Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 112342
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
742 PM EDT FRI JUL 11 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN PLACE TONIGHT WITH PARTLY CLOUDY SKIES.
AS THE HIGH MOVES OFF THE NEW ENGLAND COAST ON SATURDAY...IT WILL
BECOME WARMER AND NOTICEABLY MORE HUMID WITH A CHANCE OF A FEW
SPOTTY SHOWERS TOWARD CENTRAL NEW YORK. MORE ACTIVE WEATHER CAN THEN
BE EXPECTED FROM SUNDAY THROUGH TUESDAY AS A SERIES OF COLD FRONTS
CROSS OUR REGION WITH SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH SATURDAY/...
SATELLITE IMAGERY EARLY THIS EVENING SHOWING THE LAST OF THE DIURNAL
CUMULUS ACROSS THE INTERIOR SOUTHERN TIER AND WESTERN FINGER LAKES.
THIS MAY HANG ON A LITTLE LONGER THAN NORMAL INTO THE EVENING WITH
SOME REMNANT LOW LEVEL MOISTURE APPARENT IN MODEL GUIDANCE.

TONIGHT THE HIGH PRESSURE SHIFTS EAST OVER NEW ENGLAND. THE NAM IS
VERY AGGRESSIVE WITH LOW LEVEL MOISTURE FIELDS AROUND 850MB
TONIGHT...BUT SEEMS MUCH OVERDONE. WITH THIS IN MIND...THE CUMULUS
OVER THE SOUTHERN TIER AND FINGER LAKES SHOULD MOSTLY DISSIPATE BY
LATE EVENING. THICK CIRRUS UPSTREAM OVER THE CENTRAL LAKES WILL
SPILL QUICKLY EAST INTO THE REGION FROM WEST TO EAST TONIGHT...WITH
INCREASING HIGH CLOUDS. SOME LIMITED RIVER VALLEY FOG WILL FORM
AGAIN TONIGHT IN THE TYPICAL LOCATIONS OF THE SOUTHERN TIER. EXPECT
LOWS TO RANGE FROM THE LOWER 60S ON THE LAKE PLAINS OF WESTERN NY TO
THE MID 50S IN THE COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE
ONTARIO...WITH THE TUG HILL/WESTERN ADIRONDACKS DROPPING INTO THE
UPPER 40S TO LOWER 50S.

ON SATURDAY AN INCREASING SOUTHWEST FLOW WILL BOOST DEWPOINTS FROM
THE FINGER LAKES EASTWARD INTO THE LOWER TO MID 60S WHILE ACROSS
WESTERN NEW THEY HOLD AROUND 60. THE COMBINATION OF THE HIGHER
MOISTURE WITH DIURNAL HEATING AND A WEAK SHORTWAVE ARRIVING ALOFT
WILL BRING A LOW CHANCE OF WIDELY SCATTERED SHOWERS AND SLIGHT
CHANCE OF A THUNDERSTORM ACROSS CENTRAL NEW YORK. OTHERWISE ANOTHER
DRY DAY WITH PARTLY CLOUDY SKIES IS EXPECTED ALTHOUGH A LITTLE
WARMER AND MORE HUMID THAN TODAY. EXPECT HIGHS TO PUSH INTO THE
LOW TO MID 80S EXCEPT ALONG THE LAKE SHORES AND TUG HILL.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
EARLY SATURDAY NIGHT ANY LINGERING SHOWERS WILL DIMINISH THROUGH THE
EVENING HOURS. ATTENTION WILL TURN TO THE WEST WHERE A QUICK MOVING
AND LOW AMPLITUDE SHORTWAVE WILL BE MOVING EASTWARD FROM THE CENTRAL
PLAINS. AT THE SURFACE A WARM FRONT WILL BE LIFTING NORTHEASTWARD
ACROSS THE OHIO VALLEY...WITH MOISTURE IN THE LOW LEVELS ALSO
INCREASING ACROSS WESTERN NEW YORK. THIS INCREASING MOISTURE IN AN
ISENTROPIC FLOW AHEAD OF THE SHORTWAVE WILL LIKELY BRING RAIN
SHOWERS TO FAR WESTERN NEW YORK IN THE PREDAWN HOURS SUNDAY MORNING.

