Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 291932
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
332 PM EDT MON JUN 29 2015

.SYNOPSIS...
WEAK HIGH PRESSURE OVER NEW YORK STATE LATE THIS AFTERNOON WILL
MOVE EAST OF THE AREA TONIGHT. LOW PRESSURE WILL LIFT ACROSS THE
GREAT LAKES TONIGHT THROUGH WEDNESDAY BRINGING MORE SHOWERS AND
POSSIBLE THUNDERSTORMS THROUGH MIDWEEK. HIGH PRESSURE WILL BUILD
INTO THE GREAT LAKES AND NORTHEAST FOR THURSDAY AND FRIDAY.

&&

.NEAR TERM /THROUGH TUESDAY/...
GENERALLY SCATTERED TO BROKEN CLOUDS WILL REMAIN OVER THE REGION
FOR THE REST OF THE AFTERNOON WITH CLOUDS INCREASING AGAIN ACROSS
THE WESTERN SOUTHERN TIER AND NIAGARA FRONTIER. CONVECTION ALONG
AND SOUTH OF THE NY-PA BORDER SHOULD MOVE EASTWARD AND STAY MAINLY
SOUTH OF THE BORDER LATE THIS AFTERNOON. OTHER CONVECTION OVER
SOUTHERN ONTARIO WILL REMAIN OVER THE NIAGARA PENINSULA THROUGH
EARLY EVENING.

NEXT SHORTWAVE TROUGH AND ATTENDANT SECOND SURFACE LOW WILL LIFT
NORTHEAST INTO LAKE ERIE TONIGHT...WHILE ALSO SPREADING INCREASING
AMOUNTS OF MOISTURE AND WARM ADVECTIVE LIFT BACK INTO OUR REGION.
THIS WILL RESULT IN MID AND HIGH CLOUD COVER INCREASING AGAIN ACROSS
FAR SOUTHWESTERN NEW YORK THIS AFTERNOON AND ACROSS THE REST OF THE
REGION TONIGHT...WITH A SIMILAR INCREASE IN SHOWER CHANCES FOLLOWING
A FEW HOURS LATER. AFTER MIDNIGHT...THE COMBINATION OF INCREASING
MOISTURE AND WARM ADVECTIVE LIFT ALONG AN ADVANCING WARM FRONT
SHOULD BECOME SUFFICIENT TO SUPPORT A LIKELIHOOD OF SHOWERS SOUTH OF
LAKE ONTARIO...ALONG WITH THE CHANCE FOR A FEW THUNDERSTORMS AS WELL
AS SOME WEAK TO MODEST ELEVATED INSTABILITY ALSO DEVELOPS.

THE LOW WILL PUSH THE WARM FRONT THROUGH OUR REGION DURING THE FIRST
HALF OF TUESDAY...WITH SHOWERS AND THUNDERSTORMS. THE BULK OF THIS
FIRST ROUND OF CONVECTION WILL BE FOUND EAST OF THE FINGER LAKES AND
EAST OF LAKE ONTARIO. WHILE THERE WILL BE THE POTENTIAL FOR A SHOWER
OR THUNDERSTORM OVER THE FAR WESTERN COUNTIES IN THE MORNING...IT
SHOULD LARGELY BE RAINFREE.

IN THE WAKE OF THE WARM FRONT...THE AIRMASS OVER THE WESTERN
COUNTIES WILL BECOME INCREASINGLY UNSTABLE DURING THE COURSE OF THE
MORNING AND MIDDAY. THIS WILL SET THE STAGE FOR THE NEXT ROUND OF
SHOWERS AND THUNDERSTORMS WHICH WILL COME THROUGH THE FORECAST AREA
DURING THE MID AND LATE AFTERNOON. AN ILL DEFINED SFC LOW WILL DRIFT
ACROSS SOUTHERN ONTARIO AT THAT TIME...WITH A PRE FRONTAL TROUGH
PASSING THROUGH OUR REGION. WHILE CONVECTION APPEARS LIKELY INLAND
AWAY FROM LAKE ERIE...THERE IS UNCERTAINTY AS TO THE AMOUNT OF CLOUD
COVER THAT WE WILL EXPERIENCE IN ADVANCE OF THE CONVECTION. THIS
WILL PLAY A SIGNIFICANT ROLE IN DETERMINING THE RISK FOR STRONG TO
SEVERE THUNDERSTORM ACTIVITY. THE GREATEST POTENTIAL FOR SIGNIFICANT
AFTERNOON CONVECTION IS OVER THE FINGER LAKES REGION AND THE SRN
TIER EAST OF JAMESTOWN.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
THE LONGWAVE TROUGH THAT HAS BEEN PARKED OVER MUCH OF EASTERN NORTH
AMERICA AND CENTERED ON THE GREAT LAKES WILL REMAIN IN PLACE THROUGH
THE PERIOD. AS A RESULT WESTERN AND NORTH-CENTRAL NEW YORK WILL
REMAIN EXPOSED TO THE PARADE OF DISTURBANCES THAT WILL CONTINUE TO
BRING PERIODS OF UNSETTLED WEATHER...WITH BREAKS IN BETWEEN
SYSTEMS...WITH TEMPERATURES THAT WILL GENERALLY RUN COOLER THAN
AVERAGE.

