FXUS61 KBUF 110840
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
340 AM EST SAT FEB 11 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY AND USHER IN MUCH COLDER
AIR ALONG WITH SOME SNOW...WHICH WILL BE MOST PERSISTENT ACROSS
WESTERN NEW YORK. ANOTHER PERIOD OF LIGHT SNOW IS EXPECTED ACROSS
WESTERN AND CENTRAL NEW YORK LATE TONIGHT INTO SUNDAY MORNING WITH
SOME LAKE EFFECT SNOW AS WELL SOUTHEAST OF THE LAKES. ANY LINGERING
SNOW SHOWERS SOUTHEAST OF THE LAKES MONDAY MORNING WILL END AS HIGH
PRESSURE BUILDS INTO THE REGION. ANOTHER WEAK SYSTEM MAY BRING SOME
LIGHT WET SNOW ON TUESDAY AS TEMPERATURES MODERATE TO A LITTLE ABOVE
AVERAGE AGAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
08Z SURFACE ANALYSIS SHOWS THE ARCTIC FRONT STRETCHING FROM NEAR
SAINT CATHARINES TO JUST SOUTH OF WATERTOWN. STRONG LOW LEVEL COLD
ADVECTION IS DROPPING TEMPERATURES FAST TO THE NORTH OF THAT LINE ON
THE CANADIAN SIDE OF THE BORDER. A WEAK WAVE OF LOW PRESSURE ALONG
THE ARCTIC FRONT WILL SLOW ITS FORWARD PROGRESS FOR AWHILE THIS
MORNING BEFORE COLD AIR FLOODS SOUTHWARD THIS AFTERNOON...ALTHOUGH
IT WILL BE MODIFIED BY THE OPEN AND RELATIVELY WARMER WATERS OF LAKE
ONTARIO.
RADAR IMAGERY EARLY THIS MORNING SHOWS WIDESPREAD LIGHT SNOW ACROSS
ALL OF WESTERN NY WITH A FEW EMBEDDED POCKETS OF HEAVIER SNOW OVER
LAKE ONTARIO WHICH IS LIKELY A LAKE ENHANCED PORTION OF THE ARCTIC
FRONT. ANY LAKE ENHANCEMENT WILL BE SHORT LIVED AS THE WEAK FRONTAL
WAVE DISRUPTS LOW LEVEL FLOW AND PREVENTS ANY ORGANIZED LOW LEVEL
CONVERGENCE. FARTHER EAST THE LIGHT SNOW IS MORE SCATTERED IN NATURE
EAST OF LAKE ONTARIO...AND EVEN MORE SO ACROSS THE FINGER LAKES AND
CENTRAL NY WHERE ONLY A FEW LIGHT FLURRIES ARE FOUND.
FOR TODAY THE MAIN FEATURE OF INTEREST WILL BE A SHARP MID LEVEL
TROUGH...APPARENT IN MOISTURE CHANNEL IMAGERY THIS MORNING DIGGING
THROUGH THE CENTRAL GREAT LAKES. THIS WILL SLOWLY CROSS THE LOWER
LAKES TODAY WITH THE ASSOCIATED ARCTIC FRONT DROPPING SOUTH ACROSS
THE REGION. THE AFOREMENTIONED SURFACE WAVE WILL WEAKEN BY
AFTERNOON AS AN ATLANTIC LOW DEEPENS WELL OFFSHORE OF THE MID
ATLANTIC. AS THE SURFACE WAVE WEAKENS...THE ARCTIC BOUNDARY WILL
ACCELERATE SOUTHEASTWARD.
THE TIMING OF THE ARCTIC BOUNDARY MAKES THE TEMP FORECAST A
CHALLENGE. IT APPEARS THAT THE BOUNDARY WILL ENTER THE NIAGARA
FRONTIER AND NORTH COUNTRY BY DAYBREAK...WITH TEMPS FALLING INTO THE
TEENS THIS MORNING AND REMAINING THERE THROUGH THE REST OF THE DAY.
THE FRONT WILL REACH THE FINGER LAKES AND CENTRAL NY LAST...AND
THOSE AREAS MAY GET CLOSE TO 30 BY MIDDAY BEFORE FALLING BACK
THROUGH THE 20S THIS AFTERNOON.
