664  
FXUS61 KBOX 180207  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
1007 PM EDT WED OCT 17 2018  
   
SYNOPSIS
 
 
A COLD FRONT MOVED ACROSS THE REGION THIS EVENING. WINDY  
CONDITIONS AND THE COLDEST AIR OF THE SEASON WILL FOLLOW  
TONIGHT AND THURSDAY. SCATTERED SHOWERS THIS WEEKEND. BREEZY  
AND MILD AHEAD OF A COLD FRONT SATURDAY, THEN RATHER WINDY AND  
COLDER SUNDAY. ANOTHER CHANCE OF SHOWERS TUESDAY AND WEDNESDAY.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
* UNSEASONABLY COLD OVERNIGHT WITH STRONG WINDS AFTER MIDNIGHT  
 
1005 PM UPDATE...  
 
PREVIOUS FORECAST ON TRACK. THE BRIEF BURST OF STRONG TO LOCALLY  
DAMAGING WIND GUSTS EARLIER TODAY WITH THE INITIAL COLD  
FRONT HAVE DIMINISHED. A SECONDARY COLD FRONT/SHORTWAVE WAS  
APPROACHING THE REGION LATE THIS EVENING. A FEW BRIEF SPOT  
SHOWERS OR EVEN HIGH TERRAIN WET SNOW FLAKES MAY ACCOMPANY THIS  
FRONT.  
 
OTHERWISE...THE MAIN STORY WILL BE A SECOND SURGE OF STRONG  
WINDS DEVELOPING AFTER MIDNIGHT. THIS WILL BE ASSOCIATED WITH A  
PULSE OF 40 TO 45 KNOTS OF WINDS AT 850 MB WITH THE ASSOCIATED  
SHORTWAVE. BASED ON MODEL SOUNDINGS AND STEEP LAPSE RATES...A  
GOOD PORTION OF THESE WINDS SHOULD MIX DOWN FOR A TIME.  
THEREFORE...CONTINUING WIND ADVISORY FOR MA & RI AFTER MIDNIGHT  
INTO EARLY THURSDAY MORNING. THE CONCERN IS WITH THE POTENTIAL  
FOR GUSTS UP TO 45 MPH...FULLY LEAFED TREES WILL BE MORE  
SUSCEPTIBLE TO DAMAGE THAN WE OFTEN SEE LATER IN THE FALL AND  
INTO THE WINTER. THEREFORE...THE RISK FOR ISOLATED TREE  
DAMAGE/POWER OUTAGES CONTINUE OVERNIGHT.  
 
LOW TEMPERATURES BY DAYBREAK WILL BOTTOM OUT IN THE UPPER 20S TO  
THE MIDDLE 30S. FREEZE WARNINGS CONTINUE FOR NORTHERN  
CT/NORTHWEST RI AND PORTIONS OF MA WHERE THE GROWING SEASON HAS  
NOT OFFICIALLY ENDED. STRONG WINDS WILL RESULT IN WIND CHILL  
VALUES IN THE UPPER TEENS TO THE MIDDLE 20S BY DAYBREAK.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/
 
 
THURSDAY...  
 
BLUSTERY AND UNSEASONABLY COLD DAY FOR THIS TIME OF YEAR,  
ALTHOUGH WITH PLENTY OF SUNSHINE. HIGHS WILL BE IN THE LOWER 40S  
HIGHER TERRAIN AND MID/UPPER 40S ELSEWHERE WHICH IS MORE TYPICAL  
OF LATE NOVEMBER TO EARLY DECEMBER. NW GUSTS TO 25-40 MPH IN  
THE MORNING WILL DIMINISH IN THE AFTERNOON. THIS WIND WILL ADD  
TO THE CHILL.  
 
THURSDAY NIGHT...  
 
HIGH PRES BUILDS SOUTH OF NEW ENG WITH RIDGING EXTENDING INTO  
THE REGION. MAINLY CLEAR SKIES AND DIMINISHING WIND WILL RESULT  
IN ANOTHER COLD NIGHT WITH MANY LOCATIONS AWAY FROM THE COAST  
DROPPING TO 25-30 DEGREES. MILDEST READINGS IN THE LOW TO MID  
30S WILL BE CONFINED TO EAST COASTAL MA, AREAS NEAR  
NARRAGANSETT BAY AND CAPE/ISLANDS.  
 

