269  
FXUS61 KBOX 221130  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
630 AM EST SUN DEC 22 2024  
   
SYNOPSIS
 
 
BLUSTERY AND VERY COLD TODAY WITH WIND CHILLS ONLY RECOVERING INTO  
THE SINGLE NUMBERS AND TEENS. WINDS DROP OFF TONIGHT AND MONDAY AS  
HIGH PRESSURE BUILDS INTO THE REGION, BUT VERY COLD CONDITIONS WILL  
CONTINUE. A WEAK CLIPPER SYSTEM MAY BRING VERY MINOR SNOW  
ACCUMULATIONS LATE MONDAY NIGHT INTO CHRISTMAS EVE MORNING.  
OTHERWISE, DRY WEATHER DOMINATES THE REST OF THE HOLIDAY WEEK WITH  
TEMPERATURES MODERATING BACK TO SEASONABLE LEVELS.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
UPDATED: 3:30 AM  
 
KEY MESSAGES:  
 
* VERY COLD AND DRY CONDITIONS FOR TODAY.  
 
* OCEAN EFFECT SNOW SHOWERS MAY LEAD TO PERIODS OF FESTIVE FLURRIES  
ACROSS THE OUTER CAPE THIS AFTERNOON AND EVENING.  
 
WELL, WINTER OFFICIALLY ARRIVED YESTERDAY MORNING AND DID NOT TAKE  
LONG TO UNPACK AND GET SETTLED. IT IS DOWN RIGHT COLD THIS MORNING  
AS AN ARCTIC AREA OF HIGH PRESSURE BUILDS IN TO THE WEST ACROSS THE  
GREAT LAKES. EARLY MORNING TEMPERATURES ARE EXPECTED TO BE IN THE  
SINGLE DIGITS FOR MANY, WITH THE URBAN CENTERS AND IMMEDIATE COAST  
IN THE LOWER TEENS. BUT, WHEN YOU FACTOR IN THE NORTHWEST WIND IT  
WILL FEEL MUCH COLDER, SUB-ZERO WIND CHILLS. AREAS IN FAR WESTERN  
MASSACHUSETTS, BERKSHIRE COUNTY ARE UNDER A COLD WEATHER ADVISORY  
THIS MORNING DUE TO WIDESPREAD WIND CHILL VALUES AT LEAST 15 BELOW  
ZERO. MUCH OF OUR AREA WILL EXPERIENCE WIND CHILL VALUES 5 TO 10  
DEGREES BELOW ZERO, WITH ISOLATED SPOTS ALONG THE BORDER WITH  
BERKSHIRE COUNTY 10 TO 15 BELOW ZERO.  
 
THERE WILL BE LITTLE IMPROVEMENT THIS AFTERNOON AS THE HIGH NUDGES  
CLOSER TO SOUTHERN NEW ENGLAND. EXPECT A WELL-MIXED BOUNDARY LAYER,  
MIXING BETWEEN 950MB AND 900MB, WILL BE ABLE TO TRANSFER DOWN GUSTY  
NORTHWEST WINDS BETWEEN 15 AND 25 MPH THROUGH LATE MORNING, EASING  
WINDS THIS AFTERNOON AND TONIGHT. 925MB TEMPERATURES -20C TO -16C  
RESULT IN HIGH TEMPERATURES IN THE TEENS AND LOW 20S NEAR THE COAST.  
THESE TEMPERATURES ARE NEARING RECORD COLDEST HIGHS IN PLACES LIKE  
BOSTON, WHERE THE RECORDED LOWEST HIGH FOR TODAY IS 17F, OUR CURRENT  
FORECAST CALLS FOR A HIGH OF 19F. WILL INCLUDE MORE DETAILS ON  
RECORD LOWEST HIGHS IN THE CLIMATE SECTION OF THE AFD. LASTLY, THE  
WIND CHILL REMAINS SUB-ZERO THROUGH AT LEAST MID MORNING WITH MINOR  
IMPROVEMENTS TO THE SINGLE DIGITS LATER THIS AFTERNOON.  
 
WHILE IT IS FRIGID, THERE WILL BE PLENTY OF SUNSHINE ACROSS MUCH OF  
THE REGION, WITH THE EXCEPTION OF CAPE COD AND THE ISLANDS. WITH A  
PERSISTENT NNW WIND DIRECTION, AN ARCTIC AIRMASS OVER RELATIVELY  
WARM SSTS IN THE 40S, OCEAN EFFECT SNOW STREAMERS ARE POSSIBLE TODAY  
AND INTO THE EVENING. THESE FEATURES CAN BE TOUGH TO PIN DOWN,  
HAVE OPT TO LEAVE 'CHANCE' POPS OVER MOST OF THE OUTER CAPE FOR  
TODAY AND THEN 'SLIGHT CHANCE' THIS EVENING. PWATS ARE 0.1"  
THIS AFTERNOON SO THERE IS NOT MUCH MOISTURE TO TAP INTO, BUT  
FESTIVE SNOW SHOWERS COULD LEAD TO A COATING, WITH THE WORST  
CASE SCENARIO UP TO AN INCH FOR THE OUTER CAPE THROUGH TONIGHT.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/
 
 
UPDATED: 3:30 AM  
 
KEY MESSAGES:  
 
* VERY COLD TONIGHT WITH TEMPERATURES BETWEEN 10F AND -5F! STILL  
COLD ON MONDAY, BUT SLIGHTLY 'WARMER' THAN SUNDAY.  
 
