Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 010851
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
451 AM EDT MON SEP 1 2014

.SYNOPSIS...
IT WILL BE A WARM AND HUMID LABOR DAY WITH A FEW SPOTTY SHOWERS AND
THUNDERSTORMS POSSIBLE ACROSS WESTERN NEW YORK THIS AFTERNOON...BUT
THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. A COLD FRONT WILL
THEN CROSS THE REGION ON TUESDAY WITH MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE WILL THEN BUILD INTO THE LOWER LAKES
BEHIND THIS COLD FRONT AND BRING DRY WEATHER WEDNESDAY AND THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
11-3.9 MICRON SATELLITE IMAGERY SHOWS LOW STRATUS EXPANDING ACROSS
THE REGION EARLY THIS MORNING AS EXTENSIVE LOW LEVEL MOISTURE IS
TRAPPED BENEATH A WEAK SUBSIDENCE INVERSION. THERE IS SOME PATCHY
FOG AS WELL...BUT LOW LEVEL PROFILES SEEM TO SUPPORT STRATUS OVER
FOG WITH SOME MIXING IN THE BOUNDARY LAYER. EXPECT LOW STRATUS TO
LAST INTO MID MORNING IN MANY AREAS BEFORE MIXING OUT WITH THE ONSET
OF DEEPER DAYTIME MIXING. THE INVERSION IS WEAK...SO THE STRATUS
LAYER SHOULD MIX OUT QUICKLY WITH LOWER ELEVATIONS CLEARING MID
MORNING AND HIGHER TERRAIN BY LATE MORNING OR MIDDAY.

OUR REGION WILL BE MAINLY BETWEEN SYSTEMS TODAY...WITH A WEAK TROUGH
MOVING OFF THE MID ATLANTIC COAST AND THE NEXT COLD FRONT REMAINING
WELL UPSTREAM ACROSS THE WESTERN LAKES. THIS WILL LEAVE LITTLE IN
THE WAY OF SYNOPTIC SCALE FORCING...WITH MODEL GUIDANCE SHOWING JUST
A VERY WEAK VORTICITY MAXIMA MOVING AROUND THE NORTHERN PERIPHERY OF
THE MID LEVEL RIDGE AND CROSSING WESTERN NY THIS AFTERNOON. THERE
WILL LIKELY BE A MESOSCALE CONVERGENCE ZONE JUST INLAND FROM LAKE
ERIE...SEPARATING ENHANCED FLOW CHANNELING DOWN THE LAKE AND WEAKER
WINDS INLAND. SURFACE TEMPERATURES WILL WARM INTO THE LOWER TO MID
80S WITH DEWPOINTS IN THE UPPER 60S. THIS WILL YIELD AROUND 1500J/KG
OF SBCAPE...ALTHOUGH WARM MID LEVELS MAY KEEP SOME CINH IN THE
PROFILE. THE BEST CHANCE OF ANY DEEP MOIST CONVECTION WILL BE ALONG
THE AFOREMENTIONED BOUNDARY...WHICH MAY ORGANIZE LOW LEVEL MASS
CONVERGENCE ENOUGH TO BREACH THE MID LEVEL CAP. WITH THIS IN MIND
HAVE DRAWN A CORRIDOR OF CHANCE POPS FOR THE AFTERNOON FROM
CHAUTAUQUA COUNTY NORTHEAST TO THE ROCHESTER AREA. THIS ALSO
INCLUDES THE SOUTHEAST HALF OF THE BUFFALO AREA...WITH A SSW FLOW
OFF THE LAKE LIKELY KEEPING NORTHERN PORTIONS OF THE NIAGARA
FRONTIER DRY. FARTHER EAST THE NORTH COUNTRY SHOULD STAY DRY WITH
LESS INSTABILITY AND NO TRIGGER.

IT WILL BE A WARM AND MUGGY DAY WITH HIGHS IN THE MID 80S ACROSS THE
LOWER ELEVATIONS OF WESTERN NY...AND AROUND 80 ACROSS HIGHER TERRAIN.

THIS EVENING ANY DIURNALLY DRIVEN SHOWERS AND STORMS WHICH DO
DEVELOP SHOULD WEAKEN AND DISSIPATE BY EARLY TO MID EVENING. THIS
SHOULD LEAVE THE AREA DRY AND PARTLY CLOUDY BEFORE THE NEXT SYSTEM
APPROACHES AFTER MIDNIGHT. MID LEVEL HEIGHT FALLS WILL APPROACH
WESTERN NY LATE...WITH A LEAD CONVECTIVELY AUGMENTED SHORTWAVE
ARRIVING SHORTLY AFTER 12Z TUE. DPVA AHEAD OF THIS FEATURE WILL
PROVIDE INCREASING LARGE SCALE ASCENT LATE TONIGHT...AND UPPER LEVEL
DIVERGENCE WILL INCREASE AS THE RIGHT ENTRANCE REGION OF A 90+ KNOT
UPPER LEVEL JET APPROACHES. THIS WILL ALL PRODUCE INCREASING CHANCES
OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS LATE TONIGHT.

