350
FXUS65 KTFX 121859
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1259 PM MDT FRI JUN 12 2026
KEY MESSAGES
- SHOWERS AND A FEW THUNDERSTORMS THIS AFTERNOON AND EVENING ALONG
AND BEHIND A COLD FRONT.
- AFTER A SLIGHTLY COOLER SATURDAY, TEMPERATURES TREND WARMER
SUNDAY THROUGH TUESDAY.
- BREEZY TUESDAY AND WEDNESDAY.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
UPPER LEVEL TROUGHING DROPPING SOUTH FROM CANADA IS HELPING PROPEL A
COLD FRONT SOUTHWARD ACROSS THE REGION THIS AFTERNOON. SHOWERS AND A
FEW THUNDERSTORMS WILL CONTINUE ALONG AND BEHIND THE FRONT THROUGH
THE AFTERNOON AND EARLY EVENING. SMALL HAIL AND GUSTY WINDS ARE THE
PRIMARY CONCERN, BUT A ROGUE STRONGER STORM CANNOT BE RULED OUT.
SEE MORE ON THIS IN THE FORECAST CONFIDENCE SECTION. MOST
PRECIPITATION ENDS THIS EVENING AND TONIGHT AHEAD OF THE COLDEST
AIR ALOFT. A FEW FLAKES OF SNOW NEAR THE HIGHER PEAKS IS A
REASONABLE EXPECTATION AT THIS POINT FOR THE OVERNIGHT.
LINGERING COOLER AIR ALOFT SATURDAY WILL COMBINE WITH SUFFICIENT
DAYTIME HEATING TO RESULT IN ADDITIONAL SHOWERS AND PERHAPS ISOLATED
THUNDERSTORMS, MAINLY ACROSS CENTRAL AND SOUTHWEST MONTANA FROM LATE
MORNING THROUGH EARLY EVENING. UPPER LEVEL RIDGING THEN BEGINS TO
BUILD IN, PROMOTING LARGELY CLEAR SKIES AND A WARMING TREND. BEFORE
THE WARMING OCCURS THERE APPEARS TO BE A RISK FOR SOME FROST SUNDAY
MORNING.
THE BUILDING RIDGE LOOKS TO GET FLATTENED TUESDAY INTO WEDNESDAY,
WHICH WILL PROMOTE BREEZY CONDITIONS, PARTICULARLY OVER THE PLAINS.
THE NATURE OF THE FLOW ALOFT LOOKS TO BE A BIT MORE CYCLONIC TUESDAY
NIGHT INTO WEDNESDAY, WHICH WOULD PROMOTE A RETURN OF PRECIPITATION
WHEREVER THE BEST FORCING ENDS UP DEVELOPING.
THEREAFTER A NORTHWESTERLY FLOW ALOFT SLOWLY TRENDS SOUTHWESTERLY,
WHICH WILL GRADUALLY REINTRODUCE AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS TO THE REGION TOWARD NEXT WEEKEND. -AM
- FORECAST CONFIDENCE & SCENARIOS:
STRONGER THUNDERSTORMS THIS AFTERNOON:
SHEAR LOOKS TO GRADUALLY INCREASE ACROSS CENTRAL MONTANA THROUGH THE
AFTERNOON. INSTABILITY INCREASING TOWARD 500 J/KG OR SO COMBINED
WITH THE LOCALLY HIGHER EFFECTIVE SHEAR WILL RESULT IN A NARROW
CORRIDOR FOR A STRONGER THUNDERSTORM OR TWO ACROSS CENTRAL MONTANA,
CAPABLE OF PRODUCING SOME LARGER HAIL (PERHAPS UP TO AN INCH IN
DIAMETER) AND GUSTY WINDS. BOTH SHEAR AND INSTABILITY LOOK TO BE
MAXIMIZED ACROSS CENTRAL MONTANA THIS AFTERNOON, WITH A LESS
FAVORABLE ENVIRONMENT FOR STRONGER THUNDERSTORMS FURTHER NORTH
ACROSS NORTH-CENTRAL MONTANA AS WELL AS FURTHER SOUTH ACROSS
SOUTHWEST MONTANA. -AM
WARM, WINDY, AND, DRY TUESDAY...
WESTERLY WINDS BEGIN TO INCREASE ON TUESDAY IN ADVANCE OF AN
APPROACHING THROUGH AND COLD FRONT. THE NAEFS ANOMALY INDEX ALREADY
HAS H700/H500 WINDS APPROACHING TWO TO THREE STANDARD DEVIATIONS
ABOVE CLIMATOLOGY WITH NBM PROBABILITIES FOR 50 MPH + GUSTS ALREADY
RUNNING ABOVE 50% FOR PORTIONS OF THE FORECAST AREA, INCLUDING THE
ROCKY MOUNTAIN FRONT/PLAINS WEST OF I15 AND AREAS OVER AND NEAR THE
HIGHER TERRAIN OF CENTRAL/SOUTHWEST MT. THE BIGGEST UNCERTAINTY WILL
BE WHEN THE STRONGEST WINDS ALOFT MOVE THROUGH AND WHETHER IT WILL
BE DURING PEAK DIURNAL MIXING OR LATER IN THE EVENING WITH LESS
MOMENTUM TRANSFER.
WITH THIS EVENT BEING FOUR TO FIVE DAYS OUT, THERE'S PLENTY OF TIME
TO IRON OUT ANY CHANGES IN TROUGH/JET STREAK TIMING AND POSITIONING.
AT THIS TIME, THE PRIMARY IMPACT LOOKS BE INCLEMENT OUTDOOR
RECREATION AND DIFFICULT TRAVEL FOR THOSE OPERATING HIGH PROFILE
VEHICLES. THE COMBINATION OF TEMPERATURES WARMING WELL INTO THE 80S
AND RHS FALLING TO NEAR CRITICALLY LOW LEVELS WILL ALSO BE MONITORED
FOR FIRE WEATHER CONCERNS, ALTHOUGH FUELS WILL BE LESS RECEPTIVE
GIVEN RECENT RAINFALL AND GREENUP. - RCG
AVIATION
12/18Z TAF PERIOD
THE COLD FRONT CONTINUE TO PUSH SOUTH ACROSS THE STATE TODAY,
WHICH WILL RESULT IN SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ALONG WITH A NORTH/NORTHWEST WIND SHIFT AT TERMINALS. THE MAIN
HAZARDS WITH THUNDERSTORMS WILL BE GUSTY WINDS AND SMALL HAIL,
WITH BEST CHANCES ALONG AND NORTH OF THE MT HIGHWAY 200 CORRIDOR.
THIS FRONT WILL ALSO BRING MVFR TO IFR CEILINGS AT TIMES,
PARTICULARLY WITH THUNDERSTORMS ALONG THE HI-LINE THIS AFTERNOON
AND LATE TONIGHT INTO SATURDAY MORNING ACROSS OTHER TERMINALS.
-WILSON
PRELIMINARY POINT TEMPS/POPS
GTF 43 62 39 70 / 80 20 0 0
CTB 38 61 36 71 / 40 10 0 0
HLN 44 63 40 73 / 60 20 0 0
BZN 41 62 35 70 / 60 40 10 0
WYS 34 62 30 70 / 10 10 10 0
DLN 41 63 36 70 / 20 10 0 0
HVR 40 66 39 73 / 20 10 0 0
LWT 39 57 36 66 / 50 20 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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