 
   
LONG TERM /FRIDAY THROUGH WEDNESDAY/
 
 
HIGHLIGHTS...  
 
* MAINLY DRY THROUGH THE PERIOD WITH TEMPERATURES A TAD BELOW NORMAL  
* GUSTY WINDS POSSIBLE BEHIND COLD FRONT SATURDAY NIGHT AND  
SUNDAY  
 
OVERVIEW...  
 
A DEEP UPPER LEVEL TROUGH WILL APPROACH FROM THE WEST ON SATURDAY  
THEN RESIDE OVER SOUTHERN NEW ENGLAND ON SUNDAY. AT THE SURFACE, A  
COLD FRONT WILL MOVE THROUGH LATE SATURDAY, BUT THE MAIN SURGE OF  
COLD AIR AND GUSTY WINDS TAKES PLACE HERE ON SUNDAY. THE UPPER  
TROUGH SLIDES EAST MONDAY WITH ANOTHER UPPER TROUGH APPROACHING  
AROUND MID-WEEK...GFS IS FASTER AND ECMWF IS MUCH SLOWER.  
 
DAILIES...  
 
FRIDAY...AFTER A CHILLY START, SOUTHWEST WINDS KICK IN AS HIGH  
PRESSURE SLIDES OFF THE MID-ATLANTIC COAST AND A COLD FRONT MOVES  
THROUGH THE GREAT LAKES REGION. MAINLY SUNNY SKIES, BUT INCREASING  
HIGH CLOUDS FROM THE WEST TOWARD EVENING. HIGHS REACHING THE UPPER  
50S. BECOMING CLOUDY FRIDAY NIGHT WITH A SLIGHT CHANCE OF A SHOWER  
AFTER MIDNIGHT. NOT AS COLD AS THURSDAY NIGHT, WITH LOWS IN THE 40S,  
EXCEPT LOWER 50S CAPE COD AND ISLANDS.  
 
SATURDAY...BREEZY AND MILD SOUTHWEST FLOW AHEAD OF A COLD FRONT.  
MOSTLY CLOUDY SKIES WITH A CHANCE OF SOME SHOWERS. HIGHS IN THE  
UPPER 50S TO LOWER 60S. WINDS SHIFT TO THE NORTHWEST BEHIND THE  
FRONT SATURDAY NIGHT. PARTIAL CLEARING AND TURNING COLDER WITH LOWS  
IN THE 30S WEST AND LOWER 40S EAST.  
 
SUNDAY...WITH THE UPPER TROUGH OVERHEAD, SKIES WILL BE VARIABLY  
CLOUDY WITH A FEW SHOWERS AROUND, ESPECIALLY IN EASTERN SECTIONS.  
A STRONG SURGE OF COLD ADVECTION WILL BLAST THROUGH, WITH 850 MB  
TEMPERATURES DROPPING TO -8C TO -9C. GOOD MIXING WILL LEAD TO  
NORTHWEST WINDS GUSTING UP TO 25-30 MPH AT TIMES. GALE FORCE GUSTS  
POSSIBLE OVER THE COASTAL WATERS. HIGH TEMPERATURES ONLY REACH THE  
MID TO UPPER 40S EXCEPT LOWER 50S CAPE COD AND ISLANDS. LOWS SUNDAY  
NIGHT MID 20S NW TO MID 30S SE.  
 
MONDAY...MAINLY SUNNY AND COOL WITH HIGHS IN THE 40S.  
 
TUESDAY AND WEDNESDAY...SOME TIMING DIFFERENCES EXIST AMONGST MODELS  
AS TO APPROACH OF UPPER TROUGH AND SURFACE COLD FRONT. IN GENERAL,  
BECOMING MOSTLY CLOUDY WITH SCATTERED SHOWERS POSSIBLE  
BOTH DAYS. HIGHS UPPER 40S TO MID 50S.  
 

 
   
AVIATION /02Z THURSDAY THROUGH MONDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.  
 
TONIGHT... VFR. W/NW WIND GUSTS 15-30 KT WITH A PULSE OF 30-40  
KT NW GUSTS AFTER 06Z. A FEW BRIEF SPOT SHOWERS OR EVEN WET SNOW  
FLAKES ARE POSSIBLE IN THE HIGH TERRAIN THROUGH ABOUT 6Z.  
 
