Area Forecast Discussion
Issued by NWS Buffalo, NY

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290
FXUS61 KBUF 060744
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
344 AM EDT FRI MAY 6 2016

.SYNOPSIS...
AN UPPER LEVEL LOW ALONG THE CAROLINA COAST WILL DRIFT NORTHWARD
INTO THE MID ATLANTIC STATES TODAY...BEFORE WEAKENING AND SLIDING
OFF THE EASTERN SEABOARD ON SATURDAY. THIS SYSTEM WILL BRING A
CHANCE FOR SOME ADDITIONAL SHOWERS BACK INTO THE REGION FOR A TIME
LATE TODAY AND TONIGHT...BEFORE DRIER WEATHER RETURNS OVERNIGHT
AND FOR MUCH OF SATURDAY. MEANWHILE...TEMPERATURES WILL AVERAGE
A LITTLE ABOVE NORMAL THROUGH SATURDAY. A WAVY COLD FRONT WILL
THEN CROSS THE REGION SATURDAY NIGHT ALONG WITH ANOTHER ROUND OF
MORE WIDESPREAD SHOWERS AND POSSIBLE THUNDERSTORMS...WITH COOLER
AIR THEN FOLLOWING FOR SUNDAY AND MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
DURING THIS PERIOD...AN UPPER LEVEL LOW CURRENTLY CENTERED
ALONG THE CAROLINA COAST WILL MEANDER ITS WAY NORTHWARD INTO
THE DELMARVA REGION TODAY...WHERE IT WILL THEN LINGER IN PLACE
TONIGHT.

AS THE UPPER LOW DRIFTS TOWARD OUR REGION TODAY...IT WILL SPREAD
INCREASING AMOUNTS OF MOISTURE BACK INTO OUR REGION FROM THE
SOUTHEAST...AIDED BY A DEVELOPING LOW/MID LEVEL JET WITH ORIGINS
OVER THE WESTERN ATLANTIC. THIS WILL RESULT IN GRADUALLY
INCREASING/THICKENING CLOUDS ACROSS THE REGION FROM SOUTHEAST
TO NORTHWEST TODAY...WITH THE INCREASE IN CLOUDS MOST NOTICEABLE
ACROSS INTERIOR SECTIONS OF THE SOUTHERN TIER/FINGER LAKES AND
NORTH COUNTRY. FURTHER TO THE NORTHWEST ACROSS EXTREME FAR WESTERN
NEW YORK AND THE SAINT LAWRENCE VALLEY/ADJOINING PORTIONS OF THE
NORTH COUNTRY...THIS WILL BE MUCH LESS PRONOUNCED AND WILL ONLY
AMOUNT TO AN INCREASE IN SOME CIRRUS-LEVEL CLOUDINESS. AS FOR
PRECIP...MUCH OF THE DAY LOOKS TO BE DRY WITH ANY REAL SHOWER
POTENTIAL JUST REACHING OUR SOUTHEASTERN PERIPHERY LATER THIS
AFTERNOON...IN ASSOCIATION WITH THE LEADING EDGE OF BOTH THE
AFOREMENTIONED LOW LEVEL JET AND A MID LEVEL VORTICITY LOBE
ROTATING AROUND THE APPROACHING UPPER LOW.

WITH 850 MB TEMPS RECOVERING A BIT TO BETWEEN +4C AND +6C TODAY...
DAYTIME HIGHS SHOULD MOSTLY RANGE IN THE LOWER TO MID 60S...
WITH A FEW SPOTS IN THE SUNNIER PORTIONS OF THE NIAGARA FRONTIER
AND NORTH COUNTRY POSSIBLY REACHING THE UPPER 60S. AS HAS BEEN
THE CASE THE PAST SEVERAL DAYS...THE COOLEST OVERALL READINGS
WILL BE FOUND ALONG THE SOUTH SHORE OF LAKE ONTARIO...WHERE
AN ONSHORE FLOW WILL RESULT IN HIGHS STRUGGLING TO MAKE IT MUCH
ABOVE THE UPPER 40S AND LOWER 50S.

