212 FXUS61 KBGM 221750 AFDBGM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 150 PM EDT THU AUG 22 2013 .SYNOPSIS... INCREASING MOISTURE AHEAD OF AN APPROACHING COLD FRONT, WILL TRIGGER A FEW SHOWERS AND THUNDERSTORMS, ACROSS NORTHEAST PENNSYLVANIA AND THE SOUTHERN CATSKILLS OF NEW YORK, EARLY THIS MORNING. THE COLD FRONT WILL BRING AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON AND EVENING, THEN HIGH PRESSURE WILL BRING A RETURN TO DRIER COOLER WEATHER FRIDAY THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... UPDATED AT 1030 AM... SHOWERS AND SCATTERED THUNDERSTORMS ASSOCIATED WTIH UPPER LEVEL LOW PRESSURE MOVING EAST ACROSS NORTHERN NJ LATE THIS MORNING. SOME ISOLATED SHOWERS AND STORMS MAY DEVELOP OVER NE PA MAINLY OVER HIGHER TERRAIN THIS AFTERNOON BUT ORGANIZED CONVECTION IS MOVING AWAY. MEANWHILE... THE MAIN TRIGGER FOR STORMS LATER TODAY WILL BE A COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT IS CURRENTLY JUST TO THE WEST OF TORONTO WITH LOTS OF CLEAR SKY AND DIURNAL HEATING DOWNSTREAM ACROSS NY STATE. OBSERVED 12Z BUF SOUNDING SHOWING POTENTIAL FOR 1800 J/KG OF CAPE THIS AFTERNOON AND LATEST 12Z NAM IS ALSO SHOWING MORE CAPE THAN PREVIOUS RUNS WITH VALUES INCREASING TO AROUND 1500 J/KG BY LATE AFTERNOON. HOWEVER A SIGNIFICANT LIMITING FACTOR FOR SEVERE WEATHER THIS AFTERNOON WILL CONTINUE TO BE WEAK DEEP LAYER WIND FIELDS AND SHEAR. 12Z BUF SOUNDING SHOWING 20-25 KTS OF LOW-LEVEL WIND WITH WEAKER WINDS ALOFT. 0-3 AND 0-6 KM SHEAR VALUES WILL BE 20-25 KTS ACROSS CENTRAL NY TODAY WHICH WILL BE MARGINAL FOR ANY SEVERE WX. SPC CONTINUES TO KEEP THE AREA IN SEE TEXT FOR MARGINAL SEVERE POTENTIAL. BASED ON ALL OF THIS EXPECT SHORT LINES OF STORMS TO DEVELOP LATER THIS AFTERNOON ACROSS CENTRAL NY MOVING TO NORTHEAST PA BY EARLY EVENING. A FEW STORMS MAY BECOME MARGINALLY SEVERE WITH GUSTY WINDS BUT A SIGNFICANT OUTBREAK IS NOT EXPECTED. PREVIOUS DISCUSSION BELOW. 3 AM UPDATE... SHOWERS AND THUNDERSTORMS CONTINUE OVER NE PA AND SULLIVAN COUNTY NY. EARLY THIS MORNING. FORCING CAUSED BY AN UPPER LEVEL LOW AND SHORT WAVE MOVING EAST WITH MOISTURE MOVG NE INTO THE AREA. BY 10 AM THIS FORCING WILL HAVE MOVED EAST AND THE CWA SHOULD BE DRY DURING THE MIDDAY WHILE WE WAIT FOR THE COLD FRONT TO GET CLOSER. EARLY THIS MORNING WITH ADDED LOW LEVEL MOISTURE IN THE FORM OF RAIN IN THE SOUTH SOME LIGHT FOG. IN THE SOUTHERN TIER SOME VALLEY FOG AGAIN BUT NOT AS MUCH AS THE LAST SEVERAL MORNINGS. MOST OF THE FOG WILL BE LIGHT AND 1 MILE OR MORE. WILL LEAVE FOG OUT OF THE WEATHER GRIDS. A COLD FRONT WILL MOVE SE THROUGH THE CWA THIS EVENING. THIS WILL PROVIDE SOME LIFT. DYNAMICS AND FORCING NOT IMPRESSIVE. SPC HAS THE ENTIRE AREA IN A SEE TEXT FOR DAMAGING WIND. CONTINUE TO MENTION THE LOW CHC OF A THUNDERSTORM WITH DAMAGING WIND IN THE HWO. MODEL