000 FXUS61 KBTV 231453 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 952 AM EST MON NOV 23 2009 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH TODAY AND THIS EVENING. A LOW MOVING UP THE COAST WILL AFFECT CENTRAL AND SOUTHERN NEW ENGLAND LATE TONIGHT INTO TUESDAY...FOLLOWED BY ANOTHER AREA OF HIGH PRESSURE WEDNESDAY. A BROAD AREA OF LOW PRESSURE WILL AFFECT THE REGION LATE THURSDAY ON INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 952 AM EST MONDAY...QUICK UPDATE TO FIRST TWO PERIODS OF THE FCST...MAINLY TO REFLECT LATEST TRENDS IN SKY COVER...AND TO KEEP ANY PCPN LATER TONIGHT IN LIQUID FORM. LATEST ANALYSIS SHOWING LIGHT SOUTH TO SOUTHEASTERLY FLOW HAS BECOME ESTABLISHED IN MOST AREAS THIS MORNING AS MEAN SFC RIDGING CONTINUES TO SLIDE SLOWLY EASTWARD. THIS HAS ALLOWED MOIST LOW LVL CLOUDINESS OF MARITIME ORIGIN TO CREEP NORTHWARD...ESP ACROSS OUR ERN VT COUNTIES. WITH PRONOUNCED SUBSIDENCE INVERSION REMAINING IN PLACE EXPECT THIS ACTIVITY TO ESSENTIALLY HOLD IN PLACE THROUGH MID AFTERNOON...THEN CREEP STEADILY NORTHWARD BY THIS EVENING AS SOUTHERLY FLOW STRENGTHENS SLIGHTLY ALOFT. BASED OFF EXPECTED CLOUD COVER AND MARINE-MODIFIED AIRMASS ATOP THE AREA TONIGHT...BELIEVE MIN TEMPS SHOULD STAY ABOVE FREEZING IN MOST AREAS...ESP SOUTH. THUS ANY PCPN THAT MAY OCCUR WITH OFFSHORE COASTAL SYSTEM ACROSS OUR SRN COUNTIES WOULD BE LIGHT AND IN THE LIQUID FORM. REST OF FCST IN GOOD SHAPE AND OTHER THAN CHGS NOTED ABOVE...NO OTHER ADJUSTMENTS NEEDED ATTM. ENJOY THE DAY. PREVIOUS DISCUSSION FROM 310 AM EST MONDAY... SFC RIDGE CENTERED TO OUR NORTH OVER N MAINE/CANADIAN MARITIMES HAS SET UP EASTERLY FLOW FOR GD PORTION OF NEW ENG REGION. THIS HAS ALLOWED LL CLD DECK TO PUSH WESTWARD INTO THE CWA AS EVIDENT BY LATEST IR SAT PIC. EXPECTING THIS CLD COVER TO OVERSPREAD MUCH OF E VT DURING THE DAY AND EVEN FILTER DOWN INTO THE CVLY AND PORTIONS OF N NY. FAIRLY NICE DAY OVERALL ON TAP...W/ EXCEPTION BEING BLW NORMAL TEMPS IN AREAS SEEING LOW CLD SHIELD...ESPECIALLY IN E VT. GOING INTO THE EVENING HRS...RIDGE TO OUR N AND E SLIDES FURTHER OFFSHORE...ALLOWING CWA TO REMAIN UNDER SOUTHERLY WIND REGIME. CLDS ON THE INCR FOR CENTRAL/SOUTHERN AREAS GOING INTO OVERNGT HRS AS SFC LOW WORKS N ALONG THE COAST. MDLS A BIT DISCREPANT AS TO THE NORTHWARD PUSH OF PRECIP/CLDS INTO THE AREA BFR MVG E OUT TO SEA. W/ EFFECTS OF BLOCKING RIDGE STILL EVIDENT OVER PORTIONS OF THE NORTHEAST...WILL CONTINUE TREND OF KEEPING BULK PRECIP OVER SC VT...AND A SL CHANCE FOR CENTRAL AREAS FOR PRECIP. SOME CD AIR INITIALLY AS A RESULT OF CLR SKIES IN SOME AREAS WILL ALLOW FOR TEMPS TO DROP SOME BFR ARRIVAL OF PRECIP...SO WILL MENTION A FEW HRS WHERE --SW TO MIX W/RAIN SHOWERS(WHICH WILL BE PREDOMINATE WX TYPE). && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 310 AM EST MONDAY...SFC LOW MVS OFFSHORE SLOWLY BY TUESDAY MORNING. ENE FLOW OVER THE REGION AS SFC RIDGE BEGINS TO BUILD BACK DOWN OVER THE NORTH COUNTRY. WITH EASTERLY FETCH STILL EXPECT CLD COVER TO REMAIN AS LOW EXITS...SO WILL CONTINUE MENTION OF -RW THRU MIDDAY AND BECM CLR BY THE EVNEING HRS. RIDGE WILL REMAIN IN PLACE GOING INTO WEDNESDAY AS NEXT SYSTEM APPROACHES FROM THE GREAT LKS REGION. MDLS HAVE TRENDED SLOWER ON APPROACH OF THIS NEXT SYSTEM DUE TO RIDGE PLACEMENT. HAVE KEPT MUCH OF THE CWA DRY WITH EXCEPTION BEING SLV AND WESTERN PORTIONS OF DACKS...ALTHOUGH GD PORTION OF CWA WILL SEE INCR IN MID/HIGH CLDS DURING