Alert archive / Virginia / Mesoscale Discussions in 2019

Mesoscale Discussion 2135

October 31, 20196 states

The Storm Prediction Center issued this mesoscale discussion at Oct 31, 2019, 7:14 PM EDT for 6 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Oct 31, 2019, 7:14 PM EDT (23:14 UTC)
Expired
Oct 31, 2019, 9:15 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
All 61 counties

New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, 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, Washington County, MD, Hunterdon County, NJ, Salem County, NJ, Warren County, NJ, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Northumberland County, PA, Philadelphia County, PA, Schuylkill County, PA, York County, PA, Arlington County, VA, Caroline County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Manassas, VA, City of Manassas Park, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, King George County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Orange County, VA, Prince William County, VA, Rappahannock County, VA, Spotsylvania County, VA, Stafford County, VA, Jefferson County, WV

The radar

The Sterling radar (KLWX), 48 km from the middle of the area, began a volume at 23:19 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.2 hours before the alert went out and 43 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, Washington/Dulle, VA at 12:00Z on 2019-10-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2019-10-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 280 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
489 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
280 m²/s²
0-3 km storm-relative helicity
246 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 31, 7:56 PM EDTSevere Thunderstorm WatchSPCKent, New Castle6 hr
Oct 31, 11:12 AM EDTMesoscale DiscussionSPCGarrett2 hr
Oct 31, 1:11 PM EDTMesoscale DiscussionSPCAllegany, Frederick, Montgomery, Washington3 hr
Oct 31, 2:56 PM EDTTornado WatchSPCAllegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 9 more10 hr
Oct 31, 4:01 PM EDTMesoscale DiscussionSPCBaltimore, Carroll, Frederick, Howard, Montgomery, Washington and 1 more119 min
Oct 31, 4:46 PM EDTMesoscale DiscussionSPCPassaic, Sussex119 min
Oct 31, 6:16 PM EDTSevere Thunderstorm WatchSPCBradford, Lackawanna, Luzerne, Pike, Susquehanna, Wayne and 1 more8 hr
Oct 31, 12:45 PM EDTTornado WatchSPCBland, Buchanan, Dickenson, Giles, Grayson, Pulaski and 10 more4 hr
Oct 31, 3:16 PM EDTTornado WatchSPCAlleghany, Amelia, Amherst, Appomattox, Bath, Bedford and 56 more8 hr
Oct 31, 6:36 PM EDTMesoscale DiscussionSPCAmelia, Appomattox, Brunswick, Buckingham, Campbell, Charles City and 32 more114 min

Nearby

Mesoscale Discussions in Virginia, 2019Mesoscale Discussions in Pennsylvania, 2019Mesoscale Discussions in Maryland, 2019Every mesoscale discussion in 2019

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.