Severe Thunderstorm Warning 28, NWS Burlington, VT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1227 PM EDT TUE JUN 20 2006

.SHORT TERM /REST OF TODAY/...
FORECAST HAS BEEN UPDATED TO REFLECT SEVERE THUNDERSTORM WATCH
# 521...IN EFFECT FOR RUTLAND COUNTY AND MOST OF CENTRAL AND
EASTERN VT THROUGH 00Z.

&&

.PREV DISCUSSION...
 /ISSUED 915 AM EDT TUE JUN 20 2006/

SHORT TERM /REST OF TODAY/...
AT 13Z...SFC COLD FRONT WAS APPROACHING THE ST. LAWRENCE VLY FROM
THE NW. WV IMAGERY REVEALS MID-LEVEL VORT CENTERED NE OF GEORGIAN
BAY. A SEPARATE SHORTWAVE TROUGH WAS TRACKING EWD THROUGH THE MID-
ATLANTIC STATES...WITH AXIS OF ASSOCIATED HIGH CLOUDINESS EXTENDING
NEWD INTO S-CENTRAL VT. OTHERWISE...CONDITIONS ACROSS THE NORTH
COUNTRY WERE PARTLY TO MOSTLY SUNNY WITH LIGHT SOUTH TO SWLY
WINDS. DEWPOINTS REMAIN GENERALLY IN THE LOWER 60S IN ADVANCE OF
THE FRONTAL BOUNDARY...AND SHOULD REMAIN STEADY UNTIL FROPA.

WE CONTINUE TO ANTICIPATE SCATTERED SHOWER AND THUNDERSTORM
DEVELOPMENT ACROSS FAR NRN NY BY NOON...WITH CELLS TRACKING/DEVELOPING
EWD ACROSS VT DURING THE AFTN HOURS. INSTABILITY WILL BE LESS THAN
YESTERDAY. THINK 06Z NAM INSTABILITY IS UNDERDONE WITH SBCAPE
AROUND 500 J/KG...AS MODEL SFC TEMPERATURES APPEAR SEVERAL
DEGREES TOO LOW. EXPECTED TEMPERATURES IN THE MID 70S AND
DEWPOINTS IN THE LOW 60S SHOULD CONTRIBUTE TO SBCAPE VALUES CLOSER
TO 1000 J/KG...FROM THE CHAMPLAIN VLY EWD. COOLING ALOFT APPEARS
MOSTLY POST FRONTAL WITH VORT MAX/THERMAL TROUGH...THUS...MID-
LEVEL LAPSE RATES REMAIN MARGINAL...WITH 700-500MB VALUES AROUND 6
C/KM. SFC-6KM SHEAR WILL GENERALLY BE AROUND 30KTS...WITH DEEP-
LAYER UNIDIRECTIONAL FLOW FROM THE WSW THROUGH MID-AFTN. THIS ALSO
IS LESS THAN YESTERDAY... BUT STILL ADEQUATE FOR SOME LONGER LIVED
CONVECTIVE UPDRAFTS. ALSO FEEL THAT GFS IS TOO AGGRESSIVE WITH MID-LEVEL
TROUGH AMPLIFICATION ACROSS OUR FA THIS AFTN...AND STRONGEST FORCING
--- AND THUS MOST WIDESPREAD CONVECTION -- IS MORE PROBABLE ACROSS
NRN ZONES.

SO...WHILE DYNAMIC FORCING APPEARS FAVORABLE FOR CONVECTIVE DEVELOPMENT
..OVERALL SVR THREAT IS MUCH LOWER THAN YESTERDAY. WE/LL WATCH
FOR VILS OF 45 KG/M2 AND 50-55 DBZ ECHOES ABOVE 23 KFT AS A GENERAL
THRESHOLD FOR PENNY HAIL. ANY SVR WIND SHOULD BE BRIEF WITH
LOCALIZED STRONGER DOWNDRAFTS. BELIEVE CURRENT SUB-SEVERE FORECAST
WORDING IN ZONES AND WX GRID /GUSTY WINDS AND SMALL HAIL/ IS ON
TARGET. WILL FRESHEN THE SPS TO REFLECT ISOLATED SVR WIND/HAIL
THREAT BUT WITH MOST ACTIVITY THIS AFTN BELOW SVR LIMITS.

PREV DISCUSSION...
 /ISSUED 425 AM EDT TUE JUN 20 2006/

SHORT TERM /TODAY THROUGH THURSDAY/...
ANOTHER ROUND OF SHWRS/THNDSTRMS EXPECTED TDY...ALTHO RISK OF SVR
NOT AS GREAT AS IT WAS YESTERDAY.

