Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 040846
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
446 AM EDT MON MAY 4 2015

.SYNOPSIS...
HIGH PRESSURE SLIDING OFF THE MID ATLANTIC COAST TODAY WILL
COMBINE WITH A LOW PRESSURE TRACKING ACROSS SOUTHERN CANADA TO
PRODUCE A WARM AND BREEZY DAY ACROSS THE AREA. A COLD FRONT WILL
CROSS THE AREA THIS EVENING THROUGH TUESDAY AND BRING SHOWERS AND
POSSIBLY A FEW THUNDERSTORMS. TEMPERATURES WILL ONLY COOL FOR ONE
DAY BEHIND THE COLD FRONT WITH PLENTY OF WARMTH RETURNING FOR THE
SECOND HALF OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
OUR ATTENTION IN THE NEAR TERM TURNS TO DANGEROUS FIRE WEATHER
CONDITIONS TODAY. WITH ANOTHER WARM AND DRY DAY ON TAP...THE
COMBINATION OF WINDY CONDITIONS THIS AFTERNOON AND LACK OF RAIN
RECENTLY WILL PROMOTE ANY FIRE STARTS TO GROW AND SPREAD QUICKLY.
THUS HAVE ISSUED A RED FLAG WARNING FOR ALL OF WESTERN AND NORTH
CENTRAL NEW YORK.

A SHORTWAVE TROUGH PASSING ACROSS SOUTHERN CANADA WILL INCREASE THE
SOUTHWESTERLY RETURN FLOW ACROSS WESTERN AND CENTRAL NEW YORK TODAY.
THE THERMAL RIDGE AXIS WILL SHIFT ACROSS THE FORECAST AREA AHEAD OF
THE APPROACHING COLD FRONT...AND WILL PUSH 850 MB TEMPERATURES TO 11
TO 12C. THE COMBINATION OF THE WARM AIRMASS AND DOWNSLOPE WINDS WILL
PUSH TEMPERATURES IN THE GENESEE VALLEY INTO THE LOW TO MID 80S.
ELSEWHERE...THE LACK OF DOWNSLOPING WILL KEEP TEMPERATURES IN THE
MID 70S TO AROUND 80. THE LAKE SHORES WILL REMAIN THE COOL SPOT WITH
HIGHS IN THE 60S...ESPECIALLY NORTHEAST OF THE LAKES...INTO BUFFALO
WATERFRONT AND THE WATERTOWN AREA. NOT ONLY WILL IT BE WARM...BUT IT
WILL BE ANOTHER DRY DAY...WITH STRONG MIXING AHEAD OF THE COLD
FRONT...DEW POINTS WILL STRUGGLE TO RISE QUICKLY DESPITE SOME
MOISTURE ADVECTION INTO THE AREA. THUS RH VALUES WILL BE LARGELY IN
THE 25 TO 30 PERCENT RANGE ACROSS THE FORECAST AREA.

THE INCREASING PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE SLIDING
OFF THE MID ATLANTIC COAST AND THE SURFACE LOW TRACKING ACROSS
SOUTHERN CANADA WILL ALLOW SOUTHWESTERLY WINDS TO INCREASE TODAY.
WINDS OF 30 TO 40 KNOTS AT 850 MB AND DEVELOPING STEEP-LOW LEVEL
LAPSE RATES WITH STRONG DAYTIME HEATING...WILL ALLOW FOR STRONGER
WINDS ALOFT TO MIX TO THE SURFACE. THE STRONGEST WINDS ARE FORECAST
ALONG THE NIAGARA FRONTIER AND INTO NORTH COUNTRY ALONG THE SAINT
LAWRENCE RIVER VALLEY. THE WINDS WILL NOT BE AS STRONG OVER LAKES
ERIE AND ONTARIO WITH THE STABILIZING EFFECTS OF THE COLD LAKES.
JUST INLAND FROM THE LAKE BREEZES OFF LAKES ERIE AND
ONTARIO...EXPECT THESE STRONGER WINDS TO MAKE IT TO THE SURFACE. IN
THIS REGION...SUSTAINED WINDS AROUND 20 MPH WITH GUSTS TO 35 MPH ARE
EXPECTED. ACROSS THE SOUTHERN TIER AND FINGER LAKES REGION...WINDS
WILL BE SLIGHTLY LIGHTER...WITH SUSTAINED WINDS 15 TO 20 MPH WITH
GUSTS TO AROUND 30 MPH...BUT STILL ENOUGH TO POSE A FIRE WEATHER
CONCERN.

