062  
FXUS61 KBUF 021530  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
1130 AM EDT TUE SEP 2 2014  
   
SYNOPSIS
 
 
A COLD FRONT WILL SLOWLY CROSS THE REGION THIS AFTERNOON AND EVENING  
WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS...SOME OF WHICH COULD  
PRODUCE STRONG GUSTY WINDS AND HEAVY RAINFALL. IN THE WAKE OF THE  
FRONT...HIGH PRESSURE WILL BUILD INTO THE LOWER GREAT LAKES AND  
BRING A RETURN TO DRIER AND LESS HUMID WEATHER WEDNESDAY AND  
THURSDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
THE AXIS OF A BROAD MID LEVEL TROUGH WILL SHIFT EAST ACROSS THE  
GREAT LAKES TODAY WITH AN ASSOCIATED WEAK SURFACE COLD FRONT EASING  
EASTWARD ACROSS WESTERN AND CENTRAL NEW YORK THIS AFTERNOON AND  
EVENING. SOME LEADING PRE-FRONTAL SHOWERS ASSOCIATED WITH THE RIGHT  
ENTRANCE REGION OF THE UPPER LEVEL JET STREAM ARE CROSSING LAKE ERIE  
AND SOUTHWEST ONTARIO AT 15Z. SOME ISOLATED SHOWERS ARE ALSO BEING  
FORCED AHEAD OF THIS ACROSS WESTERN NEW YORK. EXPECT THIS FIRST  
BATCH OF SHOWERS JUST TO THE WEST TO MOVE INTO WESTERN NEW YORK LATE  
THIS MORNING AND EARLY AFTERNOON REACHING NORTH-CENTRAL NEW YORK BY  
EARLY TO MID AFTERNOON.  
 
REGIONAL RADARS SHOWING A A SECOND LINE OF SHOWERS ORIENTED ALONG  
THE SURFACE COLD FRONT CROSSING DETROIT TOWARD THE WESTERN END OF  
LAKE ERIE. THIS WILL BE THE FOCUS FOR STRONGER SHOWERS AND STORMS  
THIS AFTERNOON AND EVENING. THUNDERSTORM POTENTIAL REMAINS HIGH WITH  
FORECAST SBCAPES GENERALLY RUNNING BETWEEN 1000-1500 J/KG COMBINED  
WITH 0-6KM BULK SHEAR WHICH WILL INCREASE TO 40-50KT JUST AHEAD OF  
THE FRONT. IN ADDITION...WILL HAVE INCREASING UPPER LEVEL DIFFLUENCE  
IN THE RIGHT ENTRANCE REGION OF A 100+ KNOT UPPER LEVEL JET NEARING  
THE REGION. THE KEY FACTOR IN SEVERE THREAT STILL APPEARS TO BE THE  
AMOUNT OF SURFACE HEATING THAT TAKES PLACE BEFORE FROPA...I.E. CLOUD  
COVER LIMITING HEATING...AND THUS LIMITING THE AMOUNT OF INSTABILITY.  
 
A SLIGHT RISK OF SEVERE STORMS IS OUTLINED FROM SPC EXTENDING FROM  
THE INTERIOR SOUTHERN TIER ACROSS THE FINGER LAKES INTO CENTRAL NEW  
YORK. ELEVATED SHEAR AND LIMITED LAPSE RATES WILL KEEP STRONG GUSTY  
WINDS THE MAIN SEVERE THREAT. HIGH PRECIPITABLE WATER VALUES OF  
1.7"-1.8" OUT AHEAD OF THE FRONT WILL OFFER THE RISK FOR HEAVY  
DOWNPOURS WITH ANY THUNDERSTORM. TEMPERATURES AND HUMIDITY WILL  
REMAIN ON THE WARM AND MUGGY SIDE AGAIN TODAY WITH HIGHS MAINLY IN  
THE UPPER 70S TO LOWER 80S AND DEWPOINTS IN THE UPPER 60S TO LOW 70S.  
 
THE COLD FRONT WILL SLIDE EAST OF THE FORECAST AREA TONIGHT...TAKING  
THE SHOWERS AND STORMS WITH IT. HIGH PRESSURE BEHIND THE FRONT WILL  
BUILD EAST ACROSS NEW YORK BEHIND THE FRONT WITH DRYING AND CLEARING  
DEVELOPING OVERNIGHT. LOWS WILL BE GENERALLY IN THE UPPER 50S TO  
LOWER 60S.  
 

