Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 021142
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
742 AM EDT THU OCT 2 2014

.SYNOPSIS...
PATCHY LOW CLOUDS AND FOG EARLY THIS MORNING WILL GIVE WAY TO
INCREASING SUNSHINE TODAY AS A RIDGE OF HIGH PRESSURE REMAINS
OVERHEAD. AN AREA OF LOW PRESSURE WILL THEN MOVE INTO THE GREAT
LAKES ON FRIDAY WITH AN ASSOCIATED STRONG COLD FRONT CROSSING
WESTERN NY FRIDAY NIGHT AND THE EASTERN LAKE ONTARIO REGION ON
SATURDAY WITH OCCASIONAL SHOWERS. VERY WARM TEMPERATURES THROUGH
FRIDAY WILL GIVE WAY TO MUCH COOLER WEATHER BEHIND THE COLD FRONT
FOR THE WEEKEND AND EVEN SOME LAKE EFFECT RAIN NORTHEAST OF THE
LAKES.

&&

.NEAR TERM /THROUGH TONIGHT/...
11-3.9 MICRON SATELLITE IMAGERY SHOWING AREAS OF LOW CLOUDS AND FOG
EARLY THIS MORNING...WITH THE MOST WIDESPREAD STRATUS FOUND ACROSS
THE INTERIOR SOUTHERN TIER AND FINGER LAKES. SOME OF THE FOG WILL BE
LOCALLY DENSE...INCLUDING ACROSS THE SOUTHERN TIER WITH VSBY AT OR
BELOW 1/4 MILE. THE STRATUS IS NOT ANYWHERE NEAR AS EXTENSIVE OR
THICK AS YESTERDAY...SO EXPECT IT TO MIX OUT MUCH EASIER WITH THE
BULK OF THE LOW CLOUDS AND FOG DISSIPATING BY MID MORNING IN MOST
AREAS AND LATE MORNING ACROSS THE SOUTHERN TIER.

OTHERWISE FOR TODAY SURFACE HIGH PRESSURE WILL REMAIN CENTERED OVER
THE CANADIAN MARITIMES WITH A RIDGE EXTENDING BACK INTO NEW ENGLAND
AND THE LOWER LAKES. THIS WILL PROVIDE ANOTHER DRY DAY WITH A GOOD
DEAL OF SUNSHINE FOLLOWING THE EARLY MORNING FOG/STRATUS. MOISTURE
PROFILES AND NAM CU-RULE SUGGEST SOME CUMULUS WILL DEVELOP BY MIDDAY
WITH DAYTIME HEATING...ESPECIALLY ACROSS WESTERN NY WHERE SKY COVER
MAY BE MORE OF A MIX OF SUN AND CLOUDS. 850MB TEMPS OF AROUND +11C
WILL YIELD HIGHS IN THE MID 70S ACROSS LOWER ELEVATIONS AND AROUND
70 ON THE HILLS. RELATIVELY WEAK SYNOPTIC SCALE FLOW AND STRONG
DIFFERENTIAL HEATING WILL ALLOW LOCAL LAKE BREEZES TO FORM...
ESPECIALLY ALONG THE SOUTH SHORE OF LAKE ONTARIO WEST OF ROCHESTER
WITH COOLER TEMPS ALONG THE IMMEDIATE LAKESHORE.

TONIGHT HIGH PRESSURE WILL DRIFT FARTHER EAST WHILE LOW PRESSURE
DEEPENS AND MOVES INTO THE CENTRAL LAKES BY 12Z FRIDAY. THIS WILL
ALLOW SOUTHERLY RETURN FLOW TO INCREASE OVERNIGHT AND KEEP
TEMPERATURES VERY MILD FOR EARLY OCTOBER. EXPECT LOWS TO RANGE FROM
THE UPPER 50S TO AROUND 60 ON THE LAKE PLAINS OF WESTERN NY TO THE
LOWER 50S IN THE COOLEST SOUTHERN TIER VALLEYS AND TUG HILL REGION.
THESE LOWS WILL LIKELY OCCUR EARLY...WITH TEMPERATURES RISING
TOWARDS DAYBREAK AS SOUTHERLY FLOW INCREASES. THE DIURNAL CUMULUS
WILL DISSIPATE IN THE EARLY EVENING. SOME LIMITED HIGH CIRRUS LEVEL
CLOUDINESS WILL INCREASE ACROSS WESTERN NY OVERNIGHT. BOTH THE NAM
AND GFS ALSO SUGGEST ANOTHER ROUND OF LOW STRATUS ACROSS THE HIGHER
TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES LATER TONIGHT. WITH
INCREASING DOWNSLOPE FLOW THIS STRATUS WILL REMAIN CONFINED TO THE
HIGHER TERRAIN WITH LITTLE OR NO CHANCE OF IT SPREADING TO THE LAKE
PLAINS.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
EXPECT ONE LAST BALMY FALL DAY ON FRIDAY...BEFORE A SIGNIFICANT
PATTERN CHANGE GETS UNDERWAY MOVING INTO THE COMING WEEKEND AS A
LONGWAVE TROUGH BECOMES ESTABLISHED ACROSS THE GREAT LAKES...
USHERING IN AN EXTENDED PERIOD OF COOL AND UNSETTLED WEATHER
ACROSS WESTERN AND NORTH-CENTRAL NEW YORK.

