432
FXUS65 KBYZ 301920
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
120 PM MDT MON JUN 30 2025
KEY MESSAGES
- TURNING QUITE WARM THIS WEEK WITH MANY LOCATIONS IN THE 90S
TUESDAY THROUGH THURSDAY.
- DRY CONDITIONS TODAY, THEN CHANCE OF THUNDERSTORMS GRADUALLY
INCREASES THROUGH THE MIDDLE OF THE WEEK.
DISCUSSION
TODAY THROUGH TUESDAY NIGHT...
CURRENTLY, RIDGING IS ALLOWING FOR WARMER AND DRYER AIR TO
DOMINATE. HIGHS TODAY ARE EXPECTED TO BE IN THE 80S. FOR TUESDAY,
WEAK ENERGY IN THE LOW LEVELS AND MONSOONAL MOISTURE BEGINNING TO
ADVECT IN FROM THE SOUTHWEST WILL ALLOW FOR AFTERNOON SCATTERED
SHOWERS AND THUNDERSTORMS MAINLY FOR THE MOUNTAINS AND FOOTHILLS.
WITH THE EXPECTATION OF THESE SHOWERS AND THUNDERSTORMS BEING
HIGH BASED, THE MAIN CONCERN WILL BE GUSTY WINDS. THERE IS ALSO A
SMALL CHANCE (10-20%) FOR SHOWERS AND THUNDERSTORMS LATE TUESDAY
AFTERNOON FOR SOUTHEAST MT, ALTHOUGH THERE IS SOME UNCERTAINTY
AMONGST HI-RES MODELS ON WHERE OR IF THESE WILL FORM. THERE IS
DECENT FORCING WITH A WEAK 500 MB JET OVERHEAD, ALONG WITH 30-40
KTS OF SHEAR AND NEAR 1000 J/KG OF MUCAPE FOR SOUTHEAST MT. WITH
THAT, IF ANY THUNDERSTORMS DO FORM, THEY WILL BE STRONG WITH GUSTY
WINDS ASSOCIATED WITH THEM. HIGHS TUESDAY WILL BE IN THE UPPER
80S TO MID 90S. TS
WEDNESDAY THROUGH SUNDAY...
RIDGE WILL BE OVER THE AREA WEDNESDAY HