309
FXUS61 KALY 282349
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
749 PM EDT TUE JUL 28 2026
WHAT HAS CHANGED
AXIS OF HEAVIEST QPF HAS SHIFTED EAST INTO THE HIGH TERRAIN OF
WESTERN NEW ENGLAND. ACCORDINGLY, THE FLOOD WATCH HAS BEEN EXPANDED
TO INCLUDE ALL OF SOUTHERN VT. WPC HAS ALSO PLACED THIS AREA INTO
THE MODERATE RISK ERO TODAY, AND HAS ADDED A MODERATE RISK ERO
TOMORROW FOR WESTERN MA AND SOUTHERN VT. FINALLY, WILL MENTION THE
POTENTIAL FOR A FEW STRONGER STORMS WITH DAMAGING WIND GUSTS THIS
AFTERNOON AND EVENING.
KEY MESSAGES
1) MULTIPLE ROUNDS OF SHOWERS/THUNDERSTORMS WILL PRODUCE HEAVY RAIN
THIS AFTERNOON THROUGH WEDNESDAY, ESPECIALLY AREAS SOUTH OF I-90 AND
IN WESTERN NEW ENGLAND WHERE A FLOOD WATCH IS IN EFFECT FOR FLASH
FLOODING THROUGH WEDNESDAY AFTERNOON.
2) DESPITE AREAS OF HEAVY RAINFALL, CURRENT RIVER FORECASTS SUGGEST
THREAT FOR RIVER FLOODING IS LOW AT THIS TIME. HOWEVER, IF ANY
OF THE HIGHER-END RAINFALL TOTALS ARE REALIZED THEN ISOLATED
MINOR RIVER FLOODING WOULD BE POSSIBLE.
DISCUSSION
KEY MESSAGE 1... AS OF 2:55 PM EDT...CURRENT SFC ANALYSIS SHOWS
AN ELONGATED SFC LOW LOCATED OVER WESTERN NY AND PA. THIS LOW
HAS DEVELOPED IN RESPONSE TO AN ANOMALOUS UPPER TROUGH CURRENTLY
SEEN ON GOES 16 WV IMAGERY OVER THE GREAT LAKES. AS THIS UPPER
LOW CLOSES OFF THIS EVENING AND AN UPPER SHORTWAVE TRACKS AROUND
ITS SOUTHERN PERIPHERY, A COASTAL LOW WILL FORM OFF THE MID
ATLANTIC COAST AND EVENTUALLY TRACK NEAR OR OVER LONG ISLAND
TONIGHT INTO TOMORROW, BRINGING PERIODS OF HEAVY RAIN AND
THUNDERSTORMS TO THE REGION. THE SFC LOW AND ULL BOTH SIT AND
SPIN OVERHEAD THROUGH THURSDAY, BRINGING CONTINUED SHOWERS TO
THE REGION UNDER THE UPPER-LEVEL DEFORMATION AXIS.
CURRENT CIRA ALPW SATELLITE IMAGERY SHOWS DEEP MOISTURE SURGING
INTO THE REGION THIS AFTERNOON AHEAD OF THE APPROACHING SFC LOW
AIDED BY A STRENGTHENING SOUTHERLY LLJ THAT WILL EVENTUALLY
TURN TO THE SOUTHEAST TONIGHT AND THE EAST TOMORROW. PWATS
INCREASE TO 1.75 TO 2.0 INCHES THIS AFTERNOON INTO TOMORROW,
WHICH IS ANOMALOUS BUT NOT EXCEPTIONALLY SO FOR LATE JULY. WARM
CLOUD DEPTHS OF AROUND 12 KFT WILL HELP TO PROMOTE EFFICIENT
WARM RAIN PROCESSES, WHILE UNIDIRECTIONAL FLOW WILL PROMOTE
BACKBUILDING AND TRAINING OF STORMS. MEAN CLOUD LAYER WINDS OF
ONLY AROUND 15 KT WITH SLOWER MBE VECTORS WILL ALSO SUPPORT SLOW
STORM MOTIONS. THE STRENGTH OF THE FORCING WILL BE QUITE
UNUSUAL, WITH MSLP AND UPPER-LEVEL HEIGHT ANOMALIES AS LOW AS
3-4 STD DEV BELOW NORMAL OVERLAPPING THIS VERY MOIST ATMOSPHERE.
