439  
FXUS65 KTFX 072336  
AFDTFX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREAT FALLS MT  
536 PM MDT WED MAY 7 2025  
 
AVIATION SECTION UPDATED.  
   
KEY MESSAGES  
 
- A WARMING TREND CONTINUES THROUGH THE UPCOMING WEEKEND WITH MAINLY  
DRY AND LOCALLY BREEZY CONDITIONS THROUGH THE REST OF THE WORK  
WEEK.  
 
- ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS MAINLY CONFINED TO  
CENTRAL AND SOUTHWEST MONTANA INITIALLY, BECOME MORE  
WIDESPREAD THIS WEEKEND WITH AN INCREASED RISK FOR STRONG  
THUNDERSTORMS BY SUNDAY.  
 
- AN ACTIVE WEATHER PATTERN DEVELOPING NEXT WEEK WILL BRING COOLER  
TEMPERATURES AND OPPORTUNITIES FOR PRECIPITATION.  
 
 
   
DISCUSSION  
 
/ISSUED 219 PM MDT WED MAY 7 2025/  
 
- METEOROLOGICAL OVERVIEW:  
 
BROAD UPPER LEVEL RIDGING REMAINS IN PLACE ACROSS THE NORTHERN TIER  
OF THE US WITH UPPER-LEVEL JET AND MID-LEVEL SHORTWAVE ENERGY  
EJECTING OUT OF A TROUGH IN THE PACIFIC AND LARGELY TRACKING WELL TO  
THE NORTH AND NORTHWEST OF THE REGION THROUGH THE REST OF THE WEEK.  
RISING HEIGHTS BENEATH THE RIDGE WILL SUPPORT A GRADUAL WARMING  
TREND THROUGH THE NEXT SEVERAL DAYS WITH TEMPERATURES PEAKING ON  
SATURDAY BEFORE THE RIDGE MOVES OFF TO THE EAST.  
 
WHILE THE UPPER LEVEL RIDGE WILL MAINTAIN OVERALL DRY CONDITIONS  
INTO THE FIRST PART OF THIS WEEKEND, THERE IS ENOUGH SURFACE  
MOISTURE PRESENT AND SOME INFLUX OF MID LEVEL MOISTURE FOR DAILY  
CUMULUS DEVELOPMENT AND AT LEAST AN ISOLATED CHANCE OF  
SHOWER/THUNDERSTORM DEVELOPMENT EACH AFTERNOON ACROSS PRIMARILY THE  
TERRAIN OF SOUTHWEST AND CENTRAL MT. SHORTWAVE AND UPPER JET ENERGY  
TRACKING ACROSS BC/AB ON THURSDAY WILL SUPPORT A SOMEWHAT BETTER  
CHANCE FOR SHOWER/THUNDERSTORM DEVELOPMENT LATE THURSDAY AS A WEAK  
FRONTAL BOUNDARY AND SURFACE TROUGH SHIFT EAST ACROSS THE AREA.  
BREEZY SOUTHWEST WINDS PERSIST ACROSS MUCH OF THE AREA THROUGH  
THURSDAY AS WELL WITH LIGHTER WINDS FRIDAY AS SURFACE HIGH PRESSURE  
MOVES ACROSS THE CANADIAN PRAIRIES.  
 
A MORE ACTIVE PERIOD OF WEATHER BEGINS THIS WEEKEND AS UPPER LEVEL  
TROUGHING SHIFTS INLAND WITH CONSIDERABLE INSTABILITY DEVELOPING  
UNDER INCREASING SOUTHWEST FLOW ALOFT BY LATE SATURDAY WITH AN  
INITIAL WAVE AND UPPER LEVEL JET ENERGY EJECTING OUT OF THE TROUGH  
ACROSS THE NORTHERN ROCKIES LATE SUNDAY. THIS WILL SUPPORT THE  
POTENTIAL FOR SOME STRONG THUNDERSTORMS LATE SATURDAY WITH A MORE  
WIDESPREAD RISK OF STRONG THUNDERSTORM DEVELOPMENT ON SUNDAY.  
 
