Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 292010
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
410 PM EDT WED OCT 29 2014

.SYNOPSIS...
COOL AIR FLOWING INTO THE REGION WILL GENERATE SOME LAKE EFFECT RAIN
SHOWERS EAST OF THE LAKES TONIGHT AND THURSDAY. A LOW PRESSURE
SYSTEM IS EXPECTED TO CROSS THE AREA FRIDAY AND SATURDAY...USHERING
IN COLD CONDITIONS FOR THE COMING WEEKEND. RAIN ASSOCIATED WITH THIS
SYSTEM WILL POTENTIALLY TRANSITION INTO THE FIRST SNOWFLAKES OF THE
SEASON BY SATURDAY MORNING.

&&

.NEAR TERM /THROUGH THURSDAY/...
COLD AIR ADVECTION CONTINUING ACROSS THE REGION THIS AFTERNOON WITH
850 MB TEMPERATURES FALLING FROM +1C THIS MORNING TO NEAR -1C THIS
AFTERNOON. THIS IS JUST COLD ENOUGH TO GENERATE A WEAK BAND RAIN
SHOWERS EAST OF LAKE ERIE...BASICALLY BETWEEN DUNKIRK AND
BUFFALO. EXPECT A SIMILAR BAND TO BEGIN TO FORM EAST OF LAKE
ONTARIO BETWEEN 20Z AND 23Z AS COLDER AIR WORKS INTO THAT PORTION
OF THE AREA.

UPPER SHORT WAVE CURRENTLY SEEN WORKING THROUGH THE CENTRAL LAKES
WILL PUSH SOUTHEASTWARD INTO THE AREA TONIGHT. THIS WILL THE LOW
LEVEL FLOW TO NORTHWESTERLY AND WITH UPSTREAM SOUNDINGS SUGGESTING
THAT -2C TO -4C AIR WILL INVADE THE AREA OVERNIGHT. THIS WILL HELP
TO MAINTAIN THE LAKE EFFECT RAIN SHOWER ACTIVITY TO THE SOUTHEAST OF
THE LAKES INTO THURSDAY MORNING. LOWS TONIGHT WILL DROP OFF TO THE
30S...WITH A FEW AREAS SOUTHEAST OF LAKE ONTARIO REMAINING IN THE
LOWER 40S.

THURSDAY...LOW TO MID LEVELS BEGIN TO DRY OUT AS WEAK UPSTREAM RIDGE
EASES INTO THE EASTERN GREAT LAKES AND LOW LEVEL FLOW WEAKENS AND
BEGINS TO BACK MORE WESTERLY DURING THE COURSE OF THE DAY. ANY WEST
NORTHWEST FLOW LAKE EFFECT RAIN SHOWERS START TO WIND DOWN AS EARLY
AS MIDDAY WITH A MUCH GREATER DECREASE IN COVERAGE BY THE AFTERNOON.
SOME VERY LIMITED SUNSHINE FOR AREAS OUTSIDE OF THE LAKE EFFECT
ACTIVITY WILL LIKELY DO LITTLE TO HELP TEMPERATURES AS A COLD
AIRMASS SETTLES OVER THE REGION. HIGHS LOOK TO BE MAINLY IN THE MID
TO UPPER 40S.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS WE OPEN THE PERIOD THURSDAY NIGHT...THE FOCUS WILL BE ON A POTENT
UPPER LEVEL SHORTWAVE THAT WILL BE DIVING ACROSS THE UPPER GREAT LAKES OUT
OF WESTERN ONTARIO. HOWEVER THIS WILL NOT BE YOUR TYPICAL CLIPPER AS
FLOW ACROSS NORTH AMERICA WILL BE HIGHLY MERIDIONAL AND INFLUENCED BY
STEEP RIDGING ACROSS THE INTER-MOUNTAIN WEST. THE PROSPECTS FOR
SEEING ACCUMULATING SNOWS ACROSS MUCH OF WESTERN OR NORTH-CENTRAL
NEW YORK THIS WEEKEND ARE LOOKING DIMMER AS THE LATEST MODEL
CONSENSUS INDICATES THAT THIS UPPER LOW WILL TAKE A SLIGHTLY MORE
WESTERLY TRACK ACROSS THE OHIO VALLEY FRIDAY AND FRIDAY NIGHT...AS
COMPARED TO YESTERDAY`S TRACK ACROSS CENTRAL WEST VIRGINIA. THIS
SUBTLE DIFFERENCE WILL HAVE THE EFFECT OF PLACING WESTERN AND
CENTRAL NEW YORK UNDER GREATER INFLUENCE OF MILDER MARITIME AIR
FLOWING OFF THE ATLANTIC DURING THE PERIOD OF GREATEST PRECIPITATION
POTENTIAL FRIDAY AND FRIDAY NIGHT WITH 850MB TEMPS NOW RUNNING
AROUND -2C...AS OPPOSED TO EARLIER RUNS THAT WERE MORE AGGRESSIVE ON
BRINGING COLDER ARCTIC AIR INTO THE LOWER GREAT LAKES.

