821  
FXUS61 KBUF 211503  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
1103 AM EDT THU AUG 21 2014  
   
SYNOPSIS
 
 
AN UPPER LEVEL DISTURBANCE WILL BRING CONTINUED CHANCES FOR  
SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING...ESPECIALLY ACROSS  
THE EASTERN LAKE ONTARIO REGION WHERE A STATIONARY FRONT LIES. A FEW  
SHOWERS OR A THUNDERSTORM WILL LINGER INTO FRIDAY AND SATURDAY...BUT  
MUCH OF THE TIME WILL BE RAIN FREE WITH SEASONABLE TEMPERATURES. AN  
AREA OF HIGH PRESSURE WILL BRING DRY CONDITIONS ON SUNDAY WITH  
MOSTLY SUNNY SKIES.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
LATE THIS MORNING WATER VAPOR IMAGERY DISPLAYS A CLOSED UPPER LEVEL  
LOW NEAR LAKE HURON/GEORGIAN BAY. A WEAK SURFACE LOW IS REFLECTED AT  
THE SURFACE BETWEEN GEORGIAN BAY AND THE EASTERN GREAT LAKES. AN ILL  
DEFINED STATIONARY FRONT LIES ACROSS WESTERN AND NORTH CENTRAL NEW  
YORK.  
 
A MOISTURE RICH BOUNDARY LAYER...COMBINED WITH DAYTIME HEATING IS  
PRODUCING A THIN LAYER OF DIURNAL CUMULUS CLOUDS ACROSS WESTERN NEW  
YORK LATE THIS MORNING. EXPECT THESE TO LIFT SOME AND SCATTER OUT AS  
WE CONTINUE TO HEAT UP THIS AFTERNOON...WITH MORE CLOUDS HANGING ON  
INLAND FROM THE LAKES.  
 
REGIONAL RADARS SHOWING WHAT IS LEFT OF LINE OF SHOWERS MOVING EAST  
THROUGH THE EASTERN LAKE ONTARIO REGION LATE THIS MORNING. THIS  
ACTIVITY.  
 
FOR THE REST OF TODAY IN THE PRESENCE OF THE UPPER LEVEL LOW...AND  
BOUNDARY LAYER CONVERGENT CIRCULATION AROUND THE SURFACE LOW  
SCATTERED SHOWERS AND DAYTIME INSTABILITY THUNDERSTORMS WILL FORM.  
ACTIVITY WILL BE MOST PROMINENT ACROSS THE NORTHERN FINGER LAKES AND  
EASTERN LAKE ONTARIO REGION WHICH WILL LIE CLOSER TO THE WEAK  
STATIONARY FRONT AS WELL AS DEEPER MOISTURE. ACROSS WNY SCATTERED  
ACTIVITY WILL BE MOST LIKELY THROUGH THE AFTERNOON HOURS WHEN WEAK  
SURFACE INSTABILITY WILL BE GREATEST...ALTHOUGH MANY AREAS WEST OF  
THE FINGER LAKES REGION WILL LIKELY REMAIN RAIN FREE TODAY.  
 
LATER THIS AFTERNOON A WEDGE OF DRIER AIR IN THE 850-500 HPA LAYER  
WILL LIKELY DIMINISH ANY CONVECTIVE SHOWER CHANCES ACROSS FAR WNY.  
THEN AS THIS DRIER LAYER PUSHES EASTWARD IN COMBINATION WITH THE  
LOSS OF DAYTIME INSTABILITY AND WEAKENING OF THE UPPER LEVEL  
LOW...SHOWERS AND ANY REMAINING THUNDERSTORMS WILL END FROM WEST TO  
EAST THROUGH THE EARLY OVERNIGHT HOURS.  
 
AS THE SURFACE LOW WEAKENS TONIGHT OVER THE REGION AND SURFACE WINDS  
GO LIGHT AND VARIABLE...LINGERING LOW LEVEL MOISTURE WILL BRING  
PATCHY FOG ACROSS THE REGION. FOG AND LOW CLOUDS WILL LIKELY BE  
THICKEST ACROSS THE VALLEYS AND HILLS OF SW NYS.  
 
AIR TEMPERATURES WILL BE SEASONABLE TODAY WITH AFTERNOON  
TEMPERATURES SOUTH OF LAKE ONTARIO SIMILAR TO YESTERDAY...WITH  
HIGHS IN THE MID 70S TO AROUND 80. THE COOLEST 24-HR CHANGE TO THE  
AFTERNOON TEMPERATURES WILL BE ACROSS THE NORTH COUNTRY WHERE TODAY WILL  
START CLOUDY AS OPPOSED TO YESTERDAY WHEN SOME SUNSHINE STARTED THE  
DAY. TONIGHT LOWS WILL RANGE THROUGH THE LOW TO MID 60S WITH A  
CONTINUED MUGGINESS FEEL TO THE AIR...ESPECIALLY IN AREAS WHERE FOG  
FORMS.  
 

 
   
SHORT TERM /FRIDAY THROUGH SUNDAY/
 
 
THE PERIOD WILL START OFF WITH AN UPPER LEVEL TROUGH ACROSS NEW  
ENGLAND...BUT THIS WILL GRADUALLY BREAK DOWN AS AN UPPER LEVEL RIDGE  
DEVELOPS. THERE WILL BE MODEST INSTABILITY ON FRIDAY...NAM FORECAST  
SOUNDINGS SHOWING THIN AND NARROW CAPE OF AROUND 500 J/KG. IT IS  
DIFFICULT TO FIND ANY CLEARLY DEFINED SYNOPTIC TRIGGERS FOR  
CONVECTION...BUT THERE DOES APPEAR TO BE SUBTLE AREA WITH SURFACE  
CONVERGENCE EAST OF GENESEE VALLEY. NAM/SREF/RGEM/GFS CONSENSUS QPF  
ALSO KEYS ON THIS REGION...BUT EXPECT COVERAGE TO BE SPARSE  
SUPPORTING JUST CHANCE POPS. OTHERWISE...A DEVELOPING NE FLOW OFF  
LAKE ONTARIO MAY HELP SHADOW THE NIAGARA FRONTIER FRIDAY AFTERNOON.  
AREAL COVERAGE SHOULD DIMINISH WITH THE LOSS OF DAYTIME  
HEATING...BUT A FEW SHOWERS MAY LINGER THROUGH FRIDAY NIGHT.  
STRONGER CELLS WILL PROBABLY HAVE LIGHTNING...BUT THUNDERSTORMS  
SHOULD BE FAIRLY SPARSE IN COVERAGE.  
 
