Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 171829
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
229 PM EDT SUN AUG 17 2014

.SYNOPSIS...
HIGH PRESSURE OVER NORTHERN ONTARIO WILL GRADUALLY SETTLE ACROSS THE
LOWER GREAT LAKES. THIS WILL PROVIDE OUR REGION WITH AT LEAST TWO
DAYS OF DRY FAIR WEATHER...ALTHOUGH TEMPERATURES WILL REMAIN ON THE
COOL SIDE OF NORMAL. AS TEMPERATURES CLIMB TO ABOVE NORMAL LEVELS
LATER IN THE WEEK...OUR CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
INCREASE AS WELL.

&&

.NEAR TERM /THROUGH TONIGHT/...
IT HAS BEEN A MIXTURE OF SUN AND CLOUDS THIS MORNING ACROSS WESTERN
AND NORTH-CENTRAL NEW YORK AS LOW LEVEL MOISTURE AND EARLY MORNING
STRATUS HAS BEEN MIXING OUT ACROSS THE AREA...HOWEVER IT LOOKS LIKE
IT MAY BE A CLOUDIER AFTERNOON THAN ORIGINALLY EXPECTED. A LOOK AT
VISIBLE SATELLITE IMAGERY SHOWS A LARGE SWATH OF DENSE CLOUD COVER
OVER EASTERN ONTARIO AND QUEBEC...LIKELY THE RESULT OF LOW LEVEL
MOISTURE TRAPPED UNDER THE HIGH PRESSURE SUBSIDENCE INVERSION. WHILE
THIS CLOUD COVER IS GRADUALLY ERODING FROM THE NORTHWEST...CLOSER TO
THE CENTER OF THE HIGH OVER WESTERN ONTARIO...THIS IS NOT LIKELY TO
HAPPEN BEFORE THIS AREA OF MOISTURE THAT IS POORLY HANDLED BY THE
MODELS MAKES IT OVER OUR AREA. THE ONLY AREA THAT MAY ESCAPE THE
ENCROACHING CLOUD COVER WILL BE FAR WESTERN NEW YORK.

ALTHOUGH CLOUD COVER WILL LIKELY BE ON THE INCREASE...THE MOIST
LAYER IS QUITE SHALLOW...SO NO PRECIPITATION IS EXPECTED. HIGHS ARE
STILL EXPECTED TO TOP OUT IN THE UPPER 60S TO LOWER 70S...MAINLY
DEPENDENT ON HOW MUCH CLOUD COVER MATERIALIZES.

TONIGHT`S FORECAST IS COMPLICATED BY THE ABOVE MENTIONED ABUNDANCE
OF LOW LEVEL MOISTURE LURKING JUST TO OUR NORTH. IT WILL BE A RACE
BETWEEN THE MOISTURE ADVECTING INTO THE REGION FROM THE NORTH AND IT
BEING ERODED FROM THE NORTHWEST BY DRIER AIR OVER WESTERN ONTARIO.
THE MODELS ARE OF LITTLE HELP AT THE MOMENT...HOWEVER LOOKING AT
SATELLITE TRENDS...IT APPEARS THAT FAR WESTERN NEW YORK MAY SEE
CLEARING SKIES BY LATE EVENING...HOWEVER FOR AREAS SOUTH AND EAST OF
LAKE ONTARIO THE FORECAST IS CONSIDERABLY MURKIER. GIVEN LIGHT
NORTHERLY LOW-LEVEL SYNOPTIC FLOW EXPECTED TO CONTINUE TONIGHT...A
DIRECTION THAT IS CLIMATOLOGICALLY FAVORABLE FOR THE DEVELOPMENT OF
LOW CLOUDS SOUTH OF LAKE ONTARIO...AM GOING TO BUMP THE CLOUD COVER
UP TO AT LEAST MOSTLY CLOUDY FOR THE TIME BEING. THIS WILL HAVE THE
EFFECT OF BUMPING LOWS UP A FEW DEGREES AS WELL...AM GOING IN THE
MID TO UPPER 50S TONIGHT.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
DURING THE COURSE OF MONDAY AND MONDAY NIGHT...SPRAWLING HIGH
PRESSURE INITIALLY CENTERED ALONG THE ONTARIO-QUEBEC BORDER WILL
SLOWLY DRIFT SOUTHEASTWARD INTO EASTERN NEW YORK AND NEW ENGLAND...
WHILE A WEAK WAVE OF LOW PRESSURE SLIDES ACROSS THE OHIO VALLEY AND
VIRGINIAS. IT NOW APPEARS THAT THIS LATTER FEATURE WILL REMAIN FAR
ENOUGH TO OUR SOUTH FOR THE WEATHER ACROSS OUR AREA TO REMAIN QUIET
AND TOTALLY DRY...SO HAVE PULLED ANY REMAINING POPS ACROSS THE
SOUTHERN TIER FROM THE FORECAST.

