127
FXUS61 KALY 021103
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
703 AM EDT SUN AUG 2 2026
WHAT HAS CHANGED
INCREASED WINDS FOR MONDAY AS WINDS SHIFT TO THE NORTHWEST IN
THE WAKE OF THE INCOMING COLD FRONT AND BECOME RATHER BREEZY
WITH GUSTS UP TO 25-30KTS. OTHERWISE, NO MAJOR CHANGES FOR THE
HEAVY RAIN POTENTIAL FOR TONIGHT INTO TOMORROW BUT THE MARGINAL
SEVERE THUNDERSTORM RISK FOR TOMORROW WAS EXPANDED INTO THE
CAPITAL DISTRICT, MOST OF WESTERN NEW ENGLAND AND INTO PARTS OF
THE UPPER HUDSON VALLEY.
KEY MESSAGES
1) A SLOW MOVING COLD FRONT WILL RESULT IN PERIODS OF SHOWERS
AND THUNDERSTORMS ACROSS THE ENTIRE REGION TONIGHT INTO MONDAY.
HEAVY RAINFALL RATES CAN RESULT IN ISOLATED TO SCATTERED FLASH
FLOODING, WITH AREAS THAT SAW HIGH RAINFALL AMOUNTS RECENTLY
MOST SUSCEPTIBLE TO RENEWED FLOODING.
2) THERE IS A MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE
THUNDERSTORMS TOMORROW AFTERNOON FOR ALL OF EASTERN NY AND
WESTERN NEW ENGLAND, EXCEPT THE SOUTHWEST ADIRONDACKS AND
MOHAWK VALLEY, WITH DAMAGING WINDS THE PRIMARY HAZARD.
DISCUSSION
KEY MESSAGE 1...
LATEST SATELLITE IMAGERY SHOWS A VERTICALLY STACKED CUT-OFF LOW
IN THE OHIO VALLEY, APPROACHING SHORTWAVE INTO THE GREAT LAKES
AND STRONG RIDGING OFF SHORE SUPPORTING A DEEP FETCH MOISTURE
FROM THE GULF AND WESTERN ATLANTIC UP THE EAST COAST. THIS
MERIDIONALLY FLOW PATTERN WILL RESULT IN A HIGHLY MOISTURE RICH
AND HUMID ENVIRONMENT ACROSS THE NORTHEAST THROUGH TOMORROW AS
ANOMALOUSLY STRONG V-WIND COMPONENTS ALLOW PWATS TO SURGE
IMPRESSIVELY TOWARDS 2-2.25" OR 3 STANDARD DEVIATIONS ABOVE
NORMAL PER THE ENS STANDARD ANOMALIES. AS THE NORTHERN STREAM
SHORTWAVE TRACKS INTO THE GREAT LAKES TODAY, IT LOOKS TO SLOW
DOWN AS IT INTERACTS WITH THE CLOSED LOW AND AMPLIFY AS IT TAKES
ON A NEGATIVE TILT THROUGH TONIGHT. WITH THIS SHORTWAVE DISPLACED
WELL TO OUR WEST AND WEAK SUBSIDENCE STILL OVERHEAD FROM THE
OFF SHORE RIDGE, THE MOISTURE AND HEAVY RAIN AXIS LOOKS TO BE
FOCUSED MORE IN THE SAINT LAWRENCE RIVER VALLEY AND SOUTHERN
CANADA MOST OF TODAY. HOWEVER, AS THE LEADING EDGE OF THE LOW
AND MID-LEVEL SOUTHERLY JET AND IMPRESSIVE PWAT PLUME NOSES
INTO THE NORTHEAST LATE THIS MORNING INTO THE AFTERNOON, HIGH
RES GUIDANCE SHOWS A FEW SCATTERED SHOWERS AND WEAK
THUNDERSTORMS TRACKING INTO THE SOUTHWEST ADIRONDACKS AND
WESTERN MOHAWK VALLY. WARM/MOIST MID-LEVELS WILL KEEP LAPSE
RATES POOR, LIMIT INSTABILITY AND THEREFORE LIKELY PREVENT ANY
SEVERE STORMS.
