Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 271134
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
734 AM EDT WED MAY 27 2015

.SYNOPSIS...
MID SUMMER`S WARMTH AND HUMIDITY WILL REMAIN ACROSS THE
EASTERN GREAT LAKES REGION FOR ANOTHER DAY. SHOWERS AND
THUNDERSTORMS WILL BLOSSOM THIS AFTERNOON...ESPECIALLY ACROSS THE
GENESEE VALLEY AND POINTS EASTWARD...WHILE WESTERN NEW YORK WILL
WAIT UNTIL A WEAK COLD FRONT PASSAGE THIS EVENING FOR MORE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FOLLOWING THIS COLD FRONT
PASSAGE LATE TONIGHT...SLIGHTLY COOLER AIR...BUT MORE NOTICEABLY
DRIER AIR WILL BE IN STORE FOR THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
A FEW SHOWERS ARE SCATTERED ACROSS
THE CWA...ESPECIALLY THE SAINT LAWRENCE VALLEY...AND WNY.

WATER VAPOR IMAGERY DISPLAYS A SHARP MID LEVEL SHORTWAVE OVER THE
WESTERN GREAT LAKES REGION...WHILE AT THE SURFACE AN AREA OF LOW
PRESSURE IS NEARING THE UP OF MICHIGAN...WITH A TRAILING WEAK COLD
FRONT OVER THE MIDWEST.

TODAY WILL AGAIN FEATURE A HUMID LATE MAY DAY AS PWATS REMAIN 1.00
TO 1.50 INCHES AND DEWPOINTS REMAIN IN THE LOW TO MID 60S.
INSTABILITY WILL INCREASE THROUGH THE DAY WITH SBCAPE VALUES RISING
TO WELL OVER 1000 J/KG...AND NEARING 1500-2000 J/KG OVER THE FINGER
LAKES REGION. THIS INSTABILITY WILL ALLOW FOR SHOWERS AND
THUNDERSTORMS TO INCREASE IN NUMBER...ESPECIALLY ACROSS THE GENESEE
VALLEY AND POINTS EASTWARD TODAY.  WIND PROFILES MAY FAVOR MORE
HEAVY RAIN AS A UNIDIRECTIONAL SOUTHWEST FLOW MAY ALLOW FOR SOME
TRAINING OF CELLS THIS AFTERNOON...THOUGH 0-6 KM BULK SHEAR VALUES
DO REACH 30 TO 35 KNOTS. OTHER THUNDERSTORM PARAMETERS OF LI`S OF -2
TO -4C ACROSS OUR EASTERN SECTIONS...AND K INDEX VALUES NEARING 37C
WILL WARRANT WATCHING THUNDERSTORMS LATER TODAY FOR SEVERE
POTENTIAL.

FEEL THE TWO BIGGEST THREATS WILL COME LATE THIS MORNING AND EARLY
AFTERNOON...WITH THESE THREATS HEAVY RAIN AND GUSTY WINDS. WILL
INSERT THIS ENHANCED WORDING INTO THE GRIDS. THE TALL SKINNY CAPE
PROFILES OF SOUNDINGS WILL KEEP THE THREAT OF HAIL MARGINAL AT BEST.
AS THE AFTERNOON PROGRESSES AND BETTER INSTABILITY AND LOW LEVEL
CONVERGENCE WITHIN THE PREFRONTAL TROUGH SHIFTS EASTWARD EXPECT THE
BETTER ORGANIZED STORMS TO BE LARGELY EAST OF OUR REGION BY LATE
AFTERNOON OR EVENING.

TO THE WEST AFTER ANY MORNING SHOWERS EXIT THE REGION EASTWARD
EXPECT SOME SUNSHINE TO DEVELOP ACROSS WNY...ESPECIALLY TO THE
NORTHEAST OF LAKE ERIE WHERE A LAKE BREEZE CIRCULATION WILL BE
DEVELOPING. AS THIS SUNSHINE INCREASES THE MIXING LEVEL HEIGHTS
GUSTY WINDS STARTING AROUND 10-11 AM WILL REACH TO AROUND 25 MPH OR
SO. ON THE EDGE OF THE LAKE BREEZES AFTERNOON INSTABILITY
THUNDERSTORMS WILL BE POSSIBLE...FIRST ACROSS SW NYS...THEN EARLY
THIS EVENING ACROSS THE NIAGARA FRONTIER WHERE ADDED CONVERGENCE
FROM A NEARING COLD FRONT WILL BE FOUND.