ON TUESDAY...THE NARROWING SURFACE RIDGE WILL SLIDE OUT INTO NEW
ENGLAND...WHILE THE NEXT NOTEWORTHY MID LEVEL TROUGH AND ASSOCIATED
BROAD SURFACE LOW PUSHES INTO THE WESTERN AND CENTRAL GREAT LAKES.
WHILE THIS SYSTEM WILL REMAIN FAR ENOUGH TO OUR WEST FOR THE BULK OF
OUR AREA TO ENJOY ANOTHER DRY DAY...A WEAK SOUTHEASTERLY RETURN FLOW
DEVELOPING ACROSS PA/SOUTHERN NEW YORK WILL HELP TO INCREASE LOW
LEVEL MOISTURE ACROSS THE SOUTHERN TIER AND INTERIOR SECTIONS OF
FINGER LAKES. COUPLED WITH DIURNAL HEATING...THIS MAY LEAD TO THE
DEVELOPMENT OF SOME SCATTERED SHOWERS/THUNDERSTORMS IN THESE AREAS
DURING THE AFTERNOON...FOR WHICH SOME LOW-MID RANGE CHANCE POPS WILL
BE IN PLAY.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...CONDITIONS SHOULD TREND
DOWNHILL AS THE MID LEVEL TROUGH AND SURFACE LOW TRACK INTO FAR
SOUTHERN ONTARIO...WHILE GRADUALLY PUSHING A WARM FRONT INTO NEW
YORK STATE FROM THE OHIO VALLEY. INCREASING MOISTURE...LIFT...AND
INSTABILITY ASSOCIATED WITH THE WARM FRONT WILL SPREAD THE RISK OF
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA FROM SOUTHWEST
TO NORTHEAST DURING THIS TIME FRAME...WITH THESE BEGINNING AS EARLY
AS LATER TUESDAY NIGHT ACROSS FAR WESTERN NEW YORK.

WITH RESPECT TO TEMPERATURES...THESE WILL START OFF THE PERIOD BELOW
NORMAL...BEFORE RISING BACK TO MID-AUGUST AVERAGES BY MIDWEEK WITH
THE APPROACH OF THE WARM FRONT/ATTENDANT STEADY WARMING OF OUR
AIRMASS. MORE SPECIFICALLY...HIGHS IN THE LOWER TO MID 70S ON MONDAY
WILL RISE TO AROUND 80 IN MOST LOCATIONS BY WEDNESDAY...WHILE
NIGHTTIME LOWS INITIALLY RANGING IN THE MID 40S TO MID 50S CLIMB TO
THE LOWER TO MID 60S BY THE END OF THE PERIOD. THE WARMING TREND
WILL ALSO BE ACCOMPANIED BY A NOTICEABLE INCREASE IN HUMIDITY
LEVELS...WITH DEWPOINTS GRADUALLY CLIMBING BACK TO THE LOWER TO MID
60S BY WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
IN THE EXTENDED PORTION OF THE FORECAST...THE MEDIUM RANGE GUIDANCE
IS IN ROUGH AGREEMENT THAT THE MID LEVEL TROUGH OVER OUR REGION AT
THE START OF THE PERIOD WILL GRADUALLY GET SHUNTED TO OUR SOUTH AND
EAST...AS STRENGTHENING RIDGING DEVELOPS OVER EASTERN CANADA.

WHILE THE VARIOUS GUIDANCE PACKAGES DIFFER SOME ON THE EXACT DETAILS
REGARDING THIS EVOLUTION IN THE PATTERN...IN GENERAL THIS SHOULD
RESULT IN THE WARM FRONTAL BOUNDARY/WEAK SURFACE WAVE STALLING OUT
ACROSS OUR REGION ON THURSDAY...BEFORE GRADUALLY GETTING SHUNTED OFF
TO OUR SOUTH AND EAST FRIDAY AND SATURDAY WHILE PROGRESSIVELY DRIER
AND MORE STABLE AIR BUILDS SOUTHWESTWARD ACROSS OUR REGION.

