Severe Thunderstorm Warning 59, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
240 PM EDT SAT MAY 13 2000

...SHORT TERM...

AT 18Z...WK BNDRY DRAPED OVR THE NE ZNS SLOWLY MOVING NEWD IN RESPONSE
TO SW FLO AHEAD OF APPROACHING CDFNT. S OF THE BNDRY...OVER MUCH OF
THE CWA...ATMS IS VERY UNSTABLE WITH LIS AROUND -10...CAPES OF 3500 TO
4500...AND DWPTS IN THE 70S. ATMS ALSO BEGINNING TO DESTABILIZE OVR NE
ZNS AS BNDRY MVS NWD. OLD OUTFLOW BNDRY OVR WRN ZNS NOW ACTING AS A
FOCUS FOR REDVLPMT OF CNVCTN. EXPECT PREFRONTAL CNVCTN TO INTENSIFY AND
MV EWD DURING THE REST OF THE AFTRN. MAIN THREAT WL BE LARGE HAIL AND
SPOTTY DAMAGING WINDS. NOT A LOT OF DIRECTIONAL SHEAR TO SUPPORT
TORNADOES. HWVR...CELLS THAT FORM AT THE INTERSECTION OF THE
APPROACHING BNDRY WITH THE OLD BNDRY DRAPED OVR THE NE ZNS WL HAVE TO
BE WATCHED CLOSELY. WATCHBOX OUT.

CDFNT PUSHES E OF THE CWA BY 03Z. WL KEEP A RMDNR OF AFT PD E OF THE
BLUE RDG AND KEEP TSRA GOING IN OUR SE COUNTIES INTO THE EARLY OVRNGT
PD.

...LONG TERM...

LONGWAVE TROF SETS UP OVR ERN PTN OF THE NATION SUN THRU MON. AT THE
SFC...HI PRES BUILDS OVR THE AREA...BUT SLIPS OFFSHR MON. A VORT MAX
ROTATING AROUND THE UPR LVL TROF WL SEND ANOTHER WK BNDRY THRU THE AREA
LATE MON.

FCST WL BE SUNNY SUN AND CLR SUN NGT. AVN AND ETA HINT AT SOME CLNDS ON
MON AS WE GET RETURN FLOW AROUND THE DEPARTING SFC HI AND THE WEAK
FRONT APPROACHES FROM THE NW. WL GO P/S 4TH PD.

DWPTS FCSTD TO FALL INTO THE LWR 40S SUN THRU MON RESULTING IN LOW
HUMIDITY. FOR TEMPS...AVN AND NGM MOS WITHIN A FEW DEG OF ONE ANOTHER
WITH THE AVN LEANING ON THE COOL SIDE. WENT WITH A BLEND OF THE AVN AND
NGM MOS 2ND & 4TH PDS.  WENT SLIGHTLY BELOW GUIDANCE 3RD PD AS SKC
ALONG WITH LGT WINDS WL RESULT IN GOOD RADIATIONAL COOLING.

BEYOND 4TH PD...HIGH PRES BUILDS INTO THE AREA TUE & WED WITH NEAR
NORMAL TEMPS AND LOW HUMIDITY. COULD SEE SOME CLOUDINESS RETURN THU AS
SFC HI SLIPS OFFSHR AND WMFNT APPROACHES FM THE W.

.LWX...NONE.