Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 211425
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1025 AM EDT THU MAY 21 2015

.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE WESTERN AND NORTH CENTRAL NEW YORK
WITH FAIR WEATHER AND COOLER THAN AVERAGE TEMPERATURES THROUGH
SATURDAY...BEFORE WARMER WEATHER RETURNS FOR THE REST OF THE
MEMORIAL DAY WEEKEND...ALONG WITH THE CHANCE FOR SOME SHOWERS AND
THUNDERSTORMS BY NEXT WEEK MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THIS LATE MORNING SKIES ARE CLEARING
AS THE FIRST...AND WEAK MID LEVEL SHORTWAVE AND SOUTHERN SURFACE
LOW ADVANCES EASTWARD. SUNSHINE WILL BE MOST ABUNDANT ACROSS
NORTHERN PORTIONS OF THE CWA...WHILE NEAR THE STATE LINE CLOUDS
WILL REMAIN THROUGH A GOOD PORTIONS OF THE DAY. A SPRINKLE IS
POSSIBLE NEAR THE SOUTHERN TIER LATER THIS AFTERNOON AND EVENING
AS A SECOND AND MORE POTENT SHORTWAVE PASSES ACROSS PENNSYLVANIA.

FOLLOWING THE PASSAGE OF THIS SHORTWAVE...DRY WEATHER WILL BE COMMON
AREAWIDE FOR THE REMAINDER OF THE EVENING HOURS...BEFORE A WEAK COLD
FRONTAL BOUNDARY SLOWLY EASES INTO THE REGION OVERNIGHT. WITH THIS
FEATURE LOOKING TO ACCOMPANIED BY A LIMITED INCREASE IN MOISTURE AND
ONLY MODEST MID-LEVEL SUPPORT...EXPECT IT TO PRIMARILY BRING AN
INCREASE IN CLOUD COVER AND PERHAPS A FEW ADDITIONAL SPOTTY SPRINKLES
OR LIGHT SHOWERS...WITH THE MAJORITY OF THE REGION GENERALLY EXPECTED
TO REMAIN DRY THROUGH THE NIGHT.

WITH RESPECT TO TEMPERATURES...850 MB TEMPS WILL RECOVER TO BETWEEN
+3C AND +4C TODAY...AND THIS SHOULD TRANSLATE INTO FAIRLY WIDESPREAD
HIGHS IN THE LOWER TO MID 60S AWAY FROM ANY LAKE INFLUENCES...WITH
THE WARMEST READINGS EXTENDING FROM THE MIDDLE AND LOWER PORTIONS OF
THE GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES. THE SOUTHERN TIER
WILL BE A LITTLE COOLER DUE TO THE GREATER AMOUNTS OF CLOUD COVER
EXPECTED THERE...WITH THE COOLEST READINGS OF ALL EXPECTED ALONG THE
LAKE ONTARIO SHORELINE FROM WAYNE COUNTY TO JEFFERSON COUNTY...WHERE
AN ONSHORE FLOW OFF THE COLDER WATERS OF LAKE ONTARIO SHOULD KEEP
TEMPS FROM GETTING MUCH ABOVE THE LOWER 50S. LOWS TONIGHT SHOULD
THEN RANGE THROUGH THE LOWER HALF OF THE 40S...WITH ENOUGH CLOUD
COVER AND WIND EXPECTED TO BE PRESENT TO PRECLUDE ANY REAL THREAT OF
FROST.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
THIS WILL BE A PERIOD OF GENERALLY BENIGN WEATHER ACROSS WESTERN
AND NORTH CENTRAL NEW YORK...AS A COOL AND DRY CONTINENTAL AIRMASS
FROM CENTRAL CANADA WILL BE IN PLACE. WHILE TEMPERATURES WILL
REMAIN BELOW NORMAL...THERE WILL BE A NOTICEABLE DAY TO DAY
WARMING TREND AS A LONGWAVE TROUGH OVER EASTERN CANADA WILL
GRADUALLY PUSH EAST AND ALLOW RIDGING TO BUILD OVER THE MID WEST
AND LOWER GREAT LAKES. THE DETAILS...