OPENING THE PERIOD ON FRIDAY...WE WILL HAVE ONE LAST WARM DAY BEFORE
MOTHER NATURE REMINDS US THAT IS INDEED OCTOBER. LATEST MODEL
CONSENSUS HAS THE RAINFALL ASSOCIATED WITH A STRONG COLD FRONT
APPROACHING THE REGION NOW MOVING IN JUST A FEW HOURS
EARLIER...WHICH WILL BRING THE CHANCE OF SHOWERS FIRST INTO FAR
SOUTHWESTERN NEW YORK BY MID AFTERNOON...WHILE THE PERSISTENT
DOWNSLOPING AHEAD OF THE FRONT SHOULD HELP KEEP NORTHWESTERN ZONES
DRY THROUGH AT LEAST THE LATE AFTERNOON/EARLY EVENING. A GOOD DEAL
OF SUNSHINE COMBINED WITH A GUSTY SOUTH SOUTHEASTERLY WINDS WILL
HELP BOOST HIGH TEMPS INTO THE LOWER TO MID 70S FOR MOST
LOCALES...WITH UPPER 70S LIKELY IN THE FAVORED DOWNSLOPE AREAS.
WOULD NOT BE SURPRISED TO SEE A FEW 80 DEGREE READINGS IN THE
TYPICALLY WARMER LOCATIONS.

FRIDAY NIGHT THE TRANSITION TO FALL WILL BEGIN IN EARNEST AS A
STRONG COLD FRONT SWEEPS THROUGH WESTERN AND NORTHCENTRAL NEW YORK
OVERNIGHT INTO SATURDAY MORNING. THE COLD FRONT WILL BE SUPPORTED BY
A 100+KT UPPER LEVEL JET AND POWERFUL SHORTWAVE ALOFT ROTATING
THROUGH THE BASE OF THE LONGWAVE TROUGH JUST TO OUR WEST. THIS WILL
BRING A WIDESPREAD SWATH OF WELCOMED RAINFALL TO THE ENTIRE REGION.
A DECENT PLUME OF MOISTURE ALONG THE BOUNDARY COMBINED WITH PLENTY
OF LARGE SCALE LIFT WILL LEAD TO RAINFALL AMOUNTS BY MIDDAY SATURDAY
AVERAGING BETWEEN 0.25-0.50" AREA WIDE...WITH A BIT MORE QPF LIKELY
IN SOME LOCATIONS. MODELS HAVE COME INTO GOOD AGREEMENT ON THE
TIMING...SO WITH THIS IN MIND AND AFTER COLLABORATION WITH
SURROUNDING OFFICES...HAVE OPTED TO RAISE POPS TO CATEGORICAL DURING
THIS PERIOD. BEST CHANCE FOR A RUMBLE OF THUNDER WOULD BE TOWARD THE
PENNSYLVANIA LINE...HOWEVER OVERALL INSTABILITY STILL APPEARS FAIRLY
WEAK. THIS COMBINED WITH FROPA OCCURRING DURING THE
OVERNIGHT/SATURDAY MORNING TIMEFRAME...SO WILL LEAVE OUT ANY MENTION
OF THUNDER AT THIS TIME.

