Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 300958
Area Forecast Discussion
National Weather Service Missoula MT
358 AM MDT Wed Jul 30 2014
.DISCUSSION...After a very hot day across the Northern Rockies on
Tuesday, today should be nearly as warm. Once again late this
afternoon, there is a chance for thunderstorms to develop across
southwest Montana and central Idaho. The biggest threat from
storms will be plentiful lightning, gusty winds, and brief, heavy
downpours. Considering that storms that develop today will likely
move very slowly, rainfall that occurs over recent wildfire burn
scarred terrain could result in localized flash flooding. However,
the threat for flooding is fairly low. This same threat will exist
almost every afternoon as we head into the weekend. Those with
recreational activities planned outdoors should have a plan for
lightning, as even the weakest of storms can contain deadly
One interesting feature in the forecast is a heightened surge of
moisture beneath the ridge of high pressure during the Thursday-
Friday time frame. The moisture surge is in response to the remnant
of a tropical storm system being drawn beneath the high pressure.
Previous model runs had maintained a distinct shortwave trough
feature with this system, however the latest model consensus has
focused more on just the moisture in the absence of any storm
features. The surge will be of particular interest because of the
impact of heavy rainfall that may result from such a surge
episode. This is definitely a low-certainty, yet high-impact part
of the forecast.
Aside from the tropical moisture surge, afternoon showers and
thunderstorms will increase in coverage through the weekend and
continue into early next week. The focus of storms will remain
during each afternoon and evenings following mostly stable and
pleasant morning conditions. Continued warm temperatures should
also be expected through early next week, with values remaining
at, or slightly above, normal.
.AVIATION...Today will once again be very similar to that of the day
before: afternoon and evening thunderstorms will be a threat to
mostly KSMN and KBTM between 30/2000Z and 31/0200Z. Breezy north
winds are possible at KMSO and KGPI late this afternoon as well.
Conditions will clear out after sunset with winds diminishing
ID...RED FLAG WARNING from Noon MDT /11 AM PDT/ today to 10 PM MDT /9
PM PDT/ this evening Eastern Lemhi County...Southern
Clearwater Mountains...Western Lemhi County.
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