TONIGHT...CLOUD COVER WILL BECOME MORE WIDESPREAD ACROSS THE
REGION AS THE UPPER LOW MAKES ITS CLOSEST APPROACH...WITH SHOWER
CHANCES ALSO INCREASING FURTHER FOR A TIME THIS EVENING IN
CONJUNCTION WITH THE ABOVE REFERENCED LOW LEVEL JET AND VORT
LOBE. HAVE COVERED THIS WITH A FAIRLY SHARP GRADIENT IN POPS...
WITH SHOWER CHANCES RANGING FROM BELOW SLIGHT CHANCE ACROSS THE
NIAGARA RIVER AND EASTERN LAKE ERIE TO HIGHER-END LIKELY ACROSS
THE FINGER LAKES AND INTERIOR PORTIONS OF THE SOUTHERN TIER...
WHICH WILL LIE CLOSER TO THE UPPER LOW CENTER AND WILL BE SUBJECT
TO DEEPER OVERALL MOISTURE AND BETTER LARGE-SCALE FORCING.
TEMPORALLY SPEAKING...THE HIGHEST SHOWER POTENTIAL WILL COME
DURING THE FIRST PART OF THE EVENING...WITH THE SHOWER ACTIVITY
THEN LIKELY TO LARGELY TAPER OFF THROUGH THE BALANCE OF THE NIGHT
DUE TO BOTH THE LOSS OF HEATING AND DIMINISHING LARGER-SCALE
FORCING. OTHERWISE EXPECT A SEASONABLY MILD NIGHT FOR EARLY
MAY...WITH THE INCREASED CLOUD COVER AND SOMEWHAT HIGHER DEW
POINTS HELPING TO KEEP NIGHTTIME LOWS FROM FALLING BELOW THE MID
TO UPPER 40S ACROSS THE LOWER ELEVATIONS...AND THE LOWER TO MID
40S ACROSS THE HIGHER TERRAIN.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
THE WEEKEND WILL START OFF ON A PLEASANT NOTE...DESPITE A SOMEWHAT
CHAOTIC UPPER LEVEL PATTERN OVER THE NORTHEAST. A CLOSED LOW
ANCHORED IN THE VCNTY OF THE DELMARVA PENINSULA WILL FINALLY START
TO WEAKEN ON SATURDAY...WHILE A PAIR OF ROBUST SHORTWAVES WILL DIG
ACROSS THE UPPER MISSISSIPPI VALLEY. THIS WILL RESULT IN A PINCHED
SHORTWAVE RIDGE THAT WILL TRAVERSE THE LOWER GREAT LAKES DURING THE
COURSE OF THE DAY. THE RIDGE WILL INCLUDE A SWATH OF DRY AIR THAT
SHOULD ENABLE OUR FORECAST AREA TO ENJOY AT LEAST PARTIAL SUNSHINE.
THIS IN COMBINATION WITH H85 TEMPS OF 8 TO 10C WILL SUPPORT
AFTERNOON TEMPS IN THE LOWER 70S FOR MOST AREAS...WITH SOME MID 70S
POSSIBLE IN THE GENESEE AND SOUTHERN TIER VALLEYS. GIVEN THE WEAK
SYNOPTIC FLOW...LAKE BREEZES AND THEIR CORRESPONDING LOWER TEMPS ARE
NOT EXPECTED TO PENETRATE MORE THAN 5 MILES FROM SHORE.

SATURDAY IS NOT EXPECTED TO BE WITHOUT ISSUES THOUGH...AS CONDITIONS
OVER THE FAR WESTERN COUNTIES WILL DETERIORATE DURING THE MID AND
LATE AFTERNOON. MOISTURE WILL DEEPEN AHEAD OF AN APPROACHING COLD
FRONT DURING THE AFTERNOON...WITH SOME SHOWERS BECOMING POSSIBLE
TOWARDS DINNER TIME. THIS WILL MAINLY BE THE CASE WEST OF THE
GENESEE VALLEY.

