Area forecast discussion...updated
National Weather Service Pocatello Idaho
628 am MDT Wednesday may 22 2013
Update...we went ahead and started the lake Wind Advisory now as
winds are already hitting the low end thresholds for this impact. Keyes
&&
Previous discussion... /issued 327 am MDT Wednesday may 22 2013/
Discussion...a closed low continues to basically sit and spin
along the West Coast...occasionally sending waves of energy around
it across Idaho. There is also a lot of dry air embedded within
this storm. This will lead to some areas getting a better chance
of showers and storms followed by a quick end to things. For
today...favored development will be across portions of the central
and eastern mountains by afternoon. A cold front will continue to
push out of the area...with gusty south/southeast winds ahead of
it and southwest to northwest behind it. 15-25 miles per hour winds with
higher gusts will be common especially behind the front. This will
cause of bigger waves on American Falls Reservoir...so we have a
lake Wind Advisory out from middle morning until sunset. While no
severe storms are expected we could see some gusty winds and/or
small hail with stronger activity. The highest instability is
forecast to be in the eastern mountains so that would be the most
likely place for strong storms. Highs today will actually just a
bit below average for late may...50 and 60s for the valleys. Some
light and wet snow is possible generally above 7000ft today but
should not amount to much and likely melt on impact during
daylight hours. For tonight...the models are consistent with
developing a band of showers and evening storms across the eastern
ranges of the central mountains southward to the Utah border.
Other activity is expected to continue farther east with a low
chance even across the snake plain. This band will shift northward
tonight and by morning there will be only a slight chance of
showers closer to The Divide. Snow levels will be in the
6500-8000ft range overnight so anywhere form a trace to a couple
of inches will be possible across the central mountains. It will
melt after sunrise tomorrow. For Thursday and Friday...the low
will send another impulse through and then the whole system will
begin to lift northeast by Friday. A chance of showers and storms
will persist across the western half of the forecast area and
upper snake Highlands Thursday...then mainly across the
central/northern mountains Friday. It will be occasionally breezy
during the period and highs will remain at or just below average
through this period. Lows will be in the 30s and low 40s for the
lower valleys...but we should stay away from frost/freeze issues
it appears.
Looking ahead to the Holiday weekend through early next week...it
will remain unsettled across the area. There will be a chance of
showers and storms remaining across northern and western portions
of the forecast area through Sunday. This is in response to southwest
flow ahead of the next storm which finally moves into the area by
Memorial Day. The models are not quite agreeing with how far south
to bring the main storm as it crosses the state. For now...we are
maintaining a chance of precipitation everywhere with higher
probabilities across the north. It will be warmer into early next
with highs in the 70s to near for the lower valleys. The higher
valleys and mountains should be in the 50s and 60s for the most
part. Do be prepared for some colder mornings in higher terrain especially
across central mountains. Keyes
Aviation...cold front working across eastern Idaho early this
morning. Showers have developed along the cold front and will
continue to shift east with the front into Wyoming through the
morning then redevelop this afternoon and evening mainly north of a
line from ksun to krxe. Conditions will remain mainly VFR with these
showers...though some of the higher elevation areas may see MVFR
ceilings. Gusty winds are expected to redevelop behind the front
through today with gusts reaching 25-30kts in some areas.
Improvement in wind speeds is expected this evening as the surface
flow turns to the northwest and the gradient slackens. Dmh
Fire weather...a deep Pacific low will remain centered over
Oregon/Washington for the next several days. Passage of a cold front
this morning will bring showers and thunderstorms to eastern Idaho
today along with gusty winds. Showers and thunderstorms will
continue into Thursday and Friday mainly over higher elevation
areas. The upper low is expected to lift out of the region by
Saturday...but another system will arrive quickly behind it for
Sunday into Monday. Dmh
&&
Pih watches/warnings/advisories...
lake Wind Advisory until 9 PM MDT this evening idz021.
&&
$$
