Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Cheyenne Wyoming
525 am MDT Thursday Jul 24 2014

Short term...(today through saturday)
issued at 345 am MDT Thursday Jul 24 2014

Current infrared satellite loop shows a continuous stream of cloud cover
extending from Arizona northeastward into Wyoming and Colorado.
This is mainly due to middle to upper level moisture pushing
northward around the strong upper level high currently over New
Mexico and southern Colorado. This cloud cover may result in
limiting surface based convection over the area due to less
surface heating. In addition...slightly lower temperatures than
previously expected in addition to less bl mixing may inhibit fire
weather concerns over portions of the forecast area. Forecast
soundings show cape values below 1000 j/kg and Li/S only between
-1c to -3c. With intervals of cloud cover...this suggests
scattered rain showers with isolated thunder through the day.
Models do show a rather weak shortwave moving northeast during the
day along the Colorado border which may enhance convection during
the late afternoon and evening hours. Do not expect severe thunderstorms
today as drier air attempts to push into central Wyoming. High
temperatures will range from the middle 80s to middle 90s along and west
of i25...with highs around 100 degrees across western Nebraska
and the adjacent plains of far eastern Wyoming.

For Friday...the strong upper level high is forecast to begin
drifting southward. This will allow the monsoon moisture plume to
shift southward as well...with any showers and thunderstorms mainly near
the Colorado border and along the i80 corridor. Drier air aloft will
begin to mix towards the surface across the northern zones from
Douglas to Chadron Nebraska. Kept pop between 20 to 30 percent
from Laramie eastward to southwest Nebraska. High temperatures
will be similar to Friday...but should be noticeably cooler across
the northern zones with highs in the low to middle 90s north of the
Platte River valley.

For Saturday...upper level flow becomes more northwesterly as the
leading edge of a cold front begins to slowly move southward.
Temperatures will lower into the 80s across most of the High
Plains east of the Laramie range with winds shifting into the
east. Models indicate very stable and dry air pushing into the
region. This will greatly limit tstorm chances to the mountains of
Colorado or the High Plains of southeast Colorado.

Long term...(saturday night through wednesday)
issued at 208 am MDT Thursday Jul 24 2014

Saturday night...quiet overnight period with limited low and middle
level moisture.

Sunday...weak northwest flow aloft prevails. Limited low and middle
level moisture...thus mostly dry.

Monday...monsoonal moisture increases slightly...thus will see
isolated late day thunderstorms along the Laramie range and
Interstate 25 corridor.

Tuesday...models forecast and increase in monsoonal moisture...thus will
see a corresponding increase in late day thunderstorm coverage...most
numerous over the mountains.

Wednesday...atmosphere will stabilize slightly...thus less late day
thunderstorm coverage.

&&

Aviation...(for the 12z tafs through 12z Friday morning)
issued at 524 am MDT Thursday Jul 24 2014

VFR prevails. Between 18z and 02z...isolated to scattered
thunderstorms producing localized turbulence and gusty and
erratic winds along with localized MVFR.

&&

Fire weather...
issued at 308 am MDT Thursday Jul 24 2014

Upgraded the Fire Weather Watch to a red flag warning across zone
301...mainly the lower elevations of Converse County. This should
be a rather marginal event due to relatively high dewpoints and
intervals of cloud cover during the day. However...models
indicate a strong surface low developing across South Dakota and
an intensifying low level pressure gradient aiding the idea of
strong westerly winds today. In addition...hot temperatures are
expected across the area with readings approaching the century
mark. Otherwise...the rest of the area will have slightly higher
humidities and a chance of thunderstorms into this evening.

Hot and dry conditions will continue into this weekend before a
cold front moves across the area late Saturday. Humidities will
trend higher by Sunday with much cooler temperatures.

&&

Cys watches/warnings/advisories...
Wyoming...red flag warning from 9 am this morning to 6 PM MDT this evening
for wyz301.

NE...none.
&&

$$

Short term...tjt
long term...Rubin
aviation...Rubin
fire weather...tjt

National Weather Service Glossary of Abbreviations