Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 242341 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 741 PM EDT THU JUL 24 2014 .SYNOPSIS... DRY WEATHER IS EXPECTED RIGHT THROUGH SATURDAY AS HIGH PRESSURE BUILDS DOWN FROM CANADA. HIGH TEMPERATURES WILL BE JUST BELOW SEASONAL NORMALS ON FRIDAY AND THEN RIGHT AROUND SEASONAL NORMAL SATURDAY. A CHANCE WILL TAKE PLACE SATURDAY NIGHT INTO SUNDAY AS AN UPPER LEVEL TROUGH OF LOW PRESSURE MOVES INTO THE REGION AND ENHANCES THE POTENTIAL FOR SHOWERS AND A FEW THUNDERSTORMS. && .NEAR TERM /UNTIL 8 AM FRIDAY MORNING/... AS OF 728 PM EDT THURSDAY...GOING FORECAST IN GOOD SHAPE. HIGH PRESSURE BUILDING INTO THE REGION WILL PROVIDE FOR MOSTLY CLEAR SKIES AND A COOL NIGHT. A FEW CLOUDS MAY SKIRT THE INTERNATIONAL BORDER AS THEY PINWHEEL AROUND THE UPPER TROUGH TO THE NORTH. LOWS 45-55F STILL LOOK GOOD. PATCHY FOG IS ALSO POSSIBLE IN THE FAVORED VALLEYS GIVEN MOSTLY CLEAR SKIES AND RECENT RAINFALL. NOT EXPECTING WIDESPREAD FOG THOUGH WITH SIGNIFICANT DRYING OF THE LOW LEVELS DURING THE DAY AND 10-15 KNOT WINDS STILL LINGERING IN THE LOWER 1000 FEET OF THE ATMOSPHERE. PREVIOUS DISCUSSION FROM 339 PM THURSDAY... DIURNALLY DRIVEN CUMULUS OVER THE MOUNTAINS WILL CONTINUE TO DECREASE THIS AFTERNOON AND SHOULD MAINLY BE GONE BY SUNSET. DRIER AIR IS ALSO MOVING INTO THE REGION ON NORTHWEST FLOW ALOFT...WHICH SHOULD ALLOW FOR BELOW NORMAL TEMPERATURES TONIGHT WITH LOWS IN THE MID 40S TO MID 50S. BULK OF THE SMOKE THAT HAS GOTTEN PICKED UP IN THE NORTHWEST FLOW ALOFT SHOULD PASS TO OUR SOUTHWEST...BUT STILL SOME OVER QUEBEC THAT COULD MAKE IT INTO THE REGION. && .SHORT TERM /8 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... AS OF 339 PM EDT THURSDAY...THE COMBINATION OF A RELATIVELY DRY AIR MASS AND LIMITED FORCING SUGGESTS ANOTHER DRY DAY IS IN STORE FOR THE AREA ON FRIDAY. THERE SHOULD BE SHALLOW CUMULUS FORMING OVER THE MOUNTAINS ONCE AGAIN...BUT VERTICAL DEPTH SHOULD BE LIMITED AND NOT BE ABLE TO PRODUCE ANY PRECIPITATION. WE SHOULD SEE WARMER TEMPERATURES THAN THURSDAY...BUT HIGHS WILL BE A DEGREE OR TWO BELOW SEASONAL NORMALS. DRY WEATHER CONTINUES FRIDAY NIGHT INTO SATURDAY WITH HIGHS GETTING TO SEASONAL NORMALS ON SATURDAY. CLOUDS WILL BE ON THE INCREASE THROUGHOUT THE DAY AND ESPECIALLY SATURDAY NIGHT AS AN UPPER LEVEL TROUGH OF LOW PRESSURE BEGINS TO DEVELOP UPSTREAM AND EVENTUALLY MOVES INTO THE REGION LATE SATURDAY NIGHT AND ESPECIALLY SUNDAY. ENOUGH FORCING SHOULD DEVELOP SATURDAY NIGHT FOR A CHANCE OF SHOWERS...WHICH GOING FORECAST ALREADY HAS...AND WILL CONTINUE THIS IDEA. