069
FXUS61 KGYX 191745
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1245 PM EST THU DEC 19 2024
SYNOPSIS
COOLER AIR COMES IN BEHIND EXITING LOW PRESSURE WITH UPSLOPE
SNOW SHOWERS IN THE MOUNTAINS. A WEAK CLIPPER PASSES THROUGH
FRIDAY NIGHT, WITH VERY COLD AIR MOVING INTO NEW ENGLAND FOR
THE WEEKEND. ALTHOUGH IT WILL GRADUALLY MODERATE TO NEAR NORMAL
BY THE MIDDLE OF NEXT WEEK, AS STRONG HIGH PRESSURE SETTLES OVER
THE REGION.
NEAR TERM /UNTIL 6 PM THIS EVENING/
1245 PM UPDATE...MINOR UPDATE TO SKY COVER AND POPS TO ALIGN
WITH OBSERVED TRENDS.
805 AM UPDATE...HAVE MADE SOME MINOR TWEAKS TO POPS AS RADAR
AND SURFACE OBS SHOW SOME LIGHT SNOW SHOWERS ACROSS WEST-
CENTRAL NH SOUTH OF THE WHITE MOUNTAINS. OTHERWISE NO
SIGNIFICANT CHANGES TO THE GOING FORECAST FOR TODAY.
625 AM...SURFACE TROUGH HAS COMPLETELY EXITED THE CWA, AND WE
ARE LEFT WITH SOME UPSLOPE SHSN. THIS WILL LIKELY FLARE UP AND
DOWN THROUGH THE DAY, BUT SHOULD DIMINISH LATE IN THE DAY. I
MODIFIED SKY A LITTLE BIT THIS MORNING, AND THEN JUST ADJUSTED
T/TD BASED ON CURRENT OBS.
PREVIOUSLY...BACK EDGE OF PRECIP FROM THE DOUBLE BARRELED SFC
LOW WILL CONTINUE TO SHIFT SE OUT OF THE CWA BY 10Z. TEMPS ARE
COOLING A BIT BUT CAN'T SEE ANYPLACE THAT’S BEEN ALL RAIN UP TO
THIS POINT SEEING ANYTHING MORE THAN FEW SNOW FLAKES MIXING IN
AT THE END. AS WINDS SHIFT TO THE W EARLY THIS MORNING, AND
EVENTUALLY NW LATER THIS MORNING WILL SILL SEE UPSLOPE SHSN
START TO DEVELOP AS WELL AS DOWNSLOPE CLEARING, WHICH SHOULD
HAPPEN AROUND OR SHORTLY AFTER SUNRISE. OTHERWISE THAT WILL BE
THE TREND FOR TODAY WITH DOWNSLOPE CLEARING AND UPSLOPE SHSN
AND CLOUDS IN THE MTNS. THE MTNS WON'T SEE MUCH IN THE WAY ANY
TEMP INCREASE TODAY AS THE CAA AND THE CLOUDS COMBINE TO KEEP
THE TEMPS DOWN, AND HIGHS HERE WILL BE AROUND 30, AND THAT WILL
LIKELY BE THIS MORNING. IN THE DOWNSLOPE S AND E OF THE MTNS
LOOK FOR HIGHS IN THE UPPER TO LOW 40S, WHICH STILL ISN'T A
GREAT INCREASE OVER CURRENT TEMPS. BREEZY NW FLOW FLOW IS
EXPECTED BUT GUSTS WILL BE LIMITED TO 20-25 MPH.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/
SFC HIGH PASSES TO THE N TONIGHT, AND ALTHOUGH THE EVENING WILL
SEE LIGHT NNW FLOW, SHOULD BE SOME LATE DECOUPLING. THIS WILL
BE LIMITED BY CIRRUS IN THE S, BUT IF IT CLEARS OUT ENOUGH SOME
OF THE MTN VALLEYS WILL LIKELY SEE MINS FROM 5-10 ABOVE, WHILE
TO THE S LOOK FOR LOWS IN THE UPPER TEENS TO LOW 20S.
LOW PRESSURE BEGINS TO DEVELOP OFF THE N CAROLINA COAST FRIDAY
MORNING AND TRACKS NE TO S OF NS BY FRI EVENING. THIS SYSTEM
DEVELOPS IN THE DOWNSTREAM FLOW ON THE E SIDE OF A LARGE 500 MB
TROUGH THAT EXTENDS FROM JAMES BAY TO THE GREAT LAKES. THE
FORECAST QUESTION IS HOW WELL DO THESE TWO SYSTEMS INTERACT
FRIDAY AFTERNOON INTO FRIDAY EVENING, AND WILL IT BE ENOUGH TO
PRODUCE SOME LIGHT SN CLOSE TO THE COAST, OR JUST SOME SHSN.
THERE’S AN OUTSIDE CHC FOR SOME VERY LIGHT SNOW ACCUMS IN THIS
PERIOD. OTHERWISE, ANY SUN FRIDAY MORNING WILL FADE BEHIND
CLOUDS BY THE AFTERNOON WITH HIGHS RANGING FROM THE LOW 20S IN
THE MTNS TO AROUND 30 IN THE S.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
UPDATE...SNOW SHOWERS STILL POSSIBLE FRIDAY AND FRIDAY NIGHT
WITH UPPER TROUGH BUT IT STILL LOOKS LIKE ORGANIZED
PRECIPITATION WITH DEVELOPING LOW REMAINS OFFSHORE. COLD TEMPS
CONTINUE TO BE THE MAIN THEME IN THE LONG TERM.
