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Area Forecast Discussion
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000
FXUS61 KBUF 021209
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
809 AM EDT TUE SEP 2 2014

.SYNOPSIS...
A FEW SCATTERED LIGHT SHOWERS WILL CONTINUE ACROSS WESTERN NEW YORK 
THROUGH MID MORNING BEFORE A COLD FRONT SLOWLY CROSSES THE REGION 
THIS AFTERNOON THROUGH THIS 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/...
REGIONAL RADARS AT 12Z THIS MORNING SHOWING JUST A FEW LIGHT SHOWERS 
MOVING ACROSS THE NORTHERN FINGER LAKES...WITH QUIET CONDITIONS 
ELSEWHERE. THESE WILL CONTINUE TO WANE THROUGH MID MORNING. AFTER 
THAT...EXPECT THE AREA WILL REMAIN MAINLY DRY OUTSIDE OF THE 
POSSIBILITY OF A FEW POP UP LIGHT SHOWERS LATER THIS MORNING.  

THE AXIS OF BROAD MID AND UPPER LEVEL TROUGHING WILL SLIDE EAST 
FROM THE UPPER GREAT LAKES TO THE LOWER LAKES REGION TODAY WITH AN 
ASSOCIATED WEAK COLD FRONT EASING EASTWARD ACROSS THE FORECAST AREA 
FROM LATE THIS MORNING THROUGH THIS EVENING. EXPECT PRECIPITATION TO 
MOVE INTO WESTERN NEW YORK LATER THIS MORNING ON THE NOSE OF 30-35KT 
850MB JET...THEN REACHING NORTHCENTRAL NEW YORK BY EARLY TO MID 
AFTERNOON. SHOWERS AND STORMS WILL TAPER OFF FROM WEST TO EAST 
THROUGH THIS EVENING. THUNDERSTORM POTENTIAL REMAINS HIGH WITH 
FORECAST SBCAPES GENERALLY RUNNING BETWEEN 1000-1500 J/KG COMBINED 
WITH LIFTED INDEX VALUES AROUND -2C TO -3C. 0-6KM BULK SHEAR HAS 
ALSO INCREASED TO 40-45KT ACROSS MOST OF THE REGION JUST AHEAD OF 
THE FRONT...MAKING THE CHANCES OF A FEW STORMS REACHING SEVERE 
LIMITS EVEN BETTER. IN ADDITION...WILL HAVE INCREASING UPPER LEVEL 
DIFFLUENCE IN THE RIGHT ENTRANCE REGION OF A 110+ KNOT UPPER LEVEL 
JET NEARING THE REGION. KEY FACTOR STILL APPEARS TO BE THE AMOUNT OF 
SURFACE HEATING THAT TAKES PLACE BEFORE FROPA...I.E. WILL CLOUD 
COVER MOVE IN TOO EARLY AND LIMIT HEATING...AND THUS THE AMOUNT OF 
INSTABILITY. BETTER SURFACE HEAT LOOKS MORE LIKELY NOW AS THE FRONT 
APPEARS TO BE MOVING A BIT SLOWER TAKING A LOOK AT THE LATEST 
GUIDANCE PACKAGE...INCLUDING THE 06Z NAM. AREAS FROM THE SOUTHERN 
TIER NORTHEAST THROUGH THE FINGER LAKES REGION AND NORTH COUNTRY 
HAVE THE BEST SHOT AT SEEING THE MOST SUNSHINE OUT AHEAD OF THE 
FRONT...SO THESE LOOK TO BE THE MOST FAVORED AREAS FOR STRONGER 
STORMS. THESE AREAS ARE ALSO OUTLINED BY A SLIGHT RISK (15%) AREA 
FROM SPC...WITH THE REMAINDER OF THE AREA UNDER A 5% RISK. TO 
ADD...HIGH PRECIPITABLE WATER VALUES OF 1.7"-1.8" OUT AHEAD OF THE 
BOUNDARY OFFERS THE RISK FOR HEAVY DOWNPOURS WITH ANY THUNDERSTORM. 
ALL THESE FACTORS TAKEN INTO CONSIDERATION...IT APPEARS THERE WILL 
BE SOME STRONG STORMS...WITH A FEW STORMS POSSIBLY REACHING SEVERE 
LIMITS. MAIN THREATS APPEAR TO BE GUSTY WINDS ASSOCIATED WITH ANY 
BOWING LINE SEGMENTS AND LOCALLY HEAVY RAINFALL. IT WILL BE ANOTHER 
WARM DAY WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S.

THE COLD FRONT WILL SLIDE SOUTH AND EAST OF THE FORECAST AREA 
TONIGHT...TAKING THE SHOWERS AND STORMS WITH IT. ALTHOUGH A FEW 
SHOWERS WILL STILL BE POSSIBLE DURING THE EVENING ACROSS EASTERN 
AREAS...BUT EVEN HERE THINGS WILL DRY OUT LATER TUESDAY NIGHT AS 
SURFACE HIGH PRESSURE LOCATED ACROSS THE OHIO VALLEY STARTS TO BUILD 
EAST ACROSS THE REGION. 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 /12Z TUESDAY THROUGH SATURDAY/...
MVFR CIGS HAVE FORMED ACROSS KBUF AND KART...WITH INTERMITTENT MVFR 
CIGS AT KROC. IFR CIGS HAVE FORMED AT KJHW AS EXPECTED. VERY MOIST 
LOW LEVELS ARE THE MAIN CONTRIBUTOR TO THE LOW CIGS. EXPECT ALL 
AREAS TO BECOME VFR MID TO LATE MORNING AS LOW CLOUDS MIX OUT WITH 
DIURNAL HEATING.

REGIONAL RADARS AT 12Z THIS MORNING SHOWING JUST A FEW LIGHT SHOWERS 
MOVING ACROSS THE NORTHERN FINGER LAKES...WITH QUIET CONDITIONS 
ELSEWHERE. THESE WILL CONTINUE TO WANE THROUGH MID MORNING. AFTER 
THAT...EXPECT THE AREA WILL REMAIN MAINLY DRY OUTSIDE OF THE 
POSSIBILITY OF A FEW POP UP LIGHT SHOWERS LATER THIS MORNING.

A COLD FRONT WILL SLOWLY EASE EASTWARD ACROSS THE REGION THROUGH THE 
COURSE OF THE DAY. COUPLED WITH INCREASING DAYTIME 
INSTABILITY...EXPECT MORE WIDESPREAD SHOWERS AND STORMS TO DEVELOP 
ALONG AND AHEAD OF THIS FRONT AS IT CROSSES THE AREA THIS AFTERNOON 
INTO THIS EVENING...WITH SOME OF THESE POTENTIALLY BRINGING BRIEF 
PERIODS OF MVFR/IFR. A FEW OF THESE STORMS COULD EVEN BECOME STRONG 
TO SEVERE ACROSS THE FORECAST AREA. 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. IN ADVANCE OF THE FRONT...SOUTHWESTERLY WINDS WILL INCREASE 
THIS MORNING...PARTICULARLY ON LAKE ERIE WHERE WINDS AND WAVES WILL 
CLIMB TO NEAR ADVISORY LEVELS. IT APPEARS THAT WINDS WILL REMAIN AT 
OR JUST ABOVE ADVISORY CRITERIA THROUGH LATE AFTERNOON/EARLY 
EVENING...SO HAVE DECIDED TO EXTEND THE CURRENT SCA 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
NEAR TERM...JM
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...JM
MARINE...JM







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