342 FXUS61 KBTV 202354 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 754 PM EDT MON MAY 20 2013 .SYNOPSIS... UNSETTLED WEATHER PATTERN IS EXPECTED...AS A FRONTAL BOUNDARY AMBLES ABOUT THE NORTH EAST....RESULTING IN SEVERAL ROUNDS OF RAIN SHOWERS AND THUNDERSTORMS INTO THE MIDDLE OF THIS WEEK. HIGH PRESSURE AND DRIER CONDITIONS RETURN FRIDAY AND CONTINUE INTO THE WEEKEND...WITH COOLER TEMPERATURES ABOUT 5 DEGREES BELOW NORMAL. && .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/... AS OF 702 PM EDT MONDAY...WITH SKIES BEGINNING TO CLEAR OUT HAVE REMOVED MENTION OF SLIGHT CHANCE OF SHOWERS FOR A DRY FORECAST THROUGH MIDNIGHT. WILL BE WATCHING ONGOING THUNDERSTORM CLUSTER ACROSS THE NORTHERN GREAT LAKES FOR POTENTIAL THAT THEY MAY SPREAD INTO PARTS OF NORTHERN NEW YORK AFTER MIDNIGHT. THE NORTH COUNTRY IS ON THE EXTREME NORTHERN EDGE OF BETTER INSTABILITY CENTERED OVER SOUTHWESTERN NEW YORK AND THE OHIO VALLEY. SHOWALTER INDICES ARE PROJECTED TO DROP BELOW ZERO ACROSS THE ADIRONDACKS INTO SOUTHERN VERMONT OVERNIGHT WHICH OFFERS SOME POTENTIAL FOR THUNDER IN THESE AREAS. HAVEN'T MENTIONED THUNDER IN THE CURRENT FORECAST BUT WILL MONITOR TRENDS CLOSELY THIS EVENING. OTHERWISE...HAVE JUST MATCHED WITH CURRENT OBSERVATIONAL DATA AS REMAINDER OF FORECAST IN GOOD SHAPE. && .SHORT TERM /8 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 355 PM EDT MONDAY...STALLED FRONTAL BOUNDARY REMAINS OVER THE NORTH COUNTRY DURING THE SHORT TERM PERIOD AND WILL BE THE FOCUS FOR PERIODS OF RAIN AND POSSIBLE THUNDERSTORMS THROUGH WEDNESDAY. RAIN SHOWERS SPREAD EWD TUESDAY MORNING WITH CLOUDY SKIES AND SOUTHERLY WINDS. GFS BEING THE OUTLIER TAKES THE BOUNDARY TO OUR SOUTH TUESDAY AFTN...WITH MOST GUIDANCE KEEPING IT OVER THE NORTH COUNTRY. 925MB TEMPS DEPICT THE BOUNDARY OVER THE AREA WELL...WITH COOLER TEMPS OVER THE NEK TUESDAY AND MOST OF THE AREA SEEING 925MB TEMPS IN THE LOW TO MID TEENS. CLOUDS CONTINUE OVER THE AREA WITH RAIN SHOWERS AND EVEN LIFTED INDICES OF -2 FOR AT LEAST NRN NY AND SRN HALF OF VT. SOME CAPE AND TEMP LAPSE RATES OF 6-7 C/KM COULD HELP TRIGGER A FEW TS TUESDAY AFTN. MOISTURE CONTINUES TO STREAM IN TO THE NORTH COUNTRY WITH GEFS SHOWING PWATS OF 1 TO 3 STANDARD DEVIATIONS ABOVE NORMAL THROUGHOUT THE PERIOD. TUESDAY NIGHT...WELL DEPICTED WARM FRONT LIFTING NORTH AS WE CONTINUE TO BE IN THE WARM SECTOR AND 925MB TEMPS INCREASE TO UPPER TEENS...POSSIBLY LOW 20S ON WEDNESDAY. SFC LOW MOVES INTO SERN ONTARIO...RESULTING IN SW FLOW...BRINGING IN MORE INSTABILITY ON WEDNESDAY. BEST CHANCES FOR TS WILL BE ON WEDNESDAY AS LIFTED INDICES OF ZERO TO -4 SPREAD OVER THE ENTIRE NORTH COUNTRY. TEMP LAPSE RATES GREATER THAN 7C/KM WILL