297
FXUS61 KALY 042040
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
440 PM EDT SUN MAY 4 2025
SYNOPSIS
PERIODS OF RAIN AND SEASONABLY COOL TEMPERATURES PERSIST
THROUGH TUESDAY. AREAS OF MODERATE TO HEAVY RAIN ARE LIKELY AT TIMES
WHICH CAN RESULT IN LOCALIZED POOR DRAINAGE AND URBANIZED FLOODING
AND RIVER RISES. SHOWERS TURN LESS NUMEROUS BY THE END OF THE
WEEK BUT SEASONABLY COOL TEMPERATURES CONTINUE.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
KEY MESSAGE:
- PERIODS OF MODERATE TO LOCALLY HEAVY RAIN EXPECTED LATE THIS
AFTERNOON THROUGH TONIGHT. TOTAL RAINFALL AMOUNTS RANGE FROM 1
TO 2.5 INCHES WITH 30 TO 60% CHANCE FOR AMOUNTS TO EXCEED 2
INCHES IN THE EASTERN CATSKILLS, TACONICS INTO BERKSHIRE
COUNTY AND PARTS OF SOUTHERN VT WHICH MAY RESULT IN LOCALIZED
POOR DRAINAGE AND URBANIZED FLOODING.
DISCUSSION:
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS OUR CUT-OFF LOW
SPINNING OVER THE TN/OHIO VALLEY WITH SOUTHERLY WINDS AHEAD OF
IT ALONG THE EAST COAST ADVECTING A NOTABLE MOISTURE PLUME OUT
OF THE GULF AND WESTERN ATLANTIC NORTHWARD. WITH AN AREA OF HIGH
PRESSURE SLIDING EASTWARD ACROSS QUEBEC TODAY, THE STRONGEST
UPPER LEVEL DIFFLUENCE IS POSITIONED FROM THE MID-ATLANTIC INTO
NY/WESTERN NEW ENGLAND WITH THE AXIS OF DILATATION ORIENTED
ALONG THE INTERNATIONAL BORDER AND IS CLEARLY SEEN ON WATER
VAPOR AND IR IMAGERY. AS THE CUT-OFF LOW CONTINUES TO SLOWLY
ADVANCE EASTWARD INTO TONIGHT, THE CONVEYOR BELT OF DEEP
SOUTHERLY WINDS (25-30KTS) WILL REMAIN DIRECTED INTO THE
NORTHEAST WITH ITS MOISTURE PLUME CHARACTERIZED BY PWAT VALUES 1
- 1.5 INCHES. AS A RESULT, THE MODERATE TO HIGH COVERAGE OF
AREAS OF SHOWERS AND EMBEDDED POCKETS OF MODERATE/STEADY RAIN
WILL REMAIN OVER OUR AREA. THEREFORE, POPS REMAIN HIGH (75 -
90%) TONIGHT. FAR NORTHERN HERKIMER/HAMILTON COUNTY IS THE
EXCEPTION WHERE POPS SHOULD TREND DOWNWARDS THIS
AFTERNOON/TONIGHT AS A MID- LEVEL BOUNDARY SHIFTS SOUTHWARD.
TOTAL RAINFALL AMOUNTS 18 UTC TODAY THROUGH 12 UTC MONDAY
EXPECTED TO RANGE 0.5 TO 1.50 INCHES. PROBABILITIES GUIDANCE
FROM THE HREF EVEN SHOWS GREATER THAN 75% CHANCE FOR 3-HOURLY
RAINFALL AMOUNTS TO EXCEED 0.50" AT TIMES LATE THIS AFTERNOON
INTO TONIGHT AS POCKETS OF EMBEDDED THUNDERSTORMS TRACK INTO THE
AREA AND THE AFOREMENTIONED MID-LEVEL BOUNDARY OVER THE
SOUTHERN ADIRONDACKS SHIFTS TOWARDS THE I-90 CORRIDOR AND
MOISTURE/FORCING BECOMES FOCUSED ALONG IT, ENHANCING RAINFALL
AMOUNTS. SOUTHEAST WINDS IN THE LOW-LEVELS CAN ALSO LOCALLY
ENHANCE RAINFALL RATES/AMOUNTS IN THE EASTERN CATSKILLS DUE TO
UPSLOPING. WPC MAINTAINS A WIDESPREAD MARGINAL RISK IN ITS
EXCESSIVE RAINFALL OUTLOOK ACROSS MOST OF OUR AREA THROUGH 12
UTC MONDAY FOR FLASH FLOODING.
