288
FXUS61 KALY 170030
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
830 PM EDT FRI APR 16 2021
SYNOPSIS
SNOW IN THE HIGHER TERRAIN OF WESTERN NEW ENGLAND AND SCATTERED
RAIN SHOWERS ELSEWHERE WILL COME TO AN END TONIGHT. THEN, A
WEAK AREA OF HIGH PRESSURE MOVES IN FOR SATURDAY GIVING US A
COOL YET DRY DAY. THEN, MILDER TEMPERATURES ARRIVE FOR SUNDAY
WITH SOME ISOLATED AFTERNOON SHOWERS ONCE AGAIN POSSIBLE.
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
ALL WINTER WEATHER HAZARDOUS HEADLINES HAVE BEEN CANCELLED
ACROSS THE REGION. ADDITIONAL ACCUMULATIONS WILL BE LIGHT
TONIGHT WITH POTENTIAL FOR SOME BLACK ICE ON UNTREATED SURFACES
WHERE TEMPERATURES APPROACH THE FREEZING MARK. OTHERWISE,
VERTICALLY STACKED LOW OVER CAPE COD IS SHOWING SIGNS OF
DEPARTING TO THE ESE WHICH WILL REDUCE ITS INFLUENCE ACROSS THE
REGION TONIGHT.
FROM EARLIER, SNOWFALL AMOUNTS SO FAR HAVE RANGED BETWEEN 5 AND
10 INCHES IN THE SOUTHERN GREEN MOUNTAINS, 0.5 TO 3 INCHES IN
THE CT RIVER VALLEY OF SOUTHERN VT, 3 TO 5 IN THE SOUTHERN
ADIRONDACKS AND HIGHER TERRAIN AREAS OF BERKSHIRE AND LITCHFIELD
COUNTY, 2 TO 4 INCHES IN THE EASTERN CATSKILLS INCLUDING THE
HIGHER TERRAIN AREAS OF THE HELDERBERGS WITH GENERALLY LESS THAN
AN INCH ELSEWHERE IN EASTERN NY.
IN EASTERN NY, CONVECTIVELY DRIVEN ISOLATED TO SCATTERED RAIN
SHOWERS HAVE POPPED UP DUE TO THE COLD POOL ALOFT. THE 12 UTC
BUF SOUNDING SHOWED SOME STEEP LAPSE RATES ALOFT WHICH EXPLAINS
WHY WE HAVE RECEIVED SOME REPORTS IN THE CATSKILLS OF GRAUPEL.
OTHERWISE, EXPECT CLOUDY SKIES AND COOL TEMPERATURES WITH
LOWS NEAR FREEZING ACROSS THE HIGHER TERRAIN TO MID 30S FOR
VALLEY LOCATIONS.
SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/
SATURDAY SHOULD SEE MORNING CLOUDS THAT BREAK FOR SOME
AFTERNOON SUN AS WEAK HIGH PRESSURE MOVES OVERHEAD. TEMPERATURES
WILL STAY BELOW NORMAL THANKS TO CONTINUED NORTHWEST FLOW AND
SHOULD ONLY RISE INTO THE LOW TO MID 50S WITH MID TO UPPER 40S
FOR THE HIGHER TERRAIN.
NORTHWEST FLOW BECOMES MORE WESTERLY AND ZONAL ON SUNDAY WHICH
SHOULD HELP TEMPERATURES BECOME MILDER. GUIDANCE SHOWS A WEAK
SHORTWAVE ALOFT THAT SHIFTS EASTWARD INTO OUR AREA DURING THE
AFTERNOON WHICH COULD RESULT IN STEEPENED LAPSE RATES AND DEEPER
BOUNDARY LAYER MIXING. THEREFORE, WE SIDED WITH THE MILDER
GUIDANCE FOR AFTERNOON HIGH TEMPERATURES AND SHOW HIGHS RISING
INTO THE UPPER 50S TO LOW 60S, ESPECIALLY IN VALLEY AREAS.
BUFKIT SOUNDINGS SHOW THAT THE CONVECTIVE TEMPERATURE SHOULD BE
MET WHICH MAY GENERATE SOME ISOLATED OR SCATTERED SHOWERS,
ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. SOME PARTIAL
CLEARING OVERNIGHT SHOULD LED TO COOL TEMPERATURES FALLING INTO
THE MID TO UPPER 30S.
LONG TERM /MONDAY THROUGH FRIDAY/
WE BEGIN THE WORK/SCHOOL WEEK WITH AN INCREASE IN CLOUD COVERAGE AND
THE CHANCE FOR SOME SHOWERS. GLOBAL AND SHORT TERM MODELS DIFFER
WITH TIMING AND PLACEMENT OF THE APPROACHING SHORT WAVE LATER MONDAY
WITH THE ECMWF THE MOST AGGRESSIVE OF THE AVAILABLE GUIDANCE. SO WE
WILL INCREASE POPS A BIT BY MONDAY AFTERNOON WITH HIGHS GENERALLY
INTO THE 50S ACROSS THE TERRAIN TO LOWER HALF OF THE 60S FOR THE
VALLEY LOCATIONS.