HIGH DEWPOINTS AND AN INCREASING SSW GRADIENT WILL KEEP TEMPERATURES
WARM AND MUGGY OVERNIGHT...WITH LOWS AROUND 70 ON THE LAKE PLAINS
AND MID 60S ACROSS THE HIGHER TERRAIN.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A COLD FRONT IS STILL ON TRACK TO CROSS THE FORECAST AREA DURING THE
DAY ON TUESDAY. SHOWERS AND THUNDERSTORMS ARE LIKELY OUT AHEAD OF
AND ALONG THE BOUNDARY. EXPECT PRECIPITATION TO MOVE INTO WESTERN
NEW YORK TUESDAY MORNING...REACHING NORTHCENTRAL NEW YORK BY EARLY
AFTERNOON...THEN TAPER OFF FROM WEST TO EAST THROUGH EARLY EVENING.
THUNDERSTORM POTENTIAL REMAINS HIGH WITH FORECAST SBCAPES GENERALLY
RUNNING BETWEEN 1000-1500 J/KG COMBINED WITH LIFTED INDEX VALUES
AROUND -3C...OR EVEN A BIT LOWER BY EARLY AFTERNOON. 0-6KM BULK
SHEAR WILL BE AROUND 30-35KT...WHICH IS NOT QUITE AS HIGH AS I`D
LIKE TO SEE FOR BETTER SEVERE POTENTIAL. KEY FACTOR WILL BE THE
AMOUNT OF SURFACE HEATING THAT TAKES PLACE BEFORE FROPA...I.E. WILL
CLOUD COVER MOVE IN TOO EARLY AND LIMIT HEATING...AND THUS THE
AMOUNT OF INSTABILITY. CENTRAL AND NORTHERN NEW YORK HAVE THE BEST
SHOT AT SEEING THE MOST SUNSHINE OUT AHEAD OF THE FRONT...SO THIS
MAY BE THE MOST FAVORED AREA FOR STRONGER STORMS. IN ADDITION...TALL
SKINNY CAPE PROFILES SHOWN IN BUFKIT AND HIGH PRECIPITABLE WATER
VALUES OF 1.7"-1.9" OUT AHEAD OF THE BOUNDARY OFFERS THE RISK FOR
HEAVY DOWNPOURS WITH ANY THUNDERSTORM. ALL THESE FACTORS TAKEN INTO
CONSIDERATION...IT APPEARS THERE MAY SOME STRONG STORMS...WITH A FEW
STORMS POSSIBLY REACHING SEVERE LIMITS. MAIN THREATS APPEAR TO BE
GUSTY WINDS ASSOCIATED WITH ANY BOWING LINE SEGMENTS...AND TO A
LESSER EXTENT MARGINALLY SEVERE HAIL. IT WILL BE ANOTHER WARM DAY
WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S.

THE COLD FRONT WILL SLIDE SOUTH AND EAST OF THE FORECAST AREA
TUESDAY NIGHT...TAKING THE SHOWERS AND STORMS WITH IT. ALTHOUGH A
FEW SHOWERS WILL STILL BE POSSIBLE DURING THE EVENING ACROSS EASTERN
AREAS...BUT EVEN HERE THINGS WILL DRY OUT LATER TUESDAY NIGHT AS
SURFACE HIGH PRESSURE LOCATED ACROSS THE OHIO VALLEY STARTS TO BUILD
EAST ACROSS THE REGION. LOWS WILL BE GENERALLY IN THE UPPER 50S TO
LOWER 60S.

