Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 250006 AFDBUF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 806 PM EDT FRI OCT 24 2014 .SYNOPSIS... HIGH PRESSURE OVER THE REGION THIS EVENING WILL DRIFT TO THE EAST COAST BY SATURDAY MORNING. A FAST MOVING COLD FRONT WILL CROSS THE AREA SATURDAY AFTERNOON WITH GUSTY WINDS AND A BRIEF PERIOD OF SCATTERED SHOWERS...WHICH WILL BE MOST NUMEROUS ACROSS THE NORTH COUNTRY. THE COLD FRONT WILL USHER IN A COOLER AIRMASS FOR SUNDAY BEFORE A SIGNIFICANT WARMING TREND ARRIVES FOR A FEW DAYS EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/...
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A NARROW SURFACE RIDGE WILL REMAIN OVER THE LOWER LAKES THIS EVENING. MICROWAVE SATELLITE IMAGERY THIS EVENING IS SHOWING AN AREA OF LOW CLOUDS ASSOCIATED WITH WARM AIR ADVECTION APPROACHING FROM SOUTHWEST ONTARIO PROVINCE. THIS WILL SPREAD EASTWARD AND INTO WESTERN NY AFTER 01Z AND CONTINUE EAST THROUGH THE OVERNIGHT WITH MOSTLY CLOUDY SKIES THEN FEATURED FOR THE REMAINDER OF THE NIGHT. LOW TEMPERATURES TONIGHT WILL BE ON THE MILD SIDE FOR LATE OCTOBER THANKS TO THE APPROACHING CLOUD COVER AND WARM AIR ADVECTION...WITH MID TO UPPER 40S ON THE LAKE PLAINS AND LOWER 40S IN THE COOLER MORE SHELTERED INTERIOR LOCATIONS. THE TUG HILL MAY DROP INTO THE UPPER 30S. SATURDAY MORNING THE AREA OF ISENTROPIC UPGLIDE AND ENHANCED LOW LEVEL MOISTURE WILL MOVE EAST AND QUICKLY WEAKEN...WHICH SHOULD ALLOW FOR AT LEAST PARTIAL CLEARING FOR A FEW HOURS DURING THE MID MORNING THROUGH EARLY AFTERNOON. DURING THE AFTERNOON A SHARP MID LEVEL TROUGH WILL DIG TOWARDS THE SAINT LAWRENCE VALLEY...WITH AN ASSOCIATED COLD FRONT PUSHING SOUTHEAST ACROSS THE REGION. THE STRONGEST LARGE SCALE ASCENT WILL CROSS THE NORTH COUNTRY DURING THE AFTERNOON WITH A PERIOD OF STRONG DPVA AHEAD OF THE SHORTWAVE AND UPPER LEVEL DIVERGENCE WITHIN THE LEFT EXIT REGION OF A 150+ KNOT UPPER LEVEL JET AND AREA OF DIFFLUENT FLOW ALOFT. PWAT VALUES RISE TO AROUND 1 INCH JUST AHEAD OF THE FRONT...MORE THAN AMPLE FOR LATE FALL. THIS SHOULD ALL COME TOGETHER WITH LOW LEVEL CONVERGENCE ALONG THE ADVANCING COLD FRONT TO PRODUCE A 2-3 HOUR PERIOD OF SHOWERS ACROSS THE NORTH COUNTRY. THE LIFTED INDEX DROPS TO -1C TO -3C DEPENDING ON MODEL OF CHOICE ACROSS THE NORTH COUNTRY...AND THIS MARGINAL INSTABILITY COMBINED WITH STRONG FORCING MAY PRODUCE A FEW SCATTERED WEAK THUNDERSTORMS AS WELL. FARTHER SOUTHWEST ALONG THE TRAILING COLD FRONT LARGE SCALE ASCENT WILL BE MUCH WEAKER...SO EXPECT SHOWERS TO REMAIN WIDELY SCATTERED ACROSS THE REST OF THE AREA DURING THE MID TO LATE AFTERNOON. CLOUDS WILL INCREASE ONCE AGAIN DURING THE AFTERNOON ALONG AND BEHIND THE SURFACE COLD FRONT AS MOISTURE BECOMES TRAPPED BENEATH THE FRONTAL INVERSION. A BRIEF WINDOW OF 850MB TEMPS AROUND +7C JUST AHEAD OF THE COLD FRONT WILL SUPPORT ABOVE AVERAGE HIGHS...IN THE MID 60S AT LOWER ELEVATIONS AND UPPER 50S ACROSS HIGHER TERRAIN. SOME OF THE WARMER SPOTS IN THE GENESEE VALLEY AND NORTHERN FINGER LAKES MAY REACH THE UPPER 60S. IT WILL BECOME QUITE WINDY ON SATURDAY...ESPECIALLY NORTHEAST OF LAKE ERIE IN A CORRIDOR FROM THE NIAGARA FRONTIER TO ROCHESTER WHERE BUFKIT MOMENTUM TRANSFER SCHEMES SUGGEST GUSTS IN THE 35-40 MPH RANGE DURING THE AFTERNOON.