Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 201946
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
346 PM EDT MON OCT 20 2014

.SYNOPSIS...
LOW PRESSURE WILL SLOWLY CROSS THE REGION TONIGHT THROUGH TUESDAY
AND PRODUCE OCCASIONAL SHOWERS. LOW PRESSURE WILL MOVE TO THE EAST
COAST BY WEDNESDAY BUT REMAIN CLOSE ENOUGH TO KEEP PLENTY OF CLOUDS
AND SHOWERS THROUGH MUCH OF THE WEEK. THE RAIN WILL BE MOST
PREVALENT ACROSS CENTRAL NY BUT A FEW SHOWERS WILL ALSO PERSIST
ACROSS THE WESTERN END OF THE STATE. TEMPERATURES WILL REMAIN ON THE
COOL SIDE THROUGH MOST OF THE WEEK BEFORE WARMER AND DRIER WEATHER
DEVELOPS FOR NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
RADAR IMAGERY SHOWING A FEW SPRINKLES AND VERY LIGHT SHOWERS
CROSSING THE REGION THIS AFTERNOON...WITH THE MOST CONCENTRATED
ACTIVITY CROSSING LAKE ONTARIO INTO THE SAINT LAWRENCE VALLEY. MOST
AREAS WILL SEE NOTHING MORE THAN A SPRINKLE THROUGH EARLY EVENING.

WATER VAPOR IMAGERY AND OBJECTIVE RUC ANALYSIS SHOWS A MID LEVEL
TROUGH CROSSING THE CENTRAL LAKES...WITH A POTENT VORTICITY MAXIMA
NOTED ENTERING WESTERN OHIO. THIS FEATURE HAS A CONCENTRATED BAND OF
SHOWERS ASSOCIATED WITH IT...AND IS FORECAST TO ENTER WESTERN NY BY
MID EVENING. GIVEN THE TRAJECTORY OF THE STRONGEST ASCENT IN ADVANCE
OF THIS VORTICITY MAXIMA...EXPECT THE MOST ORGANIZED SHOWERS THIS
EVENING TO PASS ACROSS THE WESTERN SOUTHERN TIER...AND THIS HAS
SUPPORT FROM SHORT TERM MESOSCALE MODEL GUIDANCE INCLUDING THE NAM
AND GEM SOLUTIONS.

OVERNIGHT THE SURFACE LOW WILL MOVE SOUTHEAST ACROSS SOUTHERN
ONTARIO AND REACH WESTERN NY BY 12Z TUESDAY...AN UNUSUAL LOW TRACK
FROM A CLIMATOLOGY STANDPOINT. ALOFT THE MID LEVEL TROUGH WILL
CONTINUE TO DIG INTO THE LOWER LAKES AND BEGIN TO DEVELOP A CLOSED
CIRCULATION. SHOWERS WILL BECOME MORE WIDESPREAD ACROSS MUCH OF THE
REGION...AND WILL BE MOST CONCENTRATED WITHIN AREAS OF DPVA AHEAD OF
SEVERAL NOTABLE VORTICITY MAXIMA ROTATING AROUND THE DEVELOPING
CLOSED LOW. THE FIRST OF THESE WILL MOVE FROM THE WESTERN SOUTHERN
TIER THIS EVENING ACROSS THE FINGER LAKES TO THE NORTH COUNTRY BY
EARLY TUESDAY...WEAKENING WITH EASTERN EXTENT. THE SECOND IS
FORECAST TO WRAP INTO WESTERN NY ON TUESDAY. WHILE THE FORCING AND
MOISTURE COMING TOGETHER YIELD A HIGH PROBABILITY OF RAIN TONIGHT
AND TUESDAY...THE TRANSIENT AND COMPLEX NATURE OF FORCING WITH THE
LOW CROSSING DIRECTLY OVERHEAD WILL MAKE TIMING AND PLACEMENT OF THE
PERIODS OF ENHANCED RAIN DIFFICULT AT BEST. WITH THIS IN MIND HAVE
GONE WITH HIGH CATEGORICAL POPS BUT KEPT THE WORDING OF OCCASIONAL
SHOWERS.