THE HEAVY RAIN/MOISTURE AXIS FROM THE SAINT LAWRENCE RIVER
VALLEY SHIFTS EASTWARD TONIGHT INTO EASTERN NY AND WESTERN NEW
ENGLAND AS THE NORTHERN STREAM TROUGH TAKES ON A NEGATIVE TILT.
THE FAVORABLE OVERLAP OF STRONG FORCING FOR ASCENT, WEAK
INSTABILITY AND STRENGTHENING SOUTHERLY FLOW THROUGH A DEEP
LAYER WITHIN A HIGHLY MOISTURE RICH ENVIRONMENT WILL SUPPORT
HIGH RAINFALL RATES. THE LATEST PMM FROM THE HREF SHOWS A 30 -
50% CHANCE FOR OVER 1" OF RAIN IN 3HRS AND EVEN A SMALL AREA
WITH A 10% CHANCE OF OVER 3" OF RAIN IN 3HRS DURING THE 06 - 15
UTC MONDAY WINDOW. THE HIGHEST PROBABILITIES AND QPF MAXIMA
AREAS ARE FAVORED IN THE MID-HUDSON VALLEY INTO WESTERN MA AND
NW CT, SIMILAR TO THE SLIGHT RISK DAY 2 ERO PLACEMENT. WHILE
BANDS OF HEAVY RAIN SHOULD BE RATHER PROGRESSIVE, THE
UNIDIRECTIONAL FLOW THROUGH A DEEP LAYER SUGGEST POTENTIAL FOR
HEAVY RAIN TO REPEATEDLY IMPACT A GIVEN AREA TONIGHT INTO MONDAY
MORNING. WITH 1HR AND 3HR FLASH FLOOD GUIDANCE VALUES GENERALLY
1.75 - 2.5" HERE, IT WILL TAKE REPEATEDLY ROUNDS OF HEAVY RAIN
TO RAISE CONCERNS FOR ISOLATED TO SCATTERED FLASH FLOODING;
HOWEVER, THE IMPRESSIVE MOISTURE ANOMALIES AND FAVORABLE WARM
RAIN PROCESSES SUPPORTING HIGH RAINFALL RATES MEANS WE WILL
NEED TO CLOSELY MONITOR RAINFALL TRENDS OVERNIGHT INTO MONDAY
MORNING.
THE MAIN MOISTURE/HEAVY RAIN AXIS SHIFTS INTO NEW ENGLAND
MONDAY MORNING AS THE PARENT SHORTWAVE CUTS-OFF AND PUSHES
EASTWARD. HOWEVER, THERE IS INCREASING CONFIDENCE FOR A LINE OF
STRONG TO EVEN SEVERE STORMS TO DEVELOP AHEAD OF THE SFC
BOUNDARY AS IT TRACKS EASTWARD MONDAY AFTERNOON. STORMS CAN
CERTAINLY PRODUCE ADDITIONAL HEAVY DOWNPOURS AS INSTABILITY
INCREASES ON MONDAY AND ANY AREAS THAT BECOME SATURATED FROM
THE OVERNIGHT/MONDAY A.M RAIN WILL BE VULNERABLE TO ADDITIONAL
LOCALIZED FLOODING. BETWEEN 8PM SUN AND 8PM MON, THE LATEST NBM
PROBABILISTIC GUIDANCE STILL SHOWS A 40 TO 70% CHANCE FOR 24HR
RAINFALL AMOUNTS TO EXCEED 1" WITH EVEN A 20 TO 35% CHANCE FOR
OVER 2". THE HIGHEST PROBABILITIES ARE FAVORED IN THE DAY 2 ERO
SLIGHT RISK (LEVEL 2 OF 4) AREA IN THE MID-HUDSON VALLEY AND NW
CT; HOWEVER, THESE AREAS MAINLY MISSED OUT ON THE RECORD
RAINFALL LAST WEEK SO DECIDED TO HOLD OFF ON A FLOOD WATCH IN
COLLABORATION WITH NEIGHBORING WFOS. A MARGINAL RISK (LEVEL 1 OF
4) IN THE DAY 2 ERO EXTENDS FURTHER NORTH/WEST INTO MOST OF
EASTERN NY WHERE ANY FLASH FLOODING SHOULD BE ISOLATED.
KEY MESSAGE 2...
