FXUS61 KBUF 230824
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
324 AM EST WED DEC 23 2009
.SYNOPSIS...
A DISTURBANCE DROPPING SOUTH FROM QUEBEC WILL BRING SOME MORE SNOW
SHOWERS TO THE AREA TODAY...PARTICULARLY ACROSS THE EASTERN LAKE
ONTARIO REGION AND SITES JUST SOUTH OF LAKE ONTARIO. HIGH PRESSURE
NOSING SOUTHWARDS FROM NORTHERN ONTARIO WILL THEN BRING US FAIR
TRANQUIL WEATHER TONIGHT THROUGH THURSDAY. THIS WILL RESULT IN IDEAL
TRAVEL CONDITIONS LEADING INTO CHRISTMAS...BUT A LARGE STORM WELL TO
OUR WEST COULD SPREAD SOME RAIN AND FREEZING RAIN OVER US CHRISTMAS
DAY THROUGH CHRISTMAS NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE CIRCULATION BETWEEN LOW PRESSURE HEADING OUT INTO THE ATLANTIC
AND HIGH PRESSURE BUILDING EAST TOWARD JAMES WILL MAINTAIN A
NORTHWEST FLOW OF COLD AIR ACROSS OUR AREA THROUGH THIS FORECAST
PERIOD. IN TERMS OF PCPN...A COMBINATION OF SYNOPTIC SCALE
INFLUENCES AND LIMITED LAKE EFFECT WILL IMPACT PARTS OF THE CWA
TODAY INTO EARLY TONIGHT.
A SHORT WAVE THAT IS PUSHING SOUTH ACROSS CENTRAL NEW YORK EARLY
THIS MORNING IS GENERATING SCATTERED SNOW SHOWERS/FLURRIES...WITH
SOME LAKE ENHANCEMENT EVIDENT OVER OSWEGO COUNTY AND PARTS OF THE
WESTERN SOUTHERN TIER WHERE THE NORTHWEST UPSLOPE FLOW IS ALSO
COMING INTO PLAY. SUBSIDENCE BEHIND THIS IMPULSE WILL CAUSE THE
LIGHT SNOW OVER WESTERN NEW YORK AND THE GENESEE VALLEY TO TAPER OFF
TO SCATTERED FLURRIES LATER THIS MORNING. THE LACK OF LOW LEVEL
MOISTURE AND THE LOWERING SUBSIDENCE INVERSION SHOULD RESULT IN
LITTLE OR NO ACCUMULATION ACROSS WESTERN NEW YORK.
FARTHER TO THE EAST...A SECOND SHORT WAVE IS FORECAST TO DROP SOUTH
SOUTH ACROSS NORTHERN NEW YORK STATE LATER THIS MORNING THROUGH MID
AFTERNOON. THE ADDED LIFT FROM THIS IMPULSE AND THE PRESENCE OF
DEEPER MOISTURE ACROSS THE EASTERN PART OF THE STATE WILL KEEP
SCATTERED SNOW SHOWERS GOING ACROSS THE NORTH COUNTRY THROUGH A GOOD
PART OF THE DAY. THE SNOW WILL BECOME ENHANCED SOUTHEAST OF LAKE
ONTARIO WHERE THE NAM BUFKIT PROFILES SHOW A DEEPER LAYER OF
FAVORABLE ICE CRYSTAL GROWTH INTERSECTING THE DEEPER MOISTURE. BASED
ON THIS...WILL MAINTAIN THE LIKELY POPS FROM WAYNE TO OSWEGO
COUNTIES. THE RELATIVELY LOW LAKE INDUCED EQUILIBRIUM LEVELS AND
MINIMAL CAPES SHOULD KEEP ACCUMULATIONS BELOW ADVISORY CRITERIA.