ON SUNDAY EXPECT AN AREA OF SHOWERS AND THUNDERSTORMS TO CROSS THE
STATE OF NEW YORK FROM WEST TO EAST. MODEST INSTABILITY WILL
MAINTAIN THE CHANCES FOR SCATTERED THUNDERSTORMS ON SUNDAY.
THERMODYNAMICS ARE NOT OVERLY IMPRESSIVE...BUT A STRONG LOW LEVEL
WIND FIELD WILL ALLOW FOR SOME POTENTIAL THAT STRONGER WIND GUSTS TO
BE MIXED DOWN TO THE SURFACE. THOUGH THE BULK OF THE THUNDERSTORMS
WILL LIKELY BE YOUR TYPICAL GARDEN VARIETY A DAMAGING WIND GUST
CANNOT BE RULED OUT. A SURGE OF MOISTURE AHEAD OF THE SHORTWAVE WILL
ALSO ALLOW THESE THUNDERSTORMS TO BECOME EFFICIENT RAINMAKERS WITH
PWATS RISING TO 1.50 TO 1.75 INCHES AND THE WARM CLOUD LEVEL RISING
TO 12-13K FEET.

SUNDAY NIGHT AND MONDAY THE REGION WILL REMAIN IN A WARM A SOMEWHAT
MUGGY AIRMASS. CONVECTION WILL BE POSSIBLE SUNDAY NIGHT AND
MONDAY...BASED SOMEWHAT WHAT BOUNDARIES FROM UPSTREAM CONVECTION
THAT DRIVE ACROSS THE LOWER LAKES. WILL CONTINUE WITH CHANCE POPS
FOR NOW AS NO SPECIFIC LIFTING MECHANISM CAN BE TIMED FOR PRODUCING
LIFT THIS TIME PERIOD.

MONDAY NIGHT THE GFS DRIVES A COLD FRONT ACROSS THE CWA...WHILE THE
ECMWF LINGERS A WARM AND MUGGY AIRMASS. WILL SIDE WITH THE ECMWF
SOLUTION FOR NOW...WITH A SLOWER COLD FRONT PASSAGE. THIS WILL LEAVE
THE REGION WARM OVERNIGHT WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
OVER THE COURSE OF THIS TIME PERIOD...TUESDAY TO FRIDAY...WE WILL
TRANSITION FROM A WARM AND HUMID AIRMASS WITH SCATTERED
THUNDERSTORMS TO AN UNSEASONABLY COOL AIRMASS WITH INSTABILITY
SHOWERS AND EVEN THE THREAT OF SOME LAKE ENHANCED RAIN.

TUESDAY AN AMPLIFIED PATTERN WILL BE FOUND ACROSS NORTH AMERICA WITH
AN UPPER LEVEL RIDGE ACROSS THE ROCKIES WESTWARD...AND A -3SD TROUGH
OF LOW PRESSURE DROPPING SOUTH FROM CANADA INTO THE NORTHERN PLAINS
AND WESTERN GREAT LAKES.

THERE IS STILL CONSIDERABLE MODEL DIFFERENCES WITH THE TIMING OF THE
COLD FRONT...AS LIKELY ADDITIONAL SURFACE WAVES ALONG THE FRONT WILL
SLOWLY THE PASSAGE OF THE FRONT IN THIS AMPLIFIED PATTERN. THE 12Z/11
GFS CONTINUES TO BRING THE COLD FRONT ACROSS THE REGION 12-15 HOURS
EARLIER THAN THE 00Z/11 ECMWF.

