118
FXUS61 KALY 022355
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
755 PM EDT FRI MAY 2 2025
SYNOPSIS
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS DIMINISH
THIS EVENING INTO TOMORROW MORNING BEFORE A COLD FRONT SLOWLY SHIFTS
SOUTHWARD WHICH WILL SUPPORT ADDITIONAL PERIODS OF AFTERNOON SHOWERS
AND SCATTERED THUNDERSTORMS ACROSS MUCH OF THE REGION. PERIODS OF
SHOWERS AND THUNDERSTORMS CONTINUE THROUGH EARLY NEXT WEEK AS A CUT
OFF LOW APPROACHES.
NEAR TERM /THROUGH SATURDAY NIGHT/
KEY MESSAGE:
- ISOLATED STRONG/SEVERE THUNDERSTORMS POSSIBLE (5-15%) FOR
AREAS MAINLY SOUTH/EAST OF ALBANY SATURDAY AFTERNOON/EVENING.
DISCUSSION:
AS OF 701 PM EDT...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE
TO IMPACT EASTERN NY AND WESTERN NEW ENGLAND. LIMITED
INSTABILITY WITH MLCAPES 250-750 J/KG BASED ON THE SPC EMC RAP
MESOANALYSIS HAVE LIMITED THE UPDRAFT HEIGHTS WITH BULK SHEAR OF
25-35 KT. SOME INVERTED-V SIGNATURES IN THE SOUNDINGS FOR A FEW
WIND GUSTS 30-40 MPH BUT THE LOSS OF THE DAYTIME HEATING AND
NOCTURNAL COOLING SHOULD DIMINISH ANY SEVERE THREAT BY 00Z/8 PM
OR SO. WE ARE STILL MONITORING A FEW STRONG STORMS OVER
W-CENTRAL NY AHEAD OF A SHORT-WAVE. SOME CHANGES TO POPS/WEATHER
COVERAGE. ALSO REDUCED THUNDERSTORMS TO ISOLATED AND MADE SOME
CHANGES TO SKY COVER WITH THIS UPDATE.
PREVIOUS NEAR TERM... CLOUDS WILL GIVE WAY TO INCREASING BREAKS
OF SUN THIS AFTERNOON AS A WARM FRONT LIFTS NORTH AND EAST OF
THE REGION. INSOLATION WITHIN A RATHER HUMID AIR MASS
CHARACTERIZED BY DEW POINTS IN THE 50S WILL GENERATE INCREASED
INSTABILITY. LATEST HREF GUIDANCE SHOWS 50 - 70% CHANCE FOR SB
CAPE VALUES TO EXCEED 500 J/KG WITH THE HIGHEST PROBS MAINLY
NORTH AND WEST OF ALBANY BUT PROBABILITIES ARE CAPPED AT JUST 20
- 40% TO EXCEED 1000 J/KG WITH COVERAGE MUCH MORE LIMITED. AS
AN UPPER LEVEL SHORTWAVE AND SFC LOW TRACKS THROUGH ONTARIO, WE
WILL ENTER INTO THE WARM SECTOR AND HIGH TEMPERATURES THIS
AFTERNOON SHOULD REACH INTO THE 70S AND EVEN NEAR 80 IN VALLEY
AREAS. WHILE THE MAIN COLD FRONT REMAINS DISPLACED WELL TO OUR
WEST, A SFC PRESSURE TROUGH FROM WESTERN/CENTRAL NY WILL SHIFT
EASTWARD AND SERVE AS THE PRIMARY FORCING FOR ASCENT. HIGH RES
GUIDANCE SUGGESTS CONVECTION INITIATES INITIALLY IN THE
SOUTHERN/WESTERN ADIRONDACKS BY 17-18 UTC BEFORE SHIFTING SOUTH
AND EASTWARD HEADING TOWARDS I-90 THIS AFTERNOON. GIVEN BROAD
SOUTHWEST FLOW OVER THE EASTERN CONUS WITH A CONVEYOR BELT OF
RATHER STRONG LOW AND MID-LEVEL WINDS, DEEP LAYER SHEAR VALUES
WILL LIKELY BE STRONG ENOUGH TO SUPPORT ORGANIZED CONVECTION,
SHOULD IT DEVELOP, AS 0-6KM SHEAR VALUES REACH 30 - 45KTS. WHILE
INSTABILITY AND SHEAR ARE FAVORABLE ENOUGH TO SUPPORT ORGANIZED
CONVECTION, THE LIFTING MECHANISM LOOKS A BIT WEAK AND THAT MAY
LIMIT THE STRENGTH OF UPDRAFTS. THE GREATEST OVERLAP OF
INSTABILITY AND SHEAR SHOULD BE AREAS NORTH OF I-90 THROUGH MID
AND LATE AFTERNOON, POSSIBLY SHIFTING TO NEAR OR JUST SOUTH OF
I-90 THIS EVENING. THE STORM PREDICTION CENTER MAINTAINS ITS
MARGINAL RISK (LEVEL 1 OF 5) FOR MUCH OF THE REGION FOR SEVERE
THUNDERSTORMS. SINCE LINEAR STORM MODE OR STORM CLUSTERS ARE
FAVORED, DAMAGING WIND GUSTS IS THE PRIMARY HAZARD FROM ANY
STRONG/SEVERE STORMS. STRONGER UPDRAFTS CAN ALSO SUPPORT
MARGINALLY SEVERE HAIL.
