570
FXUS61 KALY 061456
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1056 AM EDT TUE MAY 6 2025
SYNOPSIS
PERIODS OF RAIN AND SHOWERS, LOCALLY HEAVY AT TIMES,
CONTINUE TODAY INTO TONIGHT WITH BELOW NORMAL DAYTIME HIGHS AND
ABOVE NORMAL OVERNIGHT LOWS. THERE IS A CHANCE OF THUNDERSTORMS THIS
AFTERNOON AND AGAIN ON WEDNESDAY. TEMPERATURES WILL BE CLOSER TO
NORMAL ON WEDNESDAY, BUT TREND BACK BELOW NORMAL FOR THE END OF THE
WEEK WITH ADDITIONAL CHANCES FOR RAINFALL.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- FLOOD WATCH IN EFFECT FOR THE EASTERN CATSKILLS, MID HUDSON
VALLEY, CENTRAL AND SOUTHERN TACONICS, BERKSHIRES AND
LITCHFIELD HILLS THROUGH 8 PM TUESDAY.
- SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TODAY. ANY STORMS
COULD PRODUCE LOCALLY HEAVY RAIN, AND A FEW STORMS COULD BE
SEVERE FOR AREAS FROM THE HUDSON VALLEY WESTWARDS.
DISCUSSION:
UPDATE...AS OF 1056 AM EDT
THE MOST NOTABLE CHANGE WITH THIS
UPDATE WAS TO EXPAND THE FLOOD WATCH TO INCLUDE SCHOHARIE AND
WESTERN ALBANY COUNTIES. GIVEN THE LATEST GUIDANCE, THE HEAVIEST
SHOWERS AND DOWNPOURS WITHIN THUNDERSTORMS ARE MORE PROBABLE TO
THE WEST OF THE HUDSON RIVER VALLEY WITH UPSLOPE ENHANCEMENT IN
THE EASTERN CATSKILLS AND HELDERBERGS PROMOTING GREATER
RAINFALL ACCUMULATIONS. WITH THESE AREAS ALREADY HAVING 1.5 TO 3
INCHES OVER THE LAST THREE DAYS, SOILS ARE CERTAINLY SATURATED
AND ADDITIONAL ACCUMULATIONS OF 0.5" TO LOCALIZED 1" COULD CAUSE
BASINS TO BECOME FULL, LEADING TO POTENTIAL PONDING OF WATER
AND AN ISOLATED FLASH FLOOD. OTHERWISE, ONLY MINOR ADJUSTMENTS
WERE NEEDED TO ENSURE CONSISTENCY WITH LATEST OBS. SEE THE
PREVIOUS DISCUSSION BELOW FOR ADDITIONAL DETAILS.
PREVIOUS
CURRENT GOES 16 WV IMAGERY SHOWS OUR UPPER LOW NOW
LOCATED OVER OHIO, AND IT IS NEARLY VERTICALLY STACKED WITH A
COLLOCATED SURFACE LOW. WITH SURFACE HIGH PRESSURE CENTERED NEAR
NOVA SCOTIA, THIS IS SETTING UP A LONG FETCH OF SOUTHERLY FLOW
INTO THE NORTHEAST. THIS SOUTHERLY FLOW IS ADVECTING A DEEP
PLUME OF MOISTURE-RICH AIR INTO THE REGION AS SEEN ON CIRA ALPW
SATELLITE IMAGERY. UNSURPRISINGLY, THIS HAS RESULTED IN PERIODS
OF WIDESPREAD RAIN AND SHOWERS OVERNIGHT, WHICH ARE CONTINUING
TO TAPER OFF ACROSS THE REGION AT THIS TIME.