THEREAFTER, SOUTHERLY FLOW INCREASES QUICKLY INTO TUESDAY AS
UPSTREAM TROUGH AXIS AMPLIFIES. WE COULD BENEFIT WITH THE POSITIVE
H850 TEMPERATURES AND DOWNSLOPING UNDER MID-APRIL SUNSHINE TO SEE
VALLEY TEMPERATURES APPROACH 70F WITH GENERALLY 60S ELSEWHERE. COULD
ALSO SEE LOWER DEWPOINTS WITH ENHANCE MIXING WHICH WE ACCOUNTED FOR
WITHIN THE EXTENDED GRIDS.
TUESDAY NIGHT INTO WEDNESDAY, INCREASING FRONTOGENESIS UPSTREAM AS
VIGOROUS SHORT WAVE ROUNDS THE BASE OF THE UPSTREAM TROUGH FOR
CONVECTION TO DEVELOP UPSTREAM AND LOWER STRATUS/DRIZZLE POTENTIAL
FOR OUR REGION OVERNIGHT INTO WEDNESDAY MORNING. WITH THE APPROACH
OF THE STRONG COLD FRONT, AND DEPENDING IF WE ARE ABLE TO DESTABILIZE
FURTHER, COULD SEE SOME THUNDERSTORMS WITH THE FRONTAL PASSAGE.
MUCAPES FROM THE GFS/ECMWF ARE PROGGED TO BE INTO THE LOWER 100 J/KG
WITH INCREASING SHEAR PROFILES. GRANTED, THIS IS FAR OUT IN THE
EXTENDED AND PER COORDINATION WITH NEIGHBORING OFFICES, WE WILL
INTRODUCE A SLIGHT CHANCE THUNDERSTORMS FOR THE SOUTHERN 1/2 OF THE
CWA WEDNESDAY AFTERNOON.
WEDNESDAY NIGHT INTO THURSDAY, STRONG COLD ADVECTION WITH A RETURN
OF SUB-ZERO H850 TEMPERATURES COULD SEE A TRANSITION OR MIXTURE OF
RAIN AND SNOW SHOWERS AS DEEP MOIST CYCLONIC FLOW IS EXPECTED ACROSS
THE REGION. TEMPERATURES DIP BACK AT OR BELOW FREEZING WEDNESDAY
NIGHT WITH BELOW NORMAL HIGH TEMPERATURES ON THURSDAY (40S AND LOWER
50S).
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
A FEW STRAGGLER -SHRA CONTINUE TO ROTATE IN VICINITY OF
TERMINALS FROM LOW PRESSURE NEAR CAPE COD. THE TREND ON THIS
ACTIVITY HAS BEEN TO DIMINISH THROUGH THE LATE AFTERNOON AND NOW
EARLY EVENING. HI RES MODELS DEPICT A CONTINUATION OF THIS
SCENARIO. FOR THE MOST PART WILL DEAL WITH THE ACTIVITY WITH
VCSH. HOWEVER RADAR DEPICTING A FEW (SLIGHTLY) STRONG CELLS
MOVING NEAR KPOU AND KPSF. SO, AT THESE LOCATIONS A TEMPO GROUP
WILL COVER IT. AT ALL TERMINALS LOOKING AT MVFR CONDITIONS
THROUGH THE NIGHT AND INTO SATURDAY MORNING.
CONDITIONS WILL EVOLVE TO VFR AT ALL TERMINALS BY SATURDAY
AFTERNOON.
OUTLOOK...
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: LOW OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY: HIGH OPERATIONAL IMPACT. BREEZY. LIKELY SHRA...TSRA.
FIRE WEATHER
SNOW IN THE HIGHER TERRAIN OF WESTERN NEW ENGLAND AND SCATTERED
RAIN SHOWERS ELSEWHERE WILL COME TO AN END TONIGHT. THEN, A
WEAK AREA OF HIGH PRESSURE MOVES IN FOR SATURDAY GIVING US A
COOL YET DRY DAY. THEN, MILDER TEMPERATURES ARRIVE FOR SUNDAY
WITH SOME ISOLATED AFTERNOON SHOWERS ONCE AGAIN POSSIBLE.
WIDESPREAD RAIN CHANGING TO WET SNOW THURSDAY NIGHT INTO TODAY
RESULTED IN ABOUT 1 TO 2 INCHES OF PRECIPITATION. NORTHWEST WINDS
WILL STAY LIGHT TONIGHT AND TOMORROW RANGING 5 TO 10KTS.
MINIMUM RH VALUES TOMORROW AFTERNOON ARE EXPECTED TO RANGE 50 TO
60 PERCENT.
HYDROLOGY
WET SNOW AND RAINFALL COMBINED TO PRODUCE 1-2 INCHES OF
PRECIPITATION ACROSS THE ALY HSA. DUE TO ANTECEDENT DRY
CONDITIONS, FLOODING IS NOT EXPECTED BUT SMALLER CREEKS AND
RIVERS ARE EXPECTED TO RESPOND TONIGHT INTO THE WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES, INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS, PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
UPDATE...
SYNOPSIS...SPECIALE
NEAR TERM...BGM/SPECIALE
SHORT TERM...SPECIALE
LONG TERM...BGM
AVIATION...FRUGIS/OKEEFE
FIRE WEATHER...SPECIALE
HYDROLOGY...SPECIALE
WWW.WEATHER.GOV/ALY
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