210
FXUS65 KTFX 042045
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
245 PM MDT SUN MAY 4 2025
KEY MESSAGES
- ISOLATED THUNDERSTORMS MAINLY BEFORE MIDNIGHT, OTHERWISE
WIDESPREAD LOWER ELEVATION RAIN AND MOUNTAIN SNOW DEVELOP THIS
EVENING.
- RAIN AND SNOW BEGIN TO DIMINISH MONDAY EVENING, BUT WILL LINGER
INTO TUESDAY FOR SOME AREAS OVER OUR FAR EASTERN PORTIONS OF THE
CWA.
- GENERALLY QUIET CONDITIONS EXPECTED FROM WED INTO THE START OF
THE WEEKEND, ALONG WITH A NICE WARMING TREND.
- SOME POTENTIAL FOR ANOTHER WEEKEND WEATHER SYSTEM NEXT WEEKEND,
BUT CONFIDENCE IS QUITE LOW RIGHT NOW FOR THIS OCCURRING.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
RAIN IS AFFECTING AREAS MAINLY WEST OF A LINE FROM AUGUSTA TO
SHELBY THIS AFTERNOON, AS AN UPPER LEVEL DISTURBANCE MOVES
NORTHEASTWARD THROUGH THIS AREA. FURTHER SOUTH,
SHOWERS/THUNDERSTORMS ARE DEVELOPING IN LEMHI COUNTY, ID AND IN
BEAVERHEAD COUNTY, MT. THESE STORMS WILL CONTINUE TO MOVE
NORTHEASTWARD THROUGH THIS EVENING. SOME STORMS COULD PRODUCE
BRIEF HEAVY RAINFALL. OVERALL, THIS AREA OF PRECIPITATION OVER THE
SOUTHWEST WILL BECOME A WIDESPREAD AREA OF LOWER ELEVATION RAIN
AND MOUNTAIN SNOW OVER CENTRAL MT THIS EVENING. THE LATEST NAM
CONTINUES TO INCREASE QPF, WITH AREAS AROUND GREAT FALLS FORECAST
TO RECEIVE OVER 1 INCH OF LIQUID. THIS IS REASONABLE, AND SOME
AREAS WILL GET 1 INCH OF RAIN, IT JUST THE HIGHER AMOUNTS MIGHT
NOT BE OVERLY WIDESPREAD. THAT BEING SAID, MANY AREAS OVER
CENTRAL/NORTH CENTRAL MT ARE LIKELY TO GET BETWEEN 0.50 AND 0.75
INCHES OF LIQUID. THE WINTER WEATHER ADVISORY LOOKS ON TRACK FOR
THE KINGS HILL AREA. TEMPERATURES SHOULD COOL THIS EVENING
ALLOWING THE RAIN TO CHANGE TO SNOW. THE GREATEST IMPACTS WILL BE
FOR ELEVATIONS ABOVE 6000 FEET IN THE KINGS HILL AREA.
FOR MONDAY, EXPECT THE PRECIPITATION TO SLOWLY BEGIN TO DIMINISH
FROM WEST TO EAST. THE PRECIPITATION IS LIKELY TO CONTINUE INTO
TUESDAY MORNING THOUGH OVER THE EASTERN PORTIONS OF THE CWA.
TEMPERATURES WILL BE COOL ON MONDAY, THEN REBOUND A BIT FOR
TUESDAY.
FOR WEDNESDAY THROUGH SATURDAY...A NICE WARMING TREND IS EXPECTED
ACROSS THE CWA. AFTERNOON TEMPERATURES ARE LIKELY TO BE IN THE 70S
WHICH IS A GOOD 10 DEGREES ABOVE NORMAL. A ISOLATED
SHOWER/THUNDERSTORM IS POSSIBLE THURSDAY AND AGAIN ON SATURDAY,
BUT CONFIDENCE IS LOW RIGHT NOW FOR THIS ACTIVITY. FOR NEXT
SUNDAY, THE GFS/EC MODELS ARE PROGGING ANOTHER SPRING STORM TO
AFFECT THE CWA. HOWEVER, HOW MUCH PRECIPITATION IT PRODUCES IS
STILL IN QUESTION.
- FORECAST CONFIDENCE & SCENARIOS:
THE MAIN CONCERN IS RAIN/SNOW TONIGHT. THERE IS NOW AROUND A 90
PERCENT CHANCE FOR 0.50 INCHES OF LIQUID AROUND GREAT FALLS
TONIGHT, AND A 60 PERCENT CHANCE OF 0.50 INCHES AROUND HELENA AND
HAVRE. IN TERMS OF SNOW, THERE IS AN 80 PERCENT CHANCE OF SNOW
ACCUMULATIONS AROUND 6 INCHES IN THE KINGS HILL AREA. ALSO THE
MOUNTAINS AROUND PONY COULD GET 4 TO 6 INCHES OF SNOWFALL AS WELL.
WINDS WILL INCREASE ON THURSDAY A BIT, WITH A 60 PERCENT CHANCE OF
WIND GUSTS NEAR 70 MPH ALONG THE FRONT RANGE OF THE ROCKIES AND A
30 PERCENT CHANCE OF WIND GUSTS NEAR 60 MPH NEAR CUT BANK. IT IS
POSSIBLE THAT HIGH WIND STATEMENTS MIGHT BE NEEDED LATER THIS
WEEK. BRUSDA
AVIATION
04/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS UNTIL THE RAIN MOVES IN
DURING THIS TAF PERIOD. WINDS THROUGH AT LEAST 05/00Z WILL BE GUSTY
AT MOST TERMINALS DUE TO A COLD FRONT THAT IS MOVING THROUGH THE
AREA. THERE IS A 20 - 40% CHANCE FOR THUNDERSTORMS AT THE KEKS,
KBZN, KWYS, AND KHLN TERMINALS BETWEEN 04/21Z AND 05/06Z. ANY
THUNDERSTORM WILL PRODUCE FREQUENT LIGHTNING, SMALL HAIL, GUSTY,
ERRATIC WINDS, AND A BRIEF HEAVY DOWNPOUR. AT ALL TERMINALS EXCEPT
FOR THE KWYS AND KHVR TERMINALS VISIBILITY AND/OR CEILINGS WILL
BE REDUCED TO IFR LEVELS DURING RAINFALL. DURING THE MAJORITY OF
THIS TAF PERIOD THERE WILL BE MOUNTAIN OBSCURATION. DURING THE
FIRST SIX HOURS OF THIS TAF PERIOD THERE WILL BE MOUNTAIN WAVE
TURBULENCE. -IG
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED
REGIONAL AVIATION WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 39 51 31 59 / 100 90 10 0
CTB 38 56 30 61 / 90 50 0 0
HLN 40 51 33 59 / 100 90 20 10
BZN 37 46 30 53 / 90 90 50 20
WYS 35 48 28 56 / 50 70 60 20
DLN 37 47 31 53 / 90 70 30 10
HVR 40 59 31 63 / 90 80 0 0
LWT 35 43 31 53 / 80 100 40 20
TFX WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON MDT
MONDAY FOR LITTLE BELT AND HIGHWOOD MOUNTAINS.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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