Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 301922
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
322 PM EDT WED JUL 30 2014

.SYNOPSIS...
THE FALL LIKE WEATHER PATTERN THAT WE HAVE BEEN IN THE PAST COUPLE
DAYS WILL GRADUALLY MODIFY AS WE PUSH THROUGH THURSDAY AND FRIDAY.
IN THE MEANTIME...THE COOL UNSTABLE AIRMASS WILL SUPPORT AN
OCCASIONAL SHOWER OR THUNDERSTORM...WHICH COULD BE ENHANCED BY THE
WARMER WATERS OF THE LOWER GREAT LAKES.

&&

.NEAR TERM /THROUGH THURSDAY/...
THE ANOMALOUSLY DEEP LONGWAVE TROUGH THAT HAS BEEN PARKED OVER THE
EASTERN HALF OF THE CONTINENT THE PAST 48 HOURS WILL GRADUALLY FILL
AND LIFT OUT TO THE NORTHEAST...BUT NOT UNTIL THE END OF THE WEEK.
IN THE MEANTIME...THE ASSOCIATED AIRMASS WILL SLOWLY MODIFY FROM THE
MID SUMMER SUN...SO WE CAN AT LEAST LOOK FORWARD TO SOMEWHAT HIGHER
TEMPERATURES.

DIGGING A LITTLE DEEPER INTO THE DETAILS...THERE ARE TWO MORE
SHORTWAVES EMBEDDED WITHIN THE DEEP CYCLONIC FLOW THAT WILL HAVE TO
ROTATE ACROSS OUR FORECAST AREA. THE FIRST WILL CROSS OUR REGION
DURING THE FIRST HALF OF TONIGHT...BUT WITH SOME MID LEVEL DRYING
AND UNFAVORABLE DIURNAL TIMING...THIS FEATURE IS NOT EXPECTED TO
GENERATE MUCH (IF ANY) IN THE WAY OF PCPN.

THE SECOND SHORTWAVE IS NOTABLY MORE ROBUST. IT IS CURRENTLY (AS OF
20Z) CIRCULATING SOUTHWEST FROM LAKE SUPERIOR AND WILL MAKE ITS WAY
ACROSS THE LOWER GREAT LAKES LATE TONIGHT AND EARLY THURSDAY. THIS
FEATURE WILL INTERACT WITH FAVORABLE MESOSCALE LAKE EFFECT
PARAMETERS (CONV CLOUD DEPTH >30K FT AND FAIRLY STEEP LAPSE RATES
THROUGH H70 TO GENERATE SOME SHOWERS AND THUNDERSTORMS. THE BULK OF
THIS ACTIVITY WILL COME DURING THE WEE HOURS OF THURSDAY MORNING
THROUGH THE MIDDAY HOURS...AFTER WHICH TIME SUBSIDENCE IN THE WAKE
OF THE SHORTWAVE AND DIURNAL MIXING WILL END THE ACTIVITY FROM WEST
TO EAST. AS WITH THE CONVECTION THAT OCCURRED EARLIER TODAY...SOME
OF THE STORMS COULD CONTAIN SOME SMALL HAIL.

TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THURSDAY. OVERNIGHT
LOWS TONIGHT WILL BE IN THE 50S AWAY FROM THE LAKES...WHILE DAYTIME
HIGHS ON THURSDAY WILL RANGE FROM 70 TO 75. THESE VALUES WILL BE
MORE THAN 5 DEG F BELOW NORMAL END OF JULY NORMALS.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
THURSDAY NIGHT AND FRIDAY... THE LONGWAVE TROUGH WILL TEMPORARILY
DE-AMPLIFY AND RETREAT INTO CENTRAL AND NORTHERN QUEBEC. AT THE
SURFACE A WEAK RIDGE OF HIGH PRESSURE WILL BUILD FROM THE OHIO
VALLEY TO OFF THE EAST COAST. THIS WILL ALLOW THE AREA TO FINALLY
DRY OUT WITH AT LEAST PARTIAL CLEARING THURSDAY NIGHT AND SOME
SUNSHINE ON FRIDAY. 850MB TEMPS WILL RECOVER TO AROUND +14C BY
FRIDAY AFTERNOON...AND THIS WILL SUPPORT A RETURN TO SUMMER WARMTH
WITH HIGHS IN THE LOWER 80S AT LOWER ELEVATIONS AND UPPER 70S
ACROSS HIGHER TERRAIN.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE LONGWAVE TROUGH WILL RELOAD OVER THE WEEKEND AS ANOTHER DEEP
TROUGH IS CARVED OUT OVER THE GREAT LAKES AND OHIO VALLEY ON
SATURDAY...THEN MOVING EAST ON SUNDAY. THIS WILL BRING ANOTHER
PERIOD OF UNSETTLED WEATHER AS INCREASING SOUTHERLY FLOW TRANSPORTS
ATLANTIC AND GULF MOISTURE NORTHWARD AND BACK INTO OUR REGION. A
SERIES OF SUBTLE SHORTWAVES WILL LIFT NORTHEASTWARD ALONG THE
EASTERN EDGE OF THE LONGWAVE TROUGH AND COMBINE WITH INCREASING
MOISTURE AND INSTABILITY TO PRODUCE SCATTERED SHOWERS AND
THUNDERSTORMS BOTH SATURDAY AND SUNDAY. IT STILL APPEARS IN LATEST
MODEL GUIDANCE THAT THE BEST COVERAGE OF CONVECTION WILL BE ACROSS
THE HIGHER TERRAIN...WITH LESSER COVERAGE ON THE LAKE PLAINS.

