Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 010722
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
322 AM EDT WED JUL 1 2015

.SYNOPSIS...
MOSTLY CLOUDY SKIES WITH SCATTERED SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS EXPECTED TODAY AS A TROUGH OF LOW PRESSURE LIFTS
NORTHEASTWARD ACROSS THE NORTH COUNTRY. A FEW STRONGER THUNDERSTORMS
ARE POSSIBLE ACROSS VERMONT THIS AFTERNOON...AND MAY PRODUCE GUSTY
WINDS AND HEAVY DOWNPOURS. AS THE LOW PRESSURE AREA DEPARTS
NORTHEASTWARD ACROSS CENTRAL QUEBEC TONIGHT...A DRIER AIR MASS WILL
MOVE INTO THE NORTH COUNTRY RESULTING IN GENERALLY PLEASANT WEATHER
CONDITIONS AND LOW HUMIDITY FOR THURSDAY...FRIDAY...AND
INDEPENDENCE DAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 317 AM EDT WEDNESDAY...AMPLIFIED MID-LEVEL TROUGH EXTENDING
NORTH-SOUTH FROM SERN ONTARIO ACROSS ERN OH/WV EARLY THIS MORNING
WILL ACQUIRE SLIGHT NEGATIVE TILT AS IT TRANSLATES NEWD ACROSS NY
LATE THIS MORNING AND ACROSS VERMONT THIS AFTERNOON. MODERATELY
STRONG HEIGHT FALLS (BY EARLY JULY STANDARDS)...CYCLONIC FLOW AND
MID-LEVEL DIFFERENTIAL VORTICITY ADVECTION WILL ALL CONTRIBUTE TO
LARGE-SCALE ASCENT AND SCATTERED TO WIDESPREAD SHOWER ACTIVITY. IT
APPEARS SHOWERS WILL BE MOST WIDESPREAD THIS AFTN...BUT
PREVAILING MOSTLY CLOUDY CONDITIONS AND COOLING INFLUENCE OF
WIDESPREAD SHOWERS MAKE FORECAST MAX SURFACE- BASED INSTABILITY A
BIT UNCERTAIN FOR THE AFTERNOON. MOST OF THE NUMERICAL
GUIDANCE...INCLUDING NAM12/GFS/LOCALLY RUN BTV-4KM WRF INDICATE
SBCAPE VALUES 1000-1500 J/KG ACROSS CENTRAL AND SRN VT AND
PORTIONS OF THE CHAMPLAIN VALLEY...WITH GENERALLY 500-1000 J/KG
ACROSS NRN NY. SWLY SFC-6KM SHEAR IS GENERALLY 25-30
KTS...SUGGESTING SOME STORM ORGANIZATION IF INSTABILITY CAN
MATERIALIZE AS FORECAST. WOULD ANTICIPATE A FEW STRONGER
STORMS...MAINLY ACROSS VT...DURING THE AFTERNOON HOURS WITH GUSTY
WINDS AND HEAVY DOWNPOURS. CAN/T COMPLETELY RULE OUT A SEVERE
STORM OR TWO...WITH BEST POTENTIAL CENTRAL/S-CENTRAL VT...BUT WILL
DEPEND ON DEVELOPMENT OF SURFACE BASED INSTABILITY AS BEST MID-
LEVEL FORCING MOVES THRU CENTRAL VT THIS AFTERNOON. SPC 21Z CALIBRATED
SREF PROBABILITY OF SEVERE STORMS SHOWS SOME LOW POTENTIAL ACROSS
VT THIS AFTN (HIGHEST 18-21Z) AND INITIAL 06Z SPC DAY 1 OUTLOOK
CARRIES 5% PROBABILITY OF SVR HAIL/WIND WITHIN 25 MILES OF A
POINT. WILL CARRY MENTION OF SUB-SEVERE WIND IN THE GRIDS AND WILL
CONTINUE TO MONITOR MESOSCALE TRENDS INTO THE DAYLIGHT HRS.