TEMPERATURES TODAY WILL REMAIN COOLER THAN NORMAL BY EARLY MAY
STANDARDS AS REMAIN NORTH OF THE STALLED SFC BOUNDARY OVER
NJ INTO EASTERN NEW ENGLAND WITH NORTHERLY WINDS MAINTAINING
COOL AIR WEDGE SEEN ON THE 12 UTC ALY SOUNDING. HIGH
TEMPERATURES TODAY LIKELY STRUGGLE TO RISE OUT OF THE 50S AND
LOW 60S (MID-60 MID-HUDSON VALLEY AND NW CT). LITTLE DIURNAL
CHANGE EXPECTED TONIGHT DUE TO RAIN AND CLOUDS WITH OVERNIGHT
LOWS IN THE UPPER 40S AND 50S.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
KEY MESSAGE:
- PERIODS OF RAIN CONTINUE THROUGH TUESDAY, SOME OF WHICH COULD
BE HEAVY AT TIMES, ESPECIALLY MONDAY NIGHT INTO TUESDAY.
THERE IS A 10 TO 25% CHANCE FOR A FEW RIVER POINTS TO REACH
MINOR FLOOD STAGE MAINLY ALONG THE HOUSATONIC, HOOSIC AND
WALLOOMSAC.
DISCUSSION:
MONDAY THROUGH TUESDAY WILL REMAIN QUITE WET AS OUR CUT-OFF LOW
CONTINUES ITS SLOW APPROACH FROM THE OHIO VALLEY WITH AN
INCREASINGLY STRONG SOUTHERLY JET MAINTAINING A DEEP MOISTURE
FETCH OUT OF THE GULF AND WESTERN ATLANTIC INTO THE NORTHEAST.
OVERALL INSTABILITY VALUES TOMORROW WILL REMAIN LOW GIVEN
WIDESPREAD CLOUD COVERAGE AND WITHOUT INSTABILITY, RAINFALL
RATES SHOULD BE KEPT IN CHECK DESPITE PERIODS OF RAIN THROUGH
THE DAY. THERE SHOULD BE SOME BREAKS OF DRY TIME, MAINLY NORTH
OF I-90, AS THE BOUNDARY CONTINUES TO SHIFT SOUTHWARD DUE TO
HIGH PRESSURE BUILDING FURTHER INTO THE CANADIAN MARITIMES AND
NOSING INTO NORTHERN NEW ENGLAND. SOUTHEASTERLY WINDS UPSLOPE
THE TERRAIN IN THE EASTERN CATSKILLS WILL LIKELY KEEP RAINFALL
RATES MODERATE THROUGH THE DAY WITH RAINFALL RATES FROM THE
HREF SUGGESTING 50-60% CHANCE FOR 3-HRLY AMOUNTS TO EXCEED
0.50" MOST OF THE DAYTIME. OTHERWISE, NORTHERLY WINDS BEHIND THE
BOUNDARY WILL KEEP TEMPERATURES COOL ONCE AGAIN IN THE 50S TO
LOW 60S, COOLEST IN WESTERN NEW ENGLAND.