FOR TONIGHT ATTENTION WILL TURN TO THE COLD FRONT AND ASSOCIATED
THUNDERSTORMS. THIS COLD FRONT WILL HAVE ADDITIONAL LIFT OF A MID
LEVEL SHORTWAVE THAT WILL PASS ACROSS THE EASTERN GREAT LAKE REGION.

THE BULK OF THE CONVECTIVE SHOWER ACTIVITY WILL BE ACROSS WNY...IN
AREAS THAT DID NOT RECEIVE DAYTIME THUNDERSTORMS. EXPECT AN AREA OF
SHOWERS AND THUNDERSTORMS TO DROP SOUTHEASTWARD ACROSS WNY THROUGH
THE EVENING HOURS. WE WILL BE LOSING SOME DAYTIME
INSTABILITY...THOUGH THE EARLY EVENING ARRIVAL OF THE CONVECTION MAY
BE ABLE TO TAP INTO SOME STILL MODEST INSTABILITY TO PRODUCE A FEW
GUSTY THUNDERSTORMS THIS EVENING...ESPECIALLY OVER LAKE ERIE AND
INLAND ACROSS SOUTHERN ERIE...AND CHAUTAUQUA COUNTY. EXPECT SOME
WEAKENING AND DIMINISHMENT IN COVERAGE AREA OF THE CONVECTION AS IT
REACHES CNY WHERE LOWER INSTABILITY WILL RESIDE. WILL CONTINUE WITH
CHANCE POPS ACROSS THE FINGER LAKES AND EASTERN LAKE ONTARIO REGION.

AS THE WEAK COLD FRONT PASSES OVERNIGHT TEMPERATURES WILL NOT DROP
MUCH...BUT THE DEWPOINTS WILL. THIS FRONT WILL ERASE THE HIGH PWATS
OVER OUR REGION...AND LOWER DEW POINTS INTO THE MID TO UPPER 50S BY
DAYBREAK. A FEW SHOWERS MAY LINGER ACROSS THE EASTERN LAKE ONTARIO
REGION TOWARDS DAYBREAK...CLOSER TO THE UPPER LEVEL SHORTWAVE.

HIGHS TODAY WILL BE A MUGGY UPPER 70S TO MID 80S. IT WILL REMAIN
MUGGY AND STILL WARM THROUGH THE EVENING HOURS. THEN LATER TONIGHT
TEMPERATURES WILL DROP BEHIND THE WEAK COLD FRONT INTO THE UPPER 50S
AND LOWER 60S.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
A PROGRESSIVE FLOW FOUND OVER NORTH AMERICA WILL OFFER TWO FAIRLY
SIGNIFICANT COLD FRONTAL PASSAGES OVER THE GREAT LAKES DURING THIS
PERIOD....BUT THE BULK OF THE TIME WILL BE DOMINATED BY A STRONG
EAST COAST RIDGE. THIS WILL TRANSLATE INTO MAINLY DRY...UNEVENTFUL
WEATHER. THE GOOD NEWS FOR AGRICULTURALISTS IS THAT THE STRETCH
OF DRY WEATHER WILL LIKELY END WITH A `WET` FRONTAL PASSAGE AS
THIS TIME FRAME COMES TO A CLOSE.

A STRONG SHORTWAVE CROSSING THE UPPER GREAT LAKES TODAY WILL DRIVE
A COLD FRONT ACROSS OUR REGION LATE TONIGHT AND EARLY THURSDAY.
THE MAIN FRONT SHOULD BE THROUGH MOST OF OUR FORECAST AREA BY
DAYBREAK WITH MID LEVEL DRYING ALREADY BECOMING ESTABLISHED OVER
THE WESTERN COUNTIES. A SECONDARY FRONTAL BOUNDARY WILL SWEEP
ACROSS THE NORTH COUNTRY BY MIDDAY THOUGH...AND THIS SHOULD DELAY
THE ONSET OF FAIR WEATHER FOR THAT AREA BY SOME 3 TO 6 HOURS.
OTHERWISE...HIGH PRESSURE CENTERED IN THE VCNTY OF JAMES BAY WILL
NOSE SOUTH ACROSS THE LOWER GREAT LAKES DURING THE COURSE OF THE
DAY....WITH SUBSIDENCE AND CONTINUED DRYING LEADING TO INCREASING
AMOUNTS OF SUNSHINE. IT WILL BE COOLER AND NOTICEABLY LESS HUMID
AS WELL...AS DEWPOINTS THAT HAD BEEN IN THE 60S WILL DROP BACK
THROUGH THE 50S. AFTERNOON MAX TEMPS WILL GENERALLY BE IN THE 70S.

