Alert archive / Wyoming / Mesoscale Discussions in 2003

Mesoscale Discussion 2176

August 17, 20036 counties in Nebraska; Custer County, Fall River County, Lawrence County, South Dakota; 13 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2003, 4:42 PM MDT for 6 counties in Nebraska; Custer County, Fall River County, Lawrence County, South Dakota; 13 counties in Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 17, 2003, 4:42 PM MDT (22:42 UTC)
Expired
Aug 17, 2003, 6:45 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center
All 22 counties

Banner County, NE, Box Butte County, NE, Dawes County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Custer County, SD, Fall River County, SD, Lawrence County, SD, Big Horn County, WY, Campbell County, WY, Converse County, WY, Crook County, WY, Goshen County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Niobrara County, WY, Platte County, WY, Sheridan County, WY, Washakie County, WY, Weston County, WY

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 10.7 hours before the alert went out and 220 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, Rapid City, SD at 12:00Z on 2003-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Rapid City, SD at 12:00Z on 2003-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3070 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
37 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.

975 
ACUS11 KWNS 172243
SWOMCD
SPC MCD 172242 
NEZ000-SDZ000-WYZ000-180045-

MESOSCALE DISCUSSION 2176
NWS STORM PREDICTION CENTER NORMAN OK
0542 PM CDT SUN AUG 17 2003

AREAS AFFECTED...MUCH OF NRN AND ERN WY...BLACK HILLS...WRN NEBRASKA
PANHANDLE

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 172242Z - 180045Z

ISOLATED SEVERE HAIL WILL BE POSSIBLE THROUGH THE EARLY EVENING
HOURS. NO WW IS EXPECTED.

SURFACE ANALYSIS SHOWS STRONG CONVERGENCE OVER ERN WY AS UPPER LOW
APPROACHES.  THIS WILL ALLOW FOR A CONTINUATION OF THE FORMATION OF
SCATTERED THUNDERSTORMS.  ALTHOUGH OVERALL WIND SHEAR PROFILES ARE
WEAK...STRONG FORCING...BOUNDARY LAYER MIXING RATIOS ON THE ORDER OF
10 G/KG ALONG WITH STEEP LAPSE RATES ALOFT WITH UPPER LOW WILL
CONTINUE THE THREAT OF SEVERE HAIL WITH THE STRONGEST STORMS UNTIL
AIR MASS BEGINS TO STABILIZE LATER THIS EVENING.

..JEWELL.. 08/17/2003

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

ATTN...WFO...LBF...UNR...CYS...BYZ...RIW...

44730832 44890386 44520337 43660342 41220233 41430451
42200609 43120879

Nearby

Mesoscale Discussions in Wyoming, 2003Mesoscale Discussions in Nebraska, 2003Mesoscale Discussions in South Dakota, 2003Every mesoscale discussion in 2003

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.