Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 220821
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
421 AM EDT TUE APR 22 2014

.SYNOPSIS...
A COLD FRONT WILL SWING ACROSS THE STATE TODAY...ACCOMPANIED WITH
LIGHT RAIN SHOWERS. AFTER A BRIEF LULL IN THE PRECIPITATION...AND
THEN AS COLDER AIR BUILDS IN BEHIND THE COLD FRONT TONIGHT A
SECONDARY BATCH OF LIGHT RAIN SHOWERS WILL MIX WITH SNOW TONIGHT AND
WEDNESDAY MORNING. TEMPERATURES WILL THEN GRADUALLY WARM THROUGH THE
END OF THE WEEK AS SURFACE HIGH PRESSURE BUILDS ACROSS THE REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS THIS EARLY MORNING DISPLAYS A CONSOLIDATING AND
DEEPENING AREA OF LOW PRESSURE OVER SOUTHEASTERN ONTARIO CANADA. A
COLD FRONT FROM THIS AREA OF LOW PRESSURE EXTENDS SOUTHWESTWARD BACK
THROUGH THE OHIO VALLEY AND INTO THE TENNESSEE VALLEY. WATER VAPOR
IMAGERY SHOWS A SHORTWAVE NOW REACHING NEAR LAKE MICHIGAN...AND A
SECOND SHORTWAVE NEAR LAKE WINNIPEG DIVING INTO THE UPPER LEVEL
TROUGH OF LOW PRESSURE. REGIONAL RADARS DISPLAY NUMEROUS LIGHT RAIN
SHOWERS AHEAD OF THE COLD FRONT...WITH ACTIVITY NOW REACHING FAR
WESTERN NEW YORK.

FOR TODAY LOW PRESSURE WILL CROSS LAKE ONTARIO AND NORTHERN NEW YORK
WHILE SWINGING A COLD FRONT ACROSS WESTERN NEW YORK THROUGH THE
MORNING HOURS...AND EARLY AFTERNOON ACROSS CENTRAL NEW YORK. WILL
CONTINUE WITH THE CATEGORICAL POPS TODAY FOR LIGHT RAIN SHOWERS
ALONG AND AHEAD OF THE COLD FRONT. OBSERVATIONS UPSTREAM SHOW MANY
OF THESE SHOWERS ARE LIGHT...AND THESE SHOWERS SHOULD NOT INCREASE
IN INTENSITY AS THEY CONTINUE TO PRESS INTO A DRIER AIRMASS. EXPECT
RAINFALL TODAY TO AVERAGE AROUND A TENTH OF AN INCH...AND UP TO TWO
TENTHS IN ANY HEAVIER ACTIVITY.

INSTABILITY REMAINS MINIMAL...THOUGH SOME SFC CAPE AND ELEVATED
INSTABILITY WILL REACH ACROSS THE ALLEGANY PLATEAU AND BRISTOL HILLS
TODAY AND WILL INSERT A SLIGHT CHANCE FOR THUNDER HERE.

WATER VAPOR IMAGERY SHOWS A DEVELOPING DRY SLOT NOW OVER THE WESTERN
GREAT LAKES. THIS DRY SLOT WILL REACH WNY THIS AFTERNOON AND ALLOW
FOR A BRIEF OPPORTUNITY FOR SOME LIMITED SUNSHINE. AS UPSTREAM
SHORTWAVES DEEPEN THE UPPER LEVEL TROUGH AND A SECONDARY SURFACE
TROUGH DROPS ACROSS THE REGION TONIGHT EXPECT ANOTHER PERIOD OF
LIGHT PRECIPITATION TO DEVELOP. MOISTURE WRAPPING AROUND THIS
SURFACE LOW WILL BE PLENTIFUL. THIS INCREASE IN MOISTURE WILL BRING
LIGHT SHOWERS AND DRIZZLE ACROSS LOWER ELEVATIONS TONIGHT...BUT
ACROSS HIGHER TERRAIN AS THE COLD AIR DEEPENS...850 HPA TEMPS
DROPPING DOWN TO -3 TO -5C...A CHANGE OVER TO SOME WET SNOW IS
POSSIBLE. WILL HAVE HIGHEST POPS TONIGHT OVER THE HIGHER TERRAIN
WITH AN UPSLOPE FLOW. GREATEST CHANCES FOR SOME SNOW WILL ALSO BE
ACROSS HIGHER TERRAIN WHERE A SLUSHY HALF INCH OR SO OF SNOW IS
POSSIBLE BY DAYBREAK.

