Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 292351
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
751 PM EDT SUN MAR 29 2015

.SYNOPSIS...
LOW PRESSURE WILL PASS JUST NORTH OF THE GREAT LAKES TONIGHT AND
MONDAY BRINGING GUSTY WINDS AND A LIGHT MIX OF WET SNOW AND RAIN.
THERE WILL BE SOME MINOR SNOW ACCUMULATIONS ACROSS HIGHER TERRAIN.
ANOTHER SYSTEM MAY BRING WET SNOW AND RAIN TO WESTERN NEW YORK TUESDAY
BEFORE HIGH PRESSURE BRINGS A RETURN TO DRY WEATHER FOR WEDNESDAY.
TEMPERATURES WILL REMAIN BELOW NORMAL EARLY IN THE WEEK BEFORE A
STRONG PUSH OF WARMING ARRIVES ON THURSDAY.

&&

.NEAR TERM /THROUGH MONDAY/...
THIS EVENING AN AREA OF LOW PRESSURE IS FOUND NEAR JAMES BAY WITH A
COLD FRONT EXTENDING SOUTHWARD ACROSS THE CENTRAL GREAT LAKES AND
DOWN INTO THE DEEP SOUTHERN PLAINS. SHOWERS AND SNOW SHOWERS ALONG
THIS FRONTAL BOUNDARY ARE NOW FROM THE PENINSULA OF
ONTARIO...WESTERN LAKE ERIE AND THE STATE OF OHIO. THE 00Z
BUFFALO SOUNDING SHOWS A WEALTH OF DRY AIR FROM ABOUT 650 HPA AND
BELOW...AND EXPECT SOME DIMINISHING TO THE SHOWERS TO THE WEST AS
IT ENCROACHES UPON THIS DRY AIRMASS.

THINGS GET A BIT MORE COMPLICATED TONIGHT WITH THE APPROACH AND
PASSAGE OF A FRONTAL BOUNDARY AND UPPER LEVEL TROUGH. AHEAD OF THIS
BOUNDARY A 50-60KT LLJ WILL ENTER THE REGION LATE THIS EVENING AND
MOVE EASTWARD OVERNIGHT.

P-TYPE WILL BE A CHALLENGE FOR THIS EVENT WITH MARGINAL BOUNDARY
LAYER TEMPERATURES AND A THE GFS/RGEM SLIGHTLY WARMER THAN THE
NAM/SREF. WILL LIKELY HAVE A MIX PRECIPITATION TO START...WITH FALLING
PRECIPITATION ASSOCIATED WITH THE LIFT AHEAD OF THE LLJ RATHER
MINIMAL. LIKE MANY SPRING TIME MIX PRECIPITATION EVENTS...HIGHER
ELEVATIONS WILL FAVOR THE GREATEST CHANCES FOR SNOW WITH THIS FIRST
WAVE OF PRECIPITATION. EXPECT THIS INITIAL ROUND OF PRECIPITATION TO
DIMINISH ACROSS THE GENESEE VALLEY...AND PERHAPS THIS REGION MAY
REMAIN DRY UNTIL WELL LATE TONIGHT.

ANOTHER ROUND OF PRECIPITATION WILL FOLLOW QUICKLY ON THE FIRST WAVE
AS THE FRONT AND SHORTWAVE NEAR. THIS PRECIPITATION IS LIKELY TO
ARRIVE AFTER MIDNIGHT...AND EXIT THE EASTERN LAKE ONTARIO REGION
JUST AFTER DAYBREAK. THIS SHOULD BRING ANOTHER ROUND OF
PRECIPITATION TO THE REGION. BOUNDARY LAYER TEMPERATURES SHOULD
AGAIN BE MARGINAL BEHIND THE INITIAL WAVE...BUT DOWNSLOPE WARMING
NORTH OF I-90 FROM BUF-ROC MAY TIP THE SCALE IN FAVOR OF RAIN.
EXPECT MOSTLY SNOW ACROSS HIGHER TERRAIN...WHERE SOME UPSLOPE
ENHANCEMENT IS LIKELY AS WINDS SHIFT FROM SSW TO WSW. IN GENERAL
SNOW ACCUMULATIONS TONIGHT SHOULD BE LIGHT...WITH LESS THAN AN INCH
NEAR THE LAKES...BUT AN INCH OR TWO ACROSS WESTERN PORTIONS OF THE
SOUTHERN TIER AND BOSTON HILLS. THE TUG HILL REGION...ESPECIALLY THE
SOUTH FACING PORTION OF THE TUG HILL MAY PICK UP A WET 2 TO 4
INCHES OF SNOW LATE TONIGHT AND THROUGH THE MORNING HOURS MONDAY.