WITH THE CUT-OFF LOW INCHING INTO WESTERN PA MONDAY NIGHT AND
OUR 1035HPA HIGH STEADFAST IN THE CANADIAN MARITIME, THE
SOUTHERLY JET AND CONVEYOR BELT OF MOISTURE LIKELY STRENGTHENS
WITH WINDS REACHING 35 - 45KTS. AS THE AXIS OF THE HIGHEST
PWATS BECOMES DIRECTED INTO THE REGION (VALUES 2 - 2.5 STD DEV
ABOVE NORMAL PER THE NAEFS) AND INCREASING HEIGHT FALLS AHEAD
OF THE APPROACHING LOW SUPPORT ENHANCED FORCING FOR ASCENT,
PERIODS OF MODERATE TO HEAVY RAIN BECOME MORE WIDESPREAD ACROSS
EASTERN NY AND WESTERN NEW ENGLAND. AGAIN, EASTERN CATSKILLS
LIKELY THE BULLS-EYE FOR THE HIGHEST RAIN AMOUNTS GIVEN THE
FAVORABLE SOUTHEAST WINDS ALOFT WITH PROBABILITIES FOR 3-HRLY
RAINFALL AMOUNTS EXCEEDING 0.5" CONTINUING TO BE GREATER THAN
75% MOST OF THE NIGHT. ADDITIONAL RAINFALL MONDAY NIGHT RANGES
FROM 0.25 - 1" ACROSS THE REGION WITH UP TO 0.75 - 1.50" IN THE
EASTERN CATSKILLS WHICH CAN RESULT IN LOCALIZED FLOODING AND
RIVER RISES CONSIDERING RAIN THAT HAS ALREADY FALLEN.
THE BEST OVERLAP OF MOISTURE FETCH AND FORCING OCCURS TUESDAY
INTO TUESDAY AFTERNOON WITH EVEN SOME WEAK INSTABILITY
DEVELOPING AS COOLER AIR ALOFT FROM THE APPROACHING CUT-OFF LOW
STARTS TO SHIFT OVERHEAD. THE MOISTURE CONVEYOR BELT CONTINUES
TO BE POSITIONED INTO THE NORTHEAST WITH THE PWAT PLUME STILL
UNSEASONABLY HIGH BETWEEN 1.25 - 1.50"; HOWEVER, AS THE JET
STARTS TO GRADUALLY SHIFT EASTWARD THROUGH THE DAY, THE HIGHEST
PWAT VALUES ALSO SHIFT TOWARDS NEW ENGLAND. STILL UNCERTAINTY
ON THE EXACT TIMING OF WHEN THE JET SHIFTS EASTWARD AND WITH
STILL A MOISTURE RICH ENVIRONMENT IN PLACE COMBINED WITH
STRONGER FORCING FOR ASCENT, PERIODS OF MODERATE TO HEAVY RAIN
REMAIN IN THE FORECAST. TUESDAY AFTERNOON COULD SEE HEAVIEST
RAINFALL RATES AS MID-LEVEL LAPSE RATES STEEPEN AND THE HIGH DEW
POINTS SUPPORT SUFFICIENT INSTABILITY TO SUPPORT A CHANCE FOR
FOR EMBEDDED THUNDERSTORMS. ANY THUNDERSTORM CAN CERTAINLY
PRODUCE HEAVY DOWNPOURS AND GIVEN THE RECENT STRETCH OF WET
WEATHER, THE GROUND WILL LIKELY BE SATURATED AND MORE VULNERABLE
FOR POOR DRAINAGE AND URBANIZED FLOODING SHOULD HEAVIER RAIN
OCCUR. ALSO, RIVER RISES WILL ALSO NEED TO BE MONITORED.
SEE HYDRO DISCUSSION FOR MORE DETAILS ON TOTAL RAINFALL AMOUNTS
AND POTENTIAL IMPACTS.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
KEY MESSAGE:
- MORE WET WEATHER POSSIBLE LATE THIS WEEK INTO THIS WEEKEND
AND GIVEN THE RECENT STRETCH OF WET WEATHER, AREAS HARDEST
HIT WITH RAINFALL WILL BE MORE VULNERABLE TO LOCALIZED
FLOODING.
