701
FXUS65 KTFX 171851
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
ISSUED BY NATIONAL WEATHER SERVICE MISSOULA MT
1251 PM MDT FRI JUL 17 2026
KEY MESSAGES
- SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL MOVE IN A
SOUTHWEST TO NORTHEAST FASHION LATER THIS AFTERNOON THROUGH THE
EARLY OVERNIGHT HOURS.
- THUNDERSTORM HAZARDS WILL INCLUDE STRONG, GUSTY WINDS, HAIL,
AND TORRENTIAL DOWNPOURS CAPABLE OF LOCALIZED FLOODING.
- WARMER TEMPERATURES AND SLIGHTLY DRIER CONDITIONS MOVE IN FOR
THE WEEKEND, ALTHOUGH THERE WILL STILL BE WIDELY SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY.
DISCUSSION
A SHORTWAVE EMBEDDED WITHIN A SOUTHWESTERLY FLOW ALOFT WILL
INTERACT WITH MONSOON MOISTURE AND AN UNSTABLE PROFILE FOR THE
DEVELOPMENT OF CLUSTERS TO BROKEN LINES OF THUNDERSTORMS MOVING
IN A SOUTHWEST TO NORTHEAST FASHION THIS AFTERNOON INTO TONIGHT.
THE MOST ROBUST CAPE OVER 1,500 J/KG WILL BE SLIGHTLY FARTHER EAST
OF THE 30 +KT BULK SHEAR AREA, BUT THERE WILL CERTAINLY ENOUGH
OVERLAP FOR AT LEAST SCATTERED STRONG TO SEVERE THUNDERSTORMS.
ADDITIONALLY, ANOMALOUSLY HIGH PWATS, GENERALLY BETWEEN AN INCH
AND AN INCH AND A HALF, WILL BE CAPABLE OF PRODUCING BRIEF PERIODS
WITH RAINFALL RATES IN THE HALF TO ONE INCH RANGE AND EVEN HIGHER
IN THE STRONGER CORES. A FLASH FLOOD WATCH WAS SENT OUT AGAIN FOR
THE HORSE GULCH BURN SCAR FOR THIS AFTERNOON AND EVENING. URBAN
AREAS THAT RECEIVE THESE HEAVIER RAINFALL RATES WILL ALSO BE
SUSCEPTIBLE TO LOCALIZED FLOODING, ESPECIALLY OVER CENTRAL AND
NORTH-CENTRAL MT, THOUGH CONFIDENCE WAS NOT QUITE HIGH ENOUGH FOR
ADDITIONAL FLOOD PRODUCTS AT THIS TIME.
SLIGHTLY DRIER AIR MOVES IN FOR THE WEEKEND AS THE FLOW ALOFT
BECOMES MORE WESTERLY AND PUSHES THE RICHEST MOISTURE OFF TO THE
EAST. THERE WILL BE ANOTHER SHORTWAVE THAT PASSES THROUGH AGAIN
ON SATURDAY, BUT IT WILL HAVE LESS CAPE AND MOISTURE TO INTERACT
WITH. THE WIDELY SCATTERED SHOWERS AND STORMS THAT DO DEVELOP
WILL CONTAIN GUSTY, TO LOCALLY STRONG WINDS WITH RH'S DROPPING
BACK DOWN TO THE TEENS SATURDAY AFTERNOON. SIMILAR CONDITIONS
PREVAIL FOR SUNDAY, THOUGH STORM COVERAGE MAY BE EVEN LESS THAN
SATURDAY.
ASIDE FROM A BRIEF COOLDOWN ON MONDAY THANKS TO A PASSING COLD
FRONT, TEMPERATURES WILL BE ON THE RISE THANKS TO HIGH PRESSURE
ALOFT BUILDING OVER THE GREAT BASIN AREA. THE NORTHERN ROCKIES
WILL STILL BE FAR ENOUGH NORTH FOR SHORTWAVES AND MOISTURE TO
COMPROMISE THE HIGH AND BRING AT LEAST WIDELY SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY. - RCG
AVIATION
17/18Z TAF PERIOD
ANOTHER WAVE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO LIFT
NORTH AND EAST ACROSS SOUTHWEST THROUGH NORTH CENTRAL MONTANA THIS
AFTERNOON AND EVENING, WITH THE AREAL COVERAGE BEING MUCH HIGHER
ACROSS LOWER ELEVATIONS THAN THAT OF THURSDAY. THUNDERSTORMS WILL
DEVELOP INITIALLY OVER THE HIGHER TERRAIN OF SOUTHWEST AND WEST
MONTANA BETWEEN 18-21Z THIS AFTERNOON BEFORE MOVING NORTH AND EAST
OVER THE ADJACENT PLAINS AND VALLEYS THROUGH 03-06Z SATURDAY.
PRIMARY THREAT WITH THE STRONGEST STORMS WILL BE GUSTY AND
ERRATIC WINDS; HOWEVER, HAIL CAN'T BE RULED OUT, ESPECIALLY AT
THOSE TERMINALS NEAREST TO SURROUNDING TERRAIN. VFR CONDITIONS
WILL LARGELY PREVAIL, BUT MVFR/LOW-VFR CONDITIONS ARE POSSIBLE
NEAR/BENEATH PRECIPITATION. - MOLDAN
PRELIMINARY POINT TEMPS/POPS
GTF 61 95 61 95 / 90 10 20 0
CTB 60 91 57 87 / 70 10 0 0
HLN 62 93 61 94 / 70 30 30 10
BZN 57 92 57 93 / 70 20 20 10
WYS 48 87 48 86 / 80 20 10 0
DLN 55 89 55 90 / 70 20 10 0
HVR 64 97 63 95 / 70 20 20 0
LWT 56 89 57 90 / 60 20 20 20
TFX WATCHES/WARNINGS/ADVISORIES
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR THE HORSE GULCH
BURN SCAR.
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