FXUS61 KBUF 011050
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
550 AM EST TUE DEC 1 2009
.SYNOPSIS...
A FLOW OF COLD AIR WILL CONTINUE ACROSS THE RELATIVELY MILD WATERS
OF THE LOWER GREAT LAKES TODAY WHILE A SURFACE TROUGH MOVES QUICKLY
FROM GEORGIAN BAY TO NEW ENGLAND. A RIDGE OF HIGH PRESSURE WILL
FOLLOW AND MOVE OFF THE EAST COAST TONIGHT. THIS WILL PRODUCE DRY
WEATHER ACROSS THE REGION TONIGHT AND MUCH OF WEDNESDAY ALONG WITH A
WARMING TREND. LOW PRESSURE EXPECTED TO GAIN STRENGTH OVER THE GULF
STATES IS FORECAST TO MOVE NORTHWARD AND BRING WIDESPREAD RAIN TO
THE AREA WEDNESDAY NIGHT AND THURSDAY. THE POTENTIAL EXISTS FOR
SIGNIFICANT LAKE EFFECT SNOWS OFF BOTH LAKE ERIE AND LAKE ONTARIO
FROM THURSDAY NIGHT INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
A QUICK UPDATE WAS SENT TO REMOVE THE LAKE EFFECT SNOW ADVISORY
FROM NIAGARA COUNTY. THE SNOW HAS MOVED TO THE SOUTH.
EARLIER DISCUSSION BELOW...
BAND OF LAKE ENHANCED SNOW OFF LAKE ERIE EXTENDING NE ACROSS THE
BUF METRO AREA AND EXTENDING NE TO WESTERN MONROE COUNTY. AS OF
4AM 3.2 INCHES OF SNOW REPORTED AT BUFFALO AIRPORT WEATHER
STATION. EXPECT ANOTHER 2-3 INCHES BEFORE IT SHIFTS SOUTH AND
TAPERS OF TO A CHANCE OF RAIN AND SNOW SHOWERS LATER THIS
AFTERNOON OVER THE SKI COUNTRY. STILL EXPECTING UP TO ARND 6
INCHES TOTAL IN THE BUFFALO AREA WITH THE HIGEST AMNTS EAST OF THE
CITY. THIS WILL IMPACT MORNING COMMUTES.
THE H5 TROUGH OVER THE LOWER LAKES WILL MOVE EAST ACROSS THE REGION
THIS MORNING ALONG WITH ITS EMBEDDED SHORTWAVE. THE CYCLONIC FLOW
ALONG WITH H85 TEMPS OF -6 TO -8C HAS ENCOURAGED THE LAKE INDUCED
CONVECTION. THE MESOSCALE CONVECTION WILL BE ENHANCED BY THE PASSAGE
OF THE ABV SHORTWAVE AS WELL AS THE DEEP CYCLONIC FLOW.
IN TERMS OF THE MESOSCALE PARAMETERS...A FAIRLY WELL ALIGNED
SOUTHWESTERLY FLOW HAS BECOME ESTABLISHED OVER LAKE ERIE AS THE
SYNOPTIC SHORTWAVE MOVES THROUGH THE AREA. A DEEP MOISTURE FIELD
WITH A LAKE DELTA T OF 13-15 DEG HAS ALLOW THE WELL DEFINED LAKE
BAND TO DEVELOP OVER THE EASTERN END OF LK ERIE. LAKE INDUCED CAPES
OF 300-500 J/KG WILL BE IN PLACE THIS MORNING WITH LAKE INDUCED
EQUILIBRIUM LEVELS RISING TO MORE THAN 10K FT. THE COMBINATION OF
THE RELATIVELY HIGH EQUILIBRIUM LEVELS AND -10C HGT OF AT LEAST 6K
FT HAS ALSO BROUGHT THE THUNDERSNOW EARLIER THIS MORNING AS WAS
PREDICTED BY THE PREVIOUS SHIFT. CONTINUED TO CARRY THUNDER AND
LIGHTNING WITHIN THE BAND EARLY THIS MRNG.
RATES OF A HALF TO ONE INCH PER HOUR HAS EXTENDED INLAND ACROSS
NORTHERN ERIE COUNTY TO NORTHERN GENESEE DURG THE PRE DAWN HOURS.
