Areal Flood Advisory 13, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
313 PM MDT Sat Jul 14 2012

...POTENTIAL FOR SEVERE STORMS ACROSS NORTH CENTRAL IDAHO THIS
AFTERNOON AND EVENING...

.DISCUSSION...The drier air that moved into north central Idaho
and western Montana earlier today effectively cut us off from the
monsoonal flow and the expected widespread showers through much of
the day today. However, with the increased sunshine, the
atmosphere has become more unstable and with the upper low
approaching from central Oregon, the potential for severe storms
exists over north central and southern Idaho. At the same time,
another surge of monsoonal moisture and and upper level wave are
moving north out of southeast Idaho and together with the
approaching upper low potential exists for some localized flooding
over Lemhi county. The above scenarios have been handled by a
severe thunderstorm watch for Clearwater, Idaho and Lemhi counties and
flash flood watch for Lemhi county.

Western Montana will see isolated showers and thunderstorms
through the remainder of the afternoon, but could see more
coverage this evening as things move out of Idaho. Models are
advertising another round of showers and embedded thunderstorms
moving across northwest Montana late tonight as the upper low
approaches. However, the intensities are not expected to be as
strong as last night.

Sunday will continue to be unsettled and continued cool as the
remnants of the first system exit to the northeast. Another upper
low will quickly dive south out of British Columbia late Sunday
and will allow more of a southerly flow to set up over north
central Idaho and western Montana through Monday. This will allow
temperatures to warm back near 90 and keep a threat of
thunderstorms in the forecast. The moisture will not be as
impressive as what is currently moving into the region.

Monday night onward, the models are indicating that the Northern
Rockies will be under southwesterly flow aloft through the next
week. The models are still disagreement on exact timing of
features and moisture through the flow, but every afternoon and
evening appear to have the potential for convection. Temperatures
through next week should be around 5 to 10 degrees above normal.

&&

.AVIATION...A dry slot associated with the low over Oregon has
allowed enough heating that showers and thunderstorms are expected
over much of north central Idaho later this afternoon into this
evening. KSMN could be impacted with heavy rain, hail and gusty
winds with storms from 14/22z-14/03z. Over western Montana,
clearing has also taken place but showers are expected to be more
scattered in nature. KBTM and KMSO could see storms with heavy
rain being the main impact, mainly from 15/00z-15-03z. Another
round of showers is expected to impact northwest Montana
through the overnight hours, but showers are not expected to be as
intense as those seen last night.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1122 AM MDT SAT JUL 14 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0115 AM     TSTM WND DMG     13 SSW KOOTENAI FALLS   48.26N 115.85W
07/14/2012                   LINCOLN            MT   PARK/FOREST SRVC

            FOREST SERVICE REPORTED 20 TREES DOWN BLOCKING THE
            SERVICE ROAD TO THE DORR SKEELS CAMPGROUND AT AROUND 230
            AM. TIME OF POTENTIAL DOWNBURST COULD HAVE BEEN BETWEEN
            100 AND 130 AM MDT ACCORDING TO RADAR.

&&

NOBLE