TODAY, THE CUTOFF UPPER LOW SLIDES EASTWARDS OVER PA, EVENTUALLY
TRACKING OVER THE SOUTHERN TIER OF NY TONIGHT. THIS SETUP WILL
KEEP THE S/SE LLJ FOCUSED OVER EASTER NY AND WESTERN NEW
ENGLAND. WHILE THE CORE OF THE LLJ AND THE HIGHEST PWATS SLIDE
OFF INTO EASTERN NEW ENGLAND TODAY AS THE UPPER LOW PROGRESSES
EASTWARDS, OUR PWATS STILL REMAIN WELL ABOVE NORMAL AT 1 - 1.25"
FOR MOST OF TODAY. WE WILL LIKELY SEE A LULL IN SHOWER ACTIVITY
FOR A FEW HOURS THIS MORNING AS THIS CURRENT BATCH OF SHOWERS
MOVES OFF TO THE NORTH/EAST, BUT ADDITIONAL SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON. FORCING
FOR ASCENT LOOKS IMPRESSIVE TODAY, WITH A SHORTWAVE LOBE
ROTATING AROUND THE PERIPHERY OF THE UPPER LOW, THE APPROACHING
RIGHT ENTRANCE OF THE UPPER JET, AND THE OCCLUDED FRONT
ASSOCIATED WITH THE SURFACE LOW ALL PASSING OVER OUR REGION
THIS AFTERNOON. ADDITIONALLY, THERE WILL BE MORE INSTABILITY
COMPARED TO YESTERDAY, SO RAINFALL RATES TODAY WILL LIKELY BE
HIGHER THAN YESTERDAY, UP TO AROUND OR POSSIBLY EVEN IN EXCESS
OF 1" PER HOUR WITH CONVECTION.
THEREFORE, THE PRIMARY THREAT TODAY WILL BE FOR LOCALLY HEAVY
RAIN LEADING TO SOME PONDING OF WATER IN URBAN/POOR DRAINAGE
AREAS, AND ISOLATED FLASH FLOODING. SOILS ARE ALREADY SATURATED
FROM ALL THE RAIN WE HAVE RECEIVED OVER THE PREVIOUS DAYS.
UNIDIRECTIONAL FLOW PROFILES INDICATE THAT THERE COULD BE SOME
TRAINING OF CONVECTION TODAY, ALTHOUGH STORM MOTIONS SHOULD BE
ON THE FASTER SIDE OUTSIDE OF ANY BACKBUILDING STORMS. THE
LOCATION OF THE UPPER LOW AND MOISTURE PLUME FIT THE CONCEPTUAL
MODEL FOR HEAVY RAIN DEVELOPED AS PART OF LOCAL CSTAR RESEARCH,
AND WPC HAS MAINTAINED THEIR MARGINAL RISK ERO FOR TODAY ACROSS
THE REGION. THE TIMING FOR ANY HEAVY RAIN LOOKS TO BE PRIMARILY
THIS AFTERNOON INTO EARLY TONIGHT. MINOR FLOODING ON A FEW MAIN
STEM RIVERS IS ALSO POSSIBLE DUE TO PERSISTENT RAINS OVER THE
LAST FEW DAYS. PLEASE SEE THE HYDRO SECTION FOR MORE DETAILS.
A SECONDARY THREAT THIS AFTERNOON/EVENING IS THAT FOR A FEW
SEVERE STORMS. SPC HAS EXPANDED THE MARGINAL RISK OUTLOOK
FURTHER EAST INTO THE HUDSON VALLEY, LIKELY DUE IN PART TO
SLIGHTLY QUICKER EXPECTED FORWARD PROGRESS OF THE UPPER LOW
COMPARED TO YESTERDAY. FALLING HEIGHTS ALOFT LEADING TO
STEEPENING MID-LEVEL LAPSE RATES WILL BE ASSOCIATED WITH UP TO
AROUND 1000 J/KG OF SBCAPE IN THE WESTERN MOHAWK VALLEY, AND
AROUND 250-750 J/KG FOR MOST OF THE REST OF THE REGION WEST OF
THE HUDSON VALLEY. THIS WILL OVERLAP WITH DEEP-LAYER BULK SHEAR
OF 30-40 KT. HODOGRAPHS ARE FAIRLY STRAIGHT, SO WE WOULD NOT BE
SURPRISED TO SEE SOME LOOSELY ORGANIZED CLUSTERS OF STORMS OR
BROKEN LINE SEGMENTS THIS AFTERNOON/EVENING, ESPECIALLY FOR THE
WESTERN HALF OF THE REGION. PRIMARY HAZARD WITH ANY STRONGER
STORMS WILL BE DAMAGING WINDS, ALTHOUGH SOME MARGINALLY SEVERE
HAIL CAN'T BE RULED OUT DUE TO LOW WBZ HEIGHTS BELOW 10 KFT.
