Flash Flood Warning 14, NWS Boston/Norton, MA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
210 PM EDT THU AUG 26 1999

DISC:  MDLS IN GOOD AGRMNT ON GRDLY WKNG UPR LO AS IT HEADS E
ACRS NYS...BUT REMAIN IN SOME DISAGRMNT REGARDG LO LVL FEATURES WITH
ETA/AVN SLWR IN MOVG FNTL SYS THRU SRN NEW ENG AS OPPOSED TO FASTER
NGM.  NGM ALSO SEEMS TO BE HAVING SOME TROUBLE HANDLING CURRENT
CONVCTN TO OUR S...SO ONCE AGAIN TDA WL LEAN TWD ETA/AVN SOLN.

SHWRS ACRS WRN HALF OF FA ASSOCTD WITH WKNG H85 S/W WL CONT INTO
THIS EVE...BUT SHUD DSIPT BY MIDNGT AS UPR SUPPORT FADES AWAY.
WL MNTN POPS THIS EVE PRIMARILY IN W.  OTRW XPCT LO CLDS AND FG TO
RETURN TNGT AS LO LVL SE FLO OFF OCEAN CONTS.  ETA HINTS AT NXT
S/W CURRENTLY ASSOCTD WITH TSTMS OVR NC HEADG TWD S COAST BY
MRNG...SO WL ALSO INTRODUCE SOME PCPN ALG SRN RI AND CAPE/ISL TWD
DAYBRK.

WMFNT SLWLY LIFTS N OF FA FRI AFTN.  PLENTY OF LO LVL MOISTR AND
LIFT AHEAD OF IT SHUD RESULT IN SHWRS AND SCTD TSTMS ACRS FA FRI
SO WL CONT WITH LKLY POPS ALL ZNS.  PER ABV THINKG NGM APPEARS TO BE
TOO FAST IN LIFTING WMFNT THRU...AND PREFER TO GO SLWR ETA ROUTE.
AMS REMAINS FAIRLY STABLE..ASIDE FM CT ZNS WHICH ARE CLOSEST TO
INSTAB AXIS WHICH LIES JUST TO OUR W.  WL ADD PSBLTY OF TSTMS IN
ALL ZNS BASED UPON THIS WMFNTS RECORD SO FAR...BUT XPCT MOST IF
NOT ALL TSTM ACTVTY ACRS SW PTN OF FA.

SW FLO TAKES OVR FRI NGT AS WMFNT LIFTS N.  ALTHO LL MOISTR REMAINS
PLENTIFUL...THERES NOT MUCH UPR SUPPORT OR LL BNDRY TO FOCUS ANY
PCPN.  WL OPT TO LEAVE FRI NGT DRY...ALTHO WUDNT BE SURPRISED TO
SEE SOME ISOLD ACTVTY WHICH LATER FCSTS CAN ADD.

A RETURN (ALTHO BRIEF) TO WARM AND HUMID WX ARRIVES SAT.  XPCT CDFNT
TO REMAIN W OF FA AS FNT BECOMES ALIGNED WITH UPR FLO...RESULTING
IN A SW/W FLO WHICH SHUD SEND TMPS SOARING WELL INTO 80S XCPT FOR
S COAST.  WITH PLENTY OF LL MOISTR...DECENT INSTABY AND BNDRY W OF
FA WL OPT TO INCLUDE CHC POPS (HIEST E) SAT.  XPCT MOST OF ACTVTY
TO BE DURG AFTN...BUT WITH ETA INDCTG SOME MSRBL PCPN IN WRN ZNS
DURG MRNG WL NOT BE SPECIFIC THERE.

XTNDED...CDFNT IS PROGGED TO MOVE OFF COAST SUN SO WL PRBLY RESTRICT
PCPN TO ERN ZNS ONLY.  RMNDR OF XTNDED DEPENDS ON WHAT DENNIS WL DO
AS IT APCHS SERN U.S.  WL BASE FCST ON LTST THINKG FM HPC...WHICH
TAKES DENNIS NEAR NC COAST THEN TURNS IT NEWD AS IT RUNS INTO
INFLUENCE OF NRN STREAM S/W AND INTERACTS WITH SFC FNT OFF COAST.

THAT SCENARIO IS THE BEST COURSE OF ACTION ATTM WITH MED RANGE MDLS
SHOWING LARGE DISPARITIES IN THEIR RESPECTIVE SOLNS.  UKMET REMAINS
MOST XTREME IN SHOWING LARGE E COAST TROF WHICH LIFTS SYS NWD UP
COAST...MRF WANTS TO TURN DENNIS SHARPLY NEWD AND OFF COAST...AND
NOGAPS CONTS ITS TREND OF THE PAST COUPLE OF DAYS OF INDCTG DENNIS
WL MISS EFFECTS OF NRN S/W AND SIT SOMEWHERE OFF CAROLINAS FOR A FEW
DAYS.  12Z AVN IS INCONCLUSIVE BUT SHOWS AN INTERESTG SITU...AS IT
DVLPS SRN STREAM CUTOFF OVR GULF COAST MORE THAN ETA AT 48HRS.  NXT
NRN STREAM S/W COMING DOWN FM UPR GRTLKS SHUD BE ENUF TO GIVE DENNIS
A KICK TO THE NE...BUT DO HAVE TO CONSIDER THE ...LO PROBABILITY...
OF THAT S/W PHASING WITH SRN STREAM SYS A LA UKMET.

MARINE...NO PRBLMS THRU PD AS SE FLO GIVES WAY TO SW FLO FRI NGT AND
SAT.  XPCT WNDS TO REMAIN BLO SCA ATTM.

.BOX...NONE.

JWD