Area Forecast Discussion
Issued by NWS Buffalo, NY

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119
FXUS61 KBUF 110108
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
808 PM EST WED FEB 10 2016

.SYNOPSIS...
LAKE EFFECT SNOWS WILL CONTINUE SOUTH AND EAST OF THE GREAT LAKES
TONIGHT INTO THURSDAY WHILE A SURFACE TROUGH SLOWLY DROPS SOUTH FROM
LAKE ONTARIO. BEHIND THIS TROUGH A PROGRESSIVELY COLDER ARCTIC
AIRMASS WILL OVERSPREAD THE REGION INTO THE WEEKEND. THE MOST FRIGID
CONDITIONS AND DANGEROUSLY COLD WIND CHILLS ARE EXPECTED FRIDAY
NIGHT THROUGH SATURDAY AND SATURDAY NIGHT ALONG WITH ANOTHER PERIOD
OF LAKE EFFECT SNOW EAST OF THE LAKES.

&&

.NEAR TERM /THROUGH THURSDAY/...
AN AMPLIFIED UPPER LEVEL TROUGH LIES ACROSS THE EASTERN STATES THIS
AFTERNOON WITH A SURFACE LOW SHIFTING INTO SOUTHERN QUEBEC. A WEAK
SURFACE TROUGH IS TRAILING THIS LOW ACROSS LAKE ONTARIO WHICH WILL
SLOWLY PRESS SOUTH OVERNIGHT. REGIONAL RADARS AT 3PM ARE SHOWING
LAKE EFFECT SNOWS SOUTH AND EAST OF THE GREAT LAKES AS COLDER AIR
CROSSES THE STILL OPEN WATERS. RADAR ESTIMATED SNOW RATES WITHIN
MULTIPLE NARROW BANDS EAST OF LAKE ERIE ARE RANGING FROM A HALF TO
AS HIGH AS ONE AND A HALF INCHES PER HOUR INCH WITH A PERSISTENT
MORE IMPRESSIVE SNOW BAND WITH 1 TO 2+ INCHES PER HOUR RATES HUGGING
THE LAKE ONTARIO SHORELINE ACROSS NIAGARA...ORLEANS AND MONROE
COUNTIES AND EXTENDING EAST BUT A BIT WEAKER ACROSS WAYNE...NORTHERN
CAYUGA AND SOUTHERN OSWEGO COUNTIES. THE MORE IMPRESSIVE SNOW RATES
ACROSS THE IMMEDIATE LAKE ONTARIO SHORELINE ARE DO TO SURFACE
CONVERGENCE AHEAD OF THE APPROACHING SURFACE TROUGH AND AN UPSTREAM
MOISTURE CONNECTION TO GEORGIAN BAY. LAKE EFFECT WARNINGS REMAIN IN
EFFECT ALONG THE SOUTHERN LAKE ONTARIO LAKE SHORE AND EAST OF LAKE
ERIE SOUTH OF BUFFALO.

TONIGHT AND THURSDAY...EXPECT THE SURFACE TROUGH TO SLOWLY PRESS
SOUTH OF LAKE ONTARIO LIKELY NOT FULLY PASSING SOUTH OF WESTERN NEW
YORK UNTIL THURSDAY. LAKE EFFECT SNOWS SHOULD HOLD THEIR CURRENT
POSITION THROUGH MUCH OF TONIGHT AHEAD OF THE TROUGH WITH A SLIGHT
SHIFT TO THE SOUTH INTO THURSDAY. BUFKIT PROFILES SHOW LAKE INDUCED
INSTABILITY WILL INCREASE OVERNIGHT AS COLDER AIR ARRIVES PEAKING
NEAR 12FT AROUND 12Z THURSDAY. THIS ALONG WITH A FAVORABLE CROSSHAIR
SIGNATURE OF MOISTURE...LIFT AND SNOW GROWTH SHOULD CONTINUE TO
BRING STEADY ACCUMULATING SNOW WITHIN THE SNOW BANDS. 12Z MESOSCALE
MODELS INCLUDING THE SSEO AND HIGH RES NMM/ARW SHOW THE LAKE ERIE
BAND WILL MAKE A PUSH SOUTH TOWARD ERIE PA ON THURSDAY UNDER A MORE
NORTHERLY VEERING OF THE WINDS WHICH MAY BRING A FEW HOUR BREAK IN
THE LAKE EFFECT SNOW FOR MUCH OF THE WARNING AREA. FOR LAKE ONTARIO
THE BAND SHOULD TEND TO FOCUS MORE TOWARD THE SOUTHEAST SHORES OF
LAKE ONTARIO AS WINDS BECOME MORE NORTHWESTERLY BEHIND THE SURFACE
TROUGH. ADDITIONAL SNOWFALL ACCUMULATIONS TONIGHT AND THURSDAY
WITHIN MORE PERSISTENT LAKE SNOWS WILL TOTAL MORE THAN A FOOT WITH
STORM TOTAL MAXES OF NEAR TWO FEET CENTERED OVER NORTHEAST WAYNE
COUNTY AND SOUTHWEST CHAUTAUQUA COUNTY ON THE CHAUTAUQUA RIDGE.

