318  
FXUS61 KBGM 211335  
AFDBGM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BINGHAMTON NY  
935 AM EDT MON AUG 21 2017  
   
SYNOPSIS
 
 
AN UPPER LEVEL DISTURBANCE WILL PRODUCE ISOLATED TO SCATTERED  
THUNDERSTORMS THIS AFTERNOON OVER NORTHEAST PENNSYLVANIA AND THE  
SOUTHERN TIER. A COLD FRONT WILL CROSS THE AREA TUESDAY  
AFTERNOON AND EVENING BRINGING SHOWERS AND THUNDERSTORMS, SOME  
OF WHICH WILL BE STRONG.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
930 AM UPDATE...MADE ADJUSTMENTS TO THE TIMING AND COVERAGE OF  
THE WEAKENING SHOWERS OVER THE CENTRAL SOUTHERNTIER. SHORT TERM  
MODELS SHOW THEM DRYING OUT AS THEY ADAVANCE TO NEAR THE I81  
CORRIDOR. LATER IN THE DAY, SOME CONVECTION POSSIBLE AS WELL,  
MAINLY OVER NEPA. ADJUSTED CLOUD COVER AS WELL, AS SOME AREAS  
MAY NOW HAVE TROUBLE SEEING THE ECLIPSE. PREVIOUS DISCUSSION  
CONTINUES BELOW.  
 
SURFACE HIGH PRESSURE OFF DELMARVA WILL GIVE THE REGION A  
SOUTHWEST FLOW OF WARM AIR AND INCREASINGLY HUMID AIR. A  
COMBINATION OF DIURNAL INSTABILITY AND A MID LEVEL SHORT WAVE IN  
ZONAL FLOW WILL PRODUCE ISOLATED TO SCATTERED THUNDERSTORMS  
OVER NORTHEAST PENNSYLVANIA AND THE SOUTHERN TIER FROM LATE THIS  
MORNING THROUGH THE AFTERNOON. SKIES WILL BE MOSTLY SUNNY  
ACROSS THE NORTHERN FORECAST AREA AND PARTLY SUNNY FROM THE  
SOUTHERN TIER SOUTH. VIEWING THE ECLIPSE ACROSS THE TWIN TIERS  
MAY BE CHALLENGING DUE TO CLOUD COVER AND CONVECTION. HIGHS WILL  
RANGE IN THE LOWER TO MIDDLE 80S.  
 
TONIGHT WILL BE DRY AFTER LINGERING CONVECTION DISSIPATES BY  
EARLY EVENING. CONDITIONS WILL BE MILD WITH LOWS RANGING FROM 65  
TO 70.  
 

 
   
SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/
 
 
SURFACE LOW PRESSURE WILL TRACK FROM THE WESTERN GREAT LAKES  
INTO SOUTHERN QUEBEC AND PUSH A STRONG COLD FRONT THROUGH THE  
AREA BETWEEN 21Z-03Z. CONDITIONS STILL LOOK FAVORABLE FOR SEVERE  
WEATHER AS MODELS INDICATE SURFACE BASED CAPE RANGING FROM  
1500-2500 J/KG, DEEP LAYER SHEAR OF 40-45 KNOTS, STRONG MID  
LEVEL FLOW, SIGNIFICANT LOW LEVEL HELICITY AND STRONG FRONTAL  
FORCING. THE ONLY LIMITING FACTOR CONTINUES TO BE THE MID LEVEL  
LAPSE RATES. FOR NOW WILL MENTION GUSTY WINDS AND HEAVY RAIN  
WITH THE THUNDERSTORMS DURING THE MID AFTERNOON AND EARLY  
EVENING PERIOD. WILL ADVERTISE CATEGORICAL TO LIKELY POPS WITH  
FRONTAL PASSAGE. THE POTENTIALLY SIGNIFICANT CONVECTION WILL  
MOVE THROUGH THE AREA BY LATE EVENING WITH MUCH OF THE ACTIVITY  
COMING TO AN END AFTER MIDNIGHT.  
 
HIGHS ON TUESDAY WILL RANGE IN THE MIDDLE TO UPPER 80S. LOWS  
TUESDAY NIGHT WILL RANGE IN THE 60S.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SUNDAY/
 
 
LATE THIS WEEK THROUGH THE WEEKEND WILL BE DOMINATED BY A  
LARGE-SCALE TROUGH ACROSS EASTERN NORTH AMERICA. THE RESULT WILL  
BE MOSTLY DRY CONDITIONS WITH TEMPERATURES BELOW NORMAL FOR LATE  
AUGUST. A WEAK SHORT WAVE MAY MOVE THROUGH THE AREA IN  
NORTHWEST FLOW ON THURSDAY BRINGING A SMALL CHANCE FOR SOME  
AFTERNOON SHOWERS MAINLY OVER UPSTATE NY AND HAVE RAISED POPS TO  
20 TO 30 PERCENT FOR THAT AREA LATE THURSDAY, OTHERWISE POPS  
WILL BE LOWER THAN 20 PERCENT. THE COOL DRY PATTERN APPEARS TO  
HOLD THROUGH THE WEEKEND AND MAY EVEN BE RE-INFORCED EARLY NEXT  
WEEK.  
 
320 PM EDT UPDATE... UPDATED FORECAST WITH NEW WPC GUIDANCE...  
 
HIGH PRESSURE IS EXPECTED TO MOVE INTO THE REGION AND  
IS EXPECTED TO REMAIN OVER THE AREA FOR THE REMAINDER OF THE  
FORECAST PERIOD. HIGH PRESSURE WILL RESULT IN DRY WEATHER BELOW  
SEASONAL TEMPS.  
 

 
   
AVIATION /14Z MONDAY THROUGH FRIDAY/
 
 
AT KELM, VALLEY FOG WITH CONDITIONS NEAR AIRPORT MINIMUMS WILL  
LIFT BY 13Z. A MID LEVEL SHORT WAVE WILL INCREASE CLOUD COVER  
LATE THIS MORNING THROUGH THE AFTERNOON ACROSS THE SOUTHERN  
TERMINALS WITH SCT/BKN CONDITIONS AROUND 5K FEET AT KRME/KSYR  
JUST SCATTERED CLOUDS. ISOLATED TO SCATTERED THUNDERSTORMS ARE  
ALSO POSSIBLE BUT NOT INCLUDED IN TAF DUE TO LIMITED AREAL  
COVERAGE. OVERNIGHT, JUST SOME MID/HIGH LEVEL CLOUDS WITH MVFR  
CONDITIONS IN FOG POSSIBLE PRIMARILY IN THE SOUTHERN TERMINALS  
AFTER 09Z.  
 
LIGHT AND VARIABLE WINDS BECOMING SOUTHWEST 5-10 KNOTS THEN  
LIGHT AND VARIABLE AGAIN OVERNIGHT.  
 
OUTLOOK...  
 
TUESDAY...RESTRICTIONS LIKELY IN SHOWERS AND THUNDERSTORMS.  
 
WEDNESDAY/THURSDAY/FRIDAY...VFR.  
 

 
   
BGM WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NY...NONE.  
 

 
 

 
SYNOPSIS...DGM/RRM  
NEAR TERM...DGM/RRM  
SHORT TERM...RRM  
LONG TERM...MSE  
AVIATION...RRM  
 
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