 
   
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
 
 
BY WEDNESDAY MORNING THE MID LEVEL TROUGH WILL HAVE LIFTED INTO  
EASTERN QUEBEC WITH SURFACE HIGH PRESSURE BUILDING INTO THE OHIO  
VALLEY. THIS WILL BRING A RETURN TO DRY WEATHER ON WEDNESDAY WITH  
DRYING AND SUBSIDENCE ON THE INCREASE. THERE MAY BE SOME LINGERING  
LOW LEVEL MOISTURE AND CLOUDS ACROSS THE HIGHER TERRAIN DURING THE  
MORNING. DIURNAL CUMULUS FIELDS MAY ALSO DEVELOP ACROSS THE HIGHER  
TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES...AND ALSO ALONG A  
CONVERGENCE ZONE RUNNING FROM THE NIAGARA PENINSULA TO NEAR  
ROCHESTER. THIS MAY YIELD A MIX OF CLOUDS AND SUN IN THESE AREAS FOR  
THE AFTERNOON. 850MB TEMPS OF AROUND +12C WILL SUPPORT HIGHS AROUND  
80 AT THE LOWER ELEVATIONS OF WESTERN NY WITH MID TO UPPER 70S  
ACROSS HIGHER TERRAIN AND THE NORTH COUNTRY.  
 
HIGH PRESSURE WILL BUILD NORTHEAST INTO NEW ENGLAND WEDNESDAY NIGHT  
AND THURSDAY WITH RIDGING EXTENDING BACK INTO THE LOWER LAKES. THIS  
WILL PROVIDE MORE DRY WEATHER WITH MAINLY CLEAR SKIES MUCH OF THE  
TIME. EXPECT DECENT RADIATIONAL COOLING CONDITIONS WEDNESDAY NIGHT  
ALTHOUGH THE AIRMASS IS NOT PARTICULARLY COOL OR DRY. LOWS WILL  
RANGE FROM AROUND 60 ON THE LAKE PLAINS TO AROUND 50 IN THE COOLEST  
SOUTHERN TIER VALLEYS AND TUG HILL REGION.  
 
WARM ADVECTION WILL INCREASE DURING THE DAY THURSDAY. ISENTROPIC  
UPGLIDE AND INCREASING MOISTURE MAY PRODUCE SOME PATCHY MID LEVEL  
CLOUDS...BUT THE THICKER CLOUD COVER SHOULD REMAIN ON THE CANADIAN  
SIDE OF THE INTERNATIONAL BORDER. 850MB TEMPS RISE TO +14C TO +16C  
BY THURSDAY AFTERNOON...SUPPORTING HIGHS IN THE MID 80S ACROSS LOWER  
ELEVATIONS.  
 
THURSDAY NIGHT WARM ADVECTION WILL INCREASE AS SOUTHWEST FLOW PICKS  
UP IN RESPONSE TO A STRONG COLD FRONT MOVING INTO THE WESTERN LAKES.  
ONGOING WARM ADVECTION AND ISENTROPIC UPGLIDE WILL BRING SOME  
INCREASE IN MID/HIGH CLOUDS. A WARMER AIRMASS AND A MIXING BREEZE  
OVERNIGHT WILL KEEP LOWS ON THE WARM SIDE WITH UPPER 60S ON THE LAKE  
PLAINS AND LOWER 60S IN THE SHELTERED SOUTHERN TIER VALLEYS AND TUG  
HILL REGION.  
 

 
   
LONG TERM /FRIDAY THROUGH MONDAY/
 
 
THE LONG TERM WILL BE VERY CHANGEABLE WITH ONE OF THE WARMEST DAYS  
OF THE YEAR ON FRIDAY FOLLOWED BY A SIGNIFICANT COOL DOWN FOR THE  
WEEKEND.  
 
ON FRIDAY A STRONG AND PROGRESSIVE MID LEVEL TROUGH WILL MOVE ACROSS  
NORTHWEST ONTARIO TO JAMES BAY. INCREASING SOUTHWEST FLOW AHEAD OF  
THIS FEATURE WILL CAPTURE AN ELEVATED MIXED LAYER /EML/ WITH ORIGINS  
ACROSS THE DESERT SOUTHWEST. THIS EML PLUME WILL ALLOW 850MB TEMPS  
TO SOAR TO AROUND +18C TO +19C. THIS WILL SUPPORT HIGHS IN THE UPPER  
80S TO LOWER 90S IN MANY AREAS...WITH THE WARMEST TEMPS LIKELY TO BE  
IN THE GENESEE VALLEY. THE EML PLUME WILL PROVIDE A STRONG CAP IN  
THE WARM SECTOR AND SHOULD HOLD CONVECTION AT BAY UNTIL AT LEAST  
LATE AFTERNOON WHEN THE UPSTREAM COLD FRONT AND TROUGH APPROACH AND  
AID IN ERODING THE MID LEVEL CAP.  
 
FRIDAY NIGHT COULD BE ACTIVE WITH A STRONG SURFACE COLD FRONT  
DROPPING SOUTHEAST ACROSS THE REGION. THE STRONGEST HEIGHT FALLS AND  
UPPER LEVEL SUPPORT WILL SHIFT EAST ACROSS QUEBEC...ALTHOUGH A  
TRAILING RIBBON OF STRONGER FLOW IN THE 900-700MB LAYER WILL PROVIDE  
ENOUGH CONVERGENCE TO ORGANIZE A BROKEN BAND OF CONVECTION ALONG THE  
FRONT. GIVEN THE STRENGTH OF THE FRONT AND BETTER AGREEMENT BETWEEN  
THE GFS AND ECMWF ON TIMING...HAVE BUMPED POPS TO LOW LIKELY FOR  
FRIDAY NIGHT.  
 
