Alert archive / Wyoming / Flash Flood Watches in 2018

Flash Flood Watch 8, NWS Cheyenne, WY

July 25, 2018Albany County, Carbon County, Laramie County, Wyoming; Kimball County, Nebraska

NWS Cheyenne, WY issued this flash flood watch at Jul 25, 2018, 10:11 AM MDT for Albany County, Carbon County, Laramie County, Wyoming; Kimball County, Nebraska. It took effect at Jul 25, 2018, 4:00 PM MDT. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Jul 25, 2018, 10:11 AM MDT (16:11 UTC)
In effect from
Jul 25, 2018, 4:00 PM MDT
Expired
Jul 25, 2018, 9:29 PM MDT
In force
5 hr
Issued by
NWS Cheyenne, WY
Flood severity
None

Counties Kimball County, NE, Albany County, WY, Carbon County, WY, Laramie County, WY

The radar

The Cheyenne radar (KCYS), 52 km from the middle of the area, began a volume at 16:10 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

Denver, CO (KDEN), launched 12:00Z, 4.2 hours before the alert went out and 247 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, Denver, CO at 12:00Z on 2018-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 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, Denver, CO at 12:00Z on 2018-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 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
20 J/kg
Mixed-layer CIN
-431 J/kg
Mixed-layer LCL
2245 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
74 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Cheyenne, WY wrote its last area forecast discussion before this flash flood watch went out at Jul 25, 9:15 AM MDT, 56 minutes earlier.

Area forecast discussion, Jul 25, 9:15 AM MDT, 56 minutes before
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Hazardous weather outlook, Jul 25, 4:01 AM MDT, 6 hours 10 minutes before
Hazardous Weather Outlook
National Weather Service Cheyenne WY
401 AM MDT Wed Jul 25 2018

NEZ002-003-019>021-054-055-095-096-WYZ101>103-106>108-116>119-
261030-
Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne-
North Sioux-South Sioux-Converse County Lower Elevations-
Niobrara County-North Laramie Range-
Central Laramie Range and Southwest Platte County-
East Platte County-Goshen County-South Laramie Range-
South Laramie Range Foothills-Central Laramie County-
East Laramie County-
401 AM MDT Wed Jul 25 2018

This hazardous weather outlook is for portions of western
Nebraska...east central Wyoming and southeast Wyoming.

.DAY ONE...TODAY AND TONIGHT

Scattered thunderstorms will develop over the area this afternoon
and continue through this evening. A few strong storms are
possible with gusty winds and hail the main threats.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

Scattered to numerous showers and thunderstorms are expected
Thursday through Sunday. Heavy rain is possible along with some
potential for strong storms Thursday and Friday.

.Spotter information statement...

Spotter activation is not expected at this time.

WYZ104-105-109>115-261030-
Ferris/Seminoe/Shirley Mountains-Shirley Basin-
Central Carbon County-North Snowy Range Foothills-
Southwest Carbon County-Sierra Madre Range-
Upper North Platte River Basin-Snowy Range-Laramie Valley-
401 AM MDT Wed Jul 25 2018

This hazardous weather outlook is for portions of south central
Wyoming and southeast Wyoming.

.DAY ONE...TODAY AND TONIGHT

Scattered thunderstorms will develop over the area this afternoon
and continue through early this evening. Severe storms are not
anticipated.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

Scattered showers and thunderstorms are expected Thursday through
Sunday. Heavy rain is possible with stronger storms.

.Spotter information statement...

Spotter activation will not be needed.

In the hours before

Special weather statement, Jul 25, 4:52 AM MDT, 5 hours 19 minutes before
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The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 24, 10:08 PM MDTSpecial Weather StatementCYSNiobrara37 min
Jul 25, 1:07 PM MDTSpecial Weather StatementCYSAlbany38 min
Jul 25, 2:01 PM MDTSpecial Weather StatementCYSAlbany44 min
Jul 25, 2:46 PM MDTSpecial Weather StatementCYSAlbany44 min
Jul 25, 3:10 PM MDTSevere Thunderstorm WarningCYSAlbany, Laramie50 min
Jul 25, 3:17 PM MDTSevere Thunderstorm WarningCYSLaramie43 min
Jul 25, 3:44 PM MDTSevere Thunderstorm WarningCYSLaramie46 min
Jul 25, 4:12 PM MDTFlash Flood WarningCYSLaramie117 min
Jul 25, 4:24 PM MDTSevere Thunderstorm WarningCYSLaramie38 min
Jul 24, 6:08 PM MDTSpecial Weather StatementCYSScotts Bluff52 min
Jul 24, 6:17 PM MDTSevere Thunderstorm WarningCYSMorrill, Scotts Bluff43 min
Jul 24, 6:51 PM MDTSpecial Weather StatementCYSDawes39 min
Jul 24, 7:35 PM MDTSpecial Weather StatementCYSBox Butte40 min
Jul 24, 11:34 PM MDTSpecial Weather StatementCYSDawes41 min
Jul 25, 12:12 AM MDTSpecial Weather StatementCYSDawes48 min
Jul 25, 2:53 AM MDTSpecial Weather StatementCYSDawes52 min
Jul 25, 3:44 AM MDTSpecial Weather StatementCYSBox Butte46 min
Jul 25, 4:52 AM MDTSpecial Weather StatementCYSDawes53 min

Nearby

Flash Flood Watches in Wyoming, 2018Flash Flood Watches in Nebraska, 2018Every flash flood watch in 2018

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.