Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 030607
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
207 AM EDT MON AUG 3 2015

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL WORK ACROSS THE FORECAST AREA AHEAD
OF A COLD FRONT OVERNIGHT. THE COLD FRONT WILL THEN SHIFT ACROSS NEW
YORK ON MONDAY WITH ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS
POSSIBLE THROUGH MONDAY AFTERNOON. A COMFORTABLY COOL AIRMASS WILL
THEN FOLLOW THE FRONT MONDAY NIGHT AND SHOULD BE SETTLE IN PLACE FOR
THE REMAINDER OF THE WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
A LINEAR MCS THAT WAS FOUND OVER MICHIGAN AND SOUTHERN ONTARIO AT
MIDNIGHT HAS SINCE PUSHED SOUTH ACROSS LAKE ERIE...WHILE WEAKER
CONVECTION HAS MADE ITS WAY OVER LAKE ONTARIO TO THE THOUSAND
ISLANDS REGION. THE LATTER CONVECTION WILL CONTINUE TO WEAKEN DURING
THE REMAINING PRE DAWN HOURS WHILE 40 TO 50KT WINDS BASED
AROUND 4K FT WILL PUSH THE BULK OF THE TRAILING STRATIFORM RAIN OVER
SOUTHERN ONTARIO TO THE NORTH. SIMPLIFYING THIS...THE VAST MAJORITY
OF OUR FORECAST AREA WILL REMAIN DRY FOR THE OVERNIGHT WITH ONLY THE
FAR WESTERN COUNTIES AND THE THOUSAND ISLANDS REGION HAVING THE RISK
FOR ANY THUNDERSTORM ACTIVITY. TEMPERATURES WILL REMAIN ELEVATED...
WITH READINGS HOLDING NEARLY STEADY IN THE 70S ACROSS THE LAKE
PLAINS WHILE TEMPS WILL BE IN THE MID TO UPPER 60S IN THE SRN TIER.

AS WE PUSH PAST DAYBREAK...THE WEAKENED CONVECTION OVER SOUTHERN
ONTARIO WILL PUSH EAST AND START TO ADVANCE ACROSS OUR FORECAST
AREA. THE COLD FRONT RESPONSIBLE FOR FORCING THIS CONVECTION HAS
BEEN SLOW TO MOVE EAST BECAUSE OF EMBEDDED WAVES...BUT NOW THAT THE
LAST OF THESE WAVES HAS PASSED...THE FRONT SHOULD PICK UP SPEED
DURING THE COURSE OF THE DAY.

THE CONVECTION WILL BE SPOTTY AND WEAK FOR THE FIRST PART OF
TODAY...THEN AS DAYTIME INSTABILITY MOUNTS...THE ACTIVITY SHOULD
STRENGTHEN EAST OF THE GENESEE VALLEY. IN FACT...THE STORM
PREDICTION CENTER HAS OUTLINED MOST OF WESTERN NEW YORK WITHIN A
SLIGHT RISK FOR SEVERE STORMS...AGAIN...WITH THE GREATEST CHANCE
COMING EAST OF THE GENESEE VALLEY WHERE SBCAPES OF 1000-2000 J/KG
COULD BE REALIZED. GIVEN THE UNIDIRECTIONAL...SPEED SHEARED
ENVIRONMENT...THE GREATEST SEVERE WEATHER THREAT WILL COME FROM
DAMAGING STRAIGHT LINE WINDS.

TEMPERATURES LATER TODAY WILL CLIMB TO THE UPPER 70S TO LOWER 80S.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
WATER VAPOR IMAGERY THIS AFTERNOON NICELY DISPLAYS A SHORTWAVE
TROUGH OF LOW PRESSURE REACHING NORTHERN MINNESOTA. THIS SHORTWAVE
WILL BE FORCING A SURFACE COLD FRONT EASTWARD ACROSS OUR REGION
MONDAY NIGHT. EXPECT SHOWERS AND THUNDERSTORMS TO END THROUGH THE
EVENING HOURS WITH THE PASSAGE OF THE COLD FRONT AND LOSS OF
DAYTIME INSTABILITY.

