074  
FXUS61 KALY 262042  
AFDALY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE ALBANY NY  
442 PM EDT WED JUL 26 2017  
   
SYNOPSIS
 
 
AN APPROACHING FRONTAL SYSTEM WILL BRING SOME SHOWERS  
AND THUNDERSTORMS LATE TONIGHT INTO THURSDAY. DRY WEATHER IS  
EXPECTED FOR MOST OF THE AREA FRIDAY INTO THE WEEKEND; HOWEVER, SOME  
RAINFALL IS POSSIBLE ACROSS FAR SOUTHERN AREAS AS LOW PRESSURE  
PASSES BY TO THE SOUTH. TEMPERATURES WILL REMAIN A BIT COOLER THAN  
NORMAL.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
AS OF 430 PM, SKIES RANGE FROM MOSTLY SUNNY IN THE HUDSON  
VALLEY NORTH OF CATSKILL TO MOSTLY CLOUDY OVER THE MOHAWK VALLEY  
AND SOUTHERN ADIRONDACKS. A GOOD COVERAGE OF DIURNAL CUMULUS  
HAS SPROUTED UP OVER THE HIGHER TERRAIN EAST OF THE HUDSON AS  
WELL. A BROAD EXPANSE OF CIRRUS IS APPROACHING FROM THE WEST.  
THIS SHOULD ENSURE THAT CLOUD FRACTION WILL STAY THE SAME OR  
INCREASE INTO THE EVENING FOR MOST AREAS.  
 
HIGH CLOUDS WILL CONTINUE TO THICKEN AND LOWER TONIGHT AS  
MIDLEVEL HEIGHTS GRADUALLY FALL AND INCREASED MIDLEVEL THETA-E  
WASHES INTO THE AREA. WEAK ASCENT PROVIDED BY THE HEIGHT FALLS  
AND MOISTURE ADVECTION WILL LIKELY ALLOW FOR SOME SHOWERS TO  
BREAK OUT, ESPECIALLY NORTH OF THE CAPITAL DISTRICT, BUT WILL  
HAVE SOME DRY AIR TO CONTEND WITH. SO HAVE GONE WITH A MORE  
GRADUAL INCREASE IN POPS FROM NORTH TO SOUTH TONIGHT, WITH BEST  
CHANCES ACROSS THE NORTH AFTER 06Z. LOWS ARE EXPECTED TO BE  
MILDER THAN THE PAST COUPLE OF NIGHTS WITH LIGHT SOUTHERLY FLOW  
AND INCREASING CLOUD COVER. COOLEST TEMPS MAY BE FOUND ACROSS  
THE FAR SOUTH WHERE IT WILL TAKE LONGEST TO CLOUD UP.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/
 
