Area Forecast Discussion Issued by NWS Pocatello, ID
000
FXUS65 KPIH 182059
AFDPIH
Area Forecast Discussion
National Weather Service Pocatello ID
259 PM MDT Mon Mar 18 2024
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
High pressure (a Rex block)...centered just west of our
CWA...remains firmly in control of SE Idaho weather, supporting high
confidence in dry, mostly sunny/clear, low-impact conditions with
generally light winds and high temps running as much as 10-15
degrees above normal for mid-March. A SOLID taste of spring! A
slight warming trend continues each day. Observed highs continue to
solidly overperform NBM guidance which has been slow to accurately
latch onto the warming trend, so the focus of forecast edits this
afternoon was again to massage afternoon temps higher each afternoon
(used a composite max of yesterday`s observed highs and the NBM,
then blended toward the NBM 50th percentile which is running closer
to the observed warming trend). Also massaged overnight snow levels
down based on sfc temps, although no precip is forecast until at
least Wed eve/Wed night. - KSmith
.LONG TERM...WEDNESDAY THROUGH NEXT MONDAY...
High temperatures Wednesday will run similar to Tuesday`s highs,
peaking for the week around 10-15 degrees above climatological
norms. The Snake Plain, eastern Magic Valley, and valleys further
south will span the 60s while the mountains and highlands will
range 40s and 50s. The ridge of high pressure over Idaho will
weaken as a low descends into the Pacific Northwest. A shortwave
will pass to our north and flatten the ridge on Thursday with flow
aloft becoming zonal. Slight chances for mountain snow showers
and valley rain associated with the wave ahead of the main low
will arrive as early as Wednesday. It`s not until Saturday that
precipitation chances will become widespread as the trough axis
moves onshore. However, much variation still exists amongst
ensembles regarding the timing, depth, and overall orientation of
the trough beginning this weekend. EPS 72-hour QPF indicates
around 0.15 to 0.40 inch in our valleys with 0.50 to 1.30 inches
in our highlands and mountains. Much of the region will observe
this falling as rain through Saturday as temperatures look to
remain well above freezing across most of the CWA, but snow levels
will drop below valley floors by Sunday. - Cropp
&&
.AVIATION...
VFR conditions with mostly clear skies and light winds forecast
throughout the period as high pressure remains in control through
mid- to late week. - Cropp
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$