692
FXUS61 KALY 261917
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
317 PM EDT SUN JUL 26 2026
WHAT HAS CHANGED
LOWERED TEMPERATURES FOR WEDNESDAY INTO THE UPPER 60S TO LOW 70S GIVEN
INCREASING CONFIDENCE THAT A COASTAL LOW WILL DEVELOP OFF THE
NJ/LONG ISLAND COAST WITH EASTERN NY AND WESTERN NEW ENGLAND
WITHIN THE COOL CONVEYOR BELT AND STRATIFORM RAIN TO THE
NORTHWEST. OTHERWISE, CHANGED SHOWER/THUNDERSTORM WORDING TO
REFLECTED COVERAGE (ISOLATED TO SCATTERED) INSTEAD OF
PROBABILISTIC (SLIGHT CHANCE/CHANCE) FOR TODAY AND TOMORROW AS
VERY LIMITED SHEAR AND WEAK FLOW ALOFT WILL FAVOR PULSE
TYPE/SHORT-LIVED CONVECTION.
KEY MESSAGES
1) ISOLATED TO SCATTERED AND SHORT-LIVED SHOWERS AND THUNDERSTORMS
TODAY INTO TOMORROW, FAVORED IN THE HIGHER TERRAIN AREAS OF THE
SOUTHWEST ADIRONDACKS, NORTHERN/EASTERN CATSKILLS AND SOUTHERN
GREENS.
2) THERE IS A SLIGHT RISK (LEVEL 2 OF 4) FOR EXCESSIVE RAINFALL
RESULTING IN ISOLATED TO SCATTERED FLASH FLOODING FOCUSED
MAINLY SOUTH OF I-90 INTO WESTERN NEW ENGLAND TUESDAY INTO
WEDNESDAY. THIS IS DUE TO MODERATE TO HIGH CONFIDENCE FOR
WIDESPREAD PERIODS OF RAIN AND A CHANCE OF THUNDERSTORMS ACROSS
EASTERN NY AND WESTERN NEW ENGLAND FROM TO A SLOW MOVING COASTAL
STORM.
DISCUSSION
KEY MESSAGE 1...
SURFACE HIGH PRESSURE REMAINS POSITIONED OVER NOVA SCOTIA TODAY
WITH WEAK TROUGHING BUILDING INTO THE NORTHEAST TODAY FROM THE
GREAT LAKES. TEMPERATURES AND DEW POINTS WILL BE VERY SIMILAR TO
YESTERDAY WITH MORNING SUN MIXING WITH AFTERNOON CLOUDS AS WE
REACH OUR CONVECTIVE TEMPERATURES. THE INSOLATION COMBINED WITH
DEW POINTS IN THE UPPER 50S TO AROUND 60 AND COOLING
TEMPERATURES ALOFT UNDER THE INCOMING TROUGH WILL HELP GENERATE
WEAK INSTABILITY; HOWEVER, THE LATEST HREF CONTINUES TO A LOW
CHANCE (UNDER 30-40%) FOR MU CAPE TO EXCEED 1000 J/KG LATE THIS
AFTERNOON FAVORED IN THE HIGHER TERRAIN AREAS. GIVEN WEAK
FORCING AND VERY WEAK SHEAR ALOFT (15KTS OR LESS), EXPECTING
PULSE-TYPE ISOLATED TO WIDELY SCATTERED CONVECTION FAVORED IN
THE SOUTHWEST ADIRONDACKS, NORTHERN/EASTERN CATSKILLS, SOUTHERN
GREENS, AND TACONICS THAT WILL BE SHORT-LIVED AS DOWNDRAFTS FROM
ANY SHOWERS/STORMS QUICKLY CHOKE OFF UPDRAFTS. WHILE PWATS OVER
1" CAN SUPPORT BRIEF HEAVY DOWNPOURS, THE BRIEF DURATION AND
VERY WEAK SHEAR WILL MITIGATE ANY FLOODING OR SEVERE WEATHER
CONCERNS.