STORM COVERAGE WEAKENS AFTER SUNSET WITH MOST SHOWERS/STORMS
DIMINISHING BEFORE MIDNIGHT. THE TRUE SFC COLD FRONT THEN
GRADUALLY SLIDES SOUTH/EAST TOWARDS OUR AREA OVERNIGHT. WITH
MOST OF THE REGION REMAINING AHEAD THE FRONT TONIGHT, MOST CAN
EXPECT MUGGY/MILD CONDITIONS AND WHERE SKIES CAN AT LEAST PARTIALLY
CLEAR MAY SEE SOME PATCHY FOG DEVELOP. THE SOUTHERN/WESTERN
ADIRONDACKS AND WESTERN MOHAWK VALLEY SHOULD TREND COOLER/DRIER
ONCE THE FRONT PUSHES THROUGH TOWARDS SUNRISE.
HEADING INTO SATURDAY, THE INCOMING BOUNDARY STALLS AROUND THE
I-90 CORRIDOR WITH A WARMER/MORE HUMID AIR MASS TO THE SOUTH AND
EAST WITH A SLIGHTLY COOLER AND LESS HUMID AIR MASS THE NORTH
AND WEST. THE CONVEYOR BELT OF RATHER STRONG SOUTHWEST FLOW
REMAINS POSITIONED OVER THE EASTERN CONUS AS A POSITIVELY
TILTED POTENT SHORTWAVE OVER THE TN/MS VALLEY AMPLIFIES INTO A
CUT-OFF LOW. A MOISTURE PLUME WITH PWATS GREATER THAN 1"
CONTINUES TO STREAM FROM THE SOUTHEAST U.S INTO THE NORTHEAST
AND BECOMES FOCUSED ALONG THE STALLED BOUNDARY. AS ADDITIONAL
EMBEDDED SHORTWAVES WITHIN THE SOUTHWEST FLOW TRACK ALONG THE
BOUNDARY, THESE WILL ACT AS THE NECESSARY FORCING MECHANISM TO
RESULT IN PERIODS OF RAIN. THE FIRST HALF OF THE MORNING LOOKS
MAINLY DRY BUT THEN CHANCES FOR RAIN INCREASES BY MID TO LATE
MORNING (10AM - 12PM) AND CONTINUES THROUGH MID-AFTERNOON (2 -
5PM) BEFORE RAIN EXITS FROM WEST TO EAST INTO NEW ENGLAND. ALL
IN ALL, NOT A COMPLETE WASHOUT BUT THERE LIKELY WILL BE A 2 TO 4
HOUR PERIOD OF RAIN. GIVEN THE HIGHER PWATS AND BREAKS OF EARLY
MORNING SUN, MORNING INSOLATION SHOULD AID IN GENERATING SOME
INSTABILITY BUT THE HIGHER DEW POINTS WILL BE POSITIONED IN THE
MID-HUDSON VALLEY AND NW CT. THUS, THE 12 UTC HREF SHOWS 40-60%
CHANCE FOR SB CAPE VALUES TO EXCEED 1000 J/KG IN THESE AREAS
WHILE PROBABILITIES IN AREAS NORTH/WEST OF THE CAPITAL DISTRICT
ARE NEAR 0%. SPC MAINTAINS ITS MARGINAL RISK FOR SEVERE WEATHER
IN OUR SOUTHERN ZONES GIVEN SUFFICIENT SURFACE BASED INSTABILITY
AND HIGHER 0-6KM SHEAR VALUES 30-40KTS THAT CAN SUPPORT SOME
ORGANIZED CONVECTION. SOME MEAGER ELEVATED INSTABILITY VALUES
NORTH/WEST OF ALBANY COULD SUPPORT SOME ISOLATED THUNDERSTORMS
BUT HIGHER CHANCE FOR STORMS REMAINS NEAR AND SOUTH/EAST OF
ALBANY. ANY STORMS COULD PRODUCE BRIEF DOWNPOURS GIVEN THE HIGH
PWATS.
