Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 042357
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
657 PM EST WED MAR 4 2015

.SYNOPSIS...
AN ARCTIC FRONT WITH A FEW SNOW SHOWERS WILL DROP ACROSS THE REGION
THROUGH THE EVENING HOURS. THIS FRONT WILL USHER IN MUCH COLDER AIR
AS OVER NIGHT TEMPERATURES WILL PLUMMET INTO THE SINGLE DIGITS. COLD
AIR WILL CONTINUE TO POUR OVER THE EASTERN GREAT LAKES TOMORROW WITH
JUST A LITTLE MODERATION IN AIR TEMPERATURES...WHILE LIGHT LAKE
EFFECT SNOW SHOWERS FLY SOUTH OF LAKE ONTARIO.

&&

.NEAR TERM /THROUGH THURSDAY/...
AN ARCTIC FRONT WILL PUSH ACROSS THE FORECAST AREA THIS EVENING...
PRODUCING SOME LIGHT SNOW SHOWERS AS IT WILL USHER A FRESH COLD
AIRMASS INTO THE REGION. LIMITED MOISTURE ALONG THE FRONTAL BOUNDARY
ALONG WITH SHALLOW LIFT WILL KEEP SNOW ACTIVITY TO A MINIMUM. AS
THIS FRONT DROPS SOUTHWARD ACROSS THE CWA THERE WILL BE CHANCES FOR
SNOW SHOWERS THROUGH ABOUT MIDNIGHT...BUT LACKING UPPER LEVEL
SUPPORT OF A STRONG SHORTWAVE OVERALL ACCUMULATIONS WILL LIKELY BE A
COATING OR LESS. SNOW SHOWERS ASSOCIATED WITH THE FRONT WILL END BY
DAWN TOMORROW MORNING TO OUR SOUTH.

TEMPERATURES WILL FALL INTO THE SINGLE DIGITS AS COLD AIR ADVECTION
CONTINUES THROUGH THE NIGHT BEHIND THE ARCTIC FRONT. TEMPERATURES AT
850 HPA WILL DROP TO NEAR -20C TOMORROW MORNING...AND REMAIN AT THIS
LEVEL THROUGH THE DAY TOMORROW. WITH CLOUDY SKIES THROUGH THE DAY
TOMORROW OUR AIR TEMPERATURES WILL ONLY RECOVER A FEW DEGREES...WITH
HIGHS IN THE LOWER TEENS.

THIS COLDER AIR POURING OVER LAKE ONTARIO WILL ALSO GENERATE SOME
LIMITED LAKE EFFECT SNOW SHOWERS. INVERSION HEIGHTS WILL REMAIN 3-4K
FEET AND THOUGH THE COLD AIR MASS WILL CREATE MODERATE LAKE
INSTABILITY...THE LOW INVERSION HEIGHTS AND MULTIBANDED
CHARACTERISTICS TO THE LAKE EFFECT SNOW BANDS WILL HOLD ACCUMULATIONS
FROM LATE TONIGHT THROUGH THE DAY TOMORROW TO AROUND AN INCH OR TWO
SOUTH OF LAKE ONTARIO.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
THURSDAY NIGHT STRONG ARCTIC HIGH PRESSURE WILL BUILD EAST ACROSS
THE OHIO VALLEY WITH A RIDGE EXTENDING NORTHEASTWARD INTO THE LOWER
LAKES. THIS WILL PROVIDE CLEARING SKIES FOR THE BULK OF THE AREA...
BUT THE UNSEASONABLY COLD AIRMASS WILL STILL SUPPORT AT LEAST A
CHANCE OF A FEW LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO.
LAKE INDUCED EQUILIBRIUM LEVELS REMAIN AROUND 6K FEET DURING THE
EVENING...THEN LOWER TO BELOW 5K FEET OVERNIGHT AS THE RIDGE AXIS
CRESTS OVERHEAD. THE RELATIVELY LOW INVERSION HEIGHTS...SHORT
FETCH...AND DRY AIRMASS WILL GREATLY LIMIT ORGANIZATION AND
INTENSITY OF LAKE EFFECT SNOW SHOWERS...BUT MAY NOT PREVENT THEM
ALTOGETHER. WITH THIS IN MIND HAVE KEPT SOME CHANCE POPS FROM THE
EASTERN SUBURBS OF ROCHESTER TO OSWEGO COUNTY THURSDAY NIGHT. IF
THESE MATERIALIZE ANY ACCUMULATION WILL BE MINOR.

