Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 160254
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
954 PM EST MON DEC 15 2014

.SYNOPSIS...
LOW PRESSURE OVER IOWA WILL SLOWLY LIFT ACROSS LOWER MICHIGAN AND
SOUTHERN ONTARIO OVERNIGHT THROUGH WEDNESDAY WHILE BRINGING A FEW
ROUNDS OF SHOWERS. FOLLOWING THIS SYSTEM...A WEST-NORTHWESTERLY FLOW
OF COLDER AIR WILL FILTER ACROSS THE REGION AND BRING SOME LAKE
EFFECT SNOW SHOWERS TO AREAS EAST AND SOUTHEAST OF THE LAKES
WEDNESDAY NIGHT AND THURSDAY...BEFORE HIGH PRESSURE BRINGS A RETURN
TO FAIR WEATHER FOR THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF MID EVENING...RIDGING OVER THE NORTHEAST US CONTINUES TO
PRODUCE LARGE SCALE SUBSIDENCE AND AN ATTENDANT STRONG CAP OVER THE
REGION...WITH THE LOW LEVEL MOISTURE TRAPPED UNDERNEATH THIS
INVERSION REMAINING TRAPPED AND THUS UNABLE TO EFFECTIVELY MIX OUT.
THE END RESULT OF ALL THIS IS PERSISTENT STRATUS...ALONG WITH SOME
AREAS OF FOG...MOST NOTABLY ACROSS THE HIGHER TERRAIN AND PORTIONS
OF THE NIAGARA FRONTIER. WHILE SOME OF THIS IS LOCALLY DENSE AT
TIMES...AT THIS POINT WEBCAMS SUGGEST THAT THE AREAL COVERAGE OF
THIS IS NOT GREAT ENOUGH TO WARRANT AN ADVISORY.

FOR THE BALANCE OF THE NIGHT...EXPECT THINGS TO REMAIN ROUGHLY
STATUS QUO FOR AT LEAST A FEW MORE HOURS...WITH CONDITIONS THEN
IMPROVING SOME ACROSS FAR WESTERN NEW YORK OVERNIGHT AS DRIER AIR
CURRENTLY SEEN SPREADING NORTHWARD ACROSS OHIO/PA TRIES TO WORK IN
AT THE LOWER LEVELS. THIS SAID...STILL EXPECT SKIES TO REMAIN CLOUDY
AS MID AND HIGH CLOUDS WILL BE ON THE INCREASE IN ADVANCE OF THE
NEXT SYSTEM.

ON TUESDAY...A SYSTEM OVER IOWA WILL SLOWLY MOVE ACROSS LOWER
MICHIGAN. ATTENDANT WARM AIR ADVECTION ASSOCIATED WITH THE
APPROACH OF AN OCCLUDING FRONTAL BOUNDARY SHOULD SPREAD A 3 TO 6
HOUR-LONG PERIOD OF RAIN SHOWERS ACROSS WESTERN NY AND INTO
CENTRAL NY THROUGH THE DAY...FOLLOWED BY A TRAILING AREA OF MUCH
MORE SCATTERED SHOWERS. EXPECT PRECIP AMOUNTS TO BE ON THE LIGHTER
SIDE...WITH SHORT-TERM MODEL QPF GENERALLY RANGING BETWEEN A TENTH
AND A THIRD OF AN INCH.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
WEAK SURFACE LOW PRESSURE WILL TRACK ACROSS SOUTHERN ONTARIO TUESDAY
NIGHT...BUT THE MAIN SOURCE OF LIFT WILL BE THE LEADING EDGE OF AN
UPPER LEVEL TROUGH AXIS WHICH WILL SWEEP ACROSS THE REGION. ON
TUESDAY EVENING...MODEL GUIDANCE (NAM/GGEM/GFS/SREF) OFFERS A FAIRLY
CLOSE CONSENSUS POSITION FOR THIS FEATURE...WITH STEADY SHOWERS EAST
OF ROCHESTER...AND SCATTERED SHOWERS ACROSS WESTERN PORTIONS. THIS TROUGH
AXIS WILL EXIT TOWARD NEW ENGLAND AFTER MIDNIGHT...LEAVING SCATTERED
LIGHT SHOWERS. LOW LEVEL MOISTURE WILL LINGER TUESDAY EVENING WITH
FOG ACROSS THE HIGHER TERRAIN...BUT AS THE SURFACE LOW TRACKS TO OUR
NORTH...A BRISK SOUTHWESTERLY FLOW WILL USHER IN A DRIER AIRMASS.
EXPECT PRECIPITATION TO BE JUST RAIN FOR MOST OF TUESDAY
NIGHT...WITH MOST GUIDANCE SUGGESTING A THERMAL PROFILE JUST A
BIT TOO WARM FOR SNOW IN OUR CWA. SHOWERS MAY MIX WITH SNOW ACROSS
HIGHER TERRAIN IN WESTERN PORTIONS OF THE SOUTHERN TIER LATE TUESDAY
NIGHT.

