Area Forecast Discussion
Issued by NWS Great Falls, MT

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902
FXUS65 KTFX 131632
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
932 AM MST SAT FEB 13 2016

.DISCUSSION...

TODAY...WARMING TEMPS AND INCREASING WIND HAVE REDUCED REDUCED
THE FOG ACROSS THE NORTHEASTERN ZONES AND THE FREEZING FOG
ADVISORY HAS BEEN CANCELLED. FRESHENED FIRST PERIOD POPS, WX, AND
QPF. ZELZER


&&

.AVIATION...
UPDATED 1155Z.
A DISTURBANCE ALOFT AND ASSOCIATED SURFACE COLD FRONT WILL MOVE
ACROSS THE AREA THIS MORNING. SCATTERED RAIN AND/OR SNOW SHOWERS
WILL ACCOMPANY THE FRONT. PRECIPITATION SHOULD END BY 19Z. WINDS
WILL INCREASE AFTER 18Z AND BECOME GUSTY. STRONGEST WINDS WILL BE
ALONG THE ROCKY MOUNTAIN FRONT AND ADJACENT PLAINS. AREAS OF DENSE
FOG ACROSS THE HI-LINE WILL DISSIPATE BY 18Z. VFR CONDITIONS PREVAIL
WITH MVFR CONDITIONS IN THE VICINITY OF SHOWERS AND FOG.

&&

.PREV DISCUSSION...
/ISSUED 455 AM MST SAT FEB 13 2016/

TODAY THROUGH MONDAY...A PACIFIC FRONT PRESENTLY MOVING THROUGH
NORTHWEST MONTANA WILL ADVANCE ACROSS THE FORECAST AREA THIS
MORNING. RADAR REFLECTIVITY AND SURFACE OBSERVATIONS INDICATE THAT
PRECIPITATION ASSOCIATED WITH THIS FRONT IS BEING SUPPRESSED IN
DOWNSLOPE FLOW EAST OF THE CONTINENTAL DIVIDE. HOWEVER, SHORT-TERM
GUIDANCE SUGGESTS THAT LIGHT RAIN AND MOUNTAIN SNOW WILL DEVELOP
ACROSS MUCH OF THE SOUTHWEST LATER TODAY AS THE UPPER TROUGH AXIS
CROSSES THE REGION. PRESSURE RISES BEHIND THE FRONT WILL HELP MIX
DOWN A PERIOD OF HIGHER WINDS SATURDAY AFTERNOON. WIND GUSTS ARE
EXPECTED NEAR 60 MPH ALONG THE ROCKY MOUNTAIN FRONT AND UP TO 40 MPH
ACROSS THE CENTRAL PLAINS. FREEZING FOG IS OBSERVED THIS MORNING
ACROSS THE HI-LINE COUNTIES WHERE TEMPERATURES ARE IN THE 20S UNDER
A TEMPERATURE INVERSION. THIS INVERSION WILL MIX OUT AND ERODE THE
FOG FROM WEST TO EAST WITH THE PASSING FRONT. GIVEN THE MARGINAL
POPS OVER THIS AREA, WILL HAVE TO MONITOR FOR POSSIBLE LIGHT
FREEZING RAIN UNTIL THE COLDER AIR MIXES OUT. PRECIPITATION AND
WINDS TAPER SATURDAY NIGHT AS THE SYSTEM EXITS TO THE EAST.

RAIN AND MOUNTAIN SNOW DEVELOPS AGAIN EARLY SUNDAY AND CONTINUES
THROUGH MONDAY MORNING OVER THE NORTHERN ROCKIES AND ACROSS SOUTHWEST
MT. UP TO AROUND 2 INCHES OF SNOW WILL BE POSSIBLE DURING THIS
PERIOD OVER ROCKY MOUNTAIN PASSES, WITH 3 TO 5 INCHES POSSIBLE ON
HIGHER PEAKS OF CENTRAL AND SOUTHWEST MT. PRECIPITATION FINALLY
TAPERS LATE MONDAY WITH UPPER LEVEL RIDGING. THE NORTHWESTERLY
FLOW WILL SUPPORT CONTINUED MILD AND WINDY CONDITIONS AS WE REMAIN
JUST ON THE WARM/EQUATORWARD SIDE OF THE UPPER LEVEL JET. PN

MONDAY NIGHT THROUGH SATURDAY...MEDIUM RANGE PERIOD BEGINS ON A
WINDY NOTE AS A LEE SIDE TROF WILL ENHANCE A TIGHT SURFACE GRADIENT
RESULTING IN THE POSSIBILITY OF STRONG WINDS ACROSS THE NORTHERN
PLAINS. 00Z MODEL DATA APPEARS TO BE BACKING OFF A BIT ON THE WIND
SPEEDS FROM EARLIER RUNS BUT ENOUGH CONFIDENCE REMAINS THAT GUSTY
WINDS WILL CONTINUE MONDAY NIGHT THROUGH THE DAY TUESDAY. ISOLATED
SHOWERS ARE ALSO POSSIBLE TUESDAY AS SHORT WAVE ENERGY BRINGS A
PLUME OF PACIFIC MOISTURE THROUGH THE AREA. BY WEDNESDAY, THE UPPER
RIDGE REBUILDS OVER THE AREA WITH ITS AXIS ALONG THE CONTINENTAL
DIVIDE, RESULTING IN DRY AND MILD CONDITIONS. THURSDAY FINDS THE
RIDGE MOVING EAST AS AN UPPER TROF PUSHES INTO THE AREA. THE GFS IS
FASTER WITH THIS FEATURE AND HAS IT OVER NORTHEAST MONTANA BY
LATE AFTERNOON WHILE THE ECMWF KEEPS THE TROF BACK OVER WESTERN
MONTANA. SCATTERED SHOWERS THURSDAY WILL LIKELY OCCUR OVER THE
WESTERN MOUNTAINS AND OVER SOUTHWEST MONTANA. A TIGHT SURFACE
GRADIENT THURSDAY WILL ALLOW WINDS TO INCREASE AND BECOME GUSTY AGAIN
OVER THE NORTHERN PLAINS. THE UPPER RIDGE STRONGLY AMPLIFIES OVER
THE AREA FRIDAY BUT IS SHORT-LIVED AS ANOTHER SHORT WAVE APPROACHES
FROM THE WEST FRIDAY NIGHT INTO EARLY SATURDAY. TEMPERATURES WILL
CONTINUE ABOVE SEASONAL AVERAGES.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  34  52  39 /  10  10  20  20
CTB  48  32  50  37 /  10  10  10  20
HLN  44  32  46  36 /  40  20  20  30
BZN  39  25  41  31 /  50  20  50  40
WEY  33  21  32  26 /  60  60  60  60
DLN  39  29  42  34 /  40  20  30  20
HVR  49  30  50  32 /  20  10  10  20
LWT  43  30  44  33 /  50  10  30  30

&&

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

$$

WEATHER.GOV/GREATFALLS



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