- FORECAST CONFIDENCE & SCENARIOS:  
 
SATURDAYS MAX TEMPERATURES ARE LIKELY TO BE THE WARMEST OF THE  
SEASON SO FAR WITH MANY LOWER ELEVATION LOCATIONS REACHING THE MID  
80S. DAILY TEMPERATURE RECORDS FOR SATURDAY ARE STILL A FEW DEGREES  
WARMER THAN CURRENT FORECAST GUIDANCE.  
 
THE COVERAGE AND INTENSITY OF THUNDERSTORMS THIS WEEKEND WILL  
LARGELY DEPEND ON THE DEPTH OF AVAILABLE MOISTURE AND THE TIMING OF  
THE INITIAL WAVE EJECTING OUT OF THE TROUGH, BOTH OF WHICH THERE IS  
STILL SOME UNCERTAINTY (DEWPOINTS IN THE LOW 40S VS AROUND 50F). IN  
ANY CASE, THERE WILL BE AT LEAST SOME RISK FOR BOTH STRONG WINDS AND  
HAIL WITH ANY MORE ORGANIZED THUNDERSTORMS THAT DEVELOP LATER THIS  
WEEKEND, SO THOSE WITH OUTDOOR PLANS SHOULD MONITOR FORECASTS AND  
HAVE A PLAN FOR ALTERNATIVES, ESPECIALLY ON SUNDAY.  
 
MEDIUM RANGE MODELS/ENSEMBLES AGREE TO SHIFT THE LARGER SCALE TROUGH  
ACROSS THE INTERIOR WESTERN US EARLY NEXT WEEK, EMERGING IN THE  
NORTHERN US PLAINS BY WEDNESDAY. THERE IS STILL A FAIR AMOUNT OF  
UNCERTAINTY IN SPECIFIC DETAILS, ESPECIALLY BY TUESDAY AND  
WEDNESDAY, BUT MODERATE CONFIDENCE IN A SHIFT TO COOLER TEMPERATURES  
AND A MORE WIDESPREAD CHANGE FOR PRECIPITATION. HOENISCH  
 
 
   
AVIATION  
 
08/00Z TAF  
 
GUSTY WINDS DIMINISH THIS EVENING, BUT A SHORTWAVE DISTURBANCE  
WILL BRING MORE WINDY CONDITIONS AND ASSOCIATED MOUNTAIN WAVE  
TURBULENCE ALONG THE ROCKY MOUNTAIN FRONT LATER TONIGHT BEFORE  
SPREADING ONTO THE NORTH-CENTRAL MT PLAINS DURING THE DAY ON  
THURSDAY. WINDS GUSTS WILL EXCEED 40 KTS AT TIMES ALONG THE ROCKY  
MOUNTAIN FRONT EASTWARD TOWARDS THE KCTB AREA TONIGHT THROUGH  
THURSDAY MORNING. OTHER TERMINALS OVER THE PLAINS WILL SEE WIND  
GUSTS MOSTLY IN THE 25 TO 35 KT RANGE. SCATTERED CUMULUS WILL  
DISSIPATE TONIGHT WITH THE LOSS OF DAYTIME HEATING, BUT THE  
APPROACHING SHORTWAVE WILL BRING INCREASED MID- AND HIGHER LEVEL  
CLOUDINESS. THERE WILL ALSO BE SCATTERED SHOWERS AND THUNDERSTORMS  
AFTER 08/18Z, MOSTLY FOR AREAS SOUTH OF A KHLN TO KLWT LINE.  
- RCG  
 
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION  
WEATHER AND HAZARD INFORMATION.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
GTF 47 74 42 80 / 0 0 0 0  
CTB 46 68 37 77 / 0 0 0 0  
HLN 48 76 46 81 / 0 20 20 10  
BZN 43 74 41 77 / 10 30 20 10  
WYS 32 67 32 70 / 0 30 20 0  
DLN 42 73 41 77 / 10 30 20 0  
HVR 47 78 39 81 / 0 0 0 0  
LWT 46 71 43 75 / 0 30 30 10  
 
 
   
TFX WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
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