383
FXUS65 KTFX 121743
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1143 AM MDT FRI JUN 12 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- A COLD FRONT WILL BRING SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS TODAY INTO TONIGHT, WITH BRIEF DOWNPOURS,
LOCALIZED GUSTY WINDS, AND OCCASIONAL LIGHTNING BEING THE
PRIMARY HAZARDS.
- COOLER TEMPERATURES AND SOME SHOWERS LINGER INTO SATURDAY AND
SOME WILL SEE FROSTY CONDITIONS SUNDAY MORNING.
- THERE WILL BE A WARMING TREND SUNDAY INTO EARLY NEXT WEEK, WITH
WARM, DRY, AND WINDY CONDITIONS DEVELOPING AHEAD OF A COLD
FRONT ON TUESDAY.
- COOLER CONDITIONS AND PERIODS OF SHOWERS AND THUNDERSTORMS
RETURN FOR THE SECOND HALF OF NEXT WEEK.
DISCUSSION
/ISSUED 552 AM MDT FRI JUN 12 2026/
- METEOROLOGICAL OVERVIEW:
A SHORTWAVE TROUGH AND ATTENDANT COLD FRONT WILL SLIDE SOUTHWARD
AND BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TODAY
INTO TONIGHT. STORM ACTIVITY WILL INITIALLY DEVELOP ALONG THE
CANADIAN BORDER BY THE MID- TO LATE MORNING HOURS BEFORE
PROGRESSING SOUTHWARD THROUGH THE PLAINS IN THE AFTERNOON/EVENING
AND EVENTUALLY INTO THE SOUTHWEST BY TONIGHT. WITH ML CAPE LEVELS
PEAKING AROUND A FEW HUNDRED J/KG, GUSTY WINDS AND BRIEF DOWNPOURS
WILL BE THE PRIMARY HAZARDS TO MONITOR AND THIS WILL BE MOSTLY BE
OVER CENTRAL AND NORTH-CENTRAL MT.
ANOTHER WEAK SHORTWAVE PASSAGE WILL MAINTAIN LINGERING SCATTERED
SHOWERS AND COOLER TEMPERATURES TONIGHT INTO SATURDAY. H700
TEMPERATURES FALLING TO THE -5 TO -8C RANGE MAY BRING SOME WET
HIGH MOUNTAIN SNOW TONIGHT INTO SATURDAY MORNING, ALTHOUGH THIS
COLDER AIR ALOFT WILL NOT BE SUFFICIENTLY PHASED WITH THE MAIN
AREA OF PRECIPITATION FOR ANY APPRECIABLE ACCUMULATION.
AFTER A COOL, FROSTY SUNDAY MORNING, RIDGING ALOFT WILL INITIATE
A WARMING TREND SUNDAY THROUGH TUESDAY. A STRONGER WESTERLY FLOW
DEVELOPS AHEAD OF ANOTHER TROUGH AND COLD FRONT ON TUESDAY, ALONG
WITH A STRIPE OF 40 TO 50 KT H850/H700 WINDS. THIS WILL BRING
WINDY AND DRY CONDITIONS TUESDAY AFTERNOON WHILE TEMPERATURES
SURGE WELL INTO THE 80S. THE COLD FRONT WILL PASS THROUGH SOMETIME
TUESDAY NIGHT INTO WEDNESDAY AND WILL REINTRODUCE SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY AND COOLING TEMPERATURES FOR THE
SECOND HALF OF THE WEEK. - RCG
- FORECAST CONFIDENCE & SCENARIOS:
SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS AND COOLING
TEMPERATURES TODAY THROUGH EARLY SUNDAY...
THE PRIMARY IMPACT FROM TODAY'S GENERAL THUNDERSTORM RISK WILL BE
FOR UNFAVORABLE CONDITIONS FOR OUTDOOR RECREATION. LOCALIZED
DOWNPOURS, GUSTY WINDS, AND OCCASIONAL LIGHTNING WILL BECOME MORE
PREVALENT OVER CENTRAL AND NORTH-CENTRAL MT AS THE DAY PROGRESSES.
THE COLD FRONT WILL ALSO BRING A GUSTY AND CHILLY NORTHERLY WIND
SHIFT WITH MOST PLAINS LOCATIONS SEEING THEIR HIGH TEMPERATURES
PEAK IN MID- MORNING THROUGH THE EARLY AFTERNOON HOURS, EARLIEST
ALONG THE HI-LINE.
THIS ACTIVITY WILL BECOME MORE SCATTERED IN NATURE AS IT MOVES
INTO SOUTHWEST MT LATER THIS EVENING INTO TONIGHT. THEN A
SECONDARY SHORTWAVE WILL MAINTAIN AT LEAST ISOLATED SHOWER
ACTIVITY THROUGH SATURDAY. THE NIGHTS WILL BE ON THE CHILLIER SIDE
AS WELL, ESPECIALLY SUNDAY MORNING WHEN MOST LOWER ELEVATIONS
WILL SEE LOWS IN THE LOWER TO MIDDLE 30S AND SCATTERED AREAS OF
FROST. THE WIND PROTECTED SOUTHWEST VALLEYS WILL SEE THE COLDEST
CONDITIONS.
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 68 43 62 39 / 70 80 20 0
CTB 59 38 61 36 / 90 40 10 0
HLN 73 44 63 40 / 30 60 20 0
BZN 73 41 62 36 / 10 60 40 10
WYS 69 34 62 30 / 10 10 10 0
DLN 75 40 64 36 / 0 20 10 0
HVR 64 40 66 39 / 60 20 10 0
LWT 65 39 57 36 / 40 50 20 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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