Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 180423
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1123 PM EST WED DEC 17 2014

.SYNOPSIS...
TEMPERATURES WILL CONTINUE TO FALL TONIGHT AS COLD AIR SPREADS
ACROSS THE LOWER GREAT LAKES. LIGHT RAIN AND SNOW SHOWERS WILL
CHANGE OVER TO SNOW THIS EVENING WITH ACCUMULATIONS LIMITED
PRIMARILY TO THE TUG HILL PLATEAU AND HIGHER ELEVATIONS OF THE
SOUTHERN TIER. SNOW WILL TAPER OFF THROUGH THURSDAY AS THE
ASSOCIATED AREA OF LOW PRESSURE SHIFTS AWAY. HIGH PRESSURE WILL
RETURN BY FRIDAY AND SATURDAY WITH DRYING CONDITIONS AND NEAR-NORMAL
TEMPERATURES.

&&

.NEAR TERM /THROUGH THURSDAY/...
SNOW IS TAPERING OFF ACROSS WESTERN NEW YORK LATE THIS EVENING WITH
THE PASSAGE OF A SHARPLY DEFINED MID/UPPER LEVEL SHORTWAVE.
NONETHELESS WITH A LINGERING SURFACE TROUGH AND PERSISTENT UPSLOPE
WESTERLY FLOW REMAIN IN IN PLACE THROUGH THE REST OF THE
NIGHT...EXPECT LIGHT SNOW SHOWERS TO PERSIST THROUGH THE NIGHT WITH
THE FOCUS BEING MAINLY ACROSS UPSLOPE AREAS/HIGHER TERRAIN EAST OF
THE LAKES WITH ACTIVITY BEING MORE SCATTERED ACROSS THE
BUFFALO-ROCHESTER CORRIDOR...PARTICULARLY AS MID-LEVEL MOISTURE/LIFT
DIMINISH BEHIND THE DEPARTING SHORTWAVE LATER TONIGHT. ACCUMULATIONS
WILL BE LIMITED TO PRIMARILY A LIGHT COATING ACROSS MUCH OF THE
FORECAST AREA WITH THE EXCEPTION OF THE AFOREMENTIONED UPSLOPE AREAS
WHERE UP TO TWO INCHES WILL BE POSSIBLE. TEMPERATURES WILL SETTLE
RIGHT AROUND THE 30 DEGREE MARK WITH UPPER 20S ACROSS HIGHER
ELEVATIONS...HOWEVER THE BRISK WIND WILL YIELD WIND CHILLS IN THE
TEENS TO LOWER 20S ACROSS THE FORECAST AREA.

ON THURSDAY THE COASTAL LOW WILL SHIFT FURTHER AWAY ACROSS THE
CANADIAN MARITIMES. BUFKIT PROFILES SHOW NEARLY ALL THE LINGERING
MOISTURE WILL BE BELOW 5KFT WITH WEAK LIFT. THE WESTERLY FLOW WILL
CONTINUE TO KEEP THE HIGHEST CHANCES FOR SNOW SOUTHEAST OF THE LAKES
IN THE HIGHER TERRAIN WITH ANOTHER INCH OR TWO POSSIBLE. ELSEWHERE
ACROSS THE NIAGARA FRONTIER...FINGER LAKES AND FAR NORTH COUNTRY
ONLY EXPECT A CHANCE OF SOME LIGHT SNOW OR FLURRIES. IF CLOUD TOP
TEMPS DO NOT REACH COLDER THAN -10C THEN THE PTYPE MAY JUST END UP
BEING SOME DRIZZLE OR FREEZING DRIZZLE. A SLACKENING PRESSURE
GRADIENT WILL STILL KEEP SOME BREEZY WINDS ACROSS THE REGION WHICH
WILL COMBINE WITH TEMPERATURES ONLY REACHING INTO THE LOW 30S TO
KEEP WIND CHILLS IN THE TEENS.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
LOW PRESSURE ACROSS THE CANADIAN MARITIMES WILL MAINTAIN AN NW FLOW
ACROSS THE REGION FOR THURSDAY NIGHT. ALOFT...THE REGION WILL REMAIN
ON THE BACK EDGE OF A CLOSED 500 MB LOW...WITH FORECAST SOUNDINGS
MAINTAINING AN INVERSION JUST BELOW 5K FEET. THIS WILL RESULT IN
MINIMAL LAKE INDUCED INSTABILITY...JUST ENOUGH TO PRODUCE VERY LIGHT
AND BARELY MEASURABLE PRECIPITATION. PROBABLY THE BIGGEST CONCERN
HERE IS THAT TEMPERATURES BENEATH THE INVERSION ARE FORECAST TO BE
AROUND -10C...WHICH IS PROBABLY JUST COLD ENOUGH FOR ICE NUCLEI TO
FORM AND KEEP PRECIPITATION AS LIGHT SNOW OR FLURRIES. IF CLOUD TOPS
ARE ANY WARMER...THEN FREEZING DRIZZLE WOULD BECOME A CONCERN SINCE
SURFACE TEMPERATURES WILL BE IN THE 20S THURSDAY NIGHT.

