Severe Thunderstorm Warning 59, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1130 AM EST MON MAY 17 2004

UPDATE...
ALL PRODUCTS ALREADY RELEASED. BIGGEST CHG TO PCKG WAS TO UP POPS TO
50 ACRS MOST OF THE AREA. GIVEN THE REMNANTS OF THE FNT WHICH
PERSISTS IN THE MID ATLC...CAPES HIGHER THAN THEYVE BEEN IN PRVS
DAYS...AND THE FACT THAT THERE WERE MULTIPE RW/TRW IN PRVS DAYS FEEL
COMFORTABLE W/ THIS. WIND FIELD IS NEGLIBLE...SO FEEL THAT BIGGEST
PROB WOULD BE HVY RAINS IN SLOW MOVING STORMS.

WOODY

.SHORT TERM (TODAY THROUGH TONIGHT):
WATER VAPOR LOOP SHOWS A TROUGH ACROSS CENTRAL CANADA...WITH RIDGING
ACROSS THE SOUTHEAST CONUS. THE MIDLEVEL SHEAR AXIS LAYS ACROSS THE
MID ATLANTIC REGION...WITH UPSTREAM SHORTWAVES/MCVS ACROSS THE UPPER
MIDWEST. ACARS 250-400MB WIND SPEED OBSERVATIONS SHOW A 115KT JET
STRETCHING FROM CENTRAL CALIFORNIA INTO THE CENTRAL ROCKIES...WHILE
A 130KT JET LAYS FROM THE UPPER MIDWEST...ACROSS SOUTHEAST CANADA.
03Z SURFACE ANALYSIS PLACES A WEAK STATIONARY BOUNDARY ACROSS THE
LEE OF THE APPALACHIANS...WEST AND NORTH TOWARDS A 1006MB LOW OVER
SOUTHEAST SOUTH DAKOTA.

WITH THE INFLUENCE OF THE WEAK BOUNDARY...HIGH AMOUNT OF
NEAR-SURFACE MOISTURE...RELATIVELY CLEAR SKIES AND LIGHT WINDS
...FOG IS DEVELOPING ACROSS THE REGION. WITH THESE FACTORS IN
PLACE...WILL CONTINUE TO MONITOR CLOSELY FOR FORMATION OF DENSE FOG
(AND THE NEED FOR A DENSE FOG ADVISORY).

AS THE MIDLEVEL SHORTWAVE ENERGY ACROSS THE UPPER MIDWEST LIFTS
NORTHEAST...WARM ADVECTION SHOULD ALLOW THE WEAK BOUNDARY TO MAKE
MOVEMENT TO THE NORTH. SCATTERED THUNDERSTORMS ARE ANTICIPATED AS A
RESULT...WITH NO ADDITIONAL ORGANIZATION SUPPORT SEEN IN THE MID OR
UPPER LEVELS.

THE ENVIRONMENT WILL BECOME A BIT MORE SUPPORTIVE OF ORGANIZED
SEVERE WEATHER LATE THIS AFTERNOON INTO THIS EVENING...ALTHOUGH WITH
STORM MOTIONS OF 5-10KT AND PRECIPITABLE WATER VALUES NEAR
1.5...LOCALLY HEAVY RAIN WILL BE THE MAIN THREAT. AS THE UPPER
LEVEL JET STRENGTHENS ACROSS THE UPPER GREAT LAKES THIS
AFTERNOON...OUR LOW LEVEL WIND FIELDS INCREASE...WITHIN A LOW TO
MODERATELY UNSTABLE ENVIRONMENT (MLCAPE OF 1000-2000 J/KG SEEN ON
BUFKIT FORECAST SOUNDINGS). HELCITY VALUES INCREASE BY LATE
AFTERNOON ENOUGH TO SUPPORT STORM ROTATION...WHILE SHEAR VALUES
SUGGEST STORMS WILL ORGANIZE INTO MULTICELL CLUSTERS...INCREASING
THE THREAT FOR AREAS OF HEAVY RAIN. SOME UPDRAFT ROTATION IS
ANTICIPATED...WITH LOW LCLS NOTED...ESPECIALLY IN THE VICINITY OF
THE ADVANCING WARM FRONT. WITH WET-BULB ZERO VALUES NEAR 9KFT AND
NCAPE VALUES NEARING .20 M/S2...STRONGEST UPDRAFTS WITH SUSTAINED
CORES ABOVE 20KFT MAY SUPPORT HAIL FORMATION.