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 315 PM EDT THURSDAY...PRIMARY WEATHER NEWS FOR THE EXTENDED PERIOD IS THE ANTICIPATED DEVELOPMENT OF A LONG-WAVE TROUGH ACROSS THE EASTERN THIRD OF THE COUNTRY THAT WILL RESULT IN A GENERALLY UNSETTLED AND SLIGHTLY COOLER THAN NORMAL FIRST FEW DAYS OF THE WEEK. PRIMARY 12Z GUIDANCE (GFS & ECMWF) STILL IN LINE WITH EACH OTHER AND WITH THEIR RESPECTIVE PRIOR RUNS WITH LARGE SCALE PICTURE WITH THE LONG-WAVE TROUGH. STILL OFFER SLIGHTLY DIFFERENT TIMING WITH RESPECT TO INDIVIDUAL SHORTWAVES THAT WILL BE ZIPPING THROUGH THE FLOW, AND IT`S REALLY THOSE SHORTWAVES THAT WILL DRIVE THE WEATHER WE SEE. BECAUSE OF THE OVERALL SIMILARITY BETWEEN MODELS, I POPULATED THE GRIDDED FORECAST DATASET WITH A BLEND OF THEM ALL. HERE ARE THE DAILY SPECIFICS: SUNDAY...TIMING IS STILL UNCERTAIN, BUT THE MORNING HOURS WE MAY BE DEALING WITH A BATCH OF SHOWERS AND PERHAPS AN EMBEDDED T-STORM THANKS TO A SHORTWAVE PASSING ACROSS THE REGION. WITH SOME BREAKS OF SUN IN THE AFTERNOON THAT COULD BUBBLE UP SOME SCATTERED SHOWERS OR T-STORMS. SURFACE BASED INSTABILITY GUIDANCE FROM THE GFS SHOWS SOME MODERATE INSTABILITY, BUT THAT BEGINS TO WANE BY LATE AFTERNOON. PART OF THIS INSTABILITY MAY BE DRIVEN IN THE MODELS BY THE RATHER HIGH SURFACE DEW POINTS (MID-UPPER 60S). BEST MID LEVEL WINDS AND SHEAR VALUES ARE SOUTH AND EAST OF THE AREA, SO ANY CONVECTION WE DO SEE SHOULD NOT BE ALL THAT ORGANIZED OR STRONG. THAT SAID, BECAUSE OF THE UNCERTAIN TIMING OF THE SHORTWAVE, IF THE SHORTWAVE COMES THROUGH A LITTLE SLOWER, THEN SUNDAY AFTERNOON COULD BE MORE ACTIVE CONVECTIVELY. IN THE END, I JUST PAINTED IN LIKELY LEVEL POPS FOR THE ENTIRE DAY. NO REASON TO TRY TO GET MORE CUTE THAN IS NECESSARY AT THIS POINT. 850MB TEMPERATURES AROUND 13-14C, WHICH UNDER FULL SUNSHINE WOULD SUPPORT LOW/MID 80S FOR HIGHS. HOWEVER, CLOUDS SHOULD HOLD TEMPERATURES BACK TO ABOUT 80F, THOUGH THAT WILL BE HIGHLY DEPENDENT ON WHAT WE SEE FOR SUN. COULD BE HIGHER. COULD BE LOWER. SUNDAY NIGHT/MONDAY...NEXT SHORTWAVE ROUNDING THE BASE OF THE UPPER TROUGH COMES INTO THE REGION. TIMING DIFFERENCES BETWEEN THE MODELS, SO AGAIN WON`T TRY TO SLICE THE BALONEY TOO THIN. SO SOMETIME IN THIS PERIOD WE`LL SEE ANOTHER BATCH OF SHOWERS WITH EMBEDDED T-STORMS ROLL THROUGH. INSTABILITY