Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 051745
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1245 PM EST THU MAR 5 2015

.SYNOPSIS...
ARCTIC AIR WILL SURGE ACROSS THE REGION TODAY BRINGING A RETURN TO
VERY COLD TEMPERATURES ALONG WITH A FEW LAKE EFFECT SNOW SHOWERS
SOUTHEAST OF LAKE ONTARIO. TONIGHT SHOULD BE THE COLDEST NIGHT OF
THE COMING WEEK AS TEMPERATURES WILL GRADUALLY MODERATE TOWARDS
NORMAL THROUGH THE WEEKEND WITH READINGS POTENTIALLY CLIMBING ABOVE
AVERAGE NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
CLOUDY SKIES THIS AFTERNOON...WITH STREAMERS OF LAKE EFFECT SNOW
FALLING SOUTH OF LAKE ONTARIO. TEMPERATURES AT 850 HPA HAVE DROPPED
TO ABOUT -20C ACROSS THE REGION AND THIS WILL CONTINUE TO GENERATE
ENOUGH INSTABILITY OVER THE LAKE TO PERSIST THESE LIGHT AND NARROW LAKE
EFFECT STREAMERS THROUGH THE DAY. THAT SAID...NOT LOOKING FOR MUCH
ACCUMULATION IN SNOW WITH THE SHALLOW INVERSION HEIGHTS OF 4-5K
FEET. EAST OF LAKE ERIE THERE MAY BE A SPOT FLURRY ACROSS THE HIGHER
TERRAIN.

MID LEVEL MOISTURE WILL REMAIN ACROSS THE REGION TO THE NORTH OF A
FRONTAL BOUNDARY LYING TO OUR SOUTH. THIS MOISTURE COMBINED WITH THE
PASSAGE OF THE MID LEVEL SHORTWAVE WILL GENERATE CLOUDS THROUGH THE
DAY...WITH ANY CLEARING ACROSS THE SAINT LAWRENCE VALLEY AND NIAGARA
RIVER REGION NOT UNTIL LATE THIS AFTERNOON. OTHERWISE THE REGION WILL
HAVE TO WAIT TILL TONIGHT BEFORE CLEARING COMMENCES.

TEMPERATURES WILL CHANGE LITTLE TODAY AS ONGOING COLD ADVECTION WILL
OFFSET MUCH OF THE DIABATIC HEATING...LEADING TO HIGHS THAT WILL
BARELY CREEP INTO THE LOW TO MID TEENS.

ONCE THE MID LEVEL TROUGH PASSES THE REGION THIS EARLY EVENING...AND
COMBINED WITH SURFACE HIGH PRESSURE AND DRIER AIR...SKIES WILL
BEGIN TO CLEAR IN EARNEST ACROSS THE REGION. THE CLEARING SKIES AND
DIMINISHING WINDS TONIGHT WILL BE REGION-WIDE WITH THE ONLY
EXCEPTION BEING SOUTHEAST OF LAKE ONTARIO WHERE LAKE EFFECT CLOUD
COVER IS EXPECTED TO LINGER THROUGH A GOOD PORTION OF THE NIGHT. THE
LIGHT WINDS AND LARGELY CLEAR SKIES COUPLED WITH THE VERY COLD AND
DRY AIR OVERHEAD WILL PROMOTE STRONG RADIATIONAL COOLING WITH
READINGS PLUNGING INTO THE SINGLE DIGITS EITHER SIDE OF ZERO...WITH
AREAS NEAR THE LAKES STAYING ABOVE ZERO WHILE AREAS INLAND WILL
LIKELY DROP BELOW ZERO. THE LIGHT EVENING BREEZE SHOULD DIMINISH
ALMOST ENTIRELY AS HIGH PRESSURE SHIFTS OVERHEAD TONIGHT AND WHILE
WINDS CHILLS WILL CERTAINLY WILL RUN CLOSE TO ADVISORY LEVELS...THEY
SHOULD STAY JUST A HAIR ABOVE THE -15 THRESHOLD THANKS TO THE
SLACKENING WINDS OVERNIGHT.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ARCTIC HIGH PRESSURE WILL EXTEND ACROSS THE FORECAST AREA FRIDAY
PROVIDING DRY WEATHER AND A GOOD AMOUNT OF COLD SUNSHINE THROUGH
PARTLY CLOUDY SKIES WITH TEMPERATURES STRUGGLING TO REACH INTO THE
UPPER TEENS. CLOUDS WILL INCREASE FROM THE WEST LATER IN THE DAY
AHEAD OF A SURFACE TROUGH PUSHING ACROSS THE CENTRAL GREAT LAKES.