THE OPERATIONAL NAM AND SEVERAL LOCALLY RUN 6KM MESOSCALE MODELS
HAVE NAILED THE NIAGARA FRONTIER FOR THE EVENT THIS MORNING. TOTAL
AMOUNTS OF 2 TO 6 INCHES WILL BE FORECAST FOR NORTHERN
ERIE...WESTERN GENESEE...SOUTHERN ERIE AND PARTS OF CHAUTAUQUA
COUNTY. LESSER AMOUNTS WILL BE FOUND FURTHER EAST AND NORTH.
THE BAND WILL BE IN THE VICINITY OF BUFFALO AND WESTERN GENESEE
COUNTY THROUGH 12Z...THEN AS WINDS VEER TO THE WEST-NORTHWEST...THE
ACTIVITY WILL SETTLE WELL SOUTH OF BUFFALO. HIGHER SHEAR WILL BE
INTRODUCED AS WELL DURING THE COURSE OF THE MORNING AND MIDDAY...SO
AS THE ACTIVITY DROPS SOUTH IT WILL BECOME MORE UNORGANIZED. WARM
ADVECTION WILL ALSO DROP THE INVERSION AND SQUASH THE RESIDUAL LAKE
EFFECT SNOWS DURING THE AFTERNOON AND EVENING.
OFF LK ONTARIO...THE INITIAL SNOWS DURING THE MORNING AND MIDDAY
WILL BE SYNOPTIC IN NATURE. THIS WILL CHANGE BY MIDDAY AS THE COLD
AIR BECOMES DEEP ENOUGH AND THE WESTERLY FLOW BECOMES BETTER ALIGNED
TO SUPPORT PURE LAKE EFFECT OVER THE TUG AREA FOR MUCH OF THE MIDDAY
AND AFTERNOON. SNOW ACCUMS EAST OF LK ONTARIO WILL GENERALLY RANGE
FROM 2 TO 4 INCHES ON TUESDAY...WITH ADDITIONAL MINOR ACCUMS
POSSIBLE TUESDAY EVENING. SLIGHTLY HIGHER FORECAST AMOUNTS WOULD
NECESSITATE A LAKE EFFECT SNOW ADVISORY...SO THIS WILL BE CLOSELY
MONITORED BY LATER SHIFTS. EL HEIGHTS WILL BE ACCOMPANIED BY A
-10C LEVEL OF ABOUT 5K FT.
THE LARGEST IMPACT FROM THE LAKE EFFECT OF THE NEXT 24 HOURS SHOULD
BE FELT IN THE BUFFALO METRO AREA WHERE SNOWFALL RATES OF A HALF TO
ONE INCH AN HOUR WILL COME DURING THE RUSH HOUR...ESPECIALLY THE
FIRST HALF OF IT. MOTORISTS WILL NEED TO BE PREPARED AND SHOULD PLAN
ACCORDINGLY FOR A SLOWER AND POTENTIALLY A MUCH CHALLENGING COMMUTE.
LAKE EFFECT/ENHANCED SNOWS WILL BE WINDING DOWN EAST OF THE LAKES
EARLY TUESDAY NIGHT AS RIDGING...DRIER AIR AND WARM AIR ADVECTION
WORK INTO THE AREA HELPING TO LOWER INVERSION HEIGHTS. WE COULD SEE
A LINGERING...BUT WEAKENING LAKE BAND EAST OF LAKE ONTARIO BEFORE
MIDNIGHT...BUT ANY ADDITIONAL ACCUMULATIONS SHOULD BE LIMITED.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
A LONG WAVE RIDGE ALOFT CRESTING ACROSS OUR REGION AND A SURFACE
HIGH OFF THE MID ATLANTIC COAST AT THE BEGINNING OF THIS PERIOD WILL
MAKE FOR A VERY NICE DAY WEDNESDAY. PLENTY OF SUNSHINE IN MOST AREAS
FOR THE FIRST HALF OF THE DAY ALONG WITH 850 MB TEMPERATURES AROUND
4C AND A DOWNSLOPE FLOW SHOULD EASILY LEAD TO HIGHS IN THE UPPER 40S
OVER HIGHER ELEVATIONS AND LOWER 50S IN THE LAKE PLAIN. CLOUDS WILL
BE ON THE INCREASE DURING THE AFTERNOON AS A DEEPENING LOW PRESSURE
SYSTEM APPROACHES FROM THE TENNESSEE VALLEY. THERE MAY BE RAIN
ACROSS THE SOUTHERN TIER LATE IN THE DAY.