THIS ACTIVITY IS EXPECTED TO WANE FROM SOUTH TO NORTH THIS
EVENING...AS THE BOUNDARY PUSHES NORTHEAST OF THE FORECAST AREA.
SUSTAINED SOUTHERLY WINDS IN THE WARM SECTOR SHOULD PRECLUDE
DEVELOPMENT OF DENSE FOG...WHILE CONVECTIVELY INDUCED CLOUDINESS
DECREASES OVERNIGHT.

ROGOWSKI

&&

.LONG TERM (TUE-SUN)
THE REGION GOES QUICKLY BACK INTO A WARM JUICY UNSTABLE AIR MASS
TUE. THE NEXT FRONTAL BOUNDARY LOOKS TO AFFECT OUR FA TUE NIGHT AND
IS PROGGED TO STALL ACROSS THE MID ATLANTIC WED. STILL LOOKS
POSSIBLE FOR A CONVECTIVE COMPLEX TO RIDE SOUTHEAST ALONG THE
BOUNDARY LATE TUESDAY NIGHT INTO WEDNESDAY AND HAVE RAISED POPS A
BIT DURING THIS PERIOD. THE FRONT LOOKS TO LIFT BACK NORTH ON
THURSDAY. OVER ALL...CONTINUED WARM TEMPS WI A SCHC/CHC OF
CONVECTION EACH DAY. ND

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-
050>057-WVZ048>055-010000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
432 AM EDT MON MAY 17 2004

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-
050>057-WVZ048>055-181000-
ALBEMARLE VA-ALLEGANY MD-ANNE ARUNDEL MD-
ARLINGTON/FALLS CHURCH/ALEXANDRIA VA-AUGUSTA VA-BERKELEY WV-
CALVERT MD-CARROLL MD-CHARLES MD-CLARKE VA-CULPEPER VA-
DISTRICT OF COLUMBIA DC-FAIRFAX VA-FAUQUIER VA-FREDERICK VA-
FREDERICK MD-GRANT WV-GREENE VA-HAMPSHIRE WV-HARDY WV-HARFORD MD-
HIGHLAND VA-HOWARD MD-JEFFERSON WV-KING GEORGE VA-LOUDOUN VA-
MADISON VA-MINERAL WV-MONTGOMERY MD-MORGAN WV-NELSON VA-
NORTHERN BALTIMORE MD-ORANGE VA-PAGE VA-PENDLETON WV-
PRINCE GEORGES MD-PRINCE WILLIAM/MANASSAS/MANASSAS PARK VA-
RAPPAHANNOCK VA-ROCKINGHAM VA-SHENANDOAH VA-SOUTHERN BALTIMORE MD-
SPOTSYLVANIA VA-ST. MARYS MD-STAFFORD VA-WARREN VA-WASHINGTON MD-
432 AM EDT MON MAY 17 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MARYLAND WEST OF THE CHESAPEAKE
BAY AND EAST OF GARRETT COUNTY...EASTERN WEST VIRGINIA...NORTHERN AND
CENTRAL VIRGINIA AND WASHINGTON DC.

.DAY ONE...
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND
EVENING. HEAVY RAINFALL WILL BE THE GREATEST THREAT. HOWEVER...A FEW
STORMS COULD BECOME STRONG AND MAY PRODUCE GUSTY WINDS AND HAIL.

.DAYS TWO THROUGH SEVEN...
ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE EACH DAY.

 .SPOTTER INFORMATION STATEMENT...
PRECIPITATION AND OTHER SEVERE WEATHER REPORTS WILL BE APPRECIATED
THIS AFTERNOON AND EVENING. HOWEVER...SKYWARN ACTIVATION IS NOT
ANTICIPATED AT THIS TIME.

