104  
FXUS61 KALY 181453  
AFDALY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE ALBANY NY  
1053 AM EDT MON JUN 18 2018  
   
SYNOPSIS
 
 
HOT AND HUMID CONDITIONS ARE IN STORE TODAY. SCATTERED  
SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON, BECOMING MORE  
WIDESPREAD THIS EVENING INTO TONIGHT WITH HEAVY RAINFALL AND GUSTY  
WINDS POSSIBLE. A MORE SEASONABLE AIRMASS TAKES OVER TUESDAY AND  
WEDNESDAY WITH MUCH LOWER HUMIDITY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
HEAT ADVISORY IN EFFECT FOR MOST ZONES BELOW 1000 FEET  
ELEVATION IN EASTERN NY AND SOUTHERN VT...  
 
SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND  
EVENING...  
 
SLIGHT RISK OF EXCESSIVE RAINFALL THIS AFTERNOON INTO  
TONIGHT...  
 
SPC HAS EXPANDED THE SLIGHT RISK FOR SEVERE WEATHER ACROSS THE  
ENTIRE FORECAST AREA THIS MORNING. THEREFORE, WE WILL HAVE AN  
17-18Z UPPER AIR BALLOON LAUNCH.  
 
AS OF 1040 AM EDT, MOST OF THE AREA HAS CLEARED OF CLOUD COVER  
THIS MORNING ALLOWING TEMPERATURES TO QUICKLY WARM INTO THE  
UPPER 70S AND LOWER 80S. DEW POINT TEMPERATURES HAVE ALSO  
INCREASED INTO THE MID 60S TO LOW 70S, FROM THE UPPER 50S EARLY  
THIS MORNING. WITH TEMPERATURES EXPECTED TO CLIMB INTO THE UPPER  
80S TO MID 90S AREA-WIDE TODAY, CONDITIONS WILL BE OPPRESSIVE  
AND DANGEROUS. WEATHER WISE, THE REMAINDER OF THE MORNING SHOULD  
REMAIN DRY. HOWEVER, LATEST CAMS INDICATE CONVECTION GETS GOING  
AROUND 18Z (2PM LOCAL TIME) ACROSS THE NORTHERN ZONES THEN  
TRAVERSES SOUTHWARD WITH THE PASSAGE OF THE PRE-FRONTAL TROUGH.  
THEN A SECOND ROUND OF CONVECTION LOOKS POSSIBLE WITH THE  
PASSAGE OF THE COLD FRONT CLOSER TO 22-02Z. SO IN TERMS OF THE  
FORECAST PACKAGE, HAVE ADJUSTED HOURLY TEMPS AND POPS IN THE  
NEAR-TERM TO REFLECT MOST RECENT OBS AND SENT UPDATES TO NDFD  
AND WEB SERVERS.  
 
PREV DISC...AS OF 640 AM, JUST A COUPLE OF SHOWERS FROM LEWIS  
COUNTY TO THE SYRACUSE AREA TRACKING EASTWARD. THESE ARE  
ASSOCIATED WITH ELEVATED WARM/MOIST ADVECTION AND INCREASING  
(ALBEIT WEAK) INSTABILITY. SLIGHT CHANCE POPS ADDED TO THE  
SOUTHERN ADIRONDACKS/WESTERN MOHAWK VALLEY FOR THE NEXT COUPLE  
HOURS TO ACCOUNT FOR THIS ACTIVITY. ELSEWHERE, TEMPS RANGE FROM  
UPPER 50S TO LOWER 70S. WARMTH AND MOISTURE IN THE FORM OF MID-  
60S TO UPPER 70S DEWPOINTS ARE ON THE DOORSTEP AND SHOULD BEGIN  
TO INVADE EASTERN NEW YORK THIS MORNING.  
 
PREVIOUS DISCUSSION...  
 