MODELS SHOW THIS SURFACE TROUGH WITH ASSOCIATED SYNOPTIC MOISTURE
AND SUPPORT FROM A 850MB SHORTWAVE TROUGH ALOFT WILL CROSS THE LOWER
GREAT LAKES EARLY SATURDAY MORNING INTO AFTERNOON. 00Z GFS IS A BIT
FASTER THAN 00Z ECMWF WHICH HOLDS BACK THE ARRIVAL OF SNOW UNTIL
SATURDAY AFTERNOON. MOISTURE WILL BE LIMITED TO JUST A FEW
HUNDREDTHS QPF BUT WITHIN AN ARCTIC AIRMASS A COATING TO AN INCH OF
FLUFFY DENDRITES COULD ACCUMULATE WITH HIGHEST PROBABILITIES FOCUSED
ACROSS THE NORTH COUNTY. THE SOUTHWEST FLOW AHEAD OF THE SURFACE
TROUGH AXIS WILL HELP BOOST TEMPS TOWARD 30 DEGREES SATURDAY.

ON THE HEELS OF SATURDAYS TROUGH PASSAGE A WEAK CLIPPER IS FORECAST
TO QUICKLY CROSS THE GREAT LAKES. THIS CLIPPER LOOKS TO FEATURE A
BIT MORE MOISTURE AND BETTER UPPER LEVEL SUPPORT THAT THE PREVIOUS
SURFACE TROUGH. A 500MB SHORTWAVE TROUGH AND EMBEDDED VORT MAX
SHOULD BRING A HIGHER PROBABILITY OF WIDESPREAD SNOW WITH LIKELY
POPS FEATURED SATURDAY NIGHT. THE 00Z ECMWF IS NOW BETTER ALIGNED
WITH THE GFS WHICH SUPPORTS THE INCREASE IN POPS. THE SNOW AND CLOUD
COVER AND MISSING DIRECT PATHWAY TO ARCTIC AIR WILL KEEP OVERNIGHT
TEMPS SATURDAY MUCH WARMER THAN THE PREVIOUS TWO NIGHTS. LOWS ONLY
FALLING INTO THE TEENS ACROSS THE NORTH COUNTY AND LOWER 20S
ELSEWHERE. CHANCES OF LINGERING SNOW SHOWERS SUNDAY AS THE CLIPPER
DEPARTS ACROSS NEW ENGLAND. YET ANOTHER WEAK SYSTEM WILL BE WORKING
ACROSS THE UPPER LAKES BEHIND THIS CLIPPER WITH WEAK WARM ADVECTION
SUPPORTING HIGHS PUSHING TOWARD THE FREEZING MARK.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ONE LAST SURFACE TROUGH AND SUPPORTING 500MB SHORTWAVE IS FORECAST
TO CROSS THE LOWER GREAT LAKES SUNDAY INTO MONDAY WITH A CHANCE OF
SOME MORE LIGHT SNOW SHOWERS. THIS SHORTWAVE LOOKS TO FINALLY KICK
THE GREAT LAKES TROUGH OFF THE EAST COAST. WARMING ALOFT AS A
PROGRESSIVE ZONAL 500MB FLOW TAKES SHAPE INTO NEXT WEEK WILL HELP
BOOST TEMPERATURES BACK TOWARD NORMAL ON MONDAY THEN FINALLY INTO AT
LEAST THE 40S TUESDAY AND WEDNESDAY WITH SOME 00Z GUIDANCE EVEN
SUGGESTING A CHANCE AT 50 ACROSS PORTIONS OF WESTERN NEW YORK.
BOTH DAYS SHOULD REMAIN DRY AS A SYSTEM MOVES THROUGH THE SOUTHEAST
AND MID ATLANTIC...WITH A SECOND NORTHERN STREAM SYSTEM MOVING
THROUGH CENTRAL QUEBEC LEAVING WEAK HIGH PRESSURE BETWEEN ACROSS THE
LOWER GREAT LAKES.

