Areal Flood Advisory 21, NWS Missoula, MT

307 
WGUS85 KMSO 210019
FLSMSO

FLOOD ADVISORY
NATIONAL WEATHER SERVICE MISSOULA MT
619 PM MDT MON AUG 20 2012

MTC029-210027-
/O.CAN.KMSO.FA.Y.0021.000000T0000Z-120821T0030Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FLATHEAD MT-
619 PM MDT MON AUG 20 2012

...THE SMALL STREAM FLOOD ADVISORY HAS BEEN CANCELLED FOR THE GOING 
TO THE SUN ROAD IN NORTHERN FLATHEAD COUNTY...

THE THUNDERSTORM WHICH PRODUCED HEAVY RAIN OVER THE GOING TO THE SUN 
ROAD IN GLACIER NATIONAL PARK HAS MOVED EAST OF THE AREA. NO FURTHER 
IMPACTS ARE EXPECTED.

LAT...LON 4892 11400 4888 11403 4883 11397 4886 11383
      4882 11375 4879 11376 4874 11370 4862 11374
      4859 11367 4859 11355 4856 11350 4856 11351
      4856 11406 4894 11406

$$

Area Forecast Discussion
National Weather Service Missoula MT
321 PM MDT Mon Aug 20 2012

.DISCUSSION...

Anticipate mid summer warmth to continue across the Northern Rockies
through Tuesday, ahead of a weak Pacific storm system. Daytime
heating will allow thunderstorm development to continue mainly
across southwest Montana and central Idaho through this evening. The
previously mentioned Pacific storm system will bring thunderstorm
activity across the region on Tuesday. Some of the Tuesday afternoon
storms along the Continental Divide may produce brief gusty winds.
Otherwise, a mix of somewhat beneficial rainfall and periods of
lightning are the biggest concern at this time. Cooler temperatures
are expected on Wednesday, with high pressure drying the atmosphere
out through Thursday.

Friday a dry cold front moves through the area causing windy
conditions and possibly some dry thunderstorms. This is a strong
system, but there is very little moisture available for it to work
with, so not much precipitation is expected. However, there is a
potential for some dry thunderstorms along the southern edge of
the system near Butte and in Lemhi Co. Idaho. Otherwise, windy
conditions with this system will cause choppy conditions on area
lakes affecting boaters.

The one wet area with this storm will likely be Glacier National
Park on Friday. Snow levels look like they will remain above Logan
Pass for now, but those venturing into the back country should be
prepared for blustery, wet, cold weather in the mountains. Snow
levels will be around 7000 to 8000 feet.

Saturday conditions will improve between systems, but will be
cool. The next system will come early next week, but the forecast
confidence is low due to poor model agreement on timing. However,
this is setting up to be another relatively dry, windy system.

&&

.AVIATION...Showers and thunderstorms will be present across the
Northern Rockies, mainly south of MSO, through 21/0400Z. There is a
slight chance of showers or thunderstorms impacting KSMN or KBTM
during this time, with brief wind gusts developing. Otherwise,
conditions will become more favorable after 21/0400Z. Thunderstorms
will be more numerous and impact all area terminals after 21/1800Z,
with brief gusty winds and frequent lightning the main impact.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...RED FLAG WARNING from Noon MDT /11 AM PDT/ Tuesday to Midnight
     MDT /11 PM PDT/ Tuesday Night Eastern Lemhi County...
     Southern Clearwater Mountains...Western Lemhi County.

&&

Zumpfe/Leach
Aviation...Zumpfe