THE AFOREMENTIONED MID LEVEL DISTURBANCES WILL CONTINUE TO DIG
SOUTHEAST ACROSS THE GREAT LAKES SATURDAY NIGHT...CARVING OUT AN
IMPRESSIVE LONGWAVE TROUGH OVER EASTERN CANADA AND PUSHING A COLD
FRONT THROUGH OUR REGION IN THE PROCESS. THE BULK OF THE SHOWERS
ASSOCIATED WITH THIS FRONTAL PASSAGE WILL TAKE PLACE BETWEEN 22 AND
03Z OVER THE FAR WESTERN COUNTIES AND 03Z TO 09Z FOR SITES EAST OF
LK ONTARIO. WILL MAINTAIN CAT POPS FOR SATURDAY NIGHT WITH QPF
GENERALLY UNDER A QUARTER INCH. RAINFALL COULD BE A BIT HIGHER FOR
THE EASTERN LAKE ONTARIO REGION. WHILE LAPSE RATES AND CORRESPONDING
INSTABILITY PARAMETERS WILL BE UNIMPRESSIVE...THE REGION WILL BE
FOUND UNDER THE JET EXIT REGION OF A 120KT H25 JET OVER LOWER
MICHIGAN AND OHIO.

IN THE WAKE OF THE FRONT ON SUNDAY...IT WILL BE BREEZY AND NOTABLY
COOLER. H85 TEMPS WILL AVERAGE -2 TO -4C...SO AFTERNOON TEMPERATURES
ARE NOT EXPECTED TO CLIMB OUT OF THE 50S. WHILE A BRIEF SHOWER
CANNOT BE RULED OUT WITHIN THE CHILLY CYCLONIC FLOW...SIGNIFICANT
DRYING THE MID LEVELS AND RIDGING IN THE LOW LEVELS SHOULD PRECLUDE
THE DEVELOPMENT OF ANY ORGANIZED/WIDESPREAD SHOWERS.

THE STAGE SHOULD THEN BE SET FOR A CHILLY NIGHT ACROSS THE REGION
SUNDAY NIGHT...AS LOW LEVEL RIDGING AND A FAIR AMOUNT OF DRY AIR
SHOULD ALLOW FOR DECENT RADIATIONAL COOLING. TEMPERATURES WELL AWAY
FROM THE LAKES WILL SETTLE INTO THE 30S...ALTHOUGH ANY PATCHY FROST
SHOULD BE CONFINED TO THE VALLEYS OF THE SRN TIER WHERE THE GROWING
SEASON HAS YET TO BEGIN.

FOR MONDAY...WEAK HIGH PRESSURE OVER THE LOWER GREAT LAKES WILL
PROVIDE THE REGION WITH SUN FILLED SKIES. WEAK WARM ADVECTION WITHIN
A DRY AIRMASS WILL HELP AFTERNOON TEMPERATURES CLIMB BACK INTO THE
60S FOR MOST AREAS...ALTHOUGH THESE READINGS WILL STILL BE SOME 5
DEG F BELOW NORMAL. REGARDLESS...MONDAY LOOKS LIKE A DELIGHTFUL DAY.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
THE EXAGGERATED AMPLIFICATION OF THE UPPER LEVEL FLOW THAT WAS
COMMON IN THE DAYS LEADING UP TO THIS LONG RANGE PERIOD WILL GIVE
WAY TO A BROAD...UNDULATING PACIFIC FLOW. WHILE THIS WILL RESULT IN
HIGHER TEMPERATURES ACROSS OUR REGION...MERCURY LEVELS SHOULD
AVERAGE WITHIN A FEW DEGREES OF NORMAL.

IN TERMS OF PRECIPITATION...THERE IS FAIRLY BROAD CONSENSUS AMONG
THE LONG RANGE ENSEMBLES THAT A STALLED FRONTAL BOUNDARY WILL LIE
JUST TO THE SOUTH OF OUR FORECAST AREA FOR TUESDAY AND WEDNESDAY.
THE DETAILS GET WASHED OUT (NO PUN INTENDED) AMONG THE ENSEMBLE
MEMBERS...BUT THERE WILL BE THE POTENTIAL FOR AT LEAST ONE WAVE TO
MAKE ITS WAY ALONG THE BOUNDARY TO ENHANCE SHOWER ACTIVITY ACROSS
THE WESTERN COUNTIES...AND IN PARTICULAR THE SOUTHERN TIER. WILL
BROAD BRUSH POPS TO ACCOUNT FOR THIS SCENARIO.

BY THE END OF THE PERIOD THOUGH...HIGH PRESSURE OVER JAMES BAY IS
FORECAST TO NOSE SOUTH ACROSS THE LOWER GREAT LAKES. THIS WOULD
FAVOR IMPROVING CONDITIONS AS WE WORK THROUGH WEDNESDAY NIGHT AND
THURSDAY.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AN UPPER LEVEL LOW INITIALLY CENTERED ALONG THE CAROLINA COAST
WILL MEANDER ITS WAY NORTHWARD INTO THE DELMARVA REGION TODAY...
WHERE IT WILL THEN LINGER THROUGH TONIGHT.