WITH THE UPPER LEVEL TROUGH OVER THE WESTERN GREAT LAKES AND
ATTENDANT SURFACE LOW LOCATED JUST TO OUR NORTHWEST...EXPECT
THURSDAY NIGHT TO REMAIN DRY WITH TEMPERATURES RUNNING NEAR
CLIMATOLOGICAL AVERAGES WITH LOWS IN THE MID TO UPPER 30S.
PRECIPITATION CHANCES THEN RAMP UP DURING THE DAY ON FRIDAY AS THE
SHORTWAVE CLOSES OFF INTO AN COMPACT UPPER LOW CENTER OVER WESTERN
OHIO AND WESTERN NEW YORK COMES UNDER THE INFLUENCE OF A COMBINATION
OF UPPER LEVEL DIFFLUENCE AND MODEST SURFACE CONVERGENCE WITH ANY
PRECIPITATION FALLING AS RAIN SINCE TEMPERATURES WILL BE RUNNING
WELL INTO THE 40S.

AS MENTIONED ABOVE...IT NOW APPEARS THAT MILDER MARITIME AIR WILL
LINGER ACROSS THE FORECAST AREA LONG ENOUGH TO PRECLUDE THE
DEVELOPMENT OF SNOW ACROSS MUCH OF THE REGION THROUGH FRIDAY NIGHT.
EVEN THOUGH TEMPERATURES WILL CERTAINLY BE SUB-FREEZING...LOW LEVEL
READINGS APPEAR TO BE JUST ENOUGH ABOVE FREEZING...AND MORE
IMPORTANTLY SURFACE DEWPOINTS ARE NOW ALSO EXPECTED TO REMAIN FAR
ENOUGH ABOVE FREEZING SUCH THAT IT WILL BE VERY DIFFICULT FOR
DYNAMIC COOLING PROCESSES TO PUSH THE WET BULB ZERO TEMPERATURE TO
THE SURFACE...A NECESSARY PRE-REQUISUTE FOR ACCUMULATING SNOWS.
NONETHELESS...IT IS STILL CLOSE ENOUGH TO WARRANT LEAVING AT LEAST A
RAIN-SNOW MIX IN ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER FOR
NOW ON FRIDAY NIGHT INTO SATURDAY MORNING WITH ANY ACCUMULATIONS
LIKELY AMOUNTING TO NOT MUCH MORE THAN A COATING OF WET SNOW. AS FOR
THE EASTERN HALF OF THE FORECAST AREA...WILL CARRY ONLY CHANCE POPS
THROUGH THE PERIOD AS THE AREA WILL LARGELY ESCAPE THE DEEPER
SYNOPTIC MOISTURE AND FORCING AND ALSO WILL NOT BE SUBJECT TO LAKE
INFLUENCES DUE TO THE PREVAILING NORTH-NORTHEAST FLOW. AS WITH
THURSDAY NIGHT...TEMPERATURES WILL BE HOVERING IN THE MID TO UPPER
30S.

