Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 180822
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
322 AM EST THU DEC 18 2014

.SYNOPSIS...
LOW LEVEL MOISTURE AND A SURFACE TROUGH ACROSS THE REGION WILL
PRODUCE SOME LIGHT SNOW TODAY AND TONIGHT. HIGH PRESSURE WILL RETURN
BY FRIDAY AND SATURDAY WITH DRYING CONDITIONS AND NEAR-NORMAL
TEMPERATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
LOW PRESSURE WELL TO THE EAST OF THE FORECAST AREA IS HAVING A
LESSENING EFFECT ON THE SENSIBLE WEATHER ACROSS WESTERN AND NORTHERN
NEW YORK. THE SURFACE LOW IS OVER THE CANADIAN MARITIMES AND AN
EXTENSIVE SURFACE AND UPPER TROUGH REACHES TO THE WEST OF THE
LOW...BACK TO THE CENTRAL GREAT LAKES. EARLIER DURING WEDNESDAY
NIGHT THERE WAS ALSO AN EXTENSIVE AREA OF GENERALLY LIGHT SNOW
ASSOCIATED WITH THIS SURFACE TROUGH AS A MID TO UPPER LEVEL WAVE
PASSED EASTWARD WITH A BROAD REGION OF LIFT. RADAR AND SATELLITE
SHOW THIS REGION OF LIFT...COLDER CLOUD TOPS...HAS MOVED ACROSS
EASTERN NEW YORK AS OF 08Z WITH LITTLE TO THE WEST. CLOUD TOPS
ACROSS THE FORECAST AREA AND UPSTREAM ACROSS THE CENTRAL GREAT LAKES
ARE -12C TO -14C WHICH SHOULD BE COLD ENOUGH TO FORM SEEDING
CRYSTALS ALOFT FOR LIGHT SNOW BELOW. ADDITIONAL LIFT FROM A BROAD
REGION OF CYCLONIC TURNING ALONG THE SURFACE TROUGH AND LOW LEVEL
OROGRAPHIC LIFT SHOULD PROVIDE ENOUGH BOOST TO MAINTAIN LIGHT SNOW
ACROSS THE REGION TODAY AND TONIGHT...ESPECIALLY THE HILLS OF THE
SOUTHERN TIER AND TUG HILL PLATEAU REGIONS.

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 MIDDLE TEENS TO MIDDLE
20S. UNDER CONTINUED AND PERSISTENT COLD AIR ADVECTION...LOW TEMPS
TONIGHT FALL ANOTHER NOTCH WITH READINGS IN THE TEENS EAST OF LAKE
ONTARIO AND THE MIDDLE 20S OVER THE REST OF FORECAST AREA.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL BUILD STEADILY INTO THE REGION FRIDAY...
EVENTUALLY CENTERING ITSELF ACROSS THE AREA BY SATURDAY. THERE MAY
BE SOME LIGHT SNOW SHOWERS OR FLURRIES LINGERING DURING THE MORNING
HOURS...BUT EXPECT THESE TO TAPER OFF BY FRIDAY AFTERNOON. MODEL
SOUNDINGS/CROSS-SECTION MOISTURE ANALYSIS CONTINUES TO SUPPORT LOW
CLOUDS HANGING ON FOR MUCH OF WESTERN AND NORTH CENTRAL NEW YORK
FRIDAY AND FRIDAY NIGHT...WITH COOLING BOUNDARY LAYER AND STRONG
SUBSIDENCE INVERSION LOCKING IN STRATUS DURING THIS TIME.

INCREASINGLY DRIER PROFILES DURING SATURDAY SHOULD EVENTUALLY BRING
AT LEAST PARTIAL SUNSHINE TO THE AREA. THE MOST SUNSHINE WILL LIKELY
BE FOUND ACROSS THE SAINT LAWRENCE RIVER VALLEY AND THE NORTH
COUNTRY.

TEMPERATURES LOOK TO BE NEAR SEASONAL READINGS FOR THIS TIME OF THE
YEAR...WITH HIGHS GRADUALLY MODERATING FROM THE MID 20S/LOWER 30S
FRIDAY TO THE LOWER/MID 30S SATURDAY. OVERNIGHT LOWS MOSTLY IN THE
TEENS AND 20S.

&&

.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 /09Z 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...
WINDS AND WAVES WILL GRADUALLY SUBSIDE TODAY INTO THIS EVENING AS
LOW PRESSURE MOVES FARTHER EAST AND 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 THIS EVENING FOR LEZ040-
         041.
         SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR
         LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
         LOZ042.

&&

$$

SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...TMA
LONG TERM...APFFEL
AVIATION...WOOD
MARINE...WCH







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