Alert archive / Oklahoma / Mesoscale Discussions in 2004
Mesoscale Discussion 413
The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2004, 4:39 PM CDT for 53 counties in Oklahoma. It was in force for 66 min.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2004, 4:39 PM CDT (21:39 UTC)
- Expired
- Apr 21, 2004, 5:45 PM CDT
- In force
- 66 min
- Issued by
- the Storm Prediction Center
All 53 counties
Adair County, OK, Alfalfa County, OK, Atoka County, OK, Beckham County, OK, Blaine County, OK, Caddo County, OK, Cherokee County, OK, Coal County, OK, Comanche County, OK, Creek County, OK, Custer County, OK, Delaware County, OK, Dewey County, OK, Ellis County, OK, Garfield County, OK, Grant County, OK, Greer County, OK, Harper County, OK, Haskell County, OK, Hughes County, OK, Jackson County, OK, Kingfisher County, OK, Kiowa County, OK, Latimer County, OK, LeFlore County, OK, Lincoln County, OK, Logan County, OK, Major County, OK, Mayes County, OK, McCurtain County, OK, McIntosh County, OK, Murray County, OK, Muskogee County, OK, Noble County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Pittsburg County, OK, Pottawatomie County, OK, Pushmataha County, OK, Roger Mills County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Stephens County, OK, Tulsa County, OK, Wagoner County, OK, Washita County, OK, Woods County, OK, Woodward County, OK
The radar
The Norman radar (KTLX), 13 km from the middle of the area, began a volume at 21:43 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
Norman, OK (KOUN), launched 12:00Z, 9.7 hours before the alert went out and 23 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
- 123 J/kg
- Mixed-layer CIN
- -217 J/kg
- Mixed-layer LCL
- 1714 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- -51 m²/s²
- 0-3 km storm-relative helicity
- 57 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted, in the capitals the NWS used until 2016.
079 ACUS11 KWNS 212139 SWOMCD SPC MCD 212139 ARZ000-OKZ000-KSZ000-TXZ000-212245- MESOSCALE DISCUSSION 0413 NWS STORM PREDICTION CENTER NORMAN OK 0439 PM CDT WED APR 21 2004 AREAS AFFECTED...CENTRAL AND EASTERN OKLAHOMA CONCERNING...TORNADO WATCH 98... VALID 212139Z - 212245Z THREAT FOR BASEBALL SIZED AND LARGER HAIL AND TORNADOES ARE INCREASING ACROSS CENTRAL OKLAHOMA. DRYLINE EXTENDS FROM CADDO COUNTY SWD THROUGH COMANCHE AND COTTON COUNTIES IN WRN OK. AN OLD CONVECTIVE BOUNDARY APPEARS TO EXTEND FROM THE DRYLINE IN CADDO COUNTY EWD INTO OKLAHOMA COUNTY AND EWD TO NEAR FT SMITH. ALTHOUGH THE WINDS ARE ONLY ABOUT 10 KT IN THE BOUNDARY LAYER...STRONGLY VEERING WIND PROFILES...STEEP MID LEVEL LAPSE RATES AND MLCAPES NEAR 2000 J/KG ARE FAVORABLE FOR STORMS TO PRODUCE BASEBALL AND LARGER SIZED HAIL ALONG WITH TORNADOES. THE TORNADO THREAT IS EXPECTED TO INCREASE INTO THE EVENING HOURS AS THE LOW LEVEL JET IS FORECAST TO GRADUALLY STRENGTHEN. VERY LARGE HAIL AND TORNADOES SHOULD ALSO DEVELOP RAPIDLY ALONG I-40 FROM OKLAHOMA CITY EWD TO NEAR FT SMITH WITHIN THE NEXT HOUR. OTHER STORMS ARE DEVELOPING EAST OF THE DRYLINE ACROSS GRADY COUNTY AND THESE STORMS ARE MORE LIKELY TO PRODUCE HAIL UP TO THE SIZE OF BASEBALLS AS THEY INTENSIFY RAPIDLY. ..IMY.. 04/21/2004 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SHV...TSA...OUN...DDC...AMA... 34309700 34579938 34840002 36809996 37079893 36809743 36369457 35289464 33939455 34159611 35849789 35299807 34299776 34869660 35599463
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 | Adair, Cherokee, Craig, Creek, Delaware, Kay and 12 more | 23 min |
| Apr 20, 7:50 PM CDT | Tornado Watch | SPC | Adair, Cherokee, Cleveland, Craig, Creek, Delaware and 13 more | 5 hr |
| Apr 20, 8:57 PM CDT | Mesoscale Discussion | SPC | Adair, Cherokee, Cleveland, Craig, Creek, Delaware and 13 more | 2 hr |
| Apr 20, 10:39 PM CDT | Mesoscale Discussion | SPC | Haskell, Hughes, Latimer, LeFlore, McIntosh, Muskogee and 6 more | 3 hr |
| Apr 20, 10:57 PM CDT | Mesoscale Discussion | SPC | Adair, Cherokee, Cleveland, Craig, Creek, Delaware and 13 more | 93 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, 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, 2004Every 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.