COLD AIR ADVECTION WILL BE IN FULL SWING ON WEDNESDAY...BUT IT WILL
TAKE A WHILE FOR 850MB TEMPERATURES TO GET COLD ENOUGH FOR MUCH OF A
LAKE RESPONSE. BY 18Z...CONSENSUS 850MB TEMPS ARE DOWN TO ABOUT -7C
OFF LAKE ERIE...BUT LOWERING EQUILIBRIUM LEVELS LIMITS THE
OPPORTUNITY FOR DENDRITIC SNOW GROWTH. WHILE THERE MAY BE SOME LIGHT
RAIN OR SNOW SHOWERS...DO NOT EXPECT MUCH ACCUMULATION
EAST/NORTHEAST OF LAKE ERIE. MOISTURE WILL BE A BIT DEEPER ALOFT
ACROSS LAKE ONTARIO...BUT 850MB TEMPS WILL TAKE A BIT LONGER TO
COOL. EXPECT THE PRIMARY SOURCE OF LIFT TO BE UPSLOPING WITH A BRISK
35 KT FLOW AT 925 MB. PRIMARILY MORNING RAIN SHOWERS SHOULD
TRANSITION TO SNOW OFF LAKE ONTARIO WEDNESDAY AFTERNOON...WITH LIGHT
ACCUMULATIONS OF AN INCH OR TWO PRIMARILY CONFINED TO HIGHER
ELEVATIONS. HIGHS ON WEDNESDAY SHOULD BE IN THE MID TO UPPER
30S...BUT THESE WILL COME DURING THE MORNING HOURS...WITH MODESTLY
FALLING TEMPERATURES IN THE AFTERNOON DUE TO THE COLD AIR ADVECTION.

THE REGION WILL REMAIN IN A CYCLONIC FLOW WEDNESDAY NIGHT...HOWEVER
TEMPERATURES ALOFT WILL BE A BIT COLDER. INITIALLY...EXPECT LOW
EQUILIBRIUM LEVELS TO LIMIT SNOW OFF LAKE ERIE...BUT MOST GUIDANCE
BRINGS A MORE SUBTLE SECONDARY WAVE ACROSS LATE WEDNESDAY NIGHT
WHICH WILL BOTH PROVIDE MOISTURE AND COOL TEMPERATURES BENEATH THIS
INVERSION TO AROUND -13C WHICH IS BETTER SUITED FOR SNOW GROWTH.
THIS IS LIKELY TO BRING SNOW SHOWERS ACROSS HIGHER TERRAIN EAST OF
LAKE ONTARIO WITH LIGHT ACCUMULATIONS OF A COUPLE INCHES LATE
WEDNESDAY NIGHT AND INTO THURSDAY. 850MB TEMPS WILL BE WARMER OFF
LAKE ONTARIO...BUT CONTINUED MOISTURE ALOFT SHOULD SUPPORT
SNOW...AGAIN MAINLY FROM UPSLOPING ON THE EAST FACE OF THE TUG HILL.
THIS PROBABLY WILL BRING MODEST ACCUMULATIONS IN THE 3 TO 5 INCH
RANGE WEDNESDAY NIGHT INTO THURSDAY. WITH BUFKIT SHOWING LIFT MUCH
BELOW THE DENDRITIC SNOW GROWTH ZONE...EXPECT POOR SNOW RATIOS NEAR
10:1.

