783  
FXUS61 KBOX 152037  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
337 PM EST WED JAN 15 2025  
   
SYNOPSIS
 
 
QUIET WEATHER OVERNIGHT AND THURSDAY. A WEAK LOW PRESSURE SYSTEM MAY  
PRODUCE SOME FLURRIES OR LIGHT SNOW SHOWERS THURSDAY NIGHT.  
TEMPERATURES MODIFY TO NEAR TO ABOVE NORMAL LEVELS BY LATE IN  
THE WEEK INTO THE WEEKEND. A PASSING FRONTAL SYSTEM WILL BRING  
LIGHT AMOUNTS OF RAIN AND HIGHER ELEVATION SNOW SHOWERS  
SATURDAY. MONITORING POTENTIAL STORMINESS LATE SUNDAY NIGHT OR  
MONDAY BUT UNCERTAINTY REMAINS LARGE. BELOW NORMAL TEMPERATURES  
AND POTENTIALLY LOW WIND CHILLS THEN SET IN BY EARLY TO MIDDLE  
OF NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
335 PM UPDATE  
 
LATEST GUIDANCE SUGGEST NO REAL CHANGES FROM WHAT WE HAVE BEEN  
FORECASTING. BOTH THE GUSTY WINDS AND SCATTERED SHALLOW DAYTIME  
HEATING STRATO-CU CLOUDS WILL FADE WITH SUNSET. WITH THE WINDS DYING  
OFF, AND SKIES MOSTLY CLEAR AND A DRY AIRMASS IN PLACE, WE SHOULD  
SEE DECENT RADIATIONAL COOLING. LOWS WILL RANGE FROM THE SINGLE  
DIGITS TO TEENS. PERHAPS HOLDING AROUND 20F AT A FEW SPOTS ACROSS  
THE CAPE AND ISLANDS.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/
 
 
335 PM UPDATE  
 
KEY MESSAGES:  
 
* PERHAPS FLURRIES/LIGHT SNOW SHOWERS ALONG THE SOUTH COAST  
THURSDAY NIGHT.  
 
AGAIN, NO SIGNIFICANT CHANGES TO PRIOR FORECASTS. EXPECT A FAIRLY  
QUIET WEATHER DAY ON THURSDAY. STILL A CHILLY AIRMASS IN PLACE, WITH  
925MB TEMPERATURES AROUND -10C. THIS SUPPORTS HIGH TEMPERATURES IN  
THE UPPER 20S TO LOWER 30S ACROSS THE REGION. A FAST MOVING  
SHORTWAVE WILL BE APPROACHING THE REGION LATER IN THE DAY, SO EXPECT  
INCREASING MID-LEVEL CLOUDS AS THE DAY GOES ON. THE TROUGH PASSES  
THROUGH THURSDAY NIGHT, BUT WITH A VERY DRY AIRMASS (PRECIP WATER  
VALUES LESS THAN 0.3") AND NO REAL STRONG DYNAMICS, ANY  
PRECIPITATION WILL BE LIGHT. HI-RES GUIDANCE SUGGESTS PERHAPS A  
LITTLE BIT OF LIGHT SNOW, ESPECIALLY CLOSER TO THE SOUTH COAST, BUT  
NO ROBUST SIGNAL. KEPT THE POPS TO THE 30% RANGE FOR THAT AREA.  
NOTHING MORE THAN A DUSTING OF SNOW IS EXPECTED. COULD BE FLURRIES  
ELSEWHERE ACROSS SOUTHERN NEW ENGLAND, BUT GIVEN IT'S MID-WINTER,  
THAT REALLY ISN'T ANYTHING NOTEWORTHY.  
 

 
   
LONG TERM /FRIDAY THROUGH WEDNESDAY/
 
 
335 PM UPDATE  
 
KEY MESSAGES:  
 
* WARMING TREND TO TEMPS FRI-SUN, WITH PASSING RAIN AND HIGHER  
ELEVATION SNOW SHOWERS FOR SAT.  
 
* LIGHT-ACCUMULATING FLUFFY SNOW POSSIBLE SUN NIGHT INTO EARLY MON,  
ALTHOUGH STILL TOO UNCERTAIN FOR ACCUMULATIONS AT THIS TIME.  
 
* BELOW NORMAL TEMPS AND LOW WIND CHILLS FOR EARLY TO MID NEXT WEEK  
ASSOCIATED WITH COLDEST AIRMASS TO THIS POINT IN WINTER. HIGHS MAY  
STRUGGLE TO REACH THE MID TEENS IN INTERIOR CT AND MA.  
 