FOR TONIGHT...ANY LINGERING LAKE EFFECT SNOW SHOULD END EARLY
TONIGHT AS THE LOW LEVEL SHEAR INCREASES. OTHERWISE...EXPECT MOSTLY
CLOUDY SKIES TO BE THE RULE AS A SHALLOW LAYER OF MOISTURE REMAINS
TRAPPED BELOW THE INVERSION WHICH WILL BE STRENGTHENED BY WARM AIR
ADVECTION ALOFT. THE ANTICIPATED CLOUD COVER AND WARM AIR ADVECTION
PATTERN WILL HELP TO KEEP AREA TEMPERATURES FAIRLY STEADY
TONIGHT...ESPECIALLY ACROSS WESTERN NEW YORK.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THURSDAY WILL PROVE TO BE ONE OF THE THE NICEST WEATHER DAYS OF THE
WEEK AS A HIGH AMPLITUDE RIDGE WILL BE POSITIONED OVER THE EASTERN
THIRD OF THE COUNTRY. WHILE THERE WILL NOT BE ANY PRECIPITATION TO
WORRY ABOUT ON THURSDAY...MOST OF THE REGION WILL STILL HAVE TO DEAL
WITH A FAIR AMOUNT OF CLOUD COVER. FORECAST PROFILE SOUNDINGS
SUGGEST THAT A LOT OF LOW LEVEL MOISTURE WILL BE TRAPPED BENATH A
STRONG SUBSIDENCE INVERSION...SO WE WILL LIKELY HAVE TO WAIT UNTIL
THE AFTERNOON TO GET ANY APPRECIABLE SUNSHINE. IN ANY CASE...THE DRY
WEATHER THURSDAY WILL PROMOTE PROBLEM FREE CONDITIONS FOR LAST
MINUTE HOLIDAY SHOPPERS AND TRAVELERS.
THE STRONG RIDGE WILL SLOWLY CROSS THE FORCEAST AREA ON CHRISTMAS
EVE AS A SURFACE HIGH WILL GRUDGINGLY CROSS NORTHERN QUEBEC. THIS
SFC HIGH WILL NOSE SOUTHWARDS ACROSS EASTERN NEW YORK TO THE MID
ATLANTIC COAST. MEANWHILE WELL TO OUR WEST...AN EXPANSIVE UPPER LOW
WILL BECOME CONSOLIDATED OVER THE CENTRAL PLAINS. THE CORRESPONDING
SFC LOW (< 990MB) WILL LIFT NORTHWARDS ACROSS MISSOURI. THIS
SYNOPTIC SET UP WILL LIMIT THE EASTWARD ADVANCE OF ANY PCPN FROM THE
SYSTEM...SO ALL OF OUR REGION SHOULD BE ABLE TO GET THROUGH
CHRISTMAS EVEN WITHOUT ANY PRECIPITATION. WILL FOLLOW THE TREND OF
OUR CONTINUITY AND GUIDANCE FROM THE ECMWF...GFS AND SREF WHICH WILL
KEEP PCPN TO OUR WEST. GOOD FOR US...BAD FOR SANTA.
THE UPPER LEVEL RIDGE WILL CONTINUE TO VERY SLOWLY CROSS QUEBEC AND
NEW ENGLAND ON CHRISTMAS DAY WHILE THE DEEP PLAINS STORM WILL BECOME
STACKED AND FURTHER CONSOLIDATE OVER IOWA. WHILE WEAK WARM ADVECTION
WILL CONTINUE ALOFT...THE CLOSE PROXIMITY OF THE RIDGE WILL KEEP THE
LOW LEVELS UNCOMFORTABLY CLOSE TO FREEZING. AS HAS BEEN ADVERTISED
FOR SEVERAL DAYS NOW...THIS WILL LIKELY LEAD TO PROBLEMS DUE TO PCPN
TYPE. PATTERN RECOGNITION AND SIMPLE CLIMATOLOGY OF A SCENARIO WHERE
A DEEP STORM IS SO FAR TO OUR WEST WITH A COLD RIDGE ANCHORED OVER
EASTERN CANADA RAISES FLAGS/CONCERNS ABOUT FREEZING RAIN.
