Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 300310
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
910 PM MDT FRI MAY 29 2015

.UPDATE...RELATIVELY QUIET EVENING ACROSS CENTRAL/SOUTHWEST MT.
ONLY AREA OF ACTIVE WEATHER IS BAND OF RAIN SHOWERS AND A FEW
EMBEDDED WEAK THUNDERSTORMS CURRENTLY EXTENDING FROM WESTERN TETON
COUNTY SOUTH TO TOWNSEND (BROADWATER COUNTY). MAIN THREAT FROM
THESE STORMS WILL BE BRIEF DOWNPOURS AND WINDS GUSTING TO 30-40
MPH. THIS AREA HAS BEEN MOVING AT FAIRLY QUICK RATE AND SHOULD
REACH GREAT FALLS AND WHITE SULPHUR SPRINGS BY 10 PM THEN CONTINUE
EASTWARD TONIGHT. THREAT FOR THUNDER WILL DECREASE SO LOOKING AT
JUST RAIN SHOWERS DURING THE OVERNIGHT HOURS. FORECAST STILL ON
TRACK FOR AN ACTIVE THUNDERSTORM DAY TOMORROW ACROSS THE REGION WITH
CHANCE OF STRONGER STORMS ALONG/EAST OF LINE FROM CUT BANK-TO-
GREAT FALLS-TO-BILLINGS.
WARANAUSKAS

&&

.AVIATION...

UPDATED 00Z.

SOME SCATTERED SHOWERS WILL MOVE ACROSS THE AREA THIS EVENING. AHEAD
OF THE NEXT SYSTEM. SUNSET SHOULD LIMIT THE BULK OF THE
SHOWERS...WITH THE ONE EXCEPTION BEING ALONG THE HILINE WHERE A
DISTURBANCE COULD ALLOW FOR ENOUGH OVERNIGHT INSTABILITY TO
MAINTAIN SHOWERS INTO THE MORNING HOURS. CONDITIONS SHOULD START
OUT UNDER VFR FOR SATURDAY MORNING ACROSS THE AREA WITH CUMULUS
DEVELOPMENT BY 18Z AND SCATTERED THUNDERSTORMS DEVELOPING BY 20Z
AND MOVING THROUGH THE AREA THROUGH THE END OF THE TAF PERIOD. SUK

&&

.PREV DISCUSSION...
/ISSUED 600 PM MDT FRI MAY 29 2015/
TONIGHT THROUGH SUNDAY...WEAK INSTABILITY WAS DEVELOPING OVER THE
WESTERN MOUNTAINS FRIDAY AFTERNOON AND STILL EXPECT AT LEAST A FEW
SHOWERS OR THUNDERSTORMS TO DEVELOP LATER THIS AFTERNOON AND
CONTINUE INTO EARLY THIS EVENING IN THE WEST. LATER TONIGHT A
WEAK WEATHER DISTURBANCE ALOFT WILL MOVE THROUGH THE AREA AND
COULD TRIGGER ISOLATED SHOWERS. SATURDAY WILL SEE ANOTHER WEATHER
DISTURBANCE MOVE THROUGH THE AREA DURING THE AFTERNOON.
INSTABILITY AND WIND SHEAR WILL INCREASE AND THERE WILL BE SOME
LIFT FROM THE WEATHER DISTURBANCE AS WELL AS A SURFACE TROUGH.
THERE WILL BE A THREAT OF STRONGER THUNDERSTORMS OVER THE CENTRAL
AND NORTHERN ZONES AND WILL INDICATE THIS IN THE FORECAST. SHOWERS
AND THUNDERSTORMS WILL DIMINISH SATURDAY EVENING AND EXPECT MOSTLY
DRY CONDITIONS AFTER MIDNIGHT AS A WEAK UPPER RIDGE ALOFT MOVES
IN. THEN LOOKING AHEAD TO SUNDAY THE UPPER RIDGE WILL BE OVER
WESTERN MONTANA BUT ANOTHER WEATHER DISTURBANCE ALOFT COMBINED
WITH CONTINUED INSTABILITY WILL GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS OVER CENTRAL AND SOUTHWEST MONTANA BY THE AFTERNOON.
THE UPPER RIDGE WILL RESULT IN WARMER TEMPERATURES SUNDAY WITH
HIGHS IN THE MID TO UPPER 70S FOR MOST LOWER ELEVATIONS. BLANK

SUNDAY NIGHT THROUGH THURSDAY...THE REGION WILL BE UNDERNEATH A
FLAT UPPER LEVEL RIDGE SUNDAY NIGHT THAT WILL GRADUALLY SHARPEN
MONDAY. HOWEVER, MOISTURE AHEAD OF A LOW PRESSURE TROF OVER THE
WEST COAST WILL BE MOVING ACROSS THE ROCKIES AND THE AIRMASS WILL
BECOME UNSTABLE AGAIN BY MONDAY AFTERNOON. A PACIFIC COLD FRONT
ASSOCIATED WITH THE TROF TO THE WEST WILL CROSS THE AREA MONDAY
NIGHT AND BRING COOLER TEMPERATURES TO THE REGION TUESDAY. THE
UPPER LEVEL LOW WILL BROADEN AND BECOME NEARLY STATIONARY OVER THE
WESTERN US. MOISTURE WILL CONTINUE TO MOVE INTO THE REGION AND
HEIGHTS ALOFT WILL CONTINUE TO FALL. THIS WILL KEEP SHOWERS AND
THUNDERSTORMS IN THE FORECAST MOISTURE THROUGH THURSDAY. THE LOW
PRESSURE ALOFT WILL KEEP THE AIRMASS COOL AND TEMPERATURES, AFTER
BEGINNING THE PERIOD SUNDAY NIGHT AND MONDAY WELL ABOVE NORMALS,
WILL TREND LOWER TO NEAR NORMALS BY THURSDAY. ZELZER

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  49  70  51  76 /  20  50  30  20
CTB  43  67  45  74 /  30  50  30  10
HLN  51  74  53  77 /  40  50  40  40
BZN  47  71  50  75 /  20  50  40  30
WEY  39  64  43  69 /  20  40  30  30
DLN  48  71  51  77 /  30  50  40  30
HVR  44  76  47  80 /  10  30  40  20
LWT  46  71  49  73 /  20  60  40  30

&&

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

$$

WEATHER.GOV/GREATFALLS


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