Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 280251
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1051 PM EDT SUN JUL 27 2014

.SYNOPSIS...
LOW PRESSURE ACROSS EASTERN MICHIGAN WILL PIVOT AROUND AN UPPER
LEVEL DISTURBANCE...REACHING EASTERN NEW YORK STATE MONDAY MORNING. THIS
WILL BRING HEAVY RAINS TO PORTIONS OF WESTERN NEW YORK...WITH SOME
EMBEDDED THUNDERSTORMS. RAIN WILL LAST INTO MONDAY AND THEN A COOLER
PATTERN WILL SET UP FOR THE FIRST HALF OF THE WORK WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
REGIONAL RADARS THIS EVENING DISPLAY AN AREA OF HEAVY RAIN AND
EMBEDDED THUNDER JUST NOW EXPANDING EASTWARD ACROSS THE NIAGARA
RIVER AND INTO THE NORTHERN NIAGARA FRONTIER. THIS ACTIVITY IS
FORMING ALONG A CONVERGENT BOUNDARY OF NORTHERLY WINDS FROM ACROSS
LAKE ONTARIO AND SOUTHWESTERLY WINDS AHEAD OF THE SURFACE LOW. SLOW
MOVEMENT TO THESE CELLS WILL BRING LOCALIZED HEAVY RAIN THROUGH THE
LATE EVENING AND EARLY MORNING HOURS. THIS ACTIVITY WILL LIKELY
EXPAND EASTWARD ALONG THE SOUTHERN SHORE OF LAKE ONTARIO AS
CONVERGENT WINDS FORM THROUGH THE OVERNIGHT.

SCATTERED SHOWERS AND SOME THUNDERSTORMS ARE ALSO FOUND ELSEWHERE
THROUGHOUT WESTERN NEW YORK THIS LATE EVENING. THE MAIN SPOKE OF
MODERATE TO HEAVY RAIN AND THUNDER ASSOCIATED WITH UPWARD LIFT AHEAD
OF AN UPPER LEVEL TROUGH AXIS IS NOW ACROSS CENTRAL LAKE ERIE AND
WESTERN PENNSYLVANIA. THIS ACTIVITY IS MORE MODERATE RAIN THAN HEAVY
RAIN AT THIS POINT IN TIME.

EXPECT THIS BAND OF PRECIPITATION TO OUR WEST TO SLOWLY ROTATE
ACROSS MUCH OF THE CWA THROUGH THE OVERNIGHT TIME PERIOD. THERE MAY
BE A BRIEF UPTICK IN PRECIPITATION RATES OVERNIGHT AS MOISTURE IS
PULLED NORTHWARD INTO THE BAND OF RAIN AND WILL LEAVE THE MENTION OF
HEAVY RAIN IN THE GRID FOR NOW. THIS BAND OF RAIN IN ADDITION TO THE
AREA OF HEAVY RAIN AND THUNDER ACROSS THE NORTHERN NIAGARA FRONTIER
WILL BRING A HALF TO ONE INCH OF RAIN THROUGH THE OVERNIGHT...WITH
LOCALIZE HIGHER AMOUNTS.

THIS SURFACE LOW WILL TRACK EASTWARD THROUGH THE NIGHT TO ABOUT
SOUTHERN CENTRAL NEW YORK BY DAYBREAK. THERE LIKELY WILL BE STEADY
RAIN STILL FALLING ACROSS NORTHERN WESTERN NEW YORK AROUND DAYBREAK
AS A DEFORMATION BAND OF RAIN FALLS TO THE NORTHWEST OF THE SURFACE
LOW. ADDITIONAL RAIN MONDAY WILL RANGE BETWEEN A HALF TO ONE
INCH...GIVING MUCH OF THE REGION ONE TO TWO INCHES OF RAIN FOR A
12-18 HOUR PERIOD. OF COURSE LOCALIZED HEAVIER AMOUNTS OF 2 INCHES+
ARE LIKELY WITHIN HEAVIER AND POSSIBLE TRAINING CELLS...AS WELL AS
SOME AREAS NOT TOPPING THE ONE INCH MARK DUE TO THE SCATTEREDNESS OF
CONVECTION.

BEHIND THIS SURFACE LOW MONDAY MORNING MODERATE NORTHERLY FLOW WILL
BE IN PLACE...WITH GUSTS TO 25 MPH. THIS UPSLOPE COMPONENT COMBINED
WITH COOLER TEMPERATURES ALOFT AND UPPER LEVEL TROUGHING WILL CAUSE
CLOUDS AND POSSIBLY SHOWERS TO LINGER FOR MUCH OF THE DAY. RAIN WILL
TAPER OFF FROM WEST TO EAST THROUGH THE AFTERNOON HOURS ACROSS THE
CWA. COOLER AIR AND CLOUDS KEEP TEMPERATURES IN THE 60S ON
MONDAY...WHICH IS UNSEASONABLY COOL FOR THIS TIME OF YEAR. THESE
READINGS ARE MORE TYPICAL OF MID SEPTEMBER GIVING THE FALLISH FEEL
TO THE AIR. HOWEVER ABOUT HALF OF JULY`S IN RECENT DECADES FOR BOTH
BUFFALO AND ROCHESTER HAVE AT LEAST ONE DAY WITH HIGHS ONLY IN THE
60S...SO THIS COOL COUPLE OF DAYS ARE NOT ANYTHING EXTREME.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
COOL AIR WILL REMAIN ACROSS THE EASTERN GREAT LAKES ON MONDAY
NIGHT...BUT THE DRIER AIR ALOFT AND SUBSIDENCE WILL SUPPRESS ANY
LAKE EFFECT RESPONSE OTHER THAN A THIN LAYER OF LAKE INDUCED
STRATOCU TO THE SOUTHEAST OF LAKES ERIE AND ONTARIO. EXPECT A COOL
AND DRY NIGHT WITH LOWS IN THE MID 40S TO NEAR 50 ACROSS THE
INTERIOR OF THE SOUTHERN TIER AND THE TUG HILL PLATEAU...TO THE MID
TO UPPER 50S ALONG THE SHORES OF LAKES ERIE AND ONTARIO.

