EF0 tornado, (Byi)Burley Muni Arp, Idaho, August 2, 2019

Area Forecast Discussion
National Weather Service Pocatello ID
203 AM MDT Fri Aug 2 2019

.SHORT TERM...Today and Saturday. Another day of storms is on tap
for portions of central and eastern Idaho into this evening. There
is still a pocket of mid level moisture trying to skirt our
western areas, especially the central mountains. That could lead
to a shower or two this morning generally west of 93 and north of
75. As we go into this afternoon, we are watching another weak
"wave" lifting northeast across central Idaho. This will lead to
another round of scattered thunderstorms across that region. With
higher amounts of moisture available for thunderstorms today,
locally for locally heavy rainfall along with gusty winds. Some
small hail is possible with the strongest of storms. At the
moment, we are not expecting the widespread rainfall we saw
yesterday across the Upper Plain extending into the Island Park
area and toward the Big Holes. We should also see isolated
thunderstorms developing across the southern and eastern benches
of the Snake Plain, lifting northward across the Plain toward the
Montana border. Speaking of that area of widespread rain, while
nothing is expected until later this evening up that way...that
higher amount of surface moisture might fuel storms earlier in
the afternoon or fuel more storms that forecast this evening.
Moisture will be more limited overnight and Saturday. The concern
is for isolated dry thunderstorms developing from around Gilmore
Summit and the Lost River Range toward Monida Pass and Island
Park. We may also see a few storms fire across the Marsh Highlands
northeast toward the Big Holes. Otherwise, look for temperatures
running on average 5 degrees above normal.  Keyes

.LONG TERM...Sunday through next Friday. We look to remain in
constant southwest flow with monsoon moisture getting pulled into
the state almost daily. This should help fuel the potential for
showers and thunderstorms. Right now, confidence on pinpointing
coverage or rainfall amounts is low on any given day...but expect
the highlands and mountains to see a better chance overall vs the
Snake Plain. We look actually cool off a bit as we get into next
week, but still running fairly close to average, if not just
above, for August. Keyes

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.AVIATION...Monsoon ridge remains anchored near the 4-corners as a
weak Pacific low pressure system lifts ENE across WRN Canada. The
numerical models continue to produce scattered thunderstorm activity
across the CNTRL mountains while the HiRes convective models are
adding isolated convection along the SE mountains from Oakley to
Inkom to Driggs. We will consider adding VCTS to the KBYI and KPIH
terminals in addition to what is already forecast at KSUN and KDIJ.
Outside of any thunderstorms, conditions should remain VFR. Huston

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.FIRE WEATHER...The monsoon high pressure ridge will remain anchored
near the 4-corners region today as a weak Pacific disturbance lifts
ENE across WRN Canada. The numerical models continue to highlight
scattered thunderstorm activity across the CNTRL mountains today
where a Red Flag Warning remains in effect. HiRes convective models
are indicating the potential for isolated thunderstorms along the SE
mountains from Oakley to Inkom to Driggs as well this afternoon. The
next monsoon push is expected to work north through Utah Saturday
night impacting SE Idaho Sunday, particularly the SE mountains where
moisture levels remain high enough to support widespread wetting
rains with the isolated to scattered thunderstorm activity. Big
question here is whether the monsoon cloud cover will be dense
enough to suppress daytime heating and thunderstorms. Lingering
diurnal thunderstorm activity continues into Monday and Tuesday as a
low pressure system sets up off the Oregon coast with SE Idaho
remaining under the influence of the monsoon ridge still anchored
over the 4-corners region. The pattern does not appear to change
until Thursday, per the operational GFS model, when a much drier SW
flow associated with the low off the coast begins to overspread SRN
Idaho. Drier conditions continue into Friday as the low ejects NNE
through Washington and eventually east along the Canadian border
Saturday. Although stable conditions are anticipated with the
ejecting low...drier humidity and increasing winds will likely
result in increasing fire behavior for ongoing fires. Looking at the
current forecast for Thursday through Friday, it appears that the
National Blend of Models would like to keep a mention of
thunderstorms across the region. We will be watching the trends on
these differing perspectives as we work our way deeper into the
forecast period next week. Daytime temperatures remain above
normal throughout the forecast period. Huston

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon today to 9 PM MDT this evening for
IDZ475-476.

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