BY MONDAY THIS LATEST TROUGH AMPLIFICATION WILL RETREAT BACK INTO
QUEBEC WITH WEAK HIGH PRESSURE BUILDING INTO THE OHIO VALLEY AND
LOWER LAKES. THIS SHOULD PROVIDE A RETURN TO MAINLY DRY WEATHER.
BOTH THE GFS AND ECMWF THEN SHOW A WEAK MID LEVEL TROUGH CROSSING
THE GREAT LAKES BY TUESDAY WITH THE NEXT CHANCE OF SCATTERED SHOWERS
AND STORMS.

TEMPERATURES WILL REMAIN NEAR AVERAGE THROUGH THE LONG TERM WITH
HIGHS GENERALLY IN THE LOWER 80S AT LOWER ELEVATIONS MOST DAYS WITH
MODERATE HUMIDITY RETURNING.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
WHILE VFR CONDITIONS WILL BE FOUND ACROSS THE BULK OF WESTERN AND
NORTH CENTRAL NEW YORK DURING THE REMAINDER OF THE AFTERNOON...
THERE WILL BE SCATTERED THUNDERSTORMS OVER THE REGION. THIS
CONVECTION WILL WEAKEN AND DISSIPATE WITHIN A COUPLE HOURS OF
SUNSET.

A NEW ROUND OF THUNDERSTORMS WILL DEVELOP OVER THE FAR WESTERN
COUNTIES LATE TONIGHT...WHEN CIGS AT KJHW ARE EXPECTED TO DROP TO
IFR LEVELS. THE SHOWERS AND THUNDERSTORMS WILL THEN DRIFT EAST
ACROSS ALL OF WESTERN AND NORTH CENTRAL NEW YORK DURING THE COURSE
OF THURSDAY.

OUTLOOK...
THURSDAY NIGHT AND FRIDAY...VFR.
SATURDAY AND SUNDAY...MAINLY VFR WITH CHANCE SHOWERS AND
THUNDERSTORMS.
MONDAY...VFR.

&&

.MARINE...
AN UNSEASONABLY COOL AIRMASS OVER THE WARM WATERS OF LAKES ERIE AND
ONTARIO HELPED TO GENERATE SOME LAKE INDUCED SHOWERS LAST NIGHT...
AND DURING THE COURSE OF THE NEXT 24 TO 30 HOURS...WILL ALSO BE
FAVORABLE FOR THE DEVELOPMENT OF WATERSPOUTS.

THIS FORECAST IS SUPPORTED BY THE EXCELLENT GUIDANCE OFFERED BY THE
SZILAGYI NOMOGRAM. OUR H85 TEMPS IN THE VCNTY OF 8C COMBINED WITH A
CONVECTIVE CLOUD DEPTH IN EXCESS OF 30K SUGGESTS THE POSSIBILITY OF
WATERSPOUTS. THESE HAVE BEEN IN THE FORECAST FOR SOME TIME NOW AND
WILL REMAIN IN PLACE. ANY SHOWERS THAT DEVELOP WILL THUS CARRY THE
RISK OF ALSO HAVING A WATERSPOUT.

WHILE WINDS AND WAVES ON LAKE ONTARIO WILL REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA THROUGH THURSDAY...SOUTHWEST WINDS ON LAKE ERIE
HAVE INCREASED TO THE POINT WHERE A SHORT LIVED SCA HAS BEEN ISSUED.
WINDS ON LK ERIE WILL THEN DROP OFF RATHER QUICKLY THIS EVENING...
WITH MINIMAL WINDS AND WAVES EXPECTED OVERNIGHT AND THURSDAY.

MARINERS SHOULD BE ALERT TO SHORT FUSED SPECIAL MARINE WARNINGS THAT
ARE BASED ON HEAVY SHOWERS OR THUNDERSTORMS THAT COULD BEAR
WATERSPOUTS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ040-
         041.

&&

$$

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







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