TEMPERATURES ARE MILD THIS MORNING AHEAD OF THE COLD
FRONT...BUT EXPECT THESE TEMPERATURES TO SLOWLY DROP THROUGH THE
AFTERNOON AS THE COLD AIR FILTERS ACROSS THE REGION. TEMPERATURES
TONIGHT WILL BE MUCH COLDER THAN THIS MORNING WITH OVERNIGHT LOWS
DROPPING BACK INTO THE LOW TO MID 30S TONIGHT.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
THE AREA WILL BE UNDER A MOIST CYCLONIC NORTHWEST FLOW AT THE START
OF THE PERIOD WITH THE BETTER CHANCES FOR PRECIPITATION LIKELY TIED
TO THE HIGHER TERRAIN...WHERE UPSLOPE FLOW WILL HELP TO SQUEEZE OUT
ADDITIONAL MOISTURE. WE MAY ALSO SEE A BIT OF MOISTURE FLUX OFF OF
THE LAKES...ALTHOUGH TEMPERATURES ARE NOT COLD ENOUGH FOR TRUE LAKE
EFFECT PROCESSES. DEEPER MOISTURE WILL GRADUALLY PULL AWAY FROM THE
AREA DURING THE DAY. HOWEVER...THE REMAINING CYCLONIC FLOW AND COLD
AIR ALOFT WILL LIKELY CAUSE CLOUDS TO HANG AROUND FOR MUCH OF THE
DAY. DURING THE MID AND LATE AFTERNOON...THE LAKES WILL BECOME A
STABILIZING INFLUENCE... RESULTING IN CLOUDS CLEARING OUT OVER THE
LAKES AND LAKESHORE AREAS FIRST. THEN...THE CLEARING WILL SPREAD
INLAND. IT WILL BE ESPECIALLY CHILLY FOR THIS TIME OF YEAR WITH
HIGHS BARELY REACHING 50. THE COOL TEMPERATURES WILL ALSO BE
ACCOMPANIED BY A BRISK NORTHWEST FLOW WITH GUSTS IN THE 25-35 MPH
RANGE.

HIGH PRESSURE BUILDING INTO THE GREAT LAKES REGION WILL LEAD TO A
DRY PERIOD FOR WEDNESDAY NIGHT AND THURSDAY. THERE MAY BE A FEW
LINGERING CLOUDS OVER THE INTERIOR HIGHER TERRAIN TO START THE
EVENING...BUT OTHERWISE EXPECT CLEAR SKIES WEDNESDAY NIGHT AND SUNNY
SKIES FOR THURSDAY.

THE COOL AIRMASS AND CLEARING SKIES WILL ALLOW FOR A COLD NIGHT
WEDNESDAY NIGHT...WITH LOWS IN THE UPPER 20S TO LOWER 30S ON THE
LAKE PLAINS AND LOWER TO MID 20S IN THE COOLER INTERIOR LOCATIONS.
THE LATE APRIL SUNSHINE SHOULD HELP WARM TEMPS BACK CLOSER TO NORMAL
FOR THURSDAY WITH BACK INTO THE MID 50S IN MANY AREAS.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
THE LONG TERM HAS THE POTENTIAL TO BE QUITE UNSETTLED WITH A BRIEF
WARM-UP AT THE END OF THE WEEK FOLLOWED BY WELL BELOW AVERAGE
TEMPERATURES NEXT WEEKEND.

LOOKING AT THE DETAILS...ON FRIDAY A MID LEVEL SHORTWAVE AND WARM
OCCLUSION AT THE SURFACE WILL SWING QUICKLY EAST ACROSS THE REGION
WITH A CHANCE OF A FEW SHOWERS. THE RAIN SHOULD BE BRIEF AT ANY
GIVEN LOCATION AND SHOULD BE MAINLY IN THE MORNING ACROSS WESTERN
NY. A WARMER AIRMASS WILL MAKE A BRIEF APPEARANCE INTO THE LOWER
LAKES REGION WITH MOST AREAS REACHING THE LOW TO MID 60S FOR HIGHS.

MODEL GUIDANCE QUICKLY DIVERGES WITH RESPECT TO THE SYNOPTIC SCALE
EVOLUTION OVER THE WEEKEND...ALTHOUGH BOTH THE GFS AND ECMWF AND
MOST ENSEMBLES SUPPORT A TURN TOWARDS MUCH COLDER TEMPERATURES. THE
ECMWF SWINGS A PROGRESSIVE MID LEVEL CUTOFF THROUGH ONTARIO AND
QUEBEC OVER THE WEEKEND BEFORE REACHING THE CANADIAN MARITIMES ON
MONDAY...WITH A TROUGH DELIVERING A MUCH COOLER AIRMASS INTO THE
GREAT LAKES AND NORTHEAST. THE CUTOFF LOW IN THIS SCENARIO WOULD BE
FAR ENOUGH NORTH AND EAST TO KEEP OUR REGION MAINLY DRY.

