FXUS61 KBUF 292051
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
351 PM EST SUN NOV 29 2009
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE EASTERN GREAT LAKES AND DOWN THE
SAINT LAWRENCE VALLEY TONIGHT. THIS WILL DRAW A COLD FRONT ACROSS
NEW YORK STATE BETWEEN MIDNIGHT AND DAYBREAK...AND BRING COLDER
TEMPERATURES FOR MONDAY. RAIN SHOWERS ALONG THE FRONT WILL MIX WITH
AND CHANGE TO SNOW SHOWERS FROM MID MORNING THROUGH THE AFTERNOON.
AREAS OF LAKE EFFECT SNOW WILL SET UP EAST OF THE LAKES ON TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
SURFACE RIDGE SHIFTING EAST OF THE AREA THIS AFTERNOON AND PROVIDING
A VERY FINE LATE AUTUMN DAY FOR WESTERN AND CENTRAL NEW YORK.
SUNSHINE FILTERED THROUGH HIGH CLOUDINESS FOR MUCH OF THE AREA WITH
SOME LINGERING STRATUS PUSHING THROUGH THE NORTH COUNTRY. DOWNSLOPE
FLOW ON THE BACK OF THE RETREATING HIGH HAS ALLOWED TEMPERATURES
TO PEAK MOSTLY IN THE LOWER TO MID 50S WITH UPPER 40S UNDERNEATH
THE STRATUS LAYER...WITH EVEN A FEW CENTRAL GENESEE VALLEY
LOCATIONS IN THE UPPER 50S. THESE READINGS ARE SOME 10 TO 15
DEGREES ABOVE NORMAL.
BIG CHANGES COMING TONIGHT.
WATER VAPOR IMAGERY THIS AFTERNOON SHOWING A STRONG MID LEVEL SHORT
WAVE DIVING DOWN THROUGH THE UPPER MIDWEST/WESTERN GREAT LAKES.
ASSOCIATED SURFACE WAVE PUSHING INTO SOUTHWESTERN ONTARIO WITH A
SHARP COLD FRONT WORKING THROUGH SOUTHEAST LOWER MICHIGAN AND
NORTHERN INDIANA. REGIONAL RADARS UPSTREAM SHOWING FAIRLY
WIDESPREAD SHOWER ACTIVITY BREAKING OUT IN AREA OF INCREASING
FRONTOGENETIC FORCING ALONG THE TIGHTENING BAROCLINIC ZONE
COMBINED WITH UPPER LEVEL SUPPORT FROM A 110 KNOT PLUS UPPER JET
CORE WORKING ACROSS MICHIGAN AND SOUTHERN ONTARIO.
THE UPSTREAM SHOWER ACTIVITY WILL DEVELOP INTO THE AREA AFTER 6 PM
AND BECOMING INCREASING WIDESPREAD THROUGH THE EVENING AND INTO
EARLY TONIGHT AS THE SURFACE LOW TRACKS INTO THE SAINT LAWRENCE
VALLEY AND THE COLD FRONT PUSHES ACROSS THE AREA IN THE 06Z TO 09Z
TIME FRAME. LOW LEVEL FORCING AND UPPER SUPPORT DIMINISHES BEHIND
THE COLD FRONT AND WE SHOULD SEE THE PRECIPITATION WANE LATE TONIGHT
AND MONDAY. TEMPERATURES WILL BE AT THEIR WARMEST AHEAD OF THE
FRONT...THEN WILL FALL OFF IN THE WAKE OF THE FRONT AS A MODEST
LOW LEVEL COLD AIR ADVECTION REGIME TAKES OVER.
850 MB TEMPERATURES DROP INTO THE -6C TO -9C RANGE DURING THE DAY
MONDAY AND THIS WILL PROBABLY GET SOME LAKE ENHANCEMENT/LAKE EFFECT
ACTIVITY GOING SOUTH AND SOUTHEAST OF THE LAKES. HOWEVER...MOISTURE
IS RATHER UNIMPRESSIVE AND THERE WILL BE SOME LOW LEVEL RIDGING
TAKING PLACE BEHIND THE DEPARTING SURFACE LOW WHICH WILL PRODUCE
AN UNFAVORABLE ANTICYCLONIC FLOW FOR A PERIOD...LIMITING THE
POTENTIAL FOR ACCUMULATIONS. CONDITIONS FOR ACCUMULATING LAKE
EFFECT SNOWS SOUTH AND SOUTHEAST OF THE LAKES COULD BECOME A BIT
MORE FAVORABLE MONDAY NIGHT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
TEMPERATURES FALL TO THE MID 20S TO LOWER 30S MONDAY NIGHT. A SFC
TROUGH MOVING EAST FROM THE CENTRAL LAKES WILL BRING CHC SNOW
SHOWERS WITH LAKE SNOWS EXPECTED TO THE EAST OF THE LAKES...POPS IN
THE CAT RANGE ALONG THE CHAUTAUQUA RIDGE WITH ACCUMS GENERALLY IN
THE 2-3 INCH RANGE WITH A COUPLE OF INCHES POSSIBLE EAST OF LK
ONTARIO.