THERE LIKELY WILL STILL BE ONE MORE DAY OF SUMMER-LIKE WEATHER
TUESDAY WITH TEMPERATURES CLIMBING INTO THE LOWER 80S ALONG WITH
SUMMERY HUMIDITY LEVELS. A COLD FRONT WILL SWEEP ACROSS THE CWA
TUESDAY AND SHOWERS AND THUNDERSTORMS WILL BE LIKELY ALONG THIS
FRONTAL BOUNDARY. THOUGH THERMODYNAMICS (LITTLE CAPE/POOR LAPSE
RATES) ARE NOT THAT IMPRESSIVE WITH THIS SYSTEM THERE WILL BE
IMPRESSIVE KINEMATICS (60+ KNOTS OF 0-6 KM BULK SHEAR) AND DYNAMICS
(UPPER LEVEL SHORTWAVE/RIGHT ENTRANCE REGION OF 250 HPA JET) THAT
WILL MAINTAIN THUNDERSTORM POTENTIAL...WHICH COULD TRANSPORT
STRONGER WIND GUSTS DOWN TO THE SURFACE.

TUESDAY EVENING THE COLD FRONT WILL BE EXITING EASTWARD FROM CENTRAL
NEW YORK WITH THE SHOWERS AND THUNDERSTORMS FOLLOWING SUITE. WILL
LEAVE ISOLATED SHOWER POTENTIAL ACROSS THE CWA THE REMAINDER OF THE
NIGHT WITH THE DEEP UPPER LEVEL TROUGH NEARING.

ON WEDNESDAY AN UNSEASONABLY COOL AIRMASS WILL INVADE THE EASTERN
GREAT LAKES AS THE UPPER LEVEL TROUGH OF LOW PRESSURE ADVANCES
EASTWARD. TEMPERATURES AT 850 HPA WILL DROP TO AROUND +7C OVER LAKE
ONTARIO AND +8C OVER LAKE ERIE. LAKE TEMPERATURES ARE AROUND 22C ON
LAKE ERIE...AND 19-20C ON LAKE ONTARIO. THIS COOL AIRMASS OVER THE
WARM LAKE WATERS WILL LIKELY TRIGGER LAKE EFFECT CLOUDINESS...AND ON
A WESTERLY FLOW POSSIBLY LAKE EFFECT RAIN SHOWERS. WILL PLACE HIGHER
CHANCES FOR RAIN SHOWERS IN THE TYPICAL HIGHER TERRAIN EAST OF BOTH
LAKES WHERE AN ADDITIONAL COMPONENT OF OROGRAPHIC LIFT WILL BRING
HIGH CHANCES FOR RAIN SHOWERS. ELSEWHERE WILL CONTINUE WITH LOW
CHANCE POP FOR SCATTERED DAYTIME INSTABILITY SHOWERS UNDER THE UPPER
LEVEL LOW.

WEDNESDAY NIGHT EXPECT A REDUCTION IN PRECIPITATION ACROSS THE
REGION WITH THE LOSS OF DAYTIME HEATING. ANY CLEARING WILL BRING
COOL OVERNIGHT LOWS IN THE 40S. HOWEVER ANY LINGERING LAKE
CLOUDINESS WILL LIMIT THE RADIATIONAL LOSS OF HEAT AND KEEP
OVERNIGHT LOWS IN THE 50S.

THURSDAY THE UPPER LEVEL LOW WILL ADVANCE NORTHEASTWARD TOWARDS
JAMES BAY...WITH A SHORTWAVE SPOKE OF LOW PRESSURE OVER THE EASTERN
GREAT LAKES REGION. AGAIN WITH SIMILAR 850 HPA TEMPERATURES CHANCES
FOR RAIN SHOWERS WILL CONTINUE...ESPECIALLY EAST OF THE LAKES WHERE
LAKE ENHANCEMENT/OROGRAPHIC LIFT RAIN SHOWERS WILL MORE LIKELY.