MOST SHOWERS/STORMS WILL BE DIURNALLY DRIVEN AND DIMINISH WITH
THE LOSS OF DAYTIME HEATING; HOWEVER, A FEW ISOLATED SHOWERS
MAY LINGERING OVERNIGHT AS SHOWN IN THE LATEST CAMS. THE WEAK
TROUGH FROM TODAY SLIDES INTO NEW ENGLAND TOMORROW BUT CAMS
STILL SUGGEST ANOTHER DAY WITH PULSE-TYPE AND DIURNALLY DRIVEN
CONVECTION GIVEN WESTERLY FLOW ALOFT ADVECTING A SLIGHTLY
WARMER/MORE HUMID AIR MASS INTO THE REGION RESULTING IN SLIGHTLY
HIGHER INSTABILITY (30 TO 60% CHANCE FOR AT LEAST 1000 J/KG OF
SB CAPE). LAPSE RATES ARE STILL WEAK (UNDER 6C/KM) UNDER BROAD
TROUGHING ALOFT BUT CAMS SHOW GREATER COVERAGE OF DIURNALLY
DRIVEN PULSE-TYPE ISOLATED TO SCATTERED CONVECTION, AGAIN
FAVORED IN THE HIGHER TERRAIN AREAS. WEAK SHEAR WILL MITIGATE
ANY FLOODING/SEVERE CONCERNS BUT THERE IS A LOW TO MODERATE
CHANCE FOR BRIEF DOWNPOURS WITHIN ANY STORM.
KEY MESSAGE 2...
THERE IS MODERATE TO HIGH CONFIDENCE IN A COASTAL LOW
DEVELOPING OFF THE NJ/SOUTHERN NEW ENGLAND COAST FOR TUESDAY
INTO WEDNESDAY RESULTING IN PERIODS OF WIDESPREAD RAIN TRACKING
INTO EASTERN NY AND WESTERN NEW ENGLAND. THE GUIDANCE OVER THE
LAST TWO MODEL CYCLES HAS COME INTO BETTER AGREEMENT WITH THE EC
CONVERGING TOWARDS TO THE GFS/CMC SOLUTION WHICH HAVE SHOWN
STRONG UPPER LEVEL DIVERGENCE AHEAD OF AN AMPLIFYING PARENT
SHORTWAVE FROM THE GREAT LAKES RESULTING IN A COASTAL LOW SOUTH
OF LONG ISLAND. HOWEVER, THERE REMAINS UNCERTAINTY IN HOW
QUICKLY THE PARENT TROUGH CLOSES OFF ALOFT WHICH WILL DETERMINE
HOW FAR NORTH THE ENSUING COASTAL LOW FORMS. THE EC REMAINS THE
MOST AGGRESSIVE WITH THE PARENT TROUGH CLOSING OFF THE EARLIEST
RESULTING IN THE COASTAL LOW DEVELOPING FURTHER NORTH CLOSER TO
NYC/LONG ISLAND. THIS WOULD ALLOW THE STRATIFORM RAIN BAND
WITHIN THE DEFORMATION ZONE ON THE NORTH SIDE OF THE LOW TO
TRACK WELL INTO EASTERN NY AND WESTERN NEW ENGLAND. HOWEVER, THE
GFS AND CMC ARE SLIGHTLY DELAYED IN THE PARENT TROUGH
MATURING/CLOSING OFF ALLOWING THE COASTAL TO FORM FURTHER SOUTH
OFF THE NJ COAST, KEEPING THE HEAVIEST RAIN MAINLY SOUTH OF
I-90.
