Area Forecast Discussion
Issued by NWS Buffalo, NY

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810
FXUS61 KBUF 050613
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
213 AM EDT THU MAY 5 2016

.SYNOPSIS...
A DEEP UPPER LEVEL TROUGH CENTERED OVER THE UPPER GREAT LAKES WILL
GRADUALLY SETTLE ACROSS THE REGION THROUGH THE END OF THE WORK WEEK.
AS A RESULT...WE CAN EXPECT SOMEWHAT UNSETTLED WEATHER OVER THE NEXT
FEW DAYS...THOUGH TEMPERATURES WILL REMAIN FAIRLY CLOSE TO NORMAL
LEVELS FOR EARLY MAY.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 2 AM...REGIONAL RADARS SHOW THAT LINGERING SHOWERS HAVE
DIMINISHED IN COVERAGE OVER THE PAST FEW HOURS...THOUGH SOME
SPOTTY ACTIVITY IS STILL HANGING ON ACROSS WESTERN NEW YORK AND
NORTHWESTERN PA...ATTENDANT TO THE LEFTOVER INVERTED TROUGH FROM
YESTERDAY. WHILE THE MAJORITY OF THE AREA SHOULD REMAIN DRY
OVERNIGHT...THE LINGERING SURFACE TROUGH COULD STILL TOUCH OFF
A FEW MORE SPOTTY SHOWERS AS IT CONTINUES TO DRIFT WESTWARD AND
WEAKEN. OTHERWISE...EXPECT MOSTLY CLOUDY SKIES TO BE THE GENERAL
RULE OVERNIGHT...WITH LOW TEMPERATURES AVERAGING OUT IN THE MID
40S.

ON THURSDAY A MID LEVEL CLOSED LOW WILL MOVE FROM THE SOUTHERN
APPALACHIANS TO THE CAROLINA COAST WITH A WEAK INVERTED TROUGH
EXTENDING NORTHWARD TO LAKE ONTARIO. THE MAJORITY OF THE ORGANIZED
FORCING FOR ASCENT WILL FOLLOW THE CLOSED LOW INTO THE CAROLINAS...
WITH VERY WEAK PERIODS OF DPVA AND CONVERGENCE ACROSS WESTERN AND
CENTRAL NY. GIVEN THE WEAK FORCING...EXPECT ANY SHOWERS TO BE
PARTIALLY TIED TO THE DIURNAL CYCLE WITH THE GREATER CHANCES DURING
THE AFTERNOON AND EVENING ACROSS THE HIGHER TERRAIN WELL INLAND FROM
THE LAKES. COVERAGE WILL BE LOWEST ON THE LAKE PLAINS WITH SOME
STABILIZING INFLUENCE FROM THE LAKES...WITH EXTENDED RAIN FREE TIME
IN MANY AREAS. CLOUDS WILL LIMIT TEMPERATURES WITH HIGHS IN THE
LOWER 60S IN MOST AREAS THURSDAY...WITH SOME MID 60S ACROSS THE
NORTH COUNTRY WHERE SOME BREAKS IN THE CLOUDS ARE MORE LIKELY.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
CLOSED LOW OVER THE CAROLINAS AT THE START OF THE PERIOD. LATEST
MODELS CONTINUING TO SUGGEST THE GREATEST PRECIPITATION RISK
THURSDAY NIGHT AND FRIDAY WILL BE FOCUSED ALONG INVERTED
TROUGH/DEFORMATION AXIS AND DEEPER MOISTURE PIVOTING NORTHWARD
INTO THE SOUTHERN TIER AND CENTRAL NEW YORK. AREAS CLOSER TO THE
LAKES AND CANADIAN BORDER WILL LIKELY SEE LESS IN THE WAY OF
SHOWER ACTIVITY.