A WIDESPREAD RAIN WILL OVERSPREAD THE ENTIRE REGION WEDNESDAY NIGHT
WITH A POTENTIAL FOR OVER AN INCH AS THE DEEPENING LOW MOVES NORTH
TO EASTERN NEW YORK. THERE MAY BE SOME LOCAL FLOOD PROBLEMS.
THE DEEP SURFACE LOW WILL LIFT QUICKLY INTO NORTHERN NEW ENGLAND BY
THE END OF THE DAY THURSDAY. DRY SLOT WORKING INTO THE AREA BEHIND
THIS SYSTEM WILL HELP TO DIMINISH THE PRECIPITATION DURING THE DAY
THURSDAY. LAKE EFFECT/ENHANCED SNOWS COULD BEGIN AS EARLY AS MID TO
LATE AFTERNOON AS 850 MB TEMPERATURES DROP TO NEAR -6C. MUCH MORE
SIGNIFICANT LAKE SNOWS WILL DEVELOP DURING THE EXTENDED PORTION OF
THE FORECAST PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE POTENTIAL EXISTS FOR THE FIRST SIGNIFICANT LAKE EFFECT SNOWS OFF
BOTH LAKES DURING THIS PERIOD.
LOW PRESSURE WILL CONTINUE TO PUSH AWAY FROM THE AREA THURSDAY NIGHT
AS A SURFACE TROUGH EDGES DOWN TOWARD THE AREA FROM ONTARIO. HIGH
PRESSURE ANCHORED WELL SOUTH OF THE AREA WILL RESULT IN THE
DEVELOPMENT OF A WELL ALIGNED WEST TO SOUTHWEST FLOW ACROSS THE
LOWER LAKES THURSDAY NIGHT AND CONTINUING RIGHT INTO THE EARLY PART
OF THE WEEKEND. LAKE SNOW DETAILS MUCH TOO EARLY TO PINPOINT THIS
FAR OUT...BUT MODEL TRENDS HAVE US GROWING IN CONFIDENCE THAT
SIGNIFICANT LAKE SNOWS WILL BE POSSIBLE THURSDAY NIGHT THROUGH
SATURDAY OFF BOTH LAKE ERIE AND EAST OF LAKE ONTARIO...INCLUDING
THE BUFFALO METRO AREA AND WATERTOWN AS 850 MB TEMPERATURES DROP
TO BELOW -10C. WILL TREND EXTENDED FORECAST GRIDS TOWARD THIS AND
WILL MENTION THE POTENTIAL IN THE HWO.
SURFACE TROUGH LOOKS TO MOVE THROUGH THE AREA BY SUNDAY SHIFTING
THE FLOW MORE NORTHWEST AND PUSHING LAKE BAND INTO THE MORE
FAVORABLE AREA SOUTH OF BUFFALO AND SOUTHEAST OF LAKE ONTARIO.
BACKING FLOW COULD BRING LAKE BANDS BACK NORTHWARD BY EARLY NEXT
WEEK.
COLDER TEMPERATURES EXPECTED THROUGH THE PERIOD WITH HIGHS MAINLY
IN THE 30S AND LOWS GENERALLY IN THE 20S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
MAIN CONCERN FOR THIS TAF CYCLE REVOLVES AROUND LAKE EFFECT PRECIP
POTENTIAL. FOLLOWING A RIDGE AXIS THIS EVENING...FLOW WILL BECOME
BETTER ALIGNED OUT OF THE SOUTHWEST. THE AIRMASS IS STILL COLD
ENOUGH INITIALLY TO SUPPORT A LAKE RESPONSE...AND MARGINALLY COLD
ENOUGH TO SUPPORT WET SNOW AS THE PRECIP TYPE. MESOSCALE MODELS HAVE
BEEN CONSISTENT THE PAST FEW RUNS IN DEVELOPING THIS BAND. REGIONAL
RADAR IMAGERY SHOWS SOME LIGHT LAKE ENHANCED SNOW SHOWERS OVER LAKE
ERIE NW OF DKK WITH OTHER ACTIVITY ONSHORE ACROSS THE SOUTHERN TIER.
