING MECHANISMS. BUFKIT PROFILES SHOW A STRONG WARM-DRY CAP AROUND H85 WITH PARENT DEEP-LAYER SUBSIDENCE. SO LOOKING TO REMAIN DRY. LIGHT WINDS OVERALL WITH SEA-BREEZES ALONG THE SHORES. WEDNESDAY NIGHT... NOTEWORTHY MID-ATLANTIC LOW PUSHING E AND OFFSHORE TO OUR S AS A COLD FRONT APPROACHES FROM THE N. LOOK TO BE IN THE SQUEEZE-PLAY OF THE TWO WITH MORE DOMINANT SUBSIDENCE AND DRY AIR ASSOCIATED WITH RIDGING OF LINGERING HIGH PRESSURE. WILL KEEP WITH A DRY FORECAST WITH LIGHT WINDS. ANOTHER NIGHT OF LOW CLOUDS / PATCHY DENSE FOG IS POSSIBLE AS MOISTURE POOLS AGAIN BENEATH A DECOUPLING BOUNDARY-LAYER AND DRY-SUBSIDENCE INVERSION. OTHERWISE INCREASING MID-HIGH LEVEL CLOUDS WORKING IN TOWARDS MORNING. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGHLIGHTS... * SCATTERED T-STORMS THU...OTHERWISE DRY WEATHER PREVAILS * COOLER AND LESS HUMID THU NIGHT/FRI INTO SAT MORNING * DRY WITH A GRADUAL WARMING TREND FOR THE HOLIDAY WEEKEND WED NIGHT...QUIET/DRY WEATHER WITH RIDGING HOLDING ON AND ASSOCIATED DEEP LAYER DRY AIR OVER THE REGION. IT WILL BE A WARM NIGHT AFTER DAYTIME TEMPS WED PEAK IN THE U80S AND L90S. THIS COMBINED WITH DEW PTS REMAINING IN THE 60S WILL RESULT IN MINS ONLY FALLING TO 65 TO 70...WITH LOW 70S IN THE URBAN AREAS. THURSDAY...BEST CHANCE FOR A BRIEF END TO OUR DRY WEATHER AS MID LEVEL TROUGH MOVES ACROSS THE MARITIMES AND DRAGS A COLD FRONT ACROSS SNE. BEST SYNOPTIC SCALE FORCING IS DISPLACED WELL EAST OF NEW ENGLAND...HOWEVER SHALLOW LIFT/CONVERGENCE ASSOCIATED WITH THE FRONT WILL COMBINE WITH MODEST DEEP LAYER MOISTURE TO YIELD A RISK FOR SCATTERED SHOWERS/T-STORMS. MODERATE INSTABILITY WITH PROJECTED CAPES ON THE ORDER OF 1000-2000J/KG. HOWEVER LIMITING FACTOR IS LACK OF DEEP LAYER SHEAR. THUS CONVECTION WILL BE DIFFICULT TO SUSTAIN AND THIS WILL REDUCE THE THREAT OF STRONG TO SEVERE STORMS. HOWEVER IF CAPES CAN GROW TO 2000 J/KG OR GREATER INSTABILITY MAY COMPENSATE FOR LACK OF DEEP LAYER SHEAR WITH THE RISK OF A FEW STORMS BECOMING STRONG TO PERHAPS SEVERE. ALTHOUGH WEAK WIND FIELDS ALOFT SUGGEST ONLY A LOW RISK OF STRONG STORMS. PWATS CLIMB TO ABOUT +1 STD DEVIATIONS GREATER THAN CLIMO. THIS COMBINED WITH WEAK WIND FIELDS ALOFT MAY POSE A LOW RISK OF SLOW MOVING STORMS AND ASSOCIATED FLOOD THREAT. OTHERWISE EXPECT ANOTHER VERY WARM AND HUMID DAY WITH HIGHS 85 TO 90. SO BY NO MEANS A WASHOUT OUT...A TYPICAL LATE SUMMER DAY WITH VERY WARM TEMPS AND A THREAT OF SCT AFTN/EVENING T-STORMS. THURSDAY NIGHT/FRIDAY/FRI NIGHT...NOTICEABLE AIRMASS CHANGE WITH COOLER AND LESS HUMID AIRMASS ADVECTS INTO THE REGION THU NIGHT AS 1027 MB CANADIAN HIGH BUILDS SOUTHWARD THRU QUEBEC. IN FACT COULD SEE NE WINDS GUSTS UP TO 20-25 MPH OVER SE MA FRI MORNING! ALTHOUGH THIS