PARAMETERS IN THE MODELS ARE NOT IMPRESSIVE AT ALL, SO I JUST CALLED IT "SLIGHT CHANCE" FOR T-STORMS. AGAIN, A BUNCH OF CLOUDS AND WITH THE MID/UPPER LEVEL TEMPERATURES FALLING DUE TO THE SLOWLY APPROACHING LONGWAVE TROUGH (850MB TEMPERATURES SHOULD BE 10-12C), MONDAY IS LOOKING A LITTLE COOLER THAN SUNDAY - HIGHS IN THE MID 70S, ABOUT 5-7F BELOW NORMAL. TUESDAY/WEDNESDAY...LONGWAVE TROUGH AXIS WILL BE JUST OFF TO OUR WEST, OVER THE EASTERN GREAT LAKES. AT THIS POINT THE MODELS AREN`T SHOWING ANY SIGNIFICANT SHORTWAVES MOVING THROUGH THE FLOW, SO THE PRIMARY TRIGGER MECHANISM FOR ANY CONVECTION WILL BE DAYTIME HEATING. SO HAVE PAINTED IN CHANCE LEVEL POPS DURING THE DAY AND MINIMAL POPS FOR TUESDAY & WEDNESDAY NIGHTS. 850MB TEMPERATURES CONTINUE TO FALL, AND WILL BE DOWN AROUND 10C. THIS WILL SUPPORT TEMPERATURES IN THE MID 70S AS ADDITIONAL SUN WILL OFFSET THINGS A BIT. THURSDAY...LONGWAVE TROUGH PATTERN LOOKS TO "RELOAD" ACROSS THE CENTRAL PLAINS, SO WEAK RIDGING DEVELOPS OVER US. SHOULD BE THE DRIEST OF THE EXTENDED FORECAST PERIOD, THOUGH ANTICIPATE DAYTIME HEATING TO AGAIN RESULT IN A FEW SHOWERS ESPECIALLY ACROSS THE HIGHER TERRAIN. 850MB TEMPERATURES RISE BACK UP TO 12-13C, SO HIGHS WILL BE CLIMBING CLOSER TO NORMAL WITH UPPER 70S TO PERHAPS LOW 80S. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... THROUGH 00Z SATURDAY...DAYTIME CUMULUS CLOUDS HAVE DISSIPATED THIS EVENING. LAST FEW VISIBLE SATELLITE IMAGES INDICATE SOME HIGH ALTITUDE SMOKE MOVING NW-SE ACROSS OUR REGION...BUT FROM ALL INDICATIONS THIS SMOKE IS ABOVE 20 KFT AND WON/T BE ANY ISSUE FOR GENERAL AVIATION. WINDS BECOMING LIGHT AND VARIABLE...EXCEPT LIGHT SW AROUND 5 KT AT KMSS OVERNIGHT. DESPITE THE MUCH DRIER CONDITIONS...GROUND IS STILL WET FROM YESTERDAY/S RAINFALL...ESPECIALLY CENTRAL AND ERN VT. INCLUDED A FEW HOURS OF IFR FOG AT MPV (08-11Z)...WITH A TEMPO GROUP FOR IFR FOG AT SLK DURING THE PRE-DAWN HOURS. DAYTIME CONDITIONS FRIDAY LOOK VFR WITH SKC-SCT040. OUTLOOK 00Z SATURDAY THROUGH TUESDAY... 18Z FRI - 00Z SUN...VFR. PERHAPS A TOUCH OF OVERNIGHT FOG AT MPV AND/OR SLK. 00Z SUN ONWARD...TRENDING INCREASINGLY UNSETTLED. THOUGH MOSTLY VFR...PERIODIC SHOWERS/STORMS WITH POSSIBLE BRIEF MVFR/IFR VISIBILITY RESTRICTIONS. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...EVENSON NEAR TERM...EVENSON/MUCCILLI SHORT TERM...EVENSON LONG TERM...NASH AVIATION...BANACOS/NASH

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