Alert archive / Colorado / Mesoscale Discussions in 2009
Mesoscale Discussion 1521
The Storm Prediction Center issued this mesoscale discussion at Jul 11, 2009, 3:35 PM MDT for 4 states. It was in force for 55 min.
The area
The outline as issued.
The facts
- Issued
- Jul 11, 2009, 3:35 PM MDT (21:35 UTC)
- Expired
- Jul 11, 2009, 4:30 PM MDT
- In force
- 55 min
- Issued by
- the Storm Prediction Center
All 37 counties
Adams County, CO, Arapahoe County, CO, Broomfield County, CO, Cheyenne County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Kit Carson County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Weld County, CO, Yuma County, CO, Cheyenne County, KS, Greeley County, KS, Rawlins County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, Banner County, NE, Box Butte County, NE, Chase County, NE, Cheyenne County, NE, Deuel County, NE, Dundy County, NE, Garden County, NE, Kimball County, NE, Morrill County, NE, Perkins County, NE, Scotts Bluff County, NE, Sioux County, NE, Goshen County, WY, Laramie County, WY, Platte County, WY
The radar
The Denver radar (KFTG), 108 km from the middle of the area, began a volume at 21:36 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
Denver, CO (KDNR), launched 12:00Z, 9.6 hours before the alert went out and 62 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
- 71 J/kg
- Mixed-layer CIN
- -408 J/kg
- Mixed-layer LCL
- 1851 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 21 m²/s²
- 0-3 km storm-relative helicity
- 48 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
000
ACUS11 KWNS 112136
SWOMCD
SPC MCD 112135
KSZ000-NEZ000-COZ000-WYZ000-112230-
MESOSCALE DISCUSSION 1521
NWS STORM PREDICTION CENTER NORMAN OK
0435 PM CDT SAT JUL 11 2009
AREAS AFFECTED...NERN CO...SERN WY...NEB PANHANDLE...NWRN KS
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 112135Z - 112230Z
CONSIDERABLE NUMBER OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
BENEATH UPPER RIDGE OVER THE HIGHER TERRAIN OF CO...LIKELY IN
ASSOCIATION WITH WEAK SHORTWAVE TROUGH THAT IS MASKED WITHIN BROADER
ANTICYCLONIC FLOW ALOFT. ACTIVITY IS NOW SPREADING/DEVELOPING EAST
ALONG THE PALMER DIVIDE SE OF DENVER AND SHOULD BEGIN INGESTING VERY
MOIST/BUOYANT AIRMASS CHARACTERIZED BY MLCAPE ON THE ORDER OF
2000-4000 J/KG. WITH DEEP ELY FLOW ACROSS THE CNTRL HIGH PLAINS IT
SEEMS REASONABLE THAT A CONTINUED UPWARD TREND WILL BE NOTED WITH
THIS ACTIVITY...LIKELY INTO MULTIPLE MCS-TYPE CLUSTERS. INCREASING
CU FIELD ALONG THE LARAMIE RANGE SUGGESTS TSTMS WILL SOON DEVELOP
ACROSS SERN WY AS WELL. WW WILL BE ISSUED SOON TO ACCOUNT FOR THIS
EVOLUTION.
..DARROW.. 07/11/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LBF...GLD...PUB...BOU...CYS...
LAT...LON 38940491 41470534 42770465 42470259 39740086 38280150
38940491SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 11, 12:28 AM MDT | Mesoscale Discussion | SPC | Cheyenne, Kit Carson, Logan, Phillips, Sedgwick, Yuma | 62 min |
| Jul 11, 3:56 PM MDT | Severe Thunderstorm Watch | SPC | Adams, Arapahoe, Cheyenne, Elbert, Kit Carson, Lincoln and 7 more | 9 hr |
| Jul 11, 2:30 AM MDT | Mesoscale Discussion | SPC | Johnson | 90 min |
| Jul 11, 6:14 AM MDT | Mesoscale Discussion | SPC | Keya Paha | 61 min |
| Jul 11, 10:09 AM MDT | Mesoscale Discussion | SPC | Blaine, Brown, Cherry, Custer, Garfield, Greeley and 8 more | 96 min |
Nearby
Mesoscale Discussions in Colorado, 2009Mesoscale Discussions in Nebraska, 2009Mesoscale Discussions in Kansas, 2009Every mesoscale discussion in 2009
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.