Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 300949
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
549 AM EDT THU JUL 30 2015

.SYNOPSIS...
A COLD FRONT WILL CROSS WESTERN NEW YORK THIS MORNING ALONG WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. IN THE WAKE OF
THE FRONT...COOLER AND LESS HUMID CONDITIONS WILL THEN FOLLOW FOR
THE SECOND HALF OF TODAY ON THROUGH THE END OF THE WORK WEEK AND
UPCOMING WEEKEND...WHEN THERE MAY BE SOME ADDITIONAL SCATTERED
SHOWERS AND THUNDERSTORMS AT TIMES.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 0945Z...HAVE ISSUED AN INTERMEDIATE FORECAST UPDATE TO KEEP
THINGS IN LINE WITH RECENT OBSERVATIONAL TRENDS...WHICH NOW
SUGGEST THAT THE COLD FRONT IS LOCATED OVER THE GENESEE
VALLEY...WITH ITS ASSOCIATED CONVECTION HAVING CLEARED EXTREME FAR
WESTERN NEW YORK. THROUGH THE COURSE OF THIS MORNING...THE FRONTAL
BOUNDARY WILL CROSS THE REMAINDER OF THE AREA FROM WEST TO
EAST...WITH THIS FEATURE AND ITS ASSOCIATED CONVECTION LIKELY
CLEARING OUR REGION BY AROUND LUNCHTIME. EXPECT SCATTERED TO
NUMEROUS SHOWERS AND STORMS TO CONTINUE TO ACCOMPANY THE FRONT AS
IT PASSES THROUGH OUR REGION.

IN THE WAKE OF THE FRONT...STRONG DRYING AND SYNOPTIC-SCALE SUBSIDENCE
SHOULD LEAD TO FAIRLY RAPID CLEARING FROM WEST TO EAST...YIELDING A
RETURN TO MOSTLY SUNNY SKIES AREAWIDE BY EARLY AFTERNOON. THE
COMBINATION OF THE RETURNING SUNSHINE AND MODEST COOL AIR ADVECTION
WILL ALLOW FOR GOOD MIXING TO DEVELOP...WHICH IN TURN WILL LEAD TO
THE DEVELOPMENT OF BREEZY CONDITIONS...PARTICULARLY DOWNWIND OF THE
LAKES WHERE SOME GUSTS TO 25-30 MPH WILL BE LIKELY THIS AFTERNOON.
WITH THE GOOD MIXING AND 850 MB TEMPS REMAINING IN THE VICINITY OF
+15C TO +17C INTO THIS AFTERNOON...DAYTIME HIGHS WILL STILL MANAGE TO
REACH THE LOWER TO MID 80S IN MOST PLACES TODAY...THOUGH CONDITIONS
WILL TURN NOTICEABLY LESS HUMID AS DEWPOINTS DROP INTO THE UPPER 50S
AND LOWER 60S.

TONIGHT...EXPECT FAIR AND DRY WEATHER ALONG WITH DIMINISHING WINDS AS
HIGH PRESSURE OVER THE TENNESSEE AND OHIO VALLEYS CONTINUES TO RIDGE
NORTHEASTWARD INTO OUR REGION. WITH A SOMEWHAT COOLER AND LESS HUMID
AIRMASS IN PLACE...NIGHTTIME LOWS WILL RANGE FROM THE UPPER 50S ACROSS
INTERIOR SECTIONS OF THE SOUTHERN TIER/NORTH COUNTRY TO THE LOWER TO
MID 60S ACROSS THE REST OF THE REGION...WITH THE WARMEST READINGS
FOUND ALONG THE IMMEDIATE LAKESHORES.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
THE SUB TROPICAL RIDGE PREVIOUSLY CENTERED OVER TEXAS AND THE
LOWER MISSISSIPPI VALLEY WILL RETROGRADE TO NEW MEXICO AND THE
SOUTHERN ROCKIES DURING THIS PERIOD. MEANWHILE...A PHASED LONGWAVE
TROUGH WILL BE FOUND OVER THE LOWER GREAT LAKES AND EASTERN
CANADA. THIS WILL ESTABLISH A DEEP CYCLONIC FLOW OVER OUR FORECAST
AREA WITH MARGINALLY `COOLER` AIR EXPECTED. THE NEWSWORTHY HEAT
THAT HAS BEEN SO PREVALENT IN THE EAST WILL PUSH TO THE WESTERN
STATES.

