Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 291737
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
137 PM EDT SAT AUG 29 2015

.SYNOPSIS...
A WEAK MID LEVEL DISTURBANCE MAY BRING A FEW SPRINKLES OR LIGHT
SHOWERS TO THE REGION TONIGHT AND SUNDAY WITH THE GREATEST CHANCES
ACROSS THE SOUTHERN TIER. HIGH PRESSURE WILL THEN RETURN FOR THE
FIRST HALF OF NEXT WEEK WITH TEMPERATURES RUNNING ABOVE NORMAL FOR
THE END OF SUMMER.

&&

.NEAR TERM /THROUGH TONIGHT/...
SATELLITE IMAGERY SHOWS EXTENSIVE MID/HIGH LEVEL CLOUDINESS ACROSS
THE CENTRAL GREAT LAKES THIS AFTERNOON...AND THIS WILL GRADUALLY
SPREAD EAST INTO OUR REGION THROUGH THE REST OF THE AFTERNOON AND
EVENING IN RESPONSE TO THE EASTWARD PROGRESS OF DPVA AHEAD OF A MID
LEVEL TROUGH OVER THE CENTRAL LAKES AND INCREASING MID/UPPER LEVEL
WAA AND ISENTROPIC UPGLIDE AHEAD OF A WEAK WARM FRONTAL SEGMENT OVER
NORTHERN ILLINOIS/INDIANA. THROUGH THE REST OF THE AFTERNOON EXPECT
A MIX OF SUN AND CLOUDS ACROSS MUCH OF THE REGION WITH THE THICKER
AND MORE PERSISTENT CLOUD COVER TENDING TO STAY NORTH OF THE
US/CANADIAN BORDER.

TONIGHT THE WEAK MID LEVEL TROUGH UPSTREAM ACROSS THE CENTRAL LAKES
WILL SLOWLY DRIFT EAST TOWARDS OUR REGION AND WEAKEN FURTHER. A FEW
EMBEDDED WEAK VORTICITY MAXIMA WILL PRODUCE A FEW PERIODS OF WEAK
DPVA...AND AN ASSOCIATED MODEST 30 KNOT LOW LEVEL JET WILL AID IN
INCREASING MID LEVEL WAA/ISENTROPIC UPGLIDE OVERNIGHT. FORCING AND
MOISTURE CONVERGENCE APPEAR TO MAXIMIZE ACROSS THE WESTERN SOUTHERN
TIER FROM LATE EVENING ON ALONG THE PATH OF A WEAK CONVECTIVELY
AUGMENTED VORTICITY CENTER...AND THIS IS WHERE THE LATEST HIGH
RESOLUTION GUIDANCE SUCH AS THE NAM AND CANADIAN GEM POINT TOWARDS
THE GREATEST SHOWER CHANCES. FARTHER NORTH FROM THE NIAGARA FRONTIER
EAST ACROSS ROCHESTER AND THE NORTHERN FINGER LAKES...THE NAM
APPEARS OVERDONE WITH QPF. THE WEAK WARM ADVECTION AND DPVA REGIME
MAY SUPPORT A FEW SCATTERED SPRINKLES FALLING OUT OF A MID LEVEL
DECK OVERNIGHT...BUT CHANCES OF MEASURABLE RAIN STAY QUITE LOW.

OTHERWISE EXPECT PLENTY OF MID LEVEL CLOUD COVER OVERNIGHT. THE
ADDED CLOUD COVER SHOULD PREVENT FOG FROM FORMING IN THE SOUTHERN
TIER VALLEYS...AND ALSO HELP TO KEEP OVERNIGHT LOWS ON THE MILD
SIDE. EXPECT LOW TO MID 60S ON THE LAKE PLAINS AND UPPER 50S ACROSS
THE INTERIOR SOUTHERN TIER AND TUG HILL REGION.

