Alert archive / West Virginia / Mesoscale Discussions in 2003

Mesoscale Discussion 1685

July 7, 200321 counties in Ohio; 18 counties in Pennsylvania; 28 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2003, 6:52 PM EDT for 21 counties in Ohio; 18 counties in Pennsylvania; 28 counties in West Virginia. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Jul 7, 2003, 6:52 PM EDT (22:52 UTC)
Expired
Jul 7, 2003, 7:45 PM EDT
In force
53 min
Issued by
the Storm Prediction Center
All 67 counties

Athens County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Gallia County, OH, Geauga County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Lake County, OH, Mahoning County, OH, Meigs County, OH, Monroe County, OH, Morgan County, OH, Muskingum County, OH, Noble County, OH, Portage County, OH, Stark County, OH, Trumbull County, OH, Tuscarawas County, OH, Washington County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Cameron County, PA, Clarion County, PA, Crawford County, PA, Elk County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Braxton County, WV, Brooke County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Gilmer County, WV, Hancock County, WV, Harrison County, WV, Jackson County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mason County, WV, Monongalia County, WV, Nicholas County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tyler County, WV, Upshur County, WV, Webster County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV

The radar

The Pittsburgh radar (KPBZ), 98 km from the middle of the area, began a volume at 22:52 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

Pittsburgh, PA (KPIT), launched 12:00Z, 10.9 hours before the alert went out and 96 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, Pittsburgh, PA at 12:00Z on 2003-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 202 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, Pittsburgh, PA at 12:00Z on 2003-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.193958Sfc1 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
202 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
648 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

813 
ACUS11 KWNS 072252
SWOMCD
SPC MCD 072252 
PAZ000-MDZ000-WVZ000-OHZ000-072345-

MESOSCALE DISCUSSION 1685
NWS STORM PREDICTION CENTER NORMAN OK
0552 PM CDT MON JUL 07 2003

AREAS AFFECTED...ERN OH/WRN PA/WRN...NWRN WV

CONCERNING...SEVERE THUNDERSTORM WATCH 668...

VALID 072252Z - 072345Z

WEAKENING MCS CONTINUES TO MOVE ESEWD THRU PORTIONS OF SWRN OH INTO
SERN PA AND WRN/NWRN WV. WW 668 WILL REMAIN IN EFFECT THRU
08/01Z...ALTHOUGH THE SEVERE THREAT APPEARS TO BE ON THE DECREASE IN
MOST OF THESE AREAS. 

MOST RECENT RADAR/SATELLITE IMAGERY SHOWS A WEAKENING MCS FROM NORTH
OF LATROBE SSWWD TO AROUND GALLIPOLIS. WINDS GUSTS IN THE VICINITY
OF THE LINE HAVE BEEN QUITE VARIABLE THE PAST FEW HOURS / FROM 35-45
KTS / AND GENERALLY SUB-SEVERE. THIS TREND IS EXPECTED TO CONTINUE
FOR MOST OF THE LINE SEGMENT...EXCEPT FOR AREAS OF CNTRL/WCNTRL WV
WHERE BETTER INSTABILITY / 1500-200 J/KG OF 100 MB MIXED CAPE VALUES
/ EXIST. RECENT RLX VAD PROFILES INDICATES AROUND 10 KTS OF WSWLY
BOUNDARY LAYER FLOW AHEAD OF THE LINE...HENCE STORM RELATIVE INFLOW
INTO REMAINING SEGMENT IS RATHER WEAK. HOWEVER...MODERATE AMOUNTS
OF INSTABILITY SHOULD OVERCOME THIS LIMITATION IN PARTS OF
WCNTRL/CNTRL WV SWD INTO AREAS JUST SOUTH OF WW 668.  

AREAS FURTHER NORTH...IN PORTIONS OF NRN WV INTO ECNTRL/SCNTRL PA
WILL LIKELY EXPERIENCE A SUB-SEVERE WIND THREAT AS MIXED CAPE VALUES
ARE MUCH LESS / 500-1000 J/KG / BENEATH 20-25 KTS AT 500MB.

..NADEN.. 07/07/2003

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

ATTN...WFO...CTP...RNK...PBZ...RLX...CLE...ILN...

38868249 41788122 41627804 38138055

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 6, 9:46 PM EDTMesoscale DiscussionSPCAllen, Auglaize, Champaign, Crawford, Darke, Defiance and 21 more59 min
Jul 7, 12:10 AM EDTSevere Thunderstorm WatchSPCButler, Clermont, Darke, Hamilton, Miami, Montgomery and 3 more3 hr
Jul 7, 12:51 AM EDTMesoscale DiscussionSPCButler, Clermont, Darke, Hamilton, Miami, Montgomery and 2 more114 min
Jul 7, 9:30 AM EDTMesoscale DiscussionSPCAllen, Auglaize, Darke, Defiance, Fulton, Hancock and 12 more60 min
Jul 7, 9:45 AM EDTSevere Thunderstorm WatchSPCDefiance, Fulton, Paulding, Williams4 hr
Jul 7, 11:14 AM EDTMesoscale DiscussionSPCAllen, Ashland, Auglaize, Butler, Champaign, Clark and 37 more61 min
Jul 7, 12:30 PM EDTSevere Thunderstorm WatchSPCAllen, Ashland, Auglaize, Champaign, Clark, Coshocton and 43 more6 hr
Jul 7, 1:14 PM EDTMesoscale DiscussionSPCAllen, Auglaize, Defiance, Fulton, Henry, Lucas and 6 more61 min
Jul 7, 2:56 PM EDTMesoscale DiscussionSPCAshland, Belmont, Carroll, Champaign, Clark, Columbiana and 42 more94 min
Jul 7, 3:10 PM EDTSevere Thunderstorm WatchSPCAthens, Belmont, Carroll, Columbiana, Guernsey, Harrison and 12 more6 hr
Jul 7, 6:30 PM EDTTornado WatchSPCAllen, Auglaize, Champaign, Clark, Darke, Defiance and 13 more6 hr
Jul 7, 12:10 PM EDTMesoscale DiscussionSPCBerks, Bucks, Carbon, Columbia, Lackawanna, Lebanon and 10 more65 min
Jul 7, 2:23 PM EDTMesoscale DiscussionSPCBerks, Bucks, Carbon, Chester, Delaware, Lackawanna and 12 more67 min
Jul 7, 2:55 PM EDTSevere Thunderstorm WatchSPCBerks, Bucks, Carbon, Chester, Delaware, Lancaster and 8 more5 hr
Jul 7, 6:29 PM EDTMesoscale DiscussionSPCBerks, Bucks, Carbon, Chester, Delaware, Lancaster and 7 more61 min

Nearby

Mesoscale Discussions in West Virginia, 2003Mesoscale Discussions in Ohio, 2003Mesoscale Discussions in Pennsylvania, 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.