826
FXUS61 KALY 220621
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
221 AM EDT SAT AUG 22 2026
WHAT HAS CHANGED
SPC EXPANDED THE MARGINAL RISK FOR ISOLATED SEVERE WEATHER
(LEVEL 1 OF 5) ON SUNDAY TO NOW COVER MOST OF EASTERN NY AND
WESTERN NEW ENGLAND.
KEY MESSAGES
1) AREAS OF SHOWERS AND THUNDERSTORMS ARRIVE LATE TONIGHT AND
CONTINUE INTO SUNDAY AFTERNOON. THERE IS A MARGINAL RISK (LEVEL
1 OF 5) FOR ISOLATED SEVERE THUNDERSTORMS ACROSS MUCH OF EASTERN
NY AND WESTERN NEW ENGLAND SUNDAY AFTERNOON.
2) ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE MONDAY
AND TUESDAY, ESPECIALLY NEAR AND NORTH OF I-90, WITH TEMPERATURES
REMAINING SLIGHTLY COOLER THAN NORMAL.
DISCUSSION
KEY MESSAGE 1...
BROAD TROUGHING CONTINUES DEVELOPING UPSTREAM OVER THE UPPER
GREAT PLAINS INTO THE GREAT LAKES TODAY WHILE THE NORTHEAST
REMAINS ON THE WEST SIDE OF LARGE SCALE RIDGING POSITIONED OVER
THE WESTERN ATLANTIC. WHILE HEIGHT FALLS SLOWLY CREEP EASTWARD
INTO WESTERN NY TODAY, EASTERN NY AND WESTERN NEW ENGLAND
REMAINS UNDER THE INFLUENCE OF WEAK SUBSIDENCE WHICH WILL KEEP
US DRY. A WEAK SFC LOW MEANDERING IN NEW ENGLAND COMBINED WITH
SOUTHWEST FLOW ALOFT WILL KEEP A CIRRUS CANOPY OVER AREAS ALONG
AND EAST OF THE HUDSON WHILE AREAS TO THE WEST ENJOY MORE
SUNSHINE. EAST-SOUTHEAST WINDS AT THE SFC TODAY WILL ALSO KEEP
TEMPERATURES SLIGHT COOLER THAN NORMAL IN THE MID TO UPPER 70S
ALONG WITH INCREASING HUMIDITY.
TONIGHT, OUR UPSTREAM TROUGH OVER THE GREAT LAKES AMPLIFIES AND
DIG INTO THE OHIO VALLEY AS TWO SHORTWAVES PHASE TOGETHER WITH
THE PARENT CYCLONE TAKING ON A NEGATIVE TILT. THIS RESULTS IN
STRENGTHENING UPPER LEVEL DIFFLUENCE OVER THE MID-ATLANTIC AS A
WARM FRONT LIFTS NORTHWARD WITH A WEAK SFC LOW DEVELOPING ALONG
THE BOUNDARY. MEANWHILE, STRENGTHENING SOUTHWEST FLOW ALOFT
WILL ALSO ALLOW MOISTURE TO ADVECT INTO THE NORTHEAST WITH PWATS
RISING OVER 1.50". CHANCE FOR SHOWERS AND EVEN A SLIGHT CHANCE
FOR THUNDERSTORMS INCREASES FROM SOUTHWEST TO NORTHEAST 06 - 12
UTC SUNDAY AS THE FRONT APPROACHES. GUIDANCE CONTINUES TO HINT
THAT THE WEAK SFC LOW AIDS IN THE DEVELOPMENT OF MORE ORGANIZED
AREA OF RAIN/EMBEDDED STORMS. AS MENTIONED IN THE PREVIOUS
DISCUSSION, THE LATEST PROBABILISTIC GUIDANCE FROM THE HREF
CONTINUES TO SHOW POTENTIAL FOR MODERATE TO HEAVY RAIN LATE
TONIGHT INTO SUNDAY MORNING WITH A 50 - 75% CHANCE FOR OVER
0.50" OF RAIN 09 - 15 UTC SUN AND EVEN A 25-50% CHANCE FOR OVER
1" OF RAIN. WPC MAINTAINS A MARGINAL RISK (LEVEL 1 OF 4) FOR
EXCESSIVE RAINFALL THROUGH 12 UTC SUNDAY IN THE MID-HUDSON
VALLEY, EASTERN CATSKILLS AND NW CT LIKELY FOR THIS POTENTIAL.
AFTER THIS INITIAL A.M PERIOD OF RAIN/STORMS, WE SHOULD HAVE A
BRIEF BREAK BEFORE AN OCCLUDED FRONT AND STRONGER HEIGHT
FALLS FROM THE CLOSED PARENT LOW OVER THE EASTERN GREAT LAKES
ARRIVE. THERE REMAIN UNCERTAINTIES REGARDING HOW MUCH
INSTABILITY CAN DEVELOP. WHILE THERE WILL BE PLENTY OF LOW-
LEVEL MOISTURE, MORNING CLOUDS MAY STRUGGLE TO BREAK FOR SUN
DURING THE SMALL WINDOW BEFORE THE OCCLUDED FRONT ARRIVES SUN
P.M. EVEN STILL, MID-LEVEL DRY AIR AND COOLER TEMPERATURES ALOFT
WRAP EASTWARD AS THE PARENT CYCLONE MATURES, HELPING TO STEEPEN
LAPSE RATES WITH FORECAST SOUNDINGS SHOWING "TALL- SKINNY" CAPE
DEVELOPING. GIVEN THE HIGH HUMIDITY, EVEN LIMITED INSOLATION
WILL CONTRIBUTE TO SUFFICIENT INSTABILITY AND HELP GENERATE LOW-
TOPPED CONVECTION. WHILE 0-6KM SHEAR IS RATHER IMPRESSIVE
RANGING 40-50KTS, 0-3KM SHEAR ONLY RANGES 20-30KTS. SHOULD WEAK
INSTABILITY KEEP CONVECTION LOW-TOPPED, STORMS WILL NOT TAP INTO
THE STRONGER DEEP LAYER SHEAR, DECREASING THE SEVERE WEATHER
POTENTIAL. SPC EXPANDED THE MARGINAL RISK (LEVEL 1 OF 5) FOR
ISOLATED SEVERE WEATHER TO NOW COVER MUCH OF EASTERN NY AND
WESTERN NEW ENGLAND GIVEN PERSISTENT FORCING AHEAD OF THE PARENT
CYCLONE; HOWEVER, WEAK INSTABILITY/SHEAR ARE LISTED AS REASONS
WILL SEVERE WEATHER MAY BE LIMITED. MAIN CONCERNS ARE DAMAGING
WINDS FROM ANY SEVERE WEATHER WITH A LINEAR STORM MODE FAVORED
AS SHEAR VECTORS REMAIN PARALLEL TO THE BOUNDARY.
KEY MESSAGE 2...
THE VERTICALLY STACK CLOSED LOW AND ASSOCIATED COLD POOL IN THE
EASTERN GREAT LAKES SLOWLY ADVANCES EASTWARD MONDAY INTO TUESDAY
SUPPORTING SLIGHTLY COOLER THAN NORMAL TEMPERATURES AND
CONTINUED MOIST CYCLONIC FLOW ALOFT. COVERAGE OF SHOWERS AND
EVEN LOW- TOPPED CONVECTION INCREASES MONDAY AFTERNOON,
ESPECIALLY NEAR/NORTH OF I-90, AS ADDITIONAL SHORTWAVES ROTATE
AROUND THE BASE OF THE CLOSED LOW. GIVEN THE COOL POOL ALOFT, IT
LIKELY WILL NOT TAKE MUCH UPSCALE GROWTH BEFORE LIGHTNING
OCCURS WITH EVEN SMALL HAIL POSSIBLE FROM ANY TALLER STORMS. AS
WINDS ALOFT BECOMING WESTERLY, A WEAK LAKE EFFECT SIGNAL LOOKS
TO DEVELOP DOWNSTREAM OF LAKE ONTARIO, SUPPORTING STEADIER
PERIODS OF RAIN DIRECTED INTO THE WESTERN ADIRONDACKS AND MOHAWK
VALLEY MONDAY P.M INTO MONDAY NIGHT. UNSETTLED CONDITIONS
CONTINUE INTO TUESDAY WITH ADDITIONAL DIURNALLY DRIVEN SHOWERS
AGAIN MAINLY NEAR/NORTH OF I-90 BUT SHOWER COVERAGE SHOULD BE
LOWER THAN MONDAY AS THE PARENT CYCLONE SLOWLY EXITS INTO NEW
ENGLAND.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
THROUGH 06Z SUNDAY...VFR CONDITIONS CURRENTLY PREVAIL AT ALL SITES
WITH THE EXCEPTION OF PSF WHERE VISIBILITY AND CEILING HEIGHTS HAVE
LOWERED INTO THE LIFR CATEGORY DUE TO FOG FORMATION. INFRARED
SATELLITE SHOWS HIGH CLOUDS STREAMING INTO THE REGION FROM THE SOUTH
WHICH SHOULD COMPLETELY MITIGATE FOG DEVELOPMENT AT POU AND
POTENTIALLY LIMIT THE DURATION OF UNFAVORABLE FLYING CONDITIONS AT
PSF. HOWEVER, AS THESE CLOUDS WILL TAKE SOME TIME TO SPREAD INTO ALB
AND GFL, IT IS POSSIBLE THAT SOME FOG COULD ALSO FORM AT THESE TWO
SITES. FOG AT ALB WOULD MORE LIKELY BE FAIRLY SHALLOW AND NOT POSE A
WORSENING OF CONDITIONS THAT FORCES A CATEGORY CHANGE OUT OF VFR.
HOWEVER, GFL COULD SEE A VISIBILITY REDUCTION AND POTENTIALLY A
DEVELOPED CEILING INTO THE IFR CATEGORY. TEMPOS WERE ADDED
ACCORDINGLY.
ONCE SUFFICIENT CLOUD COVER MOVES OVER THE TERMINALS AND/OR THE SUN
STARTS TO BREAK THROUGH UPON SUNRISE, ALL SITES WILL SEE CONDITIONS
RETURN, IF THEY HAVEN'T ALREADY, TO THE VFR CATEGORY. FOR THE VAST
MAJORITY OF THE 06Z PERIOD, VFR CONDITIONS WILL REMAIN IN PLACE.
HOWEVER, FORECAST SOUNDINGS AT POU AND PSF INDICATED THE POTENTIAL
FOR INCREASING LOW-LEVEL MOISTURE TO LEAD TO THE DEVELOPMENT OF MVFR
CEILINGS AT TIMES THIS AFTERNOON. TEMPO AND PREVAILING GROUPS WERE
ADDED ACCORDINGLY. WINDS THROUGHOUT THE PERIOD WILL LARGELY PREVAIL
OUT OF THE SOUTHEAST AT SUSTAINED SPEEDS UNDER 10 KT.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: LOW OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
DISCUSSION...24/31
AVIATION...12
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