ON FRIDAY...HIGH PRESSURE WILL BEGIN TO NOSE IN FROM THE UPPER
LAKES...WITH WINDS DIMINISHING THROUGH THE DAY. THERE MAY BE SOME
LIGHT SNOW SHOWERS OR FLURRIES LINGERING DURING THE MORNING
HOURS...BUT EXPECT THESE TO TAPER OFF BY FRIDAY AFTERNOON. ALTHOUGH
WINDS WILL DIMINISH...THE INVERSION WILL LARGELY REMAIN IN
PLACE...WHICH SHOULD KEEPS SKIES MOSTLY CLOUDY FRIDAY AND FRIDAY
NIGHT. THIS WILL LIMIT DIURNAL TEMPERATURE VARIATION WITH HIGHS
FRIDAY IN THE UPPER 20S TO LOWER 30S. CONSIDERABLE CLOUDINESS FRIDAY
NIGHT WILL KEEP LOWS IN THE LOWER 20S IN MOST AREAS FRIDAY
NIGHT...BUT A PARTIAL CLEARING MAY ALLOW TEMPS TO DROP INTO THE
TEENS OR COLDER IN THE NORTH COUNTRY.

HIGH PRESSURE WILL BUILD ACROSS THE REGION ON SATURDAY...WITH FAIR
WEATHER ACROSS THE REGION. THE LINGERING INVERSION WILL RESULT IN
CONSIDERABLE CLOUD COVER DURING THE DAY...BUT MOISTURE BENEATH IT
WILL BE VERY SHALLOW WHICH SHOULD ALLOW FOR SOME BREAKS IN THE
CLOUDS ON SATURDAY. HIGHS WILL BE SLIGHTLY BELOW NORMAL...MOSTLY
IN THE LOWER 30S ACROSS THE REGION.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SATURDAY NIGHT THROUGH MONDAY NIGHT LOOKS RATHER UNEVENTFUL. 12Z
GFS/ECMWF/GGEM GUIDANCE CONTINUE TO BRING JUST A WEAK UPPER LEVEL
TROUGH ACROSS OUR REGION AND DO NOT PHASE THIS SHORTWAVE LIKE RUNS
EARLIER IN THE WEEK DID. THIS MAY BRING LIGHT SNOW SHOWERS OR
FLURRIES TO OUR REGION...BUT THERE IS INCREASING CONFIDENCE THAT
THERE WILL BE LITTLE IF ANY IMPACT FROM THIS SYSTEM. MOST 12Z
GUIDANCE DOES NOT EVEN BRING MEASURABLE QPF TO THE REGION.
OTHERWISE...WEAK SURFACE HIGH PRESSURE WILL DRIFT INTO NORTHERN NEW
ENGLAND...WITH PARTLY CLOUDY SKIES AND SEASONABLE TEMPERATURES.

AFTER THIS...A MUCH MORE ACTIVE WEATHER PATTERN IS LIKELY TO
DEVELOP. A CLOSED 500 MB LOW FORECAST TO BE NEAR THE GREAT LAKES
REGION TUESDAY MORNING WILL PIVOT A STRONG SHORTWAVE AROUND IT AND
SPARK STRONG LOW PRESSURE WHICH IS FORECAST TO TRACK UP THE EASTERN
STATES WRAP BACK INTO THE UPPER LOW. THIS GENERAL SCENARIO IS
SUPPORTED BY AN EXCELLENT CONSENSUS AMONG 12Z AND PREVIOUS RUNS OF
THE GFS/ECMWF. THIS WOULD RESULT IN AN ANOMALOUSLY DEEP LOW OF
AROUND 965MB ACROSS THE GREAT LAKES REGION ON WEDNESDAY.

ALTHOUGH THIS GENERAL SCENARIO IS LIKELY TO PLAY OUT...THE SPECIFIC
TRACK AND EVOLUTION OF THIS SYSTEM WILL DETERMINE OUR WEATHER...AND
THESE SPECIFICS ARE STILL UNCERTAIN. BASED ON THE CONSENSUS SOLUTION
THERE ARE A FEW CONCLUSIONS THAT CAN BE DRAWN. FIRST...THE MOST
SIGNIFICANT IMPACT FROM THIS SYSTEM IS LIKELY TO BE STRONG WINDS.
MODEL VARIABILITY MAKES IT DIFFICULT TO DETERMINE WHEN AND
WHERE...BUT STRONG TO DAMAGING WINDS MAY OCCUR IN SOME LOCATIONS
TUESDAY NIGHT AND/OR WEDNESDAY. ALSO...THE INITIAL ROUND OF
PRECIPITATION FROM THIS SYSTEM IS LIKELY TO BE RAIN ON TUESDAY NIGHT
OR WEDNESDAY. NEARLY ALL GUIDANCE HAS TEMPERATURES WELL TOO WARM TO
SUPPORT SNOW INITIALLY. SO AS IT STANDS NOW...CHRISTMAS EVE LOOKS TO
BE A RAINY AND WINDY DAY...WITH ABOVE NORMAL TEMPERATURES.

