699
FXUS65 KPIH 110918
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
318 AM MDT Sat May 11 2024

.SHORT TERM...Today and Sunday.
A ridge of high pressure will maintain dry conditions over the
Pacific Northwest through much of the weekend. Models indicate only
up to around a ten percent chance of a stray shower each afternoon
and evening. High pressure will allow for ample sunshine and a
continuation of the warming trend, with daytime temperatures
reaching 5 to 10 degrees above climatological norms today. Winds
will generally remain light today, outside of slightly breezy winds
in the Shoshone area and along the ID-UT border, and again through
much of the day Sunday. Sunday will likely be our warmest day before
the pattern change, with temps reaching into the mid to upper 70s
for our low elevations, 60s in the highlands, and 50s in the high
terrain. Winds will noticeably increase Sunday evening as the ridge
begins to break down and upper flow turns more zonal ahead of an
approaching trough. Precipitation chances will also increase across
the E and SE Highlands beginning late Sunday. Cropp

.LONG TERM...Monday through next Saturday.
Monday marks a change from a stable to unstable pattern as the ridge
breaks down and shortwave troughs swing through Idaho both Monday
and Tuesday. Along with widespread chances of precipitation and
thunderstorms early to middle of next week, elevated 700mb
westerly winds will lead to widespread breezy surface winds each
afternoon. A Wind Advisory may be warranted for a couple of our
forecast zones on Monday, although current forecast speeds are
marginal. Deterministic models depict drastically different
scenarios Wednesday through Friday, with the ECMWF suggesting that
the pattern will remain unsettled through the remainder of next
week and the GFS showing a ridge returning Wednesday.
Interestingly though, the majority of 500mb ensemble cluster
solutions now favor the return of a high pressure ridge mid to
late week, although there are slight timing differences regarding
the departing trough and building ridge. Only about 14% of total
ensemble members favor a continuation of an unsettled pattern
ahead of the next system that will descend from Canada next
Saturday. In spite of the uncertainty amongst models, the National
Blend maintains at least a 75% probability of widespread 70
degree or warmer max temperatures outside of the highlands and
mountains through Friday. Cropp


&&

.AVIATION...VFR conditions forecast with dry conditions and light
winds throughout the period. FEW high clouds will develop early
day, with mid-level clouds increasing during the afternoon to FEW
to SCT. Winds will begin to increase Sunday evening ahead of the
incoming system on Monday. Cropp


&&

.HYDROLOGY...A ridge of high pressure will bring drier and warmer
conditions to East Idaho for the weekend. High flows on area water
ways are expected to continue, especially as warmer temperatures
increase snow melt at upper reaches of the ranges. The Portneuf
and Blackfoot rivers remain the water ways of concern, though
there is some hope that conditions may slowly be improving. Have
maintained the Flood Warnings for the Blackfoot as levels remain
at or above Flood Stage. The Flood Warning remains intact for the
Portneuf at Pocatello. Have rescinded the Flood Warning for the
upper reaches of the Portneuf and issued a Flood Advisory instead.
Current and forecast levels appear to remain just below Flood
Stage, but the river remains elevated. With the pleasant weekend
in store and the continued high levels, opted to maintain at least
some kind of safety message, and wait to see how the temperatures
impact the river going through the weekend. DMH


&&

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

$$