WHILE DRY WEATHER WILL BE IN PLACE FOR OUR REGION FOR MUCH OF
THIS PERIOD...DIFFICULT TO TIME MID LEVEL DISTURBANCES CRUISING
SOUTHEAST INTO THE AFOREMENTIONED LONGWAVE TROUGH WILL GENERATE
SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS. WILL GENERALLY COVER
THIS ACTIVITY WITH CHC POPS AS THERE IS A FAIR AMOUNT OF
DISAGREEMENT EXPRESSED BETWEEN THE VARIOUS GUIDANCE PACKAGES.

A FAIRLY STRONG SHORTWAVE WILL CROSS THE UPPER GREAT LAKES DURING
THE DAY FRIDAY WHILE GENERAL SUBSIDENCE WILL BE FOUND ACROSS OUR
FORECAST AREA. THIS WILL SUPPORT DRY WEATHER FOR THE BULK OF THE
DAY...BUT AS WE GET DEEPER INTO THE AFTERNOON...A LINE OF
CONVECTION TRAILING SOUTH FROM THE MID LEVEL DISTURBANCE WILL
APPROACH THE IAG FRONTIER AND THOUSAND ISLANDS REGION.
TEMPERATURES FRIDAY WILL GENERALLY CLIMB INTO THE UPPER 70S TO
LOWER 80S.

THE MID LEVEL DISTURBANCE WILL TRACK BY TO OUR NORTH FRIDAY NIGHT
WHILE AN ASSOCIATED WEAK SFC FRONTAL BOUNDARY WILL PUSH ACROSS OUR
FORECAST AREA. THIS MAY VERY WELL BE OUR HIGHEST CHANCE FOR PCPN
DURING THIS PERIOD...AS THERE SHOULD BE ENOUGH FORCING WITHIN A
FAIRLY UNSTABLE AIRMASS TO GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS. WHILE OUR REGION HAS DRIED OUT CONSIDERABLY DURING
THE PAST WEEK OR TWO...UNFORTUNATELY THIS BOUNDARY IS NOT EXPECTED
TO PRODUCE MORE THAN A TENTH OF AN INCH OF RAIN FOR MOST AREAS.

THE NEXT SHORTWAVE WILL TAKE AIM ON OUR REGION ON SATURDAY.
AGAIN... WHILE SCATTERED SHOWERS AND THUNDERSTORMS ARE
ANTICIPATED...THE MAJORITY OF THE DAY SHOULD BE RAIN FREE. ANY
CONVECTION WILL HAVE TO BE CLOSELY WATCHED THOUGH...AS A WEST TO
NORTHWEST FLOW ALOFT (NOTORIOUS FOR SUPPORTING STRONG TO SEVERE
STORMS BECAUSE OF THE RESULTING GREATER SHEARED ENVIRONMENT) WILL
BE IN PLACE. SUBSIDENCE AND LOW LEVEL RIDGING IN THE WAKE OF THE
EXITING SHORTWAVE WILL PROMOTE FAIR WEATHER WITH CLEARING SKIES
SATURDAY NIGHT.