ON SUNDAY ANY SCATTERED SPRINKLES OR LIGHT SHOWERS ACROSS THE
SOUTHERN TIER AND FINGER LAKES WILL END EARLY AS THE WEAK
CONVECTIVELY AUGMENTED VORTICITY CENTER MOVES EAST AND DAMPENS OUT.
DURING THE AFTERNOON THE REMNANTS OF THE WEAK MID LEVEL TROUGH WILL
DRIFT SOUTHEAST ACROSS THE AREA. SOME MODEST INCREASE IN BOUNDARY
LAYER MOISTURE AND DAYTIME HEATING WILL CONTRIBUTE TO WEAK TO
MODERATE INSTABILITY...WITH MODEL POINT SOUNDINGS SUGGESTING AROUND
1000J/KG OF SBCAPE BY MID AFTERNOON. THE COMBINATION OF INSTABILITY
AND WEAK ASCENT...ALONG WITH INLAND ADVANCING LAKE BREEZE BOUNDARIES
MAY BE ENOUGH TO PRODUCE A FEW WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS FROM SOUTHERN ERIE AND WYOMING COUNTIES SOUTH AND EAST
INTO THE SOUTHERN TIER. FOR THE REST OF THE AREA LESSER MOISTURE AND
FORCING SHOULD ALLOW DRY CONDITIONS.

OTHERWISE EXPECT A GOOD AMOUNT OF CLOUD COVER TO THE SOUTH OF THE
THRUWAY FROM THE DEPARTING MORNING WAVE AND THEN AFTERNOON
INSTABILITY. THERE WILL BE A LITTLE MORE SUN IN AREAS CLOSER TO THE
CANADIAN BORDER WITH DRIER AIR BEGINNING TO PUSH SOUTH. 850MB TEMPS
AROUND 14C SHOULD SUPPORT HIGHS IN THE LOWER 80S AT LOWER ELEVATIONS
WITH MID TO UPPER 70S ACROSS HIGHER TERRAIN AND ALONG THE LAKESHORES
WHERE WEAK SYNOPTIC FLOW WILL ALLOW LOCAL LAKE BREEZE CIRCULATIONS
TO DEVELOP BY AFTERNOON.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
THE SYNOPTIC UPPER LEVEL PATTERN ACROSS THE CONUS ON SUNDAY WILL
FEATURE AN EXPANSIVE RIDGE EXTENDING NORTH ACROSS THE FOUR CORNERS
AND PLAINS STATES. FURTHER EAST...BROAD/WEAK TROUGHING AND AN
ASSOCIATED EMBEDDED WEAK DISTURBANCE WILL BE SHIFTING ACROSS THE
EASTERN GREAT LAKES. SURFACE HIGH PRESSURE WILL BE CENTERED FROM THE
CAROLINAS INTO THE MID-ATLANTIC STATES. THE POSITION OF THE SURFACE
HIGH WILL CONTINUE TO DIRECT WARM AND MOIST AIR NORTH TO WESTERN AND
CENTRAL NEW YORK. THIS IS WHAT WILL BRING TEMPERATURES AND HUMIDITY
LEVEL BACK ABOVE NORMAL FOR LATE AUGUST AND THE START OF SEPTEMBER.

