057
FXUS61 KALY 150535
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1235 AM EST SUN DEC 15 2024
SYNOPSIS
COLD CONDITIONS WILL CONTINUE ON SUNDAY BEFORE A DISTURBANCE
BRINGS SOME RAIN, SNOW AND POSSIBLE LOCALIZED WINTRY MIX SUNDAY
NIGHT INTO MONDAY. MILDER WEATHER RETURNS LATER MONDAY THROUGH
TUESDAY AS A FRONTAL SYSTEM BRINGS A WIDESPREAD RAINFALL.
ANOTHER SYSTEM WILL LIKELY BRING AREAS OF RAIN AND SNOW LATER IN
THE WEEK.
NEAR TERM /UNTIL 6 AM THIS MORNING/
KEY MESSAGE:
- DRY AND CLEAR TONIGHT WITH BELOW NORMAL TEMPERATURES
DISCUSSION:
SURFACE HIGH PRESSURE CENTERED OVER THE ST LAWRENCE VALLEY AND
NORTHERN NEW ENGLAND EARLY THIS MORNING CONTINUES TO SLOWLY
SHIFT EASTWARD AS THE AXIS OF UPPER-LEVEL RIDGING APPROACHES
FROM THE WEST. LARGELY CLEAR SKIES THROUGH THE EARLY PART OF THE
OVERNIGHT PERIOD HAVE ALLOWED TEMPERATURES TO RAPIDLY FALL INTO
THE SINGLE DIGITS AND TEENS, AS WELL AS A FEW NEGATIVE READINGS
IN THE SOUTHERN ADIRONDACKS. HIGH CLOUDS ARE BEGINNING TO
SPREAD ACROSS THE REGION FROM THE SOUTHWEST, HOWEVER, WHICH
WILL ACT TO STYMIE ADDITIONAL RADIATIVE COOLING, WITH
TEMPERATURES ONLY SLOWLY TRENDING DOWNWARD THROUGH SUNRISE.
SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/
KEY MESSAGES:
- DRY DAYTIME SUNDAY WITH PRECIPITATION CHANCES INCREASING INTO
MONDAY
- LIGHT SNOW LATE SUNDAY NIGHT INTO MONDAY MORNING WITH A
CHANCE OF A MIX WITH FREEZING RAIN IN THE EASTERN CATSKILLS,
MID HUDSON VALLEY, SOUTHERN BERKSHIRES AND LITCHFIELD HILLS
- PRECIPITATION CHANGES TO ALL RAIN BY MONDAY AFTERNOON AS
TEMPERATURES WARM
- RAIN EXPECTED MONDAY NIGHT AND TUESDAY
- TEMPERATURES MODERATING BACK TO NEAR NORMAL
DISCUSSION:
DRY SUNDAY WITH INCREASING CLOUDS AS THE UPPER SYSTEM AND WARM
FRONT APPROACH SUNDAY NIGHT. STRENGTHENING WARM ADVECTION,
SOUTHWEST BOUNDARY LAYER FLOW WITH LOW LEVEL CONVERGENCE AND
ISENTROPIC LIFT WILL SUPPORT SNOW DEVELOPING AND SPREADING
THROUGH OUR REGION LATER SUNDAY EVENING AND THROUGH THE NIGHT
INTO EARLY MONDAY MORNING. THERMAL PROFILES SUGGEST ALL SNOW,
BUT A WET SNOW WITH BELOW CLIMO SLRS INTO EARLY MONDAY MORNING.
THIS SUGGESTS THAT SNOW AMOUNTS SHOULD BE JUST BELOW ADVISORY
CRITERIA IN THE SOUTHERN ADIRONDACKS, WESTERN AND CENTRAL
MOHAWK VALLEY, EASTERN CATSKILLS, SOUTHERN VT AND NORTHERN
BERKSHIRES, WIT 1 TO 4 INCHES. A DUSTING TO AN INCH IS POSSIBLE
ELSEWHERE.
AROUND DAYBREAK AND THROUGH THE MORNING, SURFACE TEMPERATURES
WILL LIKELY STRUGGLE TO WARM AS BOUNDARY LAYER TEMPERATURES
WARM. SO, THERE ARE CHANCES FOR PATCHY LIGHT FREEZING RAIN,
ESPECIALLY FROM THE EASTERN CATSKILLS TO MID HUDSON VALLEY,
SOUTHERN BERKSHIRES AND LITCHFIELD HILLS. SOUTHWEST BOUNDARY
LAYER FLOW DOES NOT MIX DOWN VERY EFFICIENTLY WHEN THE GROUND IS
SO COLD. SO, IT WILL PROBABLY TAKE UNTIL MIDDAY FOR SURFACE
TEMPERATURES TO WARM ENOUGH ABOVE FREEZING TO CHANGE EVERYTHING
TO A COLD RAIN. THEN TOWARD SUNSET AND AFTER SUNSET, THE DAYTIME
HIGHS SHOULD OCCUR. HIGHS MONDAY IN THE MID 30S TO LOWER 40S.
