567
FXUS65 KPIH 022110
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
310 PM MDT Tue Jul 2 2024

.SHORT TERM...Today and Wednesday.
High pressure will dominate the area today with weak northwest
flow aloft. Expect mostly clear skies and dry conditions outside
of the Montana Divide area. There will be a slight chance of
showers and thunderstorms along the Montana divide late this
afternoon. Winds at the surface have become more westerly but
will remain light overall. Temperatures will be 4 to 8 degrees
below normal this afternoon.

Tomorrow a weak trough will pass over western Montana. Winds will
be breezy especially for our southwestern areas, Eastern Magic
Valley and Southern Hills, where gusts of around 30 to 35 mph are
expected. Most of our western areas will be very dry, with
relative humidity mostly below 15%. See fire weather discussion
for impacts for critical fire weather winds and relative humidity.
There will be a slight chance of mountain thunderstorms in the
Island Park area tomorrow afternoon. Temperatures will increase
slightly tomorrow but remain below normal. There is a lake wind
advisory for the American Falls reservoir for tomorrow afternoon
into the early evening.
Wyatt

.LONG TERM...Thursday through next Tuesday.
Under the increasing influence of high pressure through the extended
forecast period, temperatures will see a gradual warming trend into
next week as conditions remain very dry. Remaining in broad NW flow
through the weekend given the H5 ridge axis placement to our west
and a broad troughing pattern over the CNTRL CONUS, the warming
trend in our area will be suppressed slightly with much warmer
conditions further south and east given the H5 ridge axis placement
not directly overhead us. As this ridge axis shifts overhead late
this weekend into early next week, supported by the majority of
ensemble models and cluster solutions, high temperatures will climb
to the warmest levels seen so far this year. Across our lower
elevations, highs will climb into the upper 80s to low 100s which
will approach near record to record levels across central and
eastern Idaho for this time of year. For reference, normal daytime
highs for this time of year are in the upper 70s to upper 80s in the
valleys which would make this warmth about 10 to 15 degrees above
normal for early to mid July. Little changes in the upper-level flow
pattern will keep this ridge of high pressure in place through all
of next week our hot and dry pattern persisting.
MacKay

&&

.AVIATION...High pressure in light northwest flow aloft will bring
VFR conditions with overall light winds and mostly clear skies
this afternoon into this evening. Winds will become breezy
tomorrow as a trough passes over western Montana. Look for wind
gusts tomorrow afternoon for all TAF sites of around 20 to 30 mph
with KBYI and KPIH having the strongest winds.
Wyatt

&&

.FIRE WEATHER...
Seasonably cool and mostly dry conditions will continue through
Wednesday as a passing trough in Montana helps to introduce
isolated showers and thunderstorms in addition to near critical to
critical fire weather conditions for Wednesday. Elevated winds aloft
and moisture passing along the Continental Divide will be the
primary driver of these hazards with best chances for showers and
storms (10-30% chance) across ERN 475/476, NRN 410, and along all of
411. Winds will be breezy regionwide tomorrow, peaking during the
afternoon with gusts to around 30-45 mph. Given humidities in that 8-
15% range for 425 and 427, the combination of the very dry surface
conditions and winds has led to our first RED FLAG WARNING issuance
of the year which will be in effect from 1200 to 2100 tomorrow. Near
critical fire weather conditions will also exist across lower
elevations of other FWZs with the strongest winds expected across
425/427 and to a lesser extent in 410/413.

Behind this exiting system to our NE in Montana for Thursday,
temperatures will remain seasonably cool aided by prevailing NW flow
aloft. This will be in stark contrast to what is being observed
further southwest of us where a broad H5 ridge of high pressure is
in place which is leading to much warmer conditions. Under the
increasing influence of this high pressure through the weekend, we
will see temperatures gradually warm into early next week with our
position on the ERN periphery doing us a favor in keeping the
warmest temperatures at bay until late this week into early next
week. During that timeframe, the H5 ridge axis will shift directly
overhead which will lead to highs climbing into the 90s to low 100s
for our lower elevations, marking the warmest air mass moving into
our region so far this year. Little changes in the upper-level flow
pattern will keep this ridge of high pressure in place through all
of next week our hot and dry pattern persisting.
MacKay

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 9 PM MDT Wednesday for IDZ425-427.

&&

$$