720
FXUS65 KBYZ 222037
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
237 PM MDT SAT AUG 22 2026
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE WEEKEND. A FEW
STORMS COULD BE STRONG TO SEVERE, ESPECIALLY SUNDAY AFTERNOON
AND EVENING. LOCALIZED HEAVY RAINFALL A THREAT AS WELL.
- DRIER WITH SEASONAL TEMPS NEXT WEEK WITH JUST AN OCCASIONAL
CHANCE OF PRECIPITATION.
DISCUSSION
THROUGH FRIDAY...
AN UPPER LOW MOVING ONSHORE INTO THE PAC NW IS CAUSING THE RIDGE
AXIS OVER THE REGION TO SLOWLY SHIFT EASTWARD, BRINGING AN
INCREASE IN MOISTURE FROM THE SOUTH (PWATS 150-200% OF NORMAL). A
SHORTWAVE MOVING INTO THE REGION FROM THE SOUTHWEST WILL BRING
SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA DURING THE
AFTERNOON AND EVENING, GRADUALLY DECREASING INTO THE LATE EVENING
AND OVERNIGHT. CONVECTION WILL LINGER INTO THE EARLY MORNING HOURS
ACROSS THE FAR EAST, WHERE A LOW LEVEL JET IS EXPECTED TO DEVELOP.
THERE COULD BE A COUPLE STRONG STORMS, WITH STRONG WINDS AND SMALL
HAIL. WITH THE HIGH PWATS, ANY THUNDERSTORM WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL.
THE UPPER LOW PUSHES EAST ALONG THE US/CANADA BORDER SUNDAY INTO
MONDAY, BREAKING DOWN THE UPPER RIDGE. AS THE LOW SLIDES EAST, AN
ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH THE AREA
LATE SUNDAY. AREAS WEST OF BILLINGS COULD SEE A PERIOD OF
ELEVATED FIRE WEATHER CONCERNS ON SUNDAY AS PRE-FRONTAL CONDITIONS
BRING WESTERLY WIND GUSTS OF 15-30 MPH, WITH HUMIDITY DOWN NEAR
20 PERCENT. ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS
(30-60% CHANCE) LOOK TO SPREAD ACROSS THE AREA DURING THE
AFTERNOON AND EVENING AS WELL. A FEW OF THE THUNDERSTORMS COULD BE
SEVERE WITH MODEST INSTABILITY (500-1000 J/KG) AND SHEAR (DEEP
LAYER SHEAR AROUND 30 KTS). THE MAIN THREATS WITH THE
THUNDERSTORMS ARE STRONG WIND GUSTS OF 60+ MPH AND QUARTER SIZE
HAIL. HEAVY RAINFALL IS POSSIBLE WITH THE THUNDERSTORMS AS WELL.
THE SPC CURRENTLY HAS A MARGINAL TO SLIGHT RISK OF SEVERE
THUNDERSTORMS SUNDAY AFTERNOON AND EVENING FOR MOST OF THE AREA.
BEHIND THE COLD FRONT, MONDAY WILL BE MOSTLY DRY AND A FEW DEGREES
COOLER THAN SUNDAY. UPPER LEVEL RIDGING THEN BUILDS IN BY
TUESDAY, BUT WEAK ENERGY AND SLIGHTLY ABOVE NORMAL MOISTURE
(PWATS AROUND 110-140% OF NORMAL) WILL ALLOW FOR PERIODIC CHANCES
FOR SHOWERS AND THUNDERSTORMS TO CONTINUE THROUGH THE END OF THE
WORK WEEK. WHILE UNCERTAINTY EXITS, ANOTHER BREAK DOWN OF THE
UPPER RIDGE COULD OCCUR BY LATE NEXT WEEK.
HIGHS ARE FORECAST TO
RANGE FROM THE 90S MOST PLACES ON SUNDAY, COOLING INTO THE MIDDLE
TO UPPER 80S MONDAY AND TUESDAY. A GRADUAL WARMING TREND IS THEN
FORECAST INTO THE SECOND HALF OF THE WEEK WITH TEMPERATURES IN THE
UPPER 80S TO LOWER 90S. STP
AVIATION
18Z DISCUSSION...
SHOWERS ARE STARTING TO FILL IN FOR AREAS NEAR KBIL/KSHR AND
WESTWARDS. OUT EAST, NEAR KMLS, SE WINDS ARE STARTING TO PICK UP
AS SOME GUSTS TOP 20 KTS. BOTH OF THESE TRENDS WILL CONTINUE OVER
THE COMING HOURS. THERE WILL BE TWO ROUNDS OF SHRA/TS THIS EVENING
AFTER 21Z AND OVERNIGHT THAT MOVE FROM KLVM THROUGH KBIL/KSHR,
ONE IS MORE LIKELY THAN THE OTHER AT EACH SITE AND THUS A TEMPO
AND PROB30 WERE ADDED FOR EACH ROUND RESPECTIVELY. WINDS WITH
THESE STORMS WILL BE ERRATIC WITH GUSTS UP TO 40 KTS POSSIBLE.
RAINFALL RATES MY BE BRIEFLY HEAVY WHICH MAY BRING VIS DOWN TO
MVFR, OTHERWISE ALL SITES SHOULD STAY VFR. ANOTHER ROUND OF TS IS
FORECAST AFTER 18Z SUNDAY. WMR
PRELIMINARY POINT TEMP/POPS
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 067/095 063/088 061/086 061/091 063/093 063/089 061/089
54/T 30/U 00/B 00/B 21/B 20/B 20/B
LVM 056/090 050/087 052/086 052/089 052/089 051/087 050/085
76/T 20/U 01/U 11/B 42/T 21/U 21/U
HDN 064/097 060/089 056/088 056/093 061/094 060/091 058/090
33/T 40/U 00/U 00/U 12/W 20/B 20/B
MLS 068/096 064/087 058/086 057/089 062/093 063/090 060/090
31/U 30/U 00/U 00/U 11/B 20/B 10/B
4BQ 067/095 065/088 059/086 058/089 063/092 063/090 061/090
31/U 30/U 10/U 00/U 11/B 21/B 21/B
BHK 062/094 060/088 054/086 051/088 055/091 057/090 055/090
43/T 30/U 00/U 00/U 11/B 32/W 21/B
SHR 060/092 058/087 055/084 052/088 056/090 056/088 054/088
33/T 30/U 03/T 12/T 21/B 11/B 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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