000
FXUS61 KBUF 272026
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
326 PM EST MON DEC 27 2010
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL CONTINUE THROUGH TUESDAY WITH
SCATTERED FLURRIES AND SNOW SHOWERS. A MORE ORGANIZED AREA OF LAKE
EFFECT SNOW WILL PRODUCE SOME ACCUMULATION SOUTHEAST OF LAKE ONTARIO
LATER TONIGHT INTO TUESDAY. A WARMING TREND WILL THEN BEGIN WITH
TEMPERATURES SOARING TO WELL ABOVE AVERAGE BY THE END OF THE WEEK.
THE THAW IS EXPECTED TO LAST ABOUT THREE DAYS...WITH TEMPERATURES
RETURNING TO NEAR AVERAGE BY SUNDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
NORTHWEST FLOW CONTINUES TO PRODUCE SCATTERED SNOW SHOWERS ACROSS
MUCH OF WESTERN AND CENTRAL NY THIS AFTERNOON. HIGH RESOLUTION MODEL
DATA SHOWS AN INTERESTING SETUP...WITH A POOL OF COLDER 850MB TEMPS
OVER NEW YORK STATE AND SOMEWHAT WARMER TEMPS ALOFT OVER SOUTHERN
ONTARIO PROVINCE...WITH NORTHWEST FLOW PRODUCING WARM ADVECTION AND
IMPLIED WEAK LIFT. THIS IS ALSO BEING SUPPORTED BY WEAK LAKE
ENHANCEMENT OFF LAKE ONTARIO AND UPSLOPE FLOW INTO THE HIGHER
TERRAIN. THIS SAME BASIC PATTERN WILL CONTINUE TONIGHT...WITH SOME
SUBTLE DIFFERENCES AS THE BOUNDARY LAYER WINDS SLOWLY BACK.
FOR MUCH OF THE AREA FROM OSWEGO COUNTY WEST INTO THE FINGER LAKES
AND WESTERN NY EXPECT MORE OF THE SAME TONIGHT WITH SCATTERED
FLURRIES AND LIGHT SNOW SHOWERS PRODUCING A FRESH DUSTING TO AN INCH
IN SOME SPOTS. MESOSCALE MODEL GUIDANCE CONTINUES TO HINT AT A MORE
ORGANIZED LAKE EFFECT SNOW BAND DEVELOPING OVERNIGHT JUST EAST OF
ROCHESTER AS THE BOUNDARY LAYER FLOW BACKS ENOUGH TO SUPPORT AN
UPSTREAM CONNECTION WITH GEORGIAN BAY. LAKE INSTABILITY IS
MARGINAL...BUT NAM POINT SOUNDINGS OVER LAKE ONTARIO SUGGEST A
SEVERAL HOUR PERIOD WHERE LAKE INDUCED EQUILIBRIUM LEVELS RISE TO
6-7K FEET. THE AIRMASS IS STILL JUST COLD ENOUGH TO ALSO SUPPORT A
FAVORABLE TEMPERATURE RANGE FOR DENDRITIC CRYSTAL GROWTH IN THE
CLOUD BEARING LAYER. NAM/GEM AND WORKSTATION WRF ALL DEVELOP A
DECENT BAND OVER WAYNE/NORTHERN CAYUGA COUNTIES AROUND MIDNIGHT...
SHIFTING SLOWLY EAST TOWARDS OSWEGO COUNTY ON TUESDAY.
BY MID MORNING TUESDAY...CONDITIONS BEGIN TO BECOME LESS FAVORABLE
AS THE AIRMASS SLOWLY WARMS. LAKE INDUCED EQUILIBRIUM LEVELS FALL TO
BELOW 5K FEET...AND THE AIRMASS UPSTREAM BECOMES TOO WARM TO SUPPORT
ANY LAKE RESPONSE OFF GEORGIAN BAY...EFFECTIVELY SHUTTING OFF ANY
UPSTREAM CONNECTION THAT DEVELOPS TONIGHT. THUS...EXPECT THE LAKE
BAND TO SLOWLY WEAKEN ALTHOUGH NOT END ALTOGETHER ON TUESDAY AS IT
SHIFTS SLOWLY NORTH ACROSS OSWEGO COUNTY.