CONVECTION SHOULD WEAKEN EARLY TONIGHT WITH THE LOSS OF DAYTIME
HEATING, SO BOTH THE SEVERE AND HEAVY RAINFALL THREATS WILL ALSO
DECREASE AS WE HEAD INTO TONIGHT. THERE WILL LIKELY STILL BE
SOME SHOWER ACTIVITY CONTINUING INTO TONIGHT, HOWEVER. TONIGHT
ONCE AGAIN REMAINS ON THE MILD SIDE WITH LOWS IN THE 40S TO 50S
LIKE WE HAVE HAD THE LAST FEW NIGHTS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/
WEDNESDAY...THE CUTOFF UPPER LOW MOVES OVERHEAD, WHILE THE
AFOREMENTIONED SURFACE LOW TRACKS OFF TO OUR NORTH/NORTHEAST.
THE UPPER LOW NOW LOOKS TO TRACK EASTWARDS SLIGHTLY QUICKER
THAN PREVIOUSLY EXPECTED, SO THE CORE OF THE COLD POOL ALOFT MAY
BE STARTING TO DEPART TO OUR EAST BY THE TIME WE GET INTO PEAK
AFTERNOON HEATING. WHILE WE WILL STILL LIKELY SEE SOME POP-UP
SHOWERS AND A FEW THUNDERSTORMS, ESPECIALLY NORTH AND EAST OF
THE CAPITAL DISTRICT, INSTABILITY OVERALL LOOKS LESS IMPRESSIVE
COMPARED TO YESTERDAY'S FORECAST. WHILE A FEW INSTANCES OF SMALL
HAIL WILL BE POSSIBLE DUE TO THE PROXIMITY TO THE COLD POOL
ALOFT, SEVERE WEATHER IS NOT EXPECTED (SHEAR WILL BE WEAK UNDER
THE UPPER LOW). ADDITIONALLY, HEAVY RAIN SHOULD NOT POSE A
THREAT EITHER, AS THE BEST MOISTURE WILL BE WELL TO OUR EAST.
SHOWER ACTIVITY SHOULD DIMINISH HEADING INTO THE EVENING WITH
RIDING HEIGHTS AND SUBSIDENCE ALOFT BEHIND THE DEPARTING UPPER
LOW. HIGHS WEDNESDAY WILL BE A FEW DEGREES WARMER, MAINLY IN THE
MID TO UPPER 60S OUTSIDE OF THE MOUNTAINS.
WEDNESDAY NIGHT AND THURSDAY...THE UPPER LOW MOVES OFF INTO
NORTHEASTERN NEW ENGLAND, AS ANOTHER UPPER TROUGH DIGS INTO THE
GREAT LAKES REGION. THIS WILL HELP TO PUSH A COLD FRONT THROUGH
OUR REGION WEDNESDAY NIGHT, AND THE COLD FRONT SETTLES NEAR THE
I-84 CORRIDOR THURSDAY AFTERNOON. WHILE A FEW LIGHT SHOWERS WILL
BE POSSIBLE WITH THE COLD FRONTAL PASSAGE, MOST OF WEDNESDAY
NIGHT LOOKS DRY. THERE COULD BE A FEW MORE SHOWERS FOR SOUTHERN
AREAS THURSDAY, ESPECIALLY IN THE AFTERNOON, IF THE UPPER TROUGH
PHASES WITH AN UPPER SHORTWAVE TRACKING INTO THE OHIO VALLEY
(SEE LONG TERM SECTION BELOW FOR MORE DETAILS). WEDNESDAY NIGHT
LOWS WILL BE A FEW DEGREES COOLER THAN PREVIOUS NIGHTS. HIGHS
THURSDAY WILL RANGE FROM THE UPPER 50S IN THE ADKS TO LOW 70S
AHEAD OF THE FRONT FOR AREAS NEAR THE I-84 CORRIDOR.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
KEY MESSAGE:
- HIGH CHANCE TO LIKELY PROBABILITIES (50-70%) FOR A
WIDESPREAD RAINFALL THU NIGHT THROUGH FRI AND BELOW NORMAL TEMPS
LATE IN THE WEEK INTO THE UPCOMING WEEKEND.
