Alert archive / Virginia / Mesoscale Discussions in 2004

Mesoscale Discussion 2274

September 28, 20044 states

The Storm Prediction Center issued this mesoscale discussion at Sep 28, 2004, 8:56 AM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 28, 2004, 8:56 AM EDT (12:56 UTC)
Expired
Sep 28, 2004, 11:00 AM EDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Sussex County, DE, Dorchester County, MD, Somerset County, MD, Wicomico County, MD, Worcester County, MD, Camden County, NC, Currituck County, NC, Pasquotank County, NC, Tyrrell County, NC, Accomack County, VA, City of Norfolk, VA, City of Virginia Beach, VA, Mathews County, VA, Northampton County, VA, Northumberland County, VA

The radar

The Norfolk radar (KAKQ), 100 km from the middle of the area, began a volume at 13:00 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 0.9 hours before the alert went out and 87 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.

Skew-T log-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2004-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1005 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2004-09-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1005 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
483 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 28, 1:49 PM EDTMesoscale DiscussionSPCKent, New Castle, Sussex116 min
Sep 28, 2:25 PM EDTTornado WatchSPCKent, New Castle, Sussex7 hr
Sep 28, 4:36 PM EDTMesoscale DiscussionSPCKent, New Castle, Sussex114 min
Sep 28, 11:25 AM EDTTornado WatchSPCCalvert, Charles, Dorchester, Saint Mary's, Somerset, Wicomico and 1 more6 hr
Sep 27, 9:10 PM EDTTornado WatchSPCAnson, Bladen, Brunswick, Chatham, Columbus, Cumberland and 15 more7 hr
Sep 28, 12:46 AM EDTMesoscale DiscussionSPCAnson, Bladen, Brunswick, Cabarrus, Chatham, Columbus and 16 more89 min
Sep 28, 2:59 AM EDTMesoscale DiscussionSPCChatham, Cumberland, Durham, Harnett, Johnston, Lee and 5 more2 hr

Nearby

Mesoscale Discussions in Virginia, 2004Mesoscale Discussions in Maryland, 2004Mesoscale Discussions in North Carolina, 2004Every mesoscale discussion 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; radar from the NEXRAD Level II archive.