ROGOWSKI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1227 PM EDT MON MAY 17 2004

VAZ025-026-036>038-171730-
ALBEMARLE VA-AUGUSTA VA-GREENE VA-NELSON VA-ROCKINGHAM VA-
1227 PM EDT MON MAY 17 2004

...THUNDERSTORMS RAPIDLY DEVELOPING ON THE BLUE RIDGE...

AT 1225 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS RAPIDLY DEVELOPING ALONG THE BLUE RIDGE BETWEEN AUGUSTA
AND NELSON COUNTIES. THESE STORMS WILL DRIFT SLOWLY TO THE NORTHEAST.

THUNDERSTORMS WILL BECOME STRONGER AND MORE NUMEROUS THROUGH MID
AFTERNOON.

VERY HEAVY RAINFALL...SMALL HAIL AND STRONG GUSTY WINDS WILL BE THE
MAIN THREATS FROM THIS ACTIVITY. RESIDENTS IN THE CENTRAL SHENANDOAH
VALLEY SHOULD REMAIN ALERT AND BE PREPARED TO TAKE ACTION IF WARNINGS
ARE ISSUED OR IF THREATENING WEATHER APPROACHES.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

MANNING

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1259 PM EDT MON MAY 17 2004

VAZ025-026-036>038-171800-
ALBEMARLE VA-AUGUSTA VA-GREENE VA-NELSON VA-ROCKINGHAM VA-
1259 PM EDT MON MAY 17 2004

...THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL ALONG THE BLUE
RIDGE...

AT 155 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL ALONG THE BLUE RIDGE IN
AUGUSTA AND NELSON COUNTIES. THESE STORMS WERE NEARLY STATIONARY.
THUNDERSTORMS WILL BECOME STRONGER AND MORE NUMEROUS THROUGH MID
AFTERNOON.

TORRENTIAL RAINFALL IN EXCESS OF 1 TO 2 INCHES...SMALL HAIL AND
STRONG GUSTY WINDS WILL BE THE MAIN THREATS FROM THIS ACTIVITY.
RESIDENTS IN THE CENTRAL SHENANDOAH VALLEY SHOULD REMAIN ALERT AND BE
PREPARED TO TAKE ACTION IF WARNINGS ARE ISSUED OR IF THREATENING
WEATHER APPROACHES. NEVER STAY IN AREAS SUBJECT TO FLOODING DURING
PERIODS OF TORRENTIAL RAINFALL OR IF WATER BEGINS TO RISE.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

MANNING

SPECIAL WEATHER STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1259 PM EDT MON MAY 17 2004

VAZ025-026-036>038-171800-
ALBEMARLE VA-AUGUSTA VA-GREENE VA-NELSON VA-ROCKINGHAM VA-
1259 PM EDT MON MAY 17 2004

...THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL ALONG THE BLUE
RIDGE...

AT 1255 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS PRODUCING TORRENTIAL RAINFALL ALONG THE BLUE RIDGE IN
AUGUSTA AND NELSON COUNTIES. THESE STORMS WERE NEARLY STATIONARY.
THUNDERSTORMS WILL BECOME STRONGER AND MORE NUMEROUS THROUGH MID
AFTERNOON.

TORRENTIAL RAINFALL IN EXCESS OF 1 TO 2 INCHES...SMALL HAIL AND
STRONG GUSTY WINDS WILL BE THE MAIN THREATS FROM THIS ACTIVITY.
RESIDENTS IN THE CENTRAL SHENANDOAH VALLEY SHOULD REMAIN ALERT AND BE
PREPARED TO TAKE ACTION IF WARNINGS ARE ISSUED OR IF THREATENING
WEATHER APPROACHES. NEVER STAY IN AREAS SUBJECT TO FLOODING DURING
PERIODS OF TORRENTIAL RAINFALL OR IF WATER BEGINS TO RISE.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

MANNING