Tornado Warning 5, NWS Glasgow, MT

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
318 PM MDT MON AUG 5 2002

.SHORT TERM...TROUGH OVER PACIFIC NORTHWEST FORCING SOUTHWEST FLOW
ALOFT OVER MONTANA. MOIST EAST/SOUTHEAST SURFACE FLOW OVER EAST
MONTANA PRODUCING DEW POINTS IN LOWER 60S...BUT WIDESPREAD STRATUS
KEEPING TEMPERATURES OVER CWA IN UPPER 60S/LOWER 70S...EXCEPT FAR
SOUTHWEST WHERE CLEARING PERMITTING 80S. SURFACE TROUGH OVER CENTRAL
MONTANA. SPC SLIGHT RISK...ADJACENT TO MODERATE RISK WEST CENTRAL
MONTANA...DUE TO SHORT WAVE APPROACHING IN UNSTABLE SOUTHWEST FLOW.
12Z MESO ETA ADVERTISED A WEAKER WAVE ACROSS SOUTHEAST MONTANA THIS
AFTERNOON...BUT NOTHING PRESENTLY EVIDENT. SPECIAL 18Z GGW SOUNDING
SHOWS STRONG CAP...WILL TAKE CONSIDERABLE UPPER DESTABILIZATION TO
BREAK. CURRENT THINKING PLACES CONVECTION LATER THIS EVENING AFTER
INITIATING OVER SW MONTANA WHERE CURRENTLY CLEAR...ALLOWING FOR FULL
INSOLATION AHEAD OF SHORT WAVE. WILL MAINTAIN CURRENT THINKING FOR
FIRST PERIOD...WITH POTENTIAL FOR SEVERE...BUT WILL NOW INCLUDE
POTENTIAL FOR HEAVY RAINFALL DUE TO PRECIPITABLE WATER OVER 1.1
INCHES. FLASH FLOOD GUIDANCE PRETTY HIGH...OVER 3 INCHES OVERALL...
SO LIMITED RISK. OVERALL PATTERN LITTLE CHANGED TUESDAY...BUT
SURFACE TROUGH DISPLACED TO EAST MONTANA BY MESO ETA...ALLOWING
GREATER WARMING. SIGNS OF FRONTOGENESIS OVER CENTRAL MONTANA...
SERVING AS FOCUS FOR ADDITIONAL CONVECTION WITH FRONTAL PASSAGE
DURING THE EVENING WEST ZONES...OVERNIGHT EAST ZONES. CONVECTIVE
POTENTIAL LITTLE CHANGED...CHANCE FOR SOUTHWEST ZONES TUESDAY
AFTERNOON SPREADING ACROSS BULK OF CWA TUESDAY NIGHT. WEDNESDAY...
WEAK SURFACE HIGH BUILDS ACROSS MONTANA AS UPPER TROUGH SLOWLY
TRANSLATES TO INTERIOR PACIFIC NORTHWEST...BUT MOIST AND UNSTABLE
SOUTHWEST FLOW FAVORS LOW SCATTERED CONVECTION LATE WEDNESDAY
SOUTHWEST ZONES INTO WEDNESDAY NIGHT ELSE. THURSDAY...SLOW
PROGRESSION OF UPPER TROUGH INTO WEST MONTANA KEEPS SOUTHWEST FLOW
ACROSS CWA...BUT DRIER AND COOLER SURFACE AIRMASS WILL LIMIT
CONVECTION...AND DO NOT EXPECT ANY TO BE SEVERE. WILL STAY CLOSE TO
MOS TEMPERATURE GUIDANCE...MET AND MAV PRETTY CLOSE...WITH TUESDAY
WARMEST DAY AND GRADUAL COOLING AFTER.

.LONG TERM...EXTENDED AVN PROGRESSIVE WITH TROUGH...TAKING INTO
WESTERN DAKOTAS BY LATE FRIDAY. CHANCE OF A FEW SHOWERS LINGERING
OVER EASTERN ZONES FRIDAY. ELSE...FLAT UPPER RIDGE BUILDS INTO
WESTERN CONUS SATURDAY. TROUGH EXPECTED TO DIG SOUTH FROM CANADA
LATE SUNDAY WITH COLD FRONT...BRINGING NEXT ROUND OF PRECIPITATION
LINGERING INTO MONDAY. TEMPERATURES EXPECTED TO BE NEAR NORMAL.   DNS

KGGW TTT 062/087 062/084 059/083 86424333
     BBTB 059/078 054/084 053/084 053/084 8611000320
KGDV TTT 063/089 063/086 060/085 86424333
     BBTB 060/080 054/085 055/084 055/084 8621001330

.GGW...NONE.

MTZ016>027-059>062-061200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
550 PM MDT MON AUG 5 2002

...SEVERE THUNDERSTORMS POSSIBLE LATE THIS EVENING AND TONIGHT...

STRONG SOUTHEASTERLY SURFACE WINDS HAVE TRANSPORTED WARMER AND MORE
UNSTABLE AIR INTO NORTHEAST MONTANA...AS A TROUGH OF LOW PRESSURE
APPROACHES FROM THE SOUTHWEST. THIS LOW LEVEL MOISTURE...COMBINED
WITH STRONG WINDS IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE HAVE
CREATED AN ENVIRONMENT CONDUCIVE FOR SEVERE THUNDERSTORMS.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHERN MONTANA THIS
EVENING ALONG A FRONTAL BOUNDARY...AND MOVE NORTHEAST INTO NORTHEAST
MONTANA THROUGH THE LATE EVENING AND OVERNIGHT HOURS. BECAUSE OF THE
DEGREE OF INSTABILITY PRESENT...STRONG WINDS AND LARGE HAIL ARE
POSSIBLE WITH STRONGER THUNDERSTORMS. HEAVY RAINFALL IS ALSO
POSSIBLE...DUE TO HIGH AMOUNTS OF MOISTURE IN THE ATMOSPHERE.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA SOURCES FOR
LATER STATEMENTS AND POSSIBLE WARNINGS.

KLEINSASSER