147
FXUS61 KALY 241446
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1046 AM EDT SUN OCT 24 2021
SYNOPSIS
SEASONABLY COOL TEMPERATURES TODAY WITH INCREASING CLOUDS THIS
AFTERNOON. A PERIOD OF STEADY RAIN IS EXPECTED TONIGHT AHEAD OF
A WARM FRONT. THE FRONT STALLS NEAR INTERSTATE 90 TOMORROW,
RESULTING IN COOL, CLOUDY CONDITIONS TO THE NORTH WITH MILDER
AIR TO THE SOUTH. THEN, AREAS OF RAIN ARE EXPECTED MONDAY NIGHT
THROUGH TUESDAY NIGHT. DRY WEATHER BRIEFLY RETURNS FOR THE END
OF THE WEEK BEFORE UNSETTLED CONDITIONS RETURN THIS WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 10:15 AM...CHILLY START TO THE DAY. WE ISSUED A PUBLIC
INFORMATION STATEMENT WITH THIS MORNING'S LOW TEMPERATURES; IN
THE 20S AND 30S WITH SOME LOWER TO MID 40S NEAR THE HUDSON RIVER
IN THE MID-HUDSON VALLEY. THE COLDEST LOCATION IN OUR COUNTY
WARNING AREA WAS OLD FORGE WITH 24 DEGREES.
FORECAST REMAINS ON TRACK. STRATUS AND FOG LIFTED AND BURNED OFF
QUICKLY THIS MORNING. LOOKING AT SEASONABLY COOL TEMPERATURES
WITH HIGHS THIS AFTERNOON EXPECTED TO FALL A BIT SHORT OF
NORMAL FOR LATE OCTOBER. EXPECTING FAIR WEATHER WITH INCREASING
CLOUDS THIS AFTERNOON AHEAD OF AN APPROACHING WARM FRONT. MINOR
ADJUSTMENTS WERE MADE WITH OBSERVATIONAL DATA AND BLENDED WITH
LATEST GUIDANCE.
PREVIOUS DISCUSSION...SURFACE HIGH PRESSURE COMBINED WITH
UPPER LEVEL RIDGING WILL SUPPORT SUNNY SKIES THIS MORNING BUT
FORECAST SOUNDINGS SUGGEST THAT BOUNDARY LAYER MIXING TODAY WILL
BE SHALLOW, ONLY REACHING UP TO ABOUT 925HPA. SO, DESPITE THE
SUNSHINE TODAY, LIMITED MIXING AND THE CHILLY START WILL GIVE US
ANOTHER COOL DAY TODAY WITH HIGH TEMPERATURES ONLY REACHING
INTO THE LOW TO MID 50S.
SUN BECOMES FILTER BY GRADUALLY INCREASING AFTERNOON CLOUDS AS
OUR RIDGE AXIS SHIFTS INTO NEW ENGLAND. A SHORTWAVE TROUGH AND
ITS ASSOCIATED SURFACE LOW IN THE MIDWEST WILL BECOME
VERTICALLY STACKED AS IT MATURES TONIGHT WITH STRONG ISENTROPIC
LIFT AHEAD OF ITS WARM FRONT. IN ADDITION, EASTERN NY AND
WESTERN NEW ENGLAND WILL BE IN THE EQUATORWARD ENTRANCE REGION
OF A ~130KT JET POSITIONED ACROSS NORTHERN NEW ENGLAND INTO THE
CANADIAN MARITIMES WHICH WILL PROVIDE ADDITIONAL FORCING FOR
ASCENT. AS A RESULT, EXPECT A PERIOD OF RAIN TO OVERSPREAD THE
REGION TONIGHT BETWEEN 02 UTC AND 07 UTC FIRST REACHING THE
EASTERN CATSKILLS AND MOHAWK VALLEY BEFORE EXPANDING
NORTHEASTWARD INTO THE CAPITAL DISTRICT, UPPER HUDSON VALLEY AND
WESTERN NEW ENGLAND. PWAT VALUES NEAR 1.25" AFTER 06 UTC SO
RAINFALL WILL LIKELY BECOME MODERATE AT TIMES. TOTAL RAINFALL
AMOUNTS THROUGH 12 UTC MONDAY RANGE BETWEEN 0.25 AND 0.75"
THROUGHOUT THE AREA.
