Alert archive / Oklahoma / Mesoscale Discussions in 2004

Mesoscale Discussion 424

April 21, 200413 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2004, 10:26 PM CDT for 13 counties in Oklahoma. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Apr 21, 2004, 10:26 PM CDT (03:26 UTC)
Expired
Apr 21, 2004, 11:30 PM CDT
In force
64 min
Issued by
the Storm Prediction Center

Counties Atoka County, OK, Bryan County, OK, Choctaw County, OK, Coal County, OK, Haskell County, OK, Hughes County, OK, Johnston County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, Pittsburg County, OK, Pushmataha County, OK, Seminole County, OK

The radar

The Western Arkansas radar (KSRX), 158 km from the middle of the area, began a volume at 03:26 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 00:00Z, 3.4 hours before the alert went out and 168 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, Norman, OK at 00:00Z on 2004-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 415 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, Norman, OK at 00:00Z on 2004-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.19395878Sfc1 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
415 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
1340 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
357 m²/s²
Significant tornado parameter
0.4
Supercell composite
11.0

Open this sounding in Storm Lab

The text

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

098 
ACUS11 KWNS 220326
SWOMCD
SPC MCD 220326 
OKZ000-TXZ000-220430-

MESOSCALE DISCUSSION 0424
NWS STORM PREDICTION CENTER NORMAN OK
1026 PM CDT WED APR 21 2004

AREAS AFFECTED...SERN OK

CONCERNING...TORNADO WATCH 101...

VALID 220326Z - 220430Z

TORNADO THREAT CONTINUES WITHIN WW...THOUGH 3/4-2 INCH DIAMETER HAIL
APPEARS TO BE THE MAIN THREAT. MOST STORMS ARE IN NRN PORTION OF WW
AND THE WATCH MAY BE CANCELLED EARLY IF THESE STORMS SHIFT NWD OUT
OF THE AREA. 

THE AIR MASS ACROSS SERN OK REMAINS MODERATELY UNSTABLE AND DEEP
LAYER SHEAR AROUND 55 KT. THE NUMBER OF STORMS HAS DECREASED DURING
THE PAST HOUR...BUT THE STORMS THAT REMAIN ARE SEVERE WITH HAIL
LIKELY. LOCAL VAD WIND PROFILES SHOW STRONG TURNING...SUPPORTIVE OF
TORNADOES...THOUGH THERE MAY BE SUFFICIENT DECOUPLING OF THE
BOUNDARY LAYER THAT MIGHT INHIBIT TORNADOGENESIS.

..IMY.. 04/22/2004

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

ATTN...WFO...SHV...TSA...FWD...OUN...

33919669 35369660 35289446 33969453

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 7:06 PM CDTMesoscale DiscussionSPCAlfalfa, Beaver, Blaine, Dewey, Ellis, Harper and 3 more2 hr
Apr 21, 7:51 PM CDTMesoscale DiscussionSPCAlfalfa, Blaine, Choctaw, Cleveland, Creek, Delaware and 18 more84 min
Apr 21, 8:35 PM CDTSevere Thunderstorm WatchSPCAlfalfa, Blaine, Dewey, Ellis, Garfield, Grant and 9 more5 hr
Apr 21, 8:35 PM CDTTornado WatchSPCAtoka, Bryan, Choctaw, Coal, Haskell, Hughes and 6 more5 hr
Apr 21, 10:10 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Craig, Creek, Delaware, Mayes and 8 more95 min
Apr 21, 10:50 PM CDTSevere Thunderstorm WatchSPCAdair, Cherokee, Craig, Creek, Delaware, Haskell and 14 more5 hr
Apr 21, 10:56 PM CDTMesoscale DiscussionSPCAlfalfa, Garfield, Grant, Kay, Kingfisher, Logan and 2 more94 min
Apr 22, 1:43 AM CDTMesoscale DiscussionSPCAdair, Cherokee, Haskell, McIntosh, Mayes, Muskogee and 7 more92 min
Apr 22, 12:32 PM CDTMesoscale DiscussionSPCAdair, Atoka, Cherokee, Coal, Delaware, Haskell and 15 more88 min
Apr 22, 1:40 PM CDTTornado WatchSPCAdair, Atoka, Bryan, Carter, Cherokee, Choctaw and 33 more6 hr
Apr 22, 3:26 PM CDTMesoscale DiscussionSPCAdair, Atoka, Cherokee, Coal, Haskell, Hughes and 16 more64 min
Apr 22, 4:30 PM CDTTornado WatchSPCBryan, Love6 hr
Apr 22, 5:27 PM CDTMesoscale DiscussionSPCAdair, Atoka, Bryan, Choctaw, Coal, Craig and 23 more63 min
Apr 22, 6:23 PM CDTMesoscale DiscussionSPCAdair, Carter, Garvin, Hughes, LeFlore, McCurtain and 10 more67 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.