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH TUESDAY NIGHT/... WATER VAPOR IMAGERY THIS AFTERNOON DISPLAYS TWO SHORTWAVES...A COMPACT SHORTWAVE JUST TO THE NORTHWEST OF LAKE WINNIPEG...AND A SECOND MORE BROAD WAVE JUST OFF THE NORTHERN CALIFORNIA COASTLINE. THESE TWO FEATURES WILL BE KEY OVER THIS UPCOMING TIMEFRAME. THE FIRST SHORTWAVE WILL PUSH A COLD FRONT ACROSS OUR REGION SATURDAY...WITH THE FRONT JUST TO THE EAST OF THE CWA BY THE SATURDAY EVENING...THE START OF THIS TIME PERIOD. ALOFT THE SHORTWAVE WILL LAG BEHIND THE FRONT WITH THE WAVE STILL CROSSING SOUTHEASTWARD FROM THE UPPER LAKES TO NEW YORK AND NEW ENGLAND. ANY RAIN SHOWERS ACROSS THE SOUTHERN GENESEE VALLEY WILL END EARLY SATURDAY EVENING...THOUGH ACROSS THE EASTERN LAKE ONTARIO REGION...AND UNDER THE UPPER LEVEL SHORTWAVE SCATTERED RAIN SHOWERS WILL LINGER THROUGH MUCH OF SATURDAY NIGHT. BEHIND THE COLD FRONT TEMPERATURES AT 850 HPA WILL DROP TO AROUND -1C OVER LAKE ONTARIO...AND SLIGHTLY WARMER OVER LAKE ERIE. THE LAKE INDUCED EQUILIBRIUM LEVELS WILL BE UP TO 10-12K FEET AND THERE WILL ALSO BE LITTLE WIND SHEAR. THESE FACTORS...ALONG WITH LOW LEVEL CONVERGENCE WILL AID TO DEVELOP A BAND OF LAKE EFFECT RAIN OVERNIGHT SOUTHEAST OF LAKE ONTARIO WHERE GREATER AMBIENT SYNOPTIC MOISTURE RESIDES. AS LAKE PARAMETERS BECOME POORER THROUGH THE DAY ON SUNDAY AND COMBINED WITH DAYTIME HEATING THE BAND OF RAIN OFF LAKE ONTARIO WILL FALL APART THROUGH THE DAYTIME SUNDAY. SOUTH OF LAKE ONTARIO THERE SHOULD BE A FAIR AMOUNT OF SUNSHINE THROUGH THE DAY AS HIGH PRESSURE BUILDS EASTWARD FROM THE MIDWEST. THE CORE OF THE HIGH PRESSURE WILL PASS ACROSS OUR REGION LATE SUNDAY NIGHT THROUGH MONDAY MORNING. THIS WILL PROVIDE FOR QUIET AND DRY CONDITIONS. LATER MONDAY MOISTURE WILL BEGIN TO BUILD NORTHWARD AS SOUTHERLY FLOW INCREASES. A WARM FRONT LIFTING NORTHWARD INTO THE CENTRAL GREAT LAKES REGION MAY BRING A SHOWER FAR ENOUGH EASTWARD TO BRUSH BY FAR WESTERN NEW YORK THROUGH THE DAY. MONDAY NIGHT THE PACIFIC SHORTWAVE WILL NOW BE JUST TO THE EAST OF THE ROCKIES WHERE IT WILL CARRY AND DEEPEN AN AREA OF LOW PRESSURE FROM NEAR IOWA MONDAY EVENING TO THE WESTERN GREAT LAKES BY TUESDAY MORNING. A WARM FRONT STRENGTHENING ON THIS DEEPENING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTHWARD ACROSS THE CENTRAL GREAT LAKES...AND LAKE ONTARIO REGION. A FEW SHOWERS WILL BE POSSIBLE MONDAY NIGHT ACROSS LAKE ONTARIO AND AREAS JUST TO THE EAST AS THE WARM FRONT LIFTS NORTHWARD THROUGH OUR REGION. AFTER THIS WARM FRONT PASSES...AND WITH DAYTIME MIXING THE FIRST HALF OF TUESDAY WILL LIKELY FEATURE DRY CONDITIONS. HOWEVER