DISCUSSION:
OUR CUT-OFF LOW FINALLY MOVES OVERHEAD ON WEDNESDAY AND WITH THE
COOL POOL ALOFT IN PLACE SUPPORTING STEEPER LAPSE RATES AND
STILL SOME ELEVATED DEW POINTS, DIURNALLY DRIVEN SHOWERS AND
SCATTERED THUNDERSTORMS ARE LIKELY AS INSTABILITY SHOULD
INCREASE A BIT, ESPECIALLY DURING THE AFTERNOON HOURS. THE COOL
POOL ALOFT COULD SUPPORT SOME SMALL HAIL SHOULD UPDRAFT GROW
SUFFICIENTLY TALL. THE INCOMING TROUGH AXIS COULD ALSO HELP
FOCUS AND ORGANIZE SHOWERS AND THUNDERSTORMS DURING THE
AFTERNOON HOURS SO WE MAINTAINED LIKELY POPS. AGAIN, GIVEN
RECENT PERIOD OF WET WEATHER, FLOOD FLASH GUIDANCE VALUES WILL
LIKELY BE LOWER AND AREAS COULD BE MORE SUSCEPTIBLE TO
LOCALIZED FLOODING EVEN WITH RELATIVELY LOWER RAIN AMOUNTS.
OTHERWISE, TEMPERATURES SHOULD START TO TREND MILDER AND BECOME
MORE SEASONABLE FOR EARLY MAY.
IT IS HARD TO BELIEVE BUT CHANCES FOR RAIN CONTINUE EVEN FOR THE
SECOND HALF OF THE WEEK. A POTENT COLD FRONT PUSHES THROUGH THE
NORTHEAST WED NIGHT INTO THURSDAY AND WITH YET ANOTHER STRONG
UPPER LEVEL TROUGH AMPLIFYING AS IT SHIFTS INTO THE NORTHEAST,
WE COULD BE DEALING WITH ANOTHER CUT-OFF LOW. NEEDLESS TO SAY,
AREAS WILL LIKELY BE QUITE WET AT THIS POINT AND EVEN MORE
VULNERABLE TO FLOODING, DEPENDING ON WHERE ADDITIONAL RAIN
SETS-UP. STILL SOME UNCERTAINTY ON THE EXACT TRACK OF A
POTENTIAL SECOND CUT-OFF LOW BUT THE GENERAL CONSENSUS IS FOR
IT TO DEVELOP ALONG THE COLD FRONT WHICH LOOKS TO STALL MAINLY
TO OUR SOUTH SOMEWHERE ACROSS THE MID-ATLANTIC INTO NEW ENGLAND.
IT'S NORTHERN FRINGE COULD GRAZE PART OF REGION WHICH AT THIS
TIME POINT WILL LIKELY BE PLENTY SATURATED. STILL PLENTY OF TIME
TO IRON OUT THE DETAILS BUT NOTE THAT ADDITIONAL WET WEATHER IS
POSSIBLE FOR THE END OF THE WEEK INTO THE WEEKEND WHICH COULD
RAISE CONCERNS FOR ADDITIONAL LOCALIZED FLOODING.
AVIATION /19Z SUNDAY THROUGH FRIDAY/
LONG DURATION MVFR/IFR RESTRICTIONS EXPECTED AT ALL TERMINALS AS
RAIN SHOWERS CONTINUE TO DEVELOP THIS AFTERNOON ALONG WITH LOW
CEILINGS AND VISIBILITIES. WIDESPREAD RAIN/SHOWERS SHOULD AREAWIDE
THROUGH 20Z THIS AFTERNOON. IT MAY TAKE A FEW HOURS UNTIL EARLY
THIS EVENING FOR CIGS/VSBYS TO TREND DOWN TO IFR AT GFL, BUT
ONCE THE RAIN BEGINS EXPECT MAINLY IFR CIGS AND MVFR TRENDING TO
IFR VSBYS. TOWARDS SUNSET, VSBYS AND CIGS CONTINUE TO
DETERIORATE TO IFR, WITH SOME POCKETS OF LIFR ESPECIALLY AT PSF.
