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Area Forecast Discussion
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000
FXUS61 KBUF 042350
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
750 PM EDT TUE AUG 4 2015

.SYNOPSIS...
A SECONDARY COLD FRONT WILL CROSS THE AREA THIS EVENING WITH 
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. FOLLOWING THE PASSAGE OF 
THIS SECOND COLD FRONT...A FEW SCATTERED SHOWERS WILL LINGER ACROSS 
THE NORTH COUNTRY THROUGH WEDNESDAY. OTHERWISE IT WILL TURN DRIER 
AND COOLER FOR THE REMAINDER OF THE WEEK.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
RADAR IMAGERY THIS EVENING SHOWING SCATTERED SHOWERS AND A FEW 
THUNDERSTORMS WITH THE BEST COVERAGE OVER LAKE ONTARIO. THIS IS JUST 
AHEAD OF A SECONDARY COLD FRONT AND AHEAD OF A WEAK MID LEVEL TROUGH 
WHICH IS PROVIDING A BOOST IN LARGE SCALE ASCENT. THE SHOWERS AND 
STORMS WILL MOVE EAST AND IMPACT AREAS ALONG THE SOUTH SHORE OF LAKE 
ONTARIO AND EVENTUALLY THE EASTERN LAKE ONTARIO REGION LATER THIS 
EVENING. MOST OF THESE STORMS WILL JUST CONTAIN DOWNPOURS AND MODEST 
WIND GUSTS...ALTHOUGH A FEW OF THE STRONGER STORMS MAY CONTAIN SMALL 
HAIL AS WELL. FARTHER SOUTH EXPECT MOST AREAS TO STAY DRY ACROSS THE 
SOUTHERN TIER AND FINGER LAKES...ALTHOUGH A FEW ISOLATED SHOWERS 
CANNOT BE RULED OUT.  

BEHIND THE PARENT SHORTWAVE...A WEAK SECONDARY COLD FRONT WILL CROSS 
THE REGION OVERNIGHT. OVERALL THIS WILL RESULT IN REDUCTION OF 
SHOWER AND THUNDERSTORM ACTIVITY OVERNIGHT... AS DRIER AIR AND SOME 
SUBSIDENCE WORK INTO THE AREA BEHIND THE BOUNDARY. THE EXCEPTION IS 
THE EASTERN LAKE ONTARIO REGION WHERE LAKE SURFACE TEMPS TO 850MB 
TEMP DIFFERENCE NEARS 13 DEGREES C WHICH SHOULD BE ENOUGH...WITH 
VERY UNSTABLE LAPSE RATES REMAINING IN PLACE IN THE MID-LEVELS...TO 
PROMOTE SOME LAKE ENHANCEMENT TO THE SHOWERS AND THUNDERSTORMS LATE 
TONIGHT BEHIND THE COLD FRONT. A FEW LAKE ENHANCED SHOWERS ARE ALSO 
POSSIBLE EAST OF LAKE ONTARIO LATE TONIGHT AND EARLY WEDNESDAY 
MAINLY ACROSS CHAUTAUQUA AND SOUTHERN ERIE COUNTIES.