THE SURFACE LOW TO OUR WEST WILL BE PUSHING A COLD FRONT...ACCOMPANIED BY SHOWERS INTO WESTERN NEW YORK BY THE END OF THE DAY TUESDAY. HIGH CHANCES POPS WILL CONTINUE FOR TUESDAY AFTERNOON THROUGH THE NIGHT AS THE COLD FRONT AND SHOWERS PASS ACROSS THE REGION FROM WEST TO EAST. BEHIND THIS COLD FRONT...AND AS THE COLD AIR DEEPENS A FEW LAKE EFFECT RAIN SHOWERS WILL BE POSSIBLE LATE TUESDAY NIGHT...AND MAINLY EAST OF LAKE ONTARIO ON A WESTERLY FLOW. TEMPERATURES WILL START AROUND NORMAL...TO SLIGHTLY COOLER THAN NORMAL THIS TIME PERIOD...AND THEN GRADUALLY WARM UNTIL THE COLD FRONT PASSAGE. FOR SATURDAY NIGHT LOWS WILL GENERALLY RANGE THROUGH THE 40S...WITH WARMEST AREAS UNDER LAKE EFFECT CLOUDS SE OF LAKE ONTARIO. SUNDAY...BEHIND THE COLD FRONT WILL BE COOLER THAN SATURDAY WITH HIGHS RIGHT AROUND NORMAL...AND THAT AT LOW TO MID 50S. AS HIGH PRESSURE DROPS ACROSS THE REGION AND SKIES CLEAR...SUNDAY NIGHT WILL BE CHILLY WITH LOWS IN THE LOW TO MID 30S. AGAIN WARMEST AREAS WILL LIKELY BE SE OF LAKE ONTARIO WHERE SOME LINGER LOW CLOUDS WILL RESIDE. GRADUALLY WARMING MONDAY AND TUESDAY...SUCH THAT THERE MAY BE A FEW 70S TUESDAY AFTERNOON. WITH THE MODELS QUICKER WITH THE COLD FRONT AND PRECIPITATION...NEAR RECORD WARMTH SEEMS LESS LIKELY NOW. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... SHORTWAVE PASSING NORTH OF THE FORECAST AREA WILL PUSH A COLD FRONT THROUGH TUESDAY NIGHT...WITH CONTINUED COLD AIR ADVECTION THROUGH THE DAY ON WEDNESDAY. HIGH TEMPERATURES WILL RUN ABOUT 10 TO 15 DEGREES COOLER ON WEDNESDAY THAN TUESDAY...WITH MID 50S COMMON. UNIDIRECTIONAL SOUTHWESTERLY LOW-LEVEL FLOW BEHIND THE FRONT...ALONG WITH CONTINUED COLD AIR ADVECTION WILL SUPPORT A WINDIER DAY ON WEDNESDAY. MAINLY DRY CONDITIONS EXPECTED IN THE POST-FRONTAL ENVIRONMENT WEDNESDAY INTO THURSDAY. THE EXCEPTION IS A CHANCE FOR SOME LAKE INDUCED RAIN SHOWERS EAST OF LAKE ONTARIO...AND SOUTH OF BUFFALO TOWARD JAMESTOWN. FORECAST SOUNDINGS SUGGEST A SHALLOW LAYER OF INSTABILITY...WITH LAKE INDUCED EQUILIBRIUM LEVELS ONLY AROUND 5K FEET. THUS FORECAST CONFIDENCE IN INTENSITY AND COVERAGE IS LOW...AND HAVE LEFT ONLY SLIGHT CHANCE TO CHANCE POPS IN THE FORECAST THROUGH THE PERIOD. THE SURFACE PRESSURE GRADIENT ACROSS THE FORECAST AREA WILL WEAKEN WEDNESDAY NIGHT INTO THURSDAY AS THE SURFACE LOW NEAR THE HUDSON BAY SHIFTS NORTH AND EASTWARD. WINDS WILL DECREASE AND SHIFT TO THE WEST AND NORTHWEST FOR THURSDAY. ANOTHER WEAK DISTURBANCE WILL APPROACH THE AREA ON FRIDAY WHICH SHOULD PUSH TEMPERATURE SLIGHTLY BELOW NORMAL AND BRING A CHANCE FOR SOME SCATTERED RAIN SHOWERS ACROSS THE FORECAST AREA. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
