Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 111152
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
652 AM EST THU FEB 11 2016

.SYNOPSIS...
A GENERAL WEST-NORTHWESTERLY FLOW OF COLD AIR WILL CONTINUE
ACROSS THE LOWER GREAT LAKES TODAY AND INTO THIS EVENING...WHICH
WILL MAINTAIN AREAS OF LAKE EFFECT SNOW SOUTHEAST OF THE LAKES.
WINDS WILL THEN TURN MORE SOUTHWESTERLY LATER TONIGHT AND FRIDAY
OUT IN ADVANCE OF AN APPROACHING ARCTIC COLD FRONT...RESULTING IN
THE LAKE SNOWS LIFTING NORTHWARD TO THE BUFFALO AND WATERTOWN
AREAS. THE ARCTIC FRONT ITSELF WILL THEN CROSS THE REGION LATE
FRIDAY AFTERNOON AND FRIDAY EVENING WHILE BRINGING A BURST OF SNOW
TO MOST AREAS... WITH DOWNRIGHT FRIGID CONDITIONS AND DANGEROUSLY
COLD WIND CHILLS THEN FOLLOWING IN ITS WAKE FOR FRIDAY NIGHT
THROUGH SATURDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1150Z...THE LAKE SNOWS HAVE SAFELY EXITED TO THE SOUTH OF
SOUTHERN ERIE COUNTY...SO HAVE DROPPED THE LES WARNING THERE.

A GENERAL WEST-NORTHWESTERLY FLOW OF COLD AIR WILL CONTINUE TO
MAINTAIN LAKE SNOWS EAST-SOUTHEAST OF THE LAKES TODAY...WITH THESE
BECOMING INCREASINGLY MULTIBANDED IN NATURE DUE TO THE RESULTANT
SHORTER FETCH ACROSS THE LAKES. EXPECT THE MOST SIGNIFICANT
REMAINING SNOWS TO COME THIS MORNING...WITH THE ACTIVITY THEN
GRADUALLY SHRINKING UP SOME AND WEAKENING FROM WEST TO EAST THIS
AFTERNOON WITH DIMINISHING UPSTREAM CONNECTIONS...THE INTRUSION OF
DRIER AIR ALOFT...AND EVENTUALLY A LOWERING CAPPING INVERSION...WITH
THE LOWERING INVERSION MOST COMING INTO PLAY ACROSS LAKE ERIE AND
WESTERN LAKE ONTARIO. IN TERMS OF SNOWFALL AMOUNTS...THE HEAVIEST
ACCUMULATIONS ARE EXPECTED ACROSS CHAUTAUQUA AND CATTARAUGUS COUNTIES
DOWNWIND OF LAKE ERIE AND ACROSS THE WAYNE-SOUTHERN OSWEGO COUNTY
CORRIDOR SOUTHEAST OF LAKE ONTARIO...WHERE ADDITIONAL ACCUMULATIONS
OF 5 TO 8 INCHES WILL BE LIKELY WITHIN THE HEAVIEST AND MOST PERSISTENT
SNOW BANDS TODAY. MEANWHILE...SOMEWHAT LESSER ADDITIONAL AMOUNTS OF
3 TO 6 INCHES WILL BE LIKELY ACROSS THE NIAGARA-MONROE COUNTY CORRIDOR
TODAY...WITH THE HEAVIEST ACCUMULATIONS IN THIS REGION MOST LIKELY
ACROSS NORTHERN AND EASTERN PORTIONS OF MONROE COUNTY. GIVEN THESE...
THE EXISTING LAKE EFFECT SNOW WARNINGS FOR THE ABOVE REGIONS WILL
REMAIN IN EFFECT.