THE RACE ON SATURDAY WILL BE BETWEEN DEEPER SYNOPTIC MOISTURE THAT
WILL BE DEPARTING THE REGION AS OUR UPPER LEVEL SYSTEM MOVES OFF THE
EAST COAST AND COLDER AIR FILTERING SOUTH FROM CANADA AS NORTHERLY
FLOW DEVELOPS ACROSS THE LOWER GREAT LAKES IN THE WAKE OF THE
DEPARTING LOW. THIS NORTHERLY FLOW WILL GENERATE LIMITED LAKE EFFECT
SHOWERS ACROSS WESTERN NEW YORK..WITH THE LIMITING FACTORS BEING
SHORT FETCH ACROSS THE LATITUDINAL AXIS OF THE LAKE AND AN INCREASING
DEARTH OF MOISTURE ALOFT. WHILE ME WAY SEE A RAIN/SNOW MIX ACROSS
THE HIGHER ELEVATIONS OF THE SOUTHERN TIER...LOWER ELEVATIONS SHOULD
STAY JUST WARM ENOUGH FOR PRECIPITATION TO FALL ENTIRELY AS A COLD
RAIN...WITH PERHAPS A FEW FLAKES MIXING IN SATURDAY EVENING AS
TEMPERATURES NEAR THE FREEZING MARK. HOWEVER...AT THAT POINT THE
MID-LEVELS WILL BE DRYING TO THE POINT THAT PRECIPITATION SHOULD BE
WINDING DOWN. WITH COLD AND DRY AIR DESCENDING ACROSS THE REGION
FROM THE NORTH...WINTER`S CHILL WILL BE FELT ACROSS THE FORECAST
AREA WITH LOWS DROPPING INTO THE 20S INLAND FROM THE LAKES...WITH
READINGS RUNNING IN THE LOWER 30S NEAR THE LAKES.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
WHILE THE NEW ENGLAND COAST MAY STILL BE DEALING WITH THE EFFECTS OF
A DEEP COASTAL LOW SUNDAY...WESTERN AND NORTH-CENTRAL NEW YORK WILL
BE ENTERING A PERIOD OF BENIGN WEATHER AS A STEEP RIDGE OVER THE
CENTRAL UNITED STATES TRANSLATES ACROSS THE GREAT LAKES. COOL
NORTHWESTERLY FLOW ON THE FRONT SIDE OF THE RIDGE WILL KEEP
CONDITIONS COOL AND CLOUDY ON SUNDAY AS LAKE EFFECT CLOUDINESS WILL
LINGER ACROSS THE REGION. HOWEVER AS WE MOVE INTO MONDAY...THE
REGION SHOULD SEE A SIGNIFICANT MODERATION IN TEMPERATURES AS THE
UPPER LEVEL RIDGE MOVES OVERHEAD AND THE SURFACE HIGH SLIDES TO THE
EAST COAST...OPENING UP THE LOWER GREAT LAKES TO WARM SOUTHERLY
RETURN FLOW. ALAS THE MILD WEATHER WILL COME AT A PRICE AS WARM
ADVECTION ALOFT WILL GENERATE A DECENT AMOUNT OF MID/HIGH
CLOUDS...PARTICULARLY ACROSS WESTERN NEW YORK.

THE PROGRESSIVE PATTERN WILL CONTINUE AS WE MOVE DEEPER INTO NEXT
WEEK AS THE UPPER LEVEL RIDGE MOVES TO THE EAST COAST AND THE NEXT
LOW PRESSURE SYSTEM TAKES AIM AT THE GREAT LAKES. MODELS ARE
CURRENTLY IN VERY GOOD AGREEMENT REGARDING THE UPPER LEVEL TROUGH AS
IT LIFTS ACROSS THE NORTHERN ROCKIES ACROSS THE UPPER MIDWEST SUNDAY
NIGHT THROUGH MONDAY NIGHT. A SHARP SURFACE FRONTAL BOUNDARY WILL
DEVELOP AS LOW LEVEL THERMAL GRADIENTS TIGHTEN ACROSS THE
NATION`S MID-SECTION AS WARM AND MOIST SOUTHERLY RETURN FLOW ACROSS
THE EASTERN U.S. ENCOUNTERS MILDER PACIFIC AIR ADVECTING SOUTHEAST
OUT OF THE NORTHERN PLAINS OVER THE TOP OF HIGH PRESSURE IN THE
GREAT BASIN. TUESDAY COULD END UP BEING A VERY MILD DAY ACROSS
THE LOWER GREAT LAKES...WITH SOME LOCATIONS POTENTIALLY CLIMBING
INTO THE LOWER 60S AS WARM AIR SURGES POLEWARD ACROSS THE REGION IN
ADVANCE OF THE AFOREMENTIONED APPROACHING COLD FRONT...CURRENTLY
PROGGED TO MOVE INTO WESTERN NEW YORK NEAR THE END OF OUR FORECAST
PERIOD...TUESDAY EVENING.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
A COOL WEST SOUTHWEST FLOW WILL DEVELOP A BAND OF LAKE EFFECT
RAIN SHOWERS OFF LAKE ERIE THROUGH TONIGHT. THIS ACTIVITY MAY
BRUSH BY THE KBUF AIRFIELD...FOR WHICH A VCSH WILL BE IN PLACE FOR
THIS AFTERNOON. BEHIND A SHORTWAVE WINDS WILL VEER AROUND TO WEST-
NORTHWEST WITH THE LAKE EFFECT RAIN BAND OFF LAKE ERIE DROPPING
SOUTHWARD...AND TOWARDS THE SOUTHERN TIER.