BETWEEN THE INCREASING CLOUDS AND INCOMING RAINFALL, TEMPERATURES
TONIGHT WILL BE RATHER MILD ONLY DROPPING INTO THE LOW TO MID
40S. UPPER 30S IN THE SOUTHERN ADIRONDACKS AND SOUTHERN VERMONT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
RAIN MONDAY MORNING WILL BECOME LESS ORGANIZED AND TRANSITION
INTO SCATTERED SHOWERS BEFORE WINDING DOWN AS THE SURFACE LOW
IN THE MIDWEST WEAKENS. ITS ASSOCIATED WARM FRONT WILL BE
ADVANCING NORTHWARD TOWARD THE I-90 CORRIDOR BUT WITH THE LOW
WEAKENING OVER LAKE ERIE AND A BLOCKING ~1030HPA HIGH OVER THE
HUDSON BAY, GUIDANCE CONTINUES TO SUGGEST THE FRONT STALLS NEAR
THE INTERSTATE. AS A RESULT, THE TEMPERATURE FORECAST MONDAY
REMAINS CHALLENGING. THE WARM SECTOR LOOKS LIKE IT PENETRATE
INTO THE MID-HUDSON VALLEY, NW CT AND PARTS OF GREENE/COLUMBIA
COUNTIES ALLOWING TEMPERATURES TO REACH INTO THE MID TO UPPER
60S; HOWEVER, A SHARP TEMPERATURE GRADIENT WILL SET-UP TO THE
NORTH WHERE NORTH-NORTHEAST WINDS PERSIST AHEAD OF THE STALLED
BOUNDARY, MAINTAINING CHILLY TEMPERATURES IN THE UPPER 40S TO
MID-50S. THE ENSEMBLE MOS GUIDANCE CONTINUES TO POINT TO A WIDE
SPREAD BETWEEN THE 10TH, 50TH AND 90TH PERCENTILE OWING TO
ONGOING UNCERTAINTY IN THE EXACT POSITION OF THE WARM FRONT. WE
SIDED WITH THE COOLER SIDE OF THE ENVELOPE SINCE THERE ARE MORE
FACTORS IN PLACE THAT SUGGEST THE FRONT WILL STRUGGLE TO LIFT
NORTHWARD ACROSS OUR AREA. BESIDES A COOL AND CLOUDY DAY,
CONTINUED WEAK WARM AIR ADVECTION IN THE VICINITY OF THE
BOUNDARY SHOULD SUPPORT SOME CONTINUED ISOLATED SHOWERS OR
DRIZZLE FOR MOST OF THE AREA SO WE CONTINUED TO CARRY CHANCE
POPS MOST OF THE DAY.
WHILE THE PARENT SFC LOW WEAKENS, NORTHERN STREAM SHORTWAVE
ENERGY OVER THE NORTHERN GREAT LAKES LOOKS TO INTERACT WITH THE
REMNANT SHORTWAVE OVER THE OHIO VALLEY, ALLOWING IT TO BECOME
NEGATIVELY TILTED AND INDUCING CYCLOGENESIS OFF THE MID-ATLANTIC
COAST MONDAY NIGHT. AS A RESULT, GUIDANCE CONTINUES TO SHOW A
SECONDARY COASTAL LOW DEVELOPING (POTENTIALLY BECOMING A DOUBLE
BARREL LOW) AND TRACKING TOWARDS THE NORTHEAST. THIS WOULD
SUPPORT A PERIOD OF MODERATE RAIN WITHIN ITS PRECIPITATION
SHIELD, ENHANCED BY A POTENTIAL INVERTED TROUGH, TO IMPACT THE
AREA LATE MONDAY NIGHT INTO MOST OF THE DAY TUESDAY. HOWEVER,
THERE REMAINS DISCREPANCIES AMONG THE GLOBAL GUIDANCE ON THE
EXACT TRACK AND PLACEMENT OF THIS LOW WHICH KEEPS CONFIDENCE IN
THE STORM TOTAL RAINFALL AMOUNTS LOW. THE ECMWF IS STILL THE
WETTEST SOLUTION AS IT IS ROBUST WITH IMPACTS FROM THE INVERTED
TROUGH WHILE THE GFS ACTUALLY TRENDED DRIER, AS IT KEEPS THE
SECONDARY LOW FURTHER SOUTH/EAST OFF THE COAST OF LONG ISLAND
AND NJ. THE CMC AND NAM RESEMBLE THE ECWMF IN TERMS OF OVERALL
STORM TRACK BUT ARE NOT NEARLY AS WET. DESPITE UNCERTAINTY WITH
THE STORM TRACK, GUIDANCE IS IN GOOD AGREEMENT IN STRONG SOUTH-
SOUTHWESTERLY WINDS STRENGTHENING OFF THE EAST COAST WHICH
WOULD SUPPORT HIGH MOISTURE TRANSPORT WITH WINDS TAPPING INTO
MOISTURE FROM THE WESTERN ATLANTIC AND EVEN GULF OF MEXICO. IN
ADDITION TO A RICH MOISTURE PLUME, GUIDANCE POINTS TO A DUAL
JET STRUCTURE FORMING AS THE SECONDARY LOW DEVELOPS OFF SHORE
WHICH WOULD PROVIDE ADDITIONAL FORCING FOR ASCENT. THEREFORE,
THE NECESSARY INGREDIENTS LOOK TO BE IN PLACE FOR THIS STORM
SYSTEM TO GENERATE MODERATE TO EVEN HEAVY RAINFALL...IT'S JUST
A QUESTION OF IF THE SYSTEM TRACKS FAR ENOUGH INLAND FOR ITS
PRECIPITATION SHIELD TO IMPACT EASTERN NY AND WESTERN NEW
ENGLAND OR IF IT REMAINS OFF SHORE OR MAINLY IMPACTS LONG
ISLAND/SOUTHERN NEW ENGLAND. FOR NOW, WE CONTINUE TO SHOW ABOUT
1 TO 3 INCHES OF RAINFALL WITH THE HIGHEST POPS FROM 06 UTC TUES
TO 06 UTC WED. THERE ARE HINTS THAT SUFFICIENT INSTABILITY FROM
THE MOISTURE PLUME COULD SUPPORT SOME ISOLATED CONVECTION BUT
GUIDANCE SUGGESTS THE BETTER CHANCES FOR THIS STAY SOUTH/EAST OF
OUR AREA.
