Alert archive / North Dakota / Mesoscale Discussions in 2005
Mesoscale Discussion 1821
The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2005, 8:16 PM MDT for 14 counties in North Dakota; 13 counties in South Dakota. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- Jul 21, 2005, 8:16 PM MDT (02:16 UTC)
- Expired
- Jul 21, 2005, 9:45 PM MDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
All 27 counties
Adams County, ND, Burleigh County, ND, Emmons County, ND, Grant County, ND, Hettinger County, ND, Kidder County, ND, McLean County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Sheridan County, ND, Sioux County, ND, Stark County, ND, Wells County, ND, Campbell County, SD, Corson County, SD, Dewey County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Meade County, SD, Mellette County, SD, Pennington County, SD, Perkins County, SD, Stanley County, SD, Walworth County, SD, Ziebach County, SD
The radar
The Bismarck radar (KBIS), 141 km from the middle of the area, began a volume at 02:17 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
Bismarck Municip, ND (KBIS), launched 00:00Z, 2.3 hours before the alert went out and 143 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
- 1122 J/kg
- Mixed-layer CIN
- -57 J/kg
- Mixed-layer LCL
- 1835 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 90 m²/s²
- 0-3 km storm-relative helicity
- 198 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 5.1
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 220216 SWOMCD SPC MCD 220216 NDZ000-SDZ000-220345- MESOSCALE DISCUSSION 1821 NWS STORM PREDICTION CENTER NORMAN OK 0916 PM CDT THU JUL 21 2005 AREAS AFFECTED...PORTIONS WRN/CNTRL ND INTO WRN SD CONCERNING...SEVERE THUNDERSTORM WATCH 657...658... VALID 220216Z - 220345Z THROUGH 04Z...GREATEST THREAT OF LARGE HAIL AND DAMAGING WINDS WILL EXIST ACROSS CNTRL AND POSSIBLY SRN PORTIONS OF WW 658. AS OF 0205Z...RAP RADAR IMAGERY SHOWED AN INTENSE TSTM CLUSTER WITH AT LEAST ONE EMBEDDED SUPERCELL OVER SERN MEADE...NERN PENNINGTON...SRN ZIEBACH AND NRN HAAKON COUNTIES MOVING 330/30-35 KTS. IT APPEARS THAT ASSOCIATED GUST FRONT HAS STARTED TO SURGE AHEAD OF PARENT STORMS...AT LEAST ALONG WRN PORTION OF COMPLEX. INFLOW AIR MASS REMAINS WARM AND MOIST...SUGGESTING THAT CAP LIKELY HAS NOT STRENGTHENED TOO SIGNIFICANTLY. THEREFORE...IT APPEARS THAT PRIMARY FAILURE MODE OF SYSTEM WOULD BE IF GUST FRONT CONTINUES TO OUTRUN STORM CLUSTER. GIVEN THE EMBEDDED SUPERCELL STRUCTURES...HAIL TO GOLFBALL SIZE OR LARGER IN ADDITION TO DAMAGING WINDS WILL REMAIN POSSIBLE WITH COMPLEX AS IT MOVES ACROSS I-90. FARTHER TO THE N...SEVERAL LEFT-MOVING SUPERCELLS HAVE BEEN OBSERVED THIS EVENING ALONG OUTFLOW BOUNDARIES ORIGINATING FROM EARLIER CONVECTION. CURRENTLY...THE MOST INTENSE STORM IS LEFT-MOVING SUPERCELL OVER SRN SHERIDAN COUNTY ND WHICH IS CAPABLE OF LARGE HAIL. AIR MASS ACROSS ND PORTION OF WW 657 HAS COOLED INTO THE 70S...LARGELY AS A RESULT OF CONVECTIVE OUTFLOW. ISOLATED LARGE HAIL WILL REMAIN POSSIBLE WITH MOST INTENSE STORMS LIKELY SLIGHTLY ELEVATED ABOVE STABILIZING BOUNDARY-LAYER. OVERALL SEVERE WEATHER THREAT IS EXPECTED TO SLOWLY DIMINISH THROUGH 04Z. ..MEAD.. 07/22/2005 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FGF...ABR...BIS...UNR... 47660237 47659917 45100009 45140045 43570048 43610294 45150295 45160325
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 6:23 PM MDT | Mesoscale Discussion | SPC | Haakon, Jones, Meade, Pennington, Stanley, Ziebach | 67 min |
| Jul 21, 6:30 PM MDT | Severe Thunderstorm Watch | SPC | Dewey, Haakon, Jackson, Jones, Meade, Pennington and 2 more | 5 hr |
| Jul 21, 10:25 PM MDT | Mesoscale Discussion | SPC | Bennett, Jackson, Oglala Lakota | 65 min |
Nearby
Mesoscale Discussions in North Dakota, 2005Mesoscale Discussions in South Dakota, 2005Every mesoscale discussion in 2005
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.