A COLD FRONT WILL DROP SOUTH ACROSS OUR FORECAST AREA FRIDAY
MORNING. THIS FEATURE WILL NOT HAVE A LOT OF MOISTURE TO WORK
WITH...SO ANY SHOWER ACTIVITY WILL BE SPOTTY IN NATURE WITH
NEGLIGIBLE QPF. WHILE THE VARIOUS GUIDANCE PACKAGES AGREE ON THE
PASSAGE OF A VIGOROUS POST FRONTAL SHORTWAVE DURING THE
AFTERNOON...THERE IS LITTLE CONSENSUS ON THE AMOUNT OF LOW LEVEL
MOISTURE. WILL LEAN ON A MIX OF OUR CONTINUITY AND THE
SREF...WHICH FAVOR A DRY IDEA FOR THE AFTERNOON. SPEAKING OF
WHICH...H85 TEMPS IN THE WAKE OF THE COLD FRONT WILL DROP TO
BETWEEN ZERO AND -2C DURING THE SECOND HALF OF THE DAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE MID AND UPPER 50S...WHICH WILL BE
AT LEAST 10 DEG F BELOW NORMAL.

SPRAWLING HIGH PRESSURE WILL SETTLE ACROSS THE UPPER OHIO VALLEY
FRIDAY NIGHT. THIS WILL SET THE STAGE FOR A VERY CHILLY NIGHT
ACROSS OUR REGION...WITH CLEAR SKIES AND LIGHT WINDS ENCOURAGING
GOOD RADIATIONAL COOLING...WHICH IN TURN WILL LEAD TO AREAS OF
FROST. WHILE JUST ABOUT ALL AREAS AREA FROM THE IMMEDIATE LAKE
SHORES COULD EXPERIENCE AT LEAST PATCHY FROST BY SATURDAY
MORNING...THERE IS THE LIKELIHOOD OF FREEZING TEMPERATURES (UPPER
20S-LOWER 30S) ACROSS A LARGE PORTION OF THE WESTERN SOUTHERN TIER
AND PARTS OF THE NORTH COUNTRY. HAVE THUS ISSUED A FREEZE WATCH
FOR WYOMING...CATTARAUGUS AND ALLEGANY COUNTIES FOR LATE FRIDAY
NIGHT. CONFIDENCE IS NOT QUITE AS HIGH FOR LEWIS COUNTY...SO WILL
ALLOW DAYSHIFT TO RE-EXAMINE. FROST ADVISORIES WILL LIKELY BE
ISSUED FOR THE REMAINING COUNTIES IN A LATER PACKAGE WHILE FROST
WILL CONTINUE TO BE MENTIONED IN THE FORECAST.

THE SURFACE HIGH WILL DRIFT ACROSS THE MID ATLANTIC STATES ON
SATURDAY. THIS WILL SET UP A WARM ADVECTIVE PATTERN OVER THE LOWER
GREAT LAKES...WITH H85 TEMPS OVER OUR REGION MODIFYING TO BETWEEN
+4 AND 6C BY LATE AFTERNOON. GIVEN FULL SUNSHINE...THIS WILL
GENERATE AFTERNOON MAX TEMPS IN THE MID 60S FOR MOST AREAS.

SATURDAY NIGHT WILL NOT BE NEARLY AS CHILLY AS THE PREVIOUS
NIGHT. A MILDER FLOW OF AIR BETWEEN A COLD FRONT DROPPING SOUTH
FROM QUEBEC AND HIGH PRESSURE EXITING OFF THE MID ATLANTIC COAST
WILL HELP TO KEEP MIN TEMPS BETWEEN 45 AND 50 FOR MOST AREAS.

WEAK WARM ADVECTION WILL CONTINUE ACROSS OUR FORECAST AREA ON
SUNDAY AS MID LEVEL RIDGING WILL BUILD ACROSS THE MID WEST. WHILE
WE WILL LIKELY EXPERIENCE AN INCREASE IN MID AND HIGH LEVEL CLOUD
COVER DURING THE COURSE OF THE DAY...OUR TREND OF CLIMBING MAX
TEMPS WILL CONTINUE AS HIGHS ARE FORECAST TO BE IN THE LOW TO MID
70S.