WEAK INDUCED SURFACE RIDGING DUE TO GOOD SUBSIDENCE RIGHT BEHIND THE
FRONT COMBINED WITH A DRY SLOT ALOFT MOVING OVERHEAD SHOULD DRY
THINGS OUT SOMEWHAT IN THE WAKE OF THE FRONTAL PASSAGE ACROSS
WESTERN NEW YORK SATURDAY MORNING...WITH THE SAME SCENARIO EXPECTED
ACROSS THE EASTERN LAKE ONTARIO REGION BY LATE IN THE DAY...AS
SHOWERS HANG ON HERE INTO THE EARLY TO MID AFTERNOON. EXPECT SOME
BREAKS OF SUN AT TIMES SATURDAY (ESPECIALLY ACROSS WESTERN NEW
YORK)...HOWEVER BY LATE IN THE DAY EXPECT TO SEE LAKE CLOUDS
STARTING TO DEVELOP DOWNWIND OF THE LAKES ON A SOUTHWESTERLY FLOW
(JUST A HINT OF THINGS TO COME). STRONG COLD AIR ADVECTION ON THIS
BRISK SOUTHWESTERLY FLOW BEHIND THE FRONT WILL KEEP HIGHS ON
SATURDAY FROM GETTING OUT OF THE 50S IN MOST LOCATIONS...WITH A FEW
LOCATIONS ACROSS THE LOWER TERRAIN FROM THE FINGER LAKES EASTWARD
POSSIBLY TOUCHING 60 BRIEFLY BEFORE THE CORE OF THE COLD AIR
ADVECTION ENSUES.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS WE MOVE INTO SATURDAY NIGHT...WRAPAROUND MOISTURE COINCIDENT
WITH INCREASINGLY COLD TEMPERATURES ALOFT WILL WORK ITS WAY ACROSS
THE LOWER GREAT LAKES. THIS WILL SET THE STAGE FOR THE DEVELOPMENT
OF LAKE EFFECT RAIN SHOWERS DOWNWIND OF LAKES ERIE AND ONTARIO.
WHILE INITIAL DEVELOPMENT MAY BE STUNTED BY THE PRESENCE OF A
DECENT AMOUNT OF VERTICAL SHEAR SATURDAY EVENING DUE IN PART TO
SUBTLE INDUCED SURFACE RIDGING IN THE WAKE OF THE COLD FRONTAL
PASSAGE...HOWEVER WINDS BECOME BETTER ALIGNED OVERNIGHT SATURDAY
NIGHT AS THE MAIN SHORTWAVE DRIVING THE UPPER TROUGH LIFTS ACROSS
NORTHERN NEW ENGLAND AND UPPER LEVEL FLOW BECOMES BETTER ALIGNED
IN A SOUTHWESTERLY DIRECTION. WITH 850MB TEMPS FALLING TO AROUND
0C AND LAKE ERIE A COMPARATIVELY BALMY +19C...LAKE-INDUCED
INSTABILITY WILL BE SUBSTANTIAL WITH CAPES POTENTIALLY APPROACHING
1000-1500J/KG AND EQUILIBRIUM LEVELS APPROACHING 15-20KFT. GIVEN
THIS...THERE WILL ALSO BE A CHANCE FOR THUNDER. IN
ADDITION...GIVEN HOW COLD TEMPERATURES ARE ALOFT COMBINED WITH THE
GOOD AMOUNT OF INSTABILITY...GRAUPEL WILL BE POSSIBLE IN ANY
HEAVIER SHOWERS. WINDS SEEM A BIT TOO STRONG FOR WATERSPOUT
FORMATION OVER THE LAKES...HOWEVER THIS WILL NEED TO BE MONITORED
IN CASE CONDITIONS BECOME MORE FAVORABLE. THIS SCENARIO WILL BE A
LITTLE SLOWER TO EVOLVE ON LAKE ONTARIO OWING TO IT`S CLOSER
POSITION TO THE EXITING SHORTWAVE AND ASSOCIATED SHEAR. THE COLD
AIR ADVECTING INTO THE REGION WILL DROP TEMPERATURES DOWN INTO THE
MID TO UPPER 30S...WITH LOWER 40S CONFINED TO AREAS NEAR THE
LAKESHORES.

LAKE EFFECT SHOWERS WILL LIKELY TAPER OFF SOME DURING THE LATE
MORNING/AFTERNOON ON SUNDAY AS DIURNAL EFFECTS AND INCREASED SHEAR
ALOFT WILL DISRUPT ANY LAKE BANDS SOMEWHAT...HOWEVER A CHANCE OF
LAKE ENHANCED SHOWERS WILL PERSIST DOWNWIND OF THE LAKES THROUGH
MUCH OF SUNDAY AS A SHORTWAVE ALOFT TRACKS ACROSS THE LOWER GREAT
LAKES. IN FACT THE WEATHER THROUGH THE MIDDLE OF NEXT WEEK WILL
CONTINUE TO BE GENERALLY CLOUDY WITH PERIODS OF SHOWERS AS A PARADE
OF SHORTWAVES ROTATE THROUGH THE BASE OF THE LONGWAVE TROUGH
BECOMING ESTABLISHED OVER THE GREAT LAKES. TEMPERATURES WILL REMAIN
ON THE COOL SIDE WITH HIGHS IN THE 50S SUNDAY...WITH LOWS IN THE
UPPER 30S TO LOWER 40S SUNDAY NIGHT. THERE WILL BE SOME MODERATION
MONDAY THROUGH WEDNESDAY AS A PACIFIC BASED AIRMASS INVADES THE
NORTHERN TIER OF THE COUNTRY. EXPECT HIGHS GENERALLY IN THE
60S...WITH UPPER 50S ACROSS THE TYPICAL COOLER LOCATIONS.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
EXTENSIVE SHALLOW LOW LEVEL MOISTURE REMAINS TRAPPED BENEATH A
SUBSIDENCE AND RADIATION INVERSION ACROSS THE LOWER LAKES REGION
EARLY THIS MORNING. THIS WILL CONTINUE TO PRODUCE POCKETS OF IFR IN
FOG AND LOW STRATUS THROUGH MID MORNING. THE MOST WIDESPREAD IFR
STRATUS AND FOG WILL BE FOUND ACROSS THE INTERIOR SOUTHERN TIER AND
FINGER LAKES.

