Hail and Damaging Winds in Idaho, August 1, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
240 PM MDT MON AUG 1 2005

.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...MOISTURE HAS STREAMED
INTO WESTERN MONTANA AND NORTH CENTRAL IDAHO UNDER SOUTHWEST FLOW.
DAYTIME HEATING HAS ALLOWED THE ATMOSPHERE TO BECOME UNSTABLE THIS
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP ACROSS THE REGION. A COLD FRONT ASSOCIATED WITH AN UPPER
LEVEL TROUGH IS PUSHING ITS WAY ACROSS EASTERN WASHINGTON AND CENTRAL
OREGON THIS AFTERNOON. THIS FRONT IS EXPECTED TO MOVE INTO THE AREA
TONIGHT...THEN STALL OVER THE MIDDLE OF THE FORECAST AREA. THIS FRONT
WILL PUSH THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS TO THE
SOUTHEAST. THUNDERSTORMS ARE EXPECTED TO LINGER THROUGHOUT THE NIGHT
AND INTO TOMORROW MORNING IN THE SOUTHERN PORTION OF THE FORECAST
AREA AS MID LEVELS REMAIN FAIRLY UNSTABLE. MIN TEMPERATURES TONIGHT
WILL BE QUITE MILD DUE TO THE CLOUD COVER. TOMORROW THE TROUGH AXIS
WILL MOVE OVER THE AREA...PUTTING THE BEST POTENTIAL FOR
THUNDERSTORMS IN TO SOUTHWEST MONTANA AND LEMHI COUNTY. THE 850
MILLIBAR TEMPERATURES WILL COOL SEVERAL DEGREES TOMORROW DUE TO THE
PASSAGE OF THE TROUGH. WHICH...IN TURN...WILL COOL MAX TEMPERATURES
TOMORROW SEVERAL DEGREES COMPARED TO TODAY. TUESDAY NIGHT ANOTHER
RIDGE WILL BUILD OVER THE PACIFIC NORTHWEST. THE RIDGE WILL SLIDE TO
THE EAST...BRINGING WITH IT DRIER AIR. THIS WILL CAUSE THE CLOUD
COVER TO DECREASE AND MIN TEMPERATURES TO COOL SIGNIFICANTLY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY...GFS AND ECMWF IN GOOD
AGREEMENT FOR WEDNESDAY WITH UPPER LEVEL RIDGE MOVING OVER THE
REGION. AN ISOLATED THUNDERSTORM OVER THE HIGHER TERRAIN OVER THE
FAR SOUTHEASTERN PORTION OF THE FORECAST AREA WILL BE POSSIBLE WITH
SOME RESIDUAL MOISTURE THERE. SURFACE HIGH BUILDS INTO NORTH CENTRAL
MONTANA WEDNESDAY MORNING BEHIND DEPARTING CANADIAN TROUGH. THIS WILL
USHER IN A COOLER AIRMASS TO THE REGION AS WELL AS SOME UPSLOPE
STRATUS AND A FEW SPRINKLES ON THE EASTERN SLOPES OF GLACIER NATIONAL
PARK AND POINTS SOUTH. BREEZY EAST WINDS A GOOD BET FOR MOST AREAS OF
WESTERN MONTANA WEDNESDAY MORNING THROUGH THE EARLY AFTERNOON...
ESPECIALLY CANYONS. FOR THURSDAY...HOT AND DRY CONDITIONS RETURN FOR
THE ENTIRE AREA. LOW TO MID 90S WILL BE COMMON MOST VALLEY AREAS WITH
TEMPS IN THE LOW 80S AT PASS ELEVATIONS. RIDGE AXIS MOVES EAST OF THE
REGION LATE FRIDAY AS A NEGATIVELY TILTED UPPER TROUGH DIGS SOUTH
TOWARD THE AREA FROM WEST-CENTRAL BRITISH COLUMBIA. ECMWF DEEPER WITH
SATURDAY NIGHT SYSTEM BUT BOTH MODELS QUITE DRY GIVEN SYSTEM
TRAJECTORY. MAIN DIFFERENCE WOULD BE HIGH TEMPS FOR SUNDAY. ECMWF
WOULD SUGGEST HIGH TEMPS ABOUT 5 TO 10 DEGREES F COOLER THAN GFS.
DECIDED TO GO WITH TEMPS SOMEWHAT COOLER THAN MAV GUIDANCE...GIVEN
THE RUN TO RUN CONSISTENCY OF THE ECMWF MODEL.

&&

.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP ACROSS THE WESTERN MONTANA AND NORTH CENTRAL IDAHO THIS
AFTERNOON AND EVENING. THE SHOWERS AND THUNDERSTORMS WILL DIMINISH
AROUND SUNSET IN NORTHWEST MONTANA TONIGHT. WHILE THE SOUTHERN HALF
OF THE AREA WILL SEE THUNDERSTORMS LINGER THROUGHOUT THE NIGHT.

&&

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

SHORT TERM...SMITH
LONG TERM...CHURCH
AVIATION...SMITH
weather.gov/missoula

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MISSOULA MT
554 PM MDT MON AUG 1 2005

IDZ005-006-009-010-MTZ005>007-043-030000-
NORTHERN CLEARWATER MOUNTAINS-SOUTHERN CLEARWATER MOUNTAINS-
WESTERN LEMHI COUNTY-EASTERN LEMHI COUNTY-
MISSOULA/BITTERROOT VALLEYS-BITTERROOT/SAPPHIRE MOUNTAINS-
BUTTE/PINTLAR REGION-BLACKFOOT REGION-
454 PM PDT MON AUG 1 2005 /554 PM MDT MON AUG 1 2005/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
MONTANA AND NORTH CENTRAL IDAHO.

.DAY ONE...TONIGHT
POTENTIAL FOR STRONG EARLY EVENING THUNDERSTORMS IN WESTERN MONTANA
AND LEMHI COUNTY OF NORTH CENTRAL IDAHO...WHICH MAY CONTAIN LARGE
HAIL AND ISOLATED DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.