THE STALLED FRONT PRESSES SOUTHWARD HEADING INTO THE MID-HUDSON
VALLEY/NW CT BY 21 - 00 UTC WITH AREAS NORTH/WEST OF THE FRONT
TRENDING DRIER AS COOLER/LESS HUMID FILLS IN BEHIND THE
BOUNDARY. ADDITIONAL SHOWERS/EMBEDDED STORMS LINGER IN THESE
SOUTHERN ZONES THROUGH THE EVENING HOURS AS THE FRONT SHIFTS
SOUTHWARD BUT AS INSTABILITY WANES, STORM COVERAGE SHOULD
DIMINISH. HOWEVER, THE APPROACHING CUT-OFF LOW AMPLIFIES
SATURDAY NIGHT AS IT TRACKS INTO THE OHIO VALLEY LEADING TO
BUILDING HEIGHTS OVER THE NORTHEAST. THIS WILL ALLOW THE FRONT
TO ACTUALLY QUICKLY LIFT NORTHWARD LATE SATURDAY NIGHT INTO
EARLY SUNDAY RESULTING IN ADDITIONAL AREAS OF RAIN AS SOUTHERLY
WINDS ADVECT WARM/MOIST AIR OVER THE BOUNDARY. WE TRENDED POPS
BACK TO LIKELY AFTER MIDNIGHT FROM SOUTH TO NORTH. OTHERWISE,
TEMPERATURES REMAIN MILD IN THE UPPER 40S TO MID-50S WITH
ELEVATED DEW POINTS ALSO SUPPORTING HIGHER HUMIDITY.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
KEY MESSAGES:
- INCREASING CONFIDENCE FOR PERIODS OF RAIN SUNDAY THROUGH
TUESDAY AS A CUT-LOW APPROACHES FROM THE OHIO VALLEY. THERE IS
A 30 TO 60% CHANCE FOR RAINFALL AMOUNTS TO EXCEED 1.5 INCHES
MAINLY FROM THE CAPITAL DISTRICT SOUTHWARD INTO BERKSHIRE AND
LITCHFIELD COUNTY, THE MID-HUDSON VALLEY, AND EASTERN
CATSKILLS.
- POOR DRAINAGE AND URBANIZED FLOODING CAN OCCUR WHERE RAINFALL
REPEATEDLY IMPACTS A GIVEN AREA. HOWEVER, GIVEN RATHER DRY
ANTECEDENT CONDITIONS AND RECENT GREEN-UP, WIDESPREAD FLOODING
IS UNLIKELY. WPC MAINTAINS A MARGINAL RISK FOR EXCESSIVE
RAINFALL DURING THIS PERIOD.
DISCUSSION:
PERIODS OF RAIN CONTINUE INTO SUNDAY AS THE CUT-OFF LOW CONTINUES
TO SHIFT EASTWARD AND UPPER LEVEL DIVERGENCE OUT AHEAD OF IT
ADVANCES INTO THE NORTHEAST. A 40-50KT SOUTHERLY JET AHEAD OF
THE CUT-OFF LOW WILL DIRECT A PWAT PLUME WITH VALUES 1-1.5"
TOWARDS THE STALLED BOUNDARY POSITIONED NEAR OR JUST NORTH OF
I-90 HELPING MAINTAIN OVERRUNNING AND PERIODS OF RAIN FOCUSED
HERE THROUGH MUCH OF THE DAY. THUS, WE CONTINUE TO MESSAGE
LIKELY AND CATEGORICAL POPS (60 - 90% CHANCE OF RAIN) THROUGH
THE DAY FOR THESE AREAS WHILE THE MID-HUDSON VALLEY AND NW CT
SHOULD SQUEEZE OUT MORE DRY TIME AS SOME MID-LEVEL DRY AIR FILLS
IN BEHIND THE LIFTING FRONT (LOWER POPS AT 25 - 40%). BETWEEN
THE CLOUDS AND PERIODS OF RAIN, TEMPERATURES REMAIN SEASONABLE
IN THE 60S WITH UPPER 50S IN THE SOUTHERN/WESTERN ADIRONDACKS.