PRECIPITATION DECREASES IN COVERAGE MONDAY AFTERNOON BUT THEN
THE NEXT LARGER SYSTEM BEGINS TO AFFECT OUR REGION AS UPPER
ENERGY APPROACHES FROM THE MIDWEST AND WESTERN GREAT LAKES.
BOUNDARY LAYER WINDS INCREASE AND DEEP MOISTURE ADVECTS
NORTHWARD AS LOW LEVEL CONVERGENCE AND ISENTROPIC LIFT
INCREASES. A SOAKING RAIN IS EXPECTED MONDAY NIGHT AND TUESDAY
WITH HIGHS TUESDAY IN THE UPPER 40S TO LOWER 50S WITH A FEW MID
50S MID HUDSON VALLEY AND AROUND 40 TO LOWER 40S SOUTHERN
ADIRONDACKS.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
MEAN, BROAD UPPER TROUGH OVER THE REGION WITH EMBEDDED UPPER
IMPULSES THROUGH THE PERIOD. LONG RANGE GUIDANCE/ENSEMBLES ARE
SHOWING SOME SPREAD IN THE TIMING AND TRACK OF UPPER IMPULSES.
SO, GENERALLY AN UNSETTLED PERIOD WITH CHANCES FOR RAIN AND SNOW
SHOWERS BUT DIFFICULT TO TIME THE BEST CHANCES. INCLUDING
CHANCES FOR RAIN AND SNOW SHOWERS THE ENTIRE PERIOD FROM
WEDNESDAY THROUGH SATURDAY.
HIGHS WEDNESDAY IN THE 40S WITH 30S HIGHER TERRAIN. HIGHS
THURSDAY IN THE UPPER 30S TO LOWER 40S WITH A FEW MID 40S MID
HUDSON VALLEY AND AROUND 30 TO LOWER 30S HIGHER TERRAIN. HIGHS
FRIDAY AND SATURDAY IN THE 30S WITH 20S HIGHER TERRAIN.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
IR SATELLITE IMAGERY SHOWS HIGH CLOUDS STARTING TO SPREAD ACROSS
THE REGION. WHILE IT WILL REMAIN VFR THROUGH THE REST OF THE
OVERNIGHT, CIRRUS CLOUDS AROUND 25 KFT WILL BUILD INTO THE
REGION FROM THE SOUTHWEST, ALLOWING FOR BKN-OVC CIGS BY THE LATE
NIGHT HOURS. WINDS WILL CONTINUE TO BE VERY LIGHT OR CALM
THROUGH THE REST OF THE OVERNIGHT HOURS.
IT WILL STAY DRY THROUGH THE ENTIRE DAY ON SUNDAY. CLOUDS WILL
GRADUALLY LOWER AND THICKEN, WITH BKN-OVC CIGS AROUND 15 KFT
MOVING IN BY LATER IN THE DAY ON SUNDAY. A LIGHT SOUTH TO
SOUTHEAST WIND AROUND 5 KTS WILL DEVELOP AT ALL SITES BY THE
AFTERNOON HOURS.
A PERIOD OF LIGHT SNOW WILL SPREAD ACROSS THE AREA FOR SUNDAY
NIGHT. IT SHOULD START IMPACTING THE TAF SITES AROUND 02Z-04Z
AND WILL CONTINUE FOR MUCH OF THE OVERNIGHT HOURS. P-TYPE LOOKS
TO BE SNOW FOR ALL TAF SITES. IFR CONDITIONS ARE EXPECTED WITHIN
SNOWFALL, MAINLY FOR VISIBILITY. WINDS WILL CONTINUE TO BE
RATHER LIGHT, MAINLY 5 KTS OR LESS ON SUNDAY NIGHT FROM AN
EASTERLY DIRECTION.
OUTLOOK...
MONDAY: MODERATE OPERATIONAL IMPACT. LIKELY RA...SN.
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...RATHBUN
NEAR TERM...PICARD
SHORT TERM...NAS
LONG TERM...NAS
AVIATION...FRUGIS
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