CDFNT MOVG ACRS SE ONTARIO ATTM WILL MOVE INTO ST LWR VLY AROUND
12Z...ACRS NRN NY DURING MORNING HRS AND VT THIS PM. WK MID LEVEL
SHRTWV ACCOMPANYING THE FRONT. A MORE VIGOROUS SHRTWV MOVG ACRS NRN
GRTLKS ATTM WILL DIG SEWRD AND MOVE ACRS FA THIS PM/EVENING...WITH
SECONDARY WINDSHIFT/FROPA WITH PASSAGE OF THIS FEATURE.

MARGINAL INSTABILITY TDY IN ADVANCE OF CDFNT WITH CAPES EXPCTED TO
RANGE FROM 500 J/KG TO AS HIGH AS 1500 J/KG...WITH HIGHEST VALUES
OVER EASTERN PORTION OF FA DUE LATER TIME OF FROPA. INSTABILITY
DECREASES WITH PASSAGE OF FROPA DUE LLVL DRYING...BUT SHEAR
INCREASES IN ADVANCE OF TRAILING STG SHRTWV. SO RISK OF TSRA WILL
CONTINUE BEYOND PASSAGE OF INITIAL FRONT...INTO THE EVENING HRS.
HAVE KEPT IN SOME ENHANCED WORDING TDY WITH GUSTY WINDS AND SMALL
HAIL...AND IT IS PSBL THAT SOME STORMS MAY APRCH SEVERE LEVELS THIS
PM IN VT.

WITH PASSAGE OF SHRTWV TONIGHT...RISK OF SHRA/TSRA WILL DIMINISH.
EXPECT CLRNG OVRNIGHT. COMBINATION OF CLRNG AND LIGHT WINDS WILL
ALLOW FOR FORMATION OF SOME PATCHY FPG...ESPECIALLY IN THOSE AREAS
THAT EXPERIENCE THE MOST RAINFALL TDY.

HIGH PRESSURE WILL MOVE EAST ACRS FA DURING WEDNESDAY...RESULTING IN
PRTLY TO MSTLY SUNNY SKIES. MAX TEMPS CLOSE TO SEASONAL NORMS FOR
THE FIRST DAY OF SUMMER.

AS HIGH MOVES EAST OF FA WED NIGHT...RETURN SOUTHERLY FLOW DEVELOPS.
WAA COUPLED WITH SHRTWV APRCHG FROM GRTLKS WILL RESULT IN AN
INCREASE IN CLDS OVRNGHT WITH CHC SHRA/TSRA WRN ZONES LATE. RISK OF
SHWRS/THNDSTRMS ACRS ENTIRE FA THURSDAY AS SHRTWV AND ASSOCD SFC
TROF MOVE ACRS RGN. DEPENDING ON AMOUNT OF SUNSHINE AND RESULTANT
LLVL HEATING...MAY BE LOOKING AT POSSIBLE SVR WX ONCE AGAIN.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HAVE NOT MADE ANY CHANGES TO THIS PORTION OF THE FCST ATTM. CDFNT
WILL BRING ANOTHER CHC SHWRS/THNDSTRMS TO FA FRI. FRONT STALLS
SOUTH OF FA FRI NITE/SAT AS FLOW ALOFT RMNS SOUTHWEST. THE RESULT
WILL BE A CONTD CHC OF SHWRS. HIGH PRESSURE GRADUALLY BLDS INTO RGN
FROM NORTH OF GRTLKS LATER IN WEEKEND...ALLOWING FOR DRIER
CONDITIONS EARLY NEXT WEEK.

AVIATION...
PRIMARY WX CONCERN ONCE AGAIN TODAY WILL BE DEGREE/COVERAGE OF
CONVECION DURING LATE MORNING INTO AFTERNOON HOURS. WILL OPT FOR SCT
MVR/IFR CONDS IN PATCHY BR/FG THROUGH 12Z...THEN MAINLY VFR AREA
WIDE UNTIL THREAT OF CONVECTION INCREASES. BEST INSTABILITY APPEARS
TO OCCUR FROM CHVLY EASTWARD TODAY...AND WILL OFFER BEST CHC OF TSRA
AT KBTV-KMPV. ACROSS NRN NY...ACTIVITY WILL OCCUR EARLIER...AND
MAINLY DURING MORNING HOURS...THUS MORE CLOUDS AND LESS CHC FOR
WIDESPREAD THUNDER. NONETHELESS...WILL STILL OFFER BRIEF PERIOD OF
THUNDER EVEN HERE THROUGH NOON. SHORTWAVE/VORT CENTER DROPPING SE
ACROSS AREA LATER TODAY/THIS EVENING SHOULD KEEP AT LEAST BKN/OVC
MID LVL VFR CIGS THROUGH 00Z...THEN CLEARING OVERNIGHT WITH PATCHY
BR/FG ONCE AGAIN POSSBL BY LATE NIGHT.

