Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 271917
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
317 PM EDT WED MAY 27 2015

.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE REGION EARLY TONIGHT.
HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT THURSDAY...THEN MOVE
OFF THE NEW ENGLAND COAST FRIDAY. A SHARP COLD FRONT IS EXPECTED
TO PUSH THROUGH THE REGION OVER THE WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
A MID LEVEL TROUGH WILL BE SWINGING THROUGH THE GREAT LAKES
TONIGHT WHILE A SURFACE LOW OVER ONTARIO PULLS A COLD FRONT
ACROSS WESTERN NEW YORK LATE TONIGHT. THIS WILL FINALLY PROVIDE
SOME SURFACE BASED FORCING TO A WARM AND HUMID AIRMASS THATS BEEN
IN PLACE FOR THE PAST SEVERAL DAYS.

SEVERAL FINER RESOLUTION MODELS SUGGESTING A PRE-FRONTAL TROUGH
WILL SLIDE THROUGH A FEW HOURS AHEAD OF THE COLD FRONT. THIS
FEATURE APPEARS TO IGNITE A LINE OF CONVECTION AROUND 00Z INTO
WESTERN NEW YORK BEFORE THE COLD FRONT SLIDES THROUGH AFTER 02Z
PRODUCING ANOTHER LINE OF CONVECTION. THOUGH NOT COMPLETELY OUT OF
THE QUESTION...FEEL THE THREAT FOR SEVERE WEATHER WILL BE RATHER
LIMITED DESPITE A WATCH BOX UPSTREAM. SHEAR PROFILES AND MID
LEVEL LAPSE RATES ARE BOTH WEAK AND THE PRE-FRONTAL TROUGH AND
COLD FRONT WILL BE WORKING THROUGH THE ATMOSPHERE AFTER
INSTABILITY HAS BEEN MAXIMIZED. BEST CHANCES FOR STRONGER
THUNDERSTORMS WOULD LIKELY BE WITH THE PRE-FRONTAL TROUGH THIS
EVENING.

ONCE THE FRONT PUSHES THROUGH THE THREAT FOR CONVECTION WILL
DIMINISH. COOLER AND DRIER AIR WILL MOVE IN OVERNIGHT WITH LOWS IN
THE MID 50S TO LOWER 60S.

RISING HEIGHTS WILL CONTINUE TO PUSH ACROSS THE GREAT LAKES REGION
DURING THE DAY ON THURSDAY. PLENTY OF DRY AIR AND SUBSIDENCE WILL
PROVIDE A FAIR WEATHER DAY. HIGH MAINLY IN THE LOWER TO MID
70S...BUT LIKELY REMAINING THE THE UPPER 60S ACROSS THE NORTH
COUNTRY.

&&

.SHORT TERM /THURSDAY NIGHT 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 WEDNESDAY/...
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 /19Z WEDNESDAY THROUGH MONDAY/...
VFR FLIGHT CONDITIONS ACROSS WNY LATE THIS AFTERNOON. A GUSTY
SOUTHWEST BREEZE OVER FAR WNY INCLUDING KIAG/KBUF WITH GUSTS UP TO
30 KNOTS. THIS EVENING A COLD FRONT WILL NEAR THE REGION FROM THE
WEST. REMAINING INSTABILITY AND LINGERING MOISTURE COMBINED WITH
LIFT FROM A PRE-FRONTAL TROUGH WILL BRING A ROUND OF SHOWERS AND
POSSIBLE THUNDERSTORMS TO WNY THIS EVENING. THIS ACTIVITY WILL CARRY
EASTWARD WITH THE COLD FRONT AND WEAKEN THROUGH TONIGHT.

SOME MVFR CIGS ARE POSSIBLE TONIGHT IN PASSING SHOWERS. SOME
RESTRICTION IN FOG WILL BE POSSIBLE LATE TONIGHT FOR AREA WHICH
RECEIVE RAINFALL THIS EVENING.

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 AND MONDAY...MAINLY VFR.

&&

.MARINE...
SOUTHWEST WINDS OF UP TO 20 KNOTS WITH GUSTS APPROACHING 30 KNOTS
WILL BE FOUND INLAND THROUGH EARLY EVENING...INCLUDING THE
NIAGARA RIVER AND THE SAINT LAWRENCE RIVER. A SMALL CRAFT ADVISORY
WILL BE MAINTAINED FOR THESE AREAS. ELSEWHERE THE COOLER AND
STABLE LAKE WATERS WILL KEEP WINDS AND WAVES BELOW ADVISORY
CRITERIA.

THERE WILL BE A VEERING TO THE WINDS TO WESTERLY TONIGHT
FOLLOWING A COLD FRONTAL PASSAGE. SHOWERS AND A FEW THUNDERSTORMS
WILL BE POSSIBLE AS THIS FEATURE MOVES THROUGH WITH THE POTENTIAL
FOR LOCALLY HIGHER WIND AND WAVES.

THERE IS VERY LITTLE COLD AIR BEHIND THE 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.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ020.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         SLZ022-024.

&&

$$

SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...LEVAN
LONG TERM...LEVAN/RSH
AVIATION...TMA
MARINE...TMA



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