IT WILL BE A LITTLE WARMER ON TUESDAY WITH HIGHS N THE MID/UPR 60S
INLAND TO THE LOWER 70S ALONG THE LAKESHORES AND LOWER TERRAIN.
HOWEVER...THE WARMER SURFACE TEMPS COINCIDE WITH A COOLING ALOFT TO
AROUND +5C AT 850MB AS THE AXIS OF THE PERSISTENT CANADIAN TROUGH CROSSES
THE REGION. THIS WILL YIELD THE CHANCE OF DAYTIME SHOWERS ON TUESDAY
WITH SOME NIGHTTIME LAKE EFFECT RAIN TUESDAY NIGHT...AND EVEN THE
ISOLATED RISK OF WATERSPOUTS.

THE LOW CHANCE OF DIURNAL CYCLE SHOWERS CONTINUES ON WEDNESDAY AS
THE UPPER TROUGH ROTATES ANOTHER SPOKE OF VORTICITY ACROSS THE
REGION. THE HIGH TEMPS WILL BUMP UP ANOTHER NOTCH...TO THE UPPER 60S
TO MID 70S...SO WILL BRING BACK A CHANCE OF THUNDERSTORMS DURING
WEDNESDAY AFTERNOON. THE 850MB TEMPS WARM SUFFICIENTLY TO EXCLUDE
THE RISK OF WATERSPOUTS. WEDNESDAY NIGHT WILL BE LESS COOL WITH
OVERNIGHT LOWS IN THE 50S ACROSS THE REGION...AND A LOW CHANCE OF AN
OVERNIGHT SHOWER AS WELL.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE DEEP LONGWAVE TROUGH OVER THE GREAT LAKES AND NORTHEASTERN STATE
DURING MIDWEEK WILL SLOWLY DE-AMPLIFY AND RETREAT INTO QUEBEC BY THE
END OF THE WEEK. THE LOW CHANCE OF SHOWERS ON THURSDAY WILL GIVE WAY
TO NIL POPS ON THU NIGHT AND FRIDAY. HIGH TEMPS WILL RISE FROM MID
70S THURSDAY TO THE UPPER 70S ON FRIDAY.

THE SLOW WARMING TREND WILL CONTINUE ON SATURDAY...BUT A CLOSED LOW
DEVELOPING OVER THE OHIO VALLEY MAY FORCE ATLANTIC MOISTURE TO
SPREAD NORTH INTO OUR REGION WITH A CHANCE OF SHOWERS AND A FEW
THUNDERSTORMS SATURDAY AND SUNDAY AFTERNOONS.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AT 00Z SEVERAL SEGMENTS OF HEAVY SHOWERS AND THUNDERSTORMS WERE
FOUND FROM THE CENTRAL GREAT LAKES AND OHIO VALLEY...ADVANCING
EASTWARD TOWARDS WESTERN AND CENTRAL NEW YORK. THESE SEGMENTS AS
THEY CONTINUE EASTWARD WILL BRING PERIODS OF HEAVY RAIN AND
SCATTERED THUNDERSTORMS TO THE REGION THROUGH THE NEXT 12 TO 15
HOURS. EXPECT VFR CONDITIONS TO DETERIORATE AND FLUCTUATE INTO IFR
OR LOWER RANGE FOR A PERIOD OF TIME WITHIN THESE HEAVIER PERIODS OF
RAIN AND THUNDER. AS THE FLOW BECOMES MORE NORTHERLY LATE TONIGHT
EXPECT IFR CIGS TO DEVELOP ACROSS WESTERN NEW YORK.

RAIN WILL EXIT EASTWARD TOMORROW WITH MVFR/IFR FLIGHT CONDITIONS
IMPROVING BACK TO VFR LATE IN THE TAF PERIOD.

OUTLOOK...
TUESDAY THROUGH THURSDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
FRIDAY...VFR.

&&

.MARINE...
LOW PRESSURE WILL PIVOT SOUTH OF THE REGION TONIGHT AND THEN WILL
STRENGTHEN ACROSS EASTERN NEW YORK ON MONDAY. THIS WILL TIGHTEN THE
PRESSURE GRADIENT AND ESTABLISH A MODERATE NORTHERLY FLOW LATE
TONIGHT AND MONDAY. THIS FLOW WILL SUPPORT SMALL CRAFT HEADLINES FOR
ALL OF LAKE ONTARIO....LAKE ERIE AND THE NIAGARA RIVER FROM LATE
TONIGHT THROUGH TOMORROW.

WINDS WILL DIMINISH MONDAY NIGHT...WITH A WEAKER FLOW FORECAST FOR
MID-WEEK. COOLER TEMPERATURES ALOFT SUGGEST THERE IS A CHANCE FOR
WATERSPOUTS ON TUESDAY NIGHT INTO WEDNESDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR NYZ001>004-010>014-
     019>021-085.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 2 PM EDT MONDAY FOR LEZ020.
         SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM EDT MONDAY FOR
         LEZ040-041.
         SMALL CRAFT ADVISORY FROM 5 AM TO 2 PM EDT MONDAY FOR
         LOZ030.
         SMALL CRAFT ADVISORY FROM 2 AM TO 8 PM EDT MONDAY FOR
         LOZ042>044.
         SMALL CRAFT ADVISORY FROM 5 AM TO 6 PM EDT MONDAY FOR
         LOZ045.

&&

$$

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






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