THE LOW STRATUS AND FOG WILL BURN OFF BY MID TO LATE MORNING. THIS
WILL LEAVE VFR TO PREVAIL WITH A RIDGE OF HIGH PRESSURE STILL
OVERHEAD. EXPECT SOME CUMULUS TO DEVELOP WITH DAYTIME HEATING. THE
CUMULUS WILL DISSIPATE BY LATE AFTERNOON OR EARLY EVENING AND LEAVE
SOME CIRRUS LEVEL CLOUDINESS ADVANCING INTO WESTERN NY AHEAD OF THE
NEXT SYSTEM.

MODEL GUIDANCE SUGGESTS ANOTHER ROUND OF LOW STRATUS FOR THE HIGHER
TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES LATE TONIGHT AND EARLY
FRIDAY MORNING WITH IFR ACROSS THE HIGHER TERRAIN. UNLIKE THE PAST
FEW DAYS...INCREASING SOUTHEAST DOWNSLOPE FLOW WILL MAKE IT
VIRTUALLY IMPOSSIBLE FOR THIS TO ADVANCE INTO THE LOWER ELEVATIONS
OF THE LAKE PLAINS WHERE MOST OF THE TAF SITES ARE LOCATED.

OUTLOOK...
FRIDAY...MAINLY VFR. A CHANCE OF SHOWERS LATE.
FRIDAY NIGHT...AREAS OF MVFR/IFR WITH SHOWERS.
SATURDAY...AREAS OF MVFR/IFR EAST OF LAKE ONTARIO IN SHOWERS.
VFR/MVFR FARTHER WEST WITH A CHANCE OF SHOWERS.
SUNDAY...VFR/MVFR IN STRATUS. LAKE EFFECT SHOWERS LIKELY NORTHEAST
OF THE LAKES WITH LOCAL IFR.
MONDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
HIGH PRESSURE CENTERED OVER THE CANADIAN MARITIMES WITH A RIDGE
EXTENDING BACK INTO NEW ENGLAND AND THE LOWER LAKES WILL PROVIDE ONE
MORE DAY OF RELATIVELY LIGHT WINDS AND FLAT WAVE ACTION. THE HIGH
WILL DRIFT FARTHER EAST TONIGHT INTO FRIDAY WHILE LOW PRESSURE MOVES
INTO THE CENTRAL LAKES. SOUTHERLY WINDS WILL INCREASE AHEAD OF THIS
SYSTEM WITH WINDS APPROACHING SMALL CRAFT ADVISORY CRITERIA.

A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT INTO EARLY
SATURDAY. SOUTH TO SOUTHEAST WINDS WILL INCREASE TO NEAR 30 KNOTS
JUST AHEAD OF THE FRONT FRIDAY NIGHT ACROSS NORTHEAST LAKE ONTARIO.
BEHIND THE FRONT WINDS WILL BECOME SOUTHWEST AND INCREASE TO NEAR 30
KNOTS ON BOTH LAKES EARLY SATURDAY. THERE IS AT LEAST A LOW
POTENTIAL OF A SHORT PERIOD OF MARGINAL GALE FORCE WINDS ON LAKE
ERIE SATURDAY MORNING. OTHERWISE EXPECT A LONG LASTING PERIOD OF
SOLID SMALL CRAFT ADVISORY CONDITIONS ON BOTH LAKES FROM FRIDAY
THROUGH THE WEEKEND.

SATURDAY AND SUNDAY LAKE INDUCED INSTABILITY WILL BE STRONG AND DEEP
ENOUGH TO CONSIDER WATERSPOUT POTENTIAL...HOWEVER IT APPEARS
BOUNDARY LAYER WINDS MAY BE A LITTLE TOO STRONG FOR WATERSPOUT
FORMATION.

&&

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

&&

$$

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





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