OUTSIDE OF THE MAIN LAKE EFFECT SNOW AREAS...THE REMAINDER OF THE
REGION WILL JUST EXPERIENCE MUCH LIGHTER AND MUCH MORE SCATTERED
TRANSIENT LAKE AND OROGRAPHICALLY-DRIVEN LIGHT SNOW SHOWERS...WITH
ONLY MINOR ADDITIONAL ACCUMULATIONS EXPECTED. OTHERWISE IT WILL
BE COLD AND ON THE BRISK SIDE AGAIN...WITH DAYTIME HIGHS ONLY
RANGING FROM AROUND 10 ABOVE ACROSS THE HIGHEST TERRAIN TO THE MID
TEENS ELSEWHERE.

TONIGHT...A CONTINUED WEST-NORTHWESTERLY FLOW WILL CONTINUE TO
MAINTAIN WEAKER LAKE SNOWS SOUTHEAST OF THE LAKES FOR A GOOD
PORTION OF THIS EVENING...WITH THIS ACTIVITY BEING HELD MORE
IN CHECK BY THE AFOREMENTIONED LOWERING CAPPING INVERSION...
WHICH WILL RUN BETWEEN 3 AND 5 KFT OFF LAKE ERIE...AND WILL DROP
TO BETWEEN 4 AND 5 KFT OFF LAKE ONTARIO. AFTER THAT TIME...GRADUAL
BACKING OF THE LOW LEVEL FLOW TO WESTERLY AND THEN WEST-SOUTHWESTERLY
IN ADVANCE OF AN APPROACHING ARCTIC FRONT WILL RESULT IN THE LAKE
BANDS SLOWLY MIGRATING NORTHWARD THROUGH THE BALANCE OF THE NIGHT...
WITH THE LAKE ERIE ACTIVITY REACHING THE BUFFALO SOUTHTOWNS...AND
THE LAKE ONTARIO LAKE SNOWS REACHING THE TUG HILL REGION BY
DAYBREAK. WHILE A CONTINUED LOWER CAP AND INCREASING AMOUNTS
OF DIRECTIONAL SHEAR BELOW IT SHOULD KEEP THE MIGRATING LAKE
SNOWS FROM BECOMING TERRIBLY ORGANIZED...THE GRADUALLY INCREASING
FETCH ACROSS BOTH LAKES SHOULD ALLOW FOR AT LEAST SOME INCREASE
IN STRENGTH LATE...ENOUGH FOR THE BANDS TO PRODUCE AN ADDITIONAL
INCH OR TWO OF ACCUMULATION DURING THEIR NORTHWARD MIGRATION.
AT THIS POINT IT APPEARS THAT THE MORE SIGNIFICANT ACCUMULATIONS
FROM THESE WILL HOLD OFF UNTIL DURING THE DAY ON FRIDAY...WHEN
DEEPENING MOISTURE AND A RISING CAP OUT IN ADVANCE OF THE
APPROACHING ARCTIC BOUNDARY SHOULD ALLOW FOR A NOTEWORTHY UPTICK
IN BAND ORGANIZATION...MORE ON WHICH IS DISCUSSED IN THE SHORT
TERM SECTION BELOW.

OUTSIDE OF THE LAKE SNOWS...EXPECT A QUIET AND LARGELY DRY NIGHT
TONIGHT...WITH LOWS RANGING FROM AROUND ZERO ACROSS THE NORTH
COUNTRY TO THE 5 TO 10 ABOVE RANGE ELSEWHERE. GIVEN A DEVELOPING
WARM AIR ADVECTION REGIME...THESE WILL LIKELY OCCUR AROUND
MIDNIGHT...BEFORE GIVING WAY TO SLOWLY RISING TEMPERATURES
OVERNIGHT.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
LAKE SNOWS WILL REORGANIZE AND INTENSIFY FRIDAY AS THE FLOW BACKS
TO SOUTHWEST IN RESPONSE TO A WEAK LOW DROPPING SOUTH FROM CANADA
AND AHEAD OF THE ADVANCING ARCTIC BOUNDARY.