THIS SHORTWAVE TROUGH WILL ALSO DRAW A PERSISTENT UPPER LEVEL LOW
OVER EASTERN CANADA SOUTHWARD. ON TUESDAY A POOL OF COOL AIR ALOFT
WILL BE RESIDING OVER SOUTHERN CANADA AND THE GREAT LAKES REGION.
STEEPENING LAPSE RATES THROUGH THE DAY TUESDAY WILL LIKELY BRING
SCATTERED RAIN SHOWERS THROUGH THE PEAK HEATING OF THE AFTERNOON AND
EARLY EVENING HOURS. THIS COOL AIR ALOFT MAY EVEN BRING SOME LAKE
ENHANCED RAIN SHOWERS TO SE AND E OF LAKE ONTARIO WHERE +6 TO +8C AT
850 HPA WILL BE FLOWING OVER A +22C OR SO LAKE TEMPERATURE.

ON WEDNESDAY THE UPPER LEVEL LOW WILL REMAIN NEARBY THE GREAT LAKES
REGION...HOWEVER LOW LEVEL MOISTURE WILL BE MUCH LESS. EVEN THOUGH
INSTABILITY WILL AGAIN INCREASE THROUGH THE AFTERNOON HOURS THE
LESS PLENTIFUL MOISTURE WITHIN THE ATMOSPHERE SHOULD DECREASE THE
AMOUNT OF AFTERNOON SHOWERS. GREATEST CHANCES FOR A SHOWER WEDNESDAY
WILL BE ACROSS OUR EASTERN ZONES WHICH WILL HAVE SLIGHTLY BETTER
MOISTURE PROFILES.

WEDNESDAY NIGHT SHOWERS SHOULD DIMINISH WITH THE LOSS OF DAYTIME
HEATING AND THE INCREASING STABILITY OF THE ATMOSPHERE.

TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL FOR DAYTIME
HIGHS THIS PERIOD...WHILE OVER NIGHT LOWS WILL AVERAGE A FEW DEGREES
BELOW NORMAL.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE FEATURE OF NOTE TO START THIS TIME PERIOD IS PRESENTLY FOUND
OVER THE STATE OF NEVADA AS A SHORTWAVE SLOWLY RIDES NORTHWARD
ALONG THE WESTERN FLANK OF A LONG RANGE RIDGE. TIMING THIS FEATURE
OVER THE ROCKIES...AND NORTHERN PLAIN STATES WILL BRING THE NEXT
WIDESPREAD THREAT OF SHOWERS AND THUNDERSTORMS INTO THE REGION
FRIDAY. THERE MAY BE A FEW STORMS THURSDAY AHEAD OF THIS FEATURE
NEAR THE STATE LINE...BUT BOTH THE 12Z GFS AND 12Z ECMWF SUGGEST
THAT FRIDAY WILL BE THE BEST DAY FOR PRECIPITATION CHANCES. WILL
MAINTAIN LOW CHANCE POPS FRIDAY AS THE MODELS CONTINUE A HIGH
DEGREE OF UNCERTAINTY TO THIS SHORTWAVE TRACK...POSSIBLY TRACKING
FARTHER SOUTHWARD WHICH WOULD LEAVE FRIDAY DRY...ESPECIALLY OUR
NORTHERN ZONES.

THIS SHORTWAVE MAY DRAW THE UPPER LEVEL LOW OVER EASTERN CANADA BACK
SOUTHWARD...LEAVING CHANCES FOR SHOWERS AND THUNDERSTORMS ON
SATURDAY ACROSS WESTERN AND NORTH CENTRAL NEW YORK STATE. THESE
SHOWERS AND THUNDERSTORMS MAY LINGER INTO SUNDAY DEPENDING UPON HOW
QUICKLY THE LOWER HEIGHTS ASSOCIATED WITH THE QUEBEC LOW LINGER OVER
THE EASTERN GREAT LAKES REGION.