 
WEAK MIDLEVEL HEIGHT FALLS WILL CONTINUE THURSDAY AS A BROAD  
UPPER TROUGH SWEEPS INTO THE REGION. A WEAK SURFACE COLD FRONT,  
TIED TO A SURFACE LOW IN NORTHERN QUEBEC, WILL ALSO PUSH INTO  
THE FORECAST AREA. A SEASONABLY MOIST AIRMASS WILL WASH INTO THE  
REGION FROM THE WEST AHEAD OF THE FRONT, CHARACTERIZED BY PWATS  
IN THE 1.50-1.75 INCH RANGE. MODEL CONSENSUS SUGGESTS AREAS OF  
RAINFALL ASSOCIATED WITH THETA-E ADVECTION AND MIDLEVEL HEIGHT  
FALLS TO EXPAND SOUTHWARD AND IMPACT THE NORTHERN 2/3 OF OUR  
FORECAST AREA BETWEEN 12-18Z. THE EXPECTED CLOUD COVER AND  
RAINFALL WILL LIMIT DESTABILIZATION, WITH EVEN THE TYPICALLY  
BULLISH NAM STRUGGLING TO GENERATE MLCAPE VALUES OF 1000 J/KG  
DURING THE AFTERNOON DESPITE DEWPOINTS RISING INTO THE MID TO  
UPPER 60S. THE GFS GENERATES LITTLE TO NO SURFACE-BASED  
INSTABILITY FOR THE MAJORITY OF THE FORECAST AREA. EVEN IF SOME  
INSTABILITY DEVELOPS WITH MUTED SURFACE HEATING, CONVERGENCE  
ALONG THE FRONT APPEARS TO WEAKEN BY THE AFTERNOON HOURS AS THE  
FRONT WASHES OUT. SO, WHILE AN ISOLATED STRONGER STORM CANNOT BE  
RULED OUT, ESPECIALLY IN THE AFTERNOON, AN ORGANIZED SEVERE  
WEATHER EVENT APPEARS UNLIKELY. LOCALLY HEAVY RAINFALL WILL BE A  
THREAT, GIVEN MIDLEVEL WINDS NEARLY PARALLEL TO LOW-LEVEL  
BOUNDARY, ALONG WITH THE MOIST ATMOSPHERE. HOWEVER, UNCERTAINTY  
WITH RESPECT TO CONVECTIVE COVERAGE AS WELL AS FAIRLY FAST  
PRECIP MOTION SHOULD MITIGATE THE THREAT SOMEWHAT. HAVE GONE  
WITH A BLEND OF THE COOLER MAV AND WARMER MET GUIDANCE FOR  
HIGHS, YIELDING UPPER 60S TO UPPER 70S.  
 
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN  
POSSIBLE EARLY THURSDAY NIGHT OVER SOUTHERN PORTIONS OF THE AREA  
BEFORE DRIER AIR BUILDS IN ON NORTHWEST FLOW AS HIGH PRESSURE  
BEGINS TO NOSE IN. CAN'T RULE OUT SOME FOG IF CLEARING DEVELOPS,  
ESPECIALLY IN AREAS THAT SEE RAINFALL THURSDAY. LOWS NEAR TO A  
BIT ABOVE NORMAL IN THE UPPER 50S TO UPPER 60S.  
 
FRIDAY INTO SATURDAY, A VIGOROUS, COMPACT UPPER LOW WILL MOVE FROM  
THE WESTERN GREAT LAKES TO THE MID-ATLANTIC COAST. A SEASONABLY  
STRONG SURFACE LOW WILL DEVELOP AHEAD OF THIS FEATURE IN THE  
LEE OF THE MID-ATLANTIC APPALACHIANS AND TRACK INTO THE ATLANTIC  
SOUTH OF CAPE COD BY 00Z SUNDAY. STILL CONSIDERABLE MODEL  
SPREAD WITH THE TRACK OF THE SURFACE LOW AND THE NORTHERN EXTENT  
OF ITS ASSOCIATED PRECIP SHIELD. CONSENSUS DOES FAVOR THE  
MAJORITY OF THE PRECIPITATION REMAINING SOUTH OF THE LOCAL  
FORECAST AREA; HOWEVER, THE NORTHERN FRINGE COULD REACH OUR  
SOUTHERN TWO TIERS OF COUNTIES FRIDAY AFTERNOON INTO FRIDAY  
NIGHT. HEAVY RAINFALL THREAT AT THIS TIME LOOKS TO SET UP SOUTH  
OF OUR FORECAST AREA, BUT A FEW OUTLYING SREF/GEFS MEMBERS  
INDICATE HEAVY RAINFALL EXTENDING INTO OUR FAR SOUTHERN  
COUNTIES. HOWEVER, THE TREND IN THE GEFS HAS BEEN DRIER. AT THIS  
POINT, WILL CONTINUE TO TOE THE LINE WITH CHANCE POPS UNTIL  
BETTER MODEL CONSENSUS CAN BE REACHED. FOR THE REMAINDER OF THE  
FORECAST AREA, RELATIVELY PLEASANT WEATHER CAN BE EXPECTED, WITH  
HIGHS IN THE UPPER 60S TO UPPER 70S (A BIT BELOW NORMAL). HAVE  
SIDED WITH THE COOLER MET MOS FOR HIGHS ON FRIDAY GIVEN THAT THE  
GFS APPEARS TO BE A SLOW OUTLIER WITH THE SYSTEM, PROVIDING  
AMPLE SUNSHINE AND WARMER TEMPS FOR MUCH OF OUR FORECAST AREA.  
COULD BE A BIT BREEZY SATURDAY FOR THIS TIME OF YEAR ON THE BACK  
SIDE OF THE LOW. NORTHERLY WINDS WILL ALLOW H850 CAA TO OCCUR,  
DROPPING TEMPS TO THE UPPER SINGLE DIGITS CELSIUS.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
WE FINALLY HAVE A STRETCH OF PLEASANT WEATHER IN STORE FOR US IN THE  
LONG TERM. TEMPERATURES START OUT NEAR NORMAL BUT RISE TO THE ABOVE  
NORMAL SIDE OF THE SPECTRUM WITH EACH PASSING DAY AND PRECIPITATION  
LOOKS TO BE BELOW NORMAL DUE WEAK FORCING AND PALTRY UPPER LEVEL  
MOISTURE, BASED ON THE CURRENT MODEL SUITE.  
 