OFF LAKE ERIE...FORECAST SOUNDINGS CONTINUE TO SHOW A FAIRLY WELL
ALIGNED SOUTHWEST FLOW LOW LEVEL FLOW DEVELOPING EARLY FRIDAY.
INITIALLY MOISTURE WILL BE LIMITED...BUT WITH THE APPROACH OF THE
LOW AND LONG FETCH DOWN THE LAKE...EXPECT A FAIRLY CONSOLIDATED AND
INTENSE LAKE EFFECT BAND TO DEVELOP. CONSENSUS HIGH RESOLUTION
GUIDANCE CONTINUES TO REFLECT THESE TRENDS. THE RGEM ALONG WITH THE
NAM/GFS ALL SUGGEST A STRONG CONVERGENCE SHOULD CONTINUE TO LIFT
NORTHWARD INTO BUFFALO METRO AREA DURING THE DAY FRIDAY. FAVORABLE
LAKE PARAMETERS WILL EXIST WITH PLENTY OF OVER-LAKE INSTABILITY AS
INVERSION HEIGHTS APPROACH 10K FEET WITHIN A WELL ALIGNED SOUTHWEST
FLOW...WITH THE BAND POSSIBLY EXTENDING INLAND ACROSS WYOMING AND
GENESEE COUNTIES...AND EVEN PERHAPS AS FAR NORTH AS NIAGARA AND
ORLEANS COUNTIES IF THE FLOW CAN BACK ENOUGH. FOR NOW WILL MAINTAIN
THE LAKE EFFECT SNOW DUE TO UNCERTAINTIES IN THE EXACT PLACEMENT OF
THE HEAVIEST BAND.

OFF LAKE ONTARIO...A WELL ALIGNED SOUTHWESTERLY FLOW IS FORECAST TO
DEVELOP FRIDAY SIMILAR TO LAKE ERIE. THIS WILL NOT ONLY TAP INTO
MOISTURE FROM AN APPROACHING SHORTWAVE...BUT ALSO MOISTURE FROM
WHATEVER FORMS OFF LAKE ERIE. THIS WILL BRING THE POTENTIAL FOR
SIGNIFICANT SNOWS ON FRIDAY INTO FRIDAY NIGHT FOR WATERTOWN AND
VICINITY...WITH THE BAND POSSIBLY EXTENDING INLAND ACROSS NORTHERN
LEWIS COUNTY. 850 MB TEMPERATURES AROUND -16C AND INVERSION HEIGHTS
FORECAST TO RISE TO NEARLY 15K FT AND A FAVORABLY DENDRITIC SNOW
GROWTH ZONE SHOULD PROVIDE FAVORABLE PARAMETERS FOR SIGNIFICANT
SNOWS. WILL MAINTAIN THE LAKE EFFECT SNOW WATCH FOR JEFFERSON COUNTY
AND ADD LEWIS COUNTY WITH THE POTENTIAL FOR SIGNIFICANT LAKE SNOWS
REACHING THE NORTHERN PART OF THE COUNTY.

ON FRIDAY EVENING...A POWERFUL ARCTIC FRONT WILL SURGE SOUTH ACROSS
THE REGION. THIS ARCTIC FRONT WILL LIKELY CAPTURE AND MERGE WITH THE
LAKE EFFECT SNOW BAND OFF LAKE ONTARIO...WITH A VERY HEAVY SNOW
SQUALL PASSING SOUTH ACROSS THE EASTERN LAKE ONTARIO REGION. THIS
WILL LIKELY PRODUCE AN INCH OR TWO OF SNOW IN MANY AREAS...WITH
LOCALLY HIGHER AMOUNTS SOUTHEAST OF THE LAKES WHERE THE LAKE
CONTRIBUTION MAXIMIZES. BEHIND THE ARCTIC FRONT...MULTIPLE STREAMERS
OF LAKE EFFECT SNOW SHOWERS WILL DEVELOP SOUTH OF THE LAKES LATE
FRIDAY NIGHT AS FLOW BECOMES NORTHWEST AND EVENTUALLY NORTH
NORTHWEST. THE FRONT WILL ALSO USHER IN BITTERLY COLD TEMPERATURES
WHICH WILL BE BELOW ZERO IN MOST AREAS BY DAYBREAK SATURDAY.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A FRIGID ARCTIC AIRMASS WILL TAKE HOLD OF THE EASTERN GREAT LAKES
AND NEW ENGLAND THIS WEEKEND. A CONSENSUS OF 12Z GUIDANCE DROPS
850MB TEMPERATURES TO AROUND -30C AT BUFFALO DURING THE DAY AT
BUFFALO...WITH -33C ACROSS THE EASTERN LAKE ONTARIO REGION. THE
COLDEST TEMPERATURE EVER RECORDED AT 850MB ON A KBUF SOUNDING IN THE
MONTH OF FEBRUARY IS -28C...AND THE COLDEST EVER RECORDED FOR ANY
MONTH IS -32C.