FRIDAY WARMER AIR TO THE SOUTH WILL BEGIN TO PUSH NORTHWARD BEHIND
THE DEPARTURE OF THE UPPER LEVEL TROUGH. THIS WILL END THE LAKE
EFFECT RAIN CHANCES...AND WITH LESS DAYTIME INSTABILITY...AND THE
PRESENCE OF SURFACE HIGH PRESSURE A RETURN TO SUNSHINE AND MORE
SUMMER-LIKE AIR TEMPERATURES WILL OCCUR. WITH THIS SUNSHINE
AFTERNOON HIGHS WILL RISE INTO THE MID TO UPPER 70S ACROSS THE
REGION.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR WILL PREVAIL IN MOST AREAS FOR THE 00Z TAF CYCLE. HIGH PRESSURE
OVER THE LOWER LAKES WILL DRIFT EAST ACROSS NEW ENGLAND TONIGHT AND
OFF THE EAST COAST ON SATURDAY. DIURNAL CUMULUS ACROSS THE SOUTHERN
TIER AND FINGER LAKES SHOULD SLOWLY DIMINISH THIS EVENING. NAM MODEL
GUIDANCE KEEPS ABUNDANT LOW LEVEL MOISTURE IN PLACE NEAR 5K FEET
OVERNIGHT...BUT THIS SEEMS WAY OVERDONE. OTHERWISE A RATHER DENSE
SHIELD OF CIRRUS UPSTREAM ACROSS THE CENTRAL LAKES WILL PUSH EAST
INTO THE REGION LATER THIS EVENING. THIS MAY TEND TO THIN SOME AS IT
MOVES INTO A MID LEVEL RIDGE AND SUBSIDENCE...BUT SHOULD STILL BRING
SOME BKN CIRRUS LEVEL CIGS OVERNIGHT. SOME LIMITED RIVER VALLEY FOG
WILL FORM ACROSS THE WESTERN SOUTHERN TIER IN THE TYPICAL LOCATIONS
WITH LOCAL IFR...BUT THIS SHOULD AVOID KJHW.

ON SATURDAY ANY EARLY MORNING RIVER VALLEY FOG IN THE SOUTHERN TIER
WILL QUICKLY BURN OFF. CIRRUS SHOULD THIN FROM WEST TO EAST DURING
THE EARLY MORNING AS THE BATCH OF UPPER LEVEL MOISTURE PUSHES INTO
NEW ENGLAND. THIS WILL JUST LEAVE SCT DIURNAL CUMULUS FROM LATE
MORNING THROUGH THE AFTERNOON. CUMULUS MAY BECOME A LITTLE MORE
WIDESPREAD FROM THE FINGER LAKES INTO CENTRAL NY...WHERE A BRIEF
ISOLATED SHOWER CANNOT BE RULED OUT.

OUTLOOK...
SUNDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS AND ASSOCIATED BRIEF MVFR/IFR. GREATEST COVERAGE OF
THUNDERSTORMS WILL BE LATE SATURDAY NIGHT AND SUNDAY AND AGAIN
MONDAY NIGHT OR TUESDAY WITH A PASSAGE OF COLD FRONTS.
WEDNESDAY...MAINLY VFR WITH SCATTERED SHOWERS AND ASSOCIATED BRIEF
MVFR CIGS.

&&

.MARINE...
FAIR WEATHER WITH LIGHT WINDS WILL PERSIST ACROSS THE LOWER GREAT
LAKES AND ST LAWRENCE VALLEY THROUGH AT LEAST SATURDAY...AS HIGH
PRESSURE WILL SLOWLY DRIFT EAST ACROSS OUR REGION.

RECREATIONAL BOATERS SHOULD TAKE ADVANTAGE OF THE CURRENT SPELL OF
FAIR WEATHER...AS THE PLEASANT CONDITIONS WILL DETERIORATE SATURDAY
NIGHT AND PARTICULARLY ON SUNDAY AS THE NEXT FRONTAL SYSTEM WILL
TAKE AIM ON THE REGION. SHOWERS AND THUNDERSTORMS WILL BECOME LIKELY
BY SUNDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...HITCHCOCK/SMITH
NEAR TERM...HITCHCOCK/SMITH
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...HITCHCOCK/SMITH
MARINE...SMITH




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