SENSIBLE WEATHER ON SUNDAY IS CONTINGENT ON JUST HOW FAST A POTENT  
COASTAL LOW OFF THE NJ/S. NEW ENGLAND COAST DEVELOPS AND DEPARTS  
OVER THE WEEKEND. AT THIS TIME, THE LOW SHOULD BE WELL SOUTH OF OUR  
CWA WITH HIGH PRESSURE ANCHORED OVER NY/NORTHERN NEW ENGLAND KEEPING  
MOST OF OUR REGIONS DRY UNDER NORTHERLY WINDS. HAVE LEFT CLOUDIER  
SKIES/COOLER TEMPERATURES (UPPER 70S) FOR THE SOUTHERN/EASTERN TIER  
AREAS AND CLEARER SKIES/SLIGHTLY WARMER TEMPERATURES (NEAR 80)  
ELSEWHERE BASED ON THIS THINKING.  
 
BY MONDAY, HIGH PRESSURE SHOULD BE IN CONTROL OVER OUR CWA WITH  
TEMPERATURES WARMING TO NORMAL EVERYWHERE. TUESDAY THE HIGH SHIFTS  
FURTHER EASTWARD WITH A WEAK TROUGH DIPPING OUT OF CANADA INTO  
NORTHERN NEW ENGLAND. CURRENT GUIDANCE SHOWS WEAK FORCING WITH THE  
BASE OF THE TROUGH BARELY REACHING OUR CWA WITH LITTLE IN THE WAY OF  
H700 MOISTURE. THUS, HAVE ONLY PLACED SLIGHT CHANCE POPS IN OUR CWA,  
MAINLY NORTHERN/ELEVATED AREA. WITH THE HIGH SITUATED FURTHER EAST  
GIVING US MORE WESTERLY FLOW, CAPE VALUES LOOK TO INCREASE ABOVE  
500J/KG SO PLACED SLIGHT CHANCE THUNDER AS WELL FOR TUESDAY.  
 
WEDNESDAY - THURSDAY TURN WARMER AND MORE HUMID AS HIGH PRESSURE  
SHIFTS EVEN FURTHER EASTWARD AND SOUTHWESTERLY FLOW TAKES OVER THE  
REGION. TEMPERATURES SHOULD RISE INTO THE MID 80S THROUGHOUT THE CWA  
WITH DEW POINTS RETURNING TO THE 60S. THE H500 FLOW SHOWS ZONAL/WEAK  
RIDGING OVER THE NORTHEAST DURING THIS PERIOD AHEAD OF THE NEXT,  
STRONGER TROUGH APPROACHING LATE IN THE WEEK. ON WEDNESDAY, GUIDANCE  
SUGGESTS VERY WEAK SHORTWAVES EMBEDDED IN THE UPPER LEVEL  
ATMOSPHERIC FLOW WHICH MEANS A FEW ISOLATED AFTERNOON STORMS ARE NOT  
RULED OUT. THE AFOREMENTIONED TROUGH SHOULD DRAG A COLD FRONT LATE  
THURSDAY/THURSDAY EVENING AND GUIDANCE DOES SHOW A DECENT THERMAL  
GRADIENT SO THAT TIME PERIOD HAS A HIGHER THREAT FOR  
SHOWERS/STORMS.  
 

 
   
AVIATION /21Z WEDNESDAY THROUGH MONDAY/
 
 
EXPECT MAINLY VFR CONDITIONS TO HOLD THROUGH EARLY THURSDAY  
MORNING AT ALL TERMINALS. THERE COULD BE SOME LIGHT SHRA  
ACTIVITY ASSOCIATED WITH WEAKENING CONVECTION ACROSS THE GREAT  
LAKES FOR TONIGHT AT KGFL. HAVE THIS COVERED AT KGFL WITH VCSH.  
 
PROSPECTS FOR RAINFALL INCREASE ON THURSDAY AS A FRONTAL SYSTEM  
APPROACHES THE REGION. EXPECT MVFR CONDITIONS IN CEILINGS AND  
VISIBILITIES TO TAKE HOLD NORTH TO SOUTH THURSDAY MORNING. NOT  
OUT OF THE QUESTION THAT THERE COULD BE A BRIEF PERIOD OF IFR,  
BUT DO NOT SEE IT NOW.  
 
OUTLOOK...  
 
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.  
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
 

 
   
FIRE WEATHER
 
 
SHOWERS AND THUNDERSTORMS WILL BECOME LIKELY ONCE AGAIN  
THURSDAY, ESPECIALLY NORTH OF THE MID-HUDSON VALLEY. DRIER  
WEATHER TAKES HOLD FRIDAY INTO THE WEEKEND, ALTHOUGH PERIODS OF  
RAINFALL MAY IMPACT AREAS SOUTH OF THE CAPITAL DISTRICT FRIDAY  
AND FRIDAY NIGHT. TEMPERATURES WILL COME UP SHORT OF NORMAL  
VALUES. RH VALUES WILL BOTTOM OUT IN THE 55 TO 65 PERCENT RANGE  
FRIDAY, AND BECOME DRIER SATURDAY IN THE 40 TO 50 PERCENT  
RANGE. NORTHERLY WINDS MAY BECOME A BIT GUSTY SATURDAY TO NEAR  
25 MPH.  
 

 
   
HYDROLOGY
 
 
PERIODS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY INTO  
EARLY THURSDAY NIGHT. BASIN AVERAGE RAINFALL IS EXPECTED TO  
REMAIN BELOW A HALF INCH; HOWEVER, LOCALLY HEAVY RAINFALL WILL  
BE POSSIBLE IN ANY THUNDERSTORM. ISOLATED URBAN AND POOR-  
DRAINAGE FLOODING CANNOT BE RULED OUT IN AREAS THAT SEE REPEATED  
ROUNDS OF RAINFALL.  
 
CONDITIONS WILL GENERALLY BE DRY FRIDAY INTO THE WEEKEND, BUT  
SOME PERIODS OF RAINFALL MAY IMPACT AREAS SOUTH OF THE CAPITAL  
DISTRICT FRIDAY AFTERNOON INTO FRIDAY NIGHT. LATEST INDICATIONS  
ARE THAT AMOUNTS WILL REMAIN ON THE LIGHT SIDE; HOWEVER, THERE  
IS A LOW PROBABILITY THAT THE ASSOCIATED STORM TRACK WILL SHIFT  
NORTH AND BRING MORE OF A SOAKING RAIN TO SOUTHERN PORTIONS OF  
THE FORECAST AREA.  
 
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...THOMPSON  
NEAR TERM...THOMPSON  
SHORT TERM...THOMPSON  
LONG TERM...SPECIALE  
AVIATION...OKEEFE  
FIRE WEATHER...THOMPSON  
HYDROLOGY...THOMPSON  
 
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