THE GFS ON THE OTHER HAND RETROGRADES THE CLOSED LOW ON SUNDAY AND
MONDAY...KEEPING IT OVER OR JUST EAST OF NEW ENGLAND. THIS WOULD BE
CLOSE ENOUGH TO KEEP MORE WRAP AROUND MOISTURE AND PRECIP CHANCES
ACROSS OUR REGION...AND WITH THE COLDER AIR SOME OF THIS MAY BE IN
THE FORM OF WET SNOW...ESPECIALLY DURING THE LATE NIGHT AND EARLY
MORNING HOURS. GIVEN THE MODEL DISAGREEMENT...HAVE KEPT CHANCE POPS
THROUGH THE WEEKEND AND INTO MONDAY WITH SOME MIX OF SNOW AT TIMES.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
AT 06Z VFR FLIGHT CONDITIONS WERE FOUND ACROSS THE REGION AND THESE
CONDITIONS ARE EXPECTED TO CONTINUE FOR ANOTHER 6 TO 9 HOURS. A COLD
FRONT AND ASSOCIATED SHOWERS TO THE WEST WILL CROSS THE REGION THIS
MORNING...MAINLY BETWEEN 12Z AND 18Z TO THE WEST...AND 15 TO 21Z
ACROSS THE EASTERN LAKE ONTARIO REGION. MVFR FLIGHT RESTRICTIONS
WILL BE FOUND WITHIN THESE SHOWERS...POSSIBLY LOWERING TO IFR ACROSS
THE SOUTHERN TIER.

A DRY SLOT BEHIND THE COLD FRONT WILL LIKELY BRING A RETURN TO VFR
FLIGHT CONDITIONS LATER THIS AFTERNOON AND EARLY EVENING. THIS WILL
BE BRIEF AS WRAP AROUND MOISTURE BEHIND THE MAIN AREA OF LOW
PRESSURE WILL LOWER CIGS BACK TO IFR/MVFR THROUGH TOMORROW NIGHT
WITH LIGHT SHOWERS...AND POSSIBLY SOME SNOW MIXING IN LATE ACROSS
HIGHER TERRAIN.

LIGHT SOUTHWESTERLY WINDS THIS MORNING WILL INCREASE IN SPEED
THROUGH THE DAYLIGHT HOURS...AND VEER AROUND TO WEST AND THEN
NORTHWESTERLY THIS AFTERNOON AND EVENING BEHIND THE COLD FRONT.

OUTLOOK...
EARLY WEDNESDAY...VFR/MVFR. A CHANCE OF RAIN SHOWERS OR SNOW SHOWERS
ACROSS HIGHER TERRAIN.
WEDNESDAY AFTERNOON THROUGH THURSDAY...VFR.
FRIDAY AND SATURDAY...VFR/MVFR. A CHANCE OF SHOWERS.

&&

.MARINE...
SOUTHWEST WINDS AHEAD OF THE COLD FRONT ARE INCREASING TO ABOUT 20
KNOTS THIS MORNING ALONG THE LAKE ERIE SHORELINE...AND WILL HOIST A
SMALL CRAFT ADVISORY HERE...AND CONTINUE IT INTO THE OVERNIGHT
HOURS. ELSEWHERE SCA WILL REMAIN ON LAKE ONTARIO AS WEST TO
NORTHWEST WINDS AND WAVES AREA EXPECTED TO INCREASE BEHIND A COLD
FRONT TODAY.

TONIGHT WINDS WILL CONTINUE TO VEER...POSSIBLY TO NORTHWEST TO
NORTHERLY OVER THE WESTERN END OF LAKE ONTARIO. THIS MAY NECESSITATE
A SCA FOR THE LOWER NIAGARA RIVER LATER TONIGHT.

HIGH PRESSURE WILL THEN BUILD ACROSS THE LAKES WEDNESDAY AND
THURSDAY WITH A RETURN TO NON-SCA CONDITIONS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 11
         AM EDT THURSDAY FOR LOZ043-044.
         SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM EDT
         WEDNESDAY FOR LOZ042.
         SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT
         THURSDAY FOR LOZ045.

&&

$$

SYNOPSIS...THOMAS
NEAR TERM...THOMAS
SHORT TERM...TMA
LONG TERM...HITCHCOCK/TMA
AVIATION...THOMAS
MARINE...THOMAS







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