765
FXUS65 KTFX 200425
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
925 PM MST THU DEC 19 2024
AVIATION SECTION UPDATED.
KEY MESSAGES
- DRY WEATHER AND WARMER TEMPERATURES CONTINUE TODAY AND FRIDAY.
- THE FORECAST PERIOD WILL BE WINDY ACROSS THE ROCKY MOUNTAIN
FRONT AND THE NORTH CENTRAL MONTANA PLAINS, MOST NOTABLY ON
SUNDAY AND MONDAY.
- A FEW ROUNDS OF LIGHT MOUNTAIN SNOW AND LOWER ELEVATION RAIN
ARE FORECASTED THIS WEEKEND AND NEXT WEEK.
UPDATE
/ISSUED 814 PM MST THU DEC 19 2024/
SATELLITE IMAGERY THIS EVENING SHOWS MID AND HIGH LEVEL CLOUDS
STREAMING OVER AN UPPER LEVEL RIDGE CENTERED ACROSS THE NORTHERN
ROCKIES. AT THE SURFACE, HIGH PRESSURE AND A COLDER AIRMASS IS
SLIDING SOUTHEAST OUT OF SK WITH THE WESTERN EDGE OF THE COLDER
AIR EXTENDING INTO PORTIONS OF HILL/BLAINE COUNTIES WHERE
TEMPERATURES ARE IN THE SINGLE DIGITS AND LOW TEENS. A BOUNDARY
SITS FROM NEAR CUT BANK SOUTH THROUGH GREAT FALLS AND EAST TO
LEWISTOWN WITH COOLER TEMPERATURES TO THE EAST (IN THE 20S) AND
MILDER TEMPERATURES TO THE WEST (IN THE 30S TO AROUND 40). EXPECT
THE LOCATION OF THIS BOUNDARY TO FLUCTUATE SOME THROUGH THE
OVERNIGHT PERIOD BEFORE RETREATING BACK TO THE NORTHEAST FRIDAY
MORNING AS A SHORTWAVE DISTURBANCE MOVING OVER THE UPPER RIDGE
BRINGS SOME ENHANCEMENT TO SOUTHWESTERLY SURFACE WINDS ALONG THE
EAST SLOPES OF THE ROCKIES. SOME MINOR ADJUSTMENTS WERE MADE TO
TEMPERATURES AND WINDS THROUGH THE OVERNIGHT NIGHT PERIOD IN
ALIGNMENT WITH OBSERVED TRENDS THIS EVENING BUT OVERALL FORECAST
IS IN GOOD SHAPE. HOENISCH
DISCUSSION
/ISSUED 814 PM MST THU DEC 19 2024/
- METEOROLOGICAL OVERVIEW:
THE UPPER-LEVEL RIDGING BUILDING IN TODAY WILL KEEP THE AREA
WARMER AND DRIER, EXCEPT FOR THE HI-LINE REGION. A SURFACE
BOUNDARY DRAPED ACROSS NORTH-CENTRAL MT WILL KEEP THE WARM
TEMPERATURES FROM MIXING IN ALONG THE HI-LINE. A SLIGHT BREAKDOWN
IN THIS RIDGE FRIDAY WILL BRING BREEZY WINDS ACROSS THE PLAINS.
HOWEVER, NEXT CHANCES FOR PRECIPITATION DON'T ARRIVE UNTIL LATE
SATURDAY AS A BROADER UPPER-LEVEL TROUGH MOVES IN. THIS WILL BRING
LIGHT MOUNTAIN SNOW/LOWER ELEVATION RAIN. STRONGER WINDS ALOFT
MOVE IN SUNDAY AND MONDAY MORNING, BRINGING GUSTY CONDITIONS TO
THE ROCKY MOUNTAIN FRONT AND NORTH-CENTRAL MT PLAINS.
NEXT WEEK LOOKS TO REMAIN ACTIVE FOR MAINLY THE MOUNTAINS REGIONS.
