552
FXUS61 KALY 041728
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
128 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 /THROUGH TONIGHT/
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 CURRENTLY POSITIONED OVER THE MID-
ATLANTIC INTO PA/WESTERN NY WITH THE AXIS OF DILATATION
ORIENTED ALONG THE INTERNATIONAL BORDER AND IS CLEARLY ON WATER
VAPOR AND IR IMAGERY. AS THE CUT-OFF LOW SLOWLY ADVANCES
EASTWARD THIS AFTERNOON INTO TONIGHT, THE CONVEYOR BELT OF DEEP
SOUTHERLY WINDS (25-30KTS) WILL DIRECT THE MOISTURE PLUME
CHARACTERIZED BY PWAT VALUES 1 - 1.5 INCHES INTO THE NORTHEAST,
INCLUDING EASTERN NY AND WESTERN NEW ENGLAND. AS A RESULT, THE
COVERAGE OF AREAS OF SHOWERS AND EMBEDDED POCKETS OF
MODERATE/STEADY RAIN WILL INCREASE AND EXPAND OVER OUR AREA.
THEREFORE, POPS QUICKLY TREND UPWARDS (75 - 90%) THIS AFTERNOON
AND REMAIN HIGH 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 /MONDAY THROUGH TUESDAY NIGHT/
KEY MESSAGE:
- PERIODS OF RAIN WILL CONTINUE, SOME OF WHICH COULD BE HEAVY
AT TIMES, ESPECIALLY LATE MONDAY INTO TUESDAY.
DISCUSSION:
VERY LITTLE MOVEMENT IN THE PATTERN IS EXPECTED TONIGHT INTO
MONDAY, AS THE CUT-OFF LOW REMAINS PARKED OVER THE OHIO VALLEY,
WHILE A MOIST SOUTHERLY FLOW CONTINUES ALONG THE EAST COAST. AT
THE SURFACE, A STATIONARY FRONT IS EXPECTED TO REMAIN
POSITIONED NEAR THE I-84 CORRIDOR. PWAT ANOMALIES OF +1 TO +2
STDEV PERSIST AT WELL. SO PERIODS OF RAIN WILL CONTINUE,
SOME OF WHICH WILL BE MODERATE TO HEAVY AT TIMES. HOWEVER, THERE
IS LOWER CONFIDENCE IN DETAILS OF WHEN EXACT TIMING OF BETTER
FORCING OCCURS. THE ONLY CHANGE IN THE PATTERN ON MON IS A
NOTABLE AREA OF HIGH PRESSURE TRACKING SOUTH ACROSS THE CANADIAN
MARITIMES, WHICH WILL ALLOW THE STATIONARY FRONT TO PUSH
SLIGHTLY FARTHER SOUTH. THIS WILL RESULT IN A COOLER ONSHORE
EASTERLY FLOW. HIGHS MAY NOT GET OUT OF THE 50S IN HIGHER
TERRAIN AREAS AND ACROSS WESTERN NEW ENGLAND, WITH 60S IN THE
VALLEYS.
LIKELY/CATEGORICAL POPS CONTINUE THROUGH MON NIGHT WITH NO
DISCERNIBLE CHANGE IN THE PATTERN. MOIST, ONSHORE FLOW CONTINUES
WITH CONTINUED ABOVE NORMAL MOISTURE BUT LIMITED INSTABILITY
RESULTING IN ROUND OF RAIN AND COOL TEMPERATURES. LOWS SHOULD
RANGE FROM THE UPPER 40S TO MID 50S. MAX 6-HOURLY RAINFALL
AMOUNTS LOOK TO BE AROUND 0.50-0.75" SO WHILE 3-DAY TOTALS
EXCEED 2+ INCHES, RAIN SPREAD OUT OVER A FEW DAYS AND NOT OVERLY
HEAVY IN ANY SHORT PERIOD SHOULD LIMIT FLOODING THREAT. SEE
HYDRO SECTION FOR DETAILS.
UPPER LEVEL LOW LOOKS TO GRADUALLY SHIFT NORTHEAST TOWARD THE
REGION TUESDAY AND TUESDAY NIGHT. COOLING ALOFT, HEIGHT FALLS
AND INCREASING UPPER LEVEL DIFFLUENT FLOW MAY ALLOW FOR MORE
CONVECTIVE NATURE TO PRECIPITATION DURING THIS TIME PERIOD, WITH
SOME THUNDERSTORMS AND HEAVY DOWNPOURS POSSIBLE. SHOWERS AND
THUNDERSTORMS SHOULD DECREASE IN COVERAGE LATER TUESDAY NIGHT.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
KEY MESSAGE:
- TRENDING DRIER FOR THE END OF THE WEEK WITH BELOW NORMAL
TEMPERATURES.
DISCUSSION:
LONG TERM PERIOD BEGINS AT 12Z WEDNESDAY WITH THE UPPER LOW EXPECTED
TO TRACK ACROSS EASTERN NY INTO NEW ENGLAND. AT THE SAME TIME, A
DEVELOPING SFC LOW WILL TRACK OFF TO THE NORTHEAST OF OUR REGION.