OUTSIDE OF THE LAKE EFFECT...MOIST CYCLONIC FLOW WILL CONTINUE A
FORECAST FOR CHANCE TO LIKELY POPS WITH LIGHT SNOWFALL ACCUMULATIONS
OF AN INCH OR TWO. AS FOR TEMPERATURES...EXPECT THESE TO STEADILY
DROP THROUGH THIS EVENING BOTTOMING OUT IN THE 5-15 RANGE ACROSS
MUCH OF THE AREA OVERNIGHT. ON THURSDAY CONTINUED COLD ADVECTION
BEHIND THE SURFACE TROUGH WILL KEEP TEMPERATURES STRUGGLING TO BREAK
INTO THE TEENS WITH A STEADY NORTHWESTERLY BREEZE HOLDING WIND CHILLS
LARGELY BELOW ZERO.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AN UPPER LEVEL TROUGH AXIS WILL EXIT EAST INTO NEW ENGLAND THURSDAY
NIGHT THEN ANOTHER SHORTWAVE AND WEAK SURFACE LOW WILL APPROACH ON
FRIDAY. THIS WILL SHIFT WINDS FROM THE WNW THURSDAY EVENING TO THE
SW BY FRIDAY WHICH WILL LIFT LAKE EFFECT SNOW BANDS NORTHWARD.

OFF LAKE ERIE...LIMITED MOISTURE AND SHEAR FROM THE SHIFTING FLOW
SHOULD DISRUPT LAKE SNOWS THURSDAY EVENING...BUT BY FRIDAY MORNING
FORECAST WIND FIELDS SUGGEST A FAIRLY WELL ALIGNED SW/250 FLOW.
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 REFLECTS THESE TRENDS...BUT SUSPECT THAT THE CONSENSUS
PLACES THE BAND TOO FAR SOUTH AND INLAND. THIS IS BECAUSE THE WSW
925MB FLOW TENDS TO FUNNEL UP THE CHAUTAUQUA RIDGE WHICH WOULD FOCUS
THE HEAVIEST SNOWS ACROSS SOUTHERN ERIE AND FAR NORTHERN CHAUTAUQUA
COUNTY...OR THE SOUTH TOWNS TO SKI COUNTRY WITH 6 TO 10 INCHES A
POSSIBILITY IF THE BAND DEVELOPS AS EXPECTED. THE RGEM HAS THE BEST
HANDLE ON THIS. BY FRIDAY AFTERNOON THE APPROACHING SHORTWAVE SHOULD
INCREASE SHEAR AND RESULT IN A MORE DIFFUSE AREA OF LAKE EFFECT SNOW
WHICH WILL PRODUCE A LARGER AREA OF MODERATE SNOWS WHICH COULD BRING
A COUPLE INCHES. BASED ON THIS WILL ISSUE A LAKE EFFECT SNOW WATCH
FOR CHAUTAUQUA/CATTARAUGUS AND SOUTHERN ERIE COUNTIES. THE BAND MAY
SNEAK INTO THE NORTHERN ERIE ZONE EVEN THOUGH IT SHOULD STAY SOUTH
OF DOWNTOWN BUFFALO.