MODEL FORECAST SOUNDINGS CONTINUE TO SHOW A TALL, SKINNY CAPE
PROFILE, WITH AT LEAST SOME ELEVATED INSTABILITY THROUGH
WEDNESDAY EVENING THAT WILL SUPPORT THE POTENTIAL FOR HEAVY
DOWNPOURS. SO, ALL SIGNS ARE THERE FOR VERY HEAVY RAIN.
THE LOCATION OF THE HEAVIEST RAINFALL AMOUNTS WILL DEPEND ON
EXACTLY WHERE TRAINING AND BACKBUILDING OF CONVECTION SETS UP,
WHICH IS STILL HARD TO DETERMINE SEVERAL HOURS OUT FROM THE
HEAVIEST RAIN. THAT SAID, WE HAVE SEEN A FAIRLY LARGE EASTWARD
SHIFT WITH NUMERICAL GUIDANCE IN THE AXIS OF HEAVIEST QPF WITH
THIS MORNING'S 12Z RUNS. OVER THE PEAKS AND EAST-FACING SLOPES
OF THE BERKSHIRES, E/SE UPSLOPE ENHANCEMENT WILL LIKELY LEAD TO
SOME RAINFALL TOTALS OF UP TO 3-5", WITH SOME HIGHER AMOUNTS
LOCALLY UP TO 7" NOT OUT OF THE QUESTION. RAINFALL AMOUNTS HAVE
TRENDED DOWN SLIGHTLY FOR THE MID HUDSON VALLEY, AND THERE MAY
ACTUALLY BE SOME DOWNSLOPING HERE OFF OF THE HIGH TERRAIN, BUT
THE CATSKILLS ARE STILL EXPECTED TO SEE UP TO 3-5" OF RAIN WITH
LOCALLY HIGHER AMOUNTS UP TO 6-7" AS WELL. RAINFALL RATES THIS
AFTERNOON AND TONIGHT ARE LIKELY TO EXCEED 1-2" PER HOUR AT
TIMES AND MAY EVEN BRIEFLY REACH 3" PER HOUR FOR A FEW AREAS IN
THE FLOOD WATCH. RAINFALL RATES TOMORROW DON'T LOOK QUITE AS
HIGH AS TODAY, BUT COULD STILL EXCEED 1" PER HOUR ESPECIALLY IN
SOUTHERN VT AND THE BERKSHIRES. WITH THIS RAIN TOMORROW FALLING
ON ALREADY SATURATED SOILS, THERE WILL BE A CONTINUED FLASH
FLOOD THREAT INTO TOMORROW.
GIVEN THE CHANGES IN EXPECTED QPF, WE HAVE EXPANDED THE FLOOD WATCH
INTO SOUTHERN VT IN COORDINATION WITH WFO BTV. WPC HAS ALSO EXPANDED
THE DAY 1 MODERATE RISK ERO INTO THIS AREA, AND HAS INTRODUCED A DAY
2 MODERATE RISK ERO FOR MUCH OF OUR WESTERN NEW ENGLAND AREAS WHILE
MAINTAINING THE MARGINAL TO SLIGHT FOR EASTERN NY. IF SOME OF THESE
HIGH-END RAINFALL AMOUNTS ARE REALIZED, THEN NUMEROUS INSTANCES OF
FLASH FLOODING AND SOME SIGNIFICANT FLASH FLOODING WILL BE POSSIBLE.
LOCAL RESEARCH HAS SHOWN THAT MANY OF OUR SUMMER DAYS FEATURING
WIDESPREAD FLASH FLOODING ARE ASSOCIATED WITH AN UPPER LOWS LIKE THE
ONE THAT WILL BE OVERHEAD TONIGHT AND WEDNESDAY, SO THIS HAS ADDED
TO OUR CONFIDENCE IN THE POTENTIAL FOR FLASH FLOODING. WHILE MANY
AREAS HAVE BEEN QUITE DRY RECENTLY AND COULD USE SOME RAIN, THIS
LOOKS LIKE A CLASSIC CASE OF TOO MUCH RAIN TOO QUICKLY.
