Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 020910
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
310 AM MDT WED SEP 2 2015

.DISCUSSION...
WEDNESDAY THROUGH FRIDAY...WEDNESDAY WILL BE THE LAST DAY OF
DRY...BREEZY...AND ABOVE SEASONAL TEMPERATURES FOR A WHILE AS AN
UPPER LEVEL LOW BEGINS TO MOVE INTO THE PACIFIC NORTHWEST AND
SLOWLY IMPACTS THE AREA. PRECIPITATION WILL BEGIN ALONG THE ROCKY
MOUNTAIN FRONT WEDNESDAY EVENING...AND SHOULD BECOME MORE
WIDESPREAD THROUGHOUT THE DAY THURSDAY. RAIN WILL BEGIN AS
SCATTERED SHOWERS WITH POSSIBLE THUNDERSTORMS THURSDAY DURING THE
DAYTIME HOURS AND SHOULD BECOME MORE WIDESPREAD ESPECIALLY OVER
THE ROCKY MOUNTAIN FRONT AND ADJACENT HIGH PLAINS. WINDS WILL
CONTINUE TO REMAIN BREEZY THROUGH THIS TIME PERIOD...ESPECIALLY
FRIDAY. INCREASING CLOUD COVER AND PRECIPITATION SHOULD CREATE
COOLER TEMPERATURES EACH DAY WITH MOST LOCATIONS WELL BELOW
SEASONAL AVERAGES THURSDAY AND FRIDAY. MOISTURE TOTALS FOR THE
FIRST PART OF THE STORM SYSTEM APPEAR TO RANGE IN THE ONE QUARTER
TO ONE INCH RANGE. SUK

FRIDAY NIGHT THROUGH WEDNESDAY...A DEEP UPPER LEVEL LOW
PRESSURE TROF WILL MOVE OVER THE PACIFIC NORTHWEST FRIDAY NIGHT
AND THE ASSOCIATED COLD FRONT WILL MOVE THROUGH CENTRAL MONTANA.
WIDESPREAD PRECIPITATION WILL CONTINUE BEHIND THE FRONT UNDER
MOIST SOUTHWEST FLOW ALOFT. WITH THE COLD AIR ALOFT CROSSING THE
ROCKIES SATURDAY, THE AIR MASS SHOULD BECOME SLIGHTLY UNSTABLE,
ESPECIALLY ACROSS THE SOUTHERN HALF OF THE CWA. THE GFS AND ECMWF
HAVE BECOME MORE SIMILAR...STILL DIFFERENCES IN PLACEMENT BUT THE
TIMING LINES UP BETTER. A CLOSED LOW WILL BE OVER SOUTHERN IDAHO
SATURDAY NIGHT AND MOVE OVER CENTRAL MONTANA BY MID-DAY SUNDAY.
THE AIRMASS WILL BEGIN TO DRY AS THE SYSTEM MOVES EAST SUNDAY
AFTERNOON ALTHOUGH A SHORTWAVE MOVING INTO THE TROF SUNDAY NIGHT
WILL KEEP THE AIRMASS MOIST AND UNSETTLED. THIS SHORTWAVE WILL
MOVE EAST OF THE ZONES BY LATE MONDAY AND THE CHANCE OF
PRECIPITATION WILL DROP MONDAY NIGHT. THE AIR MASS WILL REMAIN
QUITE DRY THROUGH TUESDAY BUT A SHORTWAVE WILL CROSS THE ROCKIES
TUESDAY NIGHT. WITH NORTHWEST FLOW ALOFT, THIS WILL BRING SOME
INCREASED CHANCES OF PRECIPITATION ALTHOUGH COLD FRONT LOOKS QUITE
WEAK. TEMPERATURES WILL BEGIN THE PERIOD WELL BELOW SEASONAL
AVERAGES BEFORE RISING BACK TO NEAR NORMALS SUNDAY. ZELZER

&&

.AVIATION...
UPDATED 0555Z.

VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES. LIGHT WINDS OVERNIGHT
WILL MIX WITH GUSTY WINDS BY 18Z AT MOST SITES BEFORE DECREASING
AROUND SUNSET.  SOME LEE SIDE MOUNTAIN WAVE TURBULENCE WILL AGAIN BE
POSSIBLE AT HIGHER ALTITUDES.

&&

.FIRE WEATHER...
A RED FLAG HAS BEEN ISSUED FOR PARTS OF SOUTHWEST MT (FIRE ZONE
118) FOR NOON TO 9 PM WEDNESDAY.

LITTLE CHANGE IN CONDITIONS EXPECTED FOR WEDNESDAY AS BROAD
SOUTHWEST FLOW ALOFT KEEPS THE REGION WARM AND DRY WITH BREEZY
DAYTIME WINDS. A PACIFIC WEATHER SYSTEM IN WASHINGTON AND BRITISH
COLUMBIAWILL MAKE SLOW EASTWARD PROGRESS. LEADING EDGE OF
SHOWERS FROM THIS SYSTEM MAY REACH THE ROCKY MTN FRONT BY WED EVE,
BUT MAIN MOISTURE PLUME WILL NOT ARRIVE UNTIL THURS. BEST CHANCE
FOR RAIN WILL BE ALONG THE ROCKY MTN FRONT EAST TO THE LITTLE BELT
MTNS WITH WETTING RAINS LOOKING MORE LIKELY IN THAT AREA.
PRECIPITATION WILL BE MORE SPOTTY WITH ONLY LIGHT AMOUNTS (LESS
THAN 0.1 INCH) FOR LOCATIONS EAST AND NORTH OF THE LITTLE BELTS ON
THURS. WARANAUSKAS/SUK

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  82  50  65  46 /   0  20  60  70
CTB  74  45  60  42 /   0  80  90  60
HLN  84  48  68  45 /   0  10  60  70
BZN  87  48  76  45 /   0  10  20  40
WEY  77  40  70  34 /   0  10  10  20
DLN  83  48  73  43 /   0  10  40  40
HVR  85  50  71  49 /   0  20  20  50
LWT  88  48  69  44 /   0  10  20  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
MTZ118.

&&

$$

WEATHER.GOV/GREATFALLS



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