WITH THE UPPER LEVEL LOW OVER QUEBEC NEARBY...TEMPERATURES ARE
EXPECTED TO REMAIN JUST BELOW SEASONAL NORMALS THROUGH THIS TIME
PERIOD.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
STRONG THUNDERSTORMS HAVE PUSHED SOUTH ACROSS LAKE ERIE...BUT
ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORM ACTIVITY WILL BE
POSSIBLE LATER TODAY. THIS WILL ESPECIALLY BE THE CASE FOR SITES
SOUTH AND EAST OF THE IAG FRONTIER...POSSIBLY EFFECTING THE KJHW...
KROC AND KART TAF SITES.

OTHERWISE...VFR CONDITIONS IN PLACE AT 06Z ARE EXPECTED TO REMAIN IN
PLACE THROUGH AT LEAST MIDDAY. FOR THE AFTERNOON...WHILE VFR CIGS
ARE ANTICIPATED...THERE MAY BE TIMES WHEN MVFR CONDITIONS IN AND NEAR
CONVECTION CAN BE EXPECTED.

VFR CONDITIONS ARE EXPECTED MONDAY NIGHT IN THE WAKE OF AN EXITING
COLD FRONT.

WINDS THROUGH EARLY THIS AFTERNOON WILL GUST TO 30 KNOTS AT TIMES AT
KBUF...KIAG AND KROC...WITH SOME LOW LEVEL WIND SHEAR ALSO POSSIBLE
AT KROC BEFORE DAYBREAK.

OUTLOOK...

TUESDAY...MAINLY VFR WITH A CHANCE OF A FEW SHOWERS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
FRIDAY...CHANCE OF
THUNDERSTORMS OVER THE SOUTHERN TIER...OTHERWISE VFR.

&&

.MARINE...
SOUTHWEST WINDS WILL CONTINUE TO GUST TOWARD 35 KNOTS OVERNIGHT AS A
TIGHT PRESSURE GRADIENT IS IN PLACE AHEAD OF A STRONG COLD FRONT
APPROACHING FROM MICHIGAN. THE GUSTY WINDS ACROSS THE EASTERN GREAT
LAKES AHEAD OF THE APPROACHING COLD FRONT ARE FORECAST TO INCREASE
WAVES ON THE NORTHEASTERN END OF LAKE ERIE TOWARD 6 FEET AT TIMES.
SMALL CRAFT ADVISORIES ARE IN PLACE ACROSS LAKE ERIE AND ONTARIO TO
COVER FOR THESE HIGHER WINDS AND WAVES THROUGH MONDAY. A LINE OF
SHOWERS AND STRONG THUNDERSTORMS WILL ALSO WORK ACROSS THE LAKE ERIE
AND WESTERN LAKE ONTARIO WATERS AHEAD OF THE FRONT OVERNIGHT.

THE COLD FRONT WILL MAKE ITS WAY ACROSS THE LOWER GREAT LAKES MONDAY
MORNING...WITH ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS
POSSIBLE. THE SEVERE THREAT FROM THESE STORMS WILL BE WIND GUSTS
NEARING OR EXCEEDING 50 KNOTS. ALONG WITH THE THREAT OF
CONVECTION...SMALL CRAFT ADVISORIES WILL BE IN EFFECT ACROSS THE
LOWER GREAT LAKES FOR THE BULK OF THE DAY. WINDS WILL TEMPORARILY
SUBSIDE ACROSS THE REGION LATE MONDAY AND MONDAY NIGHT.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ020.
         SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LEZ040-
         041.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         LOZ030.
         SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
         LOZ042>045.

&&

$$

SYNOPSIS...WCH
NEAR TERM...RSH
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...RSH
MARINE...RSH/SMITH/WCH



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