THIS WILL RESULT IN BITTERLY COLD TEMPERATURES DURING THE DAY
SATURDAY WITH DAYTIME TEMPERATURES STRUGGLING TO RISE ABOVE ZERO.
DAYTIME HIGHS WILL ALMOST CERTAINLY BE BELOW ZERO IN THE EASTERN
LAKE ONTARIO REGION. PERSISTENT WINDS OF 10 TO 15 MPH ON SATURDAY
NIGHT WILL LIMIT RADIATIONAL COOLING...BUT EVEN SO IT WILL BE VERY
COLD WITH BELOW ZERO LOWS REGION-WIDE. LOWS OF -20F OR COLDER ARE
POSSIBLE ACROSS THE NORTH COUNTRY WITH NO MODERATING LAKE INFLUENCE.
THE COMBINATION OF MODERATE WINDS AND FRIGID TEMPERATURES WILL
PRODUCE DANGEROUSLY COLD WIND CHILLS LATE FRIDAY NIGHT THROUGH EARLY
SUNDAY MORNING.

THE FRIGID NORTH FLOW OVER THE LAKES WILL PRODUCE WIDESPREAD LAKE
EFFECT SNOW SHOWERS ACROSS WESTERN AND CENTRAL NY. DESPITE THE
EXTREME INSTABILITY...AIRMASSES THIS COLD ARE ALSO VERY DRY AND
TEMPERATURES BECOME TOO COLD FOR DENDRITES. THIS WILL FORCE
SNOWFLAKES TO BE VERY SMALL AND LIMIT ACCUMULATIONS...ALTHOUGH
SEVERAL INCHES ARE LIKELY SOUTH OF BOTH LAKES. THE LAKE EFFECT SNOW
WILL DIMINISH IN COVERAGE AND INTENSITY SUNDAY. 12Z GUIDANCE IS A
BIT FASTER MOVING THE SURFACE RIDGE ACROSS THE REGION...WITH LAKE
EFFECT SNOW LIKELY TO TAPER OFF BY SUNDAY NIGHT.

AFTER THIS THERE IS GENERAL MODEL AGREEMENT THAT TEMPERATURES WILL
WARM BACK TO NEAR NORMAL EARLY NEXT WEEK. HOWEVER...THE 12Z ECMWF
IS SIGNIFICANTLY DIFFERENT FROM THE GFS/GGEM. THE ECMWF HAS
CONSISTENTLY DEVELOPED A STRONG WAVE OF LOW PRESSURE WITH
SIGNIFICANT QPF ACROSS OUR REGION WHICH WOULD FALL AS RAIN OR
SNOW. THE GGEM/GFS HAVE THIS SYSTEM BUT KEEP IT WELL TO OUR
EAST...AND INSTEAD ARE A BIT COLDER WITH A CHANCE FOR LIGHT SNOW
SHOWERS. THE FORECAST WILL REFLECT A CONSENSUS BETWEEN THIS
GUIDANCE...WITH NEAR NORMAL TEMPERATURES AND CHANCE POPS.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
LAKE EFFECT SNOWS AND ATTENDANT IFR/LIFR WILL BE FOUND EAST-
SOUTHEAST OF THE LAKES TODAY AND INTO THIS EVENING...WITH MVFR/VFR
CONDITIONS AND MUCH MORE SCATTERED SNOW SHOWERS PREVAILING
ELSEWHERE. EXPECT THE MOST SIGNIFICANT LAKE SNOWS OF THE DAY TO
COME THIS MORNING...WITH THE ACTIVITY THEN GRADUALLY WEAKENING
FROM WEST TO EAST THIS AFTERNOON AND EVENING IN CONJUNCTION WITH
DIMINISHING UPSTREAM CONNECTIONS...THE INTRUSION OF DRIER AIR
ALOFT...AND A LOWERING CAPPING INVERSION.

