Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Boise Idaho
849 PM MDT Monday Mar 10 2014
Discussion...thunderstorms developed this afternoon in NE Oregon
and again late today in southwestern Idaho. One strong storm with dime-
sized hail went right over Boise and continued southeastward toward Mountain
Home...spreading hail on Interstate 84 along the way. This
convection was apparently due to rapid cooling aloft and resulting
destabilization. Cooling at the surface tonight will increase
stability and end all storms by 10 PM MDT. As the upper trough
exits to the east...colder northerly flow aloft will follow and halt the
snowmelt through Wednesday. Upper level ridging and dry weather
with daytime temperatures only slightly above normal will continue through
Friday. A weak wave will come through Friday evening followed by
even stronger ridging for the weekend with warm dry weather...
Aviation...MVFR-IFR showers and isolated thunderstorms winding down
with loss of daytime heating. Expect clearing after 06z. Mountains
obscured tonight. Snow levels near 4500 feet mean sea level. West/northwest surface winds
15-25kt with gusts to 35kt decreasing to 10-15kt after 06z Tuesday. Winds
aloft at 10k feet mean sea level...northwest 35-45kt becoming NE 15-25kt after 18z Tuesday.
Fog/stratus development possible near kmyl after 12z. Winds expected
to inhibit fog development elsewhere.
Hydrology...Weiser river crested at Cambridge /cami1/ at 13.3 feet
at 6 PM vs flood stage of 12.0 feet. Weiser river at Weiser /wsri1/
should crest at 11.4 feet around midnight tonight vs flood stage
there of 9.5 feet. After that the Weiser river as well as other
rivers will recede as precipitation ends and snowmelt stops due to colder air
short term...tonight through Wednesday...the Pacific storm that
brought over 2 inches of rain to the Weiser basin and locations in
the Boise and west central mountains will exit to the east overnight.
Northwest flow on the back side of the trough will keep snow showers
going across the SW Idaho mountains through Tuesday morning with an
additional 1 to 3 inches accumulation above 4k feet. Without the
orographic component valleys will dry out tonight. Drying continues
on Tuesday as leftover mountain shower activity dissipates before noon.
North to northeast flow will keep a cool airmass in place and
temperatures near normal Tuesday. An upper ridge builds over the
area Wednesday bringing mostly clear skies and warming temperatures
several degrees from tuesdays highs.
Long term...Wednesday night through Monday...predominantly dry
conditions Wednesday night through Monday as a strong Pacific Ridge
builds inland. A series of upper level short waves will move east
along the Canadian border throughout this same period...but impacts
to local weather will be minimal. The upper ridge will further
amplify this weekend for a warming trend through Sunday. Expect high
temperatures to reach middle 60s across lower valleys Sunday afternoon.
Four to six degrees cooler Monday as the next Pacific wave moves
inland...suppressing the ridge.
Idaho...Flood Warning until 7 am MDT Tuesday morning on the Weiser river
at Cambridge idc003.
Flood Warning until 11 PM Tuesday evening on the Weiser river at
Small stream Flood Advisory until midnight tonight in Adams and
Washington counties idc003-087.
previous short term...dg
previous long term....Mt