000
FXUS61 KBUF 230746
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
346 AM EDT THU MAY 23 2013

.SYNOPSIS...
LOW PRESSURE TRACKING NORTH OF LAKE ONTARIO WILL DRAG A COLD FRONT 
ACROSS OUR REGION THIS AFTERNOON. SHOWERS WILL LINGER BEHIND THE 
FRONT TONIGHT...THEN DIMINISH FROM WEST TO EAST ON FRIDAY AS DRIER 
AIR WORKS EAST ACROSS THE AREA. MUCH COOLER AIR WILL ALSO FOLLOW THE 
FRONT TONIGHT AND FRIDAY.

&&

.NEAR TERM /THROUGH FRIDAY/...
THE LATEST SURFACE MAP SHOWS LOW PRESSURE CENTERED JUST NORTH OF 
LAKE ONTARIO WITH A COLD FRONT TRAILING WEST ACROSS MICHIGAN. LOW 
LEVEL CONVERGENCE IN THE VICINITY OF THE LOW AND COLD FRONT IS 
INTERACTING WITH THE WARM AND SOMEWHAT UNSTABLE AIR THAT IS STILL IN 
PLACE OVER NEW YORK STATE. THIS IS RESULTING IN SCATTERED TO 
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE CWA EARLY 
THIS MORNING. EXPECT THE STEADIEST RAIN TO IMPACT WESTERN NEW YORK 
WHERE ADDITIONAL LIFT IS BEING GENERATED BY A WELL DEFINED SHORT 
WAVE THAT IS CURRENTLY WORKING EAST ACROSS OHIO AND LAKE ERIE. 

AS THE SURFACE LOW MOVES ACROSS SOUTHERN QUEBEC TODAY...ITS TRAILING 
COLD FRONT WILL CROSS WESTERN AND CENTRAL NEW YORK DURING THE 
AFTERNOON. WHILE INSTABILITY WILL NOT BE THAT FAVORABLE...
LARGE SCALE LIFT ASSOCIATED WITH THE FRONT AND APPROACHING UPPER 
LEVEL TROUGH WILL RESULT IN MORE WIDESPREAD SHOWERS COMPARED TO WHAT 
WE SAW THE PREVIOUS TWO DAYS. WILL CONTINUE TO MENTION A CHANCE FOR 
THUNDERSTORMS ACROSS THE FINGER LAKES AND NORTH COUNTRY WHERE THE 
INSTABILITY WILL BE A LITTLE GREATER. 

THE SHOWERS ASSOCIATED WITH THE PASSING FRONT WILL KEEP TEMPERATURES 
15 TO 20 DEGREES COOLER THAN YESTERDAY'S HIGHS. BEHIND THE 
FRONT...TEMPERATURES WILL LIKELY HOLD STEADY OR SLOWLY FALL DURING 
THE AFTERNOON...ESPECIALLY ACROSS THE FAR WEST WHERE READINGS MAY 
DIP INTO THE UPPER 50S BY LATE AFTERNOON.  

TONIGHT...THE COLD FRONT WILL DRIFT TO THE NEW ENGLAND COAST WHILE 
THE AXIS OF THE UPPER LEVEL SETTLES OVER WESTERN NEW YORK. ABUNDANT 
MOISTURE LINGERING BEHIND THE FRONT AND THE LIFT ASSOCIATED WITH THE 
UPPER TROUGH WILL KEEP SHOWERS GOING THROUGH THE NIGHT. MODEST COLD 
AIR ADVECTION BEHIND THE DEPARTING SURFACE FRONT WILL ALLOW 
TEMPERATURES TO COOL THROUGH THE 40S.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
COOLER AIR WILL FILTER INTO THE REGION BEHIND THE COLD FRONT ON 
FRIDAY AS A SHARP UPPER LEVEL TROF AXIS MOVES SLOWLY ACROSS THE 
REGION FROM WEST TO EAST. ALTHOUGH MODEL QPFS ARE ON THE LIGHT 
SIDE...EXPECT A SOLID AREA OF NON-CONVECTIVE PRECIPITATION 
ASSOCIATED WITH THE UPPER TROF WITH CATEGORICAL POPS. HIGHS WILL BE 
NOTABLY COOLER...WITH TEMPERATURES ONLY IN THE 50S ON FRIDAY. 

THE UPPER LEVEL TROF WILL SLOWLY TRACK EAST...AND IS FORECAST TO 
EVENTUALLY CLOSE OFF ACROSS NEW ENGLAND ON SATURDAY. THERE IS SOME 
DISAGREEMENT IN MODEL GUIDANCE IN HOW QUICKLY AND WHERE THE CLOSED 
UPPER LOW WILL ULTIMATELY DEVELOP. IN GENERAL...00Z RUNS OF THE AMERICAN 
NAM/GFS/SREF MODELS ARE SLOWER IN CLOSING THE LOW OFF WHICH WOULD 
KEEP IT WELL TO THE EAST OF OUR REGION. THE EUROPEAN/UKMET/GGEM 
CLOSE THE LOW OFF MORE QUICKLY AND FURTHER TO THE WEST. IF THE 
LATTER VERIFY...CLOUDS AND SOME SHOWERS TO LINGER IN THE EASTERN 
LAKE ONTARIO REGION THROUGHOUT THE WEEKEND. AT THIS POINT...FEEL AN 
ENSEMBLE OF ALL AVAILABLE GUIDANCE IS THE BEST APPROACH UNTIL 
GUIDANCE COMES INTO BETTER AGREEMENT.

