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Area forecast discussion 
National Weather Service Cheyenne Wyoming
316 am MDT Sat may 30 2015

Short term...(today through monday)
issued at 315 am MDT Sat may 30 2015

Pretty quiet weather is expected this weekend as an upper level
ridge strengthens over the western United States. A few thunderstorms
and some showers are expected...mainly on Sunday...but coverage
should be more isolated compared to recently. The main forecast
concern will actually be river flooding in the near term...please
see the hydrology discussion below for more details.

Model soundings show the midlevels becoming drier today as
subsidence develops along a shortwave ridge axis pushing across
the area. However...can not rule out one or two thunderstorms near the
Laramie range this afternoon due to decent low level
convergence...available moisture...and daytime instability. Not
sure if this will be enough to overwhelm the upper level
subsidence...but given recent precipitation trends across the
Front Range this past month...conditions may be more favorable
than models indicate this morning. Either way...coverage will be
very isolated with little impact. will be a
pleasant start to a nice weekend with partly to mostly sunny
skies. High temperatures will rebound into the 60s to low
70s...warmest over the North Platte River Valley. Sunday will be
10 degrees warmer with highs in the middle 70s to middle 80s across
southeast Wyoming...and low to middle 80s across western Nebraska.
Looks to be our first warm Spring day on Sunday. However...there
is a treat of showers and thunderstorms in the afternoon as to be
expected this time of the year. But not very confident that much
will develop due to the lack of convergence across the High
Plains. Kept pop between 15 to 25 percent...with higher values in
the mountains...but went with a slight chance for now instead of
coverage. Previously...models indicated better convergence along
the Laramie range which seems to be lacking in the 00z run.

For Monday...models indicate a more substantial short wave moving
across the area with good low level convergence and ample moisture.
Went with scattered thunderstorms over the High Plains with a
chance of some stronger storms east of i25. Temperatures on Monday
will be very similar to Sunday...and maybe a few degrees warmer
under southwest flow aloft.

Long term...(monday night through friday)
issued at 315 am MDT Sat may 30 2015

A generally SW flow aloft will be over the region early in the
week and become more southerly and somewhat diffluent by Friday as
troffing sets up over the western Continental U.S.. this a favorable pattern
for scattered mainly afternoon and evening showers and tstrms
through the period as impulses ride up over the area and interact
with instability which should be present in the afternoons and
evenings. Short ridging passing over the region Thursday may bring
some lull to convective activity. Otherwise warm temperatures will
settle over the County Warning Area during the week as 700mb temperatures warm to about
12-14c by Tuesday then cool a few degrees for Wednesday and Thursday
behind a weak Pacific front.


Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 315 am MDT Sat may 30 2015

Areas of LIFR visibilities due to fog and IFR ceilings will be over parts of
far southeast Wyoming and the Nebraska Panhandle early this morning. Conditions
there will improve during the morning with VFR expected areawide
by late morning through Sunday morning.


Fire weather...
issued at 219 am MDT Sat may 30 2015

No fire weather concerns this weekend and into next week. A
slightly drier and more stable airmass will move over the
area daytime minimum relative humidity lowers between 25 to 45
percent. However...widely scattered showers and thunderstorms will
quickly return to the area by early next week. Thunderstorms are
expected to increase in coverage as the week progresses.


issued at 219 am MDT Sat may 30 2015

For the Laramie river...Fort Laramie is currently at 8.1 feet and
is forecast to fall to minor flood stage shortly. The river will
likely remain in flood stage through the middle of next week.
Further upstream at Laramie...bankfull conditions will continue
into early next week with a rise to near flood stage late in the
week due to snowmelt runoff.

Along the North Platte river...Henry NE is currently at 5.6 feet and
is forecast to fall below flood stage late tonight. At Mitchell
NE...the river is currently at 8.9 feet and will remain steady
today...and fall slowly by Sunday. Runoff from yesterdays locally
heavy rainfall will keep the river near floodstage at Minatare
through this the stage sits at 7.4 feet early this
morning. Will have to also monitor Bridgeport as the river is
approaching action stage.

Attention then shifts to the snowmelt runoff in the mountains
late this weekend into early next week as temperatures rise into
the 60s to low 70s over the higher elevations. The Upper North
Platte River at Saratoga is forecast to slowly rise and reach
bankfull by early next week.


Cys watches/warnings/advisories...


Short term...tjt
fire weather...tjt

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