DISCUSSION:
THE MEDIUM RANGE DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUES TO
SHOW GOOD CONSISTENCY FOR CLOUDS TO INCREASE AHEAD OF POSITIVELY
TILTED MID AND UPPER LEVEL TROUGH THAT APPROACHES FROM THE GREAT
LAKES REGION AND SOUTHEAST CANADA THU NIGHT INTO FRI. LOW PRESSURE
FORMS OVER THE MID ATLANTIC STATES AND PERIODS OF RAIN DEVELOP AHEAD
OF THE WAVE AND WARM FRONT FRI MORNING, AND THEN MAY EXTEND INTO FRI
NIGHT/SAT MORNING. THE MID AND UPPER LEVEL LOW MAY CUT-OFF OVER NY
AND PA AND THEN LIFT THROUGH QUICKLY BY THE BEGINNING OF THE
WEEKEND. NBM 24-HR PROBABILITIES BY 00Z/8 PM SAT FOR >0.25" RAIN
ACROSS THE FORECAST AREA ARE IN THE 50-75% RANGE. NBM PROBS FOR
>0.50" OF RAIN HAVE RISEN TO 30-50% FOR THE SAME TIME FRAME. THE
PERIODS OF RAIN COULD BE MODERATE TO HEAVY AND WITH SOGGY AND
SATURATED CONDITIONS AHEAD OF THIS SYSTEM, THEN SOME HYDRO ISSUES
(POSSIBLY FLOODING) MAY ARISE. RIGHT NOW, LOCATIONS SOUTH AND EAST
OF THE CAPITAL REGION MAY HAVE THE GREATEST THREAT FOR RAIN TOTALS
APPROACHING AN INCH OR MORE. LOWS THU NIGHT WILL RANGE FROM
MID/UPPER 30S OVER THE SOUTHERN DACKS AND SOUTHERN GREENS TO LOWER
OR MID 40S OVER THE REST OF THE FORECAST AREA. IN THE RAIN COOLED
AIR MASS, BELOW NORMAL TEMPS ARE EXPECTED FRI IN THE UPPER 40S TO
MID AND UPPER 50S. AS THE CLOSED LOW PULLS AWAY FRI NIGHT LOWS MAY
FALL BACK INTO THE MID 30S TO MID 40S WITH SCATTERED SHOWERS ENDING.
SOME ISOLATED TO WIDELY SCATTERED SHOWERS MAY LINGER DUE TO THE
CYCLONIC VORTICITY ADVECTION ASSOCIATED WITH THE CLOSED/CUT-OFF LOW
TO OPEN THE WEEKEND. THE OCCLUDED CYCLONE MOVES TOWARDS THE GULF OF
MAINE IN THE AFTERNOON. TEMPS MODERATE CLOSER TO NORMAL WITH MID
60S TO NEAR 70F IN THE VALLEYS AND UPPER 50S TO MID 60S OVER THE
HIGHER TERRAIN. DRIER WEATHER RETURNS SAT NIGHT WITH CLEARING SKIES
AND COOL TEMPS IN THE UPPER 30S TO MID 40S. HIGH PRESSURE BUILDS IN
WITH FAIR, SEASONABLE AND DRY WEATHER FOR MOTHERS DAY WITH MOSTLY
SUNNY SKIES AND BREEZY CONDITIONS. THE SFC ANTICYCLONE SHIFTS
OFFSHORE EARLY NEXT WEEK WITH A RETURN FLOW OF MILDER AIR, AS TEMPS
RISE BACK ABOVE NORMAL TO OPEN THE WEEK.