OTHERWISE IT WILL BE A COLD NIGHT WITH CLEARING SKIES OUTSIDE OF THE
LAKE EFFECT CLOUDS AS THE RIDGE BUILDS OVERHEAD. WINDS MAY NOT FULLY
DECOUPLE...BUT THE COMBINATION OF LIGHTER WINDS...CLEAR SKIES AND A
COLD/DRY AIRMASS WILL SUPPORT GOOD RADIATIONAL COOLING. THE LAKE
PLAINS WILL DROP TO AT LEAST THE LOW SINGLE DIGITS AND POSSIBLY JUST
BELOW ZERO...WITH LOWS OF 5 TO 10 BELOW MORE LIKELY ACROSS THE
COLDER SOUTHERN TIER VALLEYS AND NORTH COUNTRY. WINDS WILL BE FAIRLY
LIGHT...BUT STILL MAY BE JUST ENOUGH TO DROP WIND CHILLS INTO THE 10
TO 15 BELOW ZERO RANGE.

ON FRIDAY ANYTHING THAT REMAINS OF THE LAKE EFFECT CLOUDS AND LIGHT
FLURRIES WILL MOVE NORTH ACROSS THE EASTERN LAKE ONTARIO REGION AS
BOUNDARY LAYER FLOW BACKS TO THE SOUTHWEST. BY AFTERNOON IF ANYTHING
IS LEFT IT WILL BE NORTH OF THE AREA FROM POINT PETRE TO KINGSTON
ONTARIO. OTHERWISE THE REST OF THE AREA SHOULD SEE A DECENT AMOUNT
OF SUNSHINE WITH HIGH CLOUDS INCREASING FROM NORTHWEST TO SOUTHEAST
IN THE AFTERNOON AHEAD OF THE NEXT SYSTEM. TEMPERATURES WILL REMAIN
WELL BELOW NORMAL ALTHOUGH NOT QUITE AS COLD AS THURSDAY. EXPECT
HIGHS IN THE UPPER TEENS TO LOWER 20S IN MOST AREAS.

LATER FRIDAY NIGHT AND SATURDAY A MID LEVEL TROUGH WILL QUICKLY
SWING ACROSS QUEBEC...WITH AN ASSOCIATED SURFACE OCCLUDED
FRONT/TROUGH MOVING ACROSS THE LOWER LAKES ON SATURDAY. WEAK LARGE
SCALE ASCENT FROM A LEAD SHORTWAVE AND WARM ADVECTION WILL
OVERSPREAD THE NORTH COUNTRY FRIDAY NIGHT AND MAY PRODUCE A FEW
FLURRIES OR LIGHT SNOW SHOWERS. A LITTLE BETTER PERIOD OF ASCENT
WILL SPREAD ACROSS THE AREA SATURDAY WITH THE PASSAGE OF THE SURFACE
TROUGH AND UPPER LEVEL SHORTWAVE. THIS WILL PRODUCE A LITTLE BETTER
CHANCE OF SNOW SHOWERS SATURDAY...WITH THE BEST CHANCES LIKELY EAST
OF LAKES ERIE AND ONTARIO WHERE FRICTIONAL CONVERGENCE AND UPSLOPE
FLOW ACROSS THE HIGHER TERRAIN EAST OF LAKE WILL GIVE AN ADDED
BOOST. TEMPERATURES WILL CONTINUE AN UPWARD TREND WITH HIGHS IN THE
UPPER 20S TO LOWER 30S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODEL GUIDANCE BEGINS TO DIVERGE DURING THE SECOND HALF OF THE
WEEKEND WITH RESPECT TO THE TIMING AND STRENGTH OF NUMEROUS
INDIVIDUAL SHORTWAVES MOVING THROUGH THE MEAN NORTHWEST FLOW ALOFT.
THE 12Z GFS CONTINUES TO PUT EMPHASIS ON A SHORTWAVE AND ASSOCIATED
CLIPPER LOW FOR LATER SATURDAY NIGHT AND SUNDAY WITH A PERIOD OF
LIGHT SNOW. THE 12Z ECMWF ON THE OTHER HAND HAS HIGH PRESSURE OVER
THE LOWER LAKES SUNDAY...WITH THE BULK OF THE SHORTWAVE ENERGY ON
SATURDAY AND THEN AGAIN MONDAY. THE 12Z GEFS ENSEMBLES SHOW A
VARIETY OF SOLUTIONS WITH SOME CLOSER TO THE OPERATIONAL GFS...AND
SOME CLOSER THE ECMWF. GIVEN THE MODEL UNCERTAINTY...HAVE KEPT A
CHANCE OF SNOW SHOWERS FOR THE ENTIRE PERIOD FROM SUNDAY THROUGH
MONDAY. TEMPERATURES WILL CONTINUE A SLOW UPWARD TREND WITH HIGHS IN
THE LOWER TO MID 30S IN MOST AREAS.