THE EXACT TRACK OF THE LOW WILL DETERMINE WHERE THE HEAVIEST
RAINFALL AMOUNTS OCCURR AND GREATEST CHANCE FOR FLOODING CONCERN BUT
THE INCREASING AGREEMENT ON THE OVERALL SYNOPTIC EVOLUTION
GIVES US MORE CONFIDENCE IN MESSAGING A STRATIFORM, MODERATE
RAIN EVENT. THERE IS GOOD AGREEMENT IN THE WARM CONVEYOR BELT
TAPING INTO GULF AND WESTERN ATLANTIC MOISTURE WITH PWATS
NEARING 2" WRAPPING INTO THE LOW AS IT PIVOTS/SLOWS DOWN ON
WEDNESDAY. THE MODERATE RAINFALL WITHIN THE DEFORMATION ZONE
(AND EVENTUAL TROWAL) LIKELY ALSO PIVOTS AS THE SFC LOW DEEPENS
AND MATURES HEADING INTO COASTAL NEW ENGLAND. THIS RAISES
CONCERNS FOR ISOLATED TO SCATTERED FLASH FLOODING AS THIS REGION
CAN FAVOR EFFICIENT, WARM RAIN PROCESSES PRODUCING HEAVY
RAINFALL RATES. LATEST FLASH FLOOD GUIDANCE SHOWS IT WILL TAKE
MORE THAN 2 TO 3" OF RAIN WITHIN 3 HOURS TO RAISE FLASH FLOODING
CONCERNS THANKS TO DRY ANTECEDENT CONDITIONS BUT A PIVOTING
BAND WITHIN A MOISTURE RICH ENVIRONMENT WITH WEAK INSTABILITY
RAISES SOME CONCERNS. WPC MAINTAINS ITS SLIGHT RISK IN THE
LATEST DAY 3/4 EXCESSIVE RAINFALL OUTLOOK FOCUSED IN WESTERN NEW
ENGLAND AND AREAS MAINLY SOUTH OF I-90 WHERE THE HIGHEST
PROBABILITIES FOR GREATER THAN 2" OF RAIN (40-50%) WITHIN THE
24HR PERIOD BETWEEN 8PM TUES AND 8PM WED EXIST. EASTERLY WINDS
UP TO 850HPA SHOWS THERE WILL LIKELY BE TERRAIN ENHANCEMENT IN
THE EASTERN CATSKILLS AND EASTERN SLOPES OF THE SOUTHERN
GREENS/BERKSHIRES/TACONICS WHERE THE HIGHEST PROBABILITIES ARE
FOR EXCEEDING 2" IN 24 HRS. THERE MAY EVEN BE SOME DOWNSLOPING
IMPACTS ON THE WEST SIDE OF THE TACONICS INTO PORTIONS OF THE
CAPITAL DISTRICT LEADING TO LOWER RAINFALL AMOUNTS. GIVEN THE
TRACK UNCERTAINTIES, THERE IS STILL A LARGE SPREAD IN TOTAL QPF
AMOUNTS BETWEEN THE 25TH AND 75TH PERCENTILE VALUES BUT LATEST
PROBABILITIES SHOW AT LEAST A 60% CHANCE REGIONWIDE FOR 1" OR
MORE OF RAIN SUGGESTING MODERATE TO HIGH CONFIDENCE IN A SOAKING
EVENT FOR MOST OF EASTERN NY/WESTERN NEW ENGLAND STARTING TUES
PM/EVENING LASTING INTO WED NIGHT. LOWEST CHANCES REMAIN IN THE
SOUTHWEST ADIRONDACKS WHICH MAY BE TOO FAR NORTH/WEST OF THE
COASTAL LOW AND HEAVY RAIN BAND. IF CONFIDENCE IN ISOLATED TO
SCATTERED FLASH FLOODING INCREASE, A TARGETED FLOOD WATCH FOR
FLASH FLOODING (RIVER FLOODING IS NOT EXPECTED) MAY BE NEEDED
BUT WE WILL CONTINUE TO WATCH TRENDS AND COLLABORATE WITH
NEIGHBORING WFOS.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
THROUGH 18Z/MON...VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR MUCH
OF THE UPCOMING TAF PERIOD WITH SOME CUMULUS CLOUDS AND PASSING
CIRRUS CLOUDS AT TIMES. ANY SHOWERS THROUGH THIS PERIOD WILL LIKELY
REMAIN WEST OF THE TAF SITES. IF THERE ARE ENOUGH BREAKS IN THE
CLOUDS, PATCHY FOG MAY FORM AT KGFL/KPSF BETWEEN 08-11Z/MON WHERE
BRIEF VSBY REDUCTIONS TO AT LEAST IFR ARE POSSIBLE. WINDS WILL BE
MAINLY LIGHT AT 5 KT OR LESS THROUGH THE PERIOD MAINLY FROM THE
SOUTHEAST TO SOUTHWESTERLY DIRECTIONS.
OUTLOOK...
MONDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: HIGH OPERATIONAL IMPACT. DEFINITE SHRA...TSRA.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE SHRA...TSRA.
WEDNESDAY: HIGH OPERATIONAL IMPACT. DEFINITE SHRA...TSRA.
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
FRIDAY: LOW OPERATIONAL IMPACT. NO SIG WX.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
DISCUSSION...31
AVIATION...33
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