ON WEDNESDAY... TEMPERATURES WILL RUN ABOUT 10 DEGREES F BELOW 
NORMAL AS THE UPPER LEVEL LOW REMAINS OVERHEAD. THE CORE OF GREATEST 
INSTABILITY ALOFT WILL REMAIN OVER THE NORTH COUNTRY AND ADIRONDACKS 
DURING THE DAY ON WEDNESDAY. PURE LAKE EFFECT WOULD NORMALLY FIZZLE 
OUT INTO THE DAY ON WEDNESDAY WITH A LOSS OF CONVERGENCE OVER THE 
LAKE HOWEVER... THE NORTH COUNTRY WILL SEE A MODE CHANGE FROM LAKE 
ENHANCED SHOWERS AND THUNDERSTORMS TO JUST DIURNALLY UNSTABLE 
SHOWERS AND THUNDERSTORMS IN THE UNSTABLE NORTHWESTERLY FLOW AND 
OROGRAPHIC ENHANCEMENT. OTHERWISE... ALL OF WESTERN NEW YORK SHOULD 
SEE A MOSTLY DRY DAY AND PLEASANT DAY ON WEDNESDAY.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
THE UPPER LEVEL TROUGH THAT HAS BEEN BRINGING THE COOLER AND 
UNSETTLED WEATHER TO THE REGION WILL BE IN THE PROCESS OF DEPARTING 
THE REGION AS WE MOVE THROUGH WEDNESDAY NIGHT AND INTO THURSDAY 
MORNING. A FEW SHOWERS WILL BE DIMINISHING DURING THE EVENING HOURS 
ACROSS THE NORTH COUNTRY OWING TO THE COMBINATION OF DIURNAL 
INSTABILITY...COLD AIR ALOFT...AND AREAS OF VORTICITY ROTATING 
AROUND THE LOW CENTERED OVER QUEBEC. PERSISTENT ONSHORE/UPSLOPE FLOW 
WITH NOMINAL LAKE ENHANCEMENT WILL KEEP A LOW CHANCE OF A SHOWER 
POPPING UP SOUTHEAST OF LAKE ONTARIO OVERNIGHT...THOUGH THE 
INCREASINGLY DRY AIR ALOFT WILL SEVERELY LIMIT ANY NASCENT ACTIVITY.

ELSEWHERE...LOOK FOR DRY CONDITIONS TO PERSIST THROUGH THE END OF 
THE WORK WEEK AS THE DEPARTING TROUGH GIVES WAY TO MORE ZONAL FLOW 
ALOFT WITH HIGH PRESSURE AT THE SURFACE WITH ONLY SOME DIURNAL CU 
INLAND TO CONTEND WITH IN THE AFTERNOON ON THURSDAY...GIVING WAY TO 
PARTLY CLOUDY SKIES THURSDAY NIGHT AS THE HIGH MOVES OVERHEAD. 
MID/HIGH CLOUD COVER MAY BE A LITTLE MORE WIDESPREAD NEAR THE PA 
BORDER THURSDAY NIGHT...CLOSER TO A LOW PRESSURE SYSTEM THAT WILL BE 
SLIDING BY WELL TO OUR SOUTH ACROSS THE OHIO VALLEY AND CENTRAL 
APPALACHIANS. OTHERWISE...FRIDAY AND FRIDAY NIGHT SHOULD SEE MUCH OF 
THE SAME AS WEAK SURFACE HIGH PRESSURE REMAINS OVER THE LOWER GREAT 
LAKES.

REGARDING TEMPERATURES...WEDNESDAY NIGHT WILL BE THE COOLEST NIGHT 
OF THE PERIOD AS THE EFFECTS OF THE DEPARTING UPPER LEVEL LOW WILL 
BE MOST KEENLY FELT. LOWS WILL RUN IN THE 50S WITH A FEW SHELTERED 
SPOTS IN THE SOUTHERN TIER POTENTIALLY DIPPING INTO THE UPPER 40S. 
THE COOL AIR ALOFT WILL ONLY SLOWLY MODIFY THROUGH THE REST OF THE 
PERIOD OWING TO WEAK TEMPERATURE ADVECTION WITH HIGHS THURSDAY AND 
FRIDAY RUNNING JUST A COUPLE OF DEGREES BELOW AVERAGE WITH READINGS 
GENERALLY IN THE MID TO UPPER 70S AND LOWS IN THE 50S.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE WEEKEND WILL FEATURE A RETURN TO MORE UNSETTLED WEATHER AS 
SEVERAL UPPER LEVEL VORTICITY MAXIMA STRADDLING THE U.S. CANADIAN 
BORDER OVER THE NORTHERN PLAINS WILL DROP ACROSS THE GREAT LAKES. 
WHILE A LACK OF DEEP MOISTURE AND LACK OF ORGANIZATION SHOULD 
PREVENT THE WEEKEND FROM BEING A COMPLETE WASHOUT...THE SYSTEMS WILL 
AT LEAST PRESENT OPPORTUNITY FOR THE DEVELOPMENT OF SCATTERED 
SHOWERS AND THUNDERSTORMS...PARTICULARLY ON SUNDAY INTO MONDAY AS 
THE LONGWAVE TROUGH BECOMES RE-ESTABLISHED ACROSS THE REGION.  
TEMPERATURES WILL REMAIN WITHIN A COUPLE OF DEGREES OF NORMAL WITH 
HIGHS IN THE MID TO UPPER 70S AND LOWS IN THE MID 50S INLAND TO THE 
LOWER 60S NEAR THE LAKES.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A SECONDARY COLD FRONT AND WEAK MID LEVEL TROUGH WILL CROSS THE 
REGION THIS EVENING AND SUPPORT SCATTERED SHOWERS AND A FEW 
THUNDERSTORMS. THE RAIN IS EXPECTED TO BE MOST WIDESPREAD FROM THE 
SOUTH SHORE OF LAKE ONTARIO TO THE EASTERN LAKE ONTARIO REGION 
INCLUDING KROC-KFZY-KART. VFR WILL PREVAIL...BUT ANY OF THE HEAVIER 
SHOWERS WILL CONTAIN VERY BRIEF MVFR/IFR CONDITIONS. 