A FEW SMALL UPPER-LEVEL WAVES PASS THROUGH THE REGION THROUGHOUT
THE WEEK. THE FIRST ONE ON MONDAY, BRINGING CHANCES FOR LIGHT
PRECIPITATION ALONG THE CONTINENTAL DIVIDE AND SOUTHWEST MT. A
MORE DYNAMIC UPPER-LEVEL TROUGH BRINGS IN MORE WIDESPREAD
PRECIPITATION CHRISTMAS EVE AND EARLY CHRISTMAS MORNING.
TEMPERATURES REMAIN ABOVE AVERAGE THROUGH THE FORECAST PERIOD.
- FORECAST CONFIDENCE & SCENARIOS:
THERE IS HIGH CONFIDENCE FOR DRY WEATHER TODAY AND TOMORROW WITH
BREEZY WINDS ON FRIDAY. GUSTY WINDS SET UP ALONG THE ROCKY
MOUNTAIN FRONT SUNDAY AND MONDAY, WITH A 50% CHANCE AND GREATER
FOR 55 MPH. THE OVERALL SYNOPTIC SET UP DOESN'T LOOK AS IMPRESSIVE
FOR A HIGH WIND EVENT SO NO HIGH WIND PRODUCTS ARE ANTICIPATED AT
THIS TIME. WITH MULTIPLE UPPER-LEVEL WAVES MOVING THROUGH NEXT
WEEK, THERE HAS BEEN GOOD AGREEMENT IN GUIDANCE FOR BREEZY TO
GUSTY WINDS ACROSS THE ROCKY MOUNTAIN FRONT AND NORTH-CENTRAL MT
PLAINS MOST DAYS. WE WILL HAVE TO MONITOR TRENDS FOR A SNEAKY HIGH
WIND SET-UP, BUT I AM NOT ANTICIPATING ANY EVENTS AT THIS TIME.
IN TERMS OF PRECIPITATION FROM LATE SATURDAY TO SUNDAY, HIGHER
END VALUES (75TH PERCENTILE NBM) GIVES 1-4" OF SNOW AT HIGHER
TERRAIN. WITH ONLY MINOR ACCUMULATIONS, ONLY MINOR IMPACTS ARE
ANTICIPATED FOR TRAVEL. ACROSS LOWER ELEVATIONS, THERE'S A 20% FOR
0.05" OF PRECIPITATION ACROSS THE NORTH-CENTRAL MT PLAINS. FOR
RAIN AT LOWER ELEVATIONS ON CHRISTMAS EVE/EARLY CHRISTMAS MORNING,
THERE'S A 20-50% FOR 0.05" OF PRECIPITATION SOUTH OF THE MONTANA
HIGHWAY 200 CORRIDOR. AT HIGHER ELEVATIONS, THERE'S A 30-60%
CHANCE FOR 2" OF SNOW AT PASS LEVEL IN SOUTHWEST MT. -WILSON
AVIATION
20/06Z TAF PERIOD
MID AND HIGH LEVEL CLOUD COVER CONTINUES TO STREAM ACROSS THE
REGION TONIGHT AS AN UPPER LEVEL RIDGE SHIFTS ACROSS THE NORTHERN
ROCKIES WITH DECREASING CLOUDS EXPECTED ON FRIDAY. CANNOT RULE
OUT SOME PATCHY FOG AND/OR LOW CLOUD-DEVELOPMENT NEAR THE KHVR
TERMINAL OVERNIGHT BUT LATEST FORECAST GUIDANCE HAS A LOW (LESS
THAN 20%) PROBABILITY OF THIS. OTHERWISE, VFR CONDITIONS PREVAIL
WITH GENERALLY LIGHT SURFACE WINDS OVERNIGHT GIVING WAY TO BREEZY
WEST TO SOUTHWEST WINDS ON THE PLAINS FRIDAY. HOENISCH
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 30 54 35 55 / 10 0 0 0
CTB 23 49 31 49 / 10 0 0 0
HLN 27 48 28 47 / 0 0 0 0
BZN 22 47 25 49 / 10 0 0 0
WYS 10 37 8 38 / 0 0 0 0
DLN 24 47 25 45 / 0 0 0 0
HVR 3 39 20 44 / 10 10 0 0
LWT 26 53 33 55 / 0 10 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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