WARMER IN THE LOW 70S IN SOUTHERN ZONES. ELEVATED DEW POINTS
WILL MAKE IT FEEL NOT AS COOL. THE STALLED BOUNDARY BECOMES
LESS DEFINED SUNDAY NIGHT AND GRADUALLY SINKS SOUTHWARD AS HIGH
PRESSURE BUILDS INTO THE CANADIAN MARITIME.
OUR WET PATTERN CONTINUES INTO MONDAY AND TUESDAY AS THE CUT-
OFF LOW CONTINUES TO SHIFT EASTWARD. THIS WILL ALLOW STRONGER
UPPER LEVEL DIVERGENCE AND ENHANCED FORCING FOR ASCENT AHEAD OF
IT TO BECOME BETTER POSITIONED OVERHEAD MAINTAINING ROUNDS OF
RAIN AND SOME EMBEDDED THUNDERSTORMS. THE SOUTHERLY JET ALSO
CONTINUES TO DIRECT THE MOISTURE PLUME INTO THE REGION WITH THE
NAEFS SHOWING PWATS AND IVT VALUES RANKING IN THE 90TH
PERCENTILE OF THE MODEL CLIMATOLOGICAL SUPPORTING CONFIDENCE FOR
THIS WET STRETCH. WE THEREFORE MAINTAINED 50 - 80% POPS FOR
MOST OF EASTERN NY AND WESTERN NEW ENGLAND FOR THESE TWO DAYS
WITH THE HIGHEST POPS ALONG AND SOUTH OF I-90 CLOSER TO THE
MOISTURE PLUME. PROBABILISTIC GUIDANCE SHOWS 30 - 60% CHANCE FOR
RAINFALL AMOUNTS DURING THIS 48 HOUR PERIOD TO EXCEED 1 INCH AND
JUST 10 - 20% TO EXCEED 2 INCHES AGAIN HIGHEST PROBABILITIES
SOUTH OF I-90. WPC MAINTAINS A MARGINAL RISK OVER THE NORTHEAST
IN ITS EXCESSIVE RAINFALL OUTLOOK (ERO) FOR THESE TWO DAYS BUT
DECIDED TO HOLD OFF ON ANY UPGRADES TO A SLIGHT RISK GIVEN THIS
A DAY 5 OUTLOOK AND ANTECEDENT CONDITIONS OVER THE PAST FEW
WEEKS HAVE BEEN RATHER DRY. WE WILL CONTINUE TO EVALUATE MODEL
AND QPF TRENDS OVER THE COMING DAYS AND COLLABORATE ANY
NECESSARY CHANGES TO THE ERO. CONCEPTUAL MODELS FROM PAST CSTAR
AND LOCAL RESEARCH SHOWS THAT CUT-OFF LOW AND MOISTURE RICH
ENVIRONMENTS TYPICALLY INCREASE THE POTENTIAL FOR AREAS OF
MODERATE TO HEAVY RAIN TO TRAIN OR REPEATEDLY IMPACT A GIVEN
AREA ESPECIALLY WHEN PWATS ARE HIGH AND THE VERTICAL SHEAR
PROFILES BECOME STRONG/UNIDIRECTIONAL. SUCH CASES CAN EASILY
RESULT IN POOR DRAINAGE OR URBANIZED FLOODING AND IN MORE
EXTREME SITUATIONS CAN LEAD TO LOCALIZED FLASH FLOODING. GIVEN
WE ARE STILL 3-4 DAYS AWAY, CONFIDENCE IS STILL TOO LOW TO KNOW
IF SUCH A FAVORABLE SET-UP WILL BE PLACE MONDAY AND TUESDAY BUT
WE WILL MAINTAIN A WATCHFUL EYE IN THE COMING DAYS.