TUESDAY, THE SFC TROUGH MOVES EAST ACROSS THE AREA IN THE MORNING.
WINDS WILL BE SW ENOUGH AHEAD OF THE TROUGH IN THE MORNING TO BRING
SOME LK ENHANCED SNOW CLOSE TO THE BUF METRO AREA TUESDAY MORNING
AND THEN IN THE AFTERNOON WINDS SHOULD SHIFT NW AGAIN BEHIND THE
TROUGH AND PUSH MOST OF THE PRECIP SOUTH AGAIN. SNOW SHWRS WILL ALSO
BE LIKELY EAST OF LK ONTARIO IN THE MORNING WITH A MIX IN THE
AFTERNOON OVER LOWER ELEVATIONS. WILL CONTINUE CHC POPS TUESDAY
EVENING ACROSS PORTIONS OF THE NORTH COUNTY WITH LINGERING LK EFFECT
THERE. ELSEWHERE UPPER RIDGING...SOUTHWESTERLY WINDS AND WARMING
WILL BRING AN END TO THE LAKE EFFECT AND BRING PARTIAL CLEARING
TUESDAY NIGHT. IT WILL STILL BE QUITE COLD WITH OVERNIGHT LOWS IN
THE MID 20S OVER MOST OF THE FORECAST AREA WITH SOME LOWER 30S ALONG
THE LAKE ERIE SHORELINE AREAS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A PLAINS CLOSED UPPER LOW WILL OPEN AND LIFT ALONG THE WESTERN
APPALACHIANS DURING WEDNESDAY AFTERNOON AND SPREAD PRECIP INTO THE
FORECAST AREA DURING WEDNESDAY NIGHT. 12Z GFS AND ECMWF ARE BRINGING
PRECIP IN FROM THE SOUTH FASTER THAN THE NAM...WHICH IS MUCH SLOWER
ON THE PLAINS CLOSED LOW. WILL CONTINUE TO TREND WITH THE GFS/ECMWF
SOLUTION WHICH SHOWS A MIXED PRECIP EVENT IN STORE FOR THURSDAY
MORNING AS WARMER AIR ALONG THE EASTERN AND NORTHERN QUADRANTS OF
THE LOW WILL PRODUCE RAIN...WARMER AIR ALOFT AND COLDER AIR NEAR THE
SURFACE WILL RESULT IN SOME FREEZING RAIN CHANCE OVER THE BLACK
RIVER VALLEY...AND COLDER AIR AT SURFACE AND ALOFT WEST OF THE
GENESEE RIVER WILL YIELD ALL SNOW OR A SNOW/SLEET MIX. THE LOW WILL
BE OVER THE SAINT LAWRENCE VALLEY LATE ON THURSDAY AND THE TRAILING
MID LEVEL DEFORMATION ZONE WILL BE FROM WESTERN TO NORTHERN NEW YORK
AND COULD BRING AN ACCUMULATING SYNOPTIC SNOW AS ECMWF QPF RANGES
NEAR THREE QUARTERS OF AN INCH /LIQUID/ WHICH COULD BRING SEVERAL
INCHES OF SNOW.
AS THE SURFACE LOW LIFTS NORTHWARD INTO WESTERN QUEBEC ON THURSDAY
NIGHT...THE FLOW ON THE WESTERN SIDE OF THE LOW WILL DRAW MUCH
COLDER AIR INTO NEW YORK STATE DURING THURSDAY NIGHT...DEEPENING AND
GETTING COLDER ON FRIDAY. THIS COULD SPELL THE BEGINNING OF A WELL
DEVELOPED LAKE EFFECT SNOW EVENT WITH 850MB TEMPS FALLING TO A RANGE
FROM -10C TO -12C BY LATE FRIDAY MORNING.
THE WEEKEND WILL SEE A MORE ZONAL FLOW DEVELOPING BUT 850MB TEMPS
WILL HOVER AT OR BELOW ZERO THROUGH THE WEEKEND. CHANCE POPS EACH
DAY WILL OFFER SOME NIGHTTIME SNOW SHOWERS AND DAYTIME RAIN SHOWERS
OR A RAIN/SNOW MIX AT HIGHER ELEVATIONS.