TUESDAY INTO WEDNESDAY THE PAST FEW MODEL RUNS HAVE SHOWN THE
POTENTIAL FOR A MORE SIGNIFICANT WARMING TREND. BOTH THE GFS AND
ECMWF BRING RISING HEIGHTS AND WARM ADVECTION EAST ACROSS THE NATION
INTO THE GREAT LAKES AND EVENTUALLY NORTHEAST THROUGH THE MIDDLE OF
NEXT WEEK AS A TROUGH DIGS INTO THE NORTHERN ROCKIES. BOTH MODELS
BRING 850MB TEMPS ABOVE ZERO BY TUESDAY...WHICH WOULD SUPPORT HIGHS
INTO THE LOWER TO MID 40S IN MANY AREAS. 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 LAKES.

LOOKING A LITTLE FARTHER AHEAD...MODEL GUIDANCE DIVERGES ON HOW LONG
THE WARMING TREND WILL LAST. THE NEW 12Z ECMWF DEVELOPS A BROAD
TROUGH ACROSS SOUTHEAST CANADA FOR THE SECOND HALF OF NEXT WEEK...
WHICH FORCES A BACKDOOR FRONT ACROSS OUR AREA LATER WEDNESDAY. THIS
WOULD KEEP TEMPERATURES RELATIVELY COOL...BUT NOT COLD FOR THE REST
OF THE WEEK. THE GFS ON THE OTHER HAND KEEPS A WARM AIRMASS IN PLACE
WEDNESDAY AND THURSDAY BEFORE A STRONGER COLD FRONT MOVES THROUGH
FRIDAY. MARCH AND APRIL IS THE PEAK SEASON CLIMATOLOGICALLY FOR
BACKDOOR COLD FRONTS...SO SUSPECT A MORE BRIEF WARM-UP IS MORE
LIKELY AT THIS POINT.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A COLD FRONTAL PASSAGE WILL PRODUCE SOME LIGHT SNOW SHOWERS
TONIGHT...WITH VFR CONDITIONS POSSIBLY DETERIORATING TO MVFR FOR A
FEW HOURS IN THE PROCESS. THE SOUTHERN TIER AIRFIELDS THAT SIT ON
THE RIDGES (KJHW/KELZ) SHOULD EXPERIENCE MVFR CIGS THROUGH THE
NIGHT.

HIGH PRESSURE WILL BEGIN TO BUILD EASTWARD ACROSS THE TAF SITES ON
THURSDAY WITH MAINLY VFR CIGS GRADUALLY GIVING WAY TO SOME CLEARING
DURING THE MIDDAY AND AFTERNOON.

OUTLOOK...
THURSDAY NIGHT AND FRIDAY...A WEAK BAND OF LAKE EFFECT SNOW WITH
IFR/MVFR VSBYS SOUTHEAST OF LAKE ONTARIO THURSDAY NIGHT SHIFTING TO
EAST OF THE LAKE FRIDAY AND DIMINISHING. OTHERWISE VFR.
SATURDAY...MVFR/IFR IN SNOW SHOWERS LIKELY EAST OF THE LAKES.
SUNDAY AND MONDAY...MAINLY VFR.

&&

.MARINE...
AN ARCTIC FRONT WILL DROP ACROSS LAKE ONTARIO THIS EVENING AND WINDS
WILL SHIFT FROM SOUTHWEST AHEAD OF THE FRONT TO NORTHWEST BEHIND THE
FRONT. WITH COLD AIR ADVECTION WINDS WILL INCREASE IN SPEED TO 20 TO
25 KNOTS OVER LAKE ONTARIO TONIGHT. FOR SUCH WILL ISSUE A SMALL
CRAFT ADVISORY FOR THE WESTERN HALF OF THE LAKE THROUGH THURSDAY
MORNING. HIGH PRESSURE BUILDING TOWARDS THE EASTERN GREAT LAKES
REGION WILL DIMINISH THE WINDS THROUGH THE DAY THURSDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR LOZ042-043.

&&

$$

SYNOPSIS...RSH/THOMAS
NEAR TERM...RSH/THOMAS
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...RSH/THOMAS
MARINE...THOMAS






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