OFF LAKE ERIE...EXPECT ANY LAKE RESPONSE TO BE VERY LIMITED OR
NON-EXISTENT WITH SOMEWHAT MILDER 850MB TEMPS...LACK OF AN UPSTREAM
CONNECTION AND A COLDER LAKE. THAT SAID...UPSLOPE FLOW AND WEAK WARM
AIR ADVECTION MAY PRODUCE OCCASIONAL PERIODS OF LIGHT SNOW ACROSS
THE HIGHER TERRAIN OF THE CHAUTAUQUA RIDGE TONIGHT THROUGH TUESDAY.
AS FAR AS THE FORECAST DETAILS GO...CLOSE CALL FOR MONROE COUNTY
INITIALLY AROUND MIDNIGHT AS THE BAND GETS GOING. WILL GO WITH 2-4
INCHES IN THE EASTERN SUBURBS FROM IRONDEQUOIT BAY TO WEBSTER...WITH
AN INCH OR TWO EXTENDING BACK ACROSS THE CITY TO THE AIRPORT. LESS
FARTHER SOUTH AND WEST. ACROSS WAYNE AND NORTHERN CAYUGA COUNTY WILL
GO WITH 3-6 INCH ACCUMULATIONS LATER TONIGHT INTO THE FIRST HALF OF
TUESDAY. FARTHER EAST ACROSS OSWEGO COUNTY WILL GO WITH 2-4 INCHES
ON TUESDAY AS A WEAKENING BAND LIFTS SLOWLY NORTH ACROSS THE COUNTY.
MAY SEE SOME SPOTTY 1-2 INCH AMOUNTS TONIGHT INTO TUESDAY ACROSS THE
HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER. OUTSIDE OF THESE
AREAS...ANY ACCUMULATION SHOULD BE LESS THAN AN INCH.
TEMPERATURES WILL NOT DROP MUCH TONIGHT...AND IN FACT WILL RISE IN
MOST AREAS OVERNIGHT WITH CLOUD COVER AND ONGOING LOW LEVEL WARM
ADVECTION. THE SLOW MODERATING TREND WILL BEGIN ON TUESDAY WITH THE
LOWER ELEVATION LAKE PLAINS TOPPING OUT AROUND 30...WITH MID TO
UPPER 20S ACROSS HIGHER TERRAIN.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY/...
THE REGION WILL BE BETWEEN TWO SYSTEMS ON TUESDAY NIGHT...WITH
HIGH PRESSURE ACROSS THE TENNESSEE VALLEY AND LOW PRESSURE IN THE
CANADIAN MARITIMES. FOR US...THE SIGNIFICANT FEATURE WILL BE A
WEAK SHORTWAVE CROSSING...WHICH MAY SPARK SOME LAKE EFFECT SNOW
EAST OF LAKE ONTARIO.
OFF LAKE ERIE...A VERY SHALLOW INVERSION RESULTS IN MEAGER LAKE
INDUCED CAPES AND MARGINAL SNOW GROWTH. TYPICALLY THIS SCENARIO WILL
PRODUCE JUST CLOUDS...SO EXPECT NAM/RGEM ARE OVERDONE IN THEIR QPF
FIELDS. WHILE UPSLOPING ON THE CHAUTAUQUA MAY PRODUCE SOME VERY LIGHT
PRECIPITATION OR DRIZZLE...KEEP POPS IN THE SLIGHT CHANCE RANGE FOR
NOW.