THE COLD FRONT WILL ARRIVE THIS EVENING...SPREADING A LINE OF
SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. THE ARRIVAL OF
THIS COOLER AIRMASS AND THE CHANCE FOR A WETTING RAINFALL MONDAY
NIGHT WILL PUT AN END TO THE FIRE WEATHER CONCERNS. TEMPERATURES
WILL BE MAINLY IN THE LOW TO MID 50S OVERNIGHT...WITH THE WARMER
TEMPERATURES FOUND ACROSS THE SOUTHERN TIER WHERE THE FRONTAL
BOUNDARY WILL BECOME TEMPORARILY STALLED. WITH THE BOUNDARY STALLED
ACROSS SOUTHERN NY OVERNIGHT...THIS AREA WILL HAVE THE BETTER CHANCE
TO RECEIVE MORE QPF. THUS TOTAL QPF AMOUNTS WILL RANGE FROM AROUND A
TENTH OF AN INCH ACROSS THE NORTH COUNTRY AND SOUTH OF LAKE
ONTARIO...UP TO AROUND A QUARTER INCH ACROSS THE SOUTHERN TIER.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A SURFACE COLD FRONT WILL PUSH SOUTH OF THE AREA TUESDAY MORNING
THEN STALL ACROSS THE UPPER OHIO VALLEY AND PA AND ACT AS A CORRIDOR
FOR SEVERAL ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS THROUGH
WEDNESDAY. THE FIRST BATCH OF SHOWERS WILL BE EXITING THE SOUTHERN
TIER AND FINGER LAKES TUESDAY MORNING. BY TUESDAY AFTERNOON MARGINAL
INSTABILITY WILL DEVELOP WITH MODEST DAYTIME HEATING AND A FEW
BREAKS IN THE CLOUD COVER FROM OHIO INTO PA...POSSIBLY EXTENDING
INTO THE SOUTHERN TIER. BOTH THE GFS AND NAM SHOW ANOTHER
CONVECTIVELY AUGMENTED MID LEVEL SHORTWAVE AND LOW LEVEL JET SEGMENT
MOVING EAST ACROSS PA DURING THE AFTERNOON AND EVENING. SOME OF THE
LOW LEVEL CONVERGENCE AND LARGE SCALE ASCENT FROM THIS FEATURE MAY
CLIP THE SOUTHERN TIER AND PRODUCE SHOWERS AND A FEW WIDELY
SCATTERED WEAK THUNDERSTORMS. ANYTHING THAT DOES DEVELOP WILL END
TUESDAY NIGHT AS THE FRONTAL ZONE SAGS A LITTLE FARTHER SOUTH.

FOR THE REST OF THE AREA A BUBBLE OF SURFACE HIGH PRESSURE WILL
BUILD INTO THE GREAT LAKES AND SHOULD PROVIDE ENOUGH DRYING AND
SUBSIDENCE TO KEEP AREAS FROM THE NYS THRUWAY NORTHWARD DRY. PERIODS
OF MID LEVEL CLOUDS WILL CROSS THE AREA NORTH OF THE STALLED SURFACE
BOUNDARY...WITH MORE SUNSHINE ACROSS THE NORTH COUNTRY FARTHER
REMOVED FROM THE FRONTAL ZONE. TUESDAY WILL BE THE COOLEST DAY OF
THE WEEK...BUT STILL REMAIN WARMER THAN NORMAL. EXPECT HIGHS IN THE
UPPER 60S TO AROUND 70 IN MOST AREAS. NORTHERLY FLOW WILL KEEP THE
SOUTH SHORE OF LAKE ONTARIO AND THE LAKE ERIE SHORE FROM HAMBURG
SOUTHWESTWARD MUCH COOLER.

BY WEDNESDAY THE FRONTAL ZONE WASHES OUT TO OUR SOUTH AND
WEST...WITH A BUBBLE OF HIGH PRESSURE REMAINING IN PLACE ACROSS NEW
YORK AND PA. THIS WILL PROVIDE A GOOD DEAL OF SUNSHINE WITH NOTHING
MORE THAN SOME PATCHY MID LEVEL CLOUDS AND SCATTERED DIURNAL
CUMULUS. THE AIRMASS WILL BEGIN TO MODERATE...WITH HIGHS IN THE LOW
TO MID 70S ACROSS THE BULK OF THE AREA. THE SYNOPTIC SCALE FLOW WILL
BE WEAK...SO STRONG DIFFERENTIAL HEATING WILL ALLOW LOCAL LAKE
BREEZES TO FORM WHICH WILL KEEP ALL THE LAKESHORES COOLER.

DRY WEATHER CONTINUES WEDNESDAY NIGHT WITH HIGH PRESSURE SURFACE AND
ALOFT.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
A VERY WARM AND MID SUMMER-LIKE PATTERN WILL EVOLVE LATE THIS WEEK
AND INTO THE WEEKEND AS AN EXPANSIVE MID LEVEL RIDGE BUILDS INTO THE
OHIO VALLEY AND NORTHEAST. SEVERAL DAYS OF DEEP SOUTHWEST FLOW WILL
PUMP VERY WARM AIR INTO THE REGION...WITH EVEN A LITTLE HUMIDITY AS
WELL.

