Tornado Warning 8, NWS Glasgow, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
235 PM MDT MON AUG 23 2004

.SHORT TERM...FOR NORTHEAST MONTANA TONIGHT THROUGH WEDNESDAY...
ONE STORM SYSTEM TO EXIT THE AREA THIS EVENING WITH DRIER WEATHER
LATE TONIGHT THROUGH TUESDAY NIGHT. THE NEXT TROUGH DIGS INTO THE
PACIFIC NORTHWEST WEDNESDAY FOR AN INCREASING CHANCE OF SHOWERS AND
THUNDERSTORMS.  TEMPERATURES WILL AVERAGE A BIT BELOW NORMAL THROUGH
THE MIDDLE OF THE WEEK.

TONIGHT...A SURFACE LOW ACROSS EASTERN MONTANA EARLY THIS AFTERNOON
WILL LIFT OUT OF THE AREA THIS EVENING. THE MID AND UPPER LEVEL
TROUGHS WILL BE SLOWER TO LIFT OUT OF OUR NORTHERN ZONES TONIGHT.
MOST OF THE SHOWERS AND STORMS WILL COME TO AN END THIS EVENING WITH
ONLY ISOLATED SHOWERS LINGERING OVERNIGHT. ONE STRONG TO SEVERE
THUNDERSTORM HAS MOVED ACROSS WESTERN GARFIELD COUNTY THIS
AFTERNOON. POSSIBLE THAT ANY STORMS THIS EVENING ACROSS OUR SOUTHERN
AND EASTERN ZONES COULD TURN SEVERE WITH LARGE HAIL BEING THE
PRIMARY SEVERE THREAT. THERE IS ENOUGH SHEAR THAT AN ISOLATED
TORNADO CAN NOT BE RULED OUT. HAVE INCLUDED THE MENTION OF POSSIBLE
SEVERE FOR THIS EVENING ACROSS ALL BUT OUR NORTHWEST ZONES. EXPECT
THE WIND TO PICK UP IN THE WAKE OF TODAYS SYSTEM. THE ETA HAS ABOUT
30-40KT WIND BETWEEN 700-850H WITH LAPSE RATES AROUND 7C/KM. THE BIG
QUESTION WILL BE HOW MUCH OF THE STRONGER WIND CAN MIX TO THE
SURFACE. THE STRONGEST COLD ADVECTION AND SUBSIDENCE SHIFTS OFF TO
OUR EAST TONIGHT...AND THUS EXPECT THAT MOST OF THE STRONGER WIND
WILL REMAIN ALOFT AND NOT REACH THE GROUND.

TUESDAY...NORTHEAST MONTANA WILL BE IN BETWEEN WEATHER SYSTEMS AND
IT LOOKS LIKE A MUCH DRIER DAY. AN UPPER TROUGH IN THE GULF OF
ALASKA WILL DROP SOUTHEAST TO THE BRITISH COLUMBIA COAST. OUR UPPER
FLOW WILL BACK JUST SLIGHTLY INTO THE WEST/SOUTHWEST WITH WEAK
SURFACE RIDGING ACROSS THE AREA. LINGERED SOME ISOLATED SHOWERS
ACROSS THE NORTHEAST CORNER DURING THE MORNING...BUT WITH A LACK OF
ANY SHORTWAVES VISIBLE ON WATER VAPOR OR DEPICTED BY THE MODELS
DROPPED THE POPS ACROSS THE REMAINDER OF THE CWA. TEMPERATURES
TOMORROW WILL REMAIN A BIT BELOW AVERAGE...BUT WITH WITH CLOUDS
THINNING OUT AND SOME SUNSHINE MOST AREAS SHOULD REBOUND BACK INTO
THE 70S.

TUE NIGHT...THE UPPER TROUGH BEGINS TO WORK INTO THE PACIFIC
NORTHWEST WITH SOME SHORTWAVE ENERGY TO PUSH ACROSS THE NORTHERN
ROCKIES.  THE DEEPER MOISTURE REMAINS TO THE WEST OF THE AREA AND
LOOKS LIKE IT SHOULD REMAIN DRY. CANT RULE OUT THAT A SHOWER WORKS
INTO OUR WESTERN ZONES TOWARD MORNING...BUT FOR NOW WILL LEAVE IT
DRY.

WEDNESDAY...THE UPPER TROUGH CONTINUES TO DIG INTO THE PACIFIC
NORTHWEST WITH SOUTHWEST FLOW ALOFT INTO EASTERN MONTANA. SHORTWAVE
ENERGY WILL BE EJECTED AROUND THE BASE OF THE TROUGH AND INTO
EASTERN MONTANA. EXPECT THAT SCATTERED SHOWERS AND THUNDERSTORMS
WILL WORK FROM WEST TO EAST ACROSS THE AREA...BUT WITH A STRONG
SURFACE LOW LACKING DO NOT ANTICIPATE THE COVERAGE OF THE SHOWERS TO
BE AS GREAT AS THEY WERE TODAY. MADE A FEW TWEAKS TO THE POP GRIDS
TO LOWER THE POPS A BIT DURING THE MORNING IN THE EAST. CLOUDS AND
SHOWERS WILL KEEP TEMPERATURES ON THE COOL SIDE OF AVERAGE. CB

.LONG TERM...WEDNESDAY NIGHT THRU MONDAY...
MODELS RAN INTO POOR AGREEMENT WITH A TROUGH SWINGING THROUGH THE
AREA EARLY IN THE PERIOD. THE GFS OPERATIONAL RUN WAS A BIT SLOW
COMPARED TO ITS ENSEMBLE...WHILE THE ECMWF LOOKED TOO FAST. THE
EXTENDED ETA SOLUTION AT 84 HR LOOKED GOOD WITH A SPEED IN BETWEEN
THE TWO. GOING FORECAST WAS IN LINE WITH THIS SOLUTION AND THEREFORE
WAS NOT TOUCHED TOO MUCH. DRY WEATHER LOOKS TO MOVE INTO THE AREA
WHEN PRECIPITATION LEAVES ON FRIDAY WITH ZONAL FLOW BRINGING IN WEAK
DISTURBANCES. A MORE SIGNIFICANT WEATHER SYSTEM LOOKS TO ARRIVE
ABOUT NEXT TUESDAY.  JAMBA

&&

.KGGW WATCHES/WARNINGS/ADVISORIES...A TORNADO WATCH IS IN EFFECT
UNTIL 8:00 PM MDT FOR SHERIDAN...ROOSEVELT...AND RICHLAND COUNTIES.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GLASGOW MT
211 PM MDT MON AUG 23 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0200 PM     HAIL             7 SE BRUSETT            47.35N 107.16W
08/23/2004  0.88 INCH        GARFIELD           MT   TRAINED SPOTTER

&&

TFJ