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VFR WILL PREVAIL THROUGH MUCH OF THE OVERNIGHT. SATELLITE IMAGERY THIS EVENING IS SHOWING AN AREA OF LOW CLOUDS APPROACHING FROM SOUTHWEST ONTARIO. THIS WILL SPREAD EAST ACROSS WNY THE AREA AFTER 01Z EVENTUALLY REACHING ART/CNY BY 09Z. ACROSS FAR WNY GUIDANCE SUGGESTS THAT CIGS AT KBUF/KROC/KJHW WILL DROP TO MVFR AFTER 10Z AND AT KART AFTER 12Z. DURING THE AFTERNOON A COLD FRONT AND POTENT MID LEVEL DISTURBANCE WILL CROSS THE REGION. THIS WILL PRODUCE A FEW SCATTERED SHOWERS IN MOST AREAS...WITH SHOWERS MORE LIKELY ACROSS THE NORTH COUNTRY. A FEW SCATTERED THUNDERSTORMS ARE ALSO POSSIBLE ACROSS THE NORTH COUNTRY. THESE SHOWERS WILL HELP CIGS REBOUND TO VFR...BUT A PERIOD OF MVFR OR EVEN IFR CIGS MAY BE POSSIBLE FOR A FEW HOURS IMMEDIATELY BEHIND THE COLD FRONT DURING THE LATE AFTERNOON. VSBY SHOULD STAY MAINLY VFR FOR MOST OF THE AREA WITH SHOWERS LIGHT AND SCATTERED IN NATURE. THE NORTH COUNTRY MAY SEE A BRIEF PERIOD OF MVFR/IFR VSBY IN ANY HEAVIER AND MORE CONCENTRATED SHOWERS. OUTLOOK... SUNDAY...MAINLY VFR...EXCEPT AREAS OF MVFR EAST AND SOUTHEAST OF LAKE ONTARIO WITH SHOWERS LIKELY. MONDAY...MAINLY VFR. TUESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS. WEDNESDAY...MAINLY VFR EXCEPT MVFR WITH A CHANCE OF SHOWERS EAST OF THE LAKES.
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&& .MARINE...
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WESTERLY WINDS REMAIN ELEVATED AT 15-20 KNOTS ON THE EASTERN PORTION OF BOTH LAKES ONTARIO AND ERIE. THESE CONDITIONS ON LAKE ONTARIO WILL BE SHORT LIVED WITH WINDS AND WAVES COMING BACK DOWN BY 11PM THIS EVENING. ON LAKE ERIE CHOPPY CONDITIONS WILL PERSIST THROUGH THE NIGHT WITH WINDS AND WAVES AT SMALL CRAFT ADVISORY LEVELS. A MODERATELY STRONG AREA OF LOW PRESSURE WILL MOVE ACROSS NORTHERN ONTARIO AND QUEBEC ON SATURDAY...WITH A TRAILING COLD FRONT CROSSING THE LOWER LAKES DURING THE AFTERNOON. SOUTHWEST WINDS WILL INCREASE INTO THE 20-25 KNOT RANGE ON BOTH LAKES AHEAD OF THE COLD FRONT... THEN BECOME WEST SATURDAY NIGHT AND SUNDAY. WINDS MAY INCREASE FURTHER TO 30 KNOTS ON LAKE ONTARIO DURING THAT TIME FRAME AS COLD AIR DEEPENS AND PROMOTES STEEP LOW LEVEL LAPSE RATES AND STRONG MIXING. THIS WILL SUPPORT A PERIOD OF HIGH END SMALL CRAFT ADVISORY CONDITIONS THROUGH THE ENTIRE WEEKEND. HIGH PRESSURE WILL BUILD OVER THE LOWER LAKES BY MONDAY AND BRING AN END TO SMALL CRAFT ADVISORY CONDITIONS.
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&& .BUF WATCHES/WARNINGS/ADVISORIES...
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NY...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR LEZ040-041. SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EDT SATURDAY FOR LEZ020. SMALL CRAFT ADVISORY FROM 4 PM SATURDAY TO 8 AM EDT MONDAY FOR LOZ043>045. SMALL CRAFT ADVISORY FROM 1 PM SATURDAY TO 5 AM EDT MONDAY FOR LOZ042. SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LOZ044-045.
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&& $$ SYNOPSIS...HITCHCOCK NEAR TERM...HITCHCOCK/SMITH SHORT TERM...THOMAS LONG TERM...CHURCH AVIATION...HITCHCOCK/SMITH MARINE...HITCHCOCK/SMITH

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