719
FXUS65 KPIH 092220
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
420 PM MDT Thu May 9 2024

.SHORT TERM...REST OF TODAY THROUGH FRIDAY NIGHT...
Radar shows scattered showers through parts of Eastern Idaho
early this afternoon with an isolated thunderstorm or two embedded
within. You`ll notice these showers are moving from northeast to
southwest today as a low to our southeast is retrograding back to
the southwest. Just a bit of a departure from our "normal"
direction of showers and storms and they are expected to diminish
after sunset as we loose the heating of the day. No severe weather
is expected, but storms and their outflows could produce gusts
around 40 mph. Speaking of wind, it continues to be breezy (and
windy at times) today, especially across parts of the Mud
Lake/Arco Desert area with forecast winds of 20 to 30 mph and
gusts around 40 to 45 mph where a Wind Advisory remains in effect
until 7 PM this evening.

On the plus side, the general trend is for wind gusts to gradually
decrease and temperatures to gradually increase. However, it will
still be chilly tonight, so will go ahead and issue another Frost
Advisory for the Pocatello and Idaho Falls zones from 3 AM to 9 AM
Friday morning. It will be borderline in the Arco Desert/Mud Lake
area and the Magic Valley will only see lows drop to near 40s, so
will leave these zones out. This will likely be the last frost
advisory we need for a bit as temperatures Friday night and Saturday
morning will be near 40 degrees for most. Afternoon highs will be
warmer on Friday with highs in the mid to upper 60s in the Snake
Plain and pushing into the low 70s in the eastern Magic Valley.
Friday will be breezy at times with gusts 25 to 30 mph, but it all
looks to remain below Wind Advisory criteria. AMM

.LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
We continue to expect the weekend will be dominated by high
pressure, with mostly dry/clear and much warmer conditions. High
temps will range from the mid-60s to mid-70s Sat, and upper-60s to
upper-70s Sun, for most population centers. A low pressure
center...the remnants of our recent cold/wet pattern...will still be
lurking just south of the forecast area, so a low-confidence, low-
end chance of a couple showers or a t-storm still exists across the
srn highlands and Bear Lake region. Allowed some light NBM PoPs to
remain in these areas as we monitor model trends with respect to how
far north that low may be sitting. During the Mon-Tue period, models
are trending toward a stronger/more organized signal for a fresh
shortwave trough to drop across the nrn Rockies, bringing increasing
chances of isolated to scattered showers/t-storms and increasingly
breezy conditions. We`ll likely lose at least a few degrees off of
high temps on the back side of this system, followed by uncertainty
toward the middle of next week as another progressive system may
affect portions of the region. 01

&&

.AVIATION...
One more day featuring a few isolated showers and t-storms is
expected as departing low pressure is still in fairly close
proximity to SE Idaho (slowly sinking south into the Four Corners
region and Nevada). We did go ahead and expand VCSH to KSUN, and
upgraded KPIH, KIDA, and KBYI to VCTS, with refined start/end timing
based on the 12z high-res HREF suite in the 18z TAFs. That said,
confidence is high that cigs/vsbys will remain VFR both today and
beyond. The other main impact will be moderate N/NE winds through
this eve everywhere but KSUN, decreasing in speed after 02-03z/8-
9pm, after which point skies will trend toward clear. Fri is
expected to be dry at the TAF terminals with lighter winds and only
a few clouds. 01

&&

.HYDROLOGY...
Warming temps over the next several days are expected to result in
slight rises on several area rivers. Whatever snowfall was realized
recently at mid-slope is likely to melt off, and temp profiles
support some snowmelt at higher elevations as well. So far, main
flooding impacts still appear confined to the Portneuf and Blackfoot
rivers where FLOOD WARNINGS remain in place, although the Big Lost
River at Howell Ranch could approach bankful early next week.
Remember that flows are high, fast, and cold on waterways across the
region this time of year, as melting mountain snow is still a
significant contributor to these waterways. People recreating
on/near East Idaho rivers and streams are urged to remain cautious,
and keep children and pets away from the water. 01

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM MDT this evening for IDZ052.

&&

$$