RAINFALL AMOUNTS WILL BE TRICKY TO PLACE AS WELL...WITH HIGHER
AMOUNTS REMAINING RELATIVELY LOCALIZED. IN GENERAL EXPECT AMOUNTS OF
A QUARTER TO THIRD OF AN INCH IN MOST AREAS...BUT SOME MESOSCALE
MODEL GUIDANCE SUGGESTS A PERSISTENT AREA OF CONVERGENCE AND UPSLOPE
FLOW ACROSS THE WESTERN SOUTHERN TIER WHICH MAY PRODUCE LOCAL
AMOUNTS OF UP TO THREE QUARTERS OF AN INCH.

EXTENSIVE CLOUD COVER WILL KEEP A RELATIVELY SMALL DIURNAL RANGE IN
TEMPERATURES OVER THE NEXT 24 HOURS. EXPECT LOWS IN THE MID 40S IN
MOST AREAS TONIGHT WITH LOWER 40S IN THE COOLEST SOUTHERN TIER
VALLEYS AND TUG HILL REGION...AND UPPER 40S ALONG THE IMMEDIATE
LAKESHORES. HIGHS ON TUESDAY WILL BE IN THE MID 50S IN MOST AREAS.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
EXITING UPPER WAVE ANCHORING THE BROADER MID LEVEL TROUGH
AMPLIFICATION WILL CLOSE OFF AS IT SETTLES INTO THE MID ATLANTIC
REGION DURING THE MID WEEK PERIOD. THE EXTENSIVE MOIST CYCLONIC FLOW
WILL PUSH WESTWARD INTO WESTERN NEW YORK TUESDAY NIGHT AND THE FIRST
PART OF WEDNESDAY...BRINGING WIDESPREAD SHOWER ACTIVITY. WE SHOULD
SEE THE SHOWER ACTIVITY DIMINISH FROM WEST TO EAST LATER WEDNESDAY
AS THE MID/UPPER LEVEL CIRCULATION DRIFTS OFF THE EAST COAST AND DRY
AIR ALOFT ENCROACHES ACROSS THE LOWER GREAT LAKES FROM THE WEST.
HOWEVER...DEVELOPING NORTH NORTHEAST FLOW WHICH WILL LIKELY SUPPORT
ADDITIONAL SHOWER DEVELOP SOUTH OF LAKE ONTARIO AND IN FAVORED
UPSLOPE AREAS. THERE SHOULD BE AN UPTICK TO THE SHOWER ACTIVITY
THURSDAY AS THE LOW DRIFTS BACK TO THE WEST AND A FRESH SLUG OF
ATLANTIC MOISTURE WRAPS INTO THE AREA FROM THE NORTH. THE COOL
NORTHERLY FLOW AND ABUNDANT MOISTURE PRODUCING PLENTY OF CLOUD
COVER...TEMPERATURES WILL RUN ON THE COOL SIDE OF AVERAGE THROUGHOUT
THE PERIOD WITH HIGHS GENERALLY IN THE MID 40S TO LOWER 50S.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
MEDIUM RANGE GUIDANCE REMAINING CONSISTENT...AS LOW PRESSURE OFF THE
NEW ENGLAND COAST TRACKS SLOWLY NORTH INTO THE GULF OF MAINE AND
ATLANTIC MOISTURE. PLENTY OF MARITIME AIR WILL BE WRAPPED WESTWARD
INTO THE REGION CONTINUING THE DREARY WEATHER PATTERN THROUGH
FRIDAY. THE DEEPER MOISTURE AND GREATER POTENTIAL FOR RAINFALL
REMAINS FOCUSED EAST OF THE GENESEE VALLEY.

AN IMPROVEMENT LOOKS TO COME BY THE WEEKEND AND EARLY NEXT WEEK.
THE LOW FINALLY LIFTS OFF TO THE NORTHEAST ACROSS THE CANADIAN
MARITIMES...AND SHORTWAVE RIDGING MOVES ACROSS THE EASTERN GREAT
LAKES ALLOWING FOR DRIER CONDITIONS AND A GRADUAL WARMING TREND.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
MAINLY VFR WILL LAST INTO EARLY EVENING BEFORE CONDITIONS BEGIN TO
DETERIORATE. THE ONE EXCEPTION WILL BE NEAR KIAG WHERE LOCAL SSW
FLOW OFF LAKE ERIE WILL CONTINUE TO PRODUCE AREAS OF MVFR CIGS
THROUGH LATE AFTERNOON. ANY SHOWERS THROUGH 22Z WILL BE VERY LIGHT
WITH NO REDUCTION IN CIGS/VSBY.

