Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Boise Idaho
845 PM MDT Wednesday Jul 29 2015
Discussion...clear skies and light winds expected to last through
the night. No changes to previous thinking.
Aviation...VFR. Clear skies. Light winds up through 10k feet mean sea level.
short term...tonight through Friday...negatively-tilted upper
level ridge will expand northwestward from The Four Corners
region into the area through the period. This will keep the area
dry through Friday and also bring above normal temperatures.
Moisture remains south and west through the period though high
clouds will begin to increase Friday afternoon across southeast Oregon.
Temperatures will be a few degrees above normal Thursday
increasing to 5-7 degrees above normal /near 100 degrees in the
Treasure valley/ by Friday.
Long term...Friday night through Wednesday...the very warm upper
level ridge over the intermountain region will keep temperatures
above average through the period. The hottest days will be over the
weekend...with highs close to 100 throughout most of the Snake River
Valley. A gradual downward trend will commence on Monday...as the
ridge weakens and monsoon moisture brings enough cloud cover to
lower maximum temperatures a few degrees. Isolated thunderstorms are
possible as early as Saturday afternoon over eastern Oregon...the
central Idaho mountains...and the Nevada border area...but models
show only marginal moisture and instability at best Friday night
through Sunday. Also...it is still too soon to place much confidence
in model resolution and timing of shortwaves which would act as
forcing mechanisms. However on the larger scale there is better than
average agreement on timing an upper level trough as it moves over
northern b.C. Monday night and begins to affect the northwest states
on Wednesday. So for Tuesday and Wednesday we are showing increasing
chances and wider coverage of showers and thunderstorms.
previous short term...jds
previous long term....jt/jc