LOOKING A BIT FURTHER...TEMPERATURES SHOULD COOL CHRISTMAS DAY AND
BEYOND. THIS WILL PROBABLY CHANGE OVER PRECIPITATION TO SNOW BUT
SIGNIFICANT...OR ANY...ACCUMULATION IS STILL HIGHLY UNCERTAIN. THE
MOST NOTABLE WEATHER FEATURE FOR CHRISTMAS DAY MAY AGAIN BE STRONG
WINDS...WITH CONSENSUS GUIDANCE STALLING THE STRONG LOW NEAR THE
UPPER LAKES. AGAIN...IT IS IMPORTANT TO NOTE THAT MODEL GUIDANCE IS
LIKELY TO VARY FROM RUN TO RUN...AND SIGNIFICANT SHIFTS IN THE TRACK
AND POSITION OF THE LOW ARE STILL VERY POSSIBLE WITH THE FORECAST
STILL A WEEK AWAY.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AN AREA OF -SN ASSOCIATED WITH A PASSING UPPER LEVEL DISTURBANCE
BROUGHT A PERIOD OF IFR CONDITIONS TO WNY OVER THE LAST 2
HOURS...HOWEVER THIS ACTIVITY IS NOW TAPERING OFF AS THE SHORTWAVE
TROUGH MOVES PAST THE AREA. EXPECT MAINLY MVFR CONDITIONS TO PERSIST
THROUGH THE REST OF THE NIGHT...WITH IFR ACROSS THE HIGHER
ELEVATIONS...AS SURFACE TROUGHING WILL LINGER ACROSS THE AREA. THERE
IS STILL A POTENTIAL EVEN FOR PRECIP TO CHANGE OVER TO -FZDZ IN THE
06Z-09Z TIME FRAME AS MID-LEVEL LIFT/MOISTURE DIMINISH IN THE WAKE OF A
PASSING UPPER LEVEL DISTURBANCE...HOWEVER SATURATION WILL NEAR
ENOUGH TO THE DENDRITIC GROWTH ZONE THAT PRECIP MAY STAY IN THE FORM
OF -SHSN. EITHER WAY...PRECIP WILL BE VERY LIGHT AS MID-LEVEL
MOISTURE IS STRIPPED OUT. OTHERWISE...EXPECT MVFR CIGS TO PERSIST
THROUGH THE DAY ON THURSDAY AS LOW LEVEL MOISTURE WILL ONCE AGAIN
REMAIN TRAPPED UNDER A STEEPENING INVERSION AROUND 3KFT.

OUTLOOK...
THURSDAY NIGHT...CHANCE OF LIGHT SNOW SHOWERS MAINLY EAST OF THE
LAKES AND MVFR.
FRIDAY...MVFR TO VFR WITH CHANCES OF SNOW SHOWERS ENDING. SATURDAY
TO MONDAY...VFR.
TUESDAY...VFR/MVFR WITH A CHANCE OF RAIN SHOWERS.

&&

.MARINE...
A COASTAL LOW WILL SHIFT NORTH ACROSS THE GULF OF MAINE TONIGHT. THE
SURFACE PRESSURE GRADIENT ACROSS THE LOWER GREAT LAKES ALONG WITH
COLD ADVECTION WILL MAINTAIN BRISK WESTERLY WINDS...WHICH WILL IN
TURN CONTINUE TO BRING SMALL CRAFT ADVISORIES CONDITIONS ON BOTH
LAKES AS WELL AS THE UPPER NIAGARA RIVER TONIGHT. WINDS AND WAVES
WILL GRADUALLY SUBSIDE THURSDAY INTO THURSDAY EVENING AS LOW
PRESSURE MOVES AWAY FROM THE AREA AND HIGH PRESSURE BUILDS INTO THE
LOWER GREAT LAKES. THIS WILL USHER IN A PERIOD OF MORE TRANQUIL
CONDITIONS ON THE LAKES FOR FRIDAY AND THE WEEKEND.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THURSDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LEZ020.
         SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR
         LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 10 PM EST THURSDAY FOR LOZ042.

&&

$$

SYNOPSIS...SMITH/WOOD
NEAR TERM...SMITH/WOOD
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...WOOD
MARINE...WOOD







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