THURSDAY NIGHT WILL FEATURE MOONLIT SKIES AS A BURGEONING H5 RIDGE
WILL SLIDE ACROSS THE LOWER GREAT LAKES. IT WILL BE A COMFORTABLE
NIGHT WITH TEMPERATURES GENERALLY SETTLING INTO THE 50S. SITES IN
THE COOLER SRN TIER VALLEYS AND IN THE FOOTHILLS OF THE ADIRONDACKS
COULD CONCEIVABLY EXPERIENCE MINS IN THE UPPER 40S.

WARMER WEATHER WILL RETURN TO OUR FORECAST AREA ON FRIDAY...AS A
STRENGTHENING RIDGE WILL TAKE SHAPE ALONG THE EAST COAST. THE
DEEPENING SOUTHERLY FLOW FOUND BETWEEN THE ASSOCIATED OFFSHORE SFC
HIGH AND A COLD FRONT OVER THE UPPER GREAT LAKES WILL PUMP H85
TEMPS BACK INTO THE MID TEENS CELSIUS...WHICH WILL EASILY SUPPORT
AFTERNOON MAX TEMPS IN THE MID 80S FOR ALL BUT THE LAKE SHORES
AND HIGHER TERRAIN. THE ONLY FLY ION THE OINTMENT FOR FRIDAY WILL
BE THE POTENTIAL FOR A LATE AFTERNOON THUNDERSTORM IN THE VCNTY
OF A LAKE BREEZE BOUNDARY OVER THE SRN TIER. FROM THIS VANTAGE
POINT THOUGH...THE AIRMASS LOOKS LIKE IT WILL STILL BE DRY ENOUGH
TO KEEP THIS THREAT FROM BEING TOO WIDESPREAD.

AFTER A VERY MILD AND UNEVENTFUL FRIDAY NIGHT WHEN MIN
TEMPERATURES WILL HOLD IN THE MID TO UPPER 60S...IT WILL LIKELY
TURN QUITE UNSETTLED FOR SATURDAY. A SHARP COLD FRONTAL BOUNDARY
STRETCHING FROM GEORGIAN BAY AND LOWER MICHIGAN TO ABOUT CHICAGO
AT DAYBREAK SATURDAY WILL SLOWLY PRESS SOUTHEAST TO LAKES ERIE
AND ONTARIO BY EVENING. A WARM UNSTABLE AIRMASS IN ADVANCE OF THE
FRONT WILL SUPPORT THE DEVELOPMENT OF NUMEROUS SHOWERS AND
THUNDERSTORMS BY AFTERNOON...WITH A STRONG 130KT H25 JET OVER
QUEBEC REINFORCING DEEP SYNOPTIC LIFT THROUGH THE ENTIRE BOUNDARY
LAYER. THIS SHOULD RESULT IN SOME AREAS OF SIGNIFICANT DOWNPOURS
WITH RAINFALL AMOUNTS OF OVER AN INCH POSSIBLE.

HIGH PRESSURE OVER ONTARIO WILL SLOWLY PUSH THE FRONT ACROSS
WESTERN AND NORTH CENTRAL NEW YORK SATURDAY NIGHT. THE ANABATIC
NATURE OF THE SLOW MOVING COLD FRONT WILL LIKELY KEEP SHOWERS IN
PLACE SATURDAY NIGHT WHEN ANOTHER HALF INCH OR MORE OF RAIN
COULD FALL. THIS FRONTAL PASSAGE CERTAINLY HAS THE POTENTIAL TO
PRODUCE THE MOST WIDESPREAD SOAKING RAINFALL IN QUITE SOME TIME.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
ANOMALOUSLY STRONG HIGH PRESSURE WILL DRIFT ACROSS EASTERN CANADA
SUNDAY AND MONDAY...AND THIS WILL SHOVE A MOISTURE RICH COLD FRONT
FURTHER SOUTH ACROSS THE MID ATLANTIC STATES. LEFTOVER SHOWERS OVER
MUCH OF OUR REGION ON SUNDAY WILL FINALLY COME TO AN END AS A
RESULT...BUT A FAIR AMOUNT OF CLOUDS WILL LIKELY PERSIST. THIS WILL
ESPECIALLY BE THE CASE CLOSER TO THE PENNSYLVANIA BORDER.

H85 TEMPS IN THE WAKE OF THE FRONT ARE FORECAST TO BE IN THE UPPER
SINGLE DIGITS (CELSIUS)...SO SUNDAY AND MONDAY WILL FEATURE BELOW
NORMAL TEMPERATURES WITH MAX TEMPS GENERALLY IN THE 60S.