THE PASSAGE OF THE SECONDARY TROUGH WILL BRING A MORE NORTHWESTERLY
FLOW TO THE REGION...WHICH WILL PUSH WHAT LAKE MOISTURE THERE IS
SOUTH OF LAKE ONTARIO ON THURSDAY. THIS WILL LIKELY BRING SNOW
SHOWERS TO THE BUFFALO/ROCHESTER AREAS...BUT ACCUMULATIONS SHOULD BE
LIGHT (LESS THAN AN INCH) GIVEN THE MARGINAL LAKE INDUCED CAPES.
OTHERWISE...CLOUD COVER WILL PERSIST THROUGH MOST OF THE TIME PERIOD
WITH A LIMITED DIURNAL TEMPERATURE RANGE. HIGHS ON THURSDAY SHOULD
GENERALLY BE IN THE LOWER 30S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE PRESSURE GRADIENT BETWEEN LOW PRESSURE ACROSS THE CANADIAN
MARITIMES AND HIGH PRESSURE ACROSS THE UPPER LAKES WILL SET UP A
NORTHWESTERLY FLOW THURSDAY NIGHT. A SHALLOW LAYER OF COLD AIR WILL
BE MARGINALLY DEEP ENOUGH FOR LAKE EFFECT SNOW SOUTHEAST OF THE
LAKES. THIS MAY RESULT IN LIGHT AND/OR LOCALIZED ACCUMULATIONS
THURSDAY NIGHT...WITH THIS TAPERING OFF DURING THE DAY FRIDAY AS THE
HIGH NUDGES TOWARD OUR REGION. OUTSIDE OF THESE AREAS...EXPECT
CLOUDY AND CHILLY CONDITIONS.

MODEL GUIDANCE HAS BEEN IN POOR AGREEMENT FOR THE UPCOMING
WEEKEND...BUT 12Z GUIDANCE HAS TRENDED MUCH CLOSER TO A COMMON
CONSENSUS. A DIFFUSE SHORTWAVE IS FORECAST TO DROP ACROSS THE UPPER
PLAINS FRIDAY NIGHT. LOW PRESSURE ASSOCIATED WITH THIS WAVE WILL
DEVELOP IN THE SOUTHEASTERN OR MID ATLANTIC STATES SATURDAY...THEN
LIFT TO THE NORTHEAST. OUR REGION WILL BE ON THE BACK EDGE NORTHWEST
OF THIS SYSTEM. THE 12Z GGEM/ECMWF BOTH DEVELOP THIS INTO A STRONG
COASTAL LOW...BUT KEEP ITS TRACK TO OUR SOUTHEAST. THE 12Z GFS IS
MUCH WEAKER WITH THE SYSTEM...BUT DOES CLIP SOUTHEASTERN PORTIONS OF
THE CWA WITH LIGHT QPF SATURDAY NIGHT AND SUNDAY. DESPITE THE
REMAINING MODEL DIFFERENCES...IT APPEARS LIKELY THAT THIS SYSTEM
WILL MISS WESTERN NEW YORK...BUT THERE STILL IS A CHANCE THE SYSTEM
WILL CLIP OUR REGION OR THAT THE ECMWF/GGEM WILL SHIFT WEST WITH THE
TRACK SO FORECAST WILL MAINTAIN SMALL CHANCE POPS IN SOME AREAS.
HOWEVER...THE LIKELIHOOD IS THAT SURFACE HIGH PRESSURE WILL NOSE IN
FROM THE UPPER LAKES AND BRING FAIR WEATHER TO THE REGION. EXPECT
SOME CLOUD COVER WITH THE COASTAL LOW...BUT THE NEXT BEST CHANCE FOR
AT LEAST SOME DECENT SUNSHINE IS ON SATURDAY. HIGH TEMPERATURES WILL
REMAIN ON THE COOL SIDE...RUNNING FROM THE UPPER 20S TO LOWER 30S
FOR THE WEEKEND.

