889
FXUS65 KTFX 281738
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1138 AM MDT TUE APR 28 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- TODAY THROUGH WEDNESDAY THERE WILL BE ISOLATED SNOW/RAIN
SHOWERS IN THE AFTERNOON AND EVENING.
- THURSDAY AND FRIDAY IT WILL BE WARM AND DRY WITH PRECIPITATION
RETURNING FOR THE WEEKEND.
DISCUSSION
/ISSUED 507 AM MDT TUE APR 28 2026/
- METEOROLOGICAL OVERVIEW:
TODAY NORTHWEST FLOW ALOFT REMAINS OVER NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. THIS WILL ALLOW TEMPERATURES TO WARM UP TO
NEAR SEASONAL AVERAGES WITH MOUNTAIN SNOW SHOWERS AND ISOLATED
SNOW/RAIN SHOWERS IN LOWER-ELEVATION AREAS. WARMING TEMPERATURES
WILL ALLOW INSTABILITY TO BUILD THIS AFTERNOON. THIS WILL LEAD TO A
FEW RUMBLES OF THUNDER TUESDAY AFTERNOON IN CENTRAL MONTANA. ON
WEDNESDAY AN UPPER-LEVEL RIDGE BEGINS TO APPROACH MONTANA WITH
NORTHWEST FLOW ALOFT OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA. THIS WILL KEEP TEMPERATURES AROUND SEASONAL AVERAGES. THERE
WILL BE ANOTHER DAY OF MOUNTAIN SHOWERS WITH ISOLATED LOWER-
ELEVATIONS SEEING RAIN/SNOW SHOWERS. WARMING TEMPERATURES WILL ALLOW
INSTABILITY TO BUILD THIS AFTERNOON. THIS WILL LEAD TO A FEW RUMBLES
OF THUNDER TUESDAY AFTERNOON IN CENTRAL MONTANA.
THURSDAY THROUGH FRIDAY AN UPPER-LEVEL RIDGE GRADUALLY MOVES OVER
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL ALLOW
TEMPERATURES TO GRADUALLY WARM UP WITH MOSTLY DRY WEATHER. SATURDAY
THROUGH SUNDAY AN UPPER-LEVEL TROUGH BEGINS TO MOVE OVER CALIFORNIA
WITH NORTHWEST FLOW OVER MONTANA. THIS WILL BRING SLIGHTLY COOLER
TEMPERATURES AND MORE WIDESPREAD PRECIPITATION TO NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. ON MONDAY AN UPPER-LEVEL RIDGE
BEGINS TO BUILD IN OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA. THIS WILL ALLOW TEMPERATURES TO WARM UP WITH MOSTLY DRY
WEATHER. -IG
- FORECAST CONFIDENCE & SCENARIOS:
TODAY THERE IS A 15 - 20% FOR THUNDER IN CENTRAL MONTANA. ON
WEDNESDAY THERE IS A 15 - 25% CHANCE FOR THUNDER IN CENTRAL AND
SOUTHWESTERN MONTANA. DETERMINISTIC MODELS AND ENSEMBLE CLUSTERS ARE
IN GOOD AGREEMENT THAT THIS WEEKEND THERE WILL BE AN UPPER-LEVEL LOW
OFF THE COAST OF CALIFORNIA WITH NORTHWEST FLOW OVER MONTANA.
HOWEVER, THERE REMAINS SOME UNCERTAINTY WITH THE OVER ALL TRACK OF
THE UPPER-LEVEL PATTERN. THIS LEADS TO UNCERTAINTY IN HOW MUCH
COOLING WILL OCCUR AND HOW MUCH/WIDESPREAD PRECIPITATION OCCURS/IS
THIS WEEKEND. -IG
AVIATION
28/18Z TAF PERIOD
AN UNSTABLE NORTHWESTERLY FLOW ALOFT WILL RESIDE OVER THE CWA
THROUGH THE PERIOD. WITH COLD AIR ALOFT, THERE WILL BE A CHANCE
FOR SCATTERED RAIN OR SNOW SHOWERS ACROSS THE CWA THROUGH THE
AFTERNOON AND EVENING HOURS. SINCE SHOWER ACTIVITY IS EXPECTED TO
BE A BIT SCATTERED AND BRIEF, I OPTED FOR PROB30 GROUPS IN THIS
ROUND OF TAFS. LIGHTNING IS POSSIBLE THIS AFTERNOON BUT WITH THE
PROBABILITY BEING LESS THAN 15%, THE MENTION OF TSRA WAS LEFT OUT.
OVERNIGHT THERE IS THE POTENTIAL FOR FOG DEVELOPING IN LOCATIONS
THAT RECEIVED RAIN EARLIER IN THE DAY. BECAUSE CONFIDENCE IN WHERE
THE SHOWERS WILL BE IS LOW, CONFIDENCE IN FOG DEVELOPMENT REMAINS
LOW AT THIS TIME. SO FOR NOW IT WAS LEFT OUT OF THE TAF.
MOUNTAIN OBSCURATION WILL REMAIN A CONCERN THROUGH THE AFTERNOON
AND EVENING HOURS. -THOR
PRELIMINARY POINT TEMPS/POPS
GTF 55 32 56 31 / 30 20 20 0
CTB 54 30 56 29 / 20 20 20 0
HLN 55 33 56 31 / 40 30 40 10
BZN 53 29 55 27 / 40 40 50 20
WYS 45 22 47 20 / 40 30 70 30
DLN 53 31 55 30 / 20 20 50 20
HVR 57 29 58 29 / 10 10 20 0
LWT 52 28 52 27 / 50 40 30 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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