Alert archive / Colorado / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 202, NWS Goodland, KS

August 21, 2007Cheyenne County, Colorado

NWS Goodland, KS issued this severe thunderstorm warning at Aug 21, 2007, 6:51 PM MDT for Cheyenne County, Colorado. It was in force for 28 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 21, 2007, 6:51 PM MDT (00:51 UTC)
Expired
Aug 21, 2007, 7:19 PM MDT
In force
28 min
Issued by
NWS Goodland, KS
Area
Counties, with a storm outline in the text

County Cheyenne County, CO

The radar

The Goodland radar (KGLD), 98 km from the middle of the area, began a volume at 00:52 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 21, 2:50 PM MDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Dodge City, (KDDC), launched 00:00Z, 0.9 hours before the alert went out and 264 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, Dodge City, at 00:00Z on 2007-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2716 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, Dodge City, at 00:00Z on 2007-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 66 square meters per square second.1939Sfc1 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
2716 J/kg
Mixed-layer CIN
-103 J/kg
Mixed-layer LCL
1778 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
177 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Goodland, KS wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 21, 6:05 PM MDT, 46 minutes earlier.

Area forecast discussion, Aug 21, 6:05 PM MDT, 46 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
605 PM MDT TUE AUG 21 2007

.AVIATION...
FOR THE 00Z TAF ISSUANCE...SCATTERED TSRA THAT DEVELOPED ALONG A
SFC TROUGH AXIS CONTINUES ACROSS PORTIONS OF NORTHWEST KANSAS AND
EAST CENTRAL COLORADO. STORM MOTION WAS TO THE EAST AND SINCE THIS
CONVECTION IS NOT LIKELY TO ORGANIZE INTO A SQUALL LINE...LEFT
VCTS IN BOTH KGLD AND KMCK THROUGH ABOUT 04Z. OTHERWISE CONDITIONS
WILL REMAIN VFR THROUGH THE 24 HOUR FORECAST PERIOD WITH SOUTHERLY
WINDS. INSERTED VCTS WED AFTERNOON AS CONVERGENCE ALONG A TROUGH
AXIS IS LIKELY TO GENERATE SCATTERED TSRA TO THE FCST AREA.

CLK

&&

.PREV DISCUSSION... /ISSUED 243 PM MDT TUE AUG 21 2007/

.DISCUSSION...THE 20Z SURFACE ANALYSIS PLACES A TROUGH ACROSS
NORTHWEST KANSAS. THE LATEST VISIBLE SATELLITE SHOWING CU DEVELOPING
ALONG THE TROUGH AXIS. WATER VAPOR INDICATES THE SHORTWAVE TROUGH IS
MOVING EAST INTO THE DAKOTAS.

UPPER FLOW THROUGH THURSDAY WILL BE ZONAL. A TROUGH WILL MOVE
THROUGH THE FLOW ON FRIDAY. A SURFACE TROUGH IS EXPECTED TO PERSIST
ACROSS THE FORECAST AREA THROUGH THURSDAY NIGHT AND THEN FOLLOWED BY
HIGH PRESSURE ON FRIDAY.

THE MAIN FORECAST ISSUE IS POPS.

A PERSISTENT TROUGH WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT
EACH AFTERNOON/EVENING THROUGH FRIDAY NIGHT. UPWARD VERTICAL
VELOCITIES INDICATE FORCING WILL BE AVAILABLE NEAR THE TROUGH EACH
AFTERNOON/NIGHT. A STEADY STREAM OF SHORTWAVE ENERGY WILL HELP FIRE
STORMS ALONG THE TROUGH AXIS. POPS SHOULD BE THE HIGHEST THROUGH
THURSDAY NIGHT WITH DECREASING POPS ON FRIDAY WHEN MODELS ARE IN
AGREEMENT THAT THE FRONT SHOULD BE EXITING THE SOUTHERN ZONES.  SOME
UPSLOPE THURSDAY NIGHT WILL FURTHER ENHANCE LIFT FOR WIDESPREAD
PRECIPITATION. PLAN TO GO WITH CHANCE POPS FOR EACH PERIOD AND THEN
SLIGHT CHANCE POPS ON FRIDAY.

850MB TEMPERATURES INDICATE A TREND TOWARD COOLER TEMPERATURES ON
FRIDAY. OTHERWISE MORE CLOUDS AND PRECIPITATION THAN IN RECENT DAYS
SHOULD ALSO HELP REDUCE MAX TEMPERATURES TO THE LOWER 90S ON
WEDNESDAY AND INTO THE UPPER 80S ON THURSDAY. LOWER TO MID 80S WILL
BE A WELCOME CHANGE ON FRIDAY. MIN TEMPERATURES WILL START IN THE
LOWER 60S WEST TO THE UPPER 60S EAST COOLING SLIGHTLY INTO THE UPPER
50S WEST TO THE MID 60S EAST BY THURSDAY NIGHT/FRIDAY NIGHT.

