270  
FXUS61 KBGM 190023  
AFDBGM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BINGHAMTON NY  
823 PM EDT WED JUL 18 2018  
   
SYNOPSIS
 
 
AN EXPANSIVE HIGH PRESSURE SYSTEM WILL KEEP DRY AND PLEASANT  
WEATHER OVER THE REGION THROUGH FRIDAY. SKIES WILL BE MOSTLY  
CLEAR, EXCEPT FOR PATCHY EARLY MORNING VALLEY FOG. TEMPERATURES  
WILL GRADUALLY WARM THROUGH THE WEEK.  
 

 
   
NEAR TERM /THROUGH THURSDAY NIGHT/
 
 
830 PM UPDATE... BASICALLY, NO CHANGE TO THE CURRENT FORECAST,  
WHICH IS IN EXCELLENT SHAPE.  
 
AS SPRAWLING HIGH PRESSURE BUILDS RIGHT ACROSS CNY/NEPA  
OVERNIGHT, CLEAR SKIES/LIGHT WINDS WILL LEAD TO GOOD RADIATING  
CONDITIONS, AND THE DEVELOPMENT OF VALLEY FOG IN THE TWIN  
TIERS. COOLER VALLEYS SHOULD DROP WELL DOWN INTO THE 40S PRIOR  
TO DAYBREAK. ALL OF THESE FACTORS ARE VERY WELL HANDLED IN THE  
CURRENT GRIDDED FORECAST.  
 
PREVIOUS DISCUSSION... 145 PM UPDATE... FORECAST IN GOOD SHAPE  
WITH JUST MINOR CHANGES.  
 
HIGH PRESSURE IS BUILDING IN TODAY WITH COOL DRY AIR. THE HIGH  
WILL BE OVER THE AREA THURSDAY MORNING. EARLY THIS AFTERNOON  
SOME LAKE EFFECT CLOUDS ARE ACROSS MOST OF THE AREA. 850MB TEMPS  
HAVE FALLEN TO +10C WHICH IS ENOUGH GIVEN THE WARM LAKE ONTARIO  
SURFACE TEMPERATURES. THESE CUMULUS WILL QUICKLY DISAPPEAR LATE  
AFTERNOON AS THE SURFACE HEATING WANES. MAINLY CLEAR SKIES WILL  
THEN BE THE RULE TONIGHT THROUGH THURSDAY NIGHT.  
 
TONIGHT WILL BE COOL WITH LOWS MOSTLY 45 TO 50. TEMPERATURES  
WILL FALL QUICKLY WITH LIGHT TO CALM WINDS, A DRY AIR MASS, AND  
CLEAR SKIES. WITH WARM RIVER TEMPERATURES, VALLEY FOG WILL FORM  
ACROSS SOUTH CENTRAL NY AND NEPA.  
 
WITH THE SURFACE HIGH SLOWLY MOVING EAST A RETURN FLOW OF WARM  
AIR FROM THE SOUTH WILL START. ALOFT THE TROUGH WILL MOVE IN AS  
A RIDGE MOVES THROUGH THE AREA THURSDAY NIGHT. HIGHS THURSDAY IN  
THE UPPER 70S AND LOWER 80S, FOLLOWED BY THURSDAY NIGHT LOWS IN  
THE 50S. WINDS ARE STILL LIGHT ENOUGH THURSDAY NIGHT THAT VALLEY  
FOG IS AGAIN LIKELY.  
 

 
   
SHORT TERM /FRIDAY THROUGH SATURDAY/
 
 
355 PM UPDATE...  
SURFACE HIGH PRESSURE WILL GRADUALLY MOVE EASTWARD AND MOVE OFF  
THE NEW ENGLAND COAST. MEANWHILE, AN UPPER LEVEL RIDGE WILL  
DEVELOP OVER THE REGION. THE COMBINATION OF THE TWO WILL ALLOW  
FOR SOUTHERLY FLOW FRIDAY WITH WARMER TEMPERATURES AND  
INCREASING DEWPOINTS, MAKING IT FEEL NOTICEABLY MORE HUMID.  
HIGHS WILL GENERALLY BE IN THE MID TO UPPER 80S.  
 
FRIDAY NIGHT: CLOUDS WILL SLOWLY INCREASE AS AN UPPER LEVEL LOW  
OVER THE CENTRAL GREAT LAKES AND AN ASSOCIATED UPPER LEVEL  
TROUGH OVER THE LOWER OHIO VALLEY WILL CONTINUE TO SLOWLY SPIN  
EASTWARD. DESPITE THE INCREASING CLOUDS, IT WILL REMAIN RAIN-  
FREE DURING THIS TIMEFRAME, AS THERE WILL BE VERY DRY AIR IN  
THE MID-LEVELS. LOWS WILL GENERALLY BE IN THE LOWER TO MID 60S,  
WITH MID TO UPPER 50S EXPECTED OVER THE CATSKILLS.  
 