SNOW WISE...EXPECT THE BULK OF THE STEADIER SNOW TO FOCUS ON WESTERN
NY THIS MORNING THROUGH EARLY AFTERNOON NEAR A WEAK/BROAD
CONVERGENCE ZONE ASSOCIATED WITH THE SURFACE WAVE. THIS WILL ALSO BE
SUPPORTED BY LARGE SCALE FORCING FOR ASCENT AS PVA AND UPPER LEVEL
DIVERGENCE OVERSPREADS WESTERN NY WITH THE APPROACH OF THE MID LEVEL
TROUGH. ALL OF THIS SHOULD SUPPORT A PERIOD OF STEADY SNOW THROUGH
EARLY TO MID AFTERNOON WITH ADDITIONAL AMOUNTS IN THE 2-3 INCH RANGE
IN MOST AREAS...BRINGING TOTALS TO 3-4 INCHES FOR THE NIAGARA
FRONTIER. EXPECT THE HIGHEST AMOUNTS ACROSS CHAUTAUQUA/CATTARAUGUS
COUNTIES WHERE SYNOPTIC SCALE FORCING WILL BE STRONGEST...AND
UPSLOPE FLOW WILL BE MAXIMIZED INTO THE CHAUTAUQUA RIDGE. MAY SEE
ANOTHER 3-5 INCHES THERE TODAY WITH TOTALS OF 4-6 INCHES. A WINTER
WEATHER ADVISORY WAS PREVIOUSLY ISSUED FOR THAT AREA AND WILL REMAIN
IN EFFECT. SNOW AMOUNTS WILL DECREASE WITH EASTERN EXTENT...WITH
AROUND AN INCH IN THE GENESEE VALLEY AND WESTERN FINGER LAKES...AND
LESS THAN AN INCH IN CENTRAL NY AND THE NORTH COUNTRY AS THE
STRONGER FORCING IN WESTERN NY DIGS INTO PENNSYLVANIA THIS AFTERNOON
AND MISSES THAT REGION.
EXPECT THE SNOW TO TAPER OFF FROM NORTHWEST TO SOUTHEAST FROM MID
AFTERNOON THROUGH EARLY EVENING...WITH JUST A FEW LINGERING SNOW
SHOWERS ACROSS HIGHER TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES
THROUGH THE FIRST HALF OF TONIGHT. THERE MAY ALSO BE A FEW SCATTERED
LAKE EFFECT SNOW SHOWERS PERSISTING ACROSS THE WESTERN SOUTHERN TIER
AND OFF LAKE ONTARIO FROM ROCHESTER TO WAYNE COUNTY...BUT LOW
INVERSION HEIGHTS AND VERY LIMITED MOISTURE WILL PREVENT ANYTHING
NOTABLE.
LATER TONIGHT THAT WILL BEGIN TO CHANGE AS ANOTHER WEAK SURFACE
TROUGH APPROACHES THE LOWER LAKES. THIS WILL LIKELY BRING ANOTHER
WIDESPREAD LIGHT SNOW TO WESTERN NY LATE TONIGHT. THIS WILL ALSO
IMPROVE MOISTURE AND INSTABILITY FOR LAKE EFFECT AS LAKE INDUCED
EQUILIBRIUM LEVELS RISE TO 7-8K FEET. BOUNDARY LAYER FLOW ALSO BACKS
A LITTLE LATE TONIGHT...WHICH WILL IMPROVE FETCH. WITH THIS IN
MIND...EXPECT LAKE ENHANCED/UPSLOPE SNOW TO INCREASE LATE TONIGHT
ACROSS THE CHAUTAUQUA RIDGE AND PORTIONS OF SOUTHERN ERIE/WYOMING
COUNTIES. ALSO EXPECT SOME LAKE SNOW TO ORGANIZE OVER WAYNE AND
NORTHERN CAYUGA COUNTIES...AND ALSO LIKELY CLIP PARTS OF MONROE
COUNTY FROM THE LAKESHORE INTO THE EASTERN SUBURBS. WE MAY
EVENTUALLY NEED ADVISORIES IN SOME OF THESE AREAS...BUT GIVEN THIS
WILL BE LATE SECOND AND THIRD PERIOD...WILL HOLD OFF UNTIL THE EVENT
DRAWS A LITTLE CLOSER.