LONG TERM /TUESDAY THROUGH FRIDAY/
KEY MESSAGE:
- UNSETTLED WEATHER AND ABOVE NORMAL TEMPS WEDNESDAY GIVE WAY TO
COOLER AND DRIER CONDITIONS THURSDAY.
DISCUSSION:
CUTOFF LOW SHOULD BE CENTERED NEAR NY/PA TO START THE LONG TERM
PERIOD, WHICH WILL HELP KEEP THE REGION IN AN UNSETTLED WEATHER
PATTERN. AMPLE FORCING WITH CVA AROUND THE LOW, DIFFLUENCE ALOFT AND
AMPLE MOISTURE (PWATS AROUND 1.00") WILL KEEP CHANCES OF
SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. TEMPERATURES LOOK
TO HOLD NEAR TO ABOVE NORMAL WITH SOUTHERLY FLOW REMAINING
FAVORED, WITH LATEST NBM KEEPING HIGHS IN THE UPPER 60S TO LOW
70S.
THANKFULLY, RELIEF FROM THE RAIN CHANCES WILL ARRIVE WEDNESDAY NIGHT
AND THURSDAY AS THE CUTOFF LOW PHASES WITH A STRONGER SHORTWAVE
DIVING SOUTHEAST OUT OF ONTARIO INTO THE NORTHEAST. THIS WILL ALSO
SWEEP A COLD FRONT THROUGH THE REGION, WITH COOLER AND DRIER AIR
ARRIVING FOR THE DAYTIME THURSDAY AND LASTING INTO THE WEEKEND.
HIGHS THURSDAY SHOULD BE BACK NEAR NORMAL, RANGING FROM THE MID 50S
TO UPPER 60S.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
THROUGH 00Z/SUN...A PREFRONTAL DISTURBANCE IN THE WARM SECTOR
AHEAD OF A COLD FRONT HAS PRODUCED ISOLATED/WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS LATE THIS PM INTO TONIGHT WITH LITTLE
IMPACT ON THE TAF SITES. CONDITIONS ARE VFR AT
KGFL/KALB/KPOU/KPSF. WE DID KEEP TEMPO GROUPS FOR MVFR VSBYS
WITH SHOWERS FOR KALB/KPSF BETWEEN 02Z-06Z/SAT, BUT STAYED VFR
WITH SCT-BKN CLOUD BASES 5-8 KFT AGL FOR KGFL/KPOU. SOME
LOWERING OF THE CLOUDS WILL OCCUR OVERNIGHT WITH VFR CIGS 3.5-5
KFT AGL AT KPOU/KPSF/KGFL TOWARDS 09Z/SAT AND HIGH MVFR AT KALB
AT 3 KFT AGL. BASES WILL GRADUALLY LOWER TO HIGH MVFR LEVELS
DURING THE LATE MORNING, AS A COLD FRONT APPROACHES AND SHOWERS
INCREASE. EXPECT MVFR CIGS/VSBYS FOR KALB/KPSF NORTHWARD WITH
VFR CONDITIONS PERSISTING AT KPOU IN THE LATE MORNING INTO THE
EARLY AFTERNOON. PROB30 GROUPS WERE USED TO BRING SOME SCATTERED
THUNDERSTORMS IN ALL THE TAF SITES ESPECIALLY 20Z/SAT TO
00Z/SUN AHEAD OF THE COLD FRONT WITH IFR/MVFR CONDITIONS.
THE WINDS WILL BE WEST TO SOUTHWEST AT 10 KT OR LESS EARLY
TONIGHT AND WILL BECOME LIGHT AND VARIABLE AT 4 KT OR LESS TO
CALM OVERNIGHT. THE WINDS WILL VEER FROM THE SOUTH/SOUTHWEST AT
5-10 KT IN THE LATE MORNING INTO THE AFTERNOON TO THE
NORTH/NORTHWEST TO THE NORTH/NORTHEAST AT 10 KT OR LESS.
OUTLOOK...
SATURDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA.
SUNDAY: HIGH OPERATIONAL IMPACT. DEFINITE SHRA.
SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
MONDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA.
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA.
TUESDAY: HIGH OPERATIONAL IMPACT. DEFINITE SHRA...TSRA.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...SPECIALE/WASULA
NEAR TERM...SPECIALE/WASULA
SHORT TERM...SPECIALE
LONG TERM...SPECK
AVIATION...WASULA
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