Office: BOI
FXUS65 KBOI 191540
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
940 AM MDT Fri Apr 19 2024
.DISCUSSION...A ridge of high pressure will continue to build
over the region today, with warm daytime temperatures
anticipated. Overnight lows will once again dip below freezing
across the area tonight, due to clear skies across the region.
Breezy southeasterly winds will kick up this afternoon,
especially in the Snake River Valley. The forecast has been
updated to increase ridgetop and valley winds this morning,
otherwise, the forecast is on track.
&&
.AVIATION...VFR. Increasing high clouds this afternoon with
mid-level cumulus developing over the higher terrain. Surface winds:
E-SE 5-15 kt, with gusts to 25 kt in the Magic Valley. Winds
aloft at 10kft MSL: SW-NW 5-15 kt.
KBOI...VFR, mostly clear skies. Winds SE 5-10 kt, becoming variable
less than 10 kt around 21Z this afternoon.
Weekend Outlook...VFR and high clouds Saturday. Clouds lowering but
conditions mainly remaining VFR Saturday evening into Sunday, with
isolated MVFR showers and mountain obscuration in Baker County and
West Central Mountains. Decreasing clouds Sunday evening. Snow
levels generally 5500-7500 ft MSL during showers. Surface winds:
SW-SE 5-15 kt Saturday, and W-NW 10-25 kt Sunday.
&&
.PREV DISCUSSION...
SHORT TERM...Today through Sunday night...Warming through
Saturday as a Pacific upper ridge comes inland and over our
CWA. Mostly clear today and tonight then increasing high clouds
Saturday. Low temperatures tonight 33 to 39 degrees in the
southern Idaho agricultural valleys. Pacific cold front will
bring a 20-40 percent chance of rain showers to northern-most
zones Saturday night and clouds to remaining zones. Sunday will
be clearing, windy, and cooler as an upper trough passes north
of our CWA. Clear and colder Sunday night with decreasing west
winds. Lows in the 20s and 30s, with southern Idaho agricultural
valleys between 32 and 38 degrees. Sunny, breezy, and cool
Monday, then clear and not as cold Monday night.
LONG TERM...Monday through Friday...An upper level trough will
move by to our north on Monday as an upper level ridge moves into
the Pacific Northwest. This will keep temperatures near normal
with dry conditions. The ridge will move overhead on Tuesday
with temperatures warming around 10 degrees from Monday. The
pattern will become more active Wednesday through Friday as an
upper level trough approaches our area, although models differ
in timing and strength. Ensembles favor keeping our area in the
warm sector on Wednesday, with temperatures trending cooler
Thursday and Friday as the trough moves inland. Precipitation
chances will increase Wednesday through Friday to 20-50%, with
the highest chances in the mountains. Even with the cooler air
associated with the trough, snow levels are expected to remain
above 5500-6000 ft MSL. Breezy conditions will also accompany
the trough towards the end of the week.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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DISCUSSION...SA
AVIATION.....SA
SHORT TERM...LC
LONG TERM....ST
Office: PIH
FXUS65 KPIH 191004
AFDPIH
Area Forecast Discussion
National Weather Service Pocatello ID
404 AM MDT Fri Apr 19 2024
.SHORT TERM...Today and Saturday.
Current satellite imagery shows mostly clear skies across the
region, although mid-level and high clouds will increase during
the afternoon. We have added light PoPs to the forecast for this
afternoon and evening as high resolution models continue to show
isolated showers across the northern extent of the central
mountains and along a portion of the MT Divide. Accumulating snow
is only expected along the highest peaks though, where up to one
inch will fall through early Saturday. Daytime highs today will
run several degrees warmer than the previous couple of days,
falling around five degrees or less short of climatological norms.
Tomorrow will be noticeably warmer across the region as high
pressure builds in and high temperatures increase by another ten
degrees, give or take. Temperatures will run on the warm side of
normal with the eastern Magic Valley and Snake Plain warming into
the 60s and 40s and 50s in the higher terrain. Cropp
.LONG TERM...Sunday through next Friday.
Deterministic models show a closed low passing to our north
across Canada on Sunday. At this time, the most impactful factor
looks to be the breezy to windy conditions as zonal flow
establishes over Southern Idaho. A Wind Advisory may be needed for
the Snake Plain and potentially the eastern Magic Valley.
Otherwise, we continue to carry low-end PoPs across the eastern
highlands as the system shifts eastward. Models continue to handle
the Monday timeframe a bit differently with subsequent runs and
therefore uncertainty remains if a transient ridge will begin to
build in Monday or later into Tuesday. Either way, a prolonged or
shorter period of low precipitation chances across the high
terrain near the ID-MT border and changes in temperatures would be
the only notable differences. Impacts increase as we head deeper
into the extended timeframe. The next potent low will approach the
US-Canadian border on Tuesday, with models showing it moving
onshore on Wednesday, slightly later than previous model runs.
Winds will increase across much of the region and precipitation
chances will become widespread late week, with Thursday and Friday
being the wettest days. Widespread daytime temperatures in the
40s to 60s will mean mostly rain across the CWA, although
precipitation will fall as snow in the mountains as temperatures
drop into the 20s and 30s overnight. Cropp
&&
.AVIATION...VFR conditions forecast throughout the period. Mostly
clear skies are currently observed over all terminals, with FEW
to SCT mid-level and high clouds forecast to increase beginning
this afternoon. Isolated showers are forecast across the central
mountains but expected to remain north of KSUN. Partial clearing
is expected overnight and early Friday ahead of the next round of
high clouds Saturday afternoon. Winds will remain light throughout
the period, generally remaining 8 kts or less. Cropp
&&
.HYDROLOGY...Water levels on the Portneuf river continue to run
high, just below moderate flood stage for the Portneuf river in
Pocatello. The river forecast for the Portneuf river in Pocatello
shows the river running above flood stage for the foreseeable
future. At Topaz, levels remain and are forecast to remain very
near minor flood stage for the rest of the week. McKaughan
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