AS WE OPEN THE PERIOD TUESDAY NIGHT THE NEXT IN THE TRAIN OF SYSTEMS
WILL BE AFFECTING THE REGION IN THE FORM OF A SHARPLY AMPLIFIED UPPER
LEVEL TROUGH SWING ACROSS THE LOWER GREAT LAKES WITH AN ATTENDANT
SURFACE LOW TRACKING IN THE VICINITY OF LAKE ONTARIO BEFORE
LIFTING INTO QUEBEC WEDNESDAY. SHOWERS AND THUNDERSTORMS WILL BE
FAIRLY WIDESPREAD IN THE EVENING WITH THE FOCUS SHIFTING TOWARDS
THE EASTERN HALF OF THE FORECAST AREA LATER TUESDAY NIGHT AS THE
LEAD SHORTWAVE LIFTS ACROSS THE AREA. GENERALLY WEAK INSTABILITY
SHOULD NEGATE THE SEVERE THREAT...AND GIVEN THE DYNAMIC NATURE OF
THE FORCING...AM NOT EXPECTING A WIDESPREAD FLOODING THREAT
EITHER.

THE FOCUS FOR CONVECTION WILL SHIFT TO EASTERN NEW YORK WEDNESDAY AS
THE SHORTWAVE ENERGY LIFTS OUT ACROSS THE SAINT LAWRENCE VALLEY AND
NEW ENGLAND WITH THE AFOREMENTIONED SURFACE LOW MOVING OFF INTO
QUEBEC. GIVEN GOOD UPSLOPE FORCING ON WESTERLY FLOW...THE EASTERN
LAKE ONTARIO ZONES WILL HAVE A CHANCE TO SEE A FEW SHOWERS AND
POSSIBLY A THUNDERSTORM...PARTICULARLY EARLY IN THE AFTERNOON BEFORE
DEEPER MOISTURE AND SYNOPTIC FORCING DEPART THE AREA. A SOMEWHAT
DRIER AND MORE STABLE AIRMASS WILL BE MOVING INTO WESTERN NEW YORK
ON WEDNESDAY AND THIS SHOULD TAMP DOWN CONVECTION CONSIDERABLY.
THAT SAID...MODEL GUIDANCE IS PAINTING A FAIR AMOUNT OF CONVECTION
ELSEWHERE ACROSS THE REGION INCLUDING ACROSS SOUTHERN ONTARIO AND
PENNSYLVANIA AND GIVEN THAT WE WILL STILL BE UNDER THE INFLUENCE
OF THE LONGWAVE TROUGH AND ANY SUBTLE SHORTWAVES EMBEDDED IN THE
OVERALL CYCLONIC FLOW...WILL LEAVE A LOW CHANCE OF SHOWERS IN
ACROSS THE WEST FOR THE TIME BEING.

THE PAYOFF FOR THE ACTIVE WEATHER LEADING UP TO THIS POINT WILL THEN
COME WEDNESDAY NIGHT AND THURSDAY...AS FAIR WEATHER WILL SETTLE
ACROSS ALL OF OUR FORECAST AREA. WEAK...BUT EXPANSIVE SFC BASED
RIDGING WILL MOVE ACROSS THE GREAT LAKES REGION WITH SEASONABLE
TEMPERATURES AND RELATIVELY COMFORTABLE HUMIDITY LEVELS EXPECTED.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
THIS WILL GENERALLY BE AN UNEVENTFUL WEATHER PERIOD ACROSS
WESTERN AND NORTH CENTRAL NEW YORK...AS A DEAMPLIFYING UPPER LEVEL
PATTERN WILL BE FOUND ACROSS THE COUNTRY. WHILE BROAD TROUGHINESS
WILL REMAIN IN PLACE OVER THE GREAT LAKES... TEMPERATURES WILL
AVERAGE VERY CLOSE TO EARLY JULY NORMALS.

HIGH PRESSURE CENTERED OVER NORTHERN NEW ENGLAND ON FRIDAY WILL
SUPPLY ANOTHER FINE DAY ACROSS OUR REGION...AS AT LEAST PARTIAL
SUNSHINE AND H85 TEMPS IN THE VCNTY OF 12C WILL SUPPORT AFTERNOON
HIGHS IN THE UPPER 70S TO NEAR 80 (MID 70S ACROSS MUCH OF SRN
TIER).

