Severe Thunderstorm Warning 194, NWS Baltimore/Washington

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1149 PM EDT TUE AUG 13 2002

.UPDATE...WITH ISLTD TSRA CONTG W OF THE SHEN VLY...WL NEED TO UPDT
ZFP TO FRESHEN WORDING. WL KEEP 20 POP GOING OVNGT IN THE W...AND
RMV MIDNGT MNTN /AND POPS/ IN THE E.  ZFP ASAP.

ON ANTHR VEIN...HEAT ADVSRY WL BE UPGRADED TO WRNG FOR SOME AREAS W/
SKED PKG 3-4AM...THE EXTENT OF WHICH STILL TBD.

HTS

WITH RECENT UPRAMP IN ACTVTY OVR THE PAST 20 MINS...WILL HOLD ON ANY
UPDATES UNTIL THESE STORMS EITHER CONTINUE OR DISSPTE LIKE THE LAST
ROUND. INSTAB IS STILL AROUND AND WK FORCNG COULD KEEP IT GOING PAST
MIDNGHT BUT THAT WILL BE EVIDENT SOON. EXCSVE HEAT WARNING WILL
LIKELY BE NEEDED WITH THE NEXT FORECAST UPDATE FOR WASH AND BALTO.
HEAT INDCS IN THE 90S FOR BOTH WASH AND BALTO. RECORDS WERE SET
TODAY FOR DULLES AND BALTO...WASH MISSD BY 1 DEG EVEN WITH A 100 DEG
HIGH.

STRONG

WBCAFDLWX
130 PM EDT TUE AUG 13 2002
SHORT TERM...TNGT THRU WED NGT...

UPR LVL RIDGE HOLDS IN PLACE OVR THE WRN ATLC DURING THE NEXT 48
HRS. AT THE SFC...BERMUDA HIGH PRES WILL EXTEND WWD INTO THE REGION.
VERY WEAK SHORTWAVES COMING AROUND THE BACKSIDE OF THE UPR LVL RIDGE
WILL RIDE NWD THRU THE AREA DURING THE NEXT 3 PDS.

AIR MASS IS UNSTABLE OVR THE REGION THIS AFTRN WITH CAPES OF
2500-4000 J/KG...LIS OF -4C TO -6C AND 850-500MB LAPSE RATES OF
7C/KM. THERE IS NO SYNOPTIC SCALE TRIGGER MECHANISM TO PRODUCE
CONVECTION. HOWEVER...SCT/ISOLD CONVECTION MAY FIRE OVR THE MTNS DUE
TO OROGRAPHIC LIFT AND MAYBE ALONG MESOSCALE BOUNDARIES ELSEWHERE
FOR THE REMAINDER OF THE AFTRN. ETA DOES SHOW A VERY WEAK AND SMALL
SHORTWAVE LIFTING NWD THRU THE AREA DURING THE EVENING. THIS MAY
ALSO IGNITE SOME SCT/ISOLD CONVECTION DURING THE EVE. WILL KEEP 30
POPS GOING INTO THE EVE FOR ALL AREAS. OTHERWISE...JUST SOME CI
OVRNGT SO M/CLR.

WE WILL BE IN THE SAME SITUATION ON WED INTO WED EVE. WARM AND MOIST
S FLOW ON THE BACKSIDE OF THE BERMUDA HIGH WILL COMBINE WITH AFTRN
HEATING TO CREATE AN UNSTABLE ATMOSPHERE. HOWEVER...ONCE
AGAIN...THERE DOES NOT APPEAR TO BE ANY SIGNIFICANT SYNOPTIC SCALE
FEATURE TO TRIGGER CONVECTION. ONCE AGAIN...EXPECT ISOLD OR SCT
AFT/EVE ACTIVITY TO FORM OVR THE MTNS DUE TO OROGRAPHIC LIFT AND
PERHAPS ELSEWHERE ALONG MESOSCALE BOUNDARIES THAT MAY BE PRESENT. IN
ADDTN...ETA MODEL HINTING AT ANOTHER VERY WEAK VORT MAX MOVING NWD
INTO THE AREA. ALL OF THIS WARRANTS MENTION OF AT LEAST ISOLD
CONVECTION ON WED INTO WED EVE. WOULD LIKE TO GO WITH 20 POPS.
HOWEVER...IF I DO THAT...I CANT MENTION ACTIVITY IN THE ZNS SO WILL
GO WITH 30 POPS FOR AFT/EVE CONVECTION. OTHERWISE...M/SUNNY FOR WED
AND P/CLDY FOR WED NGT.

850MB TEMPS CHG LITTLE OVR THE NEXT 48 HRS WITH 850MB TEMPS ONCE
AGAIN AROUND +21C WED AFTRN. AVN/NGM MOS HAS BEEN A BIT TOO COOL
LATELY ON MAX TEMPS WHILE THE SLIGHTLY WARMER ETA MOS HAS BEEN
CLOSER TO REALITY.  WILL LEAN TOWARD THE WARMER ETA MOS FOR WED AND
GO FOR THE CENTURY MARK ONCE AGAIN IN DC AND BALTIMORE WITH
SURROUNDING AREAS IN THE 96 TO 101 RANGE. COOLER IN THE HIER
ELEVATIONS. NGM/ETA/AVN MOS ARE CLOSE ON MINS AND ACCEPTED WITH ONLY
MINOR ADJUSTMENTS.

HEAT ADVISORY CONTINUES THRU WED. WE WILL BE FLIRTING WITH WARNING
CRITERIA IN THE CITIES. MID SHIFT CAN TAKE ANOTHER LOOK AT THIS AND
UPGRADE THEN IF NECESSARY.

WALSTON

LONGER...THU THROUGH TUE...

NOT MUCH CHG IN THE OVERALL PATTERN IN THE NEXT SIX DAYS. SUB TROP
RDG WILL REMAIN DOMINANT FEATURE IN THE SERN US...AND IT WL BE
DIFFICULT FOR ANYTHING TO PENETRATE THIS. BEST CHC LOOKS TO BE THU AFTN
AS MINOR SHRT WV PASSES TO THE W/NW OF THE FA. AIR MASS CERTAINLY
MOIST ENOUGH...SO AFTN/EVE CONVECTION IS A PSBLTY. WL BREAK IT 40
POP IN THE W/30 E OF THE MTNS.

BYND THAT MID ATLC REMAINS LOCKED IN A SUMMERTIME PATTERN. EXPECT TO
SEE AFTN HIGHS IN THE LM90S MOST PLACES. TOO FAR INTO THE FUTURE TO
SAY THAT ANY ONE PLACE WL HAVE TRW. THIS IS PSBL BUT W/O MDLS
SHOWING ANY VSBL TRIGGERS WL OMIT AND WAIT UNTIL THE PICTURE BECOMES
CLEARER.

WOODY

.LWX...
DC...HEAT ADVISORY THROUGH WED FOR ZONE DCZ001.
MD...HEAT ADVISORY THROUGH WED FOR ZONES
     MDZ002>007...MDZ009>011...MDZ013>014...MDZ016>018.
VA...HEAT ADVISORY THROUGH WED FOR ZONES
     VAZ025>031...VAZ036>042...VAZ050>057.
WV...HEAT ADVISORY THROUGH WED FOR ZONES
     WVZ048>053...WVZ055.