SHOULD THE ABOVE VERIFY...WE CAN EXPECT ANOTHER UNSETTLED DAY ON
THURSDAY WITH ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS...
BEFORE CONDITIONS GRADUALLY TREND DRIER AND QUIETER FOR THE END OF
THE WORK WEEK AND THE BEGINNING OF NEXT WEEKEND. WITH THIS TREND IN
MIND..IN THE FORECAST HAVE INDICATED POPS DIMINISHING FROM THE MID
CHANCE RANGE ON THURSDAY TO THE SLIGHT CHANCE RANGE BY FRIDAY NIGHT
AND SATURDAY.

AS FOR TEMPS...WITH LITTLE NOTEWORTHY WARMING OR COOLING OF OUR
AIRMASS EXPECTED...THESE SHOULD REMAIN NEAR SEASONAL NORMALS RIGHT
THROUGH THE PERIOD...WITH DAYTIME HIGHS AVERAGING OUT IN THE MID TO
UPPER 70S...AND NIGHTTIME LOWS RANGING FROM THE UPPER 50S TO MID 60S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SCT-BKN VFR CIGS COVER MUCH OF WESTERN AND NORTH-CENTRAL NEW YORK
THIS AFTERNOON WITH DENSEST CLOUD COVER BEING FOUND ACROSS THE NORTH
COUNTRY...WHERE CLOUD COVER IS ADVANCING SOUTHEASTWARDS...UNIMPEDED
BY LAKE ONTARIO. THE CLEAREST AREAS CAN BE FOUND ACROSS FAR
SOUTHWEST NEW YORK...WHERE THE LAKE ERIE SHADOW IS IN FULL EFFECT.

SCT-BKN DIURNAL STRATOCU WILL LINGER THROUGH THE AFTERNOON WITH
CLOUD COVER DIMINISHING TO SOME EXTENT THIS EVENING. HOWEVER...AS WE
MOVE DEEPER INTO THE NIGHT...TOWARDS 06Z...LIGHT UPSLOPE NORTHERLY
FLOW OFF OF LAKE ONTARIO COMBINED WITH LINGERING LOW LEVEL MOISTURE
MAY GENERATE STRATUS ACROSS AREAS SOUTH OF THE LAKE BETWEEN
BUF-IAG-ROC-FZY. THERE IS CONSIDERABLE UNCERTAINTY REGARDING THIS
OUTCOME...PARTICULARLY AS DRY AIR ADVANCING FROM NORTHWEST ONTARIO
HAS GRADUALLY BEEN ERODING THE POOL OF MOISTURE TO OUR NORTH...THUS
AM NOT INCLINED TO GO IFR AT THIS TIME...BUT STICK WITH MVFR CIGS.
MVFR CIGS WILL BE A DECENT BET ACROSS THE NORTH COUNTRY OVERNIGHT AS
WELL DUE TO CLOSER PROXIMITY TO THE POOL OF MOISTURE OVER CANADA.

ACROSS THE WESTERN SOUTHERN TIER...LAKE ONTARIO INFLUENCES WILL BE
MINIMAL AND EXPECT WIDESPREAD CLEARING ACROSS THE AREA THIS EVENING.
THIS SHOULD ALLOW FOR THE DEVELOPMENT OF VALLEY FOG LATER
TONIGHT...POTENTIALLY BRINGING IFR CONDITIONS TO KJHW FROM 08-12Z.

LOOK FOR WIDESPREAD IMPROVEMENT TO VFR ACROSS THE FORECAST AREA ON
MONDAY AS HIGH PRESSURE BUILDS OVERHEAD THE LOWER GREAT LAKES.


OUTLOOK...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY THROUGH FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS.

&&

.MARINE...
HIGH PRESSURE OVER NORTHERN ONTARIO THIS MORNING WILL GRADUALLY
SETTLE ACROSS THE UPPER GREAT LAKES THIS AFTERNOON...AND
SOUTHERN ONTARIO TONIGHT AND MONDAY. THE RESULTING WEAK PRESSURE
GRADIENT WILL ONLY RESULT IN MODERATE BREEZES ACROSS LAKES ERIE AND
ONTARIO TODAY...AND GENTLE BREEZES EXPECTED FOR MONDAY. WHILE
SOMEWHAT CHOPPY CONDITIONS WILL PERSIST ON THE EASTERN HALF OF LAKE
ONTARIO THIS MORNING...WAVES WILL CONTINUE TO SUBSIDE THROUGH
MONDAY.

LIGHT WINDS AND NEGLIGIBLE WAVES WILL REMAIN IN PLACE ACROSS THE
LOWER GREAT LAKES ON TUESDAY AS A WARM FRONT WILL APPROACH FROM THE
OHIO VALLEY.

&&

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

&&

$$

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







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