EXPECT THE BAND TO BECOME BETTER ORGANIZED AT THE NORTHEAST END OF
LAKE ERIE AND EXTEND INTO KBUF VCNTY DURING THE EARLY MORNING HOURS.
STILL SOME UNCERTAINTY WITH REGARDS TO PRECIP TYPE...SO HAVE GONE
WITH A PREDOMINANT RA/SN MIX AND TEMPO MODERATE SNOW WITH THE
SUGGESTION THAT HEAVIER PRECIP ELEMENTS WILL OFFER THE BEST CHANCE
OF ALL SNOW. IF PRECIP TYPE GOES TO ALL SNOW...VSBY MAY APPROACH
AIRFIELD MINIMUMS FOR A FEW HOURS RIGHT NEAR THE MORNING PUSH. THIS
WILL BE A SHORT LIVED EVENT...AND WILL BE OVER BY MID TO LATE
MORNING WITH A RETURN TO VFR BY AFTERNOON. FARTHER NORTH EXPECT KIAG
TO ONLY BE BRUSHED BY THIS...WITH A SHORT PERIOD OF IFR -RASN
POSSIBLE AROUND 10-12Z. BAND MAY EXTEND TOWARDS KROC AS WELL WITH A
BRIEF PERIOD OF IFR SNOW POSSIBLE AROUND 10Z-13Z. EXPECT A SIMILAR
TREND AT KART TO KBUF...JUST A FEW HOURS LATER.
OUTLOOK...
TUESDAY NIGHT...MAINLY VFR.
WEDNESDAY...VFR.
WEDNESDAY NIGHT/THURSDAY ...MVFR/IFR IN RAIN. LOW LEVEL WIND SHEAR
LIKELY.
FRIDAY AND SATURDAY...MVFR. SCATTERED SNOW SHOWERS. LOCAL IFR/LIFR
IN LAKE EFFECT SNOW EAST OF LAKES ERIE AND ONTARIO.
&&
.MARINE...
AN AREA OF LOW PRESSURE WILL CONTINUE TO DROP ACROSS SOUTHERN
ONTARIO THIS MORNING...WITH STRENGTHENING SOUTHWEST WINDS. THESE
WINDS WILL CONTINUE TO INCREASE TO 30 KNOTS FOR MUCH OF THIS
MORNING...BEFORE GRADUALLY SUBSIDING THIS AFTERNOON AND EVENING.
SMALL CRAFT ADVISORIES WILL BE IN PLACE ALONG THE LAKE ERIE AND LAKE
ONTARIO NEARSHORE DURING THIS TIME FRAME.
A STRONG WAVE OF LOW PRESSURE WILL WORK NORTH FROM THE LOWER
MISSISSIPPI VALLEY AND BRING INCREASING WINDS ON THE LOWER LAKES
WEDNESDAY THROUGH THURSDAY. ONCE THE LOW LIFTS NORTH OF THE AREA...
STARTING THURSDAY NIGHT STRONG COLD AIR ADVECTION WILL WORK ACROSS
THE LAKES REGION RESULTING IN PERIODS OF STRONG WINDS AND HIGH WAVE
CONDITIONS THROUGH THE WEEKEND. GALES WARNINGS MAY EVENTUALLY NEED
TO BE ISSUED AT SOME POINT DURING THIS PERIOD.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY UNTIL NOON EST TODAY FOR NYZ010-011-
019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LEZ020-
040-041.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 1 AM
EST WEDNESDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LOZ042.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 1 AM EST
WEDNESDAY FOR LOZ045.
&&
$$
SYNOPSIS...SAGE
NEAR TERM...JJP/RSH/SAGE
SHORT TERM...SAGE/TMA
LONG TERM...TMA
AVIATION...HITCHCOCK/JJP
MARINE...SAGE/TMA