NO CHANGE IN THE AIRMASS FOR TONIGHT WITH SPRAWLING HIGH PRESSURE TO  
THE WEST, WILL HAVE EASING WINDS AND CLEAR SKIES OVERNIGHT TOO. THIS  
WILL SET UP FOR EFFECTIVE RADIATIONAL COOLING, LEVERAGED THE CONSMOS  
FOR TONIGHT, WILL HAVE LOWS RANGING BETWEEN 5F AND -5F, AT THE COAST  
IT IS SLIGHTLY WARMER IN THE LOWER TEENS. A FEW SPOTS MAY COME NEAR  
THE DAILY RECORD LOWEST MINIMUM TEMPERATURE, LIKE PROVIDENCE WHERE  
THE FORECAST LOW IS 7F AND THE RECORD IS 2F. AS MENTIONED ABOVE WILL  
HAVE MORE DETAILS ON RECORDS IN THE CLIMATE SECTION OF THE AFD.  
 
DRY AND COLD, BUT WILL CONTINUE CHANCE OF A FEW OCEAN EFFECT SNOW  
SHOWERS DURING THE LATE EVENING, BUT AS WINDS EASE OVER THE WATERS  
THAT SHOULD END THOSE SNOW SHOWERS.  
 
MONDAY, THE 1035MB HIGH TRAVERSES ACROSS SOUTHERN NEW ENGLAND  
LEADING TO A SUNNY BUT STILL CHILLY DAY, JUST NOT AS COLD AS  
SUNDAY. TEMPERATURES AT 925MB MODERATE, -12C TO -8C, WHILE STILL  
CHILLY, HIGHS ARE IN THE MIDDLE TO UPPER 20S, WITH FAR  
NORTHWEST MASSACHUSETTS STILL IN THE UPPER TEENS TO LOWER 20S.  
SUNSHINE GIVES WAY TO INCREASE IN CLOUDS LATER IN THE DAY AHEAD  
OF A WEAK CLIPPER SYSTEM, MORE ON THAT IN THE LONG TERM SECTION  
OF THE AFD.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
 
 
UPDATED: 3:30 AM  
 
KEY MESSAGES:  
 
* LIGHT SNOW SHOWERS LATE MON NIGHT/TUE AM WITH ACCUM 1 INCH OR LESS  
 
* MAINLY DRY CHRISTMAS DAY INTO SAT, WITH JUST A LOW RISK FOR SPOTTY  
LIGHT PRECIP AT TIMES  
 
* TEMPS MODERATE INTO THE 30S TUE THROUGH THU WITH SOME 40S BY  
FRIDAY, BUT COLD NIGHTS  
 
DETAILS...  
 
MONDAY NIGHT AND TUESDAY...  
 
A SHORTWAVE APPROACHES FROM THE GT LAKES WITH A WEAK CLIPPER SYSTEM  
MOVING THROUGH THE REGION. LARGE SCALE FORCING INCREASES AHEAD OF  
THE SHORTWAVE WITH MOISTENING OF THE COLUMN LEADING TO A PERIOD OF  
LIGHT SNOW SHOWERS LATE MON NIGHT INTO TUE MORNING. PTYPE WILL BE  
MOSTLY SNOW BUT WARMING BOUNDARY LAYER MAY LEAD TO CHANGE TO RAIN  
SHOWERS FOR CAPE/ISLANDS. HOWEVER, THE COLUMN NEVER FULLY SATURATES  
SO NOT LOOKING AT MUCH SNOW, A COATING TO AN INCH, WITH PERHAPS 1-2  
INCHES IN NORTHERN MA WHERE ENSEMBLE GUIDANCE INDICATES MODERATE  
PROBS FOR 1+ INCH OF SNOW. THE SYSTEM IS A QUICK MOVER AND THE  
PRECIP SHOULD BE MOVING OUT IN THE AFTERNOON AS MUCH DRIER AIR MOVES  
IN FROM THE NORTH AS PWATS DROP TO LESS THAN 0.2". HIGHS WILL BE IN  
THE 30S, WITH LOWER 40S CAPE/ISLANDS.  
 
WEDNESDAY THROUGH SATURDAY...  
 
