Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 010626
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
226 AM EDT WED OCT 1 2014

.SYNOPSIS...
AN UPPER LEVEL LOW WILL BRING CLOUDS AND SCATTERED SHOWERS TO
SOUTHERN AND WESTERN NEW YORK THROUGH EARLY WEDNESDAY. LINGERING
CLOUDS WILL BREAK UP LATER IN THE DAY WEDNESDAY WITH A RETURN TO DRY
AND MILD WEATHER THROUGH THURSDAY. A STRONG COLD FRONT IS THEN
EXPECTED TO CROSS THE REGION ON FRIDAY...BRINGING A GREATER
LIKELIHOOD OF SHOWERS FOLLOWED BY MUCH COOLER TEMPERATURES FOR THE
UPCOMING WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
WATER VAPOR IMAGERY SHOWING UPPER LOW THAT WAS RESPONSIBLE FOR THE
EARLIER SHOWER AND THUNDERSTORM ACTIVITY NOW STARTING TO WEAKEN AS
IT PULLS OFF TO THE SOUTHEAST ACROSS CENTRAL PA. MEANWHILE AN
INVERTED SURFACE TROUGH EXTENDS NORTH OUT OF PA INTO CENTRAL AND
NORTHERN NEW YORK. RADAR IMAGERY SHOWING ALL SHOWER ACTIVITY NOW
CONFINED TO CENTRAL PA UNDER THE UPPER LOW AND ALONG THE INVERTED
TROUGH...WITH MUCH OF WESTERN AND NORTHCENTRAL NEW YORK NOW DRY AS
WE HAVE LOST MUCH OF THE INFLUENCE FROM THE DEPARTING UPPER LOW.

STILL CAN`T RULE OUT A SPOTTY SHOWER OR TWO ACROSS SOUTHEASTERN
PORTIONS OF THE FORECAST AREA THROUGH THE REMAINDER OF THE
OVERNIGHT AND EARLY WEDNESDAY...HOWEVER BELIEVE MOST AREAS WILL
REMAIN DRY. NORTHEASTERLY FLOW WEST OF THIS TROUGH WILL ALSO DRAW
MOIST AIR SOUTH FROM LAKE ONTARIO AND PRODUCE PATCHY FOG AND LOW
CLOUDS THROUGH WEDNESDAY MORNING ACROSS MUCH OF WESTERN NEW YORK.

HIGH PRESSURE NORTH OF LAKE ONTARIO WILL MOVE TOWARD THE SAINT
LAWRENCE VALLEY ON WEDNESDAY AND WILL RIDGE SOUTHWARD WITH DRIER AIR
AND BRING ABOUT A CLEARING TREND LATE IN THE DAY ON WEDNESDAY.

TEMPERATURES WILL RANGE MOSTLY IN THE MID 50S OVERNIGHT WITH A
MODERATING INFLUENCE FROM LAKE ONTARIO AND THE THICKER CLOUD COVER.
HIGHS ON WEDNESDAY WILL BE MAINLY UPPER 60S TO LOW 70S...THE
WARMER SPOTS ACROSS THE NORTH COUNTRY WHERE CLOUDS WILL BE THINNER
AND MORE SUNSHINE.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
OUR PROLONGED STRETCH OF INDIAN SUMMER WEATHER WILL COME TO AN END
DURING THIS PERIOD AS A STRONG PACIFIC JET RACING ACROSS BRITISH
COLUMBIA WILL PUSH A DEEPENING LONGWAVE TROUGH ACROSS THE CENTER OF
THE COUNTRY...WHICH IN TURN WILL DISLODGE RIDGING OVER THE LOWER
GREAT LAKES. THIS PROCESS WILL EVENTUALLY LEAD TO THE DEVELOPMENT OF
AN ANOMALOUSLY DEEP CLOSED LOW OVER THE GREAT LAKES REGION. BY THE
TIME THE ASSOCIATED PATTERN CHANGING SFC COLD FRONT MAKES ITS WAY
ACROSS OUR FORECAST AREA...TEMPERATURES WILL HAVE AVERAGED ABOVE
NORMAL FOR NEARLY TWO WEEKS.