FOR THE BALANCE OF THE NIGHTTIME HOURS...DRY WEATHER AND VFR
CONDITIONS WILL CONTINUE TO PREVAIL ACROSS THE REGION...WITH
CLOUD COVER RANGING FROM JUST SOME PATCHY CIRRUS ACROSS THE TAF
SITES TO 5-10 KFT CIGS IN MID LEVEL CLOUDS ACROSS INTERIOR
PORTIONS OF THE GENESEE VALLEY AND FINGER LAKES.

GENERAL VFR CONDITIONS AND DRY WEATHER SHOULD THEN MANAGE TO
PERSIST THROUGH MUCH OF THE DAY TODAY...THOUGH CLOUDS WILL
GRADUALLY INCREASE/THICKEN FROM SOUTHEAST TO NORTHWEST AS
THE UPPER LOW DRAWS CLOSER. LATER ON IN THE AFTERNOON...A FEW
SHOWERS WITH REDUCTIONS TO MVFR VSBYS WILL BECOME POSSIBLE
ACROSS INTERIOR SECTIONS OF THE SOUTHERN TIER...FINGER LAKES...
AND NORTH COUNTRY.

TONIGHT...THE UPPER LOW WILL MAKE ITS CLOSEST APPROACH TO OUR
REGION DURING THE EVENING WHILE BRINGING A BETTER LIKELIHOOD OF
SOME SHOWERS TO INTERIOR PORTIONS OF THE SOUTHERN TIER/FINGER
LAKES/NORTH COUNTRY DURING THAT TIME...WITH THE SHOWER ACTIVITY
THEN GRADUALLY FADING OUT THROUGH THE BALANCE OF THE NIGHT.
WITHIN THE ABOVE REGION...THE SHOWERS WILL LIKELY BE ACCOMPANIED
BY SOME IFR TO MVFR CONDITIONS WHICH SHOULD THEN TEND TO REMAIN
IN PLACE FOR AT LEAST A PORTION OF THE NIGHT. ELSEWHERE...
CONDITIONS SHOULD PREDOMINANTLY REMAIN VFR...WITH JUST THE
CHANCE OF A FEW SHOWERS.

OUTLOOK...
SATURDAY...VFR WITH A CHANCE OF LATE AFTERNOON SHOWERS ACROSS
FAR WESTERN NEW YORK.
SATURDAY NIGHT...MVFR WITH SHOWERS AND A CHANCE OF THUNDERSTORMS.
SUNDAY...MAINLY VFR WITH A CHANCE OF MORNING SHOWERS EAST OF
KROC/KDSV.
MONDAY...VFR.
MONDAY NIGHT AND TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
THROUGH SATURDAY A RELATIVELY WEAK PRESSURE GRADIENT WILL PERSIST
ACROSS THE LOWER LAKES REGION. THIS WILL RESULT IN LIGHT TO MODEST
WINDS PREDOMINATING...ALONG WITH CORRESPONDINGLY MINIMAL WAVES.

A COLD FRONT WILL THEN CROSS THE LOWER LAKES SATURDAY NIGHT...WITH
FRESHENING NORTHWESTERLIES IN ITS WAKE POTENTIALLY BRINGING A ROUND
OF ADVISORY-WORTHY CONDITIONS TO LAKE ONTARIO LATER SATURDAY NIGHT
AND SUNDAY. ON LAKE ERIE WINDS WILL BE A BIT WEAKER AND ALSO MORE
WESTERLY...LIKELY YIELDING CONDITIONS THAT WILL REMAIN BELOW ADVISORY
THRESHOLDS THROUGH THE WEEKEND.

LOOKING A BIT FURTHER OUT INTO EARLY NEXT WEEK...THE RETURN OF HIGH
PRESSURE AND A MUCH WEAKER PRESSURE GRADIENT SHOULD SPELL A RETURN
TO RELATIVELY MINIMAL WINDS AND WAVES FOR BOTH MONDAY AND TUESDAY.

&&

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

&&

$$

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



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