Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 291211
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
711 AM EST MON DEC 29 2014

.SYNOPSIS...
A WEAK SURFACE TROUGH WILL CROSS THE LOWER GREAT LAKES TODAY WITH
LAKE EFFECT CLOUDS AND A CHANCE FOR FLURRIES AND LIMITED SNOW
SHOWERS. COOLER AIR WILL ARRIVING BEHIND THE TROUGH WILL CONTINUE TO
HELP IT FEEL MUCH MORE LIKE MID- WINTER THROUGH MUCH OF THE WEEK.
BETTER CHANCES FOR LAKE EFFECT SNOW ARRIVE BY LATE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS SUPPORTED BY SATELLITE AND RADAR IMAGERY SHOW A
WEAKENING COLD FRONT/SURFACE TROUGH IS SETTLING SOUTH ACROSS WESTERN
NEW YORK THIS MORNING. THE LEADING EDGE OF CLOUDINESS WITH SOME
LIGHT SNOW SHOWERS/FLURRIES WILL WORK SOUTH THROUGH THE MORNING
HOURS WITH MOST LOCATIONS OVERCAST THROUGH THE MORNING. KTYX RADAR
RADAR SHOWING A WEAK BAND OF LAKE EFFECT SNOW ALONG THE
SOUTHEAST SHORELINE OF LAKE ONTARIO PUSHING SOUTH JUST AHEAD OF THE
SURFACE TROUGH.

THROUGH TODAY THE SURFACE TROUGH WILL CONTINUE TO SAG SOUTH ACROSS
WESTERN AND CENTRAL NEW YORK WHILE WEAKENING. COLD NORTHWEST FLOW
BEHIND THE BOUNDARY WILL KEEP LAKE EFFECT STRATOCU IN PLACE ACROSS
MUCH OF WESTERN NEW YORK INTO THE AFTERNOON WITH LOW CHANCES FOR
SOME EMBEDDED SNOW FLURRIES. THE ENHANCED FLOW AND CONVERGENCE ON
THE SOUTHWEST SHORE OF LAKE ONTARIO WILL CONTINUE A BIT HIGHER SNOW
PROBS FROM WAYNE TO OSWEGO COUNTY TODAY AS 850MB TEMPERATURES FALL
DOWN TO AROUND -15C. THIS WILL FORCE SURFACE TEMPERATURES TO SLOWLY
FALL THROUGH THE UPPER 20S TODAY INTO THE LOW 20S OR EVEN TEENS
ACROSS THE SOUTHERN TIER AND NORTH COUNTRY TONIGHT. LAKE EFFECT
CLOUDS AND WEAK SNOW SHOWERS WILL CONTINUE TO BE POSSIBLE ACROSS THE
SOUTHEAST LAKE ONTARIO REGION OVERNIGHT.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
CHILLY WEST-NORTHWEST FLOW WILL DOMINATE ON TUESDAY AS THE REGION
WILL BE LOCATED UNDERNEATH THE EASTERN FRINGE OF AN EXPANSIVE ARCTIC
HIGH THAT WILL BE CENTERED OVER THE NORTHERN PLAINS...BUT
ENCOMPASSING A SIGNIFICANT PORTION OF THE COUNTRY. WITH 850 TEMPS
DROPPING TO AROUND -16C...THIS COLD NORTHWEST FLOW SHOULD BE MORE
THAN SUFFICIENT TO GENERATE A ROBUST LAKE RESPONSE...HOWEVER THE
ARCTIC AIRMASS ADVECTING ACROSS THE LAKES WILL BE VERY DRY AND WITH
LARGE SCALE SUBSIDENCE ASSOCIATED WITH THE HIGH...EQUILIBRIUM LEVELS
WILL ONLY BE RUNNING AROUND 5KFT AND THIS COMBINED WITH THE
GENERALLY SHORT FETCH ACROSS THE LAKES WILL ONLY BE ENOUGH TO
GENERATE WIDESPREAD CLOUD COVER AND SCATTERED FLURRIES ACROSS THE
FORECAST AREA TUESDAY. THE ONE EXCEPTION WILL BE IN THE ST. LAWRENCE
VALLEY WHERE THE NORTHWEST FLOW OUT OF QUEBEC SHOULD YIELD A DECENT
AMOUNT OF SUNSHINE. WITH THE ARCTIC AIR FLOWING FREELY...HIGHS WILL
ONLY TOP OUT IN THE MID 20S.

