Severe Thunderstorm Warning 159, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
225 PM EDT THU AUG 01 2002

SHORT TERM...TNGT THRU FRI NIGHT...

HUGE SUBTROPICAL RIDGE EXTENDING FROM COAST TO COAST WILL ACTUALLY
STRENGTHEN AND BUILD EWD THROUGH FRI NIGHT. MEANWHILE...THE
WESTERLIES REMAIN AT THEIR SUMMER RETREAT ACROSS SRN CANADA AND THE
FAR NRN U.S.

AT THE SFC...HIGH PRES WILL DOMINATE TNGT AND FRI. NGM/ETA DROP A
BOUNDARY SWD INTO THE AREA LATE FRI NGT. AVN IS SLOWER HOLDING
OFF UNTIL EARLY SAT. HOWEVER...WITH RISING 500MB HGTS...STRONG UPR
LVL RDG IN PLACE AND BUILDING...AND DYNAMICS WELL REMOVED TO THE N
OVR SE CANADA...IT SHOULD BE QUITE THE PATHETIC EXCUSE FOR A FRONT
BY THE TIME IT REACHES THIS FAR SOUTH (IF IT EVER GETS THIS FAR
SOUTH). THERE MAY NOT BE ANYTHING BUT A SUBTLE WIND SHIFT. ETA IS
OUT ON ITS OWN IN DVLPG PCPN OVR THE AREA ALG AND AHD OF THE FNT FRI
NGT. THIS APPEARS OVERDONE. THE AVN AND NGM ARE DRY THRU FRI NGT AND
GIVEN THE CIRCUMSTANCES...WILL BE GOING WITH A DRY FCST WITH 10 POPS
EARLY TNGT...10 POPS AGAIN FRI. CANT RULE OUT ISOLD CONVECTION FRI
NGT IF SOMETHING CAN MANAGE TO FIRE FURTHER NW NEAR THE FNT AND
STAGGER INTO THE AREA BUT NO MORE THAN 20 POPS SO IT WILL REMAIN
HIDDEN FOR NOW.

COULD BE AN ISOLD TSTM DUE TO OROGRAPHIC LIFT OVR THE MTNS NEXT FEW
HOURS BUT NOT WORTH MORE THAN A 10 POP SO WILL NOT MENTION ANYTHING.
THIS AFTRNS CU SHUD DISSIPATE WITH SUNSET WITH SCT CU DVLPG ONCE
AGAIN FRI AFTRN. OTHERWISE...SOME THIN CI FM TIME TO TIME. WILL CALL
IT M/CLR TNGT AND M/S ON FRI. WILL GO P/CLDY FRI NGT.

THE HEAT IS A PROBLEM. 850MB TEMPS OVR +20C ON THU. THIS ALG
WITH PLENTY OF SUNSHINE WILL SEND TEMPS BACK INTO THE MID 90S FRI
(COOLER HIER ELEVS) WITH HIEST READINGS IN THE URBAN AREAS OF DC AND
BALTIMORE. NGM/ETA MOS DEWPOINTS AROUND 70F AND MAY BE A DEG OR TWO
HIER IN THE URBAN DC/BALTIMORE AREAS. HEAT INDICES MAY NOT FALL
BELOW 80F IN THE CITIES TNGT AND HEAT INDICES ONCE AGAIN EXPECTED TO
BE 100 TO 105 AGAIN FRI SO WILL CONTINUE THE ADVISORY FOR THE CITIES
THROUGH FRI. OUTSIDE THE CITIES...HEAT INDICES WILL FALL INTO THE
70S TNGT AND HEAT INDICES WILL BE BORDERLINE ADVISORY CRITERIA (100F)
ON FRI SO WILL HOLD OFF ON EXTENDING ADVISORY TO OTHER AREAS FOR NOW.

PNSLWX (NOUS41 KLWX) SENT OUT EARLIER WITH INFO ON THIS SUMMERS
HEAT.

WALSTON

LONG-TERM DISCUSSION (SAT-THU)

WEAK FRONT WILL APPROACH THE AREA ON SAT AND WASH OUT DURING THE DAY
ON SUNDAY.  WILL KEEP SILENT 20 POPS FOR SAT.  UPPER RIDGE OVER THE
CNTRL STATES EXPANDS EWD INTO THE MID ATLANTIC EARLY NEXT WEEK.
WILL CONTINUE WITH A DRY FCST AND TEMPS NEAR NORMAL.

ROSA

.LWX...
DC...HEAT ADVISORY UNTIL 800 PM EDT FRIDAY FOR ZONE DCZ001.
MD...HEAT ADVISORY UNTIL 800 PM EDT FRIDAY FOR ZONE MDZ011.
VA...HEAT ADVISORY UNTIL 800 PM EDT FRIDAY FOR ZONE VAZ054.
WV...NONE.