CLOUD COVER WILL KEEP LOWS THURSDAY NIGHT IN THE MID TO UPPER IN
MOST AREAS WITH A FEW POCKETS OF LOWER 40S ACROSS THE INTERIOR
SOUTHERN TIER AND LEWIS COUNTY. TEMPERATURES FRIDAY WILL DEPEND ON
AMOUNT OF CLOUD COVER AND SHOWER ACTIVITY WITH THE WARMEST AREAS
LIKELY TO BE ACROSS NORTHERN AREAS WITH LESS SHOWER ACTIVITY...WITH
HIGHS IN THE LOWER TO MID 60S IN MOST AREAS.

THE PESKY CLOSED LOW WILL STILL BE MEANDERING AROUND THE CAROLINAS
FRIDAY NIGHT BUT FORECAST TO WEAKEN AT THIS SAME TIME. THIS SHOULD
ALLOW ANY DIURNALLY DRIVEN SHOWERS FRIDAY TO SLOWLY WANE OVERNIGHT.
LOW TEMPERATURES GENERALLY IN THE MID TO UPPER 40S.

BY SATURDAY A NARROW RIDGE OF HIGH PRESSURE WILL BUILD INTO THE
LOWER LAKES BETWEEN THE WEAKENING CLOSED LOW AND A COLD FRONT
MOVING INTO THE CENTRAL GREAT LAKES...PROVIDING A MAINLY DRY DAY.
THERMAL RIDGE NOSING INTO THE REGION AHEAD OF THE FRONT WITH 850
MB TEMPERATURES NEARING +8C WILL SUPPORT LOWER 70S FOR INTERIOR
SECTIONS IF ENOUGH SUNSHINE IS REALIZED.

SATURDAY NIGHT A POTENT MID LEVEL TROUGH AND ASSOCIATED SURFACE
COLD FRONT WILL CROSS THE REGION. DYNAMICS CONTINUE TO APPEAR
STRONG ENOUGH WITH THIS SYSTEM TO MAINTAIN LIKELY PROBABILITIES
FROM CONTINUITY. SOME LIMITED INSTABILITY JUST AHEAD OF THE COLD
FRONT MAY PRODUCE A FEW WIDELY SCATTERED THUNDERSTORMS AS WELL.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
STRONG COLD ADVECTION BY MAY STANDARDS WILL DEVELOP BEHIND THE
COLD FRONT ON SUNDAY. THIS WILL BRING TEMPERATURES BACK TO BELOW
AVERAGE WITH HIGHS ONLY IN THE MID TO UPPER 50S IN MANY AREAS. THE
PASSAGE OF THE MID LEVEL TROUGH AND ASSOCIATED COLD MID LEVEL
TEMPERATURES MAY SUPPORT A FEW SCATTERED RAIN SHOWERS DURING SUNDAY.

HIGH PRESSURE WILL THEN BRING A RETURN TO DRY WEATHER SUNDAY NIGHT
THROUGH TUESDAY MORNING. BY TUESDAY AFTERNOON 12Z ECMWF AND GFS
BRING INCREASING MOISTURE ALONG A WARM FRONT INTO THE LOWER LAKES
TO WESTERN AND CENTRAL NY. THIS FRONT AND AN ELEVATED CHANCE OF RAIN
WILL REMAIN ACROSS THE REGION THROUGH WEDNESDAY...THEN THE FRONT IS
SUPPRESSED BACK TO THE SOUTH BY HIGH PRESSURE BUILDING IN FROM THE
NORTH. HIGH TEMPS ON TUESDAY AND WEDNESDAY WILL RUN CLOSE TO OR
SLIGHTLY ABOVE SEASONAL NORMALS IN THE MID TO UPPER 60S.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
FOR THE BALANCE OF TONIGHT...THE MAIN FORECAST ISSUE IS THE
POTENTIAL FOR THE DEVELOPMENT OF LOWER STRATUS/FOG FROM ROUGHLY
THE GENESEE VALLEY WESTWARD. WHILE MOST MODEL GUIDANCE CONTINUES
TO SUGGEST THAT THIS WILL OCCUR...IT HAS ALSO BEEN MUCH TOO QUICK
TO LOWER CIGS SO FAR...WITH REGIONAL SATELLITE IMAGERY/OBS STILL
INDICATING FAIRLY WIDESPREAD VFR CONDITIONS AS OF THIS WRITING...
WITH JUST A LITTLE MVFR NOTED ACROSS FAR INTERIOR PORTIONS OF THE
SOUTHERN TIER AND GENESEE VALLEY.

