Text Products for AFD Issued by PIH

Area Forecast Discussion
Issued by NWS Pocatello, ID
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
000
FXUS65 KPIH 120825
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
225 AM MDT Fri Apr 12 2024

.SHORT TERM...Today and Saturday
The next few days appear to be the warmest that we`ll see for the
next week as our weather pattern looks to return to a more
active, cooler and wetter one. But first, temps today will likely
top out in the lower to mid 70s across our lower valleys with 60s
expected in the high country. The pressure gradient will tighten
across the region today as a trough will move into the western
U.S. later today helping strong southerly flow to become
established over the region. Already seeing some of this this
morning with downslope winds keeping temps around 60 degrees at
PIH.

Later this afternoon, warmer temps and favorable upper level
dynamics may support a period of thunderstorms across eastern
Idaho. The most favorable setup is well to our west across
western Idaho and into Oregon where SPC maintains their "Marginal
Risk" designation for severe thunderstorms. Across our forecast
area, 06Z CAMs remain rather unimpressive and keep the bulk of the
convection to the west of our region. Nevertheless, there will be
some potential across the far western extent of the CWA with the
best chances in the central mountains, especially closer to the
Sawtooths. Bumped up PoPs a bit in this area and have a mention of
thunder but the current feeling is that any stronger storms would
be very isolated in nature. Gusty winds and small hail would be
the greatest concern. Further east, could see some showers (maybe
a tstm) making it into the Snake Plain but without much model
support hard to support PoPs any higher than 20 percent which is
where they are in the current forecast.

Saturday looks mostly dry aside from maybe some high elevation
showers during the afternoon. Temperatures will remain warm for
this time of year with upper 60s and lower 70s likely in the
valleys with those breezy southerly winds continuing once again on
Saturday. Things become more active on Sunday and cooler. More on
that below. McKaughan

.LONG TERM...Sun through Thu night
Through Tue afternoon the agreement even among clusters is
excellent. A closed low will pass through southern NV and UT. This
produces some northerly surface flow and brings a precipitation
threat to a good percentage of central and eastern Idaho. The
colder air apparently stays stable enough so that thunderstorms
are not a consideration, at least at this time. There is very
little precipitation amount when it comes to QPF, just good
coverage. The slow movement means Mon/Mon night has more of the
same. As the northerly surface flow continues, along with the
cloud cover, the temperature goes from the lower to middle 60s in
the lower elevations to around 50 by Tue afternoon. Thus there is
some snow accumulation in the mountains. As this low moves out, a
low moving in from the north slides over the Gem State. This
brings in even colder temperatures as mentioned, and rain and snow
to nearly everywhere. At this point the clusters become more
divergent, with some lingering the closed low on Wed and even Thu,
and they are in the majority, with about 20 percent of the
ensemble moving this low or trough farther eastward. Afternoon
highs Tue-Thu will struggle to get out of the 40s even at low
elevations.

Wind-wise, Sun afternoon appears windy with the storm passing to
the south, and the same for Mon/Mon night and Tue. At this point,
there are some areas in the south that may reach Wind Advisory
criteria (sustained in excess of 30 mph). Mon through Tue looks
windy, but staying below Advisory criteria. Messick


&&

.AVIATION...
VFR conditions likely to prevail for much, if not all, of the
period. Southerly winds will become a bit breezier today compared
to the past few (around 15 kts) with occasional higher gusts.
There is some potential this afternoon and evening for showers,
perhaps thunderstorms, with the best chances at KBYI and KSUN.
Thunderstorm potential appears low based off latest CAMs but
certainly isn`t zero so will maintain VCTS wording for the time
being. If thunderstorms are realized, then certainly some brief,
localized MVFR/IFR conditions will be possible but confidence is
still pretty low at this time. Kept VCSH in for now at KPIH, KIDA
and KDIJ but chances here look quite low. Precip threat will
diminish by late evening and winds will subside closer to 10 kts
during the overnight period with VFR conditions expected.
McKaughan

&&

.HYDROLOGY...
Water levels remain elevated on the Portneuf River in Pocatello
and Topaz where River Flood Warnings and an advisory,
respectively, remain in place. With warm temps continuing for a
few more days, expecting continued mid/high elevation snowmelt
which should lead to rises at both gauges over the days ahead.
Stay tuned for further updates over the days ahead. McKaughan

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$
National Weather Service Regional Headquarters