THERE WILL STILL BE SOME LINGERING SHOWERS AROUND WEDNESDAY,
ESPECIALLY NORTH AND EAST OF THE CAPITAL DISTRICT. A COUPLE RUMBLES
OF THUNDER CAN'T BE RULED OUT WITH SOME POCKETS OF INSTABILITY AS
THE COLD POOL ALOFT MOVES OVERHEAD AS WELL. HOWEVER, WITH THE DEEPER
MOISTURE OFF TO OUR EAST AND A BRIEF PERIOD OF SUBSIDENCE BEHIND THE
DEPARTING UPPER LOW, SHOWERS WILL NOT BE AS WIDESPREAD OR AS HEAVY
AS ON TUESDAY. HIGHS WILL BE MAINLY IN 60S. WEDNESDAY NIGHT, AN
UPPER TROUGH DIGGING INTO THE EASTERN GREAT LAKES WILL FURTHER HELP
TO KICK THIS UPPER LOW OFF TO OUR EAST, WHILE AT THE SAME TIME
HELPING TO DRIVE A COLD FRONT INTO OUR REGION. LOWS DROP INTO THE
40S TO LOW 50S, WITH PRECIP CHANCES CONTINUING TO TREND DOWNWARDS
INTO THE SLIGHT CHANCE RANGE.
THURSDAY THROUGH FRIDAY NIGHT...THE COLD FRONT TRACKS OFF TO THE
SOUTH OF OUR REGION BY THURSDAY AFTERNOON. MEANWHILE, THE UPPER
TROUGH CONTINUES TO DIG SOUTHEASTWARDS, EVENTUALLY CLOSING OFF ALOFT
AND BECOMING CUTOFF FROM THE FLOW SOMEWHERE OVER NY OR NEW ENGLAND.
WHERE EXACTLY THIS FEATURE TRACKS REMAINS UNCERTAIN, BUT SINCE IT
WILL BE ASSOCIATED WITH AN UNUSUALLY COLD AIRMASS ALOFT (850 TEMPS
POTENTIALLY AS COLD AS -3 TO -5C OVER OUR AREA), WE WILL LIKELY SEE
BELOW NORMAL TEMPERATURES WITH DAYTIME HIGHS IN THE 50S (TERRAIN) TO
MID 60S (VALLEYS). OVERNIGHT LOWS WILL BE IN THE 30S TO LOW 40S, AND
SOME OF THE NORMALLY COLDER HIGH-TERRAIN AREAS COULD SEE LOWS NEAR
FREEZING ONE OR BOTH NIGHTS. AS FOR PRECIP CHANCES, ISOLATED TO
POSSIBLY SCATTERED DAYTIME SHOWERS WILL BE POSSIBLE WITH THE UPPER
LOW AND COLD POOL ALOFT OVERHEAD. IF THE UPPER LOW INTERACTS/PHASES
WITH UPPER SHORTWAVE ENERGY TRACKING OUT OF THE OHIO VALLEY, THEN AN
AREA OF LOW PRESSURE COULD DEVELOP OFF THE NEW ENGLAND COAST, BUT AT
THIS TIME IT LOOKS LIKE IF THIS HAPPENS, THE RESULTING SURFACE LOW
WILL BE TOO FAR TO OUR SOUTH AND EAST FOR MORE WIDESPREAD
RAIN/SHOWERS.
SATURDAY AND SATURDAY NIGHT...WHILE CONFIDENCE IS LOW ON THE TIMING,
WE ARE EXPECTING THE UPPER LOW TO BEGIN MOVING OFF TO OUR EAST. THIS
WILL ALLOW FOR DECREASING PRECIP CHANCES SATURDAY, AND TEMPERATURES
WARMING TO NEAR OR EVEN SLIGHTLY ABOVE NORMAL FOR DAYTIME HIGHS AND
OVERNIGHT LOWS. LOOKING AHEAD TO DAYS 8-14, THE CPC IS LEANING
TOWARDS ABOVE NORMAL TEMPERATURES AND BELOW NORMAL PRECIP.
AVIATION /18Z 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. DEFINITE SHRA...TSRA.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
THURSDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
HYDROLOGY
PERIODS OF RAIN ARE THEN EXPECTED TODAY THROUGH WEDNESDAY, WITH
SOME LOCALLY HEAVY RAIN POSSIBLE, ESPECIALLY LATE MONDAY INTO
TUESDAY. THIS MAY LEAD TO SOME FLOODING OF POOR DRAINAGE AND
URBAN AREAS AND ISOLATED FLASH FLOODING.
DESPITE CUMULATIVE RAINFALL AMOUNTS OF 1-3+ INCHES THROUGH
MIDWEEK, CURRENT 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, AND
SIGNIFICANT UPTAKE OF GREENING VEGETATION WILL LIKELY OFFSET
EXCESSIVE RUNOFF FROM THIS RAINFALL. HOWEVER, SHOULD GREATER
RAINFALL AMOUNTS (IN EXCESS OF 3-4 INCHES) OCCUR, PROBABILITIES
OF RIVER FLOODING WOULD INCREASE. TRENDS WILL BE WATCHED AS WE
GET CLOSER TO THE HEAVIEST RAINFALL POTENTIAL.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...KL/SPECIALE
NEAR TERM...KL/SPECIALE
SHORT TERM...KL
LONG TERM...MAIN
AVIATION...GITRO
HYDROLOGY...KL/JPV
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