Area Forecast Discussion
Issued by NWS Buffalo, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBUF 022147
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
547 PM EDT SUN AUG 2 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OFF THE MID ATLANTIC COAST TONIGHT. A
STRONG COLD FRONT WILL THEN SHIFT ACROSS NEW YORK ON MONDAY WITH
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 MONDAY/...
HIGH PRESSURE CENTERED ACROSS THE MID-ATLANTIC REGION WILL MOVE OFF
THE COAST TONIGHT AS A COLD FRONT STRETCHED ACROSS THE WESTERN GREAT
LAKES APPROACHES THE FORECAST AREA. A TIGHT PRESSURE GRADIENT
BETWEEN THESE TWO FEATURES WILL KEEP BREEZY TO GUSTY WINDS WITH
MAINLY CLEAR TO PARTLY CLOUDY SKIES MOST OF THIS EVENING. THE
BUFFALO RADAR IS SHOWING A STRONG BOWING CONVECTIVE SEGMENT JUST
WEST OF LAKE ONTARIO APPROACHING THE GREATER TORONTO AREA WHICH WAS
TRIGGERED BY A SHORTWAVE TROUGH SHIFTING ACROSS A BROAD MID-LEVEL
TROUGH RUNNING WEST TO EAST ACROSS THE GREAT LAKES. RECENT MESOSCALE
GUIDANCE INCLUDING THE HRRR/WRF/SSEO AND NAM ALL GENERALLY DISSIPATE
THIS LINE OF STORMS AS IT TRACKS ACROSS LAKE ONTARIO OVERNIGHT. THIS
DISSIPATION IS LIKELY DUE TO THE CONVECTION MOVING INTO A MORE
STABLE AND MUCH DIRER AIRMASS IN PLACE ACROSS UPSTATE NEW YORK AND
LAKE ONTARIO ALONG WITH ENCOUNTERING STRONG PARALLEL WIND SHEAR FROM
A LOW LEVEL JET FORECAST TO INCREASE AHEAD OF THE COLD FRONT.

THE FORECAST FEATURES A LOWER END CHANCE OF SOME SHOWERS AND
THUNDERSTORMS POSSIBLY REACHING WESTERN NY TOWARD MIDNIGHT FAVORING
THE MESOSCALE MODELS BUT THE BULK OF SHOWER AND THUNDERSTORM
ACTIVITY SHOULD HOLD OFF UNTIL THE LATE OVERNIGHT HOURS...CLOSER TO
DAYBREAK WHEN THE COLD FRONT APPROACHES CLOSER TO THE FORECAST AREA.
THE GUSTY/BREEZY WINDS OVERNIGHT WILL PREVENT TEMPERATURES IN MOST
AREAS FROM FALLING BELOW THE UPPER 60S OR LOWER 70S. AS THE PRESSURE
GRADIENT INCREASES OVERNIGHT...WINDS ACROSS THE HIGHER ELEVATIONS OF
THE SOUTHERN TIER AND CLOSE TO LAKE ERIE COULD GUST TO 35 MPH.

THE COLD FRONT WILL CONTINUE ACROSS THE REGION DURING THE DAY ON
MONDAY. DEWPOINT POOLING AHEAD OF THE FRONT WILL BOOST SURFACE
DEWPOINTS INTO THE MIDDLE TO UPPER 60S...MID AND UPPER LEVEL TEMPS
WILL FALL SLIGHTLY WITH THE APPROACH OF THE UPPER TROUGH ...AND LOW
LEVEL CONVERGENCE ALONG THE FRONT WILL PROVIDE LIFT AND INSTABILITY
TO SUPPORT CONVECTION. STRONG WINDS TOPPING THE BOUNDARY LAYER EARLY
MONDAY WILL ALSO PROVIDE A SEVERE WEATHER THREAT WITH DAMAGING WIND
RISK...LESSENING AS THE STRONG WINDS MOVE FARTHER ALOFT BEHIND THE
FRONT. TEMPERATURES DURING MONDAY WILL CLIMB TO THE UPPER 70S TO
LOWER 80S PRIOR TO THE FRONTAL PASSAGE.

&&

.SHORT TERM /MONDAY NIGHT 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 /22Z SUNDAY THROUGH FRIDAY/...
HIGH PRESSURE NOSING NORTHEAST FROM THE UPPER OHIO VALLEY WILL KEEP
FAIR VFR CIGS IN PLACE THROUGH AT LEAST THIS EVENING. A STRONG LINE
OF STORMS NEAR CYYZ SHOULD REMAIN NORTH OF THE FORECAST AREA. A 50KT
LOW LEVEL JET IS FORECAST TO DEVELOP AHEAD OF AN APPROACHING COLD
FRONT SHIFTING EAST FROM THE WESTERN GREAT LAKES. THIS LOW LEVEL JET
WILL BRING A FEW HOURS OF LOW LEVEL WIND SHEAR TO THE TAF SITES
OVERNIGHT.

WHILE VFR CONDITIONS WILL REMAIN IN PLACE FOR MUCH OF THE
NIGHT...ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS DEVELOPING AHEAD
OF THE APPROACHING COLD FRONT COULD IMPACT THE REGION CLOSER TO 12Z
MONDAY.

THUNDERSTORMS WILL ACCOMPANY THE COLD FRONTAL PASSAGE ON MONDAY.
THERE MAY BE LOWER MVFR TO IFR CONDITIONS WITH THE STORMS...AS WELL
AS THE RISK OF SEVERE CATEGORY WIND GUSTS...BUT MOST OF THE TIME
WILL BE VFR.

OUTLOOK...

MONDAY NIGHT AND 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 20 KNOTS TONIGHT AS A
TIGHT PRESSURE GRADIENT IS IN PLACE AHEAD OF A STRONG COLD FRONT
APPROACHING FROM THE WESTERN GREAT LAKES. AN AREA OF STRONG
THUNDERSTORMS OUT WELL AHEAD OF THE FRONT WILL MOVE ACROSS LAKE
ONTARIO TRACKING EAST TOWARD THE SAINT LAWRENCE RIVER THIS EVENING.
THIS LINE OF STORMS IS FORECAST TO WEAKEN/DISSIPATE AS IT MOVES
ACROSS THE LAKE BUT DOES BRING THE POTENTIAL FOR VERY STRONG WIND
GUSTS AND LIGHTNING.

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.

THE COLD FRONT WILL MAKE ITS WAY ACROSS THE LOWER GREAT LAKES MONDAY
MORNING...WITH 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 MONDAY FOR LEZ020.
         SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT MONDAY NIGHT FOR
         LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR LOZ030.
         SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT MONDAY NIGHT FOR
         LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT MONDAY NIGHT FOR
         LOZ042.

&&

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.