WEAK LOW LEVEL RIDGING SHOULD BE ABLE TO SUPPORT GENERALLY DRY
WEATHER ON SUNDAY...BUT GIVEN THE CYCLONIC FLOW AND UNCERTAINTY OF
THE TIMING OF ADDITIONAL SHORTWAVES...AN AFTERNOON SHOWER OR
THUNDERSTORM CANNOT BE RULED OUT. TEMPERATURES ON SUNDAY SHOULD
TOP OUT WITHIN A FEW DEGREES OF 80.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
THE GENERAL LONGWAVE PATTERN OF HAVING A RIDGE IN THE WEST AND A
TROUGH IN THE EAST WILL REMAIN IN PLACE THROUGH AT LEAST THE MIDDLE
OF NEXT WEEK. THIS WILL KEEP TEMPERATURES CLOSE TO SEASONAL NORMALS
WITH HIGHS IN THE UPPER 70S TO LOWER 80S WHILE OVERNIGHT LOWS RANGE
FROM THE LOWER 60S MONDAY NIGHT TO THE 50S FOR TUESDAY AND WEDNESDAY
NIGHTS. IN TERMS OF RAINFALL...MORE SUBTLE SHORTWAVES ROTATING
THROUGH THE BASE OF THE TROUGH WILL ENCOURAGE ALTERNATING PERIODS OF
SHOWERS AND THUNDERSTORMS...ALTHOUGH FAIR DRY WEATHER SHOULD
DOMINATE THE PERIOD.

&&

.AVIATION /10Z THURSDAY THROUGH MONDAY/...
A WEAK COLD FRONT WILL PUSH ACROSS WESTERN AND NORTH CENTRAL NEW
YORK THIS MORNING...ALONG WITH SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS. SOME BRIEF/LOCALIZED REDUCTIONS IN FLIGHT
CONDITIONS TO IFR/MVFR WILL BE POSSIBLE WITHIN THIS ACTIVITY AS IT
PASSES THROUGH THE REGION...OTHERWISE CONDITIONS WILL REMAIN
PREDOMINANTLY VFR.

FOLLOWING THE PASSAGE OF THE COLD FRONT...VFR CONDITIONS ARE THEN
EXPECTED TO PREVAIL THROUGH THE BALANCE OF TODAY AND
TONIGHT...WITH BREEZY CONDITIONS LATE THIS MORNING AND THIS
AFTERNOON GIVING WAY TO LIGHTER WINDS BY THIS EVENING.

OUTLOOK...
FRIDAY THROUGH MONDAY...MAINLY VFR WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
A WEAK COLD FRONT WILL CROSS THE REGION THIS MORNING ALONG WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. LOCALLY HIGHER
WINDS AND WAVES WILL BE POSSIBLE WITHIN/NEAR ANY CONVECTION...WITH
RELATIVELY BENIGN CONDITIONS PREVAILING ELSEWHERE.

FOLLOWING THE PASSAGE OF THE COLD FRONT...A BRISK WESTERLY FLOW
WILL SET UP ACROSS LAKE ERIE AND EASTERN PORTIONS OF LAKE
ONTARIO/ADJOINING PORTIONS OF THE SAINT LAWRENCE RIVER...
RESULTING IN ADVISORY-LEVEL CONDITIONS IN THESE AREAS. FOR THIS
REASON...SMALL CRAFT ADVISORIES REMAIN IN EFFECT AS OUTLINED
BELOW.

AFTER THAT...HIGH PRESSURE OVER THE OHIO AND TENNESSEE VALLEYS
WILL GRADUALLY RIDGE NORTHEASTWARD TOWARD THE LOWER LAKES TONIGHT
AND FRIDAY...RESULTING IN A MODEST SOUTHWESTERLY TO WESTERLY FLOW
THAT SHOULD GENERALLY REMAIN BELOW ADVISORY LEVELS. THE ONE
EXCEPTION TO THIS MAY BE ON LAKE ERIE DURING FRIDAY...WHEN WINDS
AND WAVES MAY AGAIN APPROACH OR REACH LOWER-END ADVISORY CRITERIA.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 2 AM EDT
         FRIDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM NOON TODAY TO 11 PM EDT THIS
         EVENING FOR LEZ020.
         SMALL CRAFT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS
         EVENING FOR LOZ045.
         SMALL CRAFT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS
         EVENING FOR SLZ022.

&&

$$

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



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