Alert archive / Virginia / Mesoscale Discussions in 2003
Mesoscale Discussion 1521
The Storm Prediction Center issued this mesoscale discussion at Jun 27, 2003, 1:45 PM EDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 27, 2003, 1:45 PM EDT (17:45 UTC)
- Expired
- Jun 27, 2003, 3:45 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 39 counties
Sussex County, DE, Calvert County, MD, Charles County, MD, Dorchester County, MD, Saint Mary's County, MD, Somerset County, MD, Wicomico County, MD, Worcester County, MD, Caswell County, NC, Rockingham County, NC, Amelia County, VA, Appomattox County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charlotte County, VA, Chesterfield County, VA, City of Danville, VA, City of Fredericksburg, VA, City of Martinsville, VA, City of Richmond, VA, Cumberland County, VA, Essex County, VA, Goochland County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lunenburg County, VA, Northumberland County, VA, Nottoway County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Richmond County, VA, Westmoreland County, VA
The radar
The Norfolk radar (KAKQ), 81 km from the middle of the area, began a volume at 17:44 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 nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 5.8 hours before the alert went out and 153 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
- 311 J/kg
- Mixed-layer CIN
- -92 J/kg
- Mixed-layer LCL
- 1424 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- -98 m²/s²
- 0-3 km storm-relative helicity
- 10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.2
The text
As transmitted, in the capitals the NWS used until 2016.
631 ACUS11 KWNS 271746 SWOMCD SPC MCD 271745 DEZ000-MDZ000-VAZ000-NCZ000-271945- MESOSCALE DISCUSSION 1521 NWS STORM PREDICTION CENTER NORMAN OK 1245 PM CDT FRI JUN 27 2003 AREAS AFFECTED...NRN NC...CNTRL/ERN VA...DELMARVA PEN CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 271745Z - 271945Z WW IS NOT CURRENTLY ANTICIPATED...BUT TRENDS ARE BEING MONITORED. SURFACE FRONT IS ADVANCING INTO/THROUGH THE PHILADELPHIA/WASHINGTON D.C. AREAS...AND BEGINNING TO SHIFT EAST OF THE MOUNTAINS OF WESTERN VIRGINIA AND NORTH CAROLINA...WHERE SCATTERED CONVECTIVE DEVELOPMENT IS ALREADY UNDERWAY. AS FRONT CONTINUES SLOWLY SOUTHEASTWARD THIS AFTERNOON...MODELS SUGGEST FORCING FOR UPWARD VERTICAL MOTION WILL INCREASE EAST OF CHARLOTTESVILLE VA INTO THE SALISBURY MD AREA... WHERE SURFACE TEMPERATURES NEAR 90F ARE CONTRIBUTING TO MODERATELY STRONG POTENTIAL INSTABILITY. MEAN MIXED LAYER CAPE IN EXCESS OF 2000 J/KG WILL SUPPORT VIGOROUS UPDRAFTS WITH VERY HEAVY DOWNPOURS. DESPITE WEAK FLOW/SHEAR REGIME...SOME MARGINALLY SEVERE HAIL IS POSSIBLE...BUT PRIMARY SEVERE THREAT APPEARS TO BE ISOLATED DAMAGING DOWNBURSTS...WITH DRY MID-LEVEL AIR ENHANCING EVAPORATIVE COOLING IN DOWDRAFTS. ..KERR.. 06/27/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PHI...AKQ...LWX...RAH...RNK... 38117530 37617679 37337746 36747849 36187949 36128019 36688014 37457883 38137769 38507729 38777576 38837519
Nearby
Mesoscale Discussions in Virginia, 2003Mesoscale Discussions in Maryland, 2003Mesoscale Discussions in North Carolina, 2003Every mesoscale discussion in 2003
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.