LOOKING A LITTLE FARTHER AHEAD...MODEL GUIDANCE DIVERGES ON HOW LONG
THE WARMING TREND WILL LAST. THE 00Z ECMWF KEEPS A PROGRESSIVE ZONAL
WITHIN THE POLAR JET ACROSS SOUTHEAST CANADA FOR THE SECOND HALF OF
NEXT WEEK WITH A SOUTHERN STREAM CUT OFF LOW DEVELOPING OVER BAJA.
THIS WOULD KEEP TEMPERATURES NEAR TO ABOVE NORMAL FOR THE REST OF
THE WEEK. THE 00Z GFS LOOKS TO HAVE FLIP-FLOPPED WITH THE 12Z ECMWF
WITH A BROAD TROUGH ACROSS SOUTHEAST CANADA AND THE GREAT LAKES FOR
THE SECOND HALF OF NEXT WEEK WHICH WOULD SUGGEST A RETURN TO BELOW
NORMAL TEMPS. STAY TUNED.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
COLD NORTHWEST WINDS WILL MAINTAIN LOW CLOUDS (MVFR/LOW VFR) AND
SCATTERED LAKE EFFECT SNOW SHOWERS SOUTH OF LAKE ONTARIO THIS
AFTERNOON. WITHIN THESE NARROW LAKE EFFECT STREAMERS WILL BE
LOCALIZED MVFR/IFR VSBYS. WILL INCLUDE BRIEF MVFR VSBYS FOR
KBUF/KIAG AND THE KROC AIRFIELDS...WITH LAKE EFFECT SNOW ACTIVITY
LIKELY PERSISTING THE LONGEST ACROSS THE KROC AIRFIELD.

WINDS WILL SLOWLY BACK AROUND TO WESTERLY AS HIGH PRESSURE FROM THE
MID WEST PUSHES EASTWARD AND THIS SHIFT IN WIND FLOW WILL TAKE LIGHT
SNOW SHOWERS TOWARDS THE SOUTHEAST AND THEN EASTERN END OF THE LAKE
ONTARIO. COUPLED WITH THE AREA OF HIGH PRESSURE WILL BE DRIER AIR
WHICH WILL ERODE THE DECK OF CLOUDS HANGING OVER THE AIRFIELDS THIS
AFTERNOON. EXPECT AN IMPROVEMENT BACK TO VFR BY THIS EARLY EVENING
FOR ALL TAF SITES...WITH VFR FLIGHT CONDITIONS THEN PERSISTING
THROUGH THE REMAINDER OF THE TAF CYCLE. ONLY EXCEPTION MAYBE SOME
MVFR CIGS ACROSS KART DURING THE LAST 6 HOURS OF THE TAF CYCLE FROM
WEAKENING LAKE EFFECT ACTIVITY.

OUTLOOK...
FRIDAY AFTERNOON...VFR.
FRIDAY NIGHT...MAINLY VFR WITH A CHANCE OF SNOW SHOWERS LATE.
SATURDAY...MVFR/IFR WITH SNOW SHOWERS BECOMING LIKELY.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF SNOW SHOWERS.
TUESDAY...VFR.

&&

.MARINE...
AS HIGH PRESSURE FROM THE MID WEST BUILDS EASTWARD THIS AFTERNOON
WINDS OVER THE LAKES WILL CONTINUE TO AVERAGE LESS THAN 15 KNOTS. AS
THE AREA OF HIGH PRESSURE CRESTS THE LAKES TONIGHT WINDS WILL BECOME
LIGHTER TONIGHT. BRISK SOUTHWEST FLOW WILL DEVELOP ON THE LAKES
TOMORROW AS THE HIGH SHIFTS TO THE EAST AHEAD OF ANOTHER CLIPPER
THAT WILL CROSS THE EASTERN GREAT LAKES THIS WEEKEND.

&&

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

&&

$$

SYNOPSIS...WOOD
NEAR TERM...THOMAS/WOOD
SHORT TERM...SMITH
LONG TERM...HITCHCOCK/SMITH
AVIATION...THOMAS
MARINE...THOMAS







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