A SLIGHTLY BETTER SET UP FOR LAKE ONTARIO...WITH THE INVERSION
SLIGHTLY DEEP AS IT IS CLOSER TO THE SHORTWAVE...ALLOWING FOR TEMPS
TO DROP TO AROUND -10C AT THE TOP OF THE INVERSION. WHILE LESS THAN
IDEAL FOR SNOW GROWTH...FEEL IT WILL LIKELY BE JUST ENOUGH FOR SNOW
TO FORM. 850 MB WINDS DO NOT LINE UP...BUT GIVEN THIS IS ABOVE THE
INVERSION...THIS IS EXPECTED. THE MAIN LIMITING FACTOR IS LACK
OF INSTABILITY...WITH THE INVERSION AND MODESTLY COOL AIR LIMITING
LAKE INDUCED CAPES TO 100 TO 150 J/KG...THERE IS A LIMITED AMOUNT OF
ENERGY TO WORK WITH. NAM12/WRF/RGEM ALL KEY ON A FAIRLY SIGNIFICANT
BAND DEVELOPING...WITH TERRAIN ENHANCED QPFS OF A QUARTER INCH NEAR
THE TUG HILL. GIVEN OTHER LIMITING FACTORS...EXPECT THIS IS WELL
OVERDONE...THOUGH IT WILL LIKELY SNOW...FEEL MUCH MORE MODEST
AMOUNTS ARE IN ORDER. FEEL SNOWFALL RATES WILL NOT BE
IMPRESSIVE...WITH PERSISTENCE AND UPSLOPING ENOUGH TO SQUEAK OUT A
INCH OR TWO ON EASTERN PORTIONS OF THE TUG HILL. SREF PROVIDES A
GOOD CONSENSUS POSITION OF THE SHORTWAVE...WITH IT TAKING EXITING
THE SHORTWAVE INTO NEW ENGLAND WEDNESDAY AFTERNOON. THIS SHOULD SHUT
DOWN WEDNESDAY AFTERNOON.
OUTSIDE OF THIS...EXPECT TUESDAY NIGHT AND WEDNESDAY TO BE MOSTLY
CLOUDY...WITH LIMITED DIURNAL VARIATION IN TEMPERATURES DUE TO THE
LINGERING CLOUD COVER WHICH IS TRAPPED UNDERNEATH THE INVERSION.
THE PATTERN CHANGES IN A SIGNIFICANT WAY FOR THE LATTER HALF OF THE
WEEK. A NEARLY UNANIMOUS MODEL CONSENSUS BUILDS AN UPPER LEVEL RIDGE
EAST...WHICH ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE REGION
STARTING WEDNESDAY NIGHT. THE RIDGE AXIS WILL BUILD ACROSS THE
REGION THURSDAY...THEN GRADUALLY SHIFT JUST EAST OF THE REGION
THROUGH FRIDAY. LARGELY...THIS SHOULD BRING FAIR WEATHER AND
MODERATING TEMPERATURES TO THE REGION. INITIALLY...WARM AIR ALOFT
MAY STRUGGLE TO MIX TO THE SURFACE...BUT AS THE RIDGE AXIS SHIFTS
EAST...WINDS SHIFTING TO THE SOUTHEAST SHOULD HELP DOWNSLOPE AND
BOTH WARM TEMPERATURES...AND HELP ERODE LINGERING MOISTURE BENEATH
THE INVERSION. BY FRIDAY...EXPECT HIGHS IN THE MID-40S NEAR THE
LAKES...AND SLIGHTLY COOLER SOUTH AND EAST. DUE TO THE ILL-DEFINED
WARM FRONTAL BOUNDARY...AND MODEST FLOW ALOFT...WILL ONLY CARRY A
SLIGHT CHANCE OF PRECIPITATION ON FRIDAY. EXPECT MUCH OF THE MODEL
QPF IS ACTUALLY DUE TO SOUTHERLY UPSLOPE...WHICH TYPICALLY HAS A
MINIMAL IMPACT ON OUR CWA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
ABOVE AVERAGE MODEL AGREEMENT CONTINUES...WITH GFS/GGEM/EUROPEAN IN
GENERAL AGREEMENT WITH FAIRLY MINOR DIFFERENCES IN TIMING FOR THIS
RANGE. A VERTICALLY STACKED LOW WILL TRACK ACROSS THE UPPER LAKES
FRIDAY NIGHT...AND INTO CANADA THROUGH THE WEEKEND. THIS WILL PUSH A
SIGNIFICANT COLD FRONT ACROSS THE REGION...WITH CONSENSUS TIMING
BRINGING THE FRONT ACROSS LATE SATURDAY INTO SATURDAY NIGHT.
