Flash Flood Warning 27, NWS Cheyenne, WY

815 
WGUS75 KCYS 090214
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
814 PM MDT Sat Jul 8 2023

WYC015-027-090224-
/O.CAN.KCYS.FF.W.0027.000000T0000Z-230709T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Niobrara WY-Goshen WY-
814 PM MDT Sat Jul 8 2023

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN NIOBRARA AND NORTHERN
GOSHEN COUNTIES IS CANCELLED...

The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.

LAT...LON 4278 10412 4271 10415 4271 10420 4261 10420
      4261 10449 4284 10458 4284 10433

$$

Trudel

Area Forecast Discussion
National Weather Service Cheyenne WY
529 PM MDT Sat Jul 8 2023

.SHORT TERM...(This evening through Sunday night)
Issued at 200 PM MDT Sat Jul 8 2023

Severe convection ongoing this afternoon. Concerns deal primarily
with the severe convection today...followed by warmer/drier
weather Sunday into next week.

Currently...Convection developing along a line from
Scottsbluff...northwest to Lusk this afternoon. Thinking maybe
this is along an old outflow boundary line from this mornings
convection. This area is also where skies cleared out early and
SBCAPES are up near 2000J/KG.

As the afternoon draws on...expecting low clouds to clear across
southeast Wyoming with instability increasing to 2000 to 2500J/KG.
0-6km shear is definitely there with 40-45kts and mid level lapse
rates 7-9C/KM. Looking like latest HRRR simulated radar is
handling these storms pretty good. Storms moving from northwest to
southeast and stay discrete across southeast Wyoming. So all
modes of severe weather can be expected. Current 0-3km helicity
across the southern Panhandle currently around 250 m2/s2...so this
area would be the best area for tornado development. HRRR
simulated radar shows storms continuing through 03Z this evening
before decreasing in coverage and intensity.

Much warmer and drier Sunday as upper high moves over the CWA.
ECMWF/NAM showing a few storms down here across Laramie County
and the south Laramie Range. Looking at afternoon highs climbing
into the upper 70s and low 80s area wide.

.LONG TERM...(Monday through next Saturday)
Issued at 403 AM MDT Sat Jul 8 2023

Heading into the work week conditions will largely dry out and heat
up as the overall synoptic pattern changes. An upper-level ridge
sitting over the Rockies on Monday will usher in drier air from the
west as well as warmer 700 mb temperatures. This ridge stays in
place for most of the week, however, it will start to flatten out
and turn into more zonal flow midweek, leading to breezy conditions
across much of the CWA. During this time, temperatures will be on
the warm side with highs in the 80s and 90s. Tuesday will likely
be the warmest day of the week with temperatures in the upper 80s to
mid 90s, which is about 5 degrees above average. Precipitation
chances Monday through Wednesday look minimal, however, an isolated
thunderstorm or two during the afternoon hours cannot be ruled out
as disturbances move through the flow aloft.

The forecast becomes trickier towards the end of the week as both
the GFS and ECMWF suggest a cold front dropping down from the north
Thursday afternoon. High temperatures on Thursday will likely be
cooler than the first half of the week, however, temperatures will
depend on timing and strength of the front; details which are still
uncertain at this time. Storms will be possible with this front
since lift and jet energy will be present, but the better moisture
looks to remain north of the CWA. Friday will see the return of
cooler temperatures behind the front. Temperatures will likely be
below average with high in the 70s to low 80s. Flow aloft also makes
the shift back to northwesterlies, leading to more favorable
conditions for storms.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 521 PM MDT Sat Jul 8 2023

Wyoming TAFS...A passing weather disturbance and a moist
atmosphere will help produce a chance of thunderstorms at Cheyenne
through 02Z with gusts to 35 knots, visibilities near 4 miles and
ceilings near 4000 feet AGL, along with thunderstorms in the
vicinity at Rawlins and Laramie. Ceilings will lower to 1500 feet
AGL with areas of fog and visibilities near 2 miles at Cheyenne
from 08Z to 15Z. Otherwise, ceilings will be broken at 3500 feet
AGL in Cheyenne until 08Z. Clear skies will prevail at all
terminals after 15Z Sunday.

Nebraska TAFS...A moist atmosphere and a passing weather
disturbance will produce a chance of thunderstorms at Scottsbluff
and Sidney until 02Z with wind gusts to 35 knots, visibility to 3
miles and ceilings from 2500 to 3500 feet AGL. Thunderstorms will
be in the vicinity of Alliance until 03Z. Scattered clouds around
10000 feet AGL will prevail at Chadron and Alliance after 03Z. At
Scottsbluff and Sidney, expect broken clouds at 5000 feet AGL
until 10Z, then areas of fog with visibilities from 2 to 4 miles
and ceilings from 1500 to 2500 feet AGL until 14Z, then scattered
clouds at 5000 feet AGL.