WINDS WILL ALSO PICK UP TONIGHT...BOTH WITH THE LLJ AND FRONTAL
BOUNDARY. ALTHOUGH THE LLJ WILL BE QUITE STRONG...ITS CORE IS
BETWEEN 925-850MB WHICH MAY STRUGGLE TO MIX TO THE SURFACE. EXPECT
LIMITED DOWNSLOPE GUSTS THIS EVENING WHEN THE FLOW IS
SOUTHERLY...BUT THESE GUSTS SHOULD DIMINISH WITH THE CORE OF THE
LLJ SINCE WINDS ALOFT WILL SHIFT TO THE SSW AND BECOME LESS
PERPENDICULAR TO THE CHAUTAUQUA RIDGE. WINDS WILL BE GUSTY AGAIN
JUST BEHIND THE FRONT DUE TO TYPICAL FUNNELING DOWN THE
LAKES...HOWEVER BUFKIT SHOWS DIMINISHING WINDS ALOFT BEHIND THE
FRONT. FOR THESE REASONS...HAVE HELD OFF ON ANY HEADLINES...BUT DO
EXPECT PEAK GUSTS IN THE 40-45MPH RANGE WHICH IS JUST BELOW WIND
ADVISORY CRITERIA.

EXPECT A LULL IN THE ACTION BEHIND THE FRONT ON MONDAY MORNING. SNOW
SHOWERS MAY LINGER A BIT LONGER EAST OF LAKE ONTARIO...WITH FLURRIES
OR DRIZZLE ELSEWHERE. AFTER THIS...NAM/RGEM/GFS GUIDANCE ALL SHOW A
SHARP VORT MAX DIVING ACROSS WESTERN NEW YORK WITH SOME RESPONSE IN
THE QPF FIELD. THIS SHOULD SPARK ANOTHER ROUND OF
SHOWERS...ESPECIALLY ACROSS THE BOSTON HILLS AND WESTERN PORTIONS OF
THE SOUTHERN TIER WHERE UPSLOPING WILL ENHANCE LIFT.

WITH SLIGHT COLD AIR ADVECTION AND UNDER THE BASE OF THE UPPER LEVEL
TROUGH MUCH OF THE PRECIPITATION TYPE MONDAY WILL BE MAJORLY SNOW...EVEN
WITH SURFACE TEMPERATURES IN THE MID 30S. AREAS THAT COULD RECEIVE
RAIN SHOWERS MONDAY WILL BE THE LOWER ELEVATIONS NEAR THE LAKE
SHORES...AND THE GENESEE VALLEY. THIS COULD BRING ANOTHER SLUSHY
INCH OR TWO TO HIGHER ELEVATIONS...WITH LITTLE ACCUMULATION
ELSEWHERE WHERE ABOVE FREEZING TEMPERATURES SHOULD TRIM
ACCUMULATION. TEMPERATURES ON MONDAY SHOULD BE MAINLY IN THE 30S.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
THE UPPER TROUGH AND SURFACE TROUGH WILL MOVE OFF TO THE GULF OF
SAINT LAWRENCE WITH A WEAK RIDGE ACROSS THE REGION. LOW TEMPERATURES
MONDAY NIGHT INTO TUESDAY MORNING WILL MAINLY BE IN THE UPPER 20S.

A CLIPPER SHORTWAVE MOVE RAPIDLY FROM THE UPPER GREAT LAKES INTO
PENNSYLVANIA ON TUESDAY. AS THE TRACK IS MORE TO THE SOUTH THAN
PREVIOUS MODEL RUNS...IT BECOMES MORE LIKELY THAT THE PRECIP
ASSOCIATED WITH THIS CLIPPER WILL FALL AS SNOW. EARLY MORNING SNOW
MAY GIVE WAY TO A RAIN/SNOW MIX LATER IN THE DAY AS THE SNOW
INTENSITY DIMINISHES AND DYNAMIC COOLING LESSENS. WILL GO WITH
LIKELY TO CATEGORICAL POPS ACROSS THE WESTERN SOUTHERN TIER AND A
GOOD PORTION OF WESTERN NY...LESSENING TO CHANCE OR SLIGHT CHANCE
ACROSS CENTRAL AND NORTHERN NY. HIGH TUESDAY WILL BE IN THE MIDDLE
30S...AND LOWS TUESDAY NIGHT WILL BE IN THE LOWER TO MID 20S.