AVIATION /15Z TUESDAY THROUGH SATURDAY/
THROUGH 12Z/WED...SOME LIGHT RAIN SHOWERS CONTINUE NORTH AND
EAST OF KALB TOWARDS KGFL/KPSF THIS MORNING WITH WIDESPREAD MVFR
CONDITIONS IN TERMS OF CIGS, WHEREAS THE SHOWERS HAVE DIMINISHED
NEAR KPOU WITH IFR CIGS. WIDESPREAD MVFR CONDITIONS CONTINUE
UNTIL 16Z/TUE WITH INTERMITTENT IFR CIGS AT KPOU AND POSSIBLY
KPSF. SHOWERS BUILD NORTHWARD BETWEEN 16Z-19Z/TUE. PROB30 GROUPS
FOR TSRA GROUPS WERE USED BETWEEN 16Z-20Z/TUE AT KPOU FIRST,
AND THEN 18Z-23Z/TUE EXPANDING NORTHWARD FOR KALB/KPSF/KGFL
WITH ANOTHER SURGE OF ATLANTIC MOISTURE WITH SHORT-WAVE ENERGY
ROTATING AROUND THE CLOSED LOW. SOME REDUCTIONS FROM VFR/MVFR
LEVELS WITH IFR LEVELS MAY OCCUR WITH ANY EMBEDDED
THUNDERSTORMS. THE LIGHT SHOWERS CONTINUE INTO THE EARLY EVENING
WITH WIDESPREAD MVFR/LOW VFR CONDITIONS. SOME DRIZZLE MAY
LINGER FROM KALB NORTHWARD TO KGFL AFTER 06Z/WED. SOME
IMPROVEMENT TO HIGHER MVFR/VFR CIGS MAY OCCUR FOR KPOU/KPSF
AFTER 06Z/WED, BUT CONFIDENCE REMAINS LOW.
THE WINDS BECOME EAST TO SOUTHEAST AT 5-10 KT IN THE LATE
MORNING INTO THE AFTERNOON. THE WINDS WILL BECOME SOUTHERLY AT
LESS THAN 10 KT OR LESS TONIGHT. LLWS CONTINUES PRIOR 15Z/TUE
AT KALB/KPSF/KGFL, AS A LOW- LEVEL JET BRINGS 2 KFT WINDS
BETWEEN 35-40 KT WITH SFC WINDS GENERALLY UNDER 10 KT.
OUTLOOK...
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: LOW OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
SATURDAY: LOW OPERATIONAL IMPACT. BREEZY. SLIGHT CHANCE OF SHRA.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
HYDROLOGY
FLOOD WATCH IN EFFECT FOR THE EASTERN CATSKILLS, MID HUDSON
VALLEY, CENTRAL AND SOUTHERN TACONICS, BERKSHIRES AND LITCHFIELD
HILLS THROUGH 8 PM THIS EVENING.
PERIODS OF RAIN CONTINUE THROUGH TODAY, WITH LOCALLY HEAVY RAIN
EXPECTED, ESPECIALLY THIS AFTERNOON AND EARLY EVENING. WHERE
HEAVY RAIN CAN REPEATEDLY MOVE OVER THE SAME AREAS, SOME
FLOODING OF URBAN, LOW-LYING AND POOR DRAINAGE AREAS IS
EXPECTED. EVEN ISOLATED FLASH FLOODING MAY OCCUR WHERE THE
HEAVIEST RAIN FALLS, ESPECIALLY IF IT OCCURS OVER THE MORE
SUSCEPTIBLE URBAN AREAS. WPC CONTINUES TO HAVE A MARGINAL RISK
FOR EXCESSIVE RAINFALL ACROSS THE REGION TODAY.
ADDITIONAL RAINFALL AMOUNTS TONIGHT THROUGH TONIGHT RANGING
BETWEEN 1 AND 3 INCHES (WITH THE HIGHEST AMOUNTS IN THE EASTERN
CATSKILLS DUE TO UPSLOPE ENHANCEMENT), COMBINED WITH ALREADY
SATURATED GROUND HAS INCREASED THE RISK OF FLASH FLOODING IN THE
WATCH AREA.
THE HOUSATONIC AT STEVENSON DAM AND THE STILL RIVER AT
BROOKFIELD HAVE HIT MINOR FLOOD STAGE DUE TO THE RAIN OVERNIGHT.
LATEST ENSEMBLE RIVER FORECASTS INDICATE LOW TO MEDIUM
PROBABILITIES (~10-30%) FOR SOME ADDITIONAL POINTS TO REACH
MINOR FLOOD STAGE, MOST NOTABLY ALONG THE HOUSATONIC RIVER,
ESOPUS CREEK, WEST CANADA CREEK, HOOSIC RIVER, SCHOHARIE CREEK,
AND ON THE WALLOOMSAC.
ALY WATCHES/WARNINGS/ADVISORIES
CT...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ047-051-058>061-
063>066.
MA...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025.
VT...NONE.
SYNOPSIS...MAIN/JPV
NEAR TERM...GANT/MAIN
SHORT TERM...MAIN
LONG TERM...WASULA
AVIATION...WASULA
HYDROLOGY...MAIN/JPV
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