LOW AMPLITUDE BROAD UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE
WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND WEDNESDAY NIGHT WITH A
DRIER MORE COMFORTABLE AIRMASS...BUT NOT MUCH COOLER TEMPERATURE
WISE. EXPECT MOSTLY SUNNY SKIES THROUGHOUT THE REGION AND HIGH TEMPS
IN THE MID TO UPPER 70S...FOLLOWED BY A CLEAR NIGHT WITH LOWS
DROPPING BACK INTO THE 50S.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL REMAIN ACROSS THE
REGION ON THURSDAY. HIGH PRESSURE WILL THEN SLIDE OFF THE NEW
ENGLAND COAST BY FRIDAY. THIS WILL CONTINUE MAINLY DRY CONDITIONS ON
THURSDAY...THEN THE NEXT FRONTAL SYSTEM APPROACHES FOR LATE IN THE
WEEK AND EARLY WEEKEND. TEMPERATURES WILL BE A BIT ABOVE SEASONAL
NORMALS THROUGH THE END OF THE WORK WEEK WITH HIGHS IN THE UPPER 70S
TO LOW 80S AND LOWS IN THE LOWER 60S...THEN SETTLE A BIT CLOSER TO
NORMAL WITH HIGHS IN THE LOWER TO MID 70S AND LOWS IN THE MID 50S
DURING THE WEEKEND.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
FOG AND STRATUS WILL BECOME MORE WIDESPREAD ACROSS THE REGION
OVERNIGHT INTO EARLY MONDAY MORNING. EXTENSIVE LOW LEVEL MOISTURE
TRAPPED BENEATH A WEAK SUBSIDENCE INVERSION COUPLED WITH NOCTURNAL
COOLING WILL PROVIDE AN ENVIRONMENT FAVORABLE FOR BOTH LOW STRATUS
AND FOG. IFR CIGS ARE ALREADY WIDESPREAD ACROSS THE HIGHER TERRAIN
OF THE SOUTHERN TIER...AND EXPECT THIS TO EXPAND NORTH AND EAST
THROUGH THE REST OF THE NIGHT. THE LOWER ELEVATIONS FROM KBUF AND
KIAG TO KROC SHOULD SEE A FEW HOURS OF IFR CIGS BETWEEN 09Z-14Z.
EAST OF LAKE ONTARIO MVFR CIGS WILL PERSIST THROUGH 09Z THEN MAY
PARTIALLY CLEAR LATE TONIGHT.

AS FAR AS FOG GOES...EXPECT LOWER ELEVATIONS TO PRIMARILY
SEE JUST LIGHT BR WITH A LITTLE TOO MUCH MIXING IN THE BOUNDARY
LAYER FOR MORE SIGNIFICANT FOG. THE HIGHER TERRAIN OF THE SOUTHERN
TIER AND FINGER LAKES MAY SEE MORE WIDESPREAD IFR FOG WHERE THE LOW
STRATUS INTERSECTS THE HILLTOPS.

THE FOG AND LOW STRATUS WILL BURN OFF BY MID TO LATE MORNING MONDAY
WITH CONDITIONS IMPROVING TO MAINLY VFR BY MIDDAY. A FEW WIDELY
SCATTERED SHOWERS AND STORMS MAY DEVELOP DURING THE AFTERNOON AND
EVENING MAINLY ACROSS WESTERN NY WITH LOCAL MVFR/IFR IN ANY HEAVIER
SHOWERS...BUT THE MAJORITY OF THE AREA WILL REMAIN VFR.

OUTLOOK...
TUESDAY...SHOWERS AND THUNDERSTORMS LIKELY WITH ASSOCIATED BRIEF
MVFR/IFR. SOME STORMS MAY BE STRONG.
WEDNESDAY AND THURSDAY...VFR.
FRIDAY...MAINLY VFR. A CHANCE OF SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
A WEAK PRESSURE GRADIENT WILL KEEP WINDS LIGHT ACROSS THE LOWER
LAKES TODAY WITH GOOD BOATING CONDITIONS ON BOTH LAKES. A COLD FRONT
WILL MOVE INTO THE CENTRAL LAKES TONIGHT THEN CROSS THE LOWER LAKES
ON TUESDAY. SOUTHWEST WINDS WILL INCREASE IN ADVANCE OF THIS FRONT
LATER TONIGHT...ESPECIALLY ON LAKE ERIE WHERE A BRIEF PERIOD OF
MODERATE WINDS WILL PRODUCE CHOPPY CONDITIONS LATE TONIGHT INTO
TUESDAY MORNING. FOR NOW HAVE HELD WINDS AND WAVES JUST SHY OF SMALL
CRAFT ADVISORY CRITERIA.

THE COLD FRONT WILL PRODUCE SCATTERED TO NUMEROUS THUNDERSTORMS ON
TUESDAY...A FEW OF WHICH MAY CONTAIN GUSTY WINDS. HIGH PRESSURE WILL
THEN BUILD INTO THE LOWER LAKES BEHIND THE COLD FRONT WITH A RETURN
TO LIGHT WINDS WEDNESDAY AND THURSDAY.

&&

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

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...JM
LONG TERM...JM/WCH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK







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