TEMPERATURES WILL WARM AHEAD OF THE FRONT...WITH UNSEASONABLY WARM
TEMPERATURES EXPECTED FRIDAY NIGHT...AS TEMPERATURES ARE LIKELY TO
DROP VERY LITTLE AS THE NIGHT GOES ON. EXPECT A BRIEF RISE TO THE
MID TO UPPER 40S IMMEDIATELY AHEAD OF THE FRONT ON SATURDAY...THOUGH
IT WILL LIKELY BE CLOUDY FOR MOST OF THE DAY. BASED ON MODEL
AGREEMENT...BOOST POPS TO LIKELY FOR SATURDAY AHEAD OF THE FRONT.
DOESN/T LOOK LIKE A MAJOR SOAKER...BUT EXPECT A PERIOD OF RAIN FOR
ALL...WITH TIMING QUESTIONS THE MAIN REASON POPS AREN/T EVEN HIGHER.
QPFS A QUARTER TO HALF INCH SEEM REASONABLE FOR NOW...AS FAIRLY
SHARP DYNAMIC LIFT ALONG THE BOUNDARY SUGGESTS A FAIRLY SOLID LINE
OF RAIN OR RAIN SHOWERS. WHILE MIXED PRECIPITATION CANNOT BE
COMPLETELY RULED OUT WITH THIS...DAYTIME PASSAGE WILL REDUCE THE
POTENTIAL FOR MIXED PRECIPITATION WITH THE FRONT.
AS THE FRONT CROSSES...AN ABRUPT DROP IN TEMPERATURES AT ALL LEVELS
WILL OCCUR. WITH A BRISK SW FLOW FORECAST TO DEVELOP BEHIND THE
BOUNDARY...A ROUND OF LAKE EFFECT SNOW SHOWERS IS LIKELY. 850 MB
TEMPS SHOULD COOL TO -13 C OR COLDER...PROVIDING AMPLE INSTABILITY
FOR LAKE EFFECT. TOO FAR TO PIN DOWN EXACT LOCATIONS...BUT WILL
CARRY LIKELY POPS IN AREAS WHICH TRADITIONALLY DO WELL IN A SW FLOW
FOR SATURDAY NIGHT. FLOW WILL BACK AND BECOME DRIER THROUGH SUNDAY
AND SUNDAY NIGHT...WITH MODEL VARIATIONS FORCING A MORE GENERIC
CHANCE POP FORECAST. BASICALLY SUNDAY LOOKS MUCH COOLER THAN
SATURDAY...WITH SCATTERED SNOW SHOWERS ACROSS THE REGION.
HIGH PRESSURE WILL LIKELY RIDGE FROM THE SOUTH ON MONDAY...WITH NEAR
CLIMO TEMPERATURES EXPECTED.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
AT 18Z A BATCH OF LAKE ENHANCED AND OROGRAPHIC/WAA LIFT SNOW SHOWERS
CONTINUE TO ERODE ACROSS THE AREA AS DAYTIME MIXING AND LOSS OF LIFT
FROM WAA OCCURS. EXPECT MVFR CIGS ACROSS THE NIAGARA FRONTIER AND
CENTRAL NEW YORK TO IMPROVE TO VFR FOR A PERIOD OF TIME THIS
AFTERNOON AND EARLY EVENING. ACROSS THE SOUTHERN TIER WITH UPSLOPE
FLOW...MVFR CIGS MAY HOLD TOUGH THROUGH THE AFTERNOON. ANY IFR VSBYS
IN THESE SNOW SHOWERS SHOULD QUICKLY IMPROVE TO VFR BY LATE
AFTERNOON.