EARLY MORNING WATER VAPOR SHOWS CIRRUS/ALTOSTRATUS CONTINUING  
TO SPILL OVER THE UPPER LEVEL RIDGE INTO THE NORTHEASTERN US. ELEVATED  
WARM FRONT TRACKING WEST TO EAST THROUGH THE REGION EARLY THIS  
MORNING WITH H850 TEMPS FORECAST TO RISE TO 18-20C AS WINDS TURN  
WESTERLY. AT THE SURFACE, WEST TO EAST-ORIENTED COLD FRONT IS  
LOCATED WELL TO THE NORTH OVER CENTRAL QC AND SOUTHERN ON. MOIST  
PREFRONTAL AIRMASS WILL ADVECT INTO THE LOCAL AREA TODAY AS  
SURFACE WINDS TURN SOUTHWESTERLY. MID-60S TO LOWER 70S DEWPOINTS  
EXIST IN THIS AIRMASS, AND MODELS SUGGEST WE SHOULD ATTAIN  
THESE VALUES IN THE AFTERNOON. HEAT ADVISORY REMAINS IN EFFECT  
FOR MOST AREAS IN EASTERN NY AND SOUTHERN VT BELOW 1000 FEET  
ELEVATION AS FORECAST SOUNDINGS SHOW POTENTIAL TO MIX ABOVE 850  
MB AND SEND HIGH TEMPS INTO THE LOWER 90S. WILL ADD WESTERN  
ULSTER TO THE HEAT ADVISORY AS THE LOWER ELEVATIONS IN THAT ZONE  
SHOULD SEE CRITERIA MET. HOWEVER, THE DEGREE OF HEAT WILL BE  
DEPENDENT UPON COVERAGE OF AFTERNOON CONVECTION, WHICH WILL BE  
DISCUSSED BELOW.  
 
FORECAST AREA WILL REMAIN IN THE PREFRONTAL AIRMASS TODAY AS THE  
FRONT'S NORTH TO SOUTH TRACK THROUGH THE REGION WILL NOT OCCUR  
UNTIL AFTER 00Z. THIS SHOULD ALLOW MODERATE TO HIGH INSTABILITY  
TO DEVELOP, WITH HREF MEAN SUGGESTING 2000-3000 J/KG SBCAPE  
DEVELOPING BY EARLY AFTERNOON. FORECAST SOUNDINGS DEPICT LITTLE  
TO NO CAP WITH DIURNAL MIXING ALLOWING THE CONVECTIVE  
TEMPERATURE TO BE REACHED. FORCING FOR ASCENT IN THE PREFRONTAL  
AIRMASS IS WEAK, BUT IT MAY NOT TAKE MUCH TO INITIATE  
CONVECTION. WEAK MIDLEVEL FORCING FOR ASCENT MAY OCCUR IN THE  
FORM OF WEAK, LOW-AMPLITUDE CONVECTIVELY GENERATED DISTURBANCES  
FROM UPSTREAM, AND SURFACE TRIGGERS MAY BE PRESENT IN THE FORM  
OF A PREFRONTAL TROUGH AND UPSLOPE/TERRAIN CIRCULATIONS. TREND  
IN THE HREF MEMBERS HAS BEEN TO DEVELOP SCATTERED CLUSTERS OF  
THUNDERSTORMS IN THE 18-22Z TIMEFRAME, TARGETING THE I-90  
CORRIDOR AND POINTS SOUTH. WILL INCREASE POPS IN THIS AREA BUT  
CAP IT AT CHANCE GIVEN THE UNCERTAINTIES WITH RESPECT TO  
COVERAGE. HREF INDICATES LOWER POTENTIAL FOR AFTERNOON  
CONVECTION NORTH OF I-90 DURING THE AFTERNOON, BUT THE CHANCE IS  
NONZERO, SO HAVE FAIRLY UNIFORM CHANCE POPS THROUGHOUT THE AREA.  
DEEP-LAYER SHEAR IS FAIRLY WEAK AT 20-30 KT WITH MAINLY  
UNIDIRECTIONAL SHEAR, SO LONGEVITY OF CELLS IS IN QUESTION, AND  
STORM MODE IS EXPECTED TO BE MULTICELLULAR. BUT GIVEN THE  
INSTABILITY IN PLACE AND MIDLEVEL DRY AIR, THESE STORMS COULD  
CONTAIN BORDERLINE SEVERE WINDS. HAIL AND TORNADOES ARE NOT  
LIKELY GIVEN THE WARM, MOIST AIRMASS AND RELATIVELY  
UNIDIRECTIONAL SHEAR, RESPECTIVELY, BUT THEY CANNOT BE TOTALLY  
RULED OUT.  
 
POPS INCREASE FROM NORTH TO SOUTH 22-04Z AS LARGE-SCALE FORCING  
INCREASES IN ADVANCE OF THE FRONT. DEEP-LAYER SHEAR INCREASES SO  
COULD SEE SOME MORE ORGANIZED CONVECTION WITH ISOLATED TO  
SCATTERED SEVERE WINDS POSSIBLE. SEVERE THREAT SHOULD DIMINISH  
WITH SUNSET AS INSTABILITY DIMINISHES. LOCALLY HEAVY  
RAINFALL/ISOLATED FLASH FLOODING IS POSSIBLE AS WELL. WINDS  
THROUGH A GOOD DEAL OF THE ATMOSPHERE ARE PARALLEL TO THE  
BOUNDARY, WHICH COULD PROMOTE TRAINING OF CELLS. PWAT VALUES  
INCREASE TO 2-2.5 INCHES, H85/H7 DEWPOINTS INCREASE TO IN EXCESS  
OF 15/5C, RESPECTIVELY, AND FREEZING LEVELS GET UP ABOVE 16000  
FT, ALL EXCELLENT PARAMETERS FOR HEAVY RAIN. THE MITIGATING  
FACTOR FOR FLASH FLOODING WILL BE FAST MOVEMENT OF THE SYSTEM.  
 