A WARM FRONT DEVELOPING OVER THE UPPER OHIO VALLEY SUNDAY EVENING
WILL PUSH NORTHEAST TOWARDS OUR AREA DURING THE COURSE OF SUNDAY
NIGHT. THIS WILL OFFER THE OPPORTUNITY FOR SOME SHOWERS OVER
SOUTHWESTERN NEW YORK STATE LATE SUNDAY NIGHT...WHILE THE REST OF
THE REGION WILL BECOME CLOUDY WITH OVERNIGHT LOWS FORECAST TO BE
IN THE LOW TO MID 50S...RIGHT WHERE THEY SHOULD BE FOR THIS TIME
OF YEAR.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
WHILE THERE ARE THE TYPICAL DIFFERENCES BETWEEN THE MEDIUM RANGE
DETERMINISTIC MODELS...THERE IS FAIRLY STRONG CONSENSUS BETWEEN
THE ENSEMBLES THAT RIDGING PARKED OVER THE SOUTHEASTERN STATES
WILL SUPPORT RELATIVELY WARM AND MORE HUMID CONDITIONS OVER OUR
REGION THROUGHOUT THIS PERIOD. IT IS ALSO EXPECTED TO BE MORE
UNSETTLED THAN THE PERIOD LEADING UP TO THIS AS WELL...AS THE
INCREASINGLY UNSTABLE AIRMASS WILL INTERACT WITH SUBTLE LAKE
BREEZE BOUNDARIES AND INDISCRIMINATE SHORTWAVES RIDING UP ALONG
THE WESTERN PERIPHERY OF THE AFOREMENTIONED MID LEVEL RIDGE TO
PRODUCE DAILY SCATTERED SHOWERS AND THUNDERSTORMS.

ANY PRECIPITATION AT THIS EARLY STAGE OF THE GROWING SEASON WOULD
CERTAINLY BE WELCOMED. MOST AREAS ARE RUNNING ONE TO TWO INCHES
BELOW NORMAL WITH RAINFALL THIS MONTH...WITH SOME LOCATIONS
AVERAGING MORE THAN FOUR INCHES BELOW NORMAL FOR THE CALENDAR
YEAR.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
EXPECT VFR CONDITIONS TO CONTINUE TO PREVAIL THROUGH THE TAF
PERIOD. FAIRLY WIDESPREAD MID AND HIGH CLOUDS ASSOCIATED WITH A
WEAK WAVE OF LOW PRESSURE AND AN ATTENDANT UPPER LEVEL JET STREAK
PASSING ACROSS THE OHIO VALLEY WILL TEND TO THIN OUT SOME FROM
NORTH TO SOUTH TODAY AND THIS EVENING FOLLOWING THE PASSAGE OF
THESE FEATURES...BEFORE VFR CLOUD COVER INCREASES AGAIN OVERNIGHT
TONIGHT IN ASSOCIATION WITH AN APPROACHING COLD FRONTAL BOUNDARY.
WHILE THIS LATTER FEATURE COULD TOUCH OFF A FEW SPOTTY SPRINKLES
OR LIGHT SHOWERS LATE TONIGHT... THESE ARE NOT EXPECTED TO PRODUCE
ANY RESTRICTIONS IN FLIGHT CONDITIONS.

OUTLOOK...
FRIDAY THROUGH SUNDAY...VFR.
MONDAY...VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS/ATTENDANT
MVFR.

&&

.MARINE...
SAVE FOR THE PASSAGE OF A WEAK COLD FRONT LATER TONIGHT AND EARLY
FRIDAY...HIGH PRESSURE WILL REMAIN DOMINANT ACROSS THE LOWER GREAT
LAKES THROUGH THE UPCOMING WEEKEND. THIS SHOULD RESULT IN A
PROLONGED PERIOD OF SUB-ADVISORY-LEVEL WINDS AND WAVES...BOTH OF
WHICH WILL PEAK TONIGHT AND EARLY FRIDAY IN CONJUNCTION WITH THE
APPROACH AND PASSAGE OF THE AFOREMENTIONED COLD FRONT.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING
     FOR NYZ012-020-021.
MARINE...NONE.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR/THOMAS
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR


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