DETAILS:  
 
FRIDAY THROUGH SUNDAY:  
 
WARMING TREND TAKES PLACE IN THIS TIMEFRAME AS HIGH PRESSURE MOVES  
OFFSHORE AND USHERS IN AN INCREASING SOUTHERLY FLOW. HIGH TEMPS ARE  
EXPECTED TO RISE INTO THE MID 30S TO LOWER TO MID 40S BY SAT INTO  
SUN. DESPITE THE  
 
ALTHOUGH FRI LOOKS DRY, A WEAK FRONTAL SYSTEM SPREADS A ROUND OF  
PRECIPITATION INTO SOUTHERN NEW ENGLAND FOR SAT. TEMPS LOOK TO BE  
WARM ENOUGH FOR RAIN IN MOST LOCATIONS, WITH SNOW MIXING IN ACROSS  
THE HIGHER ELEVATIONS IN THE BERKSHIRES. TOTAL QPF RELATED TO THIS  
SYSTEM LOOKS LOW, WITH MOST ENSEMBLES INDICATING QPF AMTS OF A  
QUARTER-INCH OR LESS. OVERALL IMPACTS LOOK MINIMAL TO MINOR WITH  
REGARD TO THIS SYSTEM. POPS THEN DECREASE BRIEFLY INTO SUN, WITH DRY  
BUT CLOUDY WEATHER.  
 
SUNDAY NIGHT / EARLY MONDAY:  
 
WE CONTINUE TO MONITOR DEVELOPMENTS REGARDING THE POTENTIAL FOR LOW  
PRESSURE DEVELOPMENT AROUND LATE SUNDAY NIGHT INTO EARLY ON MONDAY  
TIMEFRAME. THIS IS ASSOCIATED WITH A SHORTWAVE DISTURBANCE AT 500 MB  
ROTATING AROUND A DEEP LONGWAVE TROUGH THAT IS FORECAST TO USHER IN  
THE COLDEST AIRMASS TO THIS POINT IN WINTER 2024-2025. THIS FORECAST  
SETUP IS ONE WHERE SFC LOW PRESSURE MAY DEVELOP ALONG A STRONG  
FRONTAL BOUNDARY WITH RELATED PRECIP FALLING ON THE COLD SIDE OF THE  
FRONTAL ZONE, IN AN ANAFRONTAL-WAVE LOW CONFIGURATION.  
 
EXACTLY WHERE AND IF THIS DEVELOPMENT OCCURS VARIES ACROSS THE  
GLOBAL NWP, WHICH CONTRIBUTES MUCH UNCERTAINTY IN THE FORECAST.  
CLUSTER ANALYSES OF THE VARIOUS GLOBAL ENSEMBLE MEMBERS, IN  
PARTICULAR, KEY ON DETAILS REGARDING THE STRENGTH OF THE INITIATING  
SHORTWAVE AS IT DIGS INTO THE FOUR CORNERS REGION LATE FRI NIGHT/SAT  
WILL GREATLY SHAPE WHERE AND HOW STRONG THIS LOW PRESSURE MAY  
BECOME. THE INTERNATIONAL SUITE OF GUIDANCE IS A BIT MORE BULLISH ON  
QPF RELATED TO THIS WAVE, WHILE THE GFS IS FURTHER OFFSHORE BUT  
WOULD STILL BRING A MORE LIMITED DEGREE OF QPF TO EASTERN PORTIONS  
OF SNE.  
 
THE POTENTIAL EXISTS FOR AT LEAST A LIGHT/MINOR ACCUMULATION OF SNOW  
DURING THE OVERNIGHT HOURS INTO EARLY MONDAY. WITH FEW EXCEPTIONS,  
PAST ANAFRONTAL-WAVE TYPE LOWS ARE NOT TYPICALLY SUBSTANTIAL PRECIP-  
MAKERS AND THE FAST 500 MB WSWLY BELT OF FLOW COULD FAVOR A MORE  
PROGRESSIVE/FASTER-MOVING WAVE. DEPENDING ON HOW QUICKLY THE COLDER  
AIR FILTERS IN, ANY SNOW WHICH DEVELOPS COULD HAVE A MORE  
FLUFFY/POWDERY CHARACTER. BUT GIVEN THE ABOVE UNCERTAINTIES IN LARGE-  
SCALE FIELDS, IT IS STILL TOO EARLY TO PROVIDE SPECIFICS ON  
ACCUMULATIONS AT THIS TIME.  
 
EARLY TO MID NEXT WEEK:  
 
ALTHOUGH IT LOOKS DRY, THE MAIN STORY IN THIS PERIOD IS WELL BELOW  
NORMAL TEMPERATURES AND LOW WIND CHILLS ASSOCIATED WITH WHAT IS  
EASILY THE COLDEST AIRMASS TO THIS POINT IN WINTER 2024-2025.  
COLDEST AIR SETTLES IN ON TUE AND WED WITH 925 MB TEMPS FALLING TO  
AROUND -17 TO AS LOW AS -20C! NOTE THAT MEX MOS FORECAST LOWS ARE  
SOME 10-15 DEGREES BELOW LATE JAN CLIMATOLOGY HIGHS, AND SINCE MEX  
MOS FORECASTS TENDS TO LEAN CLOSER TO CLIMO IN LATER FORECAST  
TIMEFRAMES, THESE ANOMALIES COMPARED TO MOS ARE A PRETTY TELLING  
SIGNAL ABOUT THE POTENTIAL FOR BELOW NORMAL TEMPS.  
 