IN THE EXTENDED...A RIDGE WILL BE OVER THE PLAINS THROUGH SUNDAY AND
THEN SHIFT EAST ON MONDAY IN RESPONSE TO A LOW MOVING EAST ACROSS
CANADA. A SURFACE HIGH WILL BE PRESENT ON SATURDAY AND IS THEN
REPLACED BY LOW PRESSURE FOR THE PERIOD SUNDAY THROUGH TUESDAY.
SUBSIDENCE AND LACK OF DYNAMICS WILL KEEP POPS NIL THROUGH MONDAY. A
SHORTWAVE WILL MOVE ACROSS THE FORECAST AREA ON TUESDAY SO FOR NOW
WILL HANDLE THAT WITH SLIGHT CHANCE POPS. MAX TEMPERATURES WILL WARM
FROM THE MID 80S TO THE MID/UPPER 80S WITH SOME LOWER 90S IN THE
EAST. MIN TEMPERATURES SHOULD RANGE FROM THE UPPER 50S WEST TO THE
MID 60S EAST.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&

FS
Hazardous weather outlook, Aug 21, 10:40 AM MDT, 8 hours 11 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GOODLAND KS
1040 AM MDT TUE AUG 21 2007

COZ090>092-KSZ001>004-013>016-027>029-041-042-NEZ079>081-221200-
YUMA-KIT CARSON-CHEYENNE CO-CHEYENNE KS-RAWLINS-DECATUR-NORTON-
SHERMAN-THOMAS-SHERIDAN-GRAHAM-WALLACE-LOGAN-GOVE-GREELEY-WICHITA-
DUNDY-HITCHCOCK-RED WILLOW-
1040 AM MDT TUE AUG 21 2007 /1140 AM CDT TUE AUG 21 2007/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EXTREME SOUTHWEST
NEBRASKA...NORTHWEST KANSAS AND EAST CENTRAL COLORADO.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND TONIGHT FOR MUCH
OF THE REGION. STORMS ARE EXPECTED TO FORM ALONG A TROUGH NEAR THE
COLORADO STATE LINE AND MOVE TO THE NORTHEAST AT 20 MPH. SOME OF
THESE STORMS MAY BE SEVERE WITH DAMAGING WINDS BEING THE MAIN
THREAT. IN ADDITION SOME LARGE HAIL AND LOCALLY HEAVY RAIN IS
POSSIBLE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A COLD FRONT SLIDES INTO THE REGION TOMORROW BRINGING A CHANCE OF
THUNDERSTORMS FROM TOMORROW AFTERNOON THROUGH FRIDAY. SOME OF THE
STORMS TOMORROW AND THURSDAY MAY BE SEVERE WITH DAMAGING WINDS
AND LARGE HAIL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING ESPECIALLY
ALONG AND EAST OF THE COLORADO STATE LINE.

JOHNSON/BULLER

In the hours before

Local storm report, Aug 21, 5:14 PM MDT, 1 hour 37 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
514 PM MDT TUE AUG 21 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0513 PM     HAIL             3 W ATWOOD              39.81N 101.10W
08/21/2007  M1.00 INCH       RAWLINS            KS   TRAINED SPOTTER

&&

BOYD
Local storm report, Aug 21, 5:23 PM MDT, 1 hour 28 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
523 PM MDT TUE AUG 21 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0455 PM     HAIL             8 SE ATWOOD             39.73N 100.93W
08/21/2007  M2.50 INCH       RAWLINS            KS   TRAINED SPOTTER

            2 INCHES OF RAIN

&&

BOYD
Local storm report, Aug 21, 6:17 PM MDT, 34 minutes before
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Special weather statement, Aug 21, 6:25 PM MDT, 26 minutes before
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Local storm report, Aug 21, 6:31 PM MDT, 20 minutes before
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Special weather statement, Aug 21, 6:33 PM MDT, 18 minutes before
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The office that day

Everything else NWS Goodland, KS issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 21, 6:53 PM MDTSevere Thunderstorm WarningGLDLogan, Wallace67 min
Aug 21, 9:10 PM MDTSevere Thunderstorm WarningGLDSherman65 min
Aug 22, 3:36 PM MDTSevere Thunderstorm WarningGLDLogan, Wallace54 min
Aug 22, 4:04 PM MDTFlash Flood WarningGLDLogan, Wallace3 hr
Aug 22, 4:27 PM MDTSevere Thunderstorm WarningGLDLogan, Wallace63 min
Aug 22, 5:04 PM MDTSevere Thunderstorm WarningGLDGraham, Norton45 min
Aug 21, 8:46 PM MDTSevere Thunderstorm WarningGLDRed Willow34 min
Aug 22, 3:09 PM MDTSevere Thunderstorm WarningGLDHitchcock51 min
Aug 22, 3:51 PM MDTSevere Thunderstorm WarningGLDRed Willow54 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2007Every severe thunderstorm warning in 2007

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.