000
FXUS61 KBUF 032114
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
414 PM EST WED DEC 3 2008
.SYNOPSIS...
A SHARP COLD FRONT WILL CROSS THE REGION THURSDAY MORNING WITH RAIN
SHOWERS AHEAD OF IT AND SNOW SHOWERS IN ITS WAKE. MIDWINTER COLD
FOLLOW THE FRONT WITH ASSOCIATED LAKE SNOWS FROM THURSDAY NIGHT INTO
EARLY SATURDAY. LOW PRESSURE WILL MOVE IN FROM THE UPPER LAKES
SUNDAY WITH A MORE GENERAL LIGHT SNOWFALL LIKELY SATURDAY NIGHT AND
SUNDAY...THEN RIDGING WILL BRING BRIEF FAIR WEATHER MONDAY BEFORE
ANOTHER LOW APPROACHES TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
A COLD FRONT OVER THE CENTRAL LAKES IS EXPECTED TO MOVE EAST TONIGHT
AND CROSS WESTERN NEW YORK AROUND 12Z THURSDAY AND THEN MOVING EAST
OF CENTRAL NEW YORK BY 18Z AND THEN TO THE NEW ENGLAND COAST BY 00Z
FRIDAY.
A 40 TO 45 KNOT LOW LEVEL JET SURGING AHEAD OF THE FRONT WILL SPREAD
INCREASING LOW LEVEL MOISTURE ACROSS THE AREA TONIGHT. A 160 KNOT
UPPER LEVEL JET TRACKING FROM THE CENTRAL GREATS ACROSS SOUTHERN
ONTARIO WILL ALSO ENHANCE THE LARGE SCALE LIFT. WILL CONTINUE WITH
A WEST TO INCREASE IN POPS OVERNIGHT WITH THE THREAT OF SHOWERS INTO
WESTERN AREAS BY 03Z-05Z AND SPREADING TO THE REST OF THE AREA BY
ARND 07Z-08Z. POPS SHLD INCREASE TO LKLY TO CATEGORICAL RANGE OVER
THE AREA OVERNIGHT. EXPECT MOST OF THE PCPN TO FALL AS RAIN SHOWERS
LATE TONIGHT AS MOST OF THE AREA SHLD REMAIN IN MILD SW FLOW AHEAD
OF THE FRONT BUT THE EXCEPTIONS SHLD BE ACROSS THE HIGHER TERRAIN OF
THE SOUTHERN TIER AND EAST OF LAKE ONTARIO WHERE THE RAIN SHWRS ARE
EXPECTED TO MIX WITH SNOW SHWRS. ACCUMULATIONS SHLD ONLY BE A
COATING TO LESS THAN AN INCH ACROSS THE SOUTHERN TIER HIGH SPOTS
WITH AN INCH OR SO PSBL OVER THE TUG HILL EAST OF LAKE ONTARIO.
12Z THURSDAY...WILL KEEP CATAGORICAL POPS ACROSS THE NORTH COUNTRY
WITH LKLY POPS SW ALNG THE COLD FRONTAL POSITION ACROSS THE SOUTHERN
FINGER LKS AND THE SOUTHERN TIER AND CHC POPS ACROSS THE LOWER
GENESEE VALLEY AND THE NIAGARA FRONTIER AS A RIDGE OF HIGH PRESSURE
WITH DRIER AIR BUILDS NE FROM THE CENTRAL MISSISSIPPI VALLEY.
TMPS SHLD BE WARM ENOUGH IN THE MORNING FOR RAIN/RAIN SNOW MIX
ACROSS LOWER ELEVATIONS WITH MNLY SNOW SHWRS ACROSS THE SOUTHERN
TIER. AMNTS ARE EXPECTED TO BE ON THE LIGHT SIDE GENLY AN INCH OR
LESS WITH LITTLE ACCUMULATION ACROSS LOWER TERRAIN.
