Scientific Forecaster Discussion
fxus65 kmso 172033
Area forecast discussion
National Weather Service Missoula Montana
233 PM MDT Tue Sep 17 2019
Showers linger mainly along The Divide, but a brief dry period is
on track through the evening. Moisture will begin to move into
north-central Idaho and is expected to become widespread
overnight, ahead of the next trough. Showers will then expand into
northwest Montana during Wednesday morning. Latest forecast
trends show showers to reach the rest of western Montana during
Wednesday afternoon. The main focus for rain is expected to shift
to Lemhi County and west-central/southwest Montana beginning
Wednesday night as the low pressure center organizes. Rain in
these areas should become fairly consistent for most of Thursday,
while the rest of central Idaho and northwest Montana will mainly
see rain showers.
Northwesterly flow is set to develop during Friday, resulting in
showers especially during the afternoon.
Model guidance maintain agreement for weak high pressure to
develop during Saturday, which should result in decreasing
Breezy conditions are possible on Sunday in response to a trough
moving into the Pacific northwest, followed by increased shower
chances for late Sunday and Monday.
Aviation...showers linger along The Divide, but a decreasing
trend is expected with low pressure exiting to the east.
Subsidence over Idaho and western Montana is helping to breakup
cloud cover some, but any clearing will be short-lived with mid-
level moisture forecast to quickly arrive late this evening. Moist
southwesterly flow will move into north-central Idaho overnight
and into northwest Montana during Wednesday morning, bringing
rain and obscured terrain. Showers and obscured terrain will
expand eastward through the rest of western Montana and Lemhi
County by Wednesday afternoon.