EARLY THIS EVENING SHOWERS WILL BEGIN TO INCREASE ACROSS THE
REGION...WITH SHOWERS BECOMING MOST WIDESPREAD AT FIRST ACROSS THE
WESTERN SOUTHERN TIER. CIGS WILL DETERIORATE TO MVFR THEN IFR
THROUGH MID TO LATE EVENING ACROSS THE WESTERN SOUTHERN TIER. THE
NIAGARA FRONTIER INCLUDING KBUF/KIAG/KROC SHOULD STAY MAINLY VFR AT
FIRST WITH ANY SHOWERS REMAINING LIGHT AND SSW FLOW HELPING TO
DOWNSLOPE AWAY ANY LOWER CIGS.

OVERNIGHT SHOWERS WILL BECOME MORE WIDESPREAD...AND LOWER CIGS WILL
ALSO BECOME MORE WIDESPREAD WITH MVFR AT LOWER ELEVATIONS AND IFR
ACROSS HIGHER TERRAIN. BY TUESDAY MORNING LOW PRESSURE WILL BE
LOCATED DIRECTLY OVER WESTERN NY. NORTHEAST WINDS WILL BECOME
ESTABLISHED ON THE NORTHERN EDGE OF THE LOW ACROSS THE NIAGARA
FRONTIER AND RESULT IN IFR CIGS BECOMING WIDESPREAD ACROSS WESTERN
NY BY AROUND 12Z TUE. EXPECT THIS IFR TO PERSIST THROUGH MUCH OF THE
DAY WITH VERY MOIST LOW LEVELS AND NORTHEAST FLOW. OCCASIONAL
SHOWERS WILL PERSIST AS WELL...AND COMBINE WITH BR TO PRODUCE AREAS
OF MVFR/IFR VSBY ON TUESDAY.

OUTLOOK...
TUESDAY NIGHT...MVFR/IFR WITH OCCASIONAL SHOWERS.
WEDNESDAY THROUGH FRIDAY...AREAS OF MVFR WITH A CHANCE OF RAIN...
RAIN LIKELY ACROSS CENTRAL AND NORTHERN NY.
SATURDAY...MAINLY VFR.

&&

.MARINE...
MODERATE SOUTH-SOUTHWEST WINDS ON LAKE ERIE WILL CONTINUE THROUGH
EARLY EVENING BEFORE DIMINISHING TONIGHT. THIS WILL MAINTAIN
MARGINAL SMALL CRAFT ADVISORY CONDITIONS ON LAKE ERIE FOR A FEW MORE
HOURS. LOW PRESSURE WILL CROSS THE LOWER LAKES LATE TONIGHT AND
EARLY TUESDAY MORNING WITH A PERIOD OF RELATIVELY LIGHT WINDS RIGHT
NEAR THE LOW CENTER.

LATER TUESDAY MORNING NORTHEAST WINDS WILL INCREASE ON LAKE
ONTARIO...THEN INCREASE FURTHER TO AROUND 25 KNOTS TUESDAY AFTERNOON
AS THE PRESSURE GRADIENT QUICKLY TIGHTENS BEHIND THE DEPARTING LOW.
THIS WILL BRING HIGHER END SMALL CRAFT ADVISORY CONDITIONS TO THE
SOUTH SHORE OF LAKE ONTARIO TUESDAY THROUGH AT LEAST WEDNESDAY.
NORTHEAST WINDS MAY ALSO INCREASE ENOUGH TO PRODUCE SMALL CRAFT
ADVISORY CONDITIONS ON LAKE ERIE LATER TUESDAY AFTERNOON THROUGH
WEDNESDAY MORNING.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ040-
         041.
         SMALL CRAFT ADVISORY FROM 2 PM TUESDAY TO 11 AM EDT
         THURSDAY FOR LOZ043.
         SMALL CRAFT ADVISORY FROM 5 PM TUESDAY TO 11 AM EDT
         THURSDAY FOR LOZ044.
         SMALL CRAFT ADVISORY FROM 11 AM TUESDAY TO 11 AM EDT
         THURSDAY FOR LOZ042.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...HITCHCOCK
MARINE...HITCHCOCK





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