HIGHS IN SOME INTERIOR LOCATIONS MAY STRUGGLE TO REACH THE MID  
TEENS, WITH UPPER TEENS TO MID 20S FOR THE COASTAL PLAIN/LARGER  
CITIES. ALTHOUGH THERE ARE SOLID PROBS OF SUB-ZERO WINDCHILLS, HOW  
LOW WIND CHILLS MAY GET IS STILL UNCLEAR AS THIS WILL OBVIOUSLY  
DEPEND ON WIND SPEEDS. PENDING THOSE VALUES, IT IS NOT OUT OF THE  
REALM OF POSSIBILITY THAT COLD HAZARD HEADLINES COULD BE NEEDED IN  
SOME LOCATIONS IN THIS TIMEFRAME.  
 

 
   
AVIATION /21Z WEDNESDAY THROUGH MONDAY/
 
 
FORECAST CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
18Z TAF UPDATE...  
 
HIGH CONFIDENCE FOR THE NEXT 24-30 HOURS.  
 
VFR AREA WIDE, WITH SCATTERED STRATOCUMULUS, ESPECIALLY WESTERN  
AREAS. NW SURFACE WINDS STILL GUSTING 20-25KT, WITH A FEW SPOTS  
UP TO 30KT. THOSE WINDS WILL SLOWLY DIMINISH DURING THE  
AFTERNOON, WITH THE GUSTINESS COMING TO AN END BY 00Z. THE  
CLOUDS SHOULD ALSO DISSIPATE SHORTLY AFTER SUNSET, LEADING TO  
SKC CONDITIONS OVERNIGHT. WINDS WILL SLOWLY TRANSITION TO W AND  
THEN SW LATE TONIGHT AND THURSDAY MORNING, WITH WINDS ONLY  
AROUND 10KT. VFR CONTINUES ALL DAY THURSDAY. SKC TO START, WITH  
MID LEVEL CLOUDS MOVING IN DURING THE AFTERNOON. FOR THURSDAY  
NIGHT, VFR IS EXPECTED TO CONTINUE FOR MOST OF THE AREA,  
ALTHOUGH SOME MVFR IS POSSIBLE, ESPECIALLY CLOSER TO SOUTH  
COASTAL AREAS IF WE SEE ANY FLURRIES/LIGHT SNOW SHOWERS DEVELOP.  
 
KBOS TAF...HIGH CONFIDENCE IN TAF.  
 
KBDL TAF...HIGH CONFIDENCE IN TAF.  
 
OUTLOOK /FRIDAY THROUGH MONDAY/...  
 
FRIDAY: VFR.  
 
FRIDAY NIGHT: VFR. BREEZY.  
 
SATURDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY. CHANCE  
RA.  
 
SATURDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY.  
CHANCE RA.  
 
SUNDAY: VFR. SLIGHT CHANCE RA, SLIGHT CHANCE SN.  
 
SUNDAY NIGHT: VFR. BREEZY. CHANCE SN.  
 
MARTIN LUTHER KING JR DAY: VFR. BREEZY. SLIGHT CHANCE SN.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MEDIUM - 30 TO 60 PERCENT.  
HIGH- GREATER THAN 60 PERCENT.  
 
335 PM UPDATE  
 
HIGH CONFIDENCE.  
 
WINDS WILL BE DIMINISHING OVERNIGHT, SO THE CURRENT PROJECTION THAT  
SMALL CRAFT ADVISORIES WILL BE ABLE TO BE DISCONTINUED LOOK TO BE ON  
TRACK. GENERALLY LIGHT WINDS (15KT AND LESS) ARE EXPECTED THURSDAY  
NIGHT THROUGH FRIDAY.  
 
OUTLOOK /FRIDAY THROUGH MONDAY/...  
 
FRIDAY THROUGH FRIDAY NIGHT: WINDS LESS THAN 25 KT.  
 
SATURDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 25 KT. SEAS UP TO 5 FT. CHANCE OF RAIN.  
 
SATURDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. RAIN  
LIKELY.  
 
SUNDAY: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS. CHANCE OF  
RAIN.  
 
SUNDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS.  
CHANCE OF RAIN, CHANCE OF SNOW.  
 
MARTIN LUTHER KING JR DAY: LOW RISK FOR SMALL CRAFT ADVISORY  
WINDS WITH GUSTS UP TO 25 KT. AREAS OF ROUGH SEAS. CHANCE OF  
SNOW, CHANCE OF FREEZING SPRAY.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ230-  
232>237.  
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ231-251.  
SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ250-  
254>256.  
 

 
 

 
 
SYNOPSIS...LOCONTO/NASH  
NEAR TERM...NASH  
SHORT TERM...NASH  
LONG TERM...NASH  
AVIATION...LOCONTO/NASH  
MARINE...LOCONTO/NASH  
 
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