THE DAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 352 AM EST MONDAY...THE AFOREMENTIONED FRONT LOOKS TO WEAKEN BEFORE IT MOVES INTO THE NORTH COUNTRY WEDNESDAY NIGHT THURS MORNING...WITH MAJORITY OF LIFT AND MOISTURE REMAINING WELL TO OUR SOUTH. SO I`VE MAINTAINED ONLY A CHANCE OF MEASURABLE PRECIPITATION ACROSS THE FORECAST AREA WED NIGHT. FOR THURSDAY....THERE ARE STILL SOME TIMING ISSUES WITH THE EASTWARD PROGRESSION OF THE STRONG SHORTWAVE...AND NORTHWARD PROGRESSION OF LOW DEVELOPING OFF CAROLINA COAST. LATEST GUIDANCE SLOWS THINGS DOWN...GIVING THE WEST AND SOUTHERN PORTION OF OUR AREA BEST PROBABILITIES OF SEEING PRECIPITATION ON THANKSGIVING. ONE THING THAT IS CONSISTENT IS THE SOUTH TO SOUTHWEST FLOW OVER NEW ENGLAND WHICH KEEPS TEMPS WELL ABOVE SEASONAL NORMS THURSDAY...AND THUS ANY PRECIPITATION SHOULD REMAIN ALL RAIN FOR THE HOLIDAY. BY THURSDAY NIGHT THE COASTAL LOW SHOULD BE SOMEWHERE NEAR LONG ISLAND OR THE BENCH MARK...WITH A FRONT EXTENDING BACK INTO ONTARIO. AT THIS TIME WE INCREASE POTENTIAL FOR PRECIPITATION ACROSS THE WHOLE REGION...ESPECIALLY POINTS WEST AND SOUTH...SPREADING EAST THROUGH FRIDAY. THE TIMING OF THE COLD AIR...AND CONSEQUENTLY CHANGE FROM RAIN TO SNOW...IS VERY MUCH DEPENDENT ON THE POSITION OF THE SFC LOW. THE PREFERRED ECMWF GUIDANCE INDICATES THAT THE LOW WILL HUG THE NEW ENGLAND COASTLINE WITH A POSITION NEAR DOWNEAST MAINE FRIDAY AFTERNOON. THIS WILL ALLOW COLD AIR TO MOVE INTO THE REGION LATE FRIDAY...WITH RAIN CHANGING TO SNOW AT HIGHER ELEVATIONS FRIDAY AFTERNOON/EARLY EVENING...AND MIXING WITH OR CHANGING TO SNOW IN THE VALLEYS FRIDAY NIGHT. THE SYSTEM BEGINS TO EXIT THE AREA SATURDAY...BUT WE REMAIN UNDER THE BROAD UPPER TROUGH AND UNDER N TO NW FLOW THROUGH SATURDAY. THESE FAVORABLE UPSLOPE CONDITIONS MEAN THE POTENTIAL FOR SNOW SHOWERS CONTINUES SATURDAY....ESPECIALLY IN HIGHER ELEVATIONS AND POINTS JUST WEST OF THE GREEN MTNS. AS THE BROAD TROUGH MOVES EAST AND FLOW BECOMES MORE WESTERLY BY SUNDAY...WE SHOULD SEE SHOWERS TAPERING OFF. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... THROUGH 12Z TUESDAY...AN INVERSION ONCE AGAIN KEEPS MOISTURE TRAPPED AT LOW LEVELS AT MOST LOCATOINS. BR AND OR MVFR STRATUS REMAIN AT KMPV...KRUT...KMSS...AT THIS HOUR...WITH FLIGHT CATEGORIES RAISING TO VFR AFTER 16Z. KBTV IS SKC WITH A BIT IF MIST IN THE AIR. KPBG HAS IFR CEILINGS DUE TO LAKE STRATUS... THIS WILL LIFT TO MVFR BY 14Z AND VFR BY 16Z. KSLK IS LIFR IN FG...AND WILL SLOWLY RAISE TO VFR BY 16Z. WINDS ARE GENERALLY SSE 5-10 KT TODAY...AND WILL DIMINISH TO LIGHT AND VAR TONIGHT. IN S AND E VT INCREASED MOISTURE FROM A COASTAL LOW MEANS SKIES WILL NOT CLEAR. THE GREENS WILL BE OBSCURED IN CLDS AND CLOUDS WILL LOWER TO MVFR BY 00Z AT KMPV...KRUT...AND EVEN IN KSLK. VERY LIGHT RAIN IS POSSIBLE IN KRUT AFTER MIDNIGHT. THIS INCREASED MOISTURE...AND RETURN OF NOCTURNAL INVERSION...WILL ALSO LOWER CIGS TO MVFR IN KBTV AND KPGB AFTER MIDNIGHT. OUTLOOK 12Z TUESDAY THROUGH FRIDAY... TUESDAY THROUGH WEDNESDAY...MVFR TUE MORNING BECOMING VFR IN THE AFTERNOON. INCREASING CLOUDS WEDNESDAY EVENING. WEDNESDAY NIGHT THROUGH THURSDAY...VFR/MVFR IN RAIN SHOWERS AS A WEAK FRONT APPROACHES FROM THE GREAT LAKES. THURSDAY NIGHT THROUGH FRIDAY...MVFR/IFR IN OCCASIONALLY HEAVY RAIN AS LOW PRESSURE MOVES ACROSS THE AREA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JN NEAR TERM...JMG/JN SHORT TERM...JN LONG TERM...AMF AVIATION...AMF/MB