EITHER WAY...EXPECT AREAS WEST OF ROCHESTER WILL REMAIN DRY...AND 
WITH A FAIR AMOUNT OF SUNSHINE. EAST OF LAKE ONTARIO MAY SEE A 
SHOWER...DEPENDING ON THE POSITION OF THE UPPER LOW. TEMPERATURES 
WILL BE BELOW NORMAL THROUGH THE PERIOD...BUT WILL GRADUALLY 
MODERATE DURING THE WEEKEND. EXPECT HIGHS MAINLY IN THE LOWER 60S ON 
SATURDAY AND THE MID TO UPPER 60S ON SUNDAY. SIGNIFICANTLY COOLER 
TEMPERATURES ARE POSSIBLE EAST OF LAKE ONTARIO...WHERE CLOUDS AND 
PERHAPS SOME SHOWERS WILL KEEP THINGS COOLER.

ON FRIDAY NIGHT THERE IS A POTENTIAL FOR PATCHY FROST IN THE 
INTERIOR VALLEYS OF THE SOUTHERN TIER. A MODEST PRESSURE GRADIENT 
SHOULD PREVENT WIDESPREAD FROST...HOWEVER TEMPERATURES IN THE 
SHELTERED VALLEYS MAY PUSH THE FREEZING MARK. LOWS SHOULD BE 
SLIGHTLY WARMER ON SATURDAY NIGHT...IN THE UPPER 30S TO LOWER 40S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE UPPER LOW ACROSS NEW ENGLAND WILL WEAKEN AND EXIT INTO THE 
CANADIAN MARITIMES...LEAVING COOL CANADIAN HIGH PRESSURE ACROSS OUR 
REGION FOR THE MAJORITY OF THE PERIOD. THIS WILL RESULT IN A QUIET 
WEATHER PATTERN WITH NO PRECIPITATION EXPECTED. THE DRY AIRMASS IN 
PLACE WILL LIKELY RESULT IN A WIDE DIURNAL RANGE IN TEMPERATURES. 
THE COOLEST PERIOD LOOKS TO BE MONDAY WITH OVERNIGHT LOWS FALLING 
INTO THE MID 30S AND LOWER 40S AND HIGHS IN THE MID TO UPPER 60S. 
THESE TEMPERATURES WOULD SUGGEST SOME FROST POTENTIAL ESPECIALLY FOR 
THE NORMALLY COLDER LOCATIONS OF THE SOUTHERN TIER AND AREAS EAST OF 
LAKE ONTARIO. IT IS LIKELY THAT HEADLINES WILL BE NEEDED AT SOME 
POINT DURING THIS PERIOD.

A GRADUAL WARMING TREND WILL THEN OCCUR THROUGH MID WEEK AS THE HIGH 
SHIFT SLIGHTLY TO THE EAST ALLOWING FOR A MORE SOUTHERLY FLOW WITH 
HIGHS REACHING NORMAL OR SLIGHTLY ABOVE NORMAL BY MID WEEK WITH 
READINGS IN THE 70S.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
SCATTERED TO NUMEROUS SHOWERS WILL CONTINUE TO LIFT NORTH ACROSS THE 
AREA EARLY THIS MORNING. SOME OF THE SHOWERS ACROSS WESTERN NEW YORK 
WILL BE HEAVY ENOUGH TO LOWER VSBYS TO MVFR FOR BRIEF PERIODS. 
THERE SHOULD BE ENOUGH WIND DURING THE EARLY MORNING HOURS TO  
PRECLUDE THE DEVELOPMENT OF FOG DESPITE THE VERY MOIST AIRMASS IN 
PLACE. 

A COLD FRONT THAT TRAILS LOW PRESSURE OVER SOUTHERN QUEBEC WILL 
CROSS WESTERN AND CENTRAL NEW YORK THIS AFTERNOON. THE WILL PROVIDE 
ADDITIONAL FOCUS FOR SHOWERS...ESPECIALLY DURING THE AFTERNOON AS 
THE BULK OF THE RAIN BEGINS TO TAKE RESIDENCE BEHIND THE SURFACE 
COLD FRONT. CIGS/VSBY SHOULD INITIALLY BE VFR...THEN DROP TO MVFR 
LATE IN THE DAY AS TEMPERATURES COOL WHILE ABUNDANT MOISTURE REMAINS 
IN PLACE. 

SHOWERS WILL CONTINUE BEHIND THE FRONT TONIGHT AS THE UPPER LEVEL 
TROUGH WORKS INTO NEW YORK STATE. THE PRESENCE OF ABUNDANT MOISTURE 
...COOLING TEMPERATURES AND A NORTHERLY UPSLOPE FLOW BEHIND THE 
DEPARTED FRONT WILL LIKELY RESULT IN WIDESPREAD MVFR TO IFR 
CONDITIONS.  

OUTLOOK...  
FRIDAY...MVFR IMPROVING TO VFR AS SHOWERS DIMINISH. 
SATURDAY THROUGH MONDAY...VFR.

&&

.MARINE...
LOW PRESSURE CENTERED JUST NORTH OF LAKE ONTARIO WILL MOVE SLOWLY TO 
THE NORTHEAST AND PUSH A COLD FRONT ACROSS WESTERN AND CENTRAL NEW 
YORK THIS AFTERNOON. A BRISK NORTHERLY FLOW BEHIND THE FRONT WILL 
LIKELY RESULT IN SCA CONDITIONS TONIGHT THROUGH FRIDAY MORNING.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON EDT FRIDAY 
         FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM 
         EDT FRIDAY FOR LOZ043-044.
         SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON EDT 
         FRIDAY FOR LOZ042.
         SMALL CRAFT ADVISORY FROM 2 AM TO NOON EDT FRIDAY FOR 
         LOZ045.

&&

$$

SYNOPSIS...TJP
NEAR TERM...TJP
SHORT TERM...APFFEL
LONG TERM...APFFEL/TMA
AVIATION...TJP
MARINE...TJP