Storm Prediction Center Severe Thunderstorm Watch 643

Note: 
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for Watch Status Reports.

   SEL3

   URGENT - IMMEDIATE BROADCAST REQUESTED
   Severe Thunderstorm Watch Number 643
   NWS Storm Prediction Center Norman OK
   1140 AM EDT Wed Sep 2 2026

   The NWS Storm Prediction Center has issued a

   * Severe Thunderstorm Watch for portions of 
     District Of Columbia
     Maryland
     Northern Virginia
     The Eastern West Virginia Panhandle
     Coastal Waters

   * Effective this Wednesday morning and afternoon from 1140 AM
     until 500 PM EDT.

   * Primary threats include...
     Scattered damaging wind gusts to 70 mph possible
     Isolated large hail events to 1.5 inches in diameter possible

   SUMMARY...A well-organized thunderstorm cluster should continue to
   pose some threat for scattered damaging winds as it moves quickly
   southeastward this afternoon. Occasional hail may also occur with
   the strongest cores.

   The severe thunderstorm watch area is approximately along and 65
   statute miles east and west of a line from 5 miles east northeast of
   Hagerstown MD to 40 miles south southwest of Washington DC. For a
   complete depiction of the watch see the associated watch outline
   update (WOUS64 KWNS WOU3).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Severe Thunderstorm Watch means conditions are
   favorable for severe thunderstorms in and close to the watch area.
   Persons in these areas should be on the lookout for threatening
   weather conditions and listen for later statements and possible
   warnings. Severe thunderstorms can and occasionally do produce
   tornadoes.

   &&

   OTHER WATCH INFORMATION...CONTINUE...WW 642...

   AVIATION...A few severe thunderstorms with hail surface and aloft to
   1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
   few cumulonimbi with maximum tops to 550. Mean storm motion vector
   32040.

   ...Gleason

Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.

   SAW3 
   WW 643 SEVERE TSTM DC MD VA WV CW 021540Z - 022100Z
   AXIS..65 STATUTE MILES EAST AND WEST OF LINE..
   5ENE HGR/HAGERSTOWN MD/ - 40SSW DCA/WASHINGTON DC/
   ..AVIATION COORDS.. 55NM E/W /33WNW EMI - 33SE CSN/
   HAIL SURFACE AND ALOFT..1.5 INCHES. WIND GUSTS..60 KNOTS.
   MAX TOPS TO 550. MEAN STORM MOTION VECTOR 32040.

   LAT...LON 39727641 38317611 38317851 39727886

   THIS IS AN APPROXIMATION TO THE WATCH AREA.  FOR A
   COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
   FOR WOU3.

Watch 643 Status Report Message has not been issued yet.

Note:
 Click for Complete Product Text.

Tornadoes

Wind

Hail

Combined Severe Hail/Wind

For each watch, probabilities for particular events inside the watch
(listed above in each table) are determined by the issuing forecaster.
The “Low” category contains probability values ranging from less than 2%
to 20% (EF2-EF5 tornadoes), less than 5% to 20% (all other probabilities),
“Moderate” from 30% to 60%, and “High” from 70% to greater than 95%.
High values are bolded and lighter in color to provide awareness of
an increased threat for a particular event.