AS WE MOVE INTO TUESDAY NIGHT...LOW-LEVEL FLOW WILL BACK TO THE WEST
AND BECOME BETTER ALIGNED WITH UPPER LEVEL FLOW AS A WELL-DEFINED
UPPER LEVEL TROUGH DROPS ACROSS THE GREAT LAKES. THE INCREASING
DOWN-LAKE FETCH COUPLED WITH SYNOPTIC LIFT FROM THE AFOREMENTIONED
SHORTWAVE SHOULD PRODUCE A DECENT LAKE RESPONSE EAST OF LAKE ONTARIO
AS THE EQUILIBRIUM LEVEL APPROACHES 10KFT AND ADVISORY LEVEL SNOWS
ARE NOT OUT OF THE QUESTION ON THE TUG AS WE MOVE FROM TUESDAY NIGHT
INTO WEDNESDAY MORNING. MOISTURE WILL BE SHALLOWER AND LESS ABUNDANT
EAST OF LAKE ERIE...NONETHELESS GIVEN STRONG...ALBEIT
SHALLOW...INSTABILITY AND REASONABLY WELL-ALIGNED WESTERLY/UPSLOPE
FLOW...SUSPECT WE WILL SEE A HIGH POP/LOW QPF EVENT WITH WIDESPREAD
VERY LIGHT LES PRODUCING ONLY SLIGHT ACCUMULATIONS...ON THE ORDER OF
A HALF INCH OR SO TUESDAY NIGHT INTO WEDNESDAY MORNING. LOOK FOR
LOWS IN THE TEENS...THOUGH THE WESTERLY BREEZE WILL PUSH WIND CHILLS
DOWN INTO THE LOW SINGLE DIGITS ABOVE ZERO.

THE CONTINUED PRESENCE OF ARCTIC AIR COUPLED WITH STRENGTHENING
BACKED SOUTHWESTERLY FLOW AHEAD OF A DEEP MID-LEVEL TROUGH WILL MAKE
FOR A CHILLY NEWS YEAR`S EVE ACROSS THE REGION. WITH THE BACKING
FLOW...LOOK FOR LES TO SHIFT FROM THE TUG TO THE THOUSAND ISLANDS
REGION THROUGH THE DAY WEDNESDAY INTO WEDNESDAY NIGHT. IN
FACT...ADVISORY LEVEL SNOWS ARE NOT OUT OF THE QUESTION FOR THE
SAINT LAWRENCE VALLEY WEDNESDAY NIGHT AS ANY LAKE ONTARIO BAND WOULD
BENEFIT FROM AN UPSTREAM CONNECTION TO LAKE ERIE. LIKEWISE...LOOK
FOR LIMITED SHOWER ACTIVITY TO SHIFT FROM THE WESTERN SOUTHERN TIER
INTO THE BUFFALO METRO AS WE MOVE INTO NEW YEAR`S EVE...THOUGH ONCE
AGAIN IT WILL BE MUCH MORE LIMITED IN SCOPE AND INTENSITY OWING TO A
DEARTH OF DEEPER MOISTURE ALOFT AS COMPARED TO EAST OF LAKE ONTARIO.