THE UPPER LEVEL RIDGE WILL BUILD INTO THE NORTH COUNTRY ON SATURDAY  
BEFORE SPREADING ACROSS THE ENTIRE REGION ON SUNDAY. THERE MAY BE A  
FEW DIURNAL SHOWERS SATURDAY...BUT THESE SHOULD END QUICKLY SATURDAY  
NIGHT WITH DRY WEATHER FOR THE REMAINDER OF THE WEEKEND.  
TEMPERATURES WILL BE RATHER SEASONABLE...WITH DAYTIME HIGHS  
AVERAGING IN THE MID TO UPPER 70S FRIDAY AND SATURDAY. SUNDAY SHOULD  
BE A TAD WARMER WITH A BIT MORE SUNSHINE ALLOWING A FEW SPOTS TO  
REACH 80 DEGREES.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
 
 
UPPER LEVEL RIDGING WILL SUPPORT SURFACE HIGH PRESSURE WHICH SHOULD  
INFLUENCE OUR WEATHER WELL INTO NEXT WEEK. THE RIDGE SHOULD START TO  
BREAK DOWN BY MID-WEEK...BUT EVEN AS IT DOES THERE IS ONLY A SMALL  
CHANCE OF SHOWERS THROUGH MID-WEEK. THIS SHOULD RESULT IN A NICE  
STRETCH OF WEATHER FOR OUR REGION...WITH MAINLY DRY WEATHER AND  
AMPLE SUNSHINE. MEANWHILE TEMPERATURES SHOULD BE A BIT ABOVE  
NORMAL...WITH HIGHS IN THE UPPER 70S TO LOWER 80S.  
 

 
   
AVIATION /15Z THURSDAY THROUGH MONDAY/
 
 
AT 15Z A COMBINATION OF MVFR/VFR FLIGHT CONDITIONS WERE FOUND ACROSS  
THE REGION. A MOISTURE RICH BOUNDARY LAYER...COMBINED WITH SOME  
DAYTIME HEATING IS ALREADY PRODUCING A THIN LAYER OF MAINLY MVFR  
CIGS ACROSS WESTERN NEW YORK LATE THIS MORNING. EXPECT THESE TO LIFT  
SOME AND SCATTER OUT AS WE CONTINUE TO HEAT UP THIS AFTERNOON...WITH  
MORE CLOUDS HANGING ON INLAND FROM THE LAKES.  
 
SCATTERED SHOWERS WILL THEN BE POSSIBLE THROUGH THIS AFTERNOON DUE  
TO PLENTY OF AVAILABLE LOW LEVEL MOISTURE IN COMBINATION WITH  
DAYTIME HEATING. A THUNDERSTORM WILL ALSO BE POSSIBLE ACROSS THE  
NORTH COUNTRY. WITH THE ACTIVITY BEING SCATTERED IN NATURE WILL  
CONTINUE WITH VCSH FOR ALL TAF SITES...WITH SHOWER ACTIVITY MOST  
LIKELY ACROSS THE NORTHERN FINGER LAKES REGION AND NORTH COUNTRY.  
 
MUCH OF THE PRECIPITATION WILL COME TO AN END OVER THE LAST 12 HOURS  
OF THE TAF CYCLE...WITH THE REGION BECOMING MOSTLY DRY THROUGH THE  
OVERNIGHT TIME PERIOD. AS WINDS GO LIGHT AND VARIABLE OVERNIGHT SOME  
PATCHY TO AREAS OF FOG ARE LIKELY WITH MVFR/IFR FLIGHT CONDITIONS  
DEVELOPING ACROSS ALL TAF SITES. THE EXTENT OF MVFR/IFR VISIBILITY  
VERSUS MVFR/IFR CIGS WILL BE DEPENDENT ON HOW MUCH CLEARING IS SEEN  
EARLIER IN THE OVERNIGHT.  
 
OUTLOOK...  
FRIDAY AND SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.  
SUNDAY AND MONDAY...MAINLY VFR.  
 

 
   
MARINE
 
 
BROAD LOW PRESSURE OVER LAKE HURON WILL DRIFT EASTWARD TOWARDS LAKE  
ONTARIO THIS AFTERNOON...AND THEN DISSIPATE TONIGHT OVER THE LOWER  
LAKES REGION. OCCASIONAL SHOWERS AND A FEW THUNDERSTORMS WILL BE  
POSSIBLE THROUGH THIS EVENING AS THIS LOW TRACKS  
EASTWARD...OTHERWISE A RELATIVELY FLAT PRESSURE GRADIENT WILL REMAIN  
IN PLACE AND PROMOTE MINIMAL WINDS AND WAVES RIGHT THROUGH THE END  
OF THE WEEK.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...NONE.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...JM/THOMAS  
NEAR TERM...JM/THOMAS  
SHORT TERM...APFFEL  
LONG TERM...APFFEL/RSH  
AVIATION...JM/THOMAS  
MARINE...JM/THOMAS  
 
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