ALSO MOVE INTO THE AREA. SOME SHOWERS AND STORMS WILL LINGER INTO WEDNESDAY NIGHT AS LOW LEVEL SW JET INCREASES IN STRENGTH AT 30-40 KTS. TEMPS THROUGHOUT THE PERIOD WILL BE ABOVE NORMAL IN THE 70S TUESDAY AND NEARING 80 ON WEDNESDAY. OVERNIGHT LOWS WILL BE MILD DUE TO CLOUDS...IN THE 50S AND LOW 60S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 425 PM EDT MONDAY... A COLD FRONT WITH SHOWERS AND THUNDERSTORMS ON THURSDAY WILL USHER IN COOLER AND MAINLY DRY WEATHER FOR THE UPCOMING MEMORIAL DAY WEEKEND. CONFIDENCE FAIRLY HIGH IN THE LARGE-SCALE FEATURES AS UPPER TROF PASSES SLOWLY ACROSS THE REGION. SOME UNCERTAINTY IN HOW THE TROF EVOLVES AND HOW FAST IT MOVES OUT TOWARD THE END OF THE PERIOD. ON THURSDAY THE COLD FRONT WILL MOVE SLOWLY SOUTHEAST THROUGH THE AREA. INSTABILITY EXPECTED TO BE MARGINAL WITH CAPE VALUES AROUND 500 J/KG OR SO AND WILL DEPEND UPON CLOUD COVER. WITH LESS CLOUD COVER VALUES COULD CLIMB NEAR 1000 J/KG ESPECIALLY SOUTH AND EAST OF BTV. IF THE INSTABILITY MATERIALIZES AND 0-6KM BULK SHEAR VALUES OF 30-40 KTS WILL HAVE TO WATCH FOR A FEW STRONGER STORMS. HIGHS SHOULD BE IN THE 70S WITH 850 TEMPS AROUND +12C. THURSDAY NIGHT WILL FEATURE A TRANSITION TO MUCH COOLER TEMPS WITH 850 TEMPS FALLING TO NEAR 0C BY 12Z FRIDAY. COULD BE SOME LINGERING SHOWERS OVER NIGHT. A COOL NW FLOW ON FRIDAY AND SATURDAY WITH 850 TEMPS AROUND 0 WILL KEEP HIGH TEMPERATURES IN THE UPPER 50S TO MID 60S WITH PLENTY OF CUMULUS CLOUDS AND EVEN A CHANCE OF A SHOWER DURING THE AFTERNOON OR EVENING HOURS ESPECIALLY IN THE MOUNTAINS. LOW TEMPERATURES WILL BE MAINLY 35 TO 45. SUNDAY AND MONDAY SHOULD BE DRY AS HIGH PRESSURE MOVES INTO THE NORTHEAST AND TEMPERATURE WILL BEGIN TO RETURN TO NORMAL WITH HIGHS IN THE UPPER 60S TO LOW 70S AND LOWS IN THE 40S. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THROUGH 00Z WEDNESDAY...LOW LEVEL MOISTURE REMAINS OVER THE AREA AND THIS SHOULD LEAD TO A TREND FROM VFR CEILINGS AND VISIBILITIES TO MVFR/IFR CEILINGS/VISIBILITIES BETWEEN 04Z AND 14Z. RAIN SHOWERS WILL MOVE INTO SOUTHERN QUEBEC PROVINCE LATER TONIGHT AND DROP INTO NORTHERN NEW YORK AND NORTHERN VERMONT AFTER 08Z. THE THREAT FOR SHOWERS WILL CONTINUE THROUGHOUT THE MORNING AND AFTERNOON HOURS ON TUESDAY. WINDS WILL BE VARIABLE UNDER 10 KNOTS. OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY... TUE PM...WARM FRONT BRINGS MVFR SHOWERS WITH EMBEDDED TSTMS WITH BRIEF IFR. WED- THU...SHOWERS/THUNDERSTORMS WITH PERIODS OF MVFR CONDITIONS. THU NIGHT INTO FRI/SAT...MAINLY VFR AS DRY NWLY WINDS DEVELOP. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...KGM NEAR TERM...KGM/LOCONTO SHORT TERM...KGM LONG TERM...SISSON AVIATION...EVENSON/SISSON