Wildfire in Idaho, August 3 to 7, 2024

Area Forecast Discussion
National Weather Service Pocatello ID
1023 AM MDT Sat Aug 3 2024

.UPDATE...We put out a quick update this morning, based on trends
in the higher resolution models. Still looks showers and isolated
storms over the central mountains initially this afternoon. Then
showers and isolated storms move in from the south this evening
and overnight, with the bulk of this remaining over higher
elevations. Rainfall will be at a minimum, with a 10-30% chance of
winds over 35 mph this afternoon and evening. We did keep isolated
thunderstorms in overnight, as we will likely see a few random
lightning strikes over the higher elevations.  Keyes

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.PREV DISCUSSION... /issued 308 AM MDT Sat Aug 3 2024/

SHORT TERM...Today and Sunday.
High pressure overhead will allow widespread temperatures to rise
into the mid to upper 90s, although temperatures won't be quite as
warm as yesterday's as the ridge axis shifts slightly east and
increased cloud cover suppresses daytime heating a bit. The Heat
Advisory remains in effect through this evening for our low to mid
elevations where moderate heat risk persists. Remember to take
precautions, especially if you plan to be outside for an extended
period today, and be sure to check on members of vulnerable
populations. A weak shortwave will lift through Idaho tomorrow,
with elevated flow aloft supporting breezy southwesterly surface
winds and 20 to 30 mph gusts across the Snake River Plain. Monsoon
moisture lifted north will allow for isolated thunderstorms as
early as late this afternoon and isolated to scattered showers
through the overnight hours, especially across the central
mountains. Isolated activity will continue again tomorrow,
favoring the Montana Divide region. The strongest thunderstorms
will be capable of producing 40 to 50 mph outflow gusts and small
hail. Expect a 5 to 10 degree drop in daytime highs tomorrow as
this system flattens the ridge. As for smoke, southwesterly/westerly
flow aloft will continue to filter in increased concentrations of
smoke further east into the Snake Plain and therefore, we
continue to carry patchy smoke in the forecast for the next two
days. Cropp

LONG TERM...Monday through Saturday.
Moisture continues to move through the upper ridge early in the
week for continued threat of isolated to scattered thunderstorms
across East Idaho. Models remain consistent in breaking down the
ridge for Wednesday and Thursday. Cooler temperatures and breezy
winds accompany drier conditions. There are some differences in
the GFS and ECMWF this model run with respect to whether the ridge
tries to rebuild over the west, or whether Idaho remains under
the influence of broad shallow trough. Ensembles and clusters
appear to blend the two, allowing for redevelopment of isolated
thunderstorms by Friday while maintaining the cooler temperatures
from the previous forecasts. DMH

AVIATION...VFR conditions persist with high pressure keeping
winds light and variable and conditions dry throughout much of
the day. We continue to forecast HZ/FU, with the HRRR model
showing near surface smoke concentrations increasing across the
Snake Plain, likely resulting in 6SM VIS as far east as KIDA. A
shortwave trough will lift through the region tomorrow, with
clouds increasing ahead of it today and isolated showers and
thunderstorm arriving as early as this afternoon. HREF thunder
indicates less than a 10% chance of thunder at all terminals today
and tonight and precipitation chances should remain around 20% or
less during this same timeframe. Cropp

FIRE WEATHER...One more day of hot temperatures is expected
across the region. Moisture surging north through Great Basin
today, with convection already occurring overnight in Central
Nevada. Expect isolated showers/thunderstorms late today, mainly
across the Sawtooth and Salmon-Challis NFs. Gusty outflow winds
will be possible, then showers continue overnight mainly across
the central mountains. Isolated showers/thunderstorms are expected
Sunday, with continued thunderstorm chances moving into Monday
and Tuesday. Ridge breaks down by Tuesday as stronger shortwave
trough drives through the region. Expect breezy to windy
conditions for the rest of the week, with cooler but drier
conditions. DMH

AIR QUALITY...Regional wildfires continue to impact air quality
over Southeast Idaho with increased concentrations of smoke
expected to filter into the region in southwesterly/westerly flow.
We continue to carry patchy smoke in the forecast over the next
two days, during which the Idaho DEQ is forecasting "Moderate" air
quality. Cropp

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.PIH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM MDT this evening for IDZ051>059-061-062-
065-067-075.

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