Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 050449
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1149 PM EST WED MAR 4 2015

.SYNOPSIS...
AN ARCTIC COLD FRONT WILL PUSH SOUTH ACROSS THE REGION OVERNIGHT
WITH ANOTHER ROUND OF LIGHT SNOW WHILE USHERING IN A FRESH BATCH OF
VERY COLD AIR. THE BITTER COLD AIR WILL CONTINUE TO POUR OVER THE
EASTERN GREAT LAKES THURSDAY WITH LITTLE MODERATION IN
TEMPERATURES...WHILE LIGHT LAKE EFFECT SNOW SHOWERS WILL COAT THE
GROUND SOUTH OF LAKE ONTARIO.

&&

.NEAR TERM /THROUGH THURSDAY/...
AN ARCTIC FRONT WILL PUSH ACROSS THE FORECAST AREA OVERNIGHT...
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. SNOW
SHOWERS ASSOCIATED WITH THE FRONT WILL END BY DAWN TOMORROW MORNING
TO OUR SOUTH.

TEMPERATURES WILL FALL MAINLY 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 THURSDAY MORNING...
AND REMAIN AT THIS LEVEL THROUGH THE DAY. WITH CLOUDY SKIES...OUR
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 /06Z THURSDAY THROUGH MONDAY/...
AN ARCTIC COLD FRONT PUSHING ACROSS THE REGION OVERNIGHT WILL
PRODUCE WIDESPREAD MVFR CONDITIONS OVER THE WESTERN COUNTIES THROUGH
09Z...WITH IFR CONDITIONS IN LAKE ENHANCED SNOW NEAR ROCHESTER.
CONDITIONS SHOULD GRADUALLY IMPROVE TOWARDS DAYBREAK...WITH VFR
CONDITIONS EXPECTED ACROSS THE MAJORITY OF THE REGION ON THURSDAY
WHEN HIGH PRESSURE WILL BUILD OUR WAY FROM THE UPPER MID WEST.

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 OVERNIGHT. 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. A SMALL CRAFT ADVISORY FOR THE WESTERN
HALF OF THE LAKE WILL THUS REMAIN IN EFFECT 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...RSH/THOMAS






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