OVERNIGHT THE COLD FRONT WILL PUSH EAST OF THE AREA WITH MOST OF THE 
SHOWERS ENDING FROM WEST TO EAST. THE FRONT WILL USHER IN A COOLER 
AIRMASS...AND MAY ACTUALLY BE COOL ENOUGH TO SUPPORT A FEW LAKE 
ENHANCED SHOWERS EAST OF LAKES ERIE AND ONTARIO LATE TONIGHT AND 
WEDNESDAY MORNING. MOST OF THIS SHOULD AVOID THE TAF SITES. LATER 
WEDNESDAY COOL AIR ALOFT AND ANOTHER MID LEVEL TROUGH WILL SUPPORT 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EAST OF LAKE ONTARIO 
INCLUDING KART. A FEW OF THESE SHOWERS MAY BRIEFLY DROP CIGS/VSBY TO 
MVFR...BUT VFR SHOULD PREVAIL ON WEDNESDAY WITH AREAS OF CUMULUS AND 
STRATOCUMULUS FORMING IN THE COOL AIR ALOFT.


OUTLOOK... 
THURSDAY THROUGH SUNDAY...VFR.

&&

.MARINE...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS 
THE LAKES THIS EVENING...WITH THE POTENTIAL FOR GUSTY WINDS AND 
SMALL HAIL. GIVEN THE WARM LAKE TEMPERATURES AND COLD AIR MASS 
ALOFT...CANNOT RULE OUT THE CHANCE FOR SOME WATERSPOUTS TONIGHT INTO 
EARLY WEDNESDAY ON LAKES ERIE AND ONTARIO. WATERSPOUTS FORM MAINLY 
IN AND NEAR SHOWERS AND AREAS OF TOWERING CUMULUS WHERE LOW LEVEL 
CONVERGENCE IS MAXIMIZED.

SMALL CRAFT CONDITIONS WILL PERSIST ON LAKE ERIE INTO THIS
EVENING AS A STIFF SOUTHWESTERLY FLOW REMAINS IN PLACE AHEAD OF A
SURFACE COLD FRONT. WINDS WILL TURN MORE NORTHWESTERLY AND WEAKEN 
THROUGH THE OVERNIGHT...ALLOWING CONDITIONS TO IMPROVE SOMEWHAT ON 
LAKE ERIE.

ON LAKE ONTARIO...STRONGER NORTHEASTERLY WINDS WILL PICK ON ON 
WEDNESDAY BEHIND THE SURFACE COLD FRONT...AND WILL EXCEED SMALL 
CRAFT CONDITIONS. THUS HAVE ISSUED A SMALL CRAFT ADVISORY FOR MUCH 
OF CENTRAL AND EASTERN PORTIONS OF LAKE ONTARIO FROM LATE WEDNESDAY 
MORNING THROUGH WEDNESDAY EVENING.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LEZ040-
         041.
         SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO MIDNIGHT 
         EDT WEDNESDAY NIGHT FOR LOZ043>045.

&&

$$

SYNOPSIS...CHURCH/HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...HITCHCOCK
MARINE...CHURCH



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