HIGH PRESSURE BUILDS ACROSS THE REGION ON WEDNESDAY WITH CLEARING
SKIES AND LIGHTER WINDS. HIGHS WILL BE IN THE MID TO UPPER 30S. AS
HIGH PRESSURE MOVES EAST OF THE REGION ON WEDNESDAY NIGHT...THE WIND
BECOMES SOUTHERLY. TEMPS WILL DIP A BIT DURING THE EVENING ACROSS
THE WESTERN COUNTIES...BUT WILL RISE TO NEAR 40 BY DAYBREAK.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THURSDAY WILL BE THE WARM DAY OF THE WEEK AS HIGH PRESSURE TO THE
EAST AND DEEP LOW PRESSURE TO THE WEST BRING STRONG WARM ADVECTION
TO THE AREA...HIGH TEMPERATURES CLIMBING TO THE MIDDLE 50S FOR MID
LOCATIONS...NEAR 60 ACROSS THE WESTERN FINGER LAKES AND TO THE UPPER
40S EAST OF LAKE ONTARIO. A COLD FRONT APPROACHING THE REGION FOR
THE SECOND HALF OF THE DAY WILL BRING STRONGER WINDS AND INCREASING
CLOUD COVER. THE COLD FRONTAL PASSAGE THURSDAY NIGHT WILL BRING
MODIFIED CONTINENTAL AIR...NOT AS COLD WITH LOWS IN THE MID TO UPPER
30S.

A BROAD UPPER TROUGH ACROSS THE REGION WILL KEEP THE WEATHER
UNSETTLED FOR FRIDAY AND SATURDAY WITH RAIN AND SNOW DURING THE
DAYS...MAINLY SNOW SHOWERS DURING THE NIGHTS. ANOTHER CLIPPER MOVES
THROUGH ON SATURDAY NIGHT AND SUNDAY MORNING WITH SNOW SHOWERS...
THEN HIGH PRESSURE BUILDS ACROSS THE REGION DURING SUNDAY AFTERNOON.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT 00Z VFR FLIGHT CONDITIONS ARE FOUND ACROSS THE REGION TO START
THE TAF PERIOD. THESE CONDITIONS WILL DETERIORATE TO MVFR ACROSS ALL
TAF SITES OVERNIGHT...WITH IFR IN SNOW SHOWERS/MIXED PRECIPITATION
ACROSS THE FAR WESTERN NEW YORK TAF SITES...AND ALSO THE KART
AIRFIELD OF THE NORTH COUNTRY.

PRECIPITATION WILL LIKELY ARRIVE IN SEVERAL ROUNDS...WITH THE FIRST
ROUND ASSOCIATED WITH LIFT AHEAD OF A LLJ REACHING FAR WESTERN NEW
YORK...AND THE NORTH COUNTRY BETWEEN 03Z AND 06Z. THIS ACTIVITY IS
EXPECTED TO BE SCATTERED DUE TO THE WEALTH OF DRY AIR OVER THE
REGION PRESENTLY. A SECOND ROUND OF PRECIPITATION AHEAD OF THE COLD
FRONT WILL FOLLOW SEVERAL HOURS LATER...WITH IFR EXPECTED FOR A
PORTION OF THE REGION.

SHOWERS OF SNOW...AND POSSIBLY RAIN WILL BE PROBABLE THROUGH THE
REMAINDER OF THE TAF CYCLE...WITH IFR/MVFR FLIGHT CONDITIONS.

A LLJ OF REACHING NEAR 50 KNOTS AT 2K FEET WILL PASS ACROSS THE
REGION WITHIN THE FIRST 6 HOURS OF THE TAF CYCLE...BRINGING MARGINAL
LLWS TO TAF SITES. SOUTHERLY WINDS WILL SLOWLY VEER AROUND TO
WESTERLY THROUGH THE TAF CYCLE AND FOR THE MOST PART REMAIN 10 KNOTS
OR STRONGER.

OUTLOOK...
MONDAY AFTERNOON...IFR/MVFR IN SNOW SHOWERS.
MONDAY NIGHT...MAINLY VFR.
TUESDAY...MVFR/IFR. SNOW SHOWERS LIKELY.
WEDNESDAY...VFR.
THURSDAY AND FRIDAY...VFR/MVFR. A CHANCE OF RAIN SHOWERS.

&&

.MARINE...
A FRONT WILL APPROACH THE WATERS FROM THE WEST WITH AN INCREASING
SSW FLOW. WINDS WILL PICK UP THIS EVENING...HOWEVER THIS FLOW TENDS
NOT TO MIX WINDS ALOFT TOO WELL. THE STRONGEST WINDS SHOULD COME
JUST BEHIND THE FRONT WHEN A WINDS SHIFT TO THE WSW. WINDS MAY
APPROACH GALES BEHIND THE FRONT...BUT 12Z GUIDANCE HAS TRENDED DOWN
WITH FORECAST WINDS BEHIND THE FRONT. IT WILL BE CLOSE...BUT EXPECT
WINDS TO STAY JUST BELOW GALE OUTSIDE OF A FEW GUSTS. WINDS WILL
DIMINISH MONDAY NIGHT AND TUESDAY AS HIGH PRESSURE GRADUALLY BUILDS
IN FROM THE WEST.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT TUESDAY FOR LOZ042-043.

&&

$$

SYNOPSIS...APFFEL/THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...THOMAS
MARINE...APFFEL






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