Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus65 kmso 180944 

Area forecast discussion
National Weather Service Missoula Montana
344 am MDT Tue Sep 18 2018

..change to cooler and wetter conditions for portions of western
Montana starting Wednesday...

Discussion...after a chilly start this morning, expect another
nice fall day with temperatures warming into the upper 60s to low
70s in the valleys. A weak Canadian cold front will bring cooler
temperatures and breezy easterly winds to Glacier National Park
and the Flathead Valley late this evening, and Wednesday

A weak mid-level low pressure system is still forecast to bring
increasing chances of rain to portions of western Montana
Wednesday evening, through Thursday morning. Areas with the best
chance for rain, will be the southern Mission Valley,
Missoula/Bitterroot valleys, and southwest Montana. Anywhere from
a tenth of an inch to a quarter of an inch of rain is possible,
especially for the higher terrain.

As the mid-level low pressure system exits to the east during the
day on Thursday, a weak wave of energy will move over northwest
Montana, that will bring rain showers and cooler temperature to
Lincoln and Flathead counties. Only light amounts of rain is
expected, and light mountain snow above 7000 feet.

Friday a weak ridge will influence the area transitioning into
southwesterly flow by Saturday. Sunday the south westerly flow
will allow a short wave trough to move through central Idaho and
North Western Montana. Temperatures Friday and Saturday will be
near normal across the region while Sunday will see temperatures
cooling to mid to lower 60's. Precipitation on Friday will be
restricted to areas close to the Canadian border and higher
elevations. The southwesterly flow on Saturday will expand chances
for precipitation slightly further south with any accumulation
still restricted to more northern and higher terrain areas. Sunday
with the trough passing, will add chance precipitation throughout
the entire forecast area, with highest chance still in higher

We are still watching the potential for a wet Fall storm to
impact the northern rockies by the end of this weekend and the
first part of next week. There still remains some disagreement in
the long term models with the timing and strength. But we at least
expect below normal temperatures and above normal precipitation
to occur.


Aviation...VFR conditions are expected throughout the day, around
0600 local patchy fog could develop in higher valley's, although
visibilities should not be greatly degraded. Typical afternoon
breezes will diminish around sunset.


Mso watches/warnings/advisories...

National Weather Service Glossary of Abbreviations