Severe Thunderstorm Warning 63, NWS Boston/Norton, MA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
300 AM EDT MON JUL 26 1999

...MORE AFTN CNVTCN TDA AND TUE BEFORE DRIER WX ARRIVES FOR MID TO
LATE WEEK...

DISC:  WK FNTL BNDRY REMAINS DRAPED ACRS SE MA AND RI ERLY THIS
MRNG.  ANOTHER MRNG OF WDSPRD ST/FG IN E...SPCLY WHERE LCLY HVY RAIN
FELL YDA AFTN.

ST/FG SHUD BURN OFF BY MID MRNG.  WITH UPR TROF OVR FA AND PLENTY
OF LO LVL MOISTR XPCT PTSUNNY SKIES TDA.  MDLS IN GNRL AGRMNT IN
PINPOINTING GRTST INSTAB ACRS ERN ZNS THIS AFTN...ALTHO SFC BASED
LI'S DROP BLO ZERO OVR ENTIRE FA.  AMS IS CERTAINLY NOT AS UNSTABL AS
OVR WKND...BUT ETA DOES FCST CAPES AS HI AS 1300 ACRS ERN MA BY EVE.
NOT MUCH IN THE WAY OF A LIFTG MECH TO ORGANIZE TSTMS THIS AFTN...
OUTSIDE OF TERRAIN AND SEA BRZ BNDRYS GIVEN WK LO LVL FLO.  ETA
DOES PRODUCE SOME WK LIFT IN THE H85-H7 LYR THIS AFTN AND EVE...PTLY
DUE TO H85 VORT LOBE ROTATG ARND UPR LO.  WL UP POPS TO LKLY IN
PARTS OF E AND SCALE BACK TO CHC W.

NOT LOOKING FOR WDSPRD SVR TDA IN SRN NEW ENG...BUT ISOLD SVR
CERTAINLY NOT OUT OF THE QUESTION IN E.  COLDER TMPS ALF ASSOCTD WITH
UPR TROF FAVORS TO HAIL DVLPMNT...AND DESPITE WK WND FIELD MOMENTUM
TRANSFER CUD PRODUCE STG WND GUSTS...SIMILAR TO WHAT'S HAPPENED THE
PAST COUPLE OF DAYS.  ALSO NOTED A FEW SVR RPTS UPSTREAM IN WRN AND
CNTRL NY SUN AFTN.  NO MNTN IN ZNS ATTM BUT DAY SHIFT CAN RE-ASSESS
AFT LOOKG AT 12Z SOUNDGS.

WL CONT WITH PTCLDY/AREAS OF FOG TNGT AS PRES GRAD REMAINS WK AND
PERSISTENCE SEEMS TO BE THE BEST BET.

UPR TROF PULLS OUT TO OUR E TUE WHICH ALLOWS CDFNT TO APCH FA TWD
EVE.  SOME TIMING DIFF EXIST BTWN MDLS...WITH AVN/NGM A LTL FASTER
THAN ETA...BUT NOT ENUF TO MAKE A BIG DIFF IN FCST.  GRTST INSTAB IS
FCST TO BE ACRS CT/MERR VLYS BY EVE...WHERE ETA YIELDS SFC BASED
CAPES ARND 1300.  WL UP POPS TO HI CHC ACRS BOARD.

AVN BRINGS CDFNT THRU TUE NGT...AND DRIER WX IS IN THE CARDS FOR
WED THRU FRI AS LARGE SFC HI BUILDS INTO FA FM GRTLKS.

FWC TMPS LOOKS GOOD TDA WITH MAXES ABT 5 DEG COOLER THAN SUN BASED
UPON COOLER TMPS AT H85.  WENT SLGTLY ABV FOR TUE AS H85 THERMAL
TROF MOVS OFFSHR AND TMPS RECOVER.

MARINE...LGT WNDS CONT THRU PD ALG WITH REDUCED VSBY IN ERLY MRNG
AND NGTTIME FG.

.BOX...NONE.

JWD