FXUS61 KBUF 300456
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1156 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/...
MOISTURE CHANNEL IMAGERY SHOWING A WELL DEFINED MID LEVEL SHORTWAVE
CROSSING THE CENTRAL LAKES THIS EVENING WITH SOUTHERN STREAM PHASING
EVIDENT...ALLOWING A STREAM OF AMPLE MOISTURE TO BE DRAWN UP INTO
THE LOWER LAKES REGION. LARGE SCALE FORCING FOR ASCENT IN ADVANCE OF
THE MID LEVEL TROUGH WILL COMBINE WITH UPPER LEVEL DIFFLUENCE WITHIN
A COUPLED JET STRUCTURE ALOFT TO PRODUCE DEEP LAYER ASCENT OVER THE
CWA TONIGHT. HAVE UPDATED FORECAST TO INCREASE TIMING OF THE ONSET
OF RAIN AND ALSO CHANGE WORDING TO PERIODS OF RAIN AND INCREASE QPF
INTO THE QUARTER TO HALF INCH RANGE.
RAIN WILL QUICKLY END FROM WEST TO EAST AROUND 12Z MONDAY AS THE
UPPER LEVEL FORCING AND SURFACE COLD FRONT MOVE QUICKLY EAST. THIS
WILL LEAVE MOIST NORTHWEST FLOW IN ITS WAKE...WHICH WILL LIKELY
PRODUCE A FEW LINGERING SHOWERS ACROSS THE HIGHER TERRAIN OF THE
WESTERN SOUTHERN TIER AND ALSO THE TUG HILL/WESTERN ADIRONDACKS
THROUGH MONDAY MORNING DUE TO UPSLOPING. WILL KEEP LIKELY POPS GOING
IN THESE AREAS. BY THEN...COLDER AIR FILTERING INTO THE REGION IN
THE WAKE OF THE COLD FRONT WILL ALLOW SOME WET SNOW TO MIX IN ACROSS
HIGHER TERRAIN...BUT NO ACCUMULATION IS EXPECTED. OUTSIDE OF THIS
UPSLOPE ACTIVITY...HAVE SPED UP THE ENDING TIME OF PRECIP ELSEWHERE.
PRECIP SHOULD END ACROSS THE LOWER ELEVATIONS BEFORE THE COLUMN IS
COLD ENOUGH FOR SNOW.
STEADY MODERATE COLD AIR ADVECTION WILL DROP 850MB TEMPS DOWN TO
AROUND -8C BY MONDAY EVENING. DESPITE THE DEEPENING COLD AIR...A
RIDGE BUILDING INTO THE LOWER LAKES WILL INITIALLY PREVENT ANY LAKE
EFFECT ACTIVITY FROM DEVELOPING. HAVE REMOVED POPS FROM TUESDAY
AFTERNOON GIVEN THIS UNFAVORABLE ENVIRONMENT FOR A LAKE RESPONSE.
CONDITIONS BECOME MORE FAVORABLE LATER MONDAY EVENING...AS DISCUSSED
IN THE SHORT TERM SECTION.
OVERCAST SKIES IN THE MORNING WILL GIVE WAY TO SOME PARTIAL CLEARING
DURING THE AFTERNOON ACROSS THE LOWER ELEVATIONS OF THE NIAGARA
FRONTIER AND ALONG THE SOUTH SHORE OF LAKE ONTARIO. EXPECT THE
WESTERN SOUTHERN TIER TO REMAIN CLOUDY THROUGH THE AFTERNOON WITH
MOIST UPSLOPE FLOW CONTINUING. EXPECT HIGHS TO OCCUR EARLY IN THE
DAY WITH TEMPERATURES FALLING BY LATE AFTERNOON IN RESPONSE TO
ONGOING MODERATE COLD AIR ADVECTION.
&&
.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 SPLIT FLOW OVER THE EASTERN HALF OF COUNTRY WEDNESDAY MORNING WILL
PHASE INTO A FAIRLY DEEP LONG WAVE TROUGH OVER THE GREAT LAKES
REGION BY FRIDAY. THIS WILL RESULT IN A CHANGE TO COLDER...MORE
SEASONABLE CONDITIONS THAT WILL PERSIST THROUGH THE WEEKEND. THIS
WILL LIKELY LEAD TO MORE SNOW AS WELL...AND POSSIBLY SOME
SIGNIFICANT LAKE EFFECT ACTIVITY.
THE CLOSED LOW OVER THE TEXAS/LOWER MISSISSIPPI VALLEY WEDNESDAY IS
EXPECTED TO OPEN UP BY WEDNESDAY EVENING...WITH A SFC WAVE DEEPENING
AS IT LIFTS UP ALONG THE SPINE OF THE APPALACHIANS. THIS WILL SEND A
SURGE OF MOISTURE UP ACROSS THE MID ATLANTIC STATES TO OUR REGION...
