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Area forecast discussion 
National Weather Service Cheyenne Wyoming 
154 am MDT Thursday Jul 24 2008 


Update...updated gridded forecasts and zone forecasts for 
thunderstorms moving east across Carbon County Wyoming. Rubin 


&& 


Previous discussion... /issued 115 PM MDT Wednesday Jul 23 2008/ 


Short term...tonight through Thursday night...moist airmass remains in 
place over much of far southeast Wyoming into the Nebraska pnhndl. Heating has been 
slowed some in the pnhndl due to morning clouds...but most areas getting 
good sunshine at midday. Low level convergence zone has shifted east 
to along the County Warning Area border from cdr-sny. Moisture plume in middle levels 
has remained over southeast Wyoming into the pnhndl...with first batch of storms 
going up in this band off the northern Colorado mountains/foothills and moving 
generally east-northeast. Cap will break in the pnhndl later this afternoon and 
expect a box over mainly eastern parts of the area. Water vapor 
satellite pictures show a weak ftr over Utah at midday moving NE. Ftr 
appears to be associated with a weak jet streak on the east side of the 
Pacific northwest upper trough which is coming ashore. Models continue to show 
storms breaking out over western/northern sections of the area later this 
afternoon and overnight due to this ftr. Considered a Flash Flood 
Watch but looks like the flow aloft especially over central/northern sections 
has increased quite a bit since yesterday in wake of upper trough that moved 
through overnight mainly to our north. Storms will be slowest moving in 
the southeast qtr of the area. After tonight's storms...expect 
another round of storms for Thursday...although may not be quite as widespread 
as the last few nights. Low level moisture remains in place and in fact 
may be spreading westward on east-northeast winds Thursday afternoon into the Laramie range 
foothills. Models again consistent on showing some lingering showers 
or storms late into the night on Thursday mainly northestern part of area. 
With decent heating in the morning through early afternoon...temperatures on 
Thursday should be similar to today...still on the warm-hot side. 


Long term...Friday through Wednesday....the longwave ridge will 
begin to strengthen on Friday...but not enough to quash the 
instability that will be brought on by surface heating...along with 
both upslope and monsoonal moisture. Scattered storms are a good bet 
that afternoon. Saturday should see more of the same only warmer. 
By Sunday the middle and upper levels will be warm enough to cap most 
activity...so have lowered probability of precipitation to only slight chance. Models 
remain aligned...even ensemble members are narrowly spread...through 
the long term. High confidence in further building western Continental U.S. 
Ridge that will make the 90s degree mark likely all next week in 
Cheyenne...with triple digits likely in portions of the Panhandle. 
Isolated storms will depend on ripples in the flow...so have 
included slight chance each day. 


Aviation...brief MVFR visibilities in stronger thunderstorms mainly over the pnhndl 
this eveng...with some patchy MVFR ceilings forming late tonight and 
lingering early Thursday morning again mainly affecting cdr...bff and sny. 


&& 


Cys watches/warnings/advisories... 
Wyoming...none. 
NE...none. 


&& 


$$ 


Update...Rubin 
long term....sowko