Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 201129
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
629 AM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD FROM THE CENTRAL GREAT LAKES TO NEW ENGLAND
THIS WEEKEND...WHILE BRINGING DRYING CONDITIONS AND NEAR NORMAL
TEMPERATURES TO OUR REGION. THIS WILL BE FOLLOWED BY A WARMING TREND
EARLY NEXT WEEK...WITH A STORM SYSTEM THEN DEVELOPING OVER THE GREAT
LAKES AROUND THE CHRISTMAS HOLIDAY AND POTENTIALLY BRINGING OUR AREA
A ROUND OF STRONG WINDS...ALONG WITH RAIN EVENTUALLY CHANGING OVER
TO SOME SNOW.

&&

.NEAR TERM /THROUGH TONIGHT/...
THIS WILL BE A QUIET PERIOD AS HIGH PRESSURE DRAPED ACROSS ONTARIO
PROVINCE AND THE CENTRAL GREAT LAKES BUILDS EASTWARD ACROSS NEW YORK
STATE. THIS WILL PROMOTE DRY WEATHER...THOUGH LOWER CLOUDS WILL
LINGER IN PLACE ACROSS MUCH OF THE AREA AS LOW LEVEL MOISTURE
REMAINS TRAPPED UNDERNEATH A STRONG AND SLOWLY LOWERING SUBSIDENCE
INVERSION. THE MAIN EXCEPTION TO THIS WILL BE ACROSS THE NORTH
COUNTRY...WHERE STRONGER DRYING AND THE LACK OF AN OFF LAKE FLOW
SHOULD ALLOW FOR MORE SUNSHINE. SOME PARTIAL SUNSHINE MAY ALSO
DEVELOP ACROSS FAR WESTERN NEW YORK TODAY...BUT THIS MAY BE
LIMITED DUE TO APPROACHING AREA OF MID LEVEL CLOUDINESS PUSHING
NORTHEAST FROM THE SOUTHERN GREAT LAKES/OHIO VALLEY. HIGHS TODAY
IN THE UPPER 20S/LOWER 30S. LOWS TONIGHT MAINLY IN THE 20S.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
HIGH PRESSURE WILL REMAIN ANCHORED ACROSS NORTHERN NEW ENGLAND AND
EASTERN QUEBEC ON SUNDAY WITH GENERALLY LIGHT WINDS ACROSS THE
FORECAST AREA. ALTHOUGH LOW LEVEL MOISTURE WILL BE TRAPPED BELOW THE
SUBSIDENCE INVERSION...IT APPEARS THAT THE LOWER LAYERS WILL NOT BE
SATURATED ENOUGH TO SUPPORT A THICK LAYER OF CLOUDINESS...SO MUCH OF
SUNDAY SHOULD BE MOSTLY SUNNY. HIGH TEMPS ON SUNDAY SHOULD REACH THE
LOWER TO MIDDLE 30S.

THE SURFACE HIGH AND UPPER RIDGING WILL MOVE FARTHER TO THE EAST ON
MONDAY AND THE UPPER TROUGH ACROSS THE CENTRAL PLAINS WILL DEEPEN.
THIS BRING A RETURN FLOW FROM THE SOUTH AND AN INCREASE IN DEEP
LAYER MOISTURE. CLOUDS WILL BE ON THE INCREASE DURING MONDAY BUT THE
SOUTHERLY WINDS WILL ALSO BRING A WARMING WITH HIGH TEMPS ON MONDAY
IN THE MID 30S ACROSS THE HIGHER TERRAIN AND THE LOWER 40S FOR THE
LOWER ELEVATIONS. THE RISK OF PRECIP SHOULD HOLD OFF MONDAY NIGHT AS
A NARROW AND SHALLOW SURFACE RIDGE EXTENDS SOUTHWEST TO NORTHEAST
ACROSS THE FORECAST AREA AND KEEPS THE CHANCE OF PRECIP TO OUR SOUTH
AND WEST.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
ALL EYES THEN FOCUS ON THE POTENTIAL FOR A TRAVEL DISRUPTING WINTER
STORM ACROSS THE GREAT LAKES AND NORTHEAST STATES LEADING UP TO
AND FOLLOWING THE CHRISTMAS HOLIDAY. THE OVERALL THEME WILL BE A
COMPLEX AREA OF LOW PRESSURE SPINNING ACROSS THE GREAT LAKES WITH
AND ASSOCIATED COLD/OCCLUDED FRONT SHIFTING NORTHEAST ACROSS THE
OHIO VALLEY...MID-ATLANTIC AND NORTHEAST STATES. ON CHRISTMAS EVE
WARM MOIST AIR ADVECTING NORTH AHEAD OF THE FRONT WILL BRING RAIN
WITH MILD TEMPERATURES TO WESTERN AND NORTH-CENTRAL NEW YORK. A
PERIOD OF GUSTY WINDS IS LIKELY ALONG AND JUST BEHIND THIS FRONT
THEN COLD AIR ADVECTION WILL BRING A CHANGEOVER TO SNOW ON
CHRISTMAS DAY AS TEMPERATURES COOL ALONG WITH ANOTHER PERIOD OF STRONG
WINDS POSSIBLE.

