Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 041745
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1145 AM MDT MON MAY 4 2015

UPDATED AVIATION SECTION

.DISCUSSION...
UPDATE FORTHCOMING. HAVE MADE MINOR COSMETIC CHANGES TO CURRENT
FORECAST. ONE MORE DAY OF DRY AND STABLE CONDITIONS. PATTERN CHANGE
STILL ON TRACK FOR TUESDAY.

&&

.AVIATION...
UPDATED 1745Z.
HIGH PRESSURE ALOFT CONTINUES TO PROVIDE DRY AND
STABLE CONDITIONS. INCREASING SOUTHWEST FLOW ALOFT IS BRINGING SOME
MOISTURE TO SOUTHWEST MONTANA WHERE THE AIRMASS WILL DESTABILIZE A
BIT DURING THE AFTERNOON. ISOLATED THUNDERSTORMS ARE POSSIBLE,
MAINLY OVER SOUTHWEST MONTANA AFTER 21Z. CONVECTIVE ACTIVITY SHOULD
END BY 06Z. VFR CONDITIONS PREVAIL WITH MVFR CONDITIONS POSSIBLE IN
THE VICINITY OF THUNDERSTORMS ALONG WITH GUSTY ERRATIC WINDS.

&&

.PREV DISCUSSION...ISSUED 340 AM MDT MON MAY 4 2015

TODAY THRU WEDNESDAY...TODAY WILL BE THE LAST FAIRLY QUIET WEATHER
DAY BEFORE THINGS START TO BECOME MORE ACTIVE AND UNSETTLED ACROSS
THE REGION. THE FLOW ALOFT WILL SHIFT MORE SOUTHWESTERLY THIS
AFTERNOON...ALLOWING FOR A RETURN FOR MORE WIDESPREAD 70 DEGREE
TEMPERATURES ACROSS THE REGION. A FEW LIGHT SHOWERS WILL MOVE
EASTWARD ACROSS SOUTHWEST MT THIS MORNING...AND THESE SHOWERS
COULD TURN INTO ISOLATED THUNDERSTORMS THIS AFTERNOON OVER THE
SOUTHWEST...POSSIBLY GOING AS FAR NORTH AS CENTRAL MT BY EVENING.
FOR TUESDAY...IT WILL REMAIN MILD AHEAD OF A PACIFIC COOL FRONT.
THE COOL FRONT SHOULD MOVE EASTWARD THRU THE REGION DURING THE
LATE AFTERNOON/EVENING HOURS. THE AIRMASS WILL BE UNSTABLE ENOUGH
FOR WIDESPREAD SHOWERS/THUNDERSTORMS TO DEVELOP OVER CENTRAL/NORTH
CENTRAL MT. MOST STORMS SHOULD REMAIN BELOW SEVERE CRITERIA...BUT
A STRONG STORM OR TOO IS POSSIBLE. TEMPERATURES COOL DOWN FOR
WEDNESDAY...WITH SCATTERED SHOWERS CONTINUING MAINLY OVER
SOUTHWEST MT. TOTAL PRECIPITATION AMOUNTS FOR TODAY THRU WEDNESDAY
WILL GENERALLY BE LESS THAN 0.15 INCHES...BUT A HEAVIER
RAIN SHOWER/THUNDERSTORM COULD BOOST ISOLATED LOCATIONS TO AROUND
0.40 INCHES. BRUSDA

WEDNESDAY NIGHT THRU MONDAY...AN UPPER LEVEL TROF OF LOW PRESSURE
WILL GENERALLY RESIDE OVER THE CENTRAL ROCKY MOUNTAIN STATES
THROUGH MUCH OF THIS PERIOD. THIS WILL ALLOW FOR SCATTERED SHOWERS
TO CONTINUE OVER MUCH OF SOUTHWEST MONTANA THRU THE ENTIRE
EXTENDED. FURTHER NORTH...THE CHANCES FOR SHOWERS LOOK TO BE A BIT
MORE LIMITED...BUT AN ISOLATED PASSING SHOWER CAN NOT BE RULED
OUT. ANOTHER CONCERN THOUGH FOR THE EXTENDED WILL BE OVERNIGHT LOW
TEMPERATURES. WITH COOL CANADIAN AIR RESIDING OVER THE
REGION...NIGHT TIME LOWS WILL BE NEAR 30 DEGREES AT TIMES AT LOWER
ELEVATIONS AND IN THE 20S IN THE MOUNTAINS. THESE TEMPERATURES
COULD CAUSE MINOR PROBLEMS FOR THOSE WHO HAVE SPRING TIME
VEGETATION OUTSIDE ALREADY. ADDITIONALLY...SNOW WILL MIX IN AT
TIMES...BUT ANY SNOW ACCUMULATIONS SHOULD BE CONFINED TO THE
MOUNTAINS. TOTAL PRECIPITATION AMOUNTS WILL GENERALLY BE 0.10 TO
0.20 INCHES DURING THIS PERIOD...BUT SOME ISOLATED HEAVIER POCKETS
OF PRECIP WILL BE POSSIBLE...ESPECIALLY IN THE MOUNTAINS. BRUSDA

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  76  46  75  45 /  10  10  30  60
CTB  73  39  70  36 /  10  10  30  40
HLN  77  44  76  42 /  10  10  30  60
BZN  73  42  73  42 /  20  10  40  60
WEY  67  33  66  32 /  30  20  40  40
DLN  73  44  71  42 /  20  20  40  40
HVR  77  40  80  44 /  10  10  20  60
LWT  74  46  76  45 /  10  20  30  60

&&

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

&&

$$

WEATHER.GOV/GREATFALLS


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