Special Marine Warning 52, NWS Buffalo, NY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
711 PM EDT SAT JUN 28 2008

.SYNOPSIS...
LOW PRESSURE OVER THE CENTRAL GREAT LAKES WILL MOVE SLOWLY TO THE
NORTHEAST...TRACK JUST SOUTH OF JAMES BAY SUNDAY THEN LIFT OUT INTO
QUEBEC ON MONDAY AND TUESDAY. MOIST AIR CIRCULATING AROUND THIS
SYSTEM WILL GIVE US A CHANCE THROUGH THE EARLY PART OF NEXT WEEK.
HIGH PRESSURE WILL BRING SOME CLEARING ON WEDNESDAY BEFORE AN
APPROACHING COLD FRONT BRINGS A CHANCE FOR MORE SHOWERS THURSDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
ISSUED AN UPDATE FOR SVR TSTM WATCH #635 WHICH IS IN EFFECT UNTIL 1
AM FOR MOST OF THE CWA EXCEPT FOR JEFFERSON AND LEWIS COUNTIES, THE
OPEN WATERS OF LAKE ONTARIO AND NEARSHORES OF LK ONTARIO FROM MEXICO
BAY TO THE ST LAWRENCE AND NEARSHORE OF LAKE ERIE FROM RIPLEY TO
DUNKIRK. MAIN THREAT IS LARGE HAIL AND DAMAGING WINDS.

AS OF MID AFTERNOON THERE WAS A CLOSED UPPER LOW OVER THE CENTRAL
GREAT LAKES AND SOUTHWEST FLOW OF HUMID...MID TO UPPER 60 DEW POINT
AIR ACROSS OUR REGION. THE MOST IMPORTANT FEATURE IS A MID LEVEL JET
     WHICH IN CONJUNCTION WITH DIURNAL INSTABILITY...WAS PRODUCING A
WELL ORGANIZED BAND OF CONVECTION TO OUR WEST. AS OF 19Z THE
ACTIVITY EXTENDED FROM NEAR LONG POINT ONTARIO TO CENTRAL OHIO. AS
OF YET THERE IS NO EVIDENCE OF 69 DEGREE LAKE ERIE HAVING ANY
NEGATIVE IMPACT ON THIS ACTIVITY. WE EXPECT IT TO STAY IN TACT AS
IS MOVES ACROSS OUR CWA DURING THE EVENING AND EARLY OVERNIGHT
HOURS. CONSIDERING INCREASING BULK SHEAR AND DIURNAL
INSTABILITY...SPC STILL HAS US IN A SLIGHT RISK AREA FOR SEVERE
AND VERY CLOSE TO A MODERATE RISK AREA THAT RUNS FROM NORTHWEST
PENNSYLVANIA TO THE CENTRAL OHIO VALLEY. WE MAY HAVE TO DEAL WITH
A SEVERE THUNDERSTORM WATCH.

WE WILL CARRY LIKELY POPS FOR THE ABOVE MENTIONED ACTIVITY BUT ONLY
KEEP IT IN FOR A FEW HOURS FOR ANY ONE POINT AND THEN CUT IT OFF
FAIRLY SHARPLY. SATELLITE LOOPS SHOW A DISTINCT CLEARING TREND
BEHIND THIS SYSTEM.

SUNDAY BECOMES THE MOST DIFFICULT PART OF THIS FORECAST. MODEL
OUTPUT IS IN PRETTY GOOD AGREEMENT IN LAKING THE UPPER LOW TO OUR
NORTH AND WEST. SREF MEMBERS INDICATE THAT THE COLDEST CORE AT 500
MB WILL SKIRT US AS WELL. THE BULK OF THE SREF MEMBERS ALSO LOWER
OUR SURFACE DEW POINTS TO AROUND 60 AND DROP THE PWAT CONSIDERABLY
FROM WHAT THEY WERE TODAY. MOST UNSTABLE CAPES ALSO DROP. THE ONE
FLY IN THE OINTMENT IS THAT MORE THAN 90 PERCENT OF THE MEMBERS
INDICATE 10M TO 6KM BULK SHEAR GREATER THAN 40 KNOTS INTO THE
AFTERNOON. WE WILL GO WITH MAINLY LIKELY POPS ACROSS THE CWA DURING
THE DAY SUNDAY WITH SOME POPS AS LOW AS THE 40S FOR THE NORTHWEST
SECTION OF THE STATE. EVEN WITH THE LIKELY POPS THOUGH IT SHOULD
STILL REMAIN RAIN FREE THE VAST MAJORITY OF THE TIME.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
THE WEATHER WILL REMAIN UNSETTLED SUNDAY NIGHT TROUGH TUESDAY AS
THE SLOW MOVING UPPER LEVEL TROUGH MAINTAINS ITS INFLUENCE ON OUR
AREA. THE GENERAL TREND WILL REFLECT BELOW AVERAGE TEMPERATURES
ALONG WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING
TIMES OF PEAK DIURNAL HEATING.