AS ELUDED TO ABOVE...WINDS WILL BE BACKING TO THE SOUTHWEST AND
STRENGTHENING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE ARCTIC
HIGH...NOW BEING SQUEEZED AND PUSHED INTO THE SOUTHERN HALF OF THE
COUNTRY...AND A LARGE SURFACE TROUGH DIPPING ACROSS ONTARIO/QUEBEC.
THE RESULTANT SOUTHWESTERLY FLOW MAY FRESHEN ENOUGH TO GENERATE NEAR
GALE-FORCE WINDS ON THE LAKES...WITH POTENTIAL LOW-END ADVISORY
LEVEL WINDS ACROSS THE NIAGARA FRONTIER WEDNESDAY NIGHT. NEEDLESS TO
SAY...THIS WOULD PUT A DAMPER ON NEW YEAR`S EVE CELEBRATIONS AS WIND
CHILLS MAY DIP INTO SUB-ZERO RANGE.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
CYCLONIC UPPER LEVEL FLOW AND COLD TEMPERATURES WILL PERSIST AT
LEAST THROUGH THURSDAY NIGHT...AND AS A RESULT LAKE EFFECT SNOWS
WILL LINGER THROUGH THURSDAY NIGHT. ANY REMAINING ACTIVITY WILL SHIFT
BACK TOWARDS THE TUG AND SOUTHERN TIER THURSDAY NIGHT AS FLOW ONCE
AGAIN VEERS TO THE WEST. UNCERTAINTY REIGNS AFTER THURSDAY NIGHT AS
THE MODELS ARE VERY MUCH AT ODDS REGARDING THE UNFOLDING OF A
SCENARIO THAT INVOLVES THE PHASING OF A CUTOFF LOW OVER THE SOUTHWEST
WITH NORTHERN STREAM UPPER LEVEL ENERGY AND SUBSEQUENT CYCLOGENESIS
OVER THE CENTRAL UNITED STATES. FOR WHAT IT`S WORTH THE 00Z ECMWF
AND GLOBAL GEM MODELS FAVOR A MORE SEQUESTERED CUTOFF LOW THAT KEEPS
THE BULK OF THE WARM MOIST AIR AND ASSOCIATED PRECIPITATION SOUTH OF
THE OHIO VALLEY WHILE KEEPING COLD AND DRY AIR LOCKED IN OVER THE
GREAT LAKES. THE GFS IS THE OUTLIER IN PHASING THE NORTHERN AND
SOUTHERN STREAM ENERGY...YIELDING A RAPIDLY DEEPENING CUTTER LOW
THAT WOULD YIELD A WARM AND WET FORECAST FOR NEXT WEEKEND. AT THIS
POINT AM MORE INCLINED TO FOLLOW THE MORE REASONABLE ECMWF
SOLUTION...BUT WILL LEAVE CHANCE POPS IN PLACE TO ACCOUNT FOR THE
CONSIDERABLE UNCERTAINTY. LIKEWISE...THE TEMPERATURE FORECAST WILL
STRADDLE THE MIDDLE GROUND BETWEEN THE TWO VERY DIFFERENT SOLUTIONS
WITH HIGHS RUNNING CLOSE TO CLIMATOLOGY FRIDAY THROUGH SUNDAY...IN
THE 30S...WITH LOWS IN THE 20S.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A WEAK SURFACE TROUGH IS CROSSING THE REGION THIS MORNING. SHALLOW
MOISTURE AND WEAK LIFT IS BRINGING OVC SKIES BUT EXPECT CIGS TO
REMAIN VFR WITH LOW CHANCES OF SNOW FLURRIES THROUGH MUCH OF TODAY
AND TONIGHT. A WEAK BAND OF LAKE EFFECT WILL CONTINUE SOUTHEAST OF
LAKE ONTARIO REMAINING BETWEEN KROC AND KART UNDER A SOUTHWEST FLOW.
OVERALL TIMING/AREAL CONFIDENCE FOR ANY OTHER WEAK -SNSH IS TOO LOW
FOR INCLUSION IN THE TAFS AT THIS TIME. SOME BREAKS IN CIGS MAY
DEVELOP THIS AFTERNOON/EVENING THEN STILL COLDER AIR ARRIVING LATER
TONIGHT WILL BRING A RETURN OF BKN/OVC CIGS WITH A CHANCE FOR LAKE
EFFECT SNOW SHOWERS ALONG THE SOUTHERN LAKE ONTARIO SHORELINE.

OUTLOOK...
TUESDAY...VFR/MVFR CIGS.
WEDNESDAY THROUGH FRIDAY...POSSIBLE IFR IN WSW LAKE EFFECT
-SHRA...MVFR/VFR ELSEWHERE.

&&

.MARINE...
ARCTIC HIGH PRESSURE BUILDING OVER THE GREAT LAKES WILL HELP TO
BRING MORE RELAXED WINDS AND SUBSIDING WAVES TODAY. THE RELATIVELY
LIGHT NORTHWEST WINDS WILL CONTINUE THROUGH TUESDAY BEFORE WINDS
BACK TO THE SOUTHWEST ON WEDNESDAY AND STRENGTHEN AGAIN AHEAD OF
ANOTHER LOW DROPPING OUT OF THE CANADIAN ARCTIC. THIS WILL
POTENTIALLY BRING GALE FORCE WINDS BY WEDNESDAY NIGHT AND THURSDAY.

&&

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

&&

$$

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







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