THE SEMBLANCE OF A REX BLOCK (RIDGING OVER QUEBEC/CUTOFF LOW OVER
NEW ENGLAND) FOUND OVER THE ST LAWRENCE VALLEY WEDNESDAY NIGHT WILL
PUSH EAST TO THE CANADIAN MARITIMES DURING THE DAY THURSDAY. THIS
GENERAL SCENARIO WILL PROMOTE FAIR DRY WEATHER FOR OUR REGION
WEDNESDAY NIGHT...THEN A SECOND REINFORCING RIDGE WILL BUILD ACROSS
THE LOWER GREAT LAKES IN ITS IMMEDIATE WAKE TO SUPPLY US WITH A
BEAUTIFUL DAY ON THURSDAY. SUBSIDENCE ASSOCIATED WITH THE RIDGE WILL
COMBINE WITH A DEEPENING SOUTHERLY FLOW TO SUPPORT WIDESPREAD
AFTERNOON TEMPERATURES IN THE MID 70S. SITES ACROSS THE GENESEE
VALLEY AND IN THE DOWNSLOPE AREAS NEAR THE IAG ESCARPMENT SHOULD
MAKE IT INTO THE UPPER 70S.

A 130KT H25 JET OVER THE NORTHERN ROCKIES THURSDAY EVENING WILL DIG
INTO A DEEPENING LONGWAVE TROUGH OVER THE NORTHERN PLAINS DURING THE
OVERNIGHT...WHICH WILL SUPPORT THE CONSOLIDATION OF A SFC LOW OVER
THE UPPER GREAT LAKES. THIS WILL INTENSIFY A DOWNSTREAM LOW LEVEL
JET OVER MICHIGAN...WHICH IN COMBINATION WITH RIDGING TO OUR EAST
WILL KEEP A VERY WARM SOUTHERLY FLOW IN PLACE OVER OUR REGION. THE
RESULT WILL BE A WARM DRY NIGHT WITH MIN TEMPERATURES GENERALLY
WITHIN A FEW DEGREES OF 60. THESE READINGS WILL BE SOME 15 DEG F
ABOVE NORMAL EARLY OCT VALUES...OR CLOSE TO WHERE WE SHOULD BE FOR
DAYTIME HIGHS.

ON FRIDAY...A FEED OF 80-100 WINDS AT H25 WILL CONTINUE TO POUR INTO
THE LONGWAVE TROUGH OVER THE MISSISSIPPI VALLEY. THIS WILL ENCOURAGE
THE DEVELOPMENT OF A CUT OFF LOW NEAR THE ARROWHEAD OF MINNESOTA
WHILE THE ASSOCIATED SFC LOW WILL LIFT DUE NORTH. THE MOVEMENT OF
THE DEEPENING SFC LOW SHOULD BE A CLUE AS TO THE DOWNSTREAM FLOW
OVER OUR REGION. AN ANOMALOUSLY STRONG 50KT SOUTHERLY LOW LEVEL JET
OVER THE LOWER GREAT LAKES WILL NOT ONLY SUPPORT ONE MORE WARM DAY
OVER OUR FORECAST AREA...BUT WILL ALSO KEEP THE EASTWARD PROGRESSION
OF THE SFC FRONT AND ITS ASSOCIATED PCPN TO A CRAWL. HAVE THUS
CONTINUED THE TREND OF SLOWING THE ADVANCEMENT OF THE SHOWERS...IN
THIS CASE BY SOME 3-6 HOURS. THE BULK OF THE DAY SHOULD THUS BE RAIN
FREE FOR SITES EAST OF THE GENESEE VALLEY...WITH LIKELY POPS NOT
EXPECTED FOR THE FAR WESTERN COUNTIES UNTIL LATE. AGAIN...MANY AREAS
WILL EXPERIENCE MAX TEMPS IN THE MID TO UPPER 70S.

THE COLD FRONT...WHICH WILL BE ON OUR DOORSTEP STRETCHING FROM LAKE
HURON TO CENTRAL LAKE ERIE FRIDAY EVENING...WILL GRUDGINGLY PUSH
ACROSS OUR FORECAST AREA DURING THE COURSE OF FRIDAY NIGHT. THE LOW
LEVEL FORCING FROM THE COLD FRONT WILL BE ACCOMPANIED BY A
RELATIVELY NARROW 3 HR WINDOW OF ENHANCED LIFT SUPPLIED BY THE RR
ENTRANCE REGION OF A CYCLONICALLY CURVED 120KT H25 JET OVER SOUTHERN
ONTARIO. WILL HOLD ONTO THE HIGH LIKELY POPS WITH THIS PACKAGE...BUT
AS THE CONFIDENCE IN THE TIMING OF THIS FRONTAL PASSAGE BECOMES
GREATER...CAN EASILY SEE POPS BEING RAISED TO CATEGORICAL. GIVEN
LAPSE RATES OF LESS THAN 6 DEG C/KM...WILL CONTINUE TO LEAVE OUT THE
MENTION OF ANY THUNDER. THAT BEING SAID...THERE SHOULD BE DEEP
ENOUGH LIFT AND SUFFICIENT MOISTURE TO SUPPORT SOME HEAVIER SHOWERS.

