Alert archive / Virginia / Mesoscale Discussions in 2003

Mesoscale Discussion 1739

July 9, 200310 counties in Maryland; 65 counties in Virginia; 20 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2003, 2:47 PM EDT for 10 counties in Maryland; 65 counties in Virginia; 20 counties in West Virginia. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
Jul 9, 2003, 2:47 PM EDT (18:47 UTC)
Expired
Jul 9, 2003, 4:15 PM EDT
In force
88 min
Issued by
the Storm Prediction Center
All 95 counties

Allegany County, MD, Baltimore County, MD, Carroll County, MD, City of Baltimore, MD, Frederick County, MD, Garrett County, MD, Harford County, MD, Howard County, MD, Montgomery County, MD, Washington County, MD, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buchanan County, VA, Campbell County, VA, Carroll County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Fairfax, VA, City of Falls Church, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Norton, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Culpeper County, VA, Dickenson County, VA, Fairfax County, VA, Fauquier County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Frederick County, VA, Giles County, VA, Greene County, VA, Highland County, VA, Lee County, VA, Loudoun County, VA, Madison County, VA, Montgomery County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Pulaski County, VA, Rappahannock County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Russell County, VA, Scott County, VA, Shenandoah County, VA, Smyth County, VA, Tazewell County, VA, Warren County, VA, Washington County, VA, Wise County, VA, Wythe County, VA, Barbour County, WV, Berkeley County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, McDowell County, WV, Mercer County, WV, Mineral County, WV, Monroe County, WV, Morgan County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Summers County, WV, Tucker County, WV, Webster County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 78 km from the middle of the area, began a volume at 18:50 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

Roanoke, VA (KRNK), launched 12:00Z, 6.8 hours before the alert went out and 109 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, Roanoke, VA at 12:00Z on 2003-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1142 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, Roanoke, VA at 12:00Z on 2003-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.1939Sfc1 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
1142 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
646 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

933 
ACUS11 KWNS 091847
SWOMCD
SPC MCD 091847 
MDZ000-DCZ000-VAZ000-WVZ000-KYZ000-TNZ000-092015-

MESOSCALE DISCUSSION 1739
NWS STORM PREDICTION CENTER NORMAN OK
0147 PM CDT WED JUL 09 2003

AREAS AFFECTED...ERN WV...NRN AND WRN MD...NRN/WRN/SWRN VA

CONCERNING...SEVERE THUNDERSTORM WATCH 695...

VALID 091847Z - 092015Z

ACROSS WW 695...AN ORGANIZED LINE OF THUNDERSTORMS EXTENDS AT 1835Z
FROM THE NERN WV PANHANDLE SSWWD TO 10W ROA BEFORE ARCING WWD ACROSS
FAR SWRN SECTIONS OF VA. STRONG COLD POOL IN ASSOCIATION WITH THIS
LINE IN ADDITION TO MODERATE DEEP-LAYER WLY SHEAR SHOULD STEER THE
LINE EWD AT 30-35KT. ENVIRONMENT REMAINS MODERATELY UNSTABLE IN
ADVANCE OF ONGOING CONVECTION WITH 100MB MLCAPE VALUES OF 1000-1500
J/KG ACROSS WRN VA. EMBEDDED SMALL-SCALE BOWS WILL HAVE AN ENHANCED
POTENTIAL FOR DAMAGING WIND GUSTS DURING THE NEXT FEW HOURS.
ADDITION CONVECTION DEVELOPING IN LYH VICINITY MAY ALSO BECOME
SEVERE DURING THE NEXT HOUR OR SO.  

AT THE SRN END OF THE CONVECTIVE LINE...STORMS HAVE ATTAINED AN E-W
ORIENTATION ...RESULTING IN TRAINING ECHOES AND INCREASED HEAVY RAIN
POTENTIAL ACROSS SCOTT...RUSSELL...WASHINGTON...AND SMYTH COUNTIES
IN SWRN VA. SEVERE THUNDERSTORM POTENTIAL IN THIS AREA WILL LIKELY
DECREASE IN FAVOR OF HEAVY RAINFALL...AND AN ADDITIONAL WATCH IS NOT
ANTICIPATED IN ADJACENT AREAS OF FAR NERN TN/NRN NC. 

ISOLATED CONVECTION CONTINUES ACROSS N-CENTRAL SECTIONS OF VA.
SEVERE THUNDERSTORM OVER LOUDOUN COUNTY VA WILL PASS NEAR DULLES
AIRPORT AT 1915Z AND THE SOUTH SIDE OF WASHINGTON D.C. BETWEEN 1930Z
AND 2000Z BASED ON PRESENT TRENDS.

..BANACOS.. 07/09/2003

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...AKQ...LWX...RNK...PBZ...RLX...MRX...JKL...

36598343 37258260 37748128 39647956 39667592 38257773
36717967 36688162

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 8, 8:12 PM EDTMesoscale DiscussionSPCAllegany, Carroll, Frederick, Garrett, Howard, Montgomery and 1 more93 min
Jul 8, 8:30 PM EDTSevere Thunderstorm WatchSPCAllegany, Frederick, Garrett, Washington4 hr
Jul 8, 11:16 PM EDTMesoscale DiscussionSPCAllegany119 min
Jul 9, 10:28 AM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Carroll, Cecil, Charles and 9 more92 min
Jul 9, 11:50 AM EDTSevere Thunderstorm WatchSPCAllegany, Anne Arundel, Baltimore, Carroll, Cecil, Frederick and 7 more6 hr
Jul 9, 12:09 PM EDTMesoscale DiscussionSPCCalvert, Caroline, Charles, Dorchester, Kent, Queen Anne's and 5 more96 min
Jul 9, 1:15 PM EDTSevere Thunderstorm WatchSPCAnne Arundel, Calvert, Caroline, Cecil, Charles, Dorchester and 8 more8 hr
Jul 9, 3:48 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Caroline, Charles, Dorchester, Kent and 7 more117 min
Jul 9, 7:36 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Caroline, Cecil, Charles, Dorchester and 8 more114 min
Jul 9, 12:55 PM EDTMesoscale DiscussionSPCWise3 hr

Nearby

Mesoscale Discussions in Virginia, 2003Mesoscale Discussions in West Virginia, 2003Mesoscale Discussions in Maryland, 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.