HIGHS TODAY GENERALLY EXPECTED IN THE MID-UPR 70S WITH DEWPOINTS IN
THE 60-65F RANGE. GRADIENT FLOW SUPPORTS SOUTHERLY WINDS 10-15 MPH
ACROSS MOST OF THE AREA LATE THIS MORNING THROUGH MID AFTN BEFORE
GRADUALLY DIMINISHING THIS EVENING. GUSTS 25-30 MPH POSSIBLE THIS
AFTN.

HIGHEST POP VALUES GENERALLY THIS AFTERNOON (70-90%)...AND THEN
RAPIDLY DIMINISHING AFTER 00Z AS MID-LEVEL TROUGH AXIS SHIFTS NORTH
AND EAST OUT OF THE AREA. WILL SEE A WESTERLY WIND SHIFT WITH A
MODEST ACCOMPANYING COLD FRONT PASSING THRU 00-03Z WITH TEMPERATURES
DROPPING BACK INTO THE MID 50S FOR MOST AREAS. SHOULD BE ENOUGH LOW-
LEVEL FLOW AND LINGERING CLOUDS THRU AT LEAST THE FIRST HALF OF
TONIGHT TO LIMIT NOCTURNAL FOG DEVELOPMENT IN MOST AREAS.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 317 AM EDT WEDNESDAY...DEEP-LAYER CYCLONE LIFTS OUT NEWD
ACROSS QUEBEC BY DAYBREAK THURSDAY. 00Z GFS/NAM MODEL SOUNDINGS
INDICATE SUBSTANTIAL LOW TO MID-LEVEL DRYING IN THE WAKE OF THIS
SYSTEM IN PREVAILING MODERATELY STRONG WESTERLY FLOW REGIME...AND
SHOULD YIELD MOSTLY SUNNY SKIES FOR THE BALANCE OF THE DAY. IT
WILL FEEL PLEASANT WITH SURFACE DEWPOINTS FALLING INTO THE MID 40S
BY AFTERNOON. DAYTIME MIXING/INSOLATIONAL HEATING WILL RESULT IN
WESTERLY SURFACE WINDS OF 8-14 MPH 15-23Z. 850MB TEMPERATURES
AROUND +8C AND SUNSHINE SUPPORTS VALLEY HIGH TEMPERATURES
GENERALLY IN THE MID 70S. NO PRECIP IS EXPECTED.

WEAK SURFACE RIDGE BUILDS INTO THE REGION FROM THE WEST THURSDAY
NIGHT AND WILL BE ACCOMPANIED BY 1000-500MB MEAN RH VALUES OF 20-30
PERCENT. ALL IN ALL A QUIET AND MOSTLY CLEAR NIGHT WITH LIGHT AND
VARIABLE WINDS CONTROLLED BY LOCAL OROGRAPHIC EFFECTS. WITH MOIST
SOIL CONDITIONS...WILL LIKELY SEE SOME PATCHY FOG FORMATION IN THE
FAVORED VALLEY LOCATIONS 06-12Z FRIDAY. GOOD RADIATIONAL COOLING
WILL RESULT IN WIDE TEMPERATURE RANGE FROM THE MID 40S ACROSS THE
NRN ADIRODNACKS AND VERMONT/S NORTHEAST KINGDOM...TO THE LOW-MID 50S
IN THE CHAMPLAIN VALLEY (WARMEST NEAR LAKE CHAMPLAIN).