AS THE AFOREMENTIONED SFC HIGH MOVES OFF THE NEW ENGLAND COAST
MONDAY NIGHT AND TUESDAY...ITS CLOCKWISE CIRCULATION WILL OPEN
THE DOOR FOR SOMEWHAT MILDER AIR TO RETURN TO THE REGION FROM THE
UPPER OHIO VALLEY. TEMPERATURES ON TUESDAY ARE THUS FORECAST TO
CLIMB BACK INTO THE LOW TO MID 70S.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AT 12Z VFR FLIGHT
CONDITIONS...WITH EMBEDDED HIGH END MVFR FOUND ACROSS WNY...WHILE
SOME LOWER MVFR CIGS ARE FOUND ACROSS THE SOUTHERN TIER. A FEW
ISOLATED SHOWERS ARE ACROSS THE CWA THIS MORNING...AND THIS ACTIVITY
WILL BECOME MORE SCATTERED MIDDAY...AND THEN WITH THE ADDITION OF
DAYTIME HEATING POSSIBLY BLOSSOM A FEW THUNDERSTORMS OVER THE
GENESEE VALLEY AND EASTERN LAKE ONTARIO REGION THIS AFTERNOON.
EXPECT SOME RETURN TO SUNSHINE...WITH A GUSTY SOUTHWEST BREEZE OVER
FAR WNY.

THIS EVENING A COLD FRONT WILL NEAR THE REGION FROM THE WEST. AN
INCREASE IN INSTABILITY AND LINGERING MOISTURE COMBINED WITH LIFT
FROM A PASSING SHORTWAVE WILL BRING ANOTHER ROUND OF SHOWERS AND
POSSIBLE THUNDERSTORMS TO WNY THIS EVENING. THIS ACTIVITY WILL CARRY
EASTWARD WITH THE COLD FRONT THROUGH WEDNESDAY NIGHT...WEAKENING AS
IT REACHES CNY DUE TO THE LOSS OF DAYTIME HEATING.

SOME MVFR CIGS ARE POSSIBLE TONIGHT IN PASSING RAIN SHOWERS...AND
SHORTLY THEREAFTER.

OUTLOOK...
THURSDAY...MAINLY VFR WITH A LOW CHANCE OF EARLY MORNING SHOWERS
ACROSS THE NORTH COUNTRY. FRIDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN TIER AND INTERIOR
PORTIONS OF THE FINGER LAKES. SATURDAY...MAINLY VFR THOUGH SHOWERS
AND THUNDERSTORMS MAY BRING BRIEF FLIGHT RESTRICTIONS.
SUNDAY...MAINLY VFR.

&&

.MARINE...
SOUTHWEST WINDS WILL INCREASE TODAY AHEAD OF A COLD
FRONT. THESE WINDS WILL BE FOUND STRONGEST INLAND...AND WILL INCLUDE
THE NIAGARA RIVER AND THE SAINT LAWRENCE RIVER WITHIN A SMALL CRAFT
ADVISORY TODAY. HERE THESE SOUTHWEST WINDS MAY NEAR 20 KNOTS.
ELSEWHERE CONFIDENCE IS NOT HIGH ENOUGH FOR A SCA ON LAKE ERIE WHERE
WINDS MAY REMAIN AROUND 15 KNOTS OR LESS THROUGH THE DAY. THERE WILL
BE A SLIGHT VEERING TO THESE WINDS TO WESTERLY TONIGHT FOLLOWING A
COLD FRONTAL PASSAGE. THERE IS VERY LITTLE COLD AIR BEHIND THIS
FRONT AND WE DO NOT EXPECT MUCH INCREASE IN EITHER WINDS OR WAVE
HEIGHT LATER TONIGHT AND INTO THURSDAY.

EXPECT ANOTHER PERIOD OF NON SCA CONDITIONS ON THE AREA WATER BODIES
INTO THE BEGINNING OF THE WEEKEND. LATER SATURDAY SOUTHWEST WINDS
WILL INCREASE AHEAD OF A STRONGER COLD FRONT...POSSIBLY
NECESSITATING THE HOISTING OF ADDITIONAL SMALL CRAFT FLAGS ON AREA
LAKES AND RIVERS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS
         EVENING FOR LEZ020.
         SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 8 PM
         EDT THIS EVENING FOR SLZ022-024.

&&

$$

SYNOPSIS...THOMAS
NEAR TERM...THOMAS
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...THOMAS
MARINE...THOMAS



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