Severe Thunderstorm Warning 113, NWS Glasgow, MT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
945 AM MDT THU JUL 24 2008

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
MAIN UPDATES WERE TO TAILOR TODAY/S PRECIPITATION CHANCES WHILE
LOWERING HIGH TEMPERATURES PRIMARILY OVER THE CENTRAL ZONES GIVEN
ONGOING CLOUDS AND PRECIP. LINEAR CLUSTER OF STORMS THAT DEVELOPED
EARLIER THIS MORNING IN GARFIELD COUNTY HAS SINCE SHOWN WARMING
CLOUD TOPS AND OVERALL DECAYING TRENDS AS IT APPROACHES THE MT/ND
BORDER. SATELLITE IMAGERY ALSO CAPTURES A PERSISTENT FEED OF
MOISTURE OVER THE CWA AHEAD OF A VORT MAX IN LOWER ALBERTA...SO
EXPECT PERIODS OF STORMS TODAY UNTIL THIS WAVE CLEARS THE REGION
TONIGHT. INSTABILITY OVERALL WILL BE TEMPERED BY CURRENT CLOUD
DEBRIS WITH THE BEST CHANCES FOR SEVERE WELL SOUTH NEAR A SURFACE
LOW IN NORTHERN WYOMING. MCZ

PREVIOUS SHORT TERM DISCUSSION...
A QUICK MOVING UPPER LEVEL SHORTWAVE SWINGS EAST THROUGH MONTANA
TODAY. COLD FRONT WILL PUSH THROUGH CWA EARLY GENERATING RAIN
SHOWERS WHICH WILL HELP MODERATE MAXIMUM TEMPERATURES TODAY. SMALL
CAPE AND NEGATIVE LI SHOULD SUPPORT THUNDER IN THE MORNING. THE
TROUGH WILL INITIATE CONVECTION BUT WITH PREVIOUS COOLING
EFFECTS...STRONGEST STORMS SHOULD REMAIN SOUTH OF THE CWA WHERE
CONDITIONS WILL BE MORE UNSTABLE. ALTHOUGH AFTERNOON LAPSE RATE
COULD SUPPORT MIXING UPPER LEVEL WINDS TOWARD THE SURFACE...THE
EXPECTED CLOUD COVER SHOULD PREVENT MUCH ACTUAL MIXING. THEREFORE
WIND SHOULD NOT BE STRONG BEHIND THE FRONT. MAXIMUM TEMPERATURES
SHOULD BE HELD TO NEAR NORMAL. SHORTWAVE TROUGH WILL PROGRESS ON
EAST BY LATE EVENING...REPLACED BY HIGH SURFACE PRESSURE AND A
BUILDING UPPER RIDGE IN THE WEST.

THURSDAY NIGHT THROUGH SATURDAY...LINGERING SHOWERS AND TS
THURSDAY NIGHT WILL CLEAR OUT EARLY FRIDAY AS HEIGHT FIELDS
RECOVER JUST DOWNSTREAM OF A BUILDING RIDGE. INCREASING CLEARING
AFTER THE TROUGH EXIT...ALONG WITH INCREASING THICKNESS WILL SEE
TEMPERATURES ONCE AGAIN RISE ABOVE NORMAL BY SATURDAY. HOT AND
RATHER UNSTABLE AFTERNOON WITH MINOR RIPPLES IN THE UPPER FLOW
COULD INITIATE AFTERNOON THUNDERSTORMS SATURDAY. INHERITED SLIGHT
CHANCE POPS LOOK GOOD FOR NOW. SCT

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
UPPER RIDGE CONTINUES TO DOMINATE THE EXTENDED PERIOD WITH HOT
AND MOSTLY DRY CONDITIONS EXPECTED TO PERSIST ACROSS MONTANA.
THERE WILL BE A FEW CHANCES FOR THUNDERSTORMS AS SHORTWAVES WILL
CONTINUE TO EJECT FROM THE GULF OF ALASKA LOW AND TEMPORARILY
KNOCK DOWN THE RIDGE AS THEY RIDE ALONG THE CANADIAN BORDER. ONE
SUCH WAVE EXPECTED SUNDAY OR MONDAY. MODELS DIFFERING ON THE
TIMING AND HAVE BEEN TRENDING LATER WITH THE PASSAGE.

HEIGHTS LOWER SLIGHTLY BEHIND THE SHORTWAVE...BUT WILL QUICKLY
REBOUND AS THE UPPER RIDGE REBUILDS. OVERALL TEMPERATURES WILL BE
ABOVE NORMAL THROUGH THE PERIOD. EBERT

&&

.AVIATION...
MVFR. AN UNSETTLED DAY IS IN STORE TODAY. VISIBILITIES LOOKED TO
BE IMPACTED THE MOST BUT LOCAL CEILINGS DROPPING INTO THE MVFR
RANGE IS NOT OUT OF THE QUESTION TOO. UPPER TROUGH THAT IS MAINLY
RESPONSIBLE MOVING IN FROM THE WEST SHOULD MOVE TO OUR EAST
ALLOWING FOR IMPROVING CONDITIONS THIS EVENING. BETTER CHANCES OF
SEVERE THUNDERSTORMS THIS AFTERNOON ARE LIKELY TO REMAIN SOUTH OF
A JORDAN TO GLENDIVE LINE. JAMBA

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

WEATHER.GOV/GLASGOW