LOW TEMPS TONIGHT WILL BE HELD UP SOME BY CLOUD COVER ACROSS MOST OF
THE AREA WITH LOW TO MID TEENS. EAST OF LAKE ONTARIO AT LEAST SOME
CLEAR TIME THIS EVENING AND NO OVER-LAKE TRAJECTORY WILL ALLOW TEMPS
TO DROP BELOW ZERO.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AN ACTIVE PERIOD SATURDAY NIGHT AND INTO SUNDAY AS LAKE EFFECT SNOW
IS EXPECTED...ENHANCED BY A SOUTHWARD DROPPING ARCTIC FRONT SUNDAY.
SATURDAY NIGHT THE AXIS OF AN UPPER LEVEL TROUGH WILL BE CROSSING
THE REGION...WITH WINDS THROUGH THE BOUNDARY LAYER EXHIBITING TOO
MUCH SHEER...AND LIMITED BOUNDARY LAYER MOISTURE FOR ANY LAKE EFFECT
TO BE ONGOING. SYNOPTIC SNOW WILL BE ENDING ACROSS THE SOUTHERN TIER
EARLY SATURDAY NIGHT WITH LITTLE FURTHER SNOW ACCUMULATION.
TEMPERATURES ALOFT AT 850 HPA WILL BE PLENTY COLD ENOUGH TO SUPPORT
LAKE EFFECT SNOW THOUGH LIFT REMAINS MARGINAL AND MOISTURE IN THE
GOOD SNOW CRYSTAL GROWTH ZONE REMAINS LIMITED TO START.
AS THE NIGHT PROGRESS MOISTURE IN THE LOWER LEVELS INCREASES AND
LAKE INDUCED EQUILIBRIUM LEVELS INCREASE ALONG WITH A DECREASE IN
WIND SHEAR. THIS WILL FAVOR THE FORMATION OF LAKE EFFECT SNOW
BANDS...WITH AN UPSTREAM CONNECTION TO LAKE HURON AND GEORGIAN BAY
LIKELY. THE GREATEST LIFT WILL BE CENTERED OVER LAKE ONTARIO AND
INLAND TOWARDS THE GENESEE VALLEY AND WITH AN UPSTREAM CONNECTION TO
GEORGIAN BAY HERE IS WHERE THE HEAVIEST SNOW BAND IS EXPECTED.
WITH THE UPPER LEVEL WINDS A LITTLE MORE BACKED IN THE LONG WAVE
TROUGH THE FOCUS OF THE LAKE EFFECT SNOW SATURDAY NIGHT IS EXPECTED
TO BE CENTERED MORE FROM SOUTHERN SHORELINE OF LAKE ONTARIO AND
INLAND ACROSS THE NORTHERN GENESEE VALLEY AND TOWARDS THE WESTERN
FINGER LAKES REGION...AND BECOMING LESS LIKELY TOWARDS THE EASTERN
END OF LAKE ONTARIO.
NORTHWEST FLOW ACROSS LAKE ERIE WILL BE PERPENDICULAR...AND LOW
LEVEL LIFT AND CONVERGENCE IS NOT AS GREAT. SNOW OF LAKE ERIE WILL
BE FOCUSED UPON AREAS SOUTH OF BUFFALO...ACROSS SKI COUNTRY AND THE
SOUTHERN TIER.
TOWARDS SATURDAY NIGHT AN ARCTIC FRONT WILL BE DROPPING SOUTHWARD
ACROSS OUR REGION FROM SOUTHERN CANADA. BY 12Z SUNDAY EXPECT THIS
FRONT TO BE PUSHING TOWARDS THE SOUTHERN SHORELINE OF LAKE ONTARIO.
BEHIND THIS FRONT SFC TEMPERATURES WILL DROP INTO THE SINGLE DIGITS
AND LOWER...AND WITH WINDS LIKELY IN THE 5 TO 10 KNOTS RANGE WIND
CHILLS WILL FALL TO -20F OR LOWER SUNDAY MORNING ACROSS PORTIONS OF
THE NORTH COUNTRY. WILL MENTION THESE WIND CHILL TEMPERATURES IN THE
HWO...WITH FURTHER SHIFTS MONITORING FOR ANY WIND CHILL ADVISORIES.
AS THIS ARCTIC FRONT DROPS SOUTHWARD EXPECT THE BAND OF LAKE EFFECT
SNOW OFF LAKE ONTARIO TO BECOME ENHANCED. INCREASING WIND SPEEDS AND
COLD TEMPERATURES WILL CREATE BLUSTERY AND BLOWING SNOW CONDITIONS
EARLY SUNDAY MORNING...AND AS THE FRONT DROPS SOUTHWARD EXPECT THIS
BOUNDARY TO TAKE THE LAKE EFFECT SNOWBAND AND PUSH IT SOUTHWARD WELL
INLAND ACROSS SOUTH OF LAKE ONTARIO. THIS MAY CREATE A SEVERAL HOUR
PERIOD OF REDUCED VISIBILITIES WITHIN THE BLOWING AND FALLING SNOW.