THIS CASE WILL BE NO DIFFERENT...BUT WITH WEAK TEMPERATURE ADVECTION
IN THE LOW LEVELS COMES WEAK MOISTURE ADVECTION. THE VARIOUS
GUIDANCE PACKAGES HAVE BEEN SLOWER AND SLOWER WITH THE ONSET OF THE
PCPN...AND THIS MAY TURN OUT TO BE A GOOD THING. MANY AREAS MAY BE
ABLE TO WARM ABOVE 32 BEFORE THE PCPN BEGINS ON CHRISTMAS DAY...BUT
FOR THOSE WESTERN AREAS THAT DO NOT...THERE COULD BE A FEW HOURS
WHERE FREEZING RAIN COULD HAVE A BIG IMPACT ON AREA ROADWAYS.
FORECAST POINT SOUNDINGS FROM BOTH THE GFS AND NAM/WRF SUGGEST THAT
TEMPS CLIMB ABV FREEZING FOR MOST AREAS BY EARLY-MID AFTERNOON ON
CHRISTMAS DAY...WITH THE ONLY AREAS OF CONCERN BEING THE DEEPER
SOUTHERN TIER VALLEYS AND SITES EAST OF LK ONTARIO. FOR THE
LATTER...THE PROFILES SUPPORT A MIX OF SLEET AND FREEZING RAIN. POPS
ON CHRISTAMS DAY WILL RANGE FROM CAT OVER THE WESTERN COUNTIES TO
LOW CHC POPS EAST OF LK ONTARIO WHERE IT MAY END BEING DRY UNTIL
NIGHTFALL.
FOR CHRISTMAS NIGHT...THE WELL STACKED STORM SYSTEM WILL BE NEARLY
STATIONARY IN THE VCNTY OF IOWA WHILE ITS ASSOCIATED FRONTAL
BOUNDARY WILL PUSH ACROSS THE OHIO VALLEY. A DEEP SWATH OF MOISTURE
(VALUES +2 STD ABV NORMAL) AHEAD OF THIS SLOW MOVING FRONT WILL MOVE
ACROSS OUR REGION...WITH A DIFFLUENT FLOW AND FAIRLY STRONG JET
DYNAMICS SUPPORTING WIDESPREAD CAT POPS. THESE POPS ARE HIGHER THAN
GUIDANCE AND GENERALLY HIGHER THAN THOSE FROM SURROUNDING WFO'S.
PCPN TYPE WILL REMAIN A PROBLEM CHRISTMAS NIGHT. SINCE THE OCCLUDED
FRONT IS NOT FORECAST TO CROSS THE FAR WESTERN COUNTIES UNTIL VERY
LATE...THE COLD AIR IN ITS WAKE WILL OBVIOUSLY STILL BE TO OUR WEST.
THIS SHOULD KEEP MAINLY LIQUID PCPN IN PLACE...ALTHOUGH SOME
FREEZING RAIN AND POSSIBLY SLEET MAY BE AN ISSUE FOR SITES EAST OF
LK ONTARIO.
ON SATURDAY...THE FRONTAL BOUNDARY WILL FINALLY CROSS THE FORECAST
AEA WHUILE THE PARENT STACKED STORM WILL WOBBLE ACROSS WISCONSIN.
THE COLD AIR IN THE WAKE OF THE FRONTAL PASSAGE WILL BE SLOW TO
SUFFICIENTLY DEEPEN FOR WIDESPREAD SNOW SHOWERS...EXCEPT OVER THE
FAR WESTERN COUNTIES. WILL THEREFORE KEEP THE IDEAL OF A SLOW WEST
TO EAST TRANSITION SATURDAY AND SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE CLOSED 500 MB LOW WILL CONTINUE ITS SLOW EASTWARD PROGRESSION...
BRINGING COOLER AIR ALOFT AND GENERALLY AN UNSETTLED PATTERN. BY
SUNDAY...IT SHOULD BE COLD ENOUGH FOR ANY PRECIPITATION THAT DOES
FALL TO BE SNOW. THE CLOSE PROXIMITY OF THE UPPER LOW (BUT UNCERTAIN
EXACT TRACK) WILL PREVENT ANY SIGNIFICANT SYNOPTIC LOWS FROM
DEVELOPING...BUT MAY RESULT IN INSTABILITY OR LAKE EFFECT SNOW
SHOWERS THROUGH THE PERIOD.
