Flash Flood Watch 1, NWS Missoula, MT

914 
WGUS65 KMSO 150222
FFAMSO

FLOOD WATCH
NATIONAL WEATHER SERVICE MISSOULA MT
822 PM MDT SAT JUL 14 2012

IDC059-150330-
/O.CAN.KMSO.FF.A.0001.000000T0000Z-120715T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LEMHI-
822 PM MDT SAT JUL 14 2012

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR A PORTION OF NORTH CENTRAL IDAHO HAS
BEEN CANCELLED. 

THUNDERSTORM RELATED FLASH FLOOD THREATS HAVE ENDED AS
THUNDERSTORM COVERAGE HAS LESSENED. LIGHTER RAIN SHOWERS ARE
EXPECTED THROUGH THE EVENING.

$$

Area Forecast Discussion
National Weather Service Missoula MT
837 AM MDT Sat Jul 14 2012

.UPDATE...Dried out Clearwater Mountains, Lemhi county of Idaho
through Missoula/Bitterroot valley early this morning.

&&

.DISCUSSION...A dry slot has made its way into portions north
central Idaho and west central Montana this morning. This is
bringing a reprieve in the showers and has allowed some fog to
develop in valleys that did receive rain overnight. The reprieve
is expected to be short lived as another surge of moisture is
moving up from southern Idaho and waves spinning around the upper
low currently over north central Oregon. Expect showers and
embedded thunderstorms to develop across north central Idaho and
western Montana by late morning and continue through tonight.
Again, heavy rain is likely under any cells that develop that may
cause local ponding of water in urban areas and debris/mud flows
in steeper terrain and recent burn areas.

&&

.AVIATION...A slow moving cutoff low west of the region continues
to pump moisture into the Northern Rockies. Showers will increase
this morning, and embedded thunderstorms can be expected by noon.
Northwest Montana will be hardest hit with precipitation, but all
terminals can expect to be impacted by thunderstorms and showers.
Thunderstorms are expected to be slow moving with lower ceilings,
gusty winds, and heavy rain.

&&

.PREV DISCUSSION... /ISSUED /

...Heavy showers possible with thunderstorms today...

DISCUSSION...A heavily moisture-laden air mass has moved over the
Northern Rockies...and will greatly impact the weather this
weekend. The moisture has been brought up from the south by a
nearly stationary upper low over northwest Oregon. This air mass
is very unstable and has supported thunderstorms over northwest
Montana through the night. Abundant lightning and brief heavy rain
has been the main threat from the stronger cells. An automated
sensor in Libby picked up nearly two-thirds of an inch in less
than an hour. Intense rain with the thunderstorm cores will
continue to be a primary threat through the weekend, particularly
over northwest Montana. These type of intensities could cause
ponding on roadways and in urban areas, as well as debris flows in
susceptible locations such as recently burned areas and steep
banks along roads.

The showers, along with a somewhat cooler air mass associated with
the Pacific Coast low, will also keep daytime temperatures
noticeably cooler than this past week.

A second upper low will drop along the Canadian coast Sunday,
ejecting the first low over northwest Montana. Thus, that will
continue to be the focus area for the heavy rain shower threat.

The second low will hang along the Pacific Northwest Coast
through much of the week. There doesn't look to be as much
available atmospheric moisture in the coming week, but with energy
and instability spinning off the upper low, thunderstorms will
continue in the forecast. Temperatures will warm through the week
in the southerly flow aloft ahead of the coastal system, however,
they are not expected to equal the heat of the past week.

&&

AVIATION...A slow moving cutoff low west of the region continues
to pump moisture into the Northern Rockies. Showers will increase
this morning, and embedded thunderstorms can be expected by noon.
Northwest Montana will be hardest hit with precipitation, but all
terminals can expect to be impacted by thunderstorms and showers.
Thunderstorms are expected to be slow moving with lower ceilings,
gusty winds, and heavy rain.

&&

.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