CONTINUED PLEASANT WEATHER CONDITIONS FRIDAY/FRIDAY EVENING WITH
MAINTENANCE OF WEAK RIDGING SURFACE AND ALOFT AND <30% MEAN
1000-500MB RH VALUES. 850MB TEMPS MODERATE SOME TO +10 TO +12C AND
SHOULD SEE VALLEY HIGHS IN THE UPPER 70S...BUT WITH CONTINUED LOW
DEWPOINTS IN THE MID-UPR 40S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 300 PM EDT TUESDAY...PRIMARY WEATHER STORY FROM THE JULY
4TH HOLIDAY WEEKEND INTO EARLY NEXT WEEK WILL GENERALLY BE FOR
HIGH PRESSURE, DRY WEATHER AND SEASONABLY WARM TEMPERATURES TO BE
THE RULE. A WEAK AND DECAYING FRONTAL BOUNDARY MAY SPARK A FEW
STRAY SHOWERS AND/OR STORMS ACROSS THE NORTH ON SATURDAY EVENING,
BUT BY AND LARGE A ZONAL WEST TO EAST FLOW WITH BROAD SUBSIDENCE
UNDER THE MEAN HIGH PRESSURE CELL SHOULD DOMINATE WITH LITTLE
AIRMASS CHANGE AND MINIMAL PRECIPITATION EXPECTED. SOME EVIDENCE
THAT AS WE PROGRESS INTO NEXT WEEK HEIGHTS WILL HAVE A TENDENCY TO
BUILD SLIGHTLY, SUGGESTING TEMPERATURES MAY TREND A TAD WARMER AS
WE TRANSITION INTO DEEPER SOUTHERLY FLOW ON THE BACK SIDE OF THE
HIGH. GIVEN SUCH CONSISTENCY AMONG THE GLOBAL SOLUTIONS HOWEVER,
NO BIG CHANGES WERE OFFERED WITH THIS PACKAGE SHOWING TEMPERATURES
RANGING FROM THE MID 70S TO LOWER 80S BY DAY AND IN THE 50S TO
AROUND 60 AT NIGHT, AGAIN, WITH THE SLIGHTLY WARMER READINGS
OCCURRING TOWARD THE MONDAY/TUESDAY TIME FRAME.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...CURRENT RADAR SHOWS A CLUSTER OF SHOWERS
WITH EMBEDDED LIGHTNING STRIKES ACROSS CENTRAL/EASTERN NY...WHICH
IS TRACKING TOWARD OUR TAF SITES. EXPECTING RAIN TO ARRIVE BTWN
07Z-09Z...WITH PERIODS OF MVFR CIGS/VIS POSSIBLE. MPV HAS FOG IN
THIS MORNING WITH 1/4SM VIS AND CIGS AT 100 FEET...BUT THINK THIS
FOG WILL LIFT WHEN RAIN ARRIVES BTWN 07Z-08Z. ELSEWHERE...CIGS
WILL CONTINUE TO COME DOWN AS MOISTURE INCREASES WITH MVFR CIGS
LIKELY AT MOST TAF SITES BY 12Z THIS MORNING...ALONG WITH LIGHT
SOUTH WINDS. MVFR/IFR CONDITIONS WILL PREVAIL TODAY WITH
ADDITIONAL SHOWERS/STORMS EXPECTED AFT 16Z. SOME OF THE STRONGER
STORMS WILL BE CAPABLE OF BRIEF GUSTY WINDS...LIGHTNING...AND
HEAVY DOWN POURS...WHICH WILL REDUCE VIS BLW 3SM AT TIMES. HAVE
USED A TEMPO GROUP BTWN 16Z AND 19Z TO COVER THUNDERSTORM
POTENTIAL THIS AFTN...WITH GREATEST CONCENTRATION OF STORMS OVER
OUR CENTRAL/EASTERN TAF SITES...BTV/PBG/RUT/MPV/SLK. SLOW CLEARING
WITH VFR CONDITIONS WILL DEVELOP BY EVENING.

OUTLOOK 06Z THURSDAY THROUGH MONDAY...
VFR WITH WEAK SFC HIGH PRES...EXCEPT FOR IFR IN FOG/BR AT MPV/SLK
BTWN 06Z AND 12Z THURS AND AGAIN ON FRIDAY. UNCERTAINTY ON SHOWER
POTENTIAL THIS WEEKEND...WITH LATEST TRENDS SHOWING THE POTENTIAL
FOR ADDITIONAL ISOLATED SHOWERS SATURDAY AND AGAIN ON
SUNDAY...WITH BRIEF MVFR CIGS POSSIBLE AT SLK/MPV.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...JMG
AVIATION...TABER


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