OFF LAKE ONTARIO...THE MOST TRICKY PART OF THE FORECAST IS THURSDAY
EVENING WHEN THERE IS A WELL ALIGNED AND FAIRLY STRONG WNW FLOW
FORECAST ACROSS THE LAKE. AS THIS FLOW DIMINISHES A BIT THERE IS A
POTENTIAL FOR THIS TO CONSOLIDATE INTO A NARROW BUT INTENSE BAND.
HOWEVER...THIS FAVORABLE ENVIRONMENT WILL ONLY LAST FOR 3-6
HOURS...THEN SHEAR WILL INCREASE AS THE WINDS SHIFT TO THE SOUTHWEST
AND LIFT THE BAND QUICKLY NORTHWARD. MOST MESOSCALE GUIDANCE ONLY
SHOWS A BRIEF AND FAIRLY TRANSIENT BAND. THIS LOWERS FORECAST
CONFIDENCE A BIT...BUT WITH THE LONG FETCH AND FORECAST WIND FIELDS
THERE STILL APPEARS TO BE A FEW HOURS OF INTENSE SNOW SOUTHEAST OF
THE LAKE FROM WAYNE TO OSWEGO COUNTY. AFTER THIS...A WELL ALIGNED
SOUTHWESTERLY FLOW IS FORECAST TO DEVELOP SIMILAR TO LAKE ERIE. THIS
WILL NOT ONLY TAP INTO MOISTURE FROM THE APPROACHING SHORTWAVE...BUT
ALSO MOISTURE FROM WHATEVER FORMS ON LAKE ERIE. THIS PROVIDES AMPLE
CONFIDENCE TO ISSUE A LAKE EFFECT SNOW WATCH FOR JEFFERSON COUNTY
WITH A POTENTIAL OF SIGNIFICANT SNOW ON FRIDAY FOR WATERTOWN AND
VICINITY. CONSENSUS 850MB TEMPERATURES ARE STILL AROUND -16C AND THE
EQUILIBRIUM LEVEL IS FORECAST TO DEEPEN TO NEARLY 15K FT AND A
FAVORABLY DENDRITIC SNOW GROWTH ZONE. GIVEN THESE INGREDIENTS IN
PLACE...WOULD NOT BE SURPRISED IF SOME LOCATIONS TOPPED A FOOT OF
SNOW. LAKE EFFECT SNOW MAY CLIP NORTHERN LEWIS COUNTY...BUT FOR NOW
EXPECT ADVISORY TYPE AMOUNTS.

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 NNW. 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 /01Z THURSDAY THROUGH MONDAY/...
COLD AND MOIST FLOW WITHIN AN UPPER LEVEL TROUGH ACROSS THE GREAT
LAKES IS CONTRIBUTING TO ENHANCED LAKE EFFECT SNOWS SOUTH AND EAST
OF THE LAKES. OVERALL EXPECT IFR OR LOWER CIGS/VIS IN LAKE EFFECT
SNOWS WITH MVFR CIGS OUTSIDE OF THE LAKE SNOWS.

TONIGHT INTO THURSDAY...EXPECT CONTINUED IFR/LIFR IN AREAS OF
HEAVIER LAKE EFFECT SNOW EAST AND SOUTH OF THE LAKES...WITH MVFR/IFR
CIGS ELSEWHERE. WINDS WILL SHIFT MORE NORTHWESTERLY LATE TONIGHT
INTO THURSDAY BEHIND A SURFACE TROUGH.

OUTLOOK...
THURSDAY NIGHT...MVFR/IFR IN SHIFTING LAKE EFFECT SNOW
SHOWERS...EAST AND SOUTH OF THE LAKES.
FRIDAY...IFR/MVFR WITH SNOW SHOWERS LIKELY...AND AREAS OF HEAVIER
LAKE EFFECT SNOW EAST OF THE LAKES.
SATURDAY...IFR/MVFR IN LAKE EFFECT SNOW SHOWERS SOUTH OF THE
LAKES... WITH MVFR/VFR ACROSS THE NORTH COUNTRY.
SUNDAY...CHANCE OF IFR/MVFR IN WEAKENING LAKE EFFECT SNOW SHOWERS
SOUTH OF THE LAKES.
MONDAY...MAINLY VFR. 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
ALONG WITH THE POTENTIAL FOR MODERATE FREEZING SPRAY.

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

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WATCH FROM LATE THURSDAY NIGHT THROUGH LATE
     FRIDAY NIGHT FOR NYZ007.
     LAKE EFFECT SNOW WARNING UNTIL 4 AM EST FRIDAY FOR NYZ004>006.
     LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THURSDAY FOR
     NYZ001>003-019-020-085.
     LAKE EFFECT SNOW WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
     EVENING FOR NYZ012-019-020-085.
     LAKE EFFECT SNOW WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
     EVENING FOR NYZ010-011.
     LAKE EFFECT SNOW ADVISORY UNTIL 4 AM EST THURSDAY FOR NYZ013.
     LAKE EFFECT SNOW WARNING UNTIL 4 AM EST THURSDAY FOR NYZ012.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR
         LOZ042>045.

&&

$$

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



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