H85 TEMPS THAT WILL BE IN THE VCNTY OF 12-14C AHEAD OF THE FRONT
FRIDAY EVENING WILL PLUNGE TO ARND 2C (WRN COUNTIES) BY DAYBREAK.
THIS SHOULD ENABLE TEMPS OVER THE FAR WESTERN COUNTIES TO BOTTOM OUT
AT NORMAL LEVELS (40S).

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
TEMPERATURES WILL AVERAGE NEAR TO BELOW NORMAL DURING THIS PERIOD AS
A PERSISTENT LONGWAVE TROUGH WILL BE CENTERED OVER ONTARIO AND THE
GREAT LAKES REGION. THE CORE OF THE COLDEST AIR ASSOCIATED WITH THIS
TROUGH WILL BE OVER THE GREAT LAKES REGION DURING THE SECOND HALF OF
THE WEEKEND. AS THE NEGATIVELY TILTED LONGWAVE ROTATES POLEWARD
ACROSS EASTERN CANADA EARLY NEXT WORK WEEK...A NEAR ZONAL PACIFIC
FLOW WILL PROMOTE A MODIFICATION OF THE AIRMASS OVER GREAT LAKES.

FOR SATURDAY...THE SFC COLD FRONT WILL PUSH AWAY FROM OUR REGION VIA
THE ST LAWRENCE VALLEY WHILE A SHORTWAVE RIDGE WILL BUILD ACROSS THE
LOWER GREAT LAKES AND OUR FORECAST AREA IN ITS WAKE. THIS RIDGING
WILL WORK AGAINST ORGANIZED LAKE DRIVEN SHOWER ACTIVITY...EVEN
THOUGH H85 TEMPS NEAR 2C WILL SUPPLY PLENTY OF INSTABILITY OVER THE
LAKES. WILL CARRY LIKELY POPS FOR THE MORNING ACROSS THE NORTH
COUNTRY WITH GENERALLY LOW CHC POPS ELSEWHERE. THE BULK OF THE
MIDDAY AND AFTERNOON SHOULD BASICALLY BE PCPN FREE...BUT CHILLY AS
TEMPERATURES WILL CLIMB INTO THE UPPER 50S TO LOWER 60S.

THE CYCLONIC FLOW FOUND ABV 10K FT WILL WORK TO THE SFC SATURDAY
NIGHT AS THE AFOREMENTIONED RIDGING WILL PUSH EAST. THIS WILL
ENCOURAGE THE DEVELOPMENT OF SOME LAKE DRIVEN RAIN SHOWERS EAST OF
LK ERIE AND PARTICULARLY EAST OF LK ONTARIO IN THE VCNTY OF THE TUG.
LOW TEMPS WILL RANGE FROM THE 30S ACROSS THE SRN TIER TO THE LOWER
40S MOST ELSEWHERE.

AS THE CORE OF THE NEGATIVELY TILTED UPPER LEVEL TROUGH ADVANCES TO
THE NORTH ON SUNDAY...THE LOW LEVEL FLOW WILL BACK AND THIS WILL
SEND INCREASINGLY DISORGANIZED LAKE EFFECT RAIN SHOWERS TO PARTS OF
THE IAG FRONTIER AND ACROSS THE HEART OF JEFFERSON COUNTY. H85 TEMPS
STRADDLING THE ZERO DEG ISOTHERM WILL SUGGEST DAYTIME HIGHS WILL
ONLY BE IN THE 50S.

A BROAD AREA OF LOW PRESSURE IS FORECAST TO DRIFT ACROSS THE GREAT
LAKES AND SOUTHERN ONTARIO ON MONDAY. THIS WILL BRING THE CHANCE FOR
SOME SHOWERS TO ALL OF OUR REGION...ALTHOUGH THE BULK OF THE DAY
SHOULD BE PCPN FREE.

