Alert archive / Wyoming / Special Weather Statements in 2017
Special Weather Statement, NWS Cheyenne, WY
NWS Cheyenne, WY issued this special weather statement at Aug 5, 2017, 12:29 AM MDT for Goshen County, Wyoming. It was in force for 46 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 5, 2017, 12:29 AM MDT (06:29 UTC)
- Expired
- Aug 5, 2017, 1:15 AM MDT
- In force
- 46 min
- Issued by
- NWS Cheyenne, WY
County Goshen County, WY
The radar
The Cheyenne radar (KCYS), 163 km from the middle of the area, began a volume at 06:31 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
Rapid City, SD (KRAP), launched 00:00Z, 6.5 hours before the alert went out and 210 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
- 410 J/kg
- Mixed-layer CIN
- -38 J/kg
- Mixed-layer LCL
- 2318 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 33 m²/s²
- 0-3 km storm-relative helicity
- 170 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.2
The text
As transmitted.
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</html>What forecasters said that day
The local office's own words before this special weather statement 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 special weather statement went out at Aug 4, 6:16 PM MDT, 6 hours 13 minutes earlier.
Area forecast discussion, Aug 4, 6:16 PM MDT, 6 hours 13 minutes before
Area Forecast Discussion
National Weather Service Cheyenne WY
616 PM MDT Fri Aug 4 2017
.SHORT TERM...(This evening through Sunday)
Issued at 159 PM MDT Fri Aug 4 2017
Skies currently clear across
the region with just a few cumulus clouds popping up in the deeply
mixed boundary layer to the west of the Laramie Range. Look for a
few isolated storms to build up late this afternoon or early evening
over the Laramie Range but coverage should not be too widespread.
Guidance still indicates that storms may be able to maintain
themselves into the overnight hours as lift from a mid level wave
passing to the north may aid in providing lift above the cooling
boundary layer. Should any sustained updrafts develop, deep layer
shear of 40 to 50 kt along with steep mid level lapse rates could
allow for some large hail in the strongest storms.
Surface winds shift to northerly on Saturday as a pre-frontal trough
sets up from northern CO into the NE panhandle. Convection appears
to be most likely along this trough over the southern Panhandle and
along the actual cold front pressing south into Converse and
Niobrara Counties late in the day. Models indicate showers and
storms increasing in coverage through the overnight hours on
Saturday night as low level convergence/frontogenesis in the
presence of steep mid level lapse rates are in place over the plains
along a slow moving front. NAM is putting out some hefty rainfall
totals however think models may be overdoing the coverage an
intensity of the convection so tempered POP and QPF a bit.
Sunday looks to be much cooler and cloudy. Continued chances of
showers and thunderstorms with the surface front nearby and weak
ripples of mid level energy passing overhead.
.LONG TERM...(Sunday night through Friday)
Issued at 159 PM MDT Fri Aug 4 2017
The models are starting to focus on the potential for some
moderate rainfall on Sunday night into Monday morning for
portions of southeast Wyoming mainly south of a Torrington to
Alliance line. This area will be under the right entrance region
of the upper level jet along with a strong shortwave moves through
the northern Plains. Ensembles are even keying in on precipitable
water values creeping to around 1 inch which is slightly above
normal for this time of year. Along with this rainfall will come
some more cool temperatures with afternoon highs on Monday only
climbing to the mid 60s to lower 70s. These temperatures will be
slow to recover on Tuesday and Wednesday as the northwest flow
regime persist. More chances of scattered showers and
thunderstorms are anticipated on these days as well as the low
level moisture/instability continues to linger. The ECMWF, GEM
does try to flatten the upper level flow somewhat next week, which
would provide slightly warmer temperatures. Either way this
pattern looks fairly wet for this time of year.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 608 PM MDT Fri Aug 4 2017
Mainly vfr conditions through the taf period. Isolated showers and
thunderstorms will be possible at most sites through the evening.
There will be enough low level moisture for brief mvfr vis/cigs
around in the hours around sunrise at BFF and AIA. Some sites will
see winds gusting to 20-25 kts through around 03Z.
&&
.FIRE WEATHER...
Issued at 159 PM MDT Fri Aug 4 2017
Critical fire weather conditions currently at
Saratoga, Rawlins, and Laramie early this afternoon and thus the Red
Flag Warning continues and was expanded into zone 308. Guidance
indicates that elevated to critical conditions may again develop
Saturday afternoon especially over western Carbon County. Winds may
not be quite as strong Saturday so conditions will likely not be
quite as widespread. However, enough confidence to issue a Fire
Weather Watch for Saturday afternoon. Sunday through early next
week looks to bring cooler temperatures with increasing moisture so
not expecting any concerns after Saturday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning until 7 PM MDT this evening for WYZ303-304-306-
308.
Fire Weather Watch Saturday afternoon for WYZ303-304-306.
NE...None.
