Severe Thunderstorm Warning 53, NWS Boston/Norton, MA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1049 AM EDT SUN JUL 25 1999

DISC:  FORECAST A BIT MORE COMPLICATED THIS AM AND MODELS ARE NOT
HANDLING THE MINOR (BUT IMPORTANT) DETAILS WELL.  OVERALL...UPPER
TROF TO PASS THROUGH NEW ENGLAND THIS AFTERNOON.  COLDER TEMPS ALOFT
AND SFC HEATING WILL CREATE INSTABILITY NECESSARY FOR CONVECTION...
QUESTION IS WHERE AND HOW STRONG.  AT SFC...BOUNDARY CURRENTLY OVER
HIGHER ELEVATIONS OF WRN MA.  TO THE WEST...TD/S IN THE UPPER 50S
TO LOWER 60S AND WNW FLOW.  OVER MOST OF MA...WINDS WERE LIGHT WITH
TD/S IN THE UPPER 60S TO LOWER 70S (SOUPIER OVER ERN MA/RI).  MSAS
ACTUALLY SHOWS WEAK SFC LOW OVER CENTRAL MA/RI WHICH HAS REMAINED
NEARLY STATIONARY AND MAY BE MOVING SLOWLY EAST.  FOR WRN MA...XPCT
WINDS TO BECOME WESTERLY WITH DROPPING TD/S.  ALTHOUGH CONVECTION
IS LIKELY WITH ANOTHER LOBE OF VORTICITY SWINGING THROUGH DURING THE
AFTERNOON...NOT CONFIDENT THAT STORMS WILL REACH SEVERE CRITERIA.
HOWEVER...ALTHOUGH DRYING OUT WILL OCCUR...ATM WILL CONTINUE TO
DESTABILIZE WITH SFC HEATING AND LOW WBZ DOES INCREASE CHANCES FOR
HAIL.  IT/S THE ESTRN (AND MAINLY UNTAPPED SERN) ZONES THAT I AM MOST
CONCERCED ABOUT. TD/S ARE HIGH AND THIS AREA REMAINS E OF FRONTAL
ZONE DURING PEAK AFTERNOON HEATING.  ADDITIONALLY...BOS SHOWING AN
ENE WIND AIDED BY WEAK LOW CIRCULATION.  THIS MAY ADD TO SFC
CONVERGENT ZONE DURING AFTERNOON.  OVERALL...WILL EMPHASIZE STRONGEST
STORMS IN E AND PRIMARILY SE ZONES THIS AFTERNOON.  ADJ WILL HAVE TO
BE MADE FOR TEMPS AND WINDS TO ACCOUNT FOR LOCAL EFFECTS.  CLOUDS
HOLDING TIGHT FOR NOW IN NE MA...WILL GRADUALLY DISSIPATE...UNLESS
TROFFINESS AND WEAK LOW REMAINS STATIONARY DURING THE DAY...
BUhT XPCT A SLOW EASTWARD MOVEMENT.

.BOX...SCA CHH-WATCH HILL INCLUDING BUZZARDS BAY AND THE SOUNDS.

DCY

CTZ002>004-MAZ002>024-NHZ011-012-RIZ001>007-261005-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAUNTON MA
1200 PM EDT SUN JUL 25 1999

...ANOTHER ROUND OF THUNDERSTORMS ACROSS SOUTHERN NEW ENGLAND
THIS AFTERNOON AND EVENING MAY BECOME SEVERE...

AN AREA OF LOW PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY OVER
SOUTHERN NEW ENGLAND WILL BE A FOCUS FOR MORE THUNDERSTORM ACTIVITY
THIS AFTERNOON AND EVENING.  THE COMBINATION OF WARM MOIST AIR AHEAD
OF THE FRONT AND COLDER AND DRIER AIR BEHIND THE FRONT WILL MAKE THE
ATMOSPHERE VERY UNSTABLE TODAY...PRODUCING ANOTHER ROUND OF
POTENTIALLY STRONG THUNDERSTORMS.

SOME OF THE THUNDERSTORMS MAY BE ACCOMPANIED BY FREQUENT LIGHTNING...
STRONG GUSTY WINDS AND LARGE HAIL. TORRENTIAL RAINFALL ACCOMPANYING
SOME OF THESE STORMS WILL CREATE LOCALIZED STREET FLOODING AND RAPID
RISES ON SMALL STREAMS.

ALTHOUGH STRONG AND POSSIBLY SEVERE THUNDERSTORMS CAN OCCUR ANYWHERE
IN SOUTHERN NEW ENGLAND THIS AFTERNOON...THE GREATEST RISK OF SEVERE
THUNDERSTORMS THIS AFTERNOON WILL MOST LIKELY EXTEND FROM THE
WORCESTER HILLS AND NORTHEAST CONNECTICUT EAST THROUGH THE REMAINDER
OF MASSACHUSETTS AND RHODE ISLAND.  SOUTHEAST MASSACHUSETTS AND RHODE
ISLAND ARE PARTICULARLY VULNERABLE TO SEVERE THUNDERSTORM POTENTIAL
AS THIS REGION WILL BE VERY MOIST AND UNSTABLE AND HAS AVOIDED MOST
OF THE THUNDERSTORM ACTIVITY DURING THE LAST COUPLE OF DAYS.  LOWER
CLOUDS ACROSS NORTHEAST MASSACHUSETTS WILL DELAY SURFACE HEATING FOR
A TIME...BUT STRONG THUNDERSTORMS WILL STILL BE POSSIBLE LATER IN THE
AFTERNOON.

STORMS HAVE ALREADY BEGUN TO DEVELOP ACROSS NEW HAMPSHIRE AND
FURTHER DEVELOPMENT THROUGHOUT SOUTHERN NEW ENGLAND IS
ANTICIPATED THROUGHOUT THE AFTERNOON AND EVENING.  THE BEST CHANCE OF
SEVERE THUNDERSTORMS WILL OCCUR FROM 2 PM THROUGH 8 PM THIS EVENING.

SPOTTERS AND AMATEUR RADIO OPERATORS SHOULD ONCE AGAIN GEAR UP BY
EARLY THIS AFTERNOON AND BE PREPARED TO RELAY REPORTS DURING THE
AFTEZRNOON AND EVENING SHOULD SEVERE WEATHER DEVELOP.

DCY