Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Boise Idaho
921 am MDT Friday Sep 19 2014
Discussion...much clearer skies today as winds aloft have become
westerly and no longer bring smoke from the King fire in calif.
We expect continued slow improvement through Saturday then greater
improvement Sunday as an upper low comes in from Nevada with
southeasterly and then easterly winds aloft. As noted in previous
discussion...today will be a little cooler under weak troughing
aloft...but Saturday will be warmer again as upper ridge replaces
the trough. No precipitation until Sunday when the Nevada upper low comes
in with a chance of showers and thunderstorms in Idaho zones. Oregon
zones will stay dry. Current forecast looks good...no updates.
Aviation...mostly clear skies and unlimited visibility over
southwestern Idaho and southeastern Oregon today...with the
exception broken stratus clouds with bases near 6000 feet mean sea level vicinity kbke
until 20z. Light surface winds 10 kts or less. Winds aloft will be northwest 20
to 25 kts.
short term...today through Saturday...slightly cooler and
noticeably clearer skies today as westerly flow keeps smoke from
the King fire over California/Nevada and takes 4-7f degrees off yesterday/S
high temperatures. While the arimass remains moist...the
increased stability will keep showers from developing this
afternoon. The upper ridge amplifies over the Pacific northwest on Saturday
driving temperatures back up the 4-7f degrees we lose today. The
airmass dries out while low level winds remain out of the west-northwest
and upper level winds out of the N-NE. Though large fires remain
in Oregon the smoke activity has been less than those in northern
California...thus will see less smoke in the area over the next 36 hours.
Long term...Saturday night through Thursday...an upper level low
pressure system in California will move to the northeast and reach
southern Idaho on Sunday...then push east of the region Monday
night. The system will bring a chance of showers and thunderstorms
to southwest Idaho and portions of southeast Oregon /not including
Baker or Burns/ Sunday and Monday. Temperatures will be above normal
west of the low track /which includes most of southeast Oregon/...
and near normal close to the low track /which includes most of SW
Idaho/ owing to the clouds and showers. A drier southwest flow
follows the departing system for Tuesday and Wednesday as a large
upper trough approaches the West Coast. The trough is prognosticated to
approach the area by Thursday...accompanied by cooler temperatures
and a chance of showers.
previous short term...dg
previous long term....bw