Area Forecast Discussion
Issued by NWS Boise, ID
FXUS65 KBOI 280250
Area Forecast Discussion
National Weather Service Boise ID
850 PM MDT WED JUL 27 2016
.DISCUSSION...A west-northwest flow aloft will continue through
Thursday with an upper high centered over the Southwestern U.S.
This will result in mostly clear skies, light winds, and very
warm afternoon temperatures with highs near 100F in the lowest
valleys once again. Smoke from the Pioneer fire near Lowman will
settle into the valleys overnight and drift into the Boise area
Thursday morning. Northwest winds will return in the afternoon
which should be enough to scour out the smoke. Forecast was
updated earlier to remove mention of showers and thunderstorms in
Baker County and the West Central Mountains this evening.
.AVIATION...VFR with mostly clear skies. Smoke still present near
Lowman due to Pioneer fire. MVFR conditions in the Treasure valley
early Thursday AM due to smoke which will clear out by mid
morning. Surface winds mostly light and variable with afternoon
gusts 10-18kts in the Western Magic Valley. Winds aloft to 10k
feet MSL, westerly 10-20kts.
SHORT TERM...Tonight through Friday...A weak shortwave is visible
on the water vapor satellite imagery, moving across central WA/OR
border this afternoon and into western MT this evening. A slight
chance of thunderstorms will be possible mainly north of a line
from Baker City, OR to McCall, ID this evening. The shortwave will
push east overnight and drier air will push into the region for
Thursday. Expect mostly sunny skies, and light winds on Thursday
with temperatures remaining around 5 to 10 degrees above normal.
Smoke from the Pioneer Fire will continue to reduce visibilities
in the Boise and central Idaho mountains. Smoke will trickle down
the Boise River and Payette River Valleys during the morning and into
the Treasure Valley and Magic Valleys on Thursday and Friday. The
upper level ridge over the Desert Southwest begins to build north
on Friday, bringing slightly warmer temperatures aloft and
monsoonal moisture northward to the Nevada border. A slight chance
of thunderstorms will be possible Friday afternoon and evening along
the Nevada border.
LONG TERM...Friday night through Wednesday...As a trough develops
along the Pacific coast, a southwest flow will continue to bring
monsoon moisture north of the Nevada border and across the region.
This northward moving moisture will largely be marked by increased
cloud coverage through Saturday. Expecting a slight chance of
thunderstorms due to diurnal heating Friday night and Saturday
afternoon/evening as temperatures remain well above normal with
valley temperatures above 100F. Minimal precipitation can be
expected with the anticipated convection through Saturday. The
developing trough will deepen and move eastward Sunday, kicking most
of the monsoon moisture out of the region by Sunday afternoon with
the help of a weak dry cold front early in the day. Temperatures
Sunday will come down about 10 degrees to the seasonal norms.
Forecast expected to remain dry with temperatures near normal
through Wednesday under a zonal flow.
PREV SHORT TERM...KA
PREV LONG TERM....AB/WH