OFF LAKE ONTARIO EXPECT A BAND OF RAIN SHOWERS TO FORM...BUT
LIKELY NOT UNTIL TOWARD THIS EVENING AS SOUTHWESTERLY WINDS ALIGN.
THIS BAND LIKEWISE WILL DROP SOUTHWARD ACROSS AREAS EAST OF LAKE
ONTARIO THROUGH THE OVERNIGHT TIME PERIOD.

CIGS WILL LARGELY BE VFR THROUGH THE TIME PERIOD...THOUGH SOME
INSTANCES OF MVFR WILL BE LIKELY...ESPECIALLY WITHIN ANY LAKE EFFECT
RAIN BANDS. THESE BANDS OF LAKE EFFECT RAIN WILL DIMINISH IN
INTENSITY THROUGH THE OVERNIGHT AS INVERSION HEIGHTS DROP...AND LOW
LEVEL CONVERGENCE WEAKENS.

BY LATE TONIGHT SOME IFR CIGS ARE POSSIBLE ACROSS THE SOUTHERN TIER
AS LOW LEVEL SYNOPTIC MOISTURE...COMBINED WITH MOISTURE FROM LAKE
EFFECT RAIN FORM LOWER CEILINGS ACROSS THE HIGHER TERRAIN OF THE
SOUTHERN TIER. CONFIDENCE IN THIS OCCURRING IS LOW.

OUTLOOK...
THURSDAY...MAINLY VFR...EXCEPT MVFR WITH A CHANCE OF SHOWERS
DOWNWIND OF THE LAKES.
FRIDAY...VFR/MVFR WITH RAIN SHOWERS BECOMING LIKELY FRIDAY...WITH
FURTHER DETERIORATION TO IFR/MVFR AS THE PRECIPITATION CHANGES OVER
TO SNOW SHOWERS FRIDAY NIGHT.
SATURDAY...MVFR/IFR WITH SCATTERED TO NUMEROUS SNOW SHOWERS.
SUNDAY AND MONDAY...MAINLY VFR.

&&

.MARINE...
DEEP LOW PRESSURE IN THE VICINITY OF JAMES BAY WILL ADVANCE ACROSS
NORTHERN QUEBEC PROVINCE TONIGHT AND THURSDAY. BRISK WESTERLY WINDS
OF THE BACK SIDE OF THIS LOW WILL MAINTAIN ADVISORY LEVEL CONDITIONS
ON THE LAKES INTO THIS EVENING.

TONIGHT AND THURSDAY...WINDS WILL VEER TO NORTHWESTERLY AND PRODUCE
AN EXTENDED PERIOD OF ADVISORY LEVEL WINDS AND WAVES ACROSS THE
LOWER LAKES.

THE PRESSURE GRADIENT WILL RELAX ACROSS THE LOWER LAKES AS WEAK LOW
PRESSURE PUSHES INTO THE REGION THURSDAY NIGHT AND FRIDAY. THE
ENERGY FROM THIS LOW WILL COMBINE WITH A COASTAL LOW TO FORM A DEEP
NORTHEAST COASTAL STORM OVER THE WEEKEND. STRENGTHENING NORTHERLY
COMPONENT WINDS ON THE WESTERN SIDE OF THE COASTAL LOW WILL BRING
ADVISORY LEVEL CONDITIONS BACK TO THE LOWER LAKES OVER THE WEEKEND.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         LEZ020.
         SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR
         LOZ043-044.
         SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR LOZ042.
         SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LOZ045.

&&

$$

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




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