OTHERWISE, TUESDAY WILL LIKELY BE COOL AND DREARY AND WE SIDED
WITH THE COOLER SIDE OF THE ENVELOPE WITH HIGHS STRUGGLING TO
RISE OUT OF THE 50S DUE TO PERSISTENT NORTH-NORTHEAST SFC WINDS.
WINDS COULD BECOME A BIT BREEZY TUESDAY NIGHT AS THE SECONDARY
LOW EXITS AND THE PRESSURE GRADIENT IN ITS WAKE TIGHTENS
OVERHEAD. OTHERWISE, RAIN TUESDAY NIGHT SHOULD WIND DOWN WITH
LOWS STAYING SEASONABLY MILD IN THE UPPER 40S TO NEAR 50.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
THE LONG TERM WILL CONSIST OF OUR FIRST STORM DEPARTING THE REGION
WITH A MAINLY DRY STRETCH TO END THE WEEK. THE NEXT STORM WILL
ARRIVE FOR NEXT WEEKEND WITH MORE WIDESPREAD RAINFALL.
OUR NEARLY VERTICALLY-STACKED LOW NEAR OR OFF THE NORTHEAST US COAST
WILL SLOWLY DEPART TO THE EAST ON WEDNESDAY AS UPPER-LEVEL RIDGING
BUILDS IN FROM THE WEST. GUIDANCE CONTINUES TO DIFFER WHETHER OR NOT
PRECIPITATION LINGERS INTO PART OF THE DAY, HOWEVER, AND THIS IS
MOSTLY DUE TO SOME SLIGHT DIFFERENCES IN THE LOCATION OF THE LOW. WE
WILL GO WITH A GRADUAL DRYING TREND FROM WEST TO EAST DURING THE DAY
FOR NOW. ON THE OUTER PERIPHERY OF THE LOW, THERE WILL LIKELY BE A
NORTHERLY BREEZE, ESPECIALLY FOR THOSE ALONG THE HUDSON VALLEY AND
POINTS EAST. IT WILL REMAIN CLOUDY TO START; HOWEVER, SOME BREAKS OF
SUN MAY OCCUR LATE IN THE DAY. HIGH TEMPERATURES WEDNESDAY WILL
RANGE FROM THE LOWER TO MID-50S IN THE HIGHER TERRAIN TO THE UPPER
50S/LOWER 60S IN THE VALLEYS.
THE COMBINATION OF UPPER-LEVEL RIDGING AND SURFACE HIGH PRESSURE
NOSING IN FROM THE NORTH WILL RESULT IN DRIER, SEASONABLE WEATHER TO
END THE WEEK. HIGHS BOTH THURSDAY AND FRIDAY WILL REACH THE UPPER
40S/LOWER 50S IN THE HIGHER ELEVATIONS TO THE UPPER 50S/LOWER 60S IN
THE VALLEYS. LOWS BOTH WEDNESDAY AND THURSDAY NIGHT WILL BE IN THE
30S ACROSS THE HIGHER TERRAIN TO THE LOWER 40S IN THE VALLEYS.
THE SIGNIFICANT STORM SYSTEM SET TO IMPACT THE WESTERN US EARLY THIS
WEEK WILL TREK ACROSS THE CONUS AND REACH OUR REGION LATE FRIDAY
THROUGH THE WEEKEND WITH ADDITIONAL RAINFALL. THERE ARE SOME SLIGHT
DIFFERENCES IN THE ARRIVAL TIMING OF RAINFALL AMONGST GUIDANCE, BUT
OVERALL GUIDANCE SUGGESTS RAIN BEGINS LATE FRIDAY AFTERNOON OR
FRIDAY NIGHT. BECAUSE OF THIS, WE REDUCED POPS BELOW NBM GUIDANCE
DURING THE DAY FRIDAY AS IT APPEARED TO INCREASE RAIN CHANCES TOO
QUICKLY. ON AND OFF RAIN SHOWERS WILL THEN CONTINUE THROUGH THE
WEEKEND WITH THE SURFACE AND UPPER-LEVEL LOW SITTING AND SPINNING
OVER OUR REGION. LOWS FRIDAY NIGHT WILL BE MAINLY IN THE 40S WITH
HIGHS SATURDAY MOSTLY BETWEEN 50 AND 60.