LOOKING AHEAD INTO NEXT WEEK...BOTH THE 12Z GFS/ECMWF BOTH BUILD
HIGH PRESSURE INTO THE REGION WITH FAIR WEATHER LIKELY ON MONDAY. IT
LOOKS LIKE THIS RIDGE WILL HOLD UNTIL TUESDAY...THEN GUIDANCE
SUGGESTS A MORE ACTIVE PATTERN INTO NEXT WEEK. THIS COULD BRING RAIN
OR SNOW TO OUR REGION MID-WEEK...BUT IT/S IMPORTANT TO NOTE THAT
FORECAST GUIDANCE CAN CHANGE FROM RUN TO RUN THIS FAR OUT. STAY
TUNED...

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AS OF MID EVENING...RIDGING OVER THE NORTHEAST US CONTINUES TO
PRODUCE LARGE SCALE SUBSIDENCE AND AN ATTENDANT STRONG CAP OVER THE
REGION...WITH THE LOW LEVEL MOISTURE TRAPPED UNDERNEATH THIS
INVERSION REMAINING TRAPPED AND THUS UNABLE TO EFFECTIVELY MIX OUT.
THE END RESULT OF ALL THIS IS PERSISTENT IFR/MVFR STRATUS ALONG
WITH SOME AREAS OF FOG...MOST NOTABLY ACROSS THE HIGHER TERRAIN
AND AT KBUF/KIAG WHERE CONDITIONS HAVE BEEN RUNNING LIFR.

FOR THE BALANCE OF THE NIGHT...EXPECT THINGS TO REMAIN ROUGHLY
STATUS QUO FOR AT LEAST A FEW MORE HOURS...WITH CONDITIONS THEN
IMPROVING SOME ACROSS FAR WESTERN NEW YORK OVERNIGHT AS DRIER AIR
CURRENTLY SEEN SPREADING NORTHWARD ACROSS OHIO/PA TRIES TO WORK IN
AT THE LOWER LEVELS.

ON TUESDAY...LOW PRESSURE LIFTING ACROSS THE CENTRAL GREAT LAKES
WILL SPREAD A 3-6 HOUR-LONG PERIOD OF RAIN SHOWERS ACROSS THE REGION
FROM SOUTHWEST TO NORTHEAST...WITH THIS THEN FOLLOWED BY MUCH MORE
SCATTERED ACTIVITY. WIDESPREAD MVFR CONDITIONS REMAIN FORECAST AS
THE SHOWERS MOVE IN...WITH IFR REMAINING PREDOMINANT ACROSS THE
HIGHER TERRAIN.

OUTLOOK...
TUESDAY NIGHT...IFR/MVFR CONDITIONS CONTINUE WITH -SHRA/LOW CIGS.
WEDNESDAY...VFR/MVFR WITH A CHANCE OF RAIN AND SNOW SHOWERS.
WEDNESDAY NIGHT AND THURSDAY...VFR/MVFR WITH SCATTERED TO
OCCASIONALLY MORE NUMEROUS SNOW SHOWERS.
FRIDAY...MAINLY VFR WITH A CHANCE OF SNOW SHOWERS.
SATURDAY...VFR.

&&

.MARINE...
MODEST SOUTHEASTERLIES WILL CONTINUE THROUGH TUESDAY WHILE SLOWLY
VEERING A LITTLE MORE SOUTHERLY OVER TIME...THOUGH CONDITIONS ARE
EXPECTED TO REMAIN BELOW ADVISORY CRITERIA.

THE NEXT CHANCE FOR WIDESPREAD ADVISORY-WORTHY WINDS AND WAVES WILL
COME TUESDAY NIGHT THROUGH THURSDAY AS LOW PRESSURE PASSES BY OUR
NORTH AND USHERS IN A STRONGER WEST-SOUTHWESTERLY TO WESTERLY FLOW
OF COLDER AIR...BEGINNING TUESDAY NIGHT ON LAKE ERIE AND WEDNESDAY
ON LAKE ONTARIO. AT THIS JUNCTURE...IT APPEARS THAT SMALL CRAFT
ADVISORIES WILL EVENTUALLY BECOME NECESSARY FOR MUCH OF THE AREA.

&&

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

&&

$$

SYNOPSIS...JJR/ZAFF
NEAR TERM...JJR/ZAFF
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...JJR/ZAFF
MARINE...JJR







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