THE BETTER THAN MODELED CONDITIONS SO FAR HAVE BEEN DUE TO THE
PRESENCE OF A FAIR AMOUNT OF MID AND HIGH CLOUDS ACROSS THE REGION
TO THIS POINT...WHICH HAVE ACTED TO INHIBIT SURFACE COOLING AND
CONSEQUENTLY THE FORMATION OF ANY APPRECIABLE LOWER STRATUS/FOG.
IN ORDER FOR THE LATTER TO DEVELOP OVERNIGHT...THERE WILL LIKELY
HAVE TO BE SUFFICIENT CLEARING FOR A LONG ENOUGH PERIOD OF TIME...
A FACTOR THAT REMAINS RATHER QUESTIONABLE AT THE MOMENT.

GIVEN THE RESULTANT FORECAST UNCERTAINTY AND CURRENT OBSERVATIONAL
TRENDS...HAVE ELECTED TO HEDGE A LITTLE BIT MORE OPTIMISTIC WITH
THE 06Z TAF PACKAGE...WHICH STILL ALLOWS FOR THE DEVELOPMENT OF
SOME STRATUS OVERNIGHT FROM KROC/KDSV WESTWARD...BUT MAINLY OF
THE MVFR VARIETY AS OPPOSED TO IFR. THIS SAID...IFR CIGS REMAIN
A POSSIBILITY IF SKIES CAN MANAGE TO CLEAR OUT LONG ENOUGH.

DURING THE DAY THURSDAY...WHATEVER LOWER STRATUS/FOG THAT MANAGES
TO DEVELOP OVERNIGHT SHOULD MIX OUT BY MID TO LATE MORNING WITH
RENEWED DIURNAL HEATING. THE DAYTIME HEATING WILL ALSO LEAD TO THE
DEVELOPMENT OF SOME ADDITIONAL DIURNALLY-DRIVEN SCATTERED SHOWERS
AND POSSIBLY EVEN A THUNDERSTORM ACROSS THE SOUTHERN TIER DURING
THE AFTERNOON...ANY OF WHICH COULD PRODUCE SOME BRIEF/LOCALIZED
REDUCTIONS TO MVFR. OUTSIDE OF THE ABOVE...GENERAL VFR CONDITIONS
SHOULD PREVAIL.

THURSDAY NIGHT...EXPECT GENERAL VFR CONDITIONS TO PREVAIL...WITH
JUST SOME LINGERING SCATTERED SHOWERS/SPOTTY MVFR FOUND ACROSS THE
SOUTHERN TIER AND INTERIOR PORTIONS OF THE FINGER LAKES.

OUTLOOK...
FRIDAY...VFR/MVFR WITH SCATTERED TO NUMEROUS SHOWERS...WITH THE
GREATEST AREAL COVERAGE EXPECTED ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER AND FINGER LAKES.
SATURDAY...VFR.
SATURDAY NIGHT...SHOWERS WITH A CHANCE OF THUNDERSTORMS.
SUNDAY...MAINLY VFR WITH A CHANCE OF MORNING SHOWERS EAST OF KROC/KDSV.
MONDAY...VFR.

&&

.MARINE...
THE REMAINDER OF THE WEEK WILL FEATURE A RELATIVELY WEAK PRESSURE
GRADIENT ACROSS THE LOWER LAKES REGION. THIS WILL RESULT IN LIGHT
TO MODEST WINDS PREDOMINATING...ALONG WITH CORRESPONDINGLY MINIMAL
WAVES.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...APFFEL/CHURCH/JJR
SHORT TERM...TMA
LONG TERM...WCH
AVIATION...JJR
MARINE...APFFEL/CHURCH/JJR



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