FOR WATERTOWN EXPECT VFR FLIGHT CONDITIONS FOR MUCH OF THE 18Z TAF
PACKAGE AS THE NOR'EASTER CONTINUES TO PULL EASTWARD...AND LAKE
INFLUENCED SNOW REMAINS TO THE WEST.
TOWARDS LATE EVENING A BAND OF SNOW IS EXPECTED TO FORM OFF GEORGIAN
BAY ON A NORTHWEST FLOW. EXACT PLACEMENT OF THIS BAND THIS FAR OUT
IN TIME IS NOT KNOWN...BUT IT MAY BRIEFLY BRING IFR FLIGHT
CONDITIONS TO THE KROC TERMINAL BETWEEN 5Z AND 8Z BEFORE THE BAND OF
SNOW SHIFTS EASTWARD AS WINDS BACK. FOR NOW WILL CARRY LOW END MVFR
IN THE TAFS FOR THE KROC TERMINAL. THIS BAND OF SNOW IS EXPECTED TO
PRIMARILY EFFECT LOCATIONS EAST OF THE KROC TERMINAL AND SOUTH OF
THE KART TERMINAL OVERNIGHT AND BEGINNING OF TUESDAY.
UPPER LEVEL RIDGE THEN ADVANCES TOWARDS THE REGION TOMORROW WITH ANY
MVFR CIGS IMPROVING TO VFR THROUGH THE EARLY MORNING HOURS.
EXCEPTION WILL BE ACROSS THE EASTERN LAKE ONTARIO REGION WHERE
LEFTOVER MOISTURE FROM THE EASTERN LAKES MAY LOWER CIGS TO MVFR
FOR SEVERAL HOURS.
OUTLOOK...
TUESDAY NIGHT THROUGH WEDNESDAY...MAINLY MVFR IN CIGS. SCATTERED
SNOW SHOWERS EAST AND SOUTHEAST OF LAKE ONTARIO.
WEDNESDAY NIGHT THROUGH FRIDAY...MAINLY VFR.
SATURDAY...DETERIORATING TO IFR/MVFR IN RAIN. LLWS POSSIBLE.
&&
.MARINE...
MODERATE NORTHWEST WINDS WILL CONTINUE TONIGHT THROUGH WEDNESDAY
WITH SMALL CRAFT ADVISORY CONDITIONS ON BOTH LAKES ERIE AND ONTARIO
THROUGH MIDWEEK. THE WINDS WILL SUBSIDE BY THURSDAY AS WARMER AIR
MOVES INTO THE LOWER LAKES AND REDUCES INSTABILITY IN THE MARINE
BOUNDARY LAYER.
&&
.CLIMATE...
ROCHESTER FINALLY BREAKS THE MONTHLY MAXIMUM SNOWFALL RECORD FOR
DECEMBER. AT THE ROCHESTER INTERNATIONAL AIRPORT 0.2 TENTHS OF AN
INCH OF SNOW FELL SUNDAY DECEMBER 26TH. WITH THIS SNOW...A NEW MARK
FOR SNOWIEST DECEMBER ON RECORD HAS BEEN SET. AS OF 100 PM THIS
AFTERNOON...THE TOTAL MONTHLY SNOW TO DATE IN ROCHESTER STANDS AT
46.4 INCHES. THE OLD RECORD OF 46.2 INCHES WAS SET BACK IN
DECEMBER OF 2008. RECORDS FOR SNOWFALL GO BACK TO 1884-1885 FOR
ROCHESTER, NY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY FROM 11 PM THIS EVENING TO 11 AM EST
TUESDAY FOR NYZ004-005.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR
LOZ042>045.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...HITCHCOCK/THOMAS
MARINE...APFFEL/HITCHCOCK
CLIMATE...APFFEL