AS THE HIGH BUILDS EAST THE PRECIP THREAT SHLD DECREASE IN THE
AFTERNOON TO SLGT CHC RANGE ACROSS MUCH OF THE FINGER LKS AND
NIAGARA FRONTIER BUT WILL KEEP LKLY POPS EAST OF THE LAKES DUE TO
THE COLD WESTERLY UPSLOPE FLOW. TEMPS SHLD START OUT IN THE LOW TO
MID 30S IN THE WEST AND UPPER 30S TO ARND 40 FROM THE FINGER LKS
EAST WITH TEMPS DROPPING DURG THE DAY IN THE WEST AND IN THE
AFTERNOON EAST OF LAKE ONTARIO.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
SOME OF THE COLDEST AIR OF THE SEASON WILL ADVECT ACROSS THE LAKES
THURS NIGHT INTO SATURDAY MORNING WITH 850 MB TEMPS OF -14C TO -16C
BUT HAVE SOME CAVEATS...ESPECIALLY OFF ERIE. THERE WILL REMAIN GOOD
SFC RIDGING AND AIR WILL LIMIT THE LAKE SNOWS OFF LAKE ERIE...AND
WITH FLOW MORE 270-280 THERE WILL BE LITTLE IF ANY MOISTURE PICKED
UP FROM HURON OR THE UPPER LAKES. THERE WILL UNDOUBTEDLY BE SOME
ACTIVITY...PERHAPS ENOUGH FOR AN ADVISORY ON THE CHAUTAUQUA RIDGE
THURSDAY NIGHT AND FRIDAY...BUT CONFIDENCE IN ACCUMULATION IS TOO
LOW FOR A WATCH IN THIS AREA.
CONDITIONS WILL BE MORE FAVORABLE OFF ONTARIO WITH 270-280 FLOW
SETTING UP THURSDAY EVENING AND CONTINUING THROUGH MOST OF FRIDAY
BEFORE BACKING TO 250-260 FRI NIGHT. THE 18Z NAM SHOWS MORE
UNCERTAINTY THAN THE 12Z RUN, WITH LIGHT SNOW STARTING IN WAYNE
COUNTY BEFORE GETTING ORGANIZED, THEN DEVELOPING IT LATE THURSDAY
NIGHT AND BRINGING IT NORTH INTO JEFFERSON COUNTY FRIDAY MORNING.
GIVEN THE RUN TO RUN VARIATION, WE WILL KEEP THE WATCH GOING AND
HOPEFULLY LATER RUNS WILL BE MORE CONSISTENT, AND ALLOW MORE
DEFINITIVE TIMING AND AMOUNTS.
THE WINDS CONTINUE TO BACK FRIDAY NIGHT, WITH A FAVORABLE 240-250
VECTOR FOR BUFFALO FROM ABOUT 04Z TO 14Z SATURDAY...WITH LITTLE
SHEAR AND DECENT MOISTURE FIELDS...SO THERE IS POTENTIAL OF AT LEAST
A FEW INCHES ACROSS THE AREA PREDAWN SATURDAY...BUT THE BAND SHOULD
BE IN THE PROCESS OF WEAKENING AS IT LIFTS NORTH SATURDAY MORNING AS
WINDS BACK FURTHER AND SHEAR INCREASES.
LATER SATURDAY...A CLIPPER MOVES TO LAKE MICHIGAN AND THEN INTO
MICHIGAN...WILL BRING CHANCE OF LIGHT SNOW TO WEST IN THE AFTERNOON
AS IT GETS CLOSER. SFC FLOW WILL BE S-SE THOUGH SO LITTLE
ACCUMULATION IS EXPECTED..
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE CLIPPER LOW WILL MOVE TO WESTERN NEW YORK BY 12Z SUNDAY THEN
REDEVELOP OFF NEW ENGLAND COAST LATER SUNDAY AND SUNDAY NIGHT. WE
SHOULD ALL GET SOME LIGHT SNOW SATURDAY NIGHT AND SUN MORNING...
BUT ACCUMULATIONS LOOK MINOR...COUPLE INCHES AT BEST. THE CHANCE OF
SNOW LOWERS FROM WEST TO EAST IN THE AFTERNOON.
