Hail in Montana, June 24, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
355 AM MDT SUN JUN 24 2007

.DISCUSSION...

TODAY THROUGH TUESDAY...THE SOUTHWEST FLOW ALOFT WILL PERSIST OVER
SOUTHWEST AND NORTH CENTRAL MONTANA THROUGH TONIGHT...AS AN UPPER
LEVEL TROUGH MOVES INTO THE PACIFIC NORTHWEST. A FEW
THUNDERSTORMS DEVELOPED OVER NORTH CENTRAL MONTANA OVERNIGHT...AND
THE AIRMASS REMAINS SLIGHTLY UNSTABLE. THEREFORE...WILL KEEP
MENTION OF ISOLATED THUNDERSTORMS THERE THROUGH THE MORNING. MID
LEVEL MOISTURE IS ALSO MOVING INTO THE AREA FROM THE WEST THIS
MORNING...FOR ISOLATED TO SCATTERED SHOWERS. THE AIRMASS BECOMES
MORE UNSTABLE THIS AFTERNOON AND EVENING...CAUSING SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP. A SURFACE FRONTAL BOUNDARY
WILL ALSO REMAIN OVER SOUTH CENTRAL THROUGH NORTHWEST MONTANA THIS
AFTERNOON AND EVENING...PROVIDING GOOD DIRECTIONAL WIND SHEAR OVER
FERGUS...JUDITH BASIN...AND MEAGHER COUNTIES. THIS MAY CAUSE A FEW
THUNDERSTORMS THERE TO BECOME STRONG WITH LARGE HAIL AND STRONG
WINDS. OVERNIGHT...MOISTURE WILL INCREASE OVER MOST OF THE AREA
FROM THE WEST FOR MORE NUMEROUS SHOWERS WITH CONTINUED SCATTERED
THUNDERSTORMS. THE FRONTAL BOUNDARY WILL ALSO MOVE EAST OUT OF THE
AREA FOR LESS OF A CHANCE FOR STRONG STORMS. THE UPPER TROUGH WILL
THEN MOVE ACROSS MONTANA MONDAY AND MONDAY NIGHT SHOWERS WILL
DECREASE FROM THE WEST. STRONG WESTERLY WINDS WILL ALSO DEVELOP
OVER THE AREA ON MONDAY WITH THE PASSAGE OF THE UPPER TROUGH.
HOWEVER...THESE WINDS SHOULD GENERALLY REMAIN BELOW HIGH WIND
CRITERIA...SO WILL NOT ISSUE A HIGH WIND WATCH AT THIS TIME. WINDS
WILL DECREASE MONDAY NIGHT IN THE WAKE OF THE TROUGH. UPPER LEVEL
RIDGING WILL KEEP THE AREA DRY ON TUESDAY. TEMPERATURES TODAY WILL
BE NEAR NORMAL...THEN THEY WILL COOL BELOW NORMAL ON MONDAY. THE
RIDGING ON TUESDAY WILL CAUSE TEMPERATURES TO WARM BACK TO NEAR
NORMAL.  COULSTON

TUESDAY NIGHT THROUGH FRIDAY NIGHT...MODELS ARE IN GOOD AGREEMENT
BUILDING AN UPPER LEVEL RIDGE OVER MONTANA TUESDAY NIGHT INTO
WEDNESDAY. THIS FEATURE THEN MOVES EAST AT REMAINS ANCHORED OVER
EASTERN MONTANA AND THE DAKOTAS FOR THE REMAINDER OF THE MID
RANGE PERIOD. AN UPPER LEVEL TROUGH WILL SET UP OVER THE EASTERN
PACIFIC AND ATTEMPTS TO MOVE INLAND BY LATE IN THE PERIOD...BUT
WILL MAKE LITTLE HEADWAY AS THE UPPER RIDGE STANDS FIRM. SCENARIO
PUTS MY ENTIRE FORECAST AREA UNDER AN UNSTABLE SOUTHWEST FLOW
ALOFT ONCE AGAIN. THIS WILL BRING AT LEAST A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE AREA...AND TEMPERATURES WILL
WARM WELL ABOVE SEASONAL NORMALS. MPJ

SATURDAY AND SUNDAY...A LOW PRESSURE TROUGH IS EXPECTED TO BE
MOVING ONTO THE PACIFIC NORTHWEST COAST DURING THIS PERIOD. A
CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE CWA AS PACIFIC
MOISTURE IN A SOUTHWEST FLOW ALOFT BEGINS TO MOVE EASTWARD.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL. SAUCIER

&&

.AVIATION...
UPDATED 0500Z.
AN UNSTABLE SOUTHWESTERLY FLOW ALOFT WILL RESIDE OVER THE REGION
THROUGH TONIGHT. EXPECT SCATTERED THUNDERSTORMS...WITH THE BEST
CHANCE FOR THUNDERSTORMS OVER NORTH CENTRAL MONTANA TO CONTINUE
UNTIL ABOUT 11Z SUNDAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED
OVER THE REGION TONIGHT THROUGH SUNDAY. A FEW AFTERNOON
THUNDERSTORMS WILL ONCE AGAIN DEVELOP AFTER 21Z
SUNDAY...ESPECIALLY FOR LOCATIONS WEST OF A LINE FROM HAVRE TO
BOZEMAN. EXPECT A MORE WIDESPREAD PRECIPITATION EVENT FROM 0Z
MONDAY UNTIL 06Z MONDAY WEST AND NORTH OF GREAT FALLS...WITH
POSSIBLE IFR CONDITIONS POSSIBLE. BRUSDA

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  77  51  65  42 /  20  60  40  10
CTB  75  48  63  44 /  20  70  60  20
HLN  82  53  69  43 /  20  60  40  10
BZN  84  49  73  38 /  20  30  20  10
WEY  77  41  69  37 /  10  10   0   0
DLN  81  46  70  37 /  20  20  10  10
HVR  82  54  70  47 /  20  60  60  20
LWT  78  52  66  43 /  20  40  20  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...COULSTON
LONG TERM...MPJ/SAUCIER
AVIATION...BRUSDA

WEATHER.GOV/GREATFALLS