Hail in Idaho, June 25, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
223 PM MDT FRI JUN 25 2010

.DISCUSSION...A WEATHER DISTURBANCE WILL INTERACT WITH A VERY
MOIST AND UNSTABLE ATMOSPHERE AND SUPPORT LOCALLY HEAVY RAIN
SHOWERS FROM THE SOUTHERN CLEARWATER MOUNTAINS EASTWARD ACROSS
LEMHI COUNTY...AND FROM GEORGETOWN LAKE EASTWARD ACROSS ANACONDA
AND BUTTE INTO THIS EVENING. THE MAIN POTENTIAL CONCERNS SHOULD BE
SMALL STREAM FLOODING...PONDING...AND POSSIBLE DEBRIS FLOWS IN
LEMHI COUNTY. IN THE GEORGETOWN LAKE THROUGH ANACONDA AREA...THE
PRIMARY CONCERN IS THE STREAMS...MANY OF WHICH ARE ALREADY NEAR
BANKFULL. IN THE BUTTE AREA...THE MAIN POTENTIAL CONCERN IS RAPID
RUNOFF AND PONDING OF WATER IF HEAVY RAIN IMPACTS THE CITY. NOT
ALL AREAS WILL BE HIT. HOWEVER...THERE IS A SIGNIFICANT POTENTIAL
FOR LOCALLY HEAVY SHOWERS IN THE GENERAL AREA DESCRIBED ABOVE. THE
SHOWERS SHOULD DECREASE AND SHIFT MAINLY EAST OF THE DIVIDE LATE
IN THE EVENING.

FURTHER TO THE NORTH ACROSS THE REMAINDER OF WESTERN MONTANA AND
NORTH CENTRAL IDAHO...THE ATMOSPHERE HAS BECOME QUITE UNSTABLE
FRIDAY AFTERNOON. HOWEVER...THE AFTERNOON STORM COVERAGE SHOULD
BE MORE SCATTERED AND PRECIPITATION AMOUNTS LESS.

HIGH PRESSURE WILL BUILD RAPIDLY OVER THE REGION SATURDAY AND
SUNDAY WITH WARMING TEMPERATURES AND A DRY PERIOD. THE MAIN
IMPACT DURING THIS PERIOD WILL BE ASSOCIATED WITH SOME MODERATE
WEST WINDS SATURDAY AFTERNOON AND IMPACT TO LAKE RECREATION...
ESPECIALLY FLATHEAD LAKE.

HIGH PRESSURE SHOULD FURTHER AMPLIFY OVER THE NORTHERN ROCKIES AND
SUPPORT THE WARMEST TEMPERATURES OF THE YEAR SO FAR BY MONDAY. AS
THIS UPPER FLOW AMPLIFIES...IT WILL ALSO PUT NORTH CENTRAL IDAHO
AND WESTERN MONTANA UNDER AN INCREASINGLY MOIST AND UNSTABLE
ATMOSPHERE AGAIN...ESPECIALLY TUESDAY INTO WEDNESDAY.

WEDNESDAY...SOUTHWEST FLOW CONTINUES OVER THE REGION AS A LONGWAVE
TROUGH BEGINS TO PUSH INTO THE NORTHERN ROCKIES. A COMBINATION OF
GOOD DYNAMICS AND INCREASING MOISTURE SHOULD LEAD TO SHOWER AND
THUNDERSTORM DEVELOPMENT AHEAD OF THIS INITIAL PUSH. THIS FEATURE
BEARS WATCHING SINCE SOME STORMS COULD BECOME STRONG...HOWEVER
TIMING DIFFERENCES COULD AFFECT THIS POTENTIAL SO JUST A MENTION
DISCUSSION-WISE AT THIS TIME.

THURSDAY THROUGH JULY 4TH WEEKEND...DAYTIME TEMPERATURES BEHIND
WEDNESDAYS PRECIPITATION PUSH ARE EXPECTED TO COOL TO ROUGHLY 10
DEGREES BELOW SEASON NORMALS AS THE NORTHERN ROCKIES SITS UNDER A
PERSISTENT TROUGH. PULSES OF ENERGY AND MOISTURE SHOULD STREAM
THROUGH THE REGION WITH BRIEF PERIODS OF DRYING...HOWEVER EXACT
TIMING CANNOT BE NAILED DOWN DUE TO MODEL INCONSISTENCIES.

&&

.AVIATION...A PACIFIC WEATHER DISTURBANCE WILL INTERACT WITH THE
ALREADY UNSTABLE ATMOSPHERE OVER NORTH CENTRAL IDAHO AND WESTERN
MONTANA TO PRODUCE SHOWERS AND THUNDERSTORMS IN THE EVENING. THE
MAIN IMPACT SHOULD BE FROM THE CENTRAL AND SOUTHERN CLEARWATER
MOUNTAINS EASTWARD ACROSS THE SAPPHIRES...PINTLARS...AND BUTTE
AREA. A FEW OF THE STORMS WILL PRODUCE HEAVY RAIN AND OBSCURE
MOUNTAINS. A DRYER WESTERLY FLOW SHOULD DEVELOP LATE TONIGHT INTO
SATURDAY WITH SKIES GRADUALLY CLEARING.

&&

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

SHORT TERM...BAUCK
LONG TERM....BAUCK
AVIATION...BAUCK