SOME LINGERING SHOWERS ARE EXPECTED THURSDAY, BUT ARE NOT EXPECTED
TO RESULT IN ADDITIONAL FLOODING. A DRY PERIOD IS THEN EXPECTED FOR
FRIDAY AND SATURDAY, WITH INCREASING CHANCES FOR RAIN AGAIN SUNDAY
OR MONDAY AHEAD OF THE NEXT APPROACHING UPPER TROUGH AND COLD
FRONTAL SYSTEM.
FINALLY, WILL MENTION A LOW THREAT FOR SOME STRONGER STORMS THIS
AFTERNOON. LOW-LEVEL AND DEEP-LAYER WIND SHEAR ARE WEAK, BUT LATEST
SPC MESOANALYSIS SHOWS 1000-1500 J/KG OF MLCAPE ACROSS THE REGION,
WITH THE HIGHEST VALUES SOUTH AND EAST OF THE CAPITAL DISTRICT WHERE
THERE HAVE BEEN MORE BREAKS OF SUN THIS MORNING. THEREFORE, WE CAN'T
RULE OUT A FEW INSTANCES OF WET MICROBURSTS LEADING TO DAMAGING
WINDS WITH ANY TALLER STORMS THIS AFTERNOON. HOWEVER, THREAT FOR
SEVERE WEATHER IS MUCH LESS OF A CONCERN THAN THAT FOR HEAVY RAIN
AND FLASH FLOODING.
KEY MESSAGE 2...LATEST HEFS (ENSEMBLE RIVER FORECASTS)
CONTINUE TO SHOW A LOW (GENERALLY <10-15%) CHANCE FOR MAIN STEM
RIVER FLOODING WITH THIS EVENT, LIKELY DUE TO ANTECEDENT DRY
CONDITIONS AND RAINFALL DEFICITS. THAT SAID, WITHIN-BANK RISES
ON MOST RIVERS, CREEKS, AND STREAMS ARE EXPECTED. IF SOME OF THE
HIGHER END RAINFALL TOTALS ARE REALIZED (5-7"), THEN SOME MINOR
RIVER FLOODING WOULD BE POSSIBLE. THE BEST CHANCE OF SEEING
THESE RAINFALL AMOUNTS IS IN THE EASTERN CATSKILLS AND HIGHER
TERRAIN OF WESTERN NEW ENGLAND.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
THROUGH 00Z THURSDAY... WIDESPREAD RAIN AND SCATTERED
THUNDERSTORMS CONTINUE ACROSS ALL TERMINALS THROUGHOUT THIS
EVENING, YIELDING MVFR AND IFR VIS AND CIGS TO START OFF THIS
TAF PERIOD. PERIODS OF HEAVY RAINFALL COULD BRING DOWN VIS TO 1
SM AND LOWER THROUGHOUT THE OVERNIGHT PERIOD. KGFL IS EXPECTED
TO SEE THE GREATEST REDUCTION IN VIS OVERNIGHT AND INTO THE
EARLY MORNING, WITH THE POTENTIAL OF FOG FORMATION ON THURSDAY.
RAIN WILL START TO BECOME MORE SCATTERED ON THURSDAY MORNING AND
AFTERNOON AND CONDITIONS WILL GRADUALLY IMPROVE THROUGHOUT THAT
TIME. HOWEVER, CIGS AND VIS ARE EXPECTED TO REMAIN MVFR AND IFR
THROUGH THE END OF THE TAF PERIOD.
SOUTHERLY TO SOUTHEASTERLY WINDS WITH MODERATE GUSTS PREVAIL AT
THE START OF THIS PERIOD AT ALL TERMINALS EXCEPT FOR KALB.
WINDS WILL GRADUALLY WEAKEN THROUGHOUT THE OVERNIGHT PERIOD AND
BEGIN TO VEER MORE EASTERLY, WITH WINDS PREVAILING OUT OF THE
EAST TO NORTHEAST THROUGHOUT THURSDAY AT ALL TERMINALS.
OUTLOOK...
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
ALY WATCHES/WARNINGS/ADVISORIES
CT...FLOOD WATCH THROUGH WEDNESDAY EVENING FOR CTZ001-013.
NY...FLOOD WATCH THROUGH WEDNESDAY EVENING FOR NYZ058>061-063>066.
MA...FLOOD WATCH THROUGH WEDNESDAY EVENING FOR MAZ001-025.
VT...FLOOD WATCH THROUGH WEDNESDAY EVENING FOR VTZ013>015.
DISCUSSION...35
AVIATION...23
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