RAINFALL WILL TAPER OFF NORTH TO SOUTH IN THE WAKE OF THE  
FRONTAL PASSAGE 04-09Z, WITH MUCH DRIER AIR FILTERING IN AS  
DEWPOINTS FALL INTO THE MID-50S TO MID-60S.  
 

 
   
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
 
 
FOR THE SHORT TERM PERIOD, THE LOCAL FORECAST AREA WILL BE ON  
THE SOUTHERN PERIPHERY OF A LONGWAVE TROUGH CENTERED OVER  
EASTERN CANADA. WE'LL RETURN TO NEAR CLIMATOLOGICAL HIGHS  
TUESDAY IN THE POSTFRONTAL AIRMASS. DEEP MIXING, LOW DEWPOINTS,  
PLENTY OF SUNSHINE, AND A BIT BREEZY. HIGH PRESSURE BUILDS IN  
TUESDAY NIGHT, SETTING THE STAGE FOR SOME GOOD RADIATIONAL  
COOLING CONDITIONS. WENT CLOSER TO COOLER MOS GUIDANCE COMPARED  
WITH BLENDED GRIDS.  
 
SOME UNCERTAINTY WEDNESDAY/WEDNESDAY NIGHT AS THE TROUGH  
SHARPENS AND SOME GUIDANCE DEVELOPS A SURFACE WAVE ALONG THE  
STATIONARY BOUNDARY STRUNG OUT ACROSS THE MID-ATLANTIC AND OHIO  
VALLEY. LATEST ECMWF/GFS/GEFS MEAN DEVELOP THIS WAVE ENOUGH TO  
BRING IN RAIN SHOWERS TO PORTIONS OF THE EASTERN CATSKILLS/MID  
HUDSON VALLEY/NORTHWEST CT LATE WEDNESDAY INTO WEDNESDAY NIGHT.  
NAM MEANWHILE IS DRY. WILL INTRODUCE SLIGHT/LOW CHANCE POPS IN  
THESE ZONES STARTING WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT.  
ELSEWHERE, ANOTHER DRY AND SEASONABLE DAY IS EXPECTED WITH  
PARTIAL COVERAGE OF HIGH CLOUDS.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
GUIDANCE IS IN GOOD AGREEMENT A LONGWAVE TROUGH SHOULD BE MOVING OFF  
TO THE EAST WITH HEIGHTS RISING OVER THE NORTHEAST AS RIDGING BUILDS  
IN TO CLOSE OUT THE WORK WEEK. WHILE AT SURFACE, HIGH PRESSURE  
SLIDES ACROSS THE REGION. EXPECTING FAIR WEATHER WITH SEASONAL  
TEMPERATURES.  
 
A CLOSED OFF UPPER LEVEL LOW OVER THE PLAINS WILL BE MOVING EASTWARD  
INTO THE RIDGE AS WE HEAD INTO THE WEEKEND. THIS LOW IS EXPECTED TO  
OPEN AND DEAMPLIFY AS ITS ADVANCED FARTHER EASTWARD BY A SHORTWAVE  
MOVING OVER THE ROCKIES. IT'S ALSO EXPECTED TO BE DRAWN  
NORTHEASTWARD AS SHORTWAVE ENERGY ROTATES ABOUT A LOW OVER HUDSON'S  
BAY CANADA. THE RESULT IS A LOW PRESSURE SYSTEM MOVING ACROSS THE  
REGION OVER THE WEEKEND BRINGING SOME RAINFALL TO THE LOCAL AREA  
AFTER ANOTHER STRETCH OF FAIR WEATHER. SEASONAL TEMPERATURES ARE  
EXPECTED TO CONTINUE JUST WITH MORE HUMID CONDITIONS AS THE LOW  
PRESSURE SYSTEM APPROACHES AND MOVES THROUGH.  
 

