textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Potential for a few strong to severe thunderstorms/locally heavy rain threat this afternoon and evening, mainly south of I-90.

- Cooler late this week as daily afternoon showers and thunderstorms continue.

An initial disturbance this morning will bring some showers and perhaps a few thunderstorms, mainly south of I-90. This disturbance will set the stage for the rest of the day, ahead of a secondary disturbance this afternoon. If clouds remain across this area, it will inhibit afternoon thunderstorms which could become severe. Partial clearing will allow for afternoon heating and the potential for a couple strong to severe thunderstorms. Watch for wind gusts to 60 mph, hail and locally heavy rain if stronger cells do form, focused across Lemhi County and southwest Montana.

Speaking of heavy rain, localized flash flooding is a concern near burn scars and flood prone areas, once again focused Lemhi County into southwest Montana. Overall, probabilities are low for flooding due to decent storm motion but there is a 10-20% chance for a burn scar to be hit by rain amounts of 0.50" or greater over an hour this afternoon/early evening.

Thursday through Saturday, the region remains under southwest flow with temperatures still 10 degrees above normal with scattered afternoon thunderstorms. Friday may end up being the best chance for region wide thunderstorms as a disturbance ejects off the broader Pacific trough. The potential remains for a strong to severe thunderstorm or two each afternoon.

There continues to be hints of a precipitation maker around the 17th. About 30 percent of ensemble clusters depict a deeper trough with widespread precipitation. The remainder of the model clusters depict westerly flow which typically is a drier flow at this time of year. More to come on this potential system...

AVIATION

A weak disturbance will produce showers and a few thunderstorms this morning mainly south of I-90. A stronger secondary disturbance follows this afternoon with an increased chance for showers and thunderstorms between 11/1900Z and 12/0100z. There is a potential for a few strong to severe thunderstorms with erratic gusts up to 60 mph, hail and locally heavy rainfall, mainly south of I-90 including near terminals KSMN and KBTM. Much will depend on if cloud cover from the first disturbance lingers into the afternoon, which would inhibit some of the afternoon convective potential.

MSO WATCHES/WARNINGS/ADVISORIES

MT...None. ID...None.