FROM THE LATE EVENING HOURS ON THROUGH THE REMAINDER OF
TONIGHT... GRADUAL BACKING OF THE LOW LEVEL FLOW TO WESTERLY AND
THEN WEST- SOUTHWESTERLY IN ADVANCE OF AN APPROACHING ARCTIC FRONT
WILL RESULT IN WEAKER LAKE SNOWS SLOWLY MIGRATING NORTHWARD...WITH
THE LAKE ERIE ACTIVITY REACHING THE BUFFALO SOUTHTOWNS...AND THE
LAKE ONTARIO LAKE SNOWS REACHING THE TUG HILL REGION BY 12Z
FRIDAY. EXPECT IFR/MVFR TO PREVAIL WITHIN THE MIGRATING LAKE
SNOWS...WITH GENERAL VFR CONDITIONS THE RULE ELSEWHERE.

OUTLOOK...
FRIDAY...IFR/MVFR WITH SNOW SHOWERS LIKELY...AND AREAS OF
HEAVIER LAKE EFFECT SNOW EAST/NORTHEAST OF THE LAKES.
SATURDAY...IFR/MVFR IN LAKE EFFECT SNOW SHOWERS SOUTH OF THE LAKES...
WITH MVFR/VFR ACROSS THE NORTH COUNTRY.
SUNDAY...A CHANCE OF IFR/MVFR IN WEAKENING LAKE EFFECT SNOW SHOWERS
SOUTH OF THE LAKES...OTHERWISE MVFR/VFR.
MONDAY...MAINLY VFR WITH A CHANCE OF SNOW SHOWERS.

&&

.MARINE...
A BRISK FLOW OF PROGRESSIVELY COLDER ARCTIC AIR WILL CONTINUE TO
OVERSPREAD THE REGION THROUGH THE WEEKEND...RESULTING IN A PROLONGED
PERIOD OF ADVISORY-WORTHY WINDS AND WAVES ACROSS THE LOWER LAKES.

IN ADDITION TO THE ABOVE...THE PASSAGE OF AN ARCTIC COLD FRONT LATER
FRIDAY AFTERNOON AND FRIDAY EVENING WILL ALSO USHER IN A TRULY FRIGID
AIRMASS FOR LATER FRIDAY NIGHT AND THE UPCOMING WEEKEND...WHICH IN
CONJUNCTION WITH THE AFOREMENTIONED WINDS WILL RESULT IN A GREATLY
HEIGHTENED POTENTIAL FOR HEAVY FREEZING SPRAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH LATE FRIDAY
     NIGHT FOR NYZ007-008.
     LAKE EFFECT SNOW WARNING UNTIL 4 AM EST FRIDAY FOR NYZ004>006.
     LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
     NYZ001>003-019-020.
     LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH FRIDAY
     EVENING FOR NYZ012-019-020-085.
     LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH FRIDAY
     EVENING FOR NYZ010-011.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR
         LOZ042>045.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...TMA
LONG TERM...APFFEL
AVIATION...JJR
MARINE...JJR


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