IFR OR LOWER CONDITIONS AND SHOWERS, OCCASIONALLY MODERATE TO
EVEN HEAVY AT TIMES, CONTINUE OVERNIGHT, BEFORE BECOMING LESS
STEADY AFTER DAYBREAK. THERE COULD BE SOME MODEST IMPROVEMENT
AT POU/PSF WITH EASTERLY WINDS AND DOWNSLOPING OCCURRING AFTER
06-08Z TONIGHT, HOWEVER IFR/MVFR SHOULD STILL CONTINUE AT ALL
SITES THROUGH 18Z MONDAY.
OUTLOOK...
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE SHRA.
TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
WEDNESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
HYDROLOGY
PERIODS OF RAIN ARE EXPECTED TODAY THROUGH TUESDAY, WITH SOME
LOCALLY HEAVY RAIN POSSIBLE, ESPECIALLY MONDAY NIGHT THROUGH
TUESDAY. WHERE HEAVY RAIN CAN REPEATEDLY IMPACT OR TRAIN OVER A
GIVEN AREA CAN LEAD TO POOR DRAINAGE AND URBANIZE FLOODING.
EVEN ISOLATED FLASH FLOODING IS POSSIBLE WHERE THE HEAVIEST RAIN
FALLS. THE WEATHER PREDICTION CENTER MAINTAINS ITS MARGINAL
RISK IN ITS DAY 1-3 EXCESSIVE RAINFALL OUTLOOK OF AT LEAST PARTS
OF EASTERN NY AND WESTERN NEW ENGLAND.
DESPITE CUMULATIVE RAINFALL AMOUNTS TODAY THROUGH TUESDAY NIGHT
RANGING BETWEEN 1.5 AND 3.5 INCHES (UP TO 3-4.5 INCHES IN THE
EASTERN CATSKILLS DUE TO UPSLOPE ENHANCEMENT), THE LATEST
ENSEMBLE RIVER FORECASTS INDICATE ONLY LOW PROBABILITIES
(~10-30%) FOR SOME POINTS TO REACH MINOR FLOOD STAGE, MOST
NOTABLY ALONG THE HOUSATONIC RIVER, WEST CANADA CREEK, HOOSIC
AND WALLOOMSAC. DRY ANTECEDENT CONDITIONS, SIGNIFICANT UPTAKE
OF GREENING VEGETATION AND THE LONG DURATION OF THIS RAIN EVENT WILL
LIKELY OFFSET WIDESPREAD FLOODING CONCERNS. WE COLLABORATED
WITH WPC AND NEIGHBORING WFOS TO HOLD OFF ON A FLOOD WATCH GIVEN
THIS THINKING AND ALSO HELD OFF ON A SLIGHT RISK UPGRADE IN THE
ERO. HOWEVER, SHOULD GREATER RAINFALL AMOUNTS (MORE WIDESPREAD
AMOUNTS IN EXCESS OF 3-4 INCHES) OCCUR, PROBABILITIES OF RIVER
FLOODING WOULD INCREASE AND WILL NEED TO RE-EVALUATE IF A FLOOD
WATCH IS NEEDED. TRENDS WILL BE WATCHED CLOSELY OVER THE NEXT
24-36 HOURS.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...KL/SPECIALE
NEAR TERM...SPECIALE
SHORT TERM...SPECIALE
LONG TERM...SPECIALE
AVIATION...GITRO
HYDROLOGY...KL/JPV/SPECIALE
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