&&

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

SHORT TERM...BANACOS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BURLINGTON VT
415 AM EDT TUE JUN 20 2006

NYZ026>031-034-035-087-VTZ001>012-016>019-210815-
NORTHERN ST. LAWRENCE-NORTHERN FRANKLIN-EASTERN CLINTON-
SOUTHEASTERN ST. LAWRENCE-SOUTHERN FRANKLIN-WESTERN CLINTON-
WESTERN ESSEX-EASTERN ESSEX-SOUTHWESTERN ST. LAWRENCE-GRAND ISLE-
WESTERN FRANKLIN-ORLEANS-ESSEX-WESTERN CHITTENDEN-LAMOILLE-
CALEDONIA-WASHINGTON-WESTERN ADDISON-ORANGE-WESTERN RUTLAND-
WINDSOR-EASTERN FRANKLIN-EASTERN CHITTENDEN-EASTERN ADDISON-
EASTERN RUTLAND-
415 AM EDT TUE JUN 20 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN NEW
YORK...CENTRAL VERMONT...NORTHEAST VERMONT...NORTHWEST VERMONT
AND SOUTHERN VERMONT.

.DAY ONE...TODAY AND TONIGHT

LOW PRESSURE ACROSS EASTERN CANADA WILL CONTINUE TO MOVE EAST
TODAY...DRAGGING A SURFACE COLD FRONT ACROSS THE NORTH COUNTRY
DURING THE AFTERNOON HOURS. AS A RESULT...SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AGAIN TODAY. THE
ACTIVITY SHOULD DEVELOP ACROSS NORTHERN NEW YORK THIS
MORNING...AND SPREAD EAST INTO VERMONT FROM LATE MORNING INTO THIS
AFTERNOON. WHILE THE THREAT OF SEVERE WEATHER DOES NOT APPEAR AS
GREAT OR AS WIDESPREAD AS ON MONDAY...SOME OF THE STORMS MAY
NONETHELESS BECOME STRONG...WITH GUSTY WINDS AND SMALL HAIL. THIS
MAY LEAD TO LOCALIZED DAMAGE AND SCATTERED POWER OUTAGES. AT THIS
TIME...IT APPEARS THAT THE GREATEST THREAT OF STRONGER STORMS
TODAY SHOULD OCCUR FROM THE CHAMPLAIN VALLEY EASTWARD. BY
TONIGHT...MEAN HIGH PRESSURE WILL BUILD EAST INTO THE
REGION...WITH GRADUALLY CLEARING SKIES AND LIGHT NORTHWEST WINDS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME. EXPECTED PARTLY
CLOUDY SKIES AND SEASONABLE TEMPERATURES DURING WEDNESDAY...THEN A
CHANCE OF ADDITIONAL SHOWERS AND THUNDERSTORMS BY LATER WEDNESDAY
NIGHT INTO FRIDAY AS ENERGY FROM THE MIDWEST MOVES EAST.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER THIS MORNING INTO THIS AFTERNOON.

JMG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
128 PM EDT TUE JUN 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0100 PM     TSTM WND DMG     3 SW ORWELL             43.77N 73.34W
06/20/2006                   ADDISON            VT   PUBLIC

            TREE BRANCHES DOWN AND NO POWER NEAR ORWELL

&&

TABER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
143 PM EDT TUE JUN 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0100 PM     TSTM WND DMG     ESSEX JUNCTION          44.49N 73.11W
06/20/2006                   CHITTENDEN         VT   NWS EMPLOYEE

            LARGE OAK TREE DOWN AND BLOCKING RT. 15. POWER IS OUT AND
            ROAD IS CLOSED.

&&

MURRAY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
206 PM EDT TUE JUN 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0130 PM     HAIL             ST. JOHNSBURY           44.43N 72.01W
06/20/2006  E0.50 INCH       CALEDONIA          VT   PUBLIC

            AT THE ST. JOHNSBURY ACADEMY...TIME APPROXIMATE.

&&

MURRAY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
207 PM EDT TUE JUN 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0155 PM     HAIL             PITTSFIELD              43.78N 72.82W
06/20/2006  E0.25 INCH       RUTLAND            VT   PUBLIC

            REPORTED AT TOWN CLERKS OFFICE.

&&

MURRAY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
211 PM EDT TUE JUN 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0110 PM     HAIL             ST. JOHNSBURY           44.43N 72.01W
06/20/2006  M0.50 INCH       CALEDONIA          VT   TRAINED SPOTTER

0110 PM     TSTM WND GST     ST. JOHNSBURY           44.43N 72.01W
06/20/2006  M35 MPH          CALEDONIA          VT   TRAINED SPOTTER

&&

MURRAY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BURLINGTON VT
240 PM EDT TUE JUN 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     HAIL             SWANTON                 44.92N 73.12W
06/20/2006  M0.25 INCH       FRANKLIN           VT   TRAINED SPOTTER

0239 PM     HAIL             ST. ALBANS              44.81N 73.08W
06/20/2006  E0.25 INCH       FRANKLIN           VT   TRAINED SPOTTER

            AT EXIT 20 ON I-89

&&

MURRAY