ALONG WITH RELATIVELY MILD AIR. HAVE RAISED SFC TEMPS BY SOME 3 TO 6
DEG F FOR WEDNESDAY NIGHT AS THE GEFS...OPERATIONAL GFS AND ECWMF
BRING THE SFC LOW UP ACROSS PENNSYLVANIA. WHILE THE ECMWF IS SOME
100 MILES 'SLOWER' THAN THE GEFS AND OPERATIONAL GFS...IT IS ALSO
FAVORING A WARM ADVECTION PATTERN ALOFT. THE GEFS MEAN H85 TEMP OVER
THE FINGER LAKES REGION AT 06Z THURS IS AROND ZERO C WITH FAIRLY
STRONG WAA EXPECTED FROM THAT POINT INTO THE EARLY DAYLIGHT HOURS OF
THURSDAY.
AS A RESULT...HAVE BACKED OFF ON THE FROZEN/FREEZING PCPN FOR
WEDNESDAY NIGHT AND HAVE SIMPLY MADE THE P-TYPE AS RAIN. POPS FOR
WEDN NIGHT HAVE ALSO BEEN RAISED A LITTLE TO HIGH LIKELY (FROM CHC).
DURING THE COURSE OF THURSDAY AS THE TWO MAIN JETS PHASE OVER THE
OHIO VALLEY...A SUB 990MB LOW WILL CONTINUE TO LIFT AND DEEPEN ACROS
NEW ENGLAND. COLDER AIR ON ITS BACKSIDE WILL POUR ACROSS OUR REGION
AND CHANGE THE RAIN TO SNOW...WITH BOTH THE ECMWF AND GEFS
SUGGESTING A PROLONGED DEFORMATION ZONE DRAGGING ACROSS THE BULK OF
THE REGION. THIS 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 WOULD TRASNLATE INTO SEVERAL INCHES OF SNOW.
AS THE SURFACE LOW LIFTS NORTHWARD ACROSS 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 /06Z MONDAY THROUGH FRIDAY/...
REGIONAL RADAR IMAGERY SHOWING THE FIRST AREA OF RAIN MOVING INTO
EASTERN NY AND THE ADIRONDACKS...WITH ANOTHER SOLID AREA OF RAIN
MOVING INTO WESTERN NY. THE EASTERN LAKE ONTARIO REGION WILL SEE A
BREAK IN THE RAIN THROUGH ABOUT 08Z...OTHERWISE EXPECT WIDESPREAD
RAIN THROUGH ABOUT 12Z ACROSS MUCH OF THE AREA. THE RAIN WILL BE
ACCOMPANIED BY WIDESPREAD MVFR CIGS AND AREAS OF MVFR VSBY...WITH
IFR CIGS ACROSS THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER.
RAIN WILL END QUICKLY AFTER 12Z MONDAY ACROSS LOWER ELEVATIONS. IN
THE WESTERN SOUTHERN TIER AND EAST OF LAKE ONTARIO UPSLOPE FLOW INTO
THE HIGHER TERRAIN MAY CONTINUE TO SQUEEZE OUT SOME LIGHT PRECIP...
WITH COOLING TEMPERATURES ALOFT ALLOWING SOME OF THIS TO MIX WITH
WET SNOW. THE ONLY TERMINAL THIS MAY IMPACT WOULD BE KJHW. OTHERWISE
EXPECT RAIN TO END BEFORE THE COLUMN BECOMES COLD ENOUGH TO SUPPORT
SNOW AT THE OTHER TAF SITES.
MVFR CIGS WILL CONTINUE THROUGH MONDAY MORNING BEFORE SCATTERING OUT
DURING THE AFTERNOON ACROSS LOWER ELEVATIONS. EXPECT UPSLOPE FLOW TO
ALLOW MVFR CIGS TO PERSIST THROUGH THE AFTERNOON ACROSS THE HIGHER
TERRAIN OF THE SOUTHERN TIER.
OUTLOOK...
MONDAY NIGHT...MVFR WITH SCATTERED SNOW SHOWERS. LOCAL IFR/LIFR IN
LAKE EFFECT SNOW EAST OF LAKE ERIE.
TUESDAY...VFR/MVFR WITH CHANCE RAIN/SNOW SHOWERS. LOCAL IFR/LIFR IN
LAKE EFFECT SNOW/RAIN THE MORNING EAST OF LAKES ERIE AND ONTARIO.
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...HITCHCOCK
SHORT TERM...WCH
LONG TERM...RSH/WCH
AVIATION...HITCHCOCK
MARINE...WCH
CLIMATE...TMA
