697
FXUS65 KPIH 270925
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
325 AM MDT Sat Apr 27 2024

.SHORT TERM...Today through Sunday Night.
Early morning satellite imagery shows a H5 low centered around
the Four Corners region as radar imagery continues to show
scattered rain and high elevation snow showers. Hi-res CAMS
remain in good agreement throughout the day today showing showers
this morning transitioning to a mix of showers and thunderstorms
by this afternoon, aided by 200-500 J/kg of SBCAPE and 20-30 kts
of 0-6km shear. Predominant dry conditions outside of isolated
showers across ERN Idaho will then return tonight heading into
Sunday as drier, zonal flow fills in behind this exiting system.

Additional QPF/rainfall amounts today after 6 AM will range from
around 0.10-0.30" in the valleys outside the WRN CNTRL
Mountains/Magic Valley region where less than 0.10" is expected.
Locally higher total are anticipated across the higher terrain
with an emphasis along the Wyoming/Montana border region where
around 0.25-0.60" with locally higher totals along the Continental
Divide are expected. Accumulating snow has been observed at
Willow Creek Summit and Lost Trail Pass over the past 24 hours
which continues to support snow levels around that 6500-7000`
mark.

For Sunday, look for a return to mostly dry conditions as drier,
zonal flow prevails which will keep temperatures consistent with
highs in the upper 40s to low 60s and lows generally above
freezing outside of some our colder mountain valleys. Best chances
for isolated precipitation chances and a slight chance of
thunderstorms Sunday will remain south and east of the Snake Plain
into the higher terrain as any additional QPF amounts remain
light.

With respect to winds through the weekend, they will be strongest
today around the Magic Valley with sustained winds around 20-30
mph and gusts up to 30-45 mph before increasing for Sunday,
shifting NE up the Snake Plain with sustained winds around 15-25
mph and gusts up to 25-40 mph. These breezy winds will be ahead of
a stronger wind event favored to move into our region on Monday
as our next system moves in from the PacNW for early next week.
MacKay

.LONG TERM...Monday through next Saturday.
Main impact in the long term period will be a very strong cold
front moving through eastern Idaho on Monday. Will bring rain and
snow showers but not expecting significant amounts. Winds will be
extremely strong and at least advisory levels in most areas.
Expect widespread 20 to 35 mph sustained speeds Monday afternoon
into early evening with gusts 40 to 55 mph especially in northern
parts of the Snake Plain. Is trending more toward advisory level
than warning level but will play out of the next couple of days.
It will be cool with highs in the 40s mountains with some 30s and
50s valleys. It will dry out Tuesday but blend still has some
isolated to scattered showers with breezy conditions continuing
under strong westerly flow aloft. Another system will increase the
chance of showers once again. It will remain very cool through
Wednesday with highs Tuesday and Wednesday remaining in the 30s
and 40s mountains and lower 50s in the valleys. Model solutions
diverge late next week and early weekend with the blend keeping
some chances of precipitation in the grids with significant
warming by Friday into Saturday with flow aloft becoming more
southerly. Highs by Saturday expected to be in the 60s to near 70
in lower elevations and 50s and 60s in the mountains. GK

&&

.AVIATION...For the 12Z TAFS through 12Z Sunday.
Upper level low passing to south will keep showers going at TAF
sites today with some isolated thunderstorms again this afternoon
but will not go more than vicinity at TAF sites. Expect MVFR to
IFR ceilings at all the sites with worst at DIJ where IFR
conditions have persisted early this morning. Heavier showers will
drop the other sites to MVFR conditions occasionally most of the
morning and early afternoon. Strongest winds at BYI with 10 to 15
knots with gusts 20 to 25 knots. 10 to 15 knots likely at PIH and
IDA. Main impact today will be the showers and low ceilings. GK

&&

.HYDROLOGY...
Water levels remain elevated on the Portneuf River from Pocatello
to Chesterfield Reservoir where River Flood Warnings remain in
effect until further notice. Minor to moderate flooding is ongoing
in this area with both the Pocatello and Topaz river gauges
forecast to crest this weekend before dropping slightly heading
into early next week. Further north and west along the Snake
River, water managers have increased releases from upstream
reservoirs leading to high flows in excess of 10,000 cfs
downstream from Palisades to Milner. The Snake River near Heise
and Snake River at Lorenzo gauges have reached action stage as a
result and are expected to be at that stage until further notice.
Willow Creek below Tex Creek above Ririe Reservoir and the
Blackfoot River above Blackfoot Reservoir both also continue to be
in action stage since Monday with no major impacts seen elsewhere
in our CWA as of Saturday morning. MacKay

&&

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

&&

$$