THURSDAY...  
VFR. NW WIND GUSTS 25-35 KT IN THE MORNING DIMINISHING IN THE  
AFTERNOON.  
 
THURSDAY NIGHT...  
VFR. WINDS BECOMING LIGHT.  
 
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.  
 
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.  
 
OUTLOOK /FRIDAY THROUGH MONDAY/...MODERATE-HIGH CONFIDENCE.  
 
FRIDAY: VFR. BREEZY.  
 
FRIDAY NIGHT THROUGH SATURDAY: VFR. WINDY WITH GUSTS TO 30 KT.  
SLIGHT CHANCE SHRA.  
 
SATURDAY NIGHT: VFR. BREEZY.  
 
SUNDAY THROUGH SUNDAY NIGHT: VFR. WINDY WITH GUSTS TO 35 KT.  
 
MONDAY: VFR. BREEZY.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.  
 
GALE WARNINGS WILL REMAIN IN EFFECT FOR ALL WATERS INTO THU.  
WEST GUSTS 25-35 KT INTO THIS EVENING, THEN A SURGE OF NW WIND  
GUSTS TO 35-40 KT EXPECTED AFTER MIDNIGHT INTO THU MORNING  
BEHIND A DEPARTING SHORTWAVE. WINDS GRADUALLY DIMINISH THU  
AFTERNOON INTO THE EVENING WITH GUSTS BELOW 20 KT BY LATE THU  
NIGHT.  
 
OUTLOOK /FRIDAY THROUGH MONDAY/...MODERATE TO HIGH  
 
FRIDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 25 KT. AREAS OF SEAS APPROACHING 5 FT.  
 
FRIDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS. SLIGHT CHANCE OF RAIN  
SHOWERS.  
 
SATURDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 35 KT.  
AREAS OF ROUGH SEAS. SLIGHT CHANCE OF RAIN SHOWERS.  
 
SATURDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 25 KT. LOCAL ROUGH SEAS. SLIGHT CHANCE OF RAIN  
SHOWERS.  
 
SUNDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 35 KT.  
AREAS OF ROUGH SEAS. SLIGHT CHANCE OF RAIN SHOWERS.  
 
SUNDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. LOCAL ROUGH SEAS.  
 
MONDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.  
 

 
   
CLIMATE
 
 
RECORD LOW MAXIMUM TEMPERATURES FOR THURSDAY OCTOBER 18  
 
BOS 45 IN 1898  
ORH 36 IN 1989  
BDL 44 IN 2009  
PVD 46 IN 1939  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...FREEZE WARNING FROM 3 AM TO 9 AM EDT THURSDAY FOR CTZ002>004.  
MA...WIND ADVISORY UNTIL 8 AM EDT THURSDAY FOR MAZ002>004-008>012-  
017>021-023.  
WIND ADVISORY UNTIL 10 AM EDT THURSDAY FOR MAZ005>007-013>016-  
026.  
FREEZE WARNING FROM 3 AM TO 9 AM EDT THURSDAY FOR MAZ005-006-  
009>013.  
WIND ADVISORY UNTIL 10 AM EDT THURSDAY FOR MAZ022-024.  
RI...WIND ADVISORY UNTIL 8 AM EDT THURSDAY FOR RIZ001>008.  
FREEZE WARNING FROM 3 AM TO 9 AM EDT THURSDAY FOR RIZ001.  
MARINE...GALE WARNING UNTIL 2 PM EDT THURSDAY FOR ANZ231-232-251.  
GALE WARNING UNTIL 10 AM EDT THURSDAY FOR ANZ233-234.  
GALE WARNING UNTIL 10 AM EDT THURSDAY FOR ANZ230-236.  
GALE WARNING UNTIL 11 AM EDT THURSDAY FOR ANZ235-237.  
GALE WARNING UNTIL 4 PM EDT THURSDAY FOR ANZ250-254>256.  
 

 
 

 
SYNOPSIS...KJC/GAF  
NEAR TERM...FRANK  
SHORT TERM...KJC  
LONG TERM...GAF  
AVIATION...KJC/GAF  
MARINE...KJC/GAF  
CLIMATE...STAFF  
 
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