LAKE EFFECT SNOW/SNOW ALONG THE ARCTIC FRONT WILL CONTINUE THROUGH
THE DAY SUNDAY WITH THE FOCUS ALONG THE ARCTIC FRONT. WIND SHEER MAY
DISRUPT THE BANDS THROUGH THE DAY SUNDAY TO HOLD SIGNIFICANT
ACCUMULATIONS FROM OCCURRING AT ANY GIVEN LOCATION. WAA STARTS LATER
IN THE DAY SUNDAY...BUT WITH THE DEEP COLD AIRMASS TEMPERATURES
SUNDAY WILL REMAIN COLD ENOUGH TO SUPPORT LAKE EFFECT
ACTIVITY...WHILE AFTERNOON HIGHS REMAIN BELOW NORMAL.
HIGH PRESSURE FOLLOWING THE ARCTIC FRONT WILL BUILD ACROSS THE NORTH
COUNTRY SUNDAY AND WILL JUST HAVE CHC POPS EARLY SUNDAY ACROSS THE
NORTH COUNTRY...WHILE SOUTHWARD WILL HAVE LIKELY TO CATEGORICAL
POPS.
LAKE EFFECT SNOW WILL DIMINISH SUNDAY NIGHT AND AS THE WINDS
BACK...LIFT NORTHWARD TOWARDS THE EASTERN LAKE ONTARIO REGION
MONDAY. AS THE UPPER LEVEL RIDGE BUILDS ACROSS THE REGION MONDAY
EXPECT SKIES TO CLEAR...WITH TEMPERATURES RISING BACK TO THE
FREEZING MARK...AND NEAR NORMAL.
CLOUDS WILL INCREASE THROUGH THE NIGHT MONDAY NIGHT AS THE NEXT
SYSTEM FROM THE WEST NEARS THE REGION WITH LIGHT SNOW RETURNING LATE
TO WNY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SEVERAL UPPER LEVEL SHORT WAVES THROUGH A SPLIT FLOW THIS TIME
PERIOD WILL CREATE AN ACTIVE TIME PERIOD FOR THE LONG RANGE...THOUGH
EACH SINGLE SYSTEM AT PRESENT MOMENT DOES NOT APPEAR SIGNIFICANT.
WITH A RETURN TO A MORE ZONAL FLOW THIS PERIOD TEMPERATURES WILL
AVERAGE AROUND NORMAL...WITH ANY GREAT DEPARTURES FROM NORMAL COMING
ON ANY PHASING OF THE NORTHERN AND SOUTHERN SHORTWAVES...THEREBY
AMPLIFYING THE FLOW SOME.
TUESDAY THE GFS/ECMWF/GGEM BRING A WEAK SHORT WAVE EJECTING FROM THE
SOUTHWEST ACROSS THE EASTERN GREAT LAKES. TEMPERATURES ALOFT ON BOTH
THE GFS/ECMWF RANGE FROM -6 TO -8C AND WITH THE 06Z GEFS MEMBERS
SUPPORTING ALL SNOW WILL KEEP THE P-TYPE AS SNOW FOR VALENTINES DAY.
FOR NOW WILL LEAVE AS HIGH CHANCE POPS...AS QPF IS ON THE LIGHT SIDE
AND THE SHORT WAVE IS EXPECTED TO FLATTEN OUT AS IT NEARS THE NORTH
EAST. TEMPERATURES TUESDAY UNDER A CLOUDY SKY WILL NOT STRAY MUCH
FROM NORMAL.
WILL HAVE SNOW TAPERING OFF TUESDAY NIGHT WITH THE FLATTENING
SHORTWAVE PASSING BY.
TIMING AND STRENGTH OF THE NEXT SHORT WAVE...THIS TIME IN THE
NORTHERN BRANCH OF THE JET STREAM REMAINS UNCERTAIN. BOTH THE 12Z
GFS AND 12Z ECMWF HAVE BOTH BEEN HINTING AT A SHORT WAVE
CROSSING...THOUGH TIMING AND STRENGTH HAVE BEEN FLUCTUATING. WILL
CONTINUE WITH LOW CHC POPS FOR WEDNESDAY.