AVIATION /15Z SUNDAY THROUGH THURSDAY/
THROUGH 06Z/MON...HIGH PRESSURE WILL GRADUALLY BUILD ACROSS THE
REGION FOR MUCH OF SUNDAY. A WARM FRONT WILL APPROACH THE REGION
WITH SOME RAIN SUNDAY EVENING.
THE TAF PERIOD WILL MAINLY CONSIST OF VFR CONDITIONS OUTSIDE OF SOME
PATCHY FOG FOR THE REMAINDER OF THE NIGHT AT KGFL/KPOU, WHICH HAS
ALREADY BEEN OBSERVED THIS EVENING. A TEMPO WAS INCLUDED FOR
POSSIBLE IFR/LIFR FOG AT THESE SITES. ELSEWHERE, MUCH OF THE PERIOD
WILL CONSIST OF PATCHY FAIR WEATHER CLOUDS ABOVE 4000 FEET.
RAIN WILL ARRIVE AT THE TAF SITES BETWEEN 03-06Z/MON WITH FLIGHT
CONDITIONS STARTING VFR BUT GRADUALLY LOWERING TO AT LEAST MVFR
AROUND OR SHORTLY AFTER 06Z/MON.
WIND WILL REMAIN LIGHT AND VARIABLE FOR THE REMAINDER OF THE
OVERNIGHT, THEN BE OUT OF THE SOUTHERLY TO WESTERLY DIRECTION AT 4-8
KT SUNDAY. WIND WILL BECOME LIGHT AND VARIABLE AGAIN SUNDAY
EVENING.
OUTLOOK...
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
TUESDAY: HIGH OPERATIONAL IMPACT. DEFINITE RA.
TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY RA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA.
FIRE WEATHER
AFTER A DRY SUNDAY WITH RH VALUES DROPPING TO 50 - 60 PERCENT
THIS AFTERNOON, AN AREA OF RAIN IMPACTS EASTERN NY AND WESTERN
NEW ENGLAND TONIGHT. ADDITIONAL SHOWERS OR INTERMITTENT DRIZZLE
CONTINUE MONDAY WITH MORE ORGANIZED RAINFALL ARRIVING MONDAY
NIGHT INTO THE DAY ON TUESDAY.
HYDROLOGY
TWO PERIODS OF RAINFALL ARE EXPECTED THIS WEEK. THE FIRST IS
TONIGHT RESULTING IN 0.25 TO 0.75 INCHES OF RAINFALL. THEN A
COASTAL LOW COULD RESULT IN A PERIOD OF RAIN, MODERATE TO
POSSIBLY HEAVY AT TIMES DEPENDING ON EXACT STORM TRACK, MONDAY
NIGHT INTO TUESDAY NIGHT. TOTAL RAINFALL AMOUNTS DURING THIS
SECOND EVENT COULD RANGE FROM 1 TO 3 INCHES. LATEST MMEFS
FORECASTS BASED ON THE NAEFS AND GEFS STILL POINT TO LOW TO
EVEN MODERATE PROBABILITIES OF FORECAST POINTS ALONG THE
HOUSATONIC, HOOSIC, WALLOOMSAC BASINS AS WELL AS PARTS OF THE
HUDSON REACHING FLOOD STAGE. CONFIDENCE IN EXACT RAINFALL
AMOUNTS AND THEREFORE RIVER FLOODING REMAINS LOW AS THERE
REMAINS A LARGE SPREAD IN THE STORM TOTAL QPF FORECAST.
AFTER A BRIEF PERIOD OF DRY WEATHER WEDNESDAY THROUGH FRIDAY,
ANOTHER SYSTEM MAY BRING PERIODS OF RAIN FRIDAY INTO NEXT
WEEKEND. THIS WILL HAVE TO BE CLOSELY MONITORED FOR ADDITIONAL
FLOODING POTENTIAL.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES, INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS, PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
ALY WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
SYNOPSIS...IAA/SPECIALE
NEAR TERM...IAA/SPECIALE
SHORT TERM...SPECIALE
LONG TERM...RATHBUN
AVIATION...RATHBUN
FIRE WEATHER...SPECIALE
HYDROLOGY...THOMPSON/SPECIALE
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