Alert archive / Virginia / Mesoscale Discussions in 2012
Mesoscale Discussion 1892
The Storm Prediction Center issued this mesoscale discussion at Sep 5, 2012, 2:12 PM EDT for 7 states. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Sep 5, 2012, 2:12 PM EDT (18:12 UTC)
- Expired
- Sep 5, 2012, 3:15 PM EDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 43 counties
Kent County, DE, New Castle County, DE, Dukes County, MA, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Charles County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Talbot County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Suffolk County, NY, Newport County, RI, Washington County, RI, Albemarle County, VA, Arlington 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, City of Staunton, VA, City of Waynesboro, VA, Culpeper County, VA, Fairfax County, VA, Greene County, VA, King George County, VA, Louisa County, VA, Madison County, VA, Orange County, VA, Prince William County, VA, Spotsylvania County, VA, Stafford County, VA
The radar
The Philadelphia radar (KDIX), 78 km from the middle of the area, began a volume at 18:12 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
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.2 hours before the alert went out and 81 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
- 950 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 672 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 81 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
886
ACUS11 KWNS 051813
SWOMCD
SPC MCD 051812
MAZ000-RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-051915-
MESOSCALE DISCUSSION 1892
NWS STORM PREDICTION CENTER NORMAN OK
0112 PM CDT WED SEP 05 2012
AREAS AFFECTED...UPPER MID ATLANTIC INTO SRN NEW ENGLAND
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 051812Z - 051915Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...ISOLD INSTANCES OF DMGG WIND MAY OCCUR AS THUNDERSTORMS
CONTINUE TO INCREASE IN COVERAGE THIS AFTERNOON. HOWEVER...A WW IS
NOT ANTICIPATED.
DISCUSSION...DESPITE MARGINAL INSTABILITY...THUNDERSTORMS CONTINUE
TO DEVELOP IN RESPONSE TO FORCING FOR ASCENT WITH AN APPROACHING
UPPER SHORT WAVE AND A SEWD PROGRESSING COLD FRONT. THUS FAR...WEAK
INSTABILITY APPEARS TO BE LIMITING STRONGER UPDRAFTS...EVIDENCED BY
QUICKLY COLLAPSING CORES. MODEST UNIDIRECTIONAL FLOW ACROSS SRN NEW
ENGLAND MAY ENHANCE THE POTENTIAL OF A FEW SMALL/BRIEF-LIVED
CLUSTERS OF STORMS WITH FASTER LOW-LEVEL WINDS TRANSLATING TO THE
SURFACE. TO THE S...WEAKER FLOW BUT MARGINALLY GREATER INSTABILITY
MAY LEAD TO A FEW PULSE STORMS...WITH A DEEPLY SATURATED AIR MASS
CHARACTERIZED BY PWAT VALUES AOA 2 INCH CONTRIBUTING TO
PRECIPITATION LOADING AND RESULTING IN GUSTY SURFACE WINDS.
..HURLBUT/CORFIDI.. 09/05/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BOX...OKX...PHI...AKQ...LWX...
LAT...LON 38147919 38427858 39627573 41137233 41867052 41477015
40927141 39427423 38177668 37747880 38147919Nearby
Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in Maryland, 2012Mesoscale Discussions in New Jersey, 2012Every mesoscale discussion in 2012
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.