554
FXUS65 KMSO 081716
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1116 AM MDT Wed May 8 2024

.DISCUSSION...Moisture previously encircling the primary low
pressure center in eastern Montana is now gradually receding
eastward as the system progresses eastward today. Radar forecasts
indicate lingering showers persisting along the Divide of west-
central and southwest Montana tonight, potentially bringing
sporadic snow showers that could briefly impact mountain passes
like MacDonald and Homestake.

Looking ahead, model clusters and ensemble forecasts are
converging on the development of a modest Rex block/split flow
pattern over the western U.S. by Thursday. In this scenario, the
Northern Rockies will find themselves under the influence of a
warm high pressure ridge, fostering a steady warming trend through
the weekend. Expect valley highs across central Idaho and western
Montana to range from the mid 70s to mid 80s during this period.
Confidence in this forecast is bolstered by the NBM v4.2, which
projects an 80 percent probability for high temperatures below
4000 feet to exceed 80 degrees on Sunday.

However, as we head into early next week, the ensemble mean
guidance suggests the high pressure ridge will begin to flatten,
initiating a cooling trend. Yet, model clusters diverge
significantly on the specifics of the weather pattern, introducing
notable uncertainties in temperature and precipitation forecasts.
This variability translates to a wide spectrum of possibilities,
ranging from continued warmth and dry conditions to a 40% chance
of cooler, showery weather by Wednesday.


&&

.AVIATION...Moisture wrapping around a surface low over central
Montana will continue to spread light valley rain showers across
region, sporadically lowering ceilings at all aviation sites. The
surface low will slowly move eastward, reducing showers across
the Northern Rockies. Shallow fog may develop early tomorrow
morning for KGPI, KMSO and KHRF, along with a low stratus deck.



&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.

ID...None.
&&

$$