PREVIOUSLY...
IMPACTS:
- SOME OF THE COLDEST AIR OF THE CALENDAR YEAR OF 2024 WILL
BRING SUB-ZERO WIND CHILL READINGS, ESPECIALLY ON SATURDAY
NIGHT TO THE MAJORITY OF THE REGION.
- LIGHT SNOW SHOWERS POSSIBLE ON FRIDAY
- VERY LOW CONFIDENCE FOR LIGHT SNOW ON CHRISTMAS EVE
OVERVIEW: NORTHEAST CONUS WILL BE UNDER A LONGWAVE TROUGH FRIDAY
THROUGH MONDAY NEXT WEEK BRINGING WELL BELOW NORMAL TEMPERATURES
THIS WEEKEND. 500MB HEIGHTS INCREASE TUESDAY THROUGH WEDNESDAY
NEXT WEEK WITH A RETURN TO ZONAL FLOW. OVERALL FORECAST
CONFIDENCE OF PATTERN EVOLUTION IS ABOVE NORMAL THROUGH MONDAY
BEFORE SPREAD INCREASES SIGNIFICANTLY BY CHRISTMAS.
FORECAST DETAILS: STRONG CAA ON SATURDAY AS A ARCTIC SHOT OF
AIR MOVES INTO NEW ENGLAND, THIS WILL BRING WIND CHILL VALUES
IN THE SUB-ZERO READINGS FROM SATURDAY EVENING THROUGH SUNDAY
MORNING FOR MOST AREAS, WITH A VERY COLD WEEKEND EXPECTED AT THE
SKI RESORTS. SNOW SHOWER ACTIVITY WILL PEAK IN THE MOUNTAINS ON
NW FLOW ON SATURDAY BEFORE ENDING BY SUNDAY MORNING. HIGH
PRESSURE CRESTS OVER THE AREA SUNDAY NIGHT WITH A POSSIBLE
OPTIMAL RADIATIONAL COOLING NIGHT, THE QUESTION WILL BE, HOW LOW
WILL IT GO IN REGARDS TO TEMPERATURES. SOME COLD SPOTS COULD
REACH -15F WITH CLOSE TO ZERO FOR MOST AREAS. TEMPERATURES WILL
BEGIN TO MODERATE ON MONDAY AS FLOW BECOMES MORE ZONAL.
FORECAST CONFIDENCE IS VERY LOW FOR SENSIBLE WEATHER NEXT WEEK
WITH A WEAK WAVE COMING ACROSS THE UPPER PLAINS THAT THE MODELS
AREN'T SURE TO DO WITH. DIFFICULT TO LATCH ONTO ANYTHING AT THIS
POINT, SO STUCK CLOSE WITH THE NBM, BUT A PERIOD OF SNOW CAN'T
COMPLETELY BE RULES AT BEFORE CHRISTMAS FOR COASTAL AREAS.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
SHORT TERM...ALL TERMINALS, EXCEPT KHIE, SHOULD IMPROVE TO VFR
BY 09-10Z, AND SHOULD EXPECT VFR THROUGH TONIGHT AND INTO FRIDAY
MORNING. KHIE WILL LIKELY BE STUCK MAINLY AT MVFR WITH SOME
SHSN ALTHOUGH SHOULD IMPROVE TO VFR LATER IN THE DAY. FRIDAY
AFTERNOON, A COASTAL STORM PASSING OFF SHORE COULD BRING SOME
LIGHT SN TO COASTAL TERMINALS AS WELL AS KMHT/KCON, ALTHOUGH
THIS WILL TEND MORE TOWARD MVFR THAN IFR.
LONG TERM...MVFR CIGS AND VISIBILITY COULD POSSIBLE RETURN ON
FRIDAY DUE TO SOME LIGHT SHOWER ACTIVITY, BUT OVERALL AVIATION
IMPACTS WILL BE LIMITED. WILL HAVE TO WATCH PORTSMOUTH DUE TO
THE POTENTIAL OF SOME LOCAL OCEAN ENHANCEMENT SNOW FRIDAY
AFTERNOON BUT A LOW PROBABILITY OUTCOME AT THIS TIME. COLD AND
WINDY FOR THE REMAINDER OF THE WEEKEND, WITH SNOW SHOWERS
IMPACTING WHITEFIELD ON SATURDAY.
MARINE
SHORT TERM...WNW WINDS WILL PICK THIS MORNING, WITH SCA GUSTS
EXPECTED THROUGH THE DAYLIGHT, BUT WINDS SHOULD DIMINISH AFTER
SUNSET, WITH SUB-SCA CONDS THROUGH MUCH OF FRI. BUT COULD SEE
ANOTHER ROUND OF GUSTY NW WINDS APPROACHING SCA LEVELS FRI
NIGHT.
LONG TERM...A DEVELOPING SURFACE LOW FRIDAY WILL STAY
WELL OFFSHORE BEFORE DEEPENING OVER THE CANADIAN MARITIMES THIS
WEEKEND. THIS WILL BRING SCA CONDITIONS TO THE WATERS ONCE AGAIN
AS A COLD FRONT AND ARCTIC SHOT OF AIR PUSH THROUGH THE AREA.
THIS WILL BE THE COLDEST AIRMASS OF THE SEASON THUS FAR.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ150>154.
NEAR TERM...CEMPA/SCHROETER
SHORT TERM...CEMPA
LONG TERM...DUMONT/EKSTER
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