FINALLY FOR TUESDAY...LOW LEVEL RIDGING OVER THE MISSISSIPPI VALLEY
WILL DRIFT EAST ACROSS THE UPPER GREAT LAKES AND OHIO VALLEY WHILE
THE AFOREMENTIONED SFC LOW WILL WORK ITS WAY DOWN THE ST LAWRENCE
VALLEY. THE EXITING SFC LOW WILL ONCE AGAIN POSE THE OPPORTUNITY FOR
SOME BADLY NEEDED RAIN SHOWERS.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
OVERNIGHT...NOW THAT SHOWERS HAVE DISSIPATED ACROSS THE
AREA...NORTHEASTERLY WINDS HAVE BROUGHT WIDESPREAD IFR/LOW MVFR
CONDITIONS TO AREAS SOUTH OF LAKE ONTARIO. WHILE MAINLY VFR
CONDITIONS WILL REMAIN ACROSS THE EASTERN LAKE ONTARIO REGION...WITH
SOME MVFR VSBYS POSSIBLY AT THE KART TERMINAL...AND POSSIBLE IFR
CIGS ACROSS THE HIGHER TERRAIN LATER TONIGHT. EXPECT ANY FOG TO BURN
OFF BY MID MORNING...WHILE MVFR/IFR CIGS SOUTH OF LAKE ONTARIO WILL
TAKE MUCH OF THE MORNING TO BREAK UP UNDER MOIST NORTHEASTERLY
UPSLOPE FLOW OFF OF LAKE ONTARIO...WITH CONDITIONS POSSIBLY NOT
BECOMING VFR UNTIL EARLY WEDNESDAY AFTERNOON. VFR CONDITIONS CAN
THEN BE EXPECTED FROM WEDNESDAY AFTERNOON THROUGH THE REMAINDER OF
THE TAF PERIOD.

OUTLOOK...
WEDNESDAY THROUGH THURSDAY...VFR...EXCEPT FOR LOCALIZED IFR IN
SOUTHERN TIER VALLEY FOG BETWEEN 06Z-15Z EACH DAY.
FRIDAY...VFR LOWERING TO MVFR WITH SHOWERS BECOMING LIKELY.
SATURDAY AND SUNDAY...MVFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
AN UPPER LEVEL LOW...AND WEAK SURFACE LOW WILL MOVE EAST ACROSS
PENNSYLVANIA OVERNIGHT. THIS WILL PRODUCE A NORTHEASTERLY WIND
AROUND 15-20 KNOTS ON LAKE ONTARIO THROUGH WEDNESDAY MORNING.
CENTRAL LAKE ONTARIO BUOY SHOWING SUSTAINED WINDS OF 20-23 KNOTS
WITH WAVES ALREADY AT 4 FEET...AND OLCOTT HARBOR NOW SUSTAINED AT 19
KNOTS WITH GUSTS TO 22 KNOTS. WITH THIS IN MIND HAVE DECIDED TO
ISSUE A SMALL CRAFT ADVISORY FROM SODUS BAY...WEST TO THE NIAGARA
RIVER...WHERE THE STRONGER WINDS WILL PRODUCE WAVES OF 3-5 FEET
THROUGH LATE MORNING/EARLY AFTERNOON WEDNESDAY. OTHERWISE EXPECT
WINDS AROUND 10 KNOTS AND WAVES NEAR 1 FOOT ON LAKE ERIE.

WINDS AND WAVES WILL DIMINISH WEDNESDAY AFTERNOON AS HIGH PRESSURE
AGAIN BUILDS ACROSS THE LOWER LAKES REGION.

LATE IN THE WEEK...A STRONG AREA OF LOW PRESSURE IS EXPECTED TO LIFT
ACROSS THE GREAT LAKES REGION ON FRIDAY...WHILE SWINGING A STRONG
TRAILING COLD FRONT ACROSS THE LOWER LAKES. THE TIGHTENING PRESSURE
GRADIENT ASSOCIATED WITH THE LOW WILL LEAD TO A PERIOD OF STRONGER
WINDS...WITH ADVISORY-LEVEL WINDS AND WAVES BECOMING POSSIBLE.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LOZ042-
         043.

&&

$$

SYNOPSIS...JM/WCH
NEAR TERM...JM/WCH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JM/TMA
MARINE...JM/WCH







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