FINER DETAILS...ON TUESDAY INTO TUESDAY NIGHT ISENTROPIC UPGLIDE AND
WARM AIR ADVECTION WILL BRING CHANCES FOR RAIN SHOWERS ACROSS OUR
FORECAST AREA. GUIDANCE INDICATES SURFACE TEMPERATURES WILL WARM
INTO THE 40S THEN REMAIN NEARLY STEADY OR RISE TUESDAY NIGHT
REACHING NEAR 50 DEGREES BY CHRISTMAS EVE. 90 PERCENT OF NAEFS
ENSEMBLE MEMBERS INDICATE ABOVE CLIMO PWATS SO THERE COULD BE SOME
PERIODS OF MODERATE RAINFALL DURING TUESDAY INTO WEDNESDAY.

THE COLD/OCCLUDED FRONT LOOKS TO CROSS WESTERN AND CENTRAL NEW YORK
ON CHRISTMAS EVE. A 50-60KT LOW LEVEL JET OUT IN FRONT MAY BRING
SOME STRONG CONVECTIVELY DRIVEN WINDS BUT THERE IS ALSO A DOWNSLOPE
WIND THREAT AS WINDS FORCED OVER THE HIGHER TERRAIN OF THE SOUTHERN
TIER AND TUG HILL DESCEND DOWN TO THE LAKE SHORES. FOLLOWING THE
FRONTAL PASSAGE COLD AIR WILL BEGIN TO WORK ACROSS THE LOWER GREAT
LAKES REGION. WITHOUT A STEEP RIDGE IN THE WEST THE SOURCE REGION OF
THIS COLD AIR WILL BE PACIFIC BASED AND NOT ARCTIC BASED SO THIS
LACK OF AN ARCTIC AIRMASS WILL BRING A REDUCED THREAT OF ANY
SIGNIFICANT LAKE SNOWS DEVELOPING AS 850MB TEMPS SHOULD ONLY DROP TO
AROUND -8C TO -10C. THIS WILL BE COLD ENOUGH HOWEVER FOR AN OVERALL
CHANGE FROM RAIN TO SNOW WITH A LAKE ENHANCEMENT PENDING AVAILABLE
POST-FRONTAL MOISTURE.

ANOTHER PERIOD OF STRONG WINDS IS POSSIBLE ON CHRISTMAS DAY WITHIN
THE COLDER AIRMASS BEHIND THE FRONT. COLD AIR ADVECTION WILL STEEPEN
LOW LEVEL LAPSE RATES HELPING TO MIX 850MB WINDS OF 40-50KTS DOWN TO
THE SURFACE. THE 12Z ECMWF IS A BIT STRONGER WITH THIS LOW LEVEL JET
SHOWING 50-60KTS. THERE IS STILL LACK OF FINER DETAILS IN EXACT
TIMING AND LOCATION OF THE WEATHER IMPACTS DURING THE WEEK OF
CHRISTMAS. THE FORECAST WILL CONTINUALLY BE UPDATED AS WE GET CLOSER
AND THOSE WITH TRAVEL PLANS WILL WANT TO PAY CLOSE ATTENTION TO
THESE FORECAST UPDATES THROUGHOUT THE WEEKEND INTO NEXT WEEK.

BEYOND CHRISTMAS...MODELS SHOW A BRIEF PERIOD OF FAIR WEATHER
POSSIBLE ON FRIDAY AS SHORTWAVE RIDGING QUICKLY SHIFTS ACROSS THE
LOWER GREAT LAKES. FURTHER OUT WE WILL BE WATCHING NEXT WEEKEND FOR
ANOTHER POSSIBLE GREAT LAKES CUTTER STORM WHICH COULD BRING ANOTHER
ROUND OF GUSTY WINDS.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MAINLY MVFR CONDITIONS WILL PREVAIL THIS MORNING AS A LOW STRATUS
DECK REMAINS LOCKED IN PLACE...WITH SOME ENHANCEMENT OFF THE LAKES.
THE EXCEPTION IS AT KART AND THE NORTH COUNTRY...WHERE NORTHERLY
FLOW DOES NOT BRING ADDED MOISTURE FROM THE LAKES...RESULTING IN
VFR CONDITIONS. DUE TO THE HIGHER ELEVATIONS...IFR CIGS ARE
POSSIBLE ALONG THE SOUTHERN TIER THIS MORNING.

OUTLOOK...
THIS AFTERNOON AND TONIGHT...GRADUAL IMPROVEMENT TO VFR.
SUNDAY AND MONDAY...VFR.
MONDAY NIGHT...MAINLY VFR WITH A CHANCE OF RAIN OR SNOW.
TUESDAY...VFR/MVFR WITH A CHANCE OF RAIN.
WEDNESDAY...VFR/MVFR WITH RAIN...GUSTY WINDS ARE ALSO POSSIBLE.

&&

.MARINE...
HIGH PRESSURE BUILDING FROM CENTRAL ONTARIO AND THE CENTRAL GREAT
LAKES TO NEW ENGLAND WILL BRING A PERIOD OF RELATIVELY TRANQUIL
CONDITIONS THAT WILL LAST THROUGH THE WEEKEND.

LOOKING FURTHER OUT INTO NEXT WEEK...RELATIVELY QUIET CONDITIONS
SHOULD CONTINUE UNDER A MODEST SOUTHEASTERLY FLOW REGIME MONDAY AND
TUESDAY...BEFORE A DEVELOPING STORM SYSTEM POTENTIALLY BRINGS
STRONGER WINDS TO THE REGION CHRISTMAS EVE AND CHRISTMAS DAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...TMA
MARINE...TMA



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