OVERALL A QUIET PERIOD AS NEW ENG WILL BE DOMINATED BY RIDGING ALOFT  
ALTHOUGH THERE COULD A SHORTWAVE INTERRUPTION SOMETIME AROUND THU.  
HOWEVER, DEEP LAYER MOISTURE WILL BE LIMITED AS STRONG HIGH PRES  
BUILDS TO THE NORTH. BUT THIS WILL ALSO SET UP A PERSISTENT LOW  
LEVEL N-NE FLOW WHICH MAY LEAD TO PERIODS OF LOW CLOUDS ALONG WITH  
SPOTTY LIGHT PRECIP OR DRIZZLE AT TIMES, ESPECIALLY NEAR THE COAST.  
BUT LARGELY A DRY PERIOD FOR MUCH OF THE TIME WITH NO STORMS THROUGH  
NEXT WEEKEND. DESPITE WARMING TEMPS ALOFT, THE STRONG HIGH TO THE  
NORTH WILL BRING SHALLOW COOLER AIR SO TEMPS WILL BE SLOW TO RESPOND  
WITH HIGHS GENERALLY IN THE 30S WED/THU WARMING INTO THE LOWER 40S  
FRI/SAT, WITH CHILLY NIGHTS.  
 

 
   
AVIATION /12Z SUNDAY THROUGH THURSDAY/
 
 
FORECAST CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
12Z TAF UPDATE...  
 
TODAY AND TONIGHT...HIGH CONFIDENCE.  
 
VFR, BUT OCEAN EFFECT CLOUDS WITH AREAS OF MVFR CIGS AND  
SCATTERED FLURRIES OVER THE OUTER CAPE, MAINLY ALONG AND EAST  
OF HYA. NW GUSTS TO 20-25 KT DIMINISHING LATER THIS AFTERNOON  
THEN BECOMING LIGHT TONIGHT.  
 
MONDAY...HIGH CONFIDENCE.  
 
VFR. LIGHT N WIND BECOMING S-SW 5-10 KT IN THE AFTERNOON.  
 
KBOS TAF...HIGH CONFIDENCE IN TAF.  
 
KBDL TAF...HIGH CONFIDENCE IN TAF.  
 
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...  
 
MONDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. CHANCE SN.  
 
TUESDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. CHANCE SN,  
CHANCE RA.  
 
TUESDAY NIGHT THROUGH THURSDAY: VFR.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS:  
LOW - LESS THAN 30 PERCENT.  
MEDIUM - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
UPDATED: 3:30 AM  
 
KEY MESSAGES:  
 
* SMALL CRAFT ADVISORY IN EFFECT THROUGH TONIGHT.  
 
* LIGHT ICING FROM FREEZING SPRAY FOR THE WATERS SURROUNDING  
NANTUCKET THROUGH SUNDAY AFTERNOON.  
 
TODAY THROUGH MONDAY...HIGH CONFIDENCE.  
 
HIGH PRESSURE MOVING OVERHEAD FROM THE GREAT LAKES REGION. NW  
WINDS 15 TO 20 KNOTS GUSTING TO 25 KNOTS THROUGH MID AFTERNOON  
WITH SEAS 5 TO 7 FEET. A FEW OCEAN EFFECT SNOW SHOWERS ARE  
POSSIBLE THROUGH THIS EVENING ACROSS THE EASTERN WATERS. WIND  
BECOMES LIGHT AND VARIABLE OVERNIGHT WITH SEAS FALLING BELOW 5  
FEET. MONDAY, WIND TURNS TO THE SOUTHWEST 10 TO 15 KNOTS WITH  
SEAS 2 TO 4 FEET.  
 
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...  
 
MONDAY NIGHT: WINDS LESS THAN 25 KT. CHANCE OF RAIN, CHANCE OF  
SNOW. LOCAL VISIBILITY 1 TO 3 NM.  
 
TUESDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.  
CHANCE OF RAIN, CHANCE OF SNOW. LOCAL VISIBILITY 1 TO 3 NM.  
 
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT. SLIGHT CHANCE OF RAIN SHOWERS, SLIGHT CHANCE OF SNOW  
SHOWERS. LOCAL VISIBILITY 1 TO 3 NM.  
 
CHRISTMAS DAY THROUGH WEDNESDAY NIGHT: WINDS LESS THAN 25 KT.  
AREAS OF SEAS APPROACHING 5 FT. SLIGHT CHANCE OF RAIN SHOWERS.  
 
THURSDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. SLIGHT CHANCE  
OF RAIN SHOWERS.  
 

 
   
CLIMATE
 
 
RECORD LOWEST MAXIMUM TEMPERATURE: 12/22  
 
BOS: 17F (1989)  
BDL: 11F (1989)  
PVD: 17F (1989)  
ORH: 9F (1989)  
 
RECORD LOWEST MINIMUM TEMPERATURE: 12/23  
 
BOS: -12F (1883)  
BDL: -5F (1989)  
PVD: 2F (1989)  
ORH: -2F (1989)  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR ANZ231-  
232-251.  
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR ANZ250-254.  
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ255.  
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ256.  
 

 
 

 
 
SYNOPSIS...KJC/DOOLEY  
NEAR TERM...DOOLEY  
SHORT TERM...DOOLEY  
LONG TERM...KJC  
AVIATION...KJC/DOOLEY  
MARINE...KJC/DOOLEY  
CLIMATE...DOOLEY  
 
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