COLDER TEMPS ARE EXPECTED THROUGH THE REST OF THE WEEK WITH LOWS IN
THE MID TO UPPER 20S AND HIGHS ONLY IN THE MID TO UPPER 30S. THE
WEEKEND MAY SEE A MODERATING TREND WITH HIGHS IN THE UPPER 30S TO
NEAR 40 ON SATURDAY AND TO THE LOWER 40S ON SUNDAY.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
BAND OF 3K TO 4K FOOT CLOUDINESS FROM LAKE ONTARIO INTO NORTHEAST
NEW YORK WILL IMPACT THE KART TERMINAL THIS AFTERNOON.
OTHERWISE...GOOD VFR FLYING WILL BE THE RULE THIS AFTERNOON.
CLOUDS WILL THICKEN UP THIS EVENING WITH AN APPROACHING GREAT LAKES
COLD FRONT. CONDITIONS WILL DROP TO MVFR WITH RAIN SHOWERS...
PRIMARILY AFTER 03Z. SOME LOCAL IFR CONDITIONS ARE ALSO POSSIBLE
ESPECIALLY ALONG THE SOUTHERN TIER.
OUTLOOK...
MONDAY...MVFR/IFR. CHANCE RAIN/SNOW SHOWERS.
MONDAY NIGHT...MVFR WITH SCATTERED SHOW SHOWERS. LOCAL IFR/LIFR IN
LAKE EFFECT SNOW EAST OF LAKES ERIE AND ONTARIO.
TUESDAY...VFR/MVFR. CHANCE RAIN/SNOW SHOWERS.
WEDNESDAY...VFR.
THURSDAY...MVFR/IFR. CHANCE OF RAIN AND SNOW.
FRIDAY...MVFR. CHANCE OF SNOW. LOCAL IFR/LIFR IN LAKE EFFECT SNOW
EAST OF LAKES ERIE AND ONTARIO.
&&
.MARINE...
NO MARINE HEADLINES AT THIS TIME AS WINDS AND WAVES WILL BE BELOW
SMALL CRAFT ADVISORY RANGE BUT THEY WILL BE NEEDED ON MONDAY ON
LAKE ERIE AS SW WINDS INCREASE AHEAD OF THE COLD FRONT AND THEN
SHIFT TO THE NW BEHIND THE FRONT LATER TONIGHT. ON LK ONTARIO SMALL
CRAFT ADVISORIES WILL LIKELY BE NEEDED AS NW WINDS INCREASE BEHIND
THE FRONT ON MONDAY AND CONTINUE MONDAY NIGHT. WINDS BACK TO
SOUTHWEST AND INCREASE ON TUESDAY...WITH THE POTENTIAL FOR SMALL
CRAFT CRITERIA WAVES TUESDAY AFTERNOON AND NIGHT.
&&
.CLIMATE...
STILL NO MEASURABLE SNOW SO FAR THIS SEASON OVER MOST OF WESTERN NEW
YORK. WE ARE ALREADY OVER THREE WEEKS LATE (NORMAL DATES ARE NOV 7
FOR BUFFALO AND NOV 8 FOR ROCHESTER). WE WILL AT LEAST GET TO MONDAY
(30TH) AND IF SO...WILL BE THE LATEST IN 63 YEARS (1946) AT
BUFFALO...AND LATEST IN 46 YEARS (1963) AT ROCHESTER. THE ALL TIME
RECORD LATEST DATES FOR FIRST MEASURABLE SNOW ARE DEC 3 1899 AT
BUFFALO AND DEC 10 1948 AT ROCHESTER.
IN ADDITION, ITS BEEN A LONG TIME SINCE EITHER BUFFALO OR ROCHESTER
LAST SAW MEASURABLE SNOW. THROUGH TODAY NOV 29...BUFFALO WILL HAVE GONE
236 DAYS WITHOUT MEASURABLE SNOW, OR SINCE APRIL 7, 2009. THIS IS
THE 4TH LONGEST STRETCH IN 125 YEARS OF RECORDS. THE RECORD IS 277
DAYS SET BACK IN 1946. ROCHESTER IS ALSO AT 236 DAYS WITHOUT
MEASURABLE SNOW, OR THE 3RD LONGEST STRETCH THERE. THE RECORD IS
260 DAYS SET BACK IN 1952.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...TMA
MARINE...WCH
CLIMATE...TMA