THE FORECAST DETAILS...A SURFACE TROUGH...ASSOCIATED WITH A SOUTHERN
EXTENSION OF THE MAIN UPPER LEVEL TROUGH...WILL APPROACH WESTERN NEW
YORK BY MONDAY MORNING...THEN TRACK EAST ACROSS OUR CWA MONDAY
AFTERNOON. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY COMBINED WITH
THE ADDED LIFT FROM SEVERAL PASSING SHORT WAVES WILL GENERATE
SCATTERED SHOWERS AND THUNDERSTORMS...ESPECIALLY MONDAY AFTERNOON
WHEN LIKELY POPS WILL BE HIGHLIGHTED. EXPECT THE SHOWERS TO DIMINISH
WITH THE LOSS DAYTIME HEATING MONDAY NIGHT.

THE SURFACE REFLECTION OF THE UPPER LEVEL TROUGH WILL NOT BE AS WELL
DEFINED ON TUESDAY...BUT THE MODELS STILL MAINTAIN THE INTEGRITY OF
THE UPPER TROUGH AS IT DRIFTS INTO EASTERN NEW YORK STATE TUESDAY
AFTERNOON. THEREFORE...WILL LEAVE IN LOW CHANCE POPS FOR THIS
PERIOD. A FEW SHOWERS MAY LINGER EAST OF LAKE ONTARIO THROUGH THE
FIRST HALF OF TUESDAY NIGHT...BUT THE REST OF THE AREA SHOULD SEE
DRY CONDITIONS AS HIGH PRESSURE BUILDS INTO THE LOWER GREAT LAKES.

IN TERMS OF TEMPERATURES...RATHER COOL CONDITIONS WILL BE THE RULE
ON MONDAY WHERE READINGS MAY NOT GET ABOVE 70...ESPECIALLY ACROSS
THE FAR WESTERN PART OF THE STATE WHERE SHOWERS WILL LIKELY BEGIN
SOONER. TEMPERATURES WILL MODERATE INTO THE LOWER TO MID 70S AS THE
INFLUENCE FROM THE STUBBORN TROUGH DIMINISHES.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
EXPECT GENERALLY DRY CONDITIONS TO FINALLY RETURN ON WEDNESDAY AS
HIGH PRESSURE RIDGES NORTH FROM THE OHIO VALLEY...ALTHOUGH THERE MAY
BE A CHANCE OF A FEW SHOWERS NORTH OF THE SOUTHERN TIER AND UPPER
GENESEE VALLEY DURING THE AFTERNOON AS LOW LEVEL MOISTURE BEGINS TO
POOL AHEAD OF AN APPROACHING CENTRAL GREAT LAKES COLD FRONT. SHOWERS
AND POSSIBLE THUNDERSTORMS WILL BECOME MORE WIDESPREAD ON THURSDAY
AS THE FRONT DROPS SOUTH ACROSS NEW YORK STATE. THE FRONT IS
FORECAST TO STALL SOUTH OF NEW YORK STATE FRIDAY AND SATURDAY. A
WEAK WAVE MOVING EAST ALONG THE BOUNDARY MAY BRING A CHANCE OF
SHOWERS FRIDAY AND SATURDAY.

&&

.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z THE BULK OF THE SHOWER AND THUNDERSTORM ACTIVITY WAS
ACROSS THE FINGER LAKES REGION WITH LOCALIZED IFR AND MVFR
CONDITIONS. IT WAS TRACKING STEADILY TO THE EAST. OUTSIDE OF THAT
ACTIVITY WE EXPECT PRIMARILY VFR CONDITIONS INTO MID AFTERNOON BUT
A GROWING THREAT OF NEW THUNDERSTORM DEVELOPMENT...ESPECIALLY
ALONG OLD BOUNDARIES FROM EARLIER CONVECTION AND ALSO ALONG LAKE
BREEZE BOUNDARIES. WE ARE ALSO WATCHING A WELL ORGANIZED LINE OF
CONVECTION MOVING EAST FROM A LINE FROM WINDSOR TO TOLEDO. IF THIS
HOLDS TOGETHER IT WILL IMPACT OUR REGION THIS EVENING. OVERNIGHT
SHOULD BE MAINLY VFR AND THEN RENEWED CONVECTION SUNDAY.

OUTLOOK...
MONDAY AND TUESDAY...MAINLY VFR BUT A CHANCE OF THUNDERSTORMS IN
THE AFTERNOON AND EVENING BOTH DAYS.
WEDNESDAY...VFR.
THURSDAY...VFR BUT A CHANCE OF SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
SOUTHWEST WINDS CHANNELING UP LAKE ERIE WILL ALLOW WAVES TO BUILD TO
JUST BELOW THE ADVISORY NEEDED FOR A SMALL CRAFT ADVISORY THIS
EVENING. OTHERWISE...EXPECT UNSETTLED WEATHER CONDITIONS ON BOTH
LAKES THROUGH THE REST OF THE WEEKEND INTO EARLY NEXT WEEK AS A SLOW
MOVING LOW TRACKS ACROSS SOUTHERN ONTARIO AND QUEBEC.

&&

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

&&

SYNOPSIS...TJP
NEAR TERM...JJP/SAGE
SHORT TERM...TJP
LONG TERM...TJP
AVIATION...SAGE
MARINE...TJP