SATURDAY: THE TREND OF GRADUAL INCREASING CLOUDS WILL CONTINUE  
THROUGHOUT THE DAY AS A CLOSED LOW DROPS INTO THE GREAT LAKES  
AND A COASTAL LOW DEVELOPS. WITH DRY AIR STILL BEING A FACTOR,  
IT APPEARS THAT IT WILL REMAIN RAIN-FREE ACROSS OUR AREA THROUGH  
THE EARLY PART OF THE AFTERNOON. INTRODUCED THE CHANCE FOR  
SHOWERS FOR THE LATE AFTERNOON, MAINLY ACROSS NEPA, AS THE  
NORTHWESTERN EDGE OF SOUTHERN STREAM LOW MOVE CLOSER TO THE  
AREA AND THE MID- LEVELS BEGIN TO MOISTEN UP. THERE IS STILL  
QUITE A BIT OF MODEL DISCREPANCY IN TERMS OF THE TIMING OF THE  
FIRST SHOWERS, SO THIS WILL HAVE TO BE MONITORED CLOSELY. HIGHS  
WILL GENERALLY BE IN THE LOWER 80S. THE EXCEPTION WILL BE ACROSS  
THE NORTHWESTERN PORTION OF OUR CWA, AS SURFACE WINDS FROM THE  
SOUTHEAST WILL ALLOW FOR DOWNSLOPING AND SLIGHTLY WARMER HIGHS  
(MID 80S).  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
355 PM UPDATE...  
COMPLICATED AND FAIRLY WET PATTERN DEVELOPS AS WE HEAD INTO NEXT  
WEEK. A CLOSED LOW IS STILL PROJECTED TO DROP INTO THE WESTERN  
GREAT LAKES BUT BEYOND THEN THINGS GET A LITTLE STRANGE. THE  
MODELS HAVE STRUGGLED WITH WHAT TO DO WITH IT ESPECIALLY IN  
TERMS OF RUN-TO-RUN CONSISTENCY, BUT ALL GENERALLY NOW HAVE A  
VERSION OF THE LOW RETROGRADING SOUTH OR EVEN SOUTHWEST. TO THE  
NORTH OF IT, THE LOOSE CONNECTION TO THE NORTHERN STREAM SHEARS  
OUT AS A TROUGH SOMEWHERE OVER THE CENTRAL GREAT LAKES WITH  
UNCERTAINTY AS TO HOW MUCH WE GET INTO THE BELT OF WESTERLIES,  
IF INDEED AT ALL. WHAT DOES APPEAR LIKELY, THOUGH, IS A MOIST  
TROUGHY PATTERN OVER OUR REGION WITH SEVERAL BOUTS OF SHOWERS  
AND A CHANCE OF THUNDERSTORMS DURING THE PERIOD DUE TO MOISTURE  
CONNECTIONS TO THE GULF AND ATLANTIC, AHEAD OF THE CUTOFF LOW  
AND TROUGH FEATURES. DAYTIME TEMPERATURES WILL NOT BE FAR FROM  
CLIMATOLOGY, BUT NIGHTS WILL TEND TO BE WARM AND MUGGY  
ESPECIALLY SUNDAY NIGHT ONWARD.  
 

 
   
AVIATION /01Z THURSDAY THROUGH MONDAY/
 
 
130 PM UPDATE...  
 
VFR THROUGH THE PERIOD OUTSIDE OF LATE NIGHT VALLEY FOG AT KELM.  
SKIES WILL BE SCATTERED TO BROKEN THIS AFTERNOON WITH HEIGHTS  
AROUND 6K FEET. TONIGHT AND THURSDAY WILL BE MAINLY CLEAR.  
 
VALLEY FOG IS LIKELY AFTER 06Z TONIGHT. THIS WILL AFFECT KELM  
WITH AT LEAST MVFR VSBYS 7 TO 13Z. TEMPO FOR VLIFR VSBYS AND  
CIGS NEAR FLIGHT MINIMUMS. LOW TEMPERATURES IN THE MID 40S THERE  
WILL EASILY FALL BELOW THE CROSSOVER TEMPERATURES. RIVER  
TEMPERATURES STILL IN THE 70S. WITH THE HIGH OVERHEAD LOW LEVEL  
WINDS WILL BE UNDER 10 KTS. FOR THE REST OF THE SITES NOT  
EXPECTING VALLEY FOG TO BE DEEP AND WIDESPREAD ENOUGH TO GET TO  
THEM.  
 
THIS AFTERNOON NORTH WINDS AT 10 KTS BECOMING LIGHT AND VARIABLE  
TO CALM TONIGHT, THEN CONTINUING INTO THURSDAY.  
 
OUTLOOK...  
 
THURSDAY NIGHT THROUGH SATURDAY...MAINLY VFR. RESTRICTIONS  
POSSIBLE DUE TO VALLEY FOG EACH MORNING, ESPECIALLY AT ELM.  
 
LATE SATURDAY THROUGH MONDAY...RESTRICTIONS LIKELY IN SHOWERS  
AND THUNDERSTORMS.  
 

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

 
 

 
SYNOPSIS...TAC  
NEAR TERM...MLJ/TAC  
SHORT TERM...BJG/MDP  
LONG TERM...MDP  
AVIATION...DJP  
 
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