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Area forecast discussion 
National Weather Service Cheyenne Wyoming
1134 PM MDT Thursday Jul 2 2015

issued at 920 PM MDT Thursday Jul 2 2015

Scattered showers and thunderstorms are continuing to progress
over Carbon and Albany counties into early tonight. Another area
of isolated showers is developing over Torrington. This is likely
due to middle level instability associated with a weak shortwave
moving overhead. Drier air aloft will move into the area over the
next few hours...along with middle level subsidence which should
cause storms to dissipate by 06z. Other forecast elements are on
track and updates have been sent.


Short term...(this evening through Saturday night)
issued at 251 PM MDT Thursday Jul 2 2015

Widely scattered showers and a few storms developing over parts of
southeast Wyoming this afternoon but not as much as was at this time
yesterday...likely due to less upper support. Should see a bit
more activity develop and move southeast into this evening before
dissipating tonight.

Little change seen in the overall pattern across the region Friday
through Saturday with a northwesterly flow aloft conducting periodic
ripples across the area. Should see widely scattered showers and storms
refire over the mountains Friday afternoon...moving southeast over the plains
through the evening. One feature will be a weak surface trough that
will begin to edge eastward over the High Plains Saturday.
Somewhat drier air behind this should act to reduce convective
activity over southeast Wyoming but may focus it over the Panhandle. Cape
values do go up over the plains Friday...generally in the
1000-1500 j/kg range...and over 2000 j/kg over the Panhandle
Saturday afternoon so a few stronger storms may result. Shear
values not all that high but still decent. Otherwise continued
warm Friday and even warmer Saturday as 700 mb warm about 2-4c.

Long term...(sunday through thursday)
issued at 251 PM MDT Thursday Jul 2 2015

Pretty strong cold front still on track to move into the area
Sunday evening into Monday morning. European model (ecmwf) 700mb temperatures fall
from +16c Sunday morning to +8c Sunday evening. Fairly widespread
showers and thunderstorms Sunday with the approach of this
front...especially Sunday evening. European model (ecmwf) showing well over an inch
quantitative precipitation forecast across the northern Panhandle and Niobrara County Sunday
evening. Did increase probability of precipitation to likely across the northeast.

A pretty cool day for Monday with the cold air behind the front
settling into the area. 700mb temperatures fall to +6c. Continued
to undercut guidance on temperatures. Cheyenne may struggle to
get out of the 60s Monday.

Another Canadian front looks to move into the area Tuesday night
into Wednesday. Pretty strong jet forecast to move into Colorado
Wednesday afternoon ahead of this front. Still looks like a pretty
good day for severe thunderstorms Wednesday afternoon/evening.
Still a ways out though and conditions could change.

Shortwave ridge for Thursday may give US a brief break in
showers. Mountains out west still the favored area for afternoon
and evening convection.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1127 PM MDT Thursday Jul 2 2015

A very few isolated thunderstorms are ongoing over southeast
Wyoming and western Nebraska Panhandle at this time. These storms
are slowly weakening and should die off in the next hour or two.
Mainly VFR across the area tonight but some patchy fog is possible
late tonight into early Friday morning. A few more isolated
thunderstorms are expected tomorrow afternoon.


Fire weather...
issued at 251 PM MDT Thursday Jul 2 2015

Fire weather concerns will remain low for the foreseeable future
with nearly daily chances for scattered mainly afternoon and
evening showers and thunderstorms. Winds will remain generally
light...though briefly gusty around storms. A monsoonal pattern
may set up next week which will keep chances for showers and
storms in the forecast.


Cys watches/warnings/advisories...


long term...gcc

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