Alert archive / Virginia / Mesoscale Discussions in 2021
Mesoscale Discussion 76
The Storm Prediction Center issued this mesoscale discussion at Feb 13, 2021, 10:02 AM EST for 5 states. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 13, 2021, 10:02 AM EST (15:02 UTC)
- Expired
- Feb 13, 2021, 4:00 PM EST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Freezing rain
All 99 counties
Kent County, DE, New Castle County, DE, Sussex County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Wicomico County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Salem County, NJ, Delaware County, PA, Philadelphia County, PA, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, City of Roanoke, VA, City of Staunton, VA, City of Waynesboro, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockbridge County, VA, Rockingham County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA
The radar
The Sterling radar (KLWX), 67 km from the middle of the area, began a volume at 15:07 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, 3.0 hours before the alert went out and 62 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 724 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 121 m²/s²
- 0-3 km storm-relative helicity
- 314 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
662
ACUS11 KWNS 131503
SWOMCD
SPC MCD 131502
NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-WVZ000-132100-
Mesoscale Discussion 0076
NWS Storm Prediction Center Norman OK
0902 AM CST Sat Feb 13 2021
Areas affected...portions of the Mid-Atlantic
Concerning...Freezing rain
Valid 131502Z - 132100Z
SUMMARY...Areas of freezing rain and occasional sleet will impact
much of the Mid-Atlantic through early afternoon.
DISCUSSION...A broad area of ascent/isentropic lift atop a shallow
cold airmass continues to contribute to widespread freezing rain at
this time. The freezing rain is reportedly mixing with sleet at
times across the DC/Baltimore MD areas, though a transition to more
freezing rain should occur in that area over time as models indicate
warm advection in the H7-H85 layer. Precipitation rates may
approach 0.05 inch/hour at times beneath heavier precipitation
bands. The general regime should persist through early afternoon,
with a general northeastward expansion of the precipitation shield
toward Delaware/southern New Jersey and the Philadelphia area over
the next couple hours or so. Several models/CAMs shift
precipitation out of much of Virginia and western Maryland around
21Z.
..Cook.. 02/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...
LAT...LON 39087815 39347734 39967564 40067489 39757443 39527439
39407450 38747502 37587660 36827786 36617874 36767934
36957986 37308004 37827988 39087815SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 13, 2:21 AM EST | Mesoscale Discussion | SPC | Amelia, Amherst, Appomattox, Bedford, Bland, Botetourt and 56 more | 6 hr |
Nearby
Mesoscale Discussions in Virginia, 2021Mesoscale Discussions in Maryland, 2021Mesoscale Discussions in New Jersey, 2021Every mesoscale discussion in 2021
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.