THE PREVIOUSLY MENTIONED WEAK MID LEVEL DISTURBANCE CROSSING OUR
REGION SUNDAY AFTERNOON LOOKS TO STILL PROVIDE MINIMAL LIFT TO
CONTINUE WITH A CHANCE FOR SHOWERS AND SLIGHT CHANCE FOR A
THUNDERSTORM MAINLY ACROSS THE SOUTHERN TIER COUNTIES. THIS IS WHERE
MODELS ARE SHOWING THE BEST... ALBEIT WEAK...INSTABILITY AND CLOSER
TO DEEPER MOISTURE PROFILES SUNDAY AFTERNOON AS THE DISTURBANCE
MOVES OVERHEAD. SUNDAY NIGHT THROUGH MONDAY SURFACE AND UPPER LEVEL
RIDGING WILL EXPAND ACROSS THE GREAT LAKES. THIS WILL KEEP A DRY
FORECAST INTO NEXT WEEK WITH TEMPERATURES REMAINING ABOVE NORMAL.
HIGH TEMPERATURES WILL RUN IN THE UPPER 70S TO LOW 80S WITH VERY
MILD AND HUMID OVERNIGHT LOWS ONLY SLIPPING BACK INTO THE 60S.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
UPPER LEVEL RIDGING WILL BE THE DOMINANT WEATHER FEATURE ACROSS THE
EASTERN HALF OF THE NATION THROUGH MUCH OF NEXT WEEK. THIS WILL
TRANSLATE INTO A PERIOD OF LARGELY DRY WEATHER AND MIDSUMMER-LIKE
WARMTH AND HUMIDITY FOR OUR REGION...WITH DAYTIME HIGHS AVERAGING IN
THE MID 80S...AND NIGHTLY LOWS MOSTLY RANGING IN THE LOWER TO MID
60S. LATER IN THE WEEK...MODELS ARE SUGGESTING SOME BREAKING DOWN OF
THE RIDGE BY A WEAK SHORTWAVE MOVING THROUGH THE UPPER FLOW AROUND
THURSDAY. THERE ALSO MAY BE A DISSIPATING COLD FRONT PASSING SOUTH
ACROSS THE GREAT LAKES THAT COULD TRIGGER SOME PRECIPITATION. HAVE
GONE WITH A SLIGHT CHANCE FOR THUNDERSTORMS GIVEN THE WARM AND HUMID
AIRMASS IN PLACE THURSDAY AND THURSDAY NIGHT UNTIL A MORE CLEAR
PICTURE CAN BE SEEN IN GUIDANCE. NO REMNANTS FROM TROPICAL CYCLONE
ERIKA ARE EXPECTED TO IMPACT OUR FORECAST AREA AT THIS TIME.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A WEAK WARM FRONT AND MID LEVEL TROUGH OVER THE CENTRAL GREAT LAKES
WILL MOVE EAST TOWARDS THE AREA LATER TODAY THEN CROSS THE LOWER
LAKES TONIGHT. WEAK WARM ADVECTION IN THE MID AND UPPER LEVELS AHEAD
OF THESE FEATURES WILL BRING A SLOW INCREASE IN MID/HIGH LEVEL CLOUD
COVER THIS AFTERNOON AND EVENING FROM WEST TO EAST. THERE MAY BE
JUST ENOUGH ASCENT TO GENERATE A FEW SPRINKLES TONIGHT WITH A LITTLE
BETTER CHANCE OF SCATTERED SHOWERS ACROSS THE SOUTHERN TIER.
CIGS/VSBY WILL REMAIN VFR AS THE LOW LEVELS REMAIN UNSATURATED.

ON SUNDAY ANY SPRINKLES OR LIGHT SHOWERS ACROSS THE SOUTHERN TIER
WILL END BY MID MORNING. THE REMAINS OF THE MID LEVEL TROUGH WILL
DRIFT ACROSS THE AREA DURING THE AFTERNOON. THIS WILL COMBINE WITH
DAYTIME HEATING TO PRODUCE A FEW WIDELY SCATTERED SHOWERS AND
PERHAPS A THUNDERSTORM MAINLY ACROSS THE HIGHER TERRAIN OF THE
WESTERN SOUTHERN TIER AND WESTERN FINGER LAKES. AGAIN CIGS/VSBY WILL
REMAIN VFR...ALTHOUGH IF A THUNDERSTORM IS ABLE TO DEVELOP DURING
THE AFTERNOON IT WOULD PRODUCE BRIEF/LOCAL MVFR TO IFR CONDITIONS.

OUTLOOK...
MONDAY THROUGH THURSDAY...MAINLY VFR.

&&

.MARINE...
WINDS AND WAVES WILL REMAIN LIGHT THROUGH THE REMAINDER OF THE
WEEKEND AND INTO THE FIRST HALF OF NEXT WEEK AS SURFACE HIGH
PRESSURE REMAINS ANCHORED ACROSS THE NORTHEAST QUARTER OF THE
NATION. WINDS WILL GENERALLY REMAIN 12 KNOTS OR LESS WITH WAVES 2
FEET OR LESS.

&&

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

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...SMITH
LONG TERM...JJR/SMITH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK



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