Severe Thunderstorm Warning 33, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
900 AM MDT FRI JUL 13 2001

WILL UPDATE ZONES TO FRESHEN WORDING...REMOVING MORNING CONDITIONS
AND TO BOOST POPS SLIGHTLY SOME LOCATIONS.

FORECAST ON TRACK WITH AN ACTIVE CONVECTIVE DAY EXPECTED. MODELS
STILL HAVING SOME DIFFICULTLY PLACING AND TRACKING DISTURBANCES...
MESOETA SEEMS TO HAVE THE BEST AGREEMENT WITH MORNING DEVELOPMENTS.
DISTURBANCES PUSHING INTO SOUTHWEST AND WEST CENTRAL MT THIS
MORNING...THEN STRENGTHENING OVER NORTH CENTRAL AND NORTH EAST MT.
PRECIPITABLE WATER AT 0.79 INCHES ON TFX MORNING SOUNDING...SLIGHTLY
LESS THAN YESTERDAYS 0.86 INCHES. LI WAS CALCULATED AT -6 WITH A CAPE
OF 1720 J/KG AND CONVECTIVE TEMP OF 85. SPC KEEPS CWA UNDER SLIGHT
RISK CATEGORY AND THIS LOOKS REASONABLE. BELIEVE CURRENT POPS MAYB E
SLIGHTLY ON THE SHY SIDE...ESPECIALLY NORTH AND WILL RAISE THEM INTO
HIGHER CHANCES AND LIKELY CATEGORIES...MAINLY CENTRAL MT. PATTERN
CHANGES LITTLE ON SATURDAY AS MOIST SOUTHWEST FLOW ALOFT CONTINUES
AND AIRMASS REMAINS UNSTABLE. WILL CONTINUE WITH CHANCE POPS
SATURDAY...ESPECIALLY OVER SOUTHERN PORTION OF CWA. TEMPERATURES
REMAIN STATIC NEXT 48 HOURS.

.EXTENDED...NO SIGNIFICANT CHANGES TO MEDIUM RANGE FORECAST. UPPER
TROF MAINTAINS ITS POSITION WEST OF THE CWA WITH RESULTANT MOIST
SOUTHWEST FLOW ALOFT PERSISTING ACROSS THE AREA. THUS EXPECT
CONVECTIVE ACTIVITY TO BE A POSSIBILITY EACH DAY. MRF AND ECMWF
CONTINUE TO BE IN GENERAL AGREEMENT WITH EACH OTHER. MRF HINTS AT
UPPER TROF FINALLY BEGINNING TO LIFT OUT BY DAY 7. EMANUEL

CCF NUMBERS
GTF TB 084 055 083 053 086 084522
CTB TB 080 053 082 051 084 083{322
HLN TB 087 055 086 054 086 085632
BZN TB 086 054 085 052 086 084532
WEY TB 078 048 078 047 081 085432
DLN TB 083 052 084 050 085 085332
HVR TB 089 058 087 056 088 083422
LWT TB 084 054 084 053 086 084632

MTZ008-011>015-045-047-049>055-131600-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
1100 AM MDT FRI JUL 13 2001

...STRONG THUNDERSTORMS POSSIBLE TODAY AND SATURDAY...

AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS SOUTHWEST MONTANA THIS
AFTERNOON...AND THEN ACROSS CENTRAL MONTANA THIS EVENING. THIS
DISTURBANCE WILL ALLOW FOR THUNDERSTORMS TO DEVELOP BY MID AFTERNOON
FROM NORTHWEST MONTANA EAST OF THE CONTINENTAL DIVIDE INTO
SOUTHWEST MONTANA. THESE THUNDERSTORMS WILL THEN MOVE NORTHEAST...INTO
CENTRAL AND NORTH CENTRAL MONTANA BY THIS EVENING. ANOTHER UPPER
LEVEL DISTURBANCE IS FORECASTED TO TAKE NEARLY THE SAME TRACK ON
SATURDAY.

SOME OF THE STORMS THIS AFTERNOON AND EVENING AND AGAIN SATURDAY
AFTERNOON AND EVENING MAY BECOME SEVERE. THESE SEVERE THUNDERSTORMS
WILL BE CAPABLE OF PRODUCING HAIL TO GOLF-BALL SIZE...WINDS IN
EXCESS OF 60 MPH...AND RAINFALL OF OVER AN INCH IN LESS THAN AN
HOUR.

THEREFORE...IF ANYONE HAS ANY TYPE OF OUTDOOR ACTIVITY PLANNED OVER
THE NEXT TWO DAYS...YOU SHOULD BE PREPARED FOR STRONG THUNDERSTORMS.
LISTEN TO NOAA WEATHER RADIO...OR YOUR FAVORITE SOURCE FOR WEATHER
INFORMATION...FOR ANY WATCHES OR WARNINGS...THAT MAY BE ISSUED.

BLANK