LOOKS TO BE A LESS THAN IDEAL SET UP FOR LAKE EFFECT FOR THE MOST
PART...WITH A GFS/EUROPEAN CONSENSUS BRINGING THE UPPER LOW TO OUR
SOUTH. HOWEVER...WITH 850 MB TEMPS DROPPING...THERE WILL BE AVAILABLE
LAKE INDUCED ENERGY...WITH SUBTLE FEATURES THE KEY. GENERALLY FOR
THE PERIOD...WITH MAINTAIN CHANCE POPS THROUGHOUT...WITH SLIGHTLY
HIGHER END CHANCE POPS IN THE TYPICALLY FAVORABLE LAKE EFFECT
REGIONS. WHILE A MAJOR EVENT IS NOT EXPECTED...AS OFTEN IS THE
CASE...PERSISTENT BANDS COULD PRODUCE LOCALLY DECENT SNOWFALL...
ALTHOUGH MOST LOCATIONS WILL NOT GET ANY SIGNIFICANT SNOWFALL
THROUGH THIS PERIOD. TEMPERATURES WILL BE COOL...BUT WITH MOSTLY
CLOUDY SKIES SHOULD HAVE MINIMAL DIURNAL SWINGS.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
A SHORT WAVE ROTATING ACROSS THE AREA ON THE WEST SIDE OF A
DEPARTING UPPER LOW WILL PRODUCE RATHER WIDESPREAD MVFR CIGS THE
REST OF THE NIGHT INTO MUCH OF THE REST OF THE TAF PERIOD. SOME
LAKE SNOWS MAY PRODUCE IFR VSBYS AT TIMES SOUTHEAST OF LAKE
ONTARIO.
OUTLOOK...
WEDNESDAY NIGHT...MVFR.
THURSDAY...VFR WITH AREAS OF MVFR.
FRIDAY...DETERIORATION TO IFR/MVFR WITH RAIN BECOMING
LIKELY...POSSIBLY STARTING AS A PERIOD OF FREEZING RAIN.
SATURDAY...IFR/MVFR WITH A MIX OF RAIN AND SNOW LIKELY.
SUNDAY...MVFR/VFR WITH A CHANCE OF SNOW SHOWERS.
&&
.MARINE...
SMALL CRAFT ADVISORIES WILL REMAIN IN PLACE FOR THE NEW YORK
NEARSHORE WATERS OF LK ONTARIO THROUGH AT LEAST THIS AFTERNOON.
STRONG HIGH PRESSURE NOSING SOUTH FROM NORTHERN ONTARIO WILL PRODUCE
FRESH TO STRONG NORTHWESTERLIES ACROSS LAKE ONTARIO TODAY...WHILE A
WEAKER SFC PRESSURE GRADIENT WILL RESULT IN JUST MODERATE
NORTHWESTERLIES OVER LK ERIE.
DURING THE COURSE OF TONIGHT...THE EASTWARD DRIFTING HIGH PRESSURE
WILL WEAKEN THE GRADIENT OVER LAKE ONTRAIO...THEREBY LOWERING BOTH
THE WINDS AND CORRESPONDING WAVES. ALL SMALL CRAFT ADVISORIES SHOULD
BE ALLOWED TO EXPIRE BY MIDNIGHT.
ON THURSDAY...THE SFC HIGH WILL DRIFT A LITTLE FURTHER TO THE EAST.
THIS ALLOW WINDS TO VEER TO THE NORTHEAST ACROSS BOTH LAKES WITH
WINDS AND WAVES REMAINING BELOW SCA CRITERIA. THE WINDS WILL FRESHEN
A BIT THURSDAY NIGHT AS THEY BECOME MORE EASTERLY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LOZ043>045.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
LOZ042.
&&
$$
SYNOPSIS...RSH
NEAR TERM...TJP
SHORT TERM...RSH
LONG TERM...APFFEL/RSH
AVIATION...SAGE
MARINE...RSH
