552
FXUS65 KBOI 260559 CCA
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1155 PM MDT Tue Jun 25 2024

...CORRECTION TO AVIATION DISCUSSION...

.DISCUSSION...The leading edge of moisture arriving from Nevada
has crossed into far SE Oregon/SW Idaho this evening. Radar
shows isolated high-based showers with the initial surge, but
better moisture will move into southern areas overnight
accompanied by scattered showers and isolated thunderstorms.
The showers/thunderstorms expand in coverage on Wednesday.
Afternoon heating will enhance the potential for stronger
outflow winds, with some storms capable of producing gusts to
around 50 mph. In addition to the convection, winds increase in
SE Oregon Wednesday afternoon ahead of an approaching cold front
with gusts in excess of 30 mph. No updates.

&&

.AVIATION...VFR. Scattered showers and thunderstorms developing
overnight across SE Oregon and near the ID/NV border, continuing
through Wed afternoon. Outflow gusts 30-45 kt possible. Surface
winds: SE to SW 5-15 kt. Increasing to 10-20 kt with gusts to 25-30
kt in E Oregon and near NV/ID border Wed afternoon. Winds aloft at
10kft MSL: SW 10-20 kt, increasing to 20-30 kt by 26/12Z.

KBOI...VFR. Ceilings lowering to around 10,000 ft AGL overnight. A
30% chance of showers/thunderstorms mainly 25/11Z through 25/18Z,
with outflow gusts of 30-45 kt possible. Surface winds: SE 5-15 kt,
transitioning to NW Wednesday evening.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Thursday night...A shortwave
trough will move into the area tonight, bringing a rare
nocturnal convective event to the region. Storms are expected to
develop after 06Z in SE Oregon, and move into SW Idaho after
around 09Z. These storms will be capable of wind gusts 40-50
mph. Storms will continue into Wed afternoon on the Idaho side,
and wind gusts could approach 60 mph in the strongest storms. PW
values increase tonight, so brief heavy rain is also possible in
the strongest storms. As the system departs Wed afternoon, the
PW will decrease rapidly. Winds will increase, especially in SE
Oregon, Wed afternoon. The combination of lightning and stronger
winds has prompted the issuance of a Red Flag Warning for parts
of the area from late tonight through Wed evening (see the Red
Flag Warning for details).

After tonight`s initial shortwave, a larger upper level trough
will move through Thursday. This will bring very few additional
showers, but much cooler air. After temperatures around 10
degrees above normal tomorrow, readings will be around 5 degrees
below normal Thu and again Fri, with Thu being the coolest day.
Northwest winds Thursday afternoon and early evening will be
gusty (15-25 mph) for most areas, and even stronger in the
upper Treasure and western Magic Valleys (25-35 mph).

LONG TERM...Friday through Tuesday...We will remain dry Friday
until Saturday evening as dry NW flow aloft shifts gradually to
SW ahead of a trough developing off the coast. The trough will
gradually move inland through Sunday and cross our area Sunday
night. As this occurs, a chance of precipitation will return
Saturday evening and increase through Sunday afternoon/evening.
Thunderstorms are possible, especially in the higher terrain
and south of the Snake River. We should dry out Monday and
remain dry for Tuesday.

Saturday will be the warmest day of the long term, with temps
5-10 degrees above normal. Otherwise, temperatures should be
around normal.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from 6 AM to 9 PM MDT Wednesday IDZ401-402.
OR...Red Flag Warning from 3 AM MDT /2 AM PDT/ to 9 PM MDT /8 PM
     PDT/ Wednesday ORZ636-637.

&&

$$

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DISCUSSION...BW
AVIATION.....BW
SHORT TERM...SP
LONG TERM....SP