A SHOT OF COLDER AIR FOLLOWS SUNDAY AFTERNOON AND SUNDAY NIGHT WITH
SOME SNOW SHOWERS...BUT NORTHERLY FLOW SHOULD INHIBIT INTENSE LAKE
EFFECT, AND ACCUMULATIONS ALONG THE SOUTH SHORES SHOULD REMAIN BELOW
WARNING AMOUNTS. STRONG RIDGE CROSSES AREA MONDAY FOR A DRY
BEGINNING...THEN NEXT SYSTEM APPROACHES FROM WEST WITH ANOTHER
GENERAL LIGHT SNOW MONDAY NIGHT CHANGING TO RAIN AS THE TEMPERATURES
WARM ON TUESDAY. BOTH THE 12Z NAM AND 12Z ECMWF SHOW AND FRONT
MOVING FURTHER EAST WITH A COASTAL LOW MOVING UP ALONG THE COAST,
AND WE HAVE KEPT LOW CHANCE POPS DUE THE UNCERTAINTY OF TIMING OF
THE END OF THE PRECIPITATION.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
ALL TAF SITES WILL BE VFR THROUGH THE AFTERNOON DUE TO HIGH PRESSURE
MOVING OFF THE CAROLINA COAST. A POTENT LOW LEVEL JET SURGING AHEAD
OF A COLD FRONT MOVING INTO THE CENTRAL LAKES OWILL TRANSPORT
INCREASING LOW LEVEL MOISTURE INTO THE AREA AFTER 04Z. AS SHOWERS
SPREAD EAST ACROSS WESTERN AND CENTRAL NEW YORK...EXPECT CIGS AND
VSBYS TO GRADUALLY LOWER TO MVFR BETWEEN 05Z AND 10Z. LATE
TONIGHT...TEMPERATURES WILL GET COLD ENOUGH TO SUPPORT A MIX OF RAIN
AND SNOW ACROSS THE HIGHER ELEVATIONS OF THE SOUTHERN
TIER...INCLUDING KJHW AFTER ARND 09Z. SOME OCNL LIGHT SNOW IS
POSSIBLE ACROSS THE BUF-IAG-ROC TAF SITES FRM ARND 14Z-15Z WITH MVFR
CIGS CONTINUING. EAST OF LAKE ONTARIO BNDRY LYR TEMPS SHLD KEEP THE
PRECIP AS RAIN FOR KART THROUGH THE END OF THE TAF PERIOD ALTHOUGH
ACROSS THE HIGHER TERRAIN SOUTH OF KART THE PRECIP COULD MIX WITH
SNOW TWD THE END OF THE TAF PERIOD
LLWS WILL ALSO BE A CONCERN FOR AVIATORS TONIGHT AS THE LOW LEVEL
JET TRACKS EAST ACROSS THE AREA SO LLWS HAS BEEN PUT IN THE TAFS FRM
ARND 03Z-09Z.
OUTLOOK...
THURSDAY NIGHT...IFR EAST OF THE LAKES IN LAKE EFFECT SNOW.
FRIDAY...IFR IN LAKE SNOWS EAST OF THE LAKES..VFR
ELSEWHERE.
SATURDAY...IFR IN LK SNOWS NE OF THE LAKES.
SATURDAY NIGHT...IFR/MVFR IN WIDESPREAD SNOW SHOWERS.
SUNDAY...MVFR/IFR IN SNOW SHWRS WITH HEAVIER LK SNOWS SE OF THE LKS.
MONDAY...MVFR PSBL IN SOME LINGERING LK SNOWS SE OF LK ONTARIO.
&&
.MARINE...
LOOK FOR FRESH SOUTH TO SOUTHWEST WINDS WITH GUSTS INCREASING TO
NEAR GALE FORCE LATER TONIGHT JUST AHEAD OF THE COLD FRONT. WINDS
WILL THEN SHIFT ABRUPTLY TO THE WEST AND NORTHWEST IN THE WAKE OF
THE FRONT THURSDAY WITH BRISK WESTERLIES CONTINUING INTO FRIDAY.
WIND SPEEDS WILL BE SUFFICIENT FOR SMALL CRAFT ADVISORIES OFF LAKE
ERIE AND THE EAST END OF LAKE ONTARIO THROUGH AT LEAST FRIDAY. GALE
WARNINGS ARE IN EFFECT FOR GUSTS TONIGHT.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WATCH FROM THURSDAY EVENING THROUGH SATURDAY
MORNING FOR NYZ006>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR LEZ040-041.
GALE WARNING FROM 1 AM TO 8 AM EST THURSDAY FOR
LOZ045-063>065.
SMALL CRAFT ADVISORY FROM 3 AM TO 5 PM EST THURSDAY FOR
LOZ042>044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR LOZ045.
&&
$$
SYNOPSIS...APB/SFM
NEAR TERM...JJP
SHORT TERM...APB/SFM
LONG TERM...APB/SFM
AVIATION...APB/JJP
MARINE...APB