&&

.FIRE WEATHER...
Issued at 200 PM MDT Sat Jul 8 2023

Active afternoon with showers and storms ongoing east of the
Laramie Range. Look for storms to continue through mid evening
before decreasing in coverage and intensity. Much drier Sunday
into Monday as a high pressure center currently located over
eastern Utah and western Colorado moves into the area. Very dry
for Carbon and Albany Counties Sunday through Tuesday next week
with increasing fire weather threats. Breezy to windy conditions
Monday through Wednesday across Carbon and Albany Counties with
gusts 30-40 mph and afternoon humidity well below 15 percent.
Given fuels are not ready...this may keep fire weather concerns
at bay.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

SHORT TERM...GCC
LONG TERM...SF
AVIATION...RUBIN
FIRE WEATHER...GCC

Special Weather Statement
National Weather Service Cheyenne WY
530 PM MDT Sat Jul 8 2023

WYZ118-119-090015-
Central Laramie County WY-East Laramie County WY-
530 PM MDT Sat Jul 8 2023

...A strong thunderstorm will impact portions of southeastern Laramie
County through 615 PM MDT...

At 530 PM MDT, Doppler radar was tracking a strong thunderstorm near
Hillsdale, or 15 miles northeast of Cheyenne, moving southeast at 25
mph.

HAZARD...Winds in excess of 30 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Burns, Hillsdale and Carpenter.

This includes Interstate 80 in Wyoming between mile markers 378 and
395.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
southeastern Wyoming.

&&

LAT...LON 4127 10465 4137 10447 4127 10407 4100 10429
      4100 10434
TIME...MOT...LOC 2330Z 299DEG 27KT 4124 10453

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH

Dewey

Preliminary Local Storm Report
National Weather Service Cheyenne WY
542 PM MDT Sat Jul 8 2023

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

0350 PM     Tstm Wnd Gst     7 W Lodgepole           41.15N 102.77W
07/08/2023  M60 MPH          Cheyenne           NE   Mesonet

            UPR site SUNOL1. Gust 63 mph at 355PM.

&&

GCC

Special Weather Statement
National Weather Service Cheyenne WY
546 PM MDT Sat Jul 8 2023

WYZ102-090030-
Niobrara County WY-
546 PM MDT Sat Jul 8 2023

...A strong thunderstorm will impact portions of southwestern
Niobrara County through 630 PM MDT...

At 545 PM MDT, Doppler radar was tracking a strong thunderstorm near
Lance Creek, or 25 miles northwest of Lusk, moving south at 35 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Lance Creek.

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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
east central Wyoming.

&&

LAT...LON 4317 10487 4321 10458 4287 10431 4278 10476
TIME...MOT...LOC 2345Z 338DEG 29KT 4308 10470

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

Trudel

Special Weather Statement
National Weather Service Cheyenne WY
550 PM MDT Sat Jul 8 2023

WYZ118-119-090015-
Central Laramie County WY-East Laramie County WY-
550 PM MDT Sat Jul 8 2023

...A strong thunderstorm will impact portions of south central
Laramie County through 615 PM MDT...

At 550 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles south of Hillsdale, or 17 miles east of Cheyenne, moving
southeast at 25 mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Ranchettes.

This includes Interstate 80 in Wyoming between mile markers 369 and
377.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
southeastern Wyoming.

&&

LAT...LON 4123 10475 4127 10465 4100 10434 4101 10458
TIME...MOT...LOC 2350Z 307DEG 23KT 4111 10446

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

Dewey

Preliminary Local Storm Report
National Weather Service Cheyenne WY
615 PM MDT Sat Jul 8 2023

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

0555 PM     Hail             Bill                    43.21N 105.26W
07/08/2023  M1.75 inch       Converse           WY   Public

&&

Special Weather Statement
National Weather Service Cheyenne WY
629 PM MDT Sat Jul 8 2023

WYZ106-107-117-118-090100-
East Platte County WY-
Central Laramie Range and Southwest Platte County WY-
Central Laramie County WY-South Laramie Range Foothills WY-
629 PM MDT Sat Jul 8 2023

...A strong thunderstorm will impact portions of northwestern Laramie
and south central Platte Counties through 700 PM MDT...

At 629 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles west of Chugwater, or 24 miles south of Wheatland, moving
southeast at 25 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of northwestern
Laramie and south central Platte Counties.

This includes Interstate 25 in Wyoming between mile markers 41 and
50.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
southeastern Wyoming.

&&

LAT...LON 4174 10519 4178 10504 4164 10468 4148 10512
TIME...MOT...LOC 0029Z 317DEG 21KT 4170 10505

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Dewey