AFTER THE MAIN AREA OF RAIN EXITS INTO NEW ENGLAND MONDAY
MORNING, THERE MAY BE A BRIEF OPPORTUNITY FOR FILTERED SUN TO
HELP DESTABILIZE THE ATMOSPHERE BEFORE THE MAIN TROUGH AXIS
SWINGS THROUGH THE REGION MONDAY AFTERNOON. THE BEST CHANCE FOR
THIS LOOKS TO BE FROM THE CAPITAL DISTRICT/UPPER HUDSON VALLEY
EASTWARD INTO WESTERN NEW ENGLAND WHERE THERE WILL BE A FEW HOUR
DELAY BETWEEN THE EXITING MORNING RAIN AND THE SFC BOUNDARY.
GIVEN THE HIGH DEW POINTS/VERY HUMID AIR MASS IN PLACE, ANY
INSOLATION WILL QUICKLY INCREASE SFC BASED INSTABILITY. HOWEVER,
FORECAST SOUNDINGS SHOW A RATHER MOIST COLUMN SO MID-LEVEL LAPSE
RATES ARE RATHER POOR. EVEN STILL, THE FAST FLOW ALOFT AND A
VEERING WIND PROFILE IN THE LOW-LEVELS WILL SUPPORT BOTH
DIRECTIONAL AND SPEED SHEAR WITH 0-6KM SHEAR VALUES NEARING
40KTS. THIS REGIME LOOKS TO FAVOR WET MICROBURSTS LEADING TO
LOCALIZED DAMAGING WINDS FROM ANY STORMS THAT CAN GROW UPSCALE
WITH SUSTAINED UPDRAFTS. SPC EXPANDED THE MARGINAL RISK IN ITS
DAY 2 OUTLOOK TO MESSAGE DAMAGING WIND POTENTIAL FROM ANY SEVERE
STORMS. GIVEN UNCERTAINTIES ON HOW MUCH INSOLATION CAN OCCUR
BEFORE THE SFC BOUNDARY ARRIVES, A MARGINAL RISK FOR ISOLATED
SEVERE STORMS SEEMS MOST APPROPRIATE. THE SFC BOUNDARY EXITS
INTO NEW ENGLAND BY OR SHORTLY AFTER 00 UTC TUES, ENDING THE
SEVERE WEATHER THREAT.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
THROUGH 12Z MONDAY... VFR CONDITIONS PREVAIL ACROSS ALL
TERMINALS TO START OFF THIS TAF PERIOD, WITH SOUTHERLY WINDS AND
SOME GUSTY WINDS UP TO 15-18 KTS AT KALB AND KPOU. SOME
LINGERING LOW CLOUDS AND ISOLATED SHOWERS COULD BRING CIGS DOWN
TO MVFR LATE THIS MORNING INTO THIS AFTERNOON AT KGFL AND KPSF,
OTHERWISE HIGH CLOUDS WILL DOMINATE ACROSS ALL TERMINALS THROUGH
THIS AFTERNOON. WINDS ARE ALSO EXPECTED TO STRENGTHEN
THROUGHOUT THE DAY TODAY, WITH GUSTS EXPECTED TO REACH UP TO
AROUND 20-25 KTS AT ALL TERMINALS THROUGH THIS EVENING.
SCATTERED SHOWERS WILL BEGIN TO MOVE INTO THE REGION THIS
EVENING AS CIGS BEGIN TO LOWER, BRINGING PERIODS OF MVFR VIS AND
CIGS TO ALL TERMINALS. THIS RAIN WILL BECOME MORE WIDESPREAD
AFTER 00Z, CAUSING FURTHER REDUCTION IN CIG/VIS CATEGORIES AT
ALL TERMINALS, WITH THE POTENTIAL OF IFR VIS AT KGFL AND KPSF,
AND IFR CIGS AT KGFL, KPOU, AND KPSF. KALB WILL ALSO EXPERIENCE
THESE REDUCTIONS, ALTHOUGH VIS OR CIGS ARE NOT EXPECTED TO DROP
BELOW MVFR AT THIS TIME, WHICH MAY CHANGE WITH FUTURE TAF
CYCLES.
OUTLOOK...
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
DISCUSSION...27/31
AVIATION...23
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