AS THE HIGH MOVES OFF THE COAST AND RENEWED TROUGHING DIGS ACROSS
THE LOWER GREAT LAKES FRIDAY NIGHT...MOISTURE WILL MAKE AN ATTEMPT
TO PUSH TO THE NORTH ACROSS OUR REGION. THIS WILL SET THE STAGE
FOR SOME SHOWERS AND THUNDERSTORMS...MOST OF WHICH WOULD HOLD OFF
UNTIL LATER FRIDAY NIGHT.

THE TROUGH WILL THEN CROSS OUR FORECAST AREA ON SATURDAY. THIS
WILL SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY EAST OF
THE GENESEE VALLEY. FROM THIS FAR VANTAGE POINT... GUIDANCE IS
SUGGESTING THAT THE CONVECTION WILL BE EAST OF OUR AREA BY
EVENING. HIGH PRESSURE WILL FOLLOW SATURDAY NIGHT... PROMOTING
FAIR WEATHER FOR FOURTH OF JULY FIREWORKS DISPLAYS.

THE AREA OF HIGH PRESSURE WILL THEN CROSS OUR REGION ON SUNDAY
WITH FAIR WEATHER ANTICIPATED.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
GENERALLY SCATTERED TO BROKEN CLOUDS 3-5K FT WILL REMAIN OVER THE
REGION FOR THE REST OF THE AFTERNOON WITH MID AND HIGH LEVEL
CLOUDS INCREASING AGAIN ACROSS THE WESTERN SOUTHERN TIER AND
NIAGARA FRONTIER. CONVECTION ALONG AND SOUTH OF THE NY-PA BORDER
SHOULD MOVE EASTWARD AND STAY MAINLY SOUTH OF THE BORDER LATE THIS
AFTERNOON. OTHER CONVECTION OVER SOUTHERN ONTARIO WILL REMAIN OVER
THE NIAGARA PENINSULA THROUGH EARLY EVENING.

THE SURFACE RIDGE WILL SLIDE OFF TO OUR EAST EARLY THIS EVENING AND
GIVE WAY TO ANOTHER AREA OF LOW PRESSURE LIFTING ACROSS THE OHIO
VALLEY. THIS WILL RESULT IN ADDITIONAL MID AND HIGH CLOUD COVER
SPREADING INTO THE AREA FROM THE SOUTHWEST LATER THIS AFTERNOON AND
EVENING...WITH INCREASING SHOWER CHANCES RETURNING TO THE VCNTY OF
KJHW BY 00Z TUESDAY...THEN SPREADING ACROSS THE REST OF THE REGION
THROUGH THE BALANCE OF THE TAF PERIOD. AFTER MIDNIGHT...CHANCES FOR
A FEW THUNDERSTORMS WILL ALSO SPREAD ACROSS AREAS SOUTH OF LAKE
ONTARIO IN A SIMILAR FASHION AS SOME WEAK TO MODEST ELEVATED
INSTABILITY DEVELOPS. WHILE CONDITIONS WILL GENERALLY REMAIN
VFR...IT IS POSSIBLE THAT ANY SUCH SHOWERS OR THUNDERSTORMS COULD
PRODUCE SOME BRIEF REDUCTIONS TO MVFR.

CONVECTION WILL MOVE EAST THROUGH THE FINGER LAKES AND EAST OF LAKE
ONTARIO IN THE MORNING AS THE WARM FRONT MOVES THROUGH THE REGION.
A BRIEF PERIOD OF RELATIVELY DRY WEATHER WILL FOLLOW THE PASSAGE OF
THE WARM FRONT...WITH ADDITIONAL CONVECTION LIKELY AFTER 17Z TUESDAY.

OUTLOOK...
TUESDAY NIGHT...MAINLY VFR...THOUGH WITH THE LIKELIHOOD OF A FEW
ROUNDS OF SHOWERS/THUNDERSTORMS AND ATTENDANT REDUCTIONS TO MVFR.
WEDNESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
THURSDAY AND FRIDAY...VFR.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
LOW PRESSURE WILL TRACK ACROSS THE GREAT LAKES REGION TONIGHT
THROUGH WEDNESDAY. WHILE WINDS WILL FRESHEN A BIT IN ADVANCE OF
THIS SYSTEM TONIGHT AND TUESDAY...AT THIS POINT IT APPEARS THAT
CONDITIONS SHOULD REMAIN SAFELY BELOW ADVISORY LEVELS RIGHT
THROUGH THE UPCOMING WEEK. HIGH PRESSURE WILL BUILD OVER THE GREAT
LAKES THURSDAY AND FRIDAY.

&&

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

&&

$$

SYNOPSIS...FRANKLIN
NEAR TERM...FRANKLIN
SHORT TERM...RSH/WOOD
LONG TERM...RSH
AVIATION...FRANKLIN
MARINE...FRANKLIN



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