BACKDOOR COLD FRONT WON/T HAVE THE SAME PUNCH/COOL DOWN AS AN EARLY SUMMER/LATE SPRING EVENT AS SSTS IN GULF OF ME AND EASTERN MA WATERS ARE RUNNING 65-70! NEVERTHELESS REFRESHING CHANGE FRI INTO SAT AM AS 1027 HIGH BUILDS OVER THE AREA WITH DEW PTS IN THE 50S. THUS BREEZY NE WINDS FRI AM WILL SLACKEN IN THE AFTN. THIS WILL SET THE STAGE FOR A COOL FRI NIGHT WITH MINS EARLY SAT MORNING IN THE 50S REGIONWIDE...EXCEPT NEAR 60 IN THE URBAN AREAS AND ALONG THE COAST. HOLIDAY WEEKEND...AFTER A COOL/COMFORTABLE SAT MORNING A GRADUAL WARMING TREND AS MID LEVEL RIDGE BUILDS OVER THE AREA...RESULTING IN SURFACE RIDGE SLIDING SOUTH OF NEW ENGLAND YIELDING A WESTERLY SURFACE FLOW. THIS WEST WIND SHOULD KEEP HUMIDITY IN CHECK WITH DEW PTS LIKELY REMAINING IN THE 50S AND ONLY CREEPING UPWARD TOWARD 60 GIVEN DOWNSLOPE COMPONENT OF SFC WND. THUS EARLY INDICATIONS SUGGEST A DRY HOLIDAY WEEKEND WITH A GRADUAL WARMING TREND. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE. VFR. ONSHORE FLOW DIMINISHES OVERNIGHT. LIGHT WINDS AND SKC ALLOW FOR IFR FOG DEVELOPMENT IN SHELTERED / LOW-LYING TERMINALS ACROSS INTERIOR NEW ENGLAND. BURNING OFF DURING THE MORNING...LIGHT W/SW- FLOW RETURNS WITH SEA-BREEZES ALONG THE SHORES FOR WEDNESDAY. SCT 5 KFT CIGS TO THE W. A RETURN OF MVFR-IFR CIGS / VSBYS FOR THE WEDNESDAY OVERNIGHT PERIOD INTO THURSDAY MORNING. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE POSSIBLE ALBEIT LATER FOR WEDNESDAY. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...HIGH CONFIDENCE. MAINLY VFR CONDITIONS THROUGHOUT THE PERIOD. LOW PROBABILITY OF BRIEF MVFR CONDITIONS IN SCT SHRA/TSRA THU. ALSO...IFR VSBYS POSSIBLE IN PATCHY 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 WEDNESDAY NIGHT/...HIGH CONFIDENCE. SEAS AT OR BELOW 4-FEET. ONLY ISSUES ARE W/SW-WINDS OVER THE WATERS WITH GUSTS UP TO AROUND 15 KTS ACROSS THE E-OUTER WATERS FOR A MAJORITY OF THE PERIOD...PERHAPS SOME PATCHY DENSE FOG ALONG THE SHORES WITH ONSHORE FLOW DURING THE DAY. MAINLY QUIET BOATING WEATHER PREVAILS THROUGH WED. OUTLOOK /WEDNESDAY THROUGH SATURDAY/...HIGH CONFIDENCE. FAIRLY TRANQUIL BOATING WEATHER THIS PERIOD. THE EXCEPTION WILL BE LATE THU NIGHT INTO FRI MORNING WHEN 1027 MB HIGH OVER QUEBEC YIELDS A STIFF NE WIND OF 15 TO 20 KT WITH GUSTS UP TO 25 KT POSSIBLE. WINDS DROP OFF LATE FRI HOWEVER LOW PRES MAY DEVELOP WELL SE OF NOVA SCOTIA NEXT WEEKEND. THIS MAY RESULT IN EASTERLY SWELLS IMPACTING THE EASTERN MA WATERS. DRY WEATHER MUCH OF THE PERIOD WITH THE EXCEPTION OF SCATTERED T-STORMS POSSIBLE THU AFTN AND EVENING. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...NOCERA AVIATION...NOCERA/SIPPRELL MARINE...NOCERA/SIPPRELL

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.