THE WARMING PROCESS WILL START THURSDAY WITH HIGHS IN THE MID TO
UPPER 70S INLAND FROM THE LAKES...AND AROUND 80 IN THE NORMALLY
WARMER GENESEE VALLEY. THE REAL WARMTH WILL ARRIVE FRIDAY AS 850MB
TEMPS SOAR TO AROUND +14C...SUPPORTING LOW TO MID 80S AT LOWER
ELEVATIONS AWAY FROM THE LAKES. EXPECT SIMILAR TEMPERATURES ON
SATURDAY BEFORE MORE CLOUD COVER AND BETTER RAIN CHANCES KNOCK A FEW
DEGREES OFF FOR SUNDAY.

THURSDAY AND FRIDAY WILL REMAIN DRY BENEATH THE EXPANSIVE MID LEVEL
RIDGE...WHICH WILL PROVIDE AN EFFECTIVE CAP AND PREVENT ANY DEEP
MOIST CONVECTION. THE SPURIOUS QPF ON THE GFS MODEL BY FRIDAY IS
LIKELY JUST GRIDSCALE CONVECTIVE FEEDBACK. BY SATURDAY AND SUNDAY
MOISTURE WILL DEEPEN AND SHORTWAVES WILL BEGIN TO MOVE OUT OF THE
MIDWEST AND TOWARDS OUR REGION...INCREASING THE CHANCE OF A FEW
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. WHILE BOTH DAYS WILL
FEATURE A CHANCE OF RAIN...EXPECT THE MAJORITY OF THE TIME TO BE
RAIN FREE.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR FLIGHT CONDITIONS WILL PREVAIL THE THROUGH MAJORITY OF THE
06Z TAF CYCLE. INCREASING SOUTHWEST WINDS THIS AFTERNOON COULD
PRODUCE SOME GUSTS UP TO 30 KNOTS ACROSS THE NIAGARA FRONTIER TO
ROCHESTER...IMPACTING KIAG/KBUF/KROC. CIGS WILL LIKELY
DETERIORATE TO LOW-END VFR / MVFR AFTER 00Z AS RAIN SHOWERS AND
THUNDERSTORMS MOVE ACROSS THE AREA FROM WEST TO EAST ALONG A COLD
FRONT.

OUTLOOK...
MONDAY NIGHT AND TUESDAY...VFR/MVFR. SHOWERS LIKELY WITH A CHANCE
OF THUNDERSTORMS.
WEDNESDAY THROUGH FRIDAY...VFR.

&&

.MARINE...
SOUTHWEST WINDS WILL INCREASE SOME ON MONDAY AHEAD OF A
COLD FRONT...ALTHOUGH THE COLD LAKE WATERS WILL STABILIZE THE
BOUNDARY LAYER OVER THE LAKES AND KEEP WINDS LIGHTER IN THE MARINE
ENVIRONMENT THAN OVER THE SURROUNDING LAND. THE EXCEPTION TO THIS
RULE WILL BE ALONG THE SAINT LAWRENCE RIVER VALLEY...WHERE STRONGER
WINDS WILL BE ABLE TO MIX TO THE SURFACE. WITH SOUTHWEST WINDS OF 15
TO 25 KNOTS EXPECTED THERE...HAVE ISSUED A SMALL CRAFT ADVISORY.
ELSEWHERE WINDS WILL FALL JUST SHY OF SMALL CRAFT CRITERIA. WINDS
WILL DIMINISH BEHIND THE FRONT...WITH QUIET CONDITIONS EXPECTED MID-
WEEK AS HIGH PRESSURE NOSES TOWARD THE WATERS.

&&

.FIRE WEATHER...
A WARM...DRY AND BREEZY DAY TODAY WILL COMBINE WITH THE VERY DRY
FINE DEAD FUELS /DUE TO LACK OF RECENT PRECIPITATION/ TO PRODUCE
DANGEROUS FIRE WEATHER CONDITIONS ACROSS WESTERN AND NORTH CENTRAL
NEW YORK. TEMPERATURES WILL RISE INTO THE MID 70S TO LOWER 80S
AWAY FROM THE LAKE SHORES. AFTERNOON RH VALUES WILL FALL INTO THE
25 TO 30 PERCENT RANGE...AND WINDS WILL INCREASE TO 10 TO 20 MPH
WITH GUSTS 25 TO 35 MPH. GIVEN THE DOWNWARD TREND IN FORECAST RH
VALUES AND GUSTY AFTERNOON WINDS...FEEL THE WEATHER THRESHOLDS
HAVE BEEN MET OVER A LARGER AREA THAN DISCUSSED YESTERDAY...THUS
HAVE ISSUED A RED FLAG WARNING FOR ALL OF WESTERN AND NORTH
CENTRAL NEW YORK.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...RED FLAG WARNING FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
     NYZ001>008-010>014-019>021-085.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS
         EVENING FOR SLZ022-024.

&&

$$

SYNOPSIS...CHURCH
NEAR TERM...CHURCH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...CHURCH
MARINE...CHURCH
FIRE WEATHER...CHURCH



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