SOUNDINGS SHOW LIGHT WINDS AND LITTLE SHEAR. ONLY 15 IN THE LOWEST KM AND 25 FOR LOWEST 6KM. LAPSE RATES NOT GREAT BUT WITH SOME SUNSHINE AND DEWPOINTS RISING INTO THE LOW AND MID 60S CAPE WILL APPROACH 1K. WITH LITTLE SHEAR SHOWERS AND TSTMS WILL FORM SHORT LINES. LATE TONIGHT SHOWERS MOVE OUT. LOW LEVEL FLOW FROM THE NW SO CLOUDS WILL HANG ON WITH THE LAKE ENHANCEMENT. WITH THE CLOUDS AND DRIER AIR SLOW TO MOVE IN MIN TEMPS WILL BE A60. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... 3 AM UPDATE... DRY FAIR WEATHER THIS PERIOD AS A LARGE SURFACE HIGH BUILDS SOUTHEAST TO BE CENTERED OVER THE CWA SATURDAY. EVEN WITH THE UPPER LEVEL TROF MOVING THROUGH FRIDAY WILL STILL HAVE SOME SUN AND NO SHOWERS. LOW LEVEL FLOW IS OUT OF THE NORTH SO A SHORT FETCH ACROSS LAKE ONTARIO. NO CONNECTION TO THE OTHER GREAT LAKES. 850MB TEMPS FALL TO 10C. FRIDAY NIGHT AND SAT BUILDING UPPER LEVEL HEIGHTS TOO. HIGH TEMPERATURES SLIGHTLY BELOW NORMAL BUT LOWS WILL BE IN LOW 50S AND UPPER 40S FRIDAY NIGHT THEN MOSTLY 40S SAT NGT WITH LIGHTER WINDS AND DRY AIR. && .LONG TERM /SUNDAY THROUGH THURSDAY/... 2 PM UPDATE... MODELS IN DISAGREEMENT REGARDING EXTNDD PATTERN. 00Z GFS MUCH STRONGER WITH UL RIDGE ACRS CNTRL U.S. AS OPPOSED TO 12Z EURO. THIS KEEPS A GOOD CHUNK OF PCPN OUT OF CWA THRU TUESDAY. EC BRINGS IN STRONG VORT MAX ON MONDAY WHILE GFS BRINGS SFC TROF THRU AREA MON NGT. BASED ON DISCREPANCIES HV INTRODUCED LOCHC POPS (20-30) STARTING SUN NGT AND CONTNG THRU THE END OF THE LONG TERM AS ANY LITTLE RIPPLE MVG THRU CUD RESULT IN SHOWERS/TSTMS. FOR NOW HV UPDATED WITH 00Z WPC GRIDS WITH TEMPS EXPECTED TO BE NEAR SEASONAL VALUES. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... 18Z UPDATE... VFR CU HAS POPPED ACROSS THE REGION AND A FEW TSTMS ARE DEVELOPING AHEAD OF A COLD FRONT ACROSS WESTERN NY AND ALONG A LAKE ONTARIO LAKE BOUNDARY. THE LAKE BOUNDARY LIES FROM N OF KRME TO N OF KSYR TO KROC. SHOWERS AND STORMS ALONG THIS ARE MOVING EAST ALONG THE BOUNDARY. STORMS ASSOCIATED WITH THE COLD FRONT WERE FROM W OF KROC SSW TO KPIT. THIS LINE WILL MOVE EAST AND IS TIMED WITH A TEMPO GROUP IN THE TAFS TO IMPACT KELM AND KSYR AFT 20Z...KBGM AND KAVP AFT 22Z. ISOLATED STORMS ARE POPPING UP AHEAD OF THIS LINE. GENERALLY MVFR CONDITIONS ARE EXPECTED WITH SHOWERS BUT BRIEF LOCAL IFR IS ALWAYS POSSIBLE WITH TSTMS. WINDS ARE WEST AT 10 KT. OVERNIGHT...BEHIND THE FRONT...CLOUDS WILL DIMINISH BUT LOW LEVEL MOISTURE WILL BE LEFT BEHIND AND SOME FOG FORMATION IS EXPECTED BY MORNING. OUTLOOK... FRI THROUGH MONDAY MORNING...MAINLY VFR. POSSIBLE IFR VALLEY FOG AT KELM ESPECIALLY SUNDAY/MONDAY MORNINGS. MONDAY AFTERNOON INTO TUESDAY...GENERALLY VFR. MVFR IN SHOWERS PSBL. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...TAC NEAR TERM...MSE/TAC SHORT TERM...TAC LONG TERM...BMW AVIATION...BMW