Areal Flood Warning 48, NWS Missoula, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
834 AM MDT THU JUN 23 2011

.UPDATE...COOLED TEMPERATURES OVER THE IDAHO PANHANDLE TODAY. ALSO
MADE SOME ADJUSTMENTS ON THUNDERSTORM COVERAGE TODAY ACROSS
WESTERN MONTANA AND NORTH-CENTRAL IDAHO.

&&

.DISCUSSION...A COLD FRONTAL SYSTEM WILL BE PASSING THROUGH NORTH-
CENTRAL IDAHO AND WESTERN MONTANA DURING THE DAY TODAY. SCATTERED
THUNDERSTORMS WERE ALREADY MOVING INTO THE IDAHO PANHANDLE AND
NORTHWEST MONTANA THIS MORNING IN ASSOCIATION WITH THE FRONT.
THESE AREAS WILL BE THE FOCUS OF CONVECTION DURING THE MORNING
HOURS. WEST-CENTRAL MONTANA AND LEMHI COUNTY WILL SEE THUNDERSTORMS
DEVELOPMENT BY EARLY AFTERNOON AS THE FRONT MOVES ACROSS THIS
PORTION OF THE FORECAST AREA. THESE AFTERNOON STORMS WILL BE
STRONGER IN NATURE WITH THE POTENTIAL FOR SMALL HAIL...GUSTY
WINDS AND BRIEF HEAVY RAIN.

NORTHWEST MONTANA WILL LIKELY SEE A DECREASE IN THUNDERSTORM
ACTIVITY THIS AFTERNOON IN THE LESS UNSTABLE STABLE...DRIER AND
...COOLER POST FRONTAL ENVIRONMENT.

&&

.AVIATION...A COLD FRONTAL SYSTEM WILL BE MOVING THROUGH THE IDAHO
PANHANDLE AND NORTHWEST MONTANA THIS MORNING...THEN ACROSS WEST-
CENTRAL MONTANA AND LEMHI COUNTY DURING THE AFTERNOON. THIS FRONT
WILL BE THE FOCUS FOR CONVECTION WITH SOME STORMS BECOMING QUITE
STRONG DURING THE AFTERNOON HOURS...WITH SMALL HAIL AND GUSTY WINDS.
ALL AIRFIELDS WILL BE IMPACTED BY THIS SYSTEM AS IT PASSES THROUGH
THE AREA. SHOWER AND THUNDERSTORM ACTIVITY IS ANTICIPATED TO
DIMINISH THIS EVENING AS THE FRONT MOVES INTO CENTRAL MONTANA.

&&

.PREV DISCUSSION... /ISSUED 333 AM MDT THU JUN 23 2011/

DISCUSSION...A MID LEVEL DISTURBANCE MOVED THROUGH THE NORTHERN
ROCKIES LAST NIGHT CAUSE WIDESPREAD SHOWERS AND THUNDERSTORMS.
BEHIND THIS FEATURE THE ATMOSPHERE WILL REMAIN FAIRLY UNSTABLE
ALLOWING FOR THE DEVELOPMENT OF MORE SHOWERS AND POTENTIALLY
THUNDERSTORMS THIS MORNING. THE MODELS ARE STILL INDICATING A COLD
FRONT SWINGING THROUGH THE NORTHERN ROCKIES LATER TODAY. THIS
FRONT WILL HELP WITH THE DEVELOPMENT OF THUNDERSTORMS. THE
STRONGEST STORMS ARE STILL ANTICIPATED FOR LEMHI COUNTY UP INTO
SOUTHWEST MONTANA. BEHIND THE FRONT GUSTY WESTERLY WINDS WILL MIX
TO THE SURFACE. THESE WINDS COULD CAUSE CHOPPY CONDITIONS ON
FLATHEAD LAKE. AT THIS TIME SUSTAINED WINDS ARE NOT ANTICIPATED TO
EXCEED 20 MPH SO A LAKE WIND ADVISORY WILL NOT LIKELY BE NEEDED.

THE SHOWER AND THUNDERSTORM ACTIVITY IS ANTICIPATED TO DIMINISH
THIS EVENING AS THE FRONT MOVES OFF INTO CENTRAL MONTANA AND WE
START LOSING SOLAR HEATING. THE NORTHERN ROCKIES WILL REMAIN UNDER
A WESTERLY FLOW AS A LOW PRESSURE SYSTEM MIGRATES EASTERLY IN
SOUTHERN CANADA. THIS FLOW PATTERN WILL KEEP TEMPERATURES FAIRLY
COOL ON FRIDAY...AROUND 10 DEGREES BELOW NORMAL.

SATURDAY THROUGH WEDNESDAY...A TROUGH OF LOW PRESSURE MOVING ALONG
THE CANADIAN BORDER WILL BRING THE POTENTIAL OF SOME RAINFALL OVER
THE WEEKEND. THE LACK OF MOISTURE WITH THIS SYSTEM WILL LIMIT THE
POTENTIAL FOR RAINFALL. A TROUGH OF LOW PRESSURE DIGGING ALONG THE
WEST COAST WILL HELP TEMPORARILY AMPLIFY A SHORT-LIVED RIDGE OVER
THE NORTHER ROCKIES. THIS RIDGE WILL BREAK DOWN AS THE TROUGH
MOVES INLAND WEDNESDAY OR THURSDAY.

NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW.

&&

NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW.

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

SHORT TERM...MSJ
LONG TERM....LOEFFELBEIN
AVIATION...MSJ