BOTH THE GFS AND ECMWF HAVE A SFC HIGH PRESSURE ACROSS THE REGION
WEDNESDAY NIGHT AND INTO THURSDAY MORNING AND THIS FEATURE WILL
ALLOW FOR DIMINISHING POP CHCS THOUGH WITH LOW LEVEL MOISTURE
REMAINING...AND POSSIBLY TRAPPED BELOW AN INVERSION WILL MAINTAIN
MOSTLY CLOUDY SKY CONDITIONS.
BOTH THE OPERATIONAL RUNS OF THE GFS AND ECMWF BRING ANOTHER
SHORTWAVE ACROSS THE EASTERN GREAT LAKES LATER THURSDAY AND
INTO FRIDAY ALONG WITH AN INCREASE IN MOISTURE. WILL BRING CHC POPS
BACK TO THE REGION LATE THURSDAY TO THE SOUTHERN TIER...AND THROUGH
THE NIGHT THURSDAY AND INTO FRIDAY.
PRECIPITATION TYPE WEDNESDAY THROUGH FRIDAY IS CHALLENGING AS 850S
RISE TO NEAR -4C ON THE GFS WEDNESDAY...THOUGH THE ECMWF MAINTAINS A
DEEPER COOL POOL OVER THE EASTERN GREAT LAKES. WILL HAVE BOTH RAIN
AND SNOW MENTIONED IN THE GRIDS FOR WEDNESDAY...
A MILDER RETURN FLOW BEHIND THE DEPARTING SFC HIGH THURSDAY AND
FRIDAY WILL ALSO ALLOW FOR PRECIPITATION TO COME AS A MIX OF RAIN AND
SNOW FOR LATER THURSDAY AND FRIDAY ACROSS THE REGION.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
RADAR TRENDS AROUND THE REGION SHOW SNOW SHOWERS OVER WESTERN AND
NORTHERN LAKE ONTARIO CLOSER TO THE FRONTAL BOUNDARY...AND MAY
AFFECT KART DOWNSTREAM WITH IFR CONDITIONS. WILL EXPECT GENERALLY
LIGHT SNOW ACROSS THE REGION WITH MVFR TO UPPER RANGE IFR
CONDITIONS...THE IFR MOSTLY DUE TO RESTRICTED VSBY.
CONDITIONS WILL LOWER SIGNIFICANTLY AT MOST SITES SATURDAY
MORNING...AS A FRONTAL BOUNDARY DROPS ACROSS THE REGION. THIS
FRONTAL PASSAGE WILL KEY A MORE INTENSE PERIOD OF SNOW...WITH IFR
OR LOWER CONDITIONS LIKELY TOWARD DAYBREAK SATURDAY INTO SATURDAY
MORNING.
AN IMPROVEMENT TO VFR CONDITIONS AFTER 21Z ON SATURDAY AS A DRIER
AIRMASS ARRIVES BEHIND THE PASSING COLD FRONT...BUT NOT TO LAST LONG
AS LAKE EFFECT SNOW ON COLD NORTHERLY WINDS BRINGS IFR CONDITIONS
BACK DURING SATURDAY NIGHT.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...PERIODS OF IFR OR LOWER IN LAKE EFFECT
SNOW SHOWERS.
MONDAY...MAINLY VFR.
TUESDAY AND WEDNESDAY...VFR/MVFR IN CHC OF SNOW.
&&
.MARINE...
WINDS WILL BECOME NORTH TO NORTHEAST AND INCREASE THIS MORNING ON
LAKES ERIE AND ONTARIO WITH THE PASSAGE OF AN ARCTIC COLD FRONT.
THIS WILL PRODUCE SMALL CRAFT ADVISORY CONDITIONS ALONG THE SOUTH
SHORES OF BOTH LAKES TODAY THROUGH TONIGHT. ON SUNDAY WINDS WILL
BECOME MORE WNW WITH SOLID SMALL CRAFT CONDITIONS RIGHT THROUGH
MONDAY BEFORE WINDS AND WAVES FINALLY DIMINISH MONDAY NIGHT.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
NYZ019-020.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 5 AM EST
MONDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 5 AM EST MONDAY FOR
LOZ043>045.
SMALL CRAFT ADVISORY UNTIL 10 PM EST SUNDAY FOR LOZ042.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...WCH
MARINE...HITCHCOCK
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