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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