&&
SHORT TERM...DEL
LONG TERM...REC
AVIATION...ZF
FIRE WEATHER...DELHazardous weather outlook, Aug 4, 6:34 AM MDT, 17 hours 55 minutes before
Hazardous Weather Outlook National Weather Service Cheyenne WY 634 AM MDT Fri Aug 4 2017 WYZ101>119-051245- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-Central Carbon County- North Snowy Range Foothills-Southwest Carbon County- Sierra Madre Range-Upper North Platte River Basin-Snowy Range- Laramie Valley-South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 634 AM MDT Fri Aug 4 2017 This hazardous weather outlook is for southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Isolated thunderstorms are expected today, mainly east of Interstate 25. Thunderstorms may contain gusty winds and brief heavy rainfall. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A more active weather pattern is anticipated this weekend through the middle of next week as a cold front stalls across the area. Thunderstorms will be possible each day Saturday through Thursday. .Spotter information statement... Spotter activation will not be required at this time. NEZ002-003-019>021-054-055-095-096-051245- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux- 634 AM MDT Fri Aug 4 2017 This hazardous weather outlook is for portions of western Nebraska. .DAY ONE...TODAY AND TONIGHT Widely scattered thunderstorms are expected by this evening across western Nebraska. Some of these thunderstorms may become strong with small hail, gusty winds, and frequent lightning possible. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A more active weather pattern is anticipated this weekend through the middle of next week. Thunderstorms will be possible each day Saturday through Thursday, especially across the southern panhandle. .Spotter information statement... Spotter activation will not be required at this time.
In the hours before
Special weather statement, Aug 4, 11:25 PM MDT, 1 hour 4 minutes before
Special Weather Statement National Weather Service Cheyenne WY 1125 PM MDT FRI AUG 4 2017 NEZ002-003-095-096-WYZ102-108-050615- Box Butte NE-Dawes NE-North Sioux NE-South Sioux NE-Goshen County WY- Niobrara County WY- 1125 PM MDT FRI AUG 4 2017 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN BOX BUTTE... SOUTHWESTERN DAWES...CENTRAL SIOUX...SOUTHEASTERN NIOBRARA AND NORTHEASTERN GOSHEN COUNTIES UNTIL 1215 AM MDT... At 1125 PM MDT, Doppler radar was tracking a strong thunderstorm over Harrison, or 29 miles east of Lusk, moving east at 35 mph. Dime size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Crawford, Harrison, Flahertys Corner, Fort Robinson Campground and Fort Robinson. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. && LAT...LON 4254 10411 4280 10398 4270 10322 4228 10341 TIME...MOT...LOC 0525Z 288DEG 32KT 4267 10389 Trudel
Special weather statement, Aug 5, 12:29 AM MDT, 0 minutes before
Special Weather Statement National Weather Service Cheyenne WY 1229 AM MDT SAT AUG 5 2017 NEZ095-096-WYZ101-102-107-108-050715- North Sioux NE-South Sioux NE-East Platte County WY-Goshen County WY- Converse County Lower Elevations WY-Niobrara County WY- 1229 AM MDT SAT AUG 5 2017 ...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL SIOUX...SOUTHERN NIOBRARA...NORTHERN GOSHEN...NORTHEASTERN PLATTE AND SOUTHEASTERN CONVERSE COUNTIES UNTIL 115 AM MDT... At 1228 AM MDT, Doppler radar was tracking a strong thunderstorm 10 miles southwest of Lusk, moving east at 40 mph. Dime size hail and wind gusts up to 50 mph will be possible with this storm. This strong thunderstorm will be near... Rawhide Buttes around 1240 AM MDT. Jay Em around 1250 AM MDT. Prairie Center around 100 AM MDT. Other locations impacted by this storm include Hwy 85 At Dry Rawhide Creek and Van Tassell. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. && LAT...LON 4259 10494 4292 10472 4272 10376 4217 10416 TIME...MOT...LOC 0628Z 289DEG 39KT 4266 10461 Trudel
The office that day
Everything else NWS Cheyenne, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 5, 2:41 AM MDT | Red Flag Warning | CYS | 15 hr | |
| Aug 5, 2:39 PM MDT | Special Weather Statement | CYS | Laramie | 36 min |
| Aug 5, 3:13 PM MDT | Severe Thunderstorm Warning | CYS | Laramie | 32 min |
| Aug 5, 3:42 PM MDT | Severe Thunderstorm Warning | CYS | Laramie | 33 min |
| Aug 5, 4:07 PM MDT | Special Weather Statement | CYS | Laramie | 38 min |
| Aug 5, 4:20 PM MDT | Areal Flood Advisory | CYS | Laramie | 3 hr |
| Aug 4, 6:06 PM MDT | Special Weather Statement | CYS | Cheyenne | 39 min |
| Aug 4, 11:25 PM MDT | Special Weather Statement | CYS | Sioux | 50 min |
| Aug 5, 1:20 AM MDT | Special Weather Statement | CYS | Sioux | 40 min |
| Aug 5, 2:17 AM MDT | Special Weather Statement | CYS | Box Butte, Morrill | 58 min |
| Aug 5, 4:20 PM MDT | Special Weather Statement | CYS | Kimball | 40 min |
Nearby
Special Weather Statements in Wyoming, 2017Every special weather statement in 2017
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.