BY SATURDAY MODEL DIFFERENCES BEGIN TO SHOW...WITH THE ECMWF  
DEVELOPING A WEAK FRONTAL WAVE IN THE MID ATLANTIC. THIS WOULD HOLD  
UP THE FRONT SOMEWHAT AND ALSO FORCE IT TO BECOME MORE ANABATIC IN  
NATURE WITH SHOWERS LINGERING ON THE COOL SIDE OF THE BOUNDARY. THE  
GFS HAS A FASTER COLD FRONTAL PASSAGE WITH SATURDAY DRY. FOR NOW  
WILL HOLD ONTO LOW CHANCE POPS FOR SATURDAY WITH A HEDGE TO THE  
SLOWER ECMWF SOLUTION. IN EITHER CASE IT WILL BE NOTABLY COOLER  
SATURDAY...WITH HIGHS ONLY IN THE LOWER 70S IN MOST LOCATIONS.  
 
SATURDAY NIGHT THROUGH MONDAY THE FRONT WILL PUSH WELL SOUTHEAST OF  
THE REGION WITH HIGH PRESSURE BUILDING INTO THE GREAT LAKES. THIS  
WILL BRING A RETURN TO MAINLY DRY WEATHER. TEMPERATURES WILL REACH  
THEIR COOLEST ON SUNDAY WHEN HIGHS MAY NOT MAKE IT OUT OF THE UPPER  
60S AT LOWER ELEVATIONS AND MID 60S ACROSS HIGHER TERRAIN. AIRMASS  
MODERATION WILL BEGIN BY MONDAY WITH HIGHS BACK INTO THE LOWER 70S.  
 

 
   
AVIATION /16Z TUESDAY THROUGH SATURDAY/
 
 
MVFR/LOW VFR CIGS ARE ARRIVING ACROSS WESTERN AND CENTRAL NEW YORK  
AHEAD OF A COLD FRONT WHICH WILL CROSS THE REGION THIS EVENING.  
EXPECT THE LOWER CIGS TO LINGER INTO THE AFTERNOON WITH WIDESPREAD  
SHOWERS AND STORMS THEN DEVELOPING ALONG AND AHEAD OF THE FRONT THIS  
AFTERNOON AND EVENING. SOME OF THESE STORMS MAY BRING BRIEF PERIODS  
OF MVFR/IFR IN HEAVY DOWNPOURS. A FEW OF THESE STORMS COULD EVEN  
BECOME STRONG TO SEVERE ACROSS THE FORECAST AREA WITH STRONG GUSTY  
WINDS. OUTSIDE OF ANY SHOWERS AND THUNDERSTORMS...EXPECT VFR FLIGHT  
CONDITIONS.  
 
ALL OF THIS ACTIVITY WILL EXIT SOUTH AND EAST OF THE REGION THIS  
EVENING...WITH VFR FLIGHT CONDITIONS RETURNING FOR MOST OF THE  
NIGHT...WITH MVFR CEILINGS ONCE AGAIN POSSIBLE LATE IN THE TAF  
PERIOD ACROSS THE INTERIOR SOUTHERN TIER.  
 
OUTLOOK...  
WEDNESDAY AND THURSDAY...VFR.  
FRIDAY AND SATURDAY...A CHANCE OF SHOWERS AND THUNDERSTORMS WITH  
ASSOCIATED BRIEF MVFR/IFR...OTHERWISE VFR.  
 

 
   
MARINE
 
 
A COLD FRONT WILL CROSS THE LOWER LAKES REGION THIS AFTERNOON AND  
EVENING. ON LAKE ERIE WINDS AND WAVES WILL CLIMB TO NEAR ADVISORY  
LEVELS AND REMAIN AT OR JUST ABOVE ADVISORY CRITERIA THROUGH LATE  
AFTERNOON/EARLY EVENING...A SMALL CRAFT ADVISORY REMAINS IN EFFECT  
FOR LAKE ERIE THROUGH 00Z THIS EVENING. THE FRONT ITSELF WILL ALSO  
PRODUCE A ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS TODAY...OF  
WHICH A FEW COULD PRODUCE STRONG GUSTY WINDS AND LOCALLY HIGHER  
WAVES.  
 
IN THE WAKE OF THE FRONTAL PASSAGE...HIGH PRESSURE WILL BUILD ACROSS  
THE REGION TUESDAY NIGHT THROUGH THURSDAY WHILE BRINGING A RETURN TO  
FAIR WEATHER AND LIGHTER WINDS.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ040-  
041.  
 

 
 

 
 
SYNOPSIS...JM/SMITH  
NEAR TERM...JM/SMITH  
SHORT TERM...HITCHCOCK  
LONG TERM...HITCHCOCK  
AVIATION...JM/SMITH  
MARINE...JM/SMITH  
 
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