Alert archive / Maryland / Severe Thunderstorm Watches in 2004
Severe Thunderstorm Watch 710
The Storm Prediction Center issued this severe thunderstorm watch at Aug 4, 2004, 7:10 PM EDT for 5 states. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 4, 2004, 7:10 PM EDT (23:10 UTC)
- Expired
- Aug 4, 2004, 11:00 PM EDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
All 32 counties
Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Caroline County, MD, Cecil County, MD, City of Baltimore, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Talbot County, MD, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Lancaster County, PA, Montgomery County, PA, Philadelphia County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Manassas, VA, City of Manassas Park, VA, Fairfax County, VA, Prince William County, VA
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 7:13 PM EDT | Tornado Warning | CTP | Lancaster | 47 min |
| Aug 4, 7:24 PM EDT | Severe Thunderstorm Warning | LWX | Harford | 66 min |
| Aug 4, 7:35 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Prince George's, City of Baltimore | 55 min |
| Aug 4, 7:49 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 56 min |
| Aug 4, 7:54 PM EDT | Severe Thunderstorm Warning | PHI | Kent | 51 min |
| Aug 4, 8:08 PM EDT | Tornado Warning | PHI | New Castle | 22 min |
| Aug 4, 8:18 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Camden, Gloucester, Salem | 57 min |
| Aug 4, 8:25 PM EDT | Severe Thunderstorm Warning | PHI | Queen Anne's | 35 min |
| Aug 4, 8:35 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Talbot | 55 min |
| Aug 4, 9:11 PM EDT | Severe Thunderstorm Warning | PHI | Kent | 49 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 11.2 hours before the alert went out and 116 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 24 J/kg
- Mixed-layer CIN
- -92 J/kg
- Mixed-layer LCL
- 1125 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- -2 m²/s²
- 0-3 km storm-relative helicity
- -4 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
WWUS20 KWNS 042309
SEL0
SPC WW 042310
DCZ000-DEZ000-MDZ000-NJZ000-PAZ000-VAZ000-CWZ000-050300-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 710
NWS STORM PREDICTION CENTER NORMAN OK
710 PM EDT WED AUG 4 2004
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
DISTRICT OF COLUMBIA
DELAWARE
NORTHERN MARYLAND
SOUTHERN NEW JERSEY
SOUTHEASTERN PENNSYLVANIA
FAR NORTHERN VIRGINIA
COASTAL WATERS
EFFECTIVE THIS WEDNESDAY EVENING FROM 710 PM UNTIL 1100 PM EDT.
HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 60 STATUTE MILES
EAST AND WEST OF A LINE FROM 30 MILES NORTH NORTHEAST OF
PHILADELPHIA PENNSYLVANIA TO 30 MILES EAST SOUTHEAST OF WASHINGTON
DISTRICT OF COLUM.
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 707...WW 708...WW 709...
DISCUSSION...LINE OF STORMS HAS INTENSIFIED INTO WRN PORTIONS OF WW
IN THE PAST HOUR. THREAT OF WIND DAMAGE WILL LIKELY OVERSPREAD THE
REGION AS DEEP CONVERGENCE SHIFTS EWD ALONG NORTHERN PERIPHERY OF
MODERATE INSTABILITY NOW IN PLACE OVER CENTRAL VA.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.
A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION
VECTOR 28035.
...EVANS
401,0735 384,0752 384,0773 401,0760SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 5:48 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle | 117 min |
| Aug 4, 2:31 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett, Washington | 119 min |
| Aug 4, 2:55 PM EDT | Severe Thunderstorm Watch | SPC | Allegany, Carroll, Frederick, Garrett, Washington | 6 hr |
| Aug 4, 10:39 AM EDT | Mesoscale Discussion | SPC | Allegheny, Beaver, Fayette, Greene, Washington, Westmoreland | 2 hr |
| Aug 4, 11:55 AM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 8 more | 5 hr |
| Aug 4, 2:30 PM EDT | Severe Thunderstorm Watch | SPC | Bland, Buchanan, Dickenson, Tazewell, Wise | 6 hr |
| Aug 4, 4:39 PM EDT | Mesoscale Discussion | SPC | Buchanan, Dickenson, Russell, Tazewell, Wise, City of Norton | 96 min |
Nearby
Severe Thunderstorm Watches in Maryland, 2004Severe Thunderstorm Watches in Virginia, 2004Severe Thunderstorm Watches in New Jersey, 2004Every severe thunderstorm watch in 2004
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.