 
   
AVIATION /15Z MONDAY THROUGH FRIDAY/
 
 
A COLD FRONT IS ON THE APPROACH FROM THE NORTHWEST. IT'S  
EXPECTED TO MOVE ACROSS THE LOCAL AREA THIS EVENING. A PRE-  
FRONTAL TROUGH IS EXPECTED TO DEVELOP IN THE HOT AND HUMID  
AIRMASS AHEAD OF THE COLD FRONT. GUIDANCE INDICATES THAT  
SCATTERED CONVECTION SHOULD DEVELOP IN ASSOCIATION WITH THE  
PRE-FRONTAL TROUGH AND HAVE ADDRESSED THIS WITH A PROB30 GROUP  
IN TAFS. THE BETTER CHANCES FOR CONVECTION ARE EXPECTED WITH THE  
COLD FRONT. HAVE USED A TEMPO GROUP IN THE TAFS. STORMS WILL BE  
ASSOCIATED WITH MVFR-IFR CONDITIONS ALONG WITH GUSTY WINDS AND  
VERY HEAVY RAINFALL POSSIBLE. OTHERWISE VFR CONDITIONS ARE  
EXPECTED WITH CLOUD COVER ON THE INCREASE DURING THE DAY.  
 
SOUTH-SOUTHWEST WINDS WILL INCREASE IN SPEED AND BECOME GUSTY  
WITH GUSTS INTO THE 20S. STRONGER WIND GUSTS ARE EXPECTED IN  
ASSOCIATION WITH THUNDERSTORMS. WINDS WILL SHIFT MORE TO THE  
WEST THIS EVENING AS THE FRONT GETS CLOSER AND THE NORTHWEST  
WITH ITS PASSAGE.  
 
OUTLOOK...  
 
TUESDAY: LOW OPERATIONAL IMPACT. BREEZY NO SIG WX.  
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.  
 

 
   
FIRE WEATHER
 
 
HOT AND HUMID TODAY WITH RH VALUES ONLY FALLING TO THE 45 TO 70  
PERCENT RANGE. BECOMING BREEZY AS WELL WITH SOUTHWEST WINDS  
GUSTING UP TO 30 MPH. SCATTERED SHOWERS AND THUNDERSTORMS ARE  
POSSIBLE THIS AFTERNOON, BECOMING LIKELY THIS EVENING INTO  
TONIGHT. A DRIER AND MORE SEASONABLE AIRMASS TAKES HOLD TUESDAY,  
WITH RH VALUES FALLING INTO THE 35 TO 45 PERCENT RANGE. NORTH-  
NORTHWESTERLY WINDS MAY GUST TO NEAR 20 MPH. SIMILAR  
TEMPERATURES AND HUMIDITY WEDNESDAY BUT WITH LIGHTER WINDS.  
 

 
   
HYDROLOGY
 
 
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL BECOME  
MORE WIDESPREAD THIS EVENING AND TONIGHT AS A COLD FRONT  
INTERACTS WITH A HOT AND HUMID AIRMASS. THERE IS COPIOUS  
MOISTURE TO WORK WITH AND POTENTIAL FOR BACKBUILDING STORMS WITH  
WINDS PARALLEL TO THE FRONTAL BOUNDARY. PRECIPITABLE WATER  
VALUES ARE FORECAST TO BE 2-2.25 INCHES, WHICH IS NEAR THE  
CLIMATOLOGICAL DAILY MAXIMUM. SO STORMS ARE CERTAINLY CAPABLE OF  
HEAVY RAINFALL, WITH A THREAT FOR URBAN AND SMALL STREAM  
FLOODING AS WELL AS ISOLATED FLASH FLOODING. THE MITIGATING  
FACTOR WILL BE THE FAST MOVEMENT OF THE SYSTEM. WHILE BASIN  
AVERAGE AMOUNTS ARE EXPECTED TO RANGE BETWEEN 0.50 AND 1.00  
INCHES, LOCALLY HIGHER AMOUNTS ARE LIKELY.  
 
DRIER WEATHER RETURNS FOR THE REMAINDER OF THE WEEK.  
 
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.  
 

 
   
CLIMATE
 
 
RECORD HIGHS FOR TODAY...  
 
ALBANY NY - 97 DEGREES 1957 (RECORDS DATE BACK TO 1874)  
GLENS FALLS NY - 93 DEGREES 1994 (RECORDS DATE BACK TO 1949)  
POUGHKEEPSIE NY - 93 DEGREES 1957 (RECORDS DATE BACK TO 1931)  
 

 
   
ALY WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ038>041-043-  
048>050-052>054-059>061-063>066-083-084.  
MA...NONE.  
VT...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR VTZ015.  
 

 
 

 
SYNOPSIS...THOMPSON  
NEAR TERM...THOMPSON/JVM  
SHORT TERM...THOMPSON  
LONG TERM...IAA  
AVIATION...IAA/KL  
FIRE WEATHER...THOMPSON  
HYDROLOGY...THOMPSON  
CLIMATE...  
 
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