Alert archive / Oklahoma / Mesoscale Discussions in 2004

Mesoscale Discussion 403

April 20, 20044 counties in Arkansas; 12 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2004, 10:39 PM CDT for 4 counties in Arkansas; 12 counties in Oklahoma. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Apr 20, 2004, 10:39 PM CDT (03:39 UTC)
Expired: Apr 21, 2004, 1:45 AM CDT
In force: 3 hr
Issued by: the Storm Prediction Center

Counties Crawford County, AR, Franklin County, AR, Scott County, AR, Sebastian County, AR, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Pittsburg County, OK, Pottawatomie County, OK, Seminole County, OK, Sequoyah County, OK

The radar

The Western Arkansas radar (KSRX), 91 km from the middle of the area, began a volume at 03:39 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

Norman, OK (KOUN), launched 00:00Z, 3.7 hours before the alert went out and 187 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 3300 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 150 m²/s²
0-3 km storm-relative helicity: 144 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.

606 
ACUS11 KWNS 210340
SWOMCD
SPC MCD 210339 
ARZ000-OKZ000-210645-

MESOSCALE DISCUSSION 0403
NWS STORM PREDICTION CENTER NORMAN OK
1039 PM CDT TUE APR 20 2004

AREAS AFFECTED...ECENTRAL/SERN OK AND WRN AR

CONCERNING...HEAVY RAINFALL 

VALID 210339Z - 210645Z

TRAINING/BACKBUILDING OF STRONG-SEVERE THUNDERSTORMS IS EXPECTED
OVER ECENTRAL/SERN OK INTO WRN AR THROUGH THE NEXT 3-6 HOURS. HOURLY
RAINFALL ACCUMULATIONS FROM 1-2 INCHES WILL BE POSSIBLE.
ADDITIONALLY A SEVERE THREAT WILL REMAIN OVER MUCH OF THIS AREA
WITHIN WW 97. PLEASE SEE SWOMCD 404 FOR THESE DETAILS.

LATEST REGIONAL PROFILER DATA AND SFC OBSERVATIONS CONFIRM THAT THE
LOW LEVEL JET HAS BEGUN TO VEER AS THE UPPER TROUGH OVER THE MIDWEST
CONTINUES TO EJECT EWD. AN OUTFLOW BOUNDARY EXTENDING FROM A LOW
PRESSURE AREA JUST SOUTH OF OKLAHOMA CITY EWD TO NEAR MUSKOGEE
ASSOCIATED WITH CONVECTION OVER ECENTRAL OK. WITH VERY LITTLE IN THE
WAY OF PRESSURE RISES BEHIND THIS BOUNDARY...IT SHOULD REMAIN NEARLY
STATIONARY OVER THE NEXT FEW HOURS. THIS BOUNDARY WILL CONTINUE TO
AID AS A FOCUS FOR REDEVELOPMENT FROM SHAWNEE/SEMINOLE AREAS EWD
INTO FAR WRN AR /FSM AREA/. ALTHOUGH A SLOW SWD DRIFT OF THE
BOUNDARY AND CONVECTIVE LINE IS ANTICIPATED...A CONTINUED VEERING OF
THE LOW LEVEL JET  WILL SET UP A FAVORABLE SITUATION FOR
BACKBUILDING OF THE CONVECTIVE LINE OVER ECENTRAL AND EVENTUALLY
SERN OK OVERNIGHT. ADDITIONALLY...THE NEARLY PARALLEL ORIENTATION OF
THE CONVECTIVE OUTFLOW BOUNDARY TO THE DEEP LAYER SHEAR VECTOR WILL
SUPPORT TRAINING ECHOES THAT WILL ENHANCE THE THREAT FOR HEAVY
RAINFALL INTO FAR ECENTRAL OK AND WCENTRAL AR.

..CROSBIE.. 04/21/2004

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

ATTN...WFO...LZK...SHV...TSA...OUN...

34479447 34829628 35149705 35479698 35639646 35729492
35629377 34629369

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 20, 7:22 PM CDT	Mesoscale Discussion	SPC	Benton, Madison, Washington	23 min
Apr 20, 7:50 PM CDT	Tornado Watch	SPC	Benton, Carroll, Crawford, Madison, Washington	5 hr
Apr 20, 8:57 PM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Crawford, Madison, Washington	2 hr
Apr 20, 10:57 PM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Crawford, Madison, Washington	93 min
Apr 21, 2:13 PM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Clark, Cleburne, Cleveland, Conway and 30 more	92 min
Apr 21, 2:40 PM CDT	Tornado Watch	SPC	Arkansas, Ashley, Baxter, Benton, Boone, Bradley and 52 more	6 hr
Apr 21, 4:40 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Baxter, Benton, Boone, Bradley and 52 more	95 min
Apr 21, 6:29 PM CDT	Mesoscale Discussion	SPC	Arkansas, Baxter, Benton, Boone, Carroll, Chicot and 25 more	91 min
Apr 21, 12:58 PM CDT	Mesoscale Discussion	SPC	Atoka, Beckham, Blaine, Bryan, Caddo, Canadian and 34 more	2 hr
Apr 21, 1:50 PM CDT	Tornado Watch	SPC	Adair, Alfalfa, Atoka, Beckham, Blaine, Caddo and 55 more	7 hr
Apr 21, 1:56 PM CDT	Mesoscale Discussion	SPC	Beaver, Cimarron, Texas	94 min
Apr 21, 3:00 PM CDT	Severe Thunderstorm Watch	SPC	Beaver, Cimarron, Texas	6 hr
Apr 21, 4:39 PM CDT	Mesoscale Discussion	SPC	Adair, Alfalfa, Atoka, Beckham, Blaine, Caddo and 47 more	66 min
Apr 21, 5:09 PM CDT	Mesoscale Discussion	SPC	Beaver, Cimarron, Texas	66 min
Apr 21, 6:02 PM CDT	Mesoscale Discussion	SPC	Adair, Alfalfa, Atoka, Blaine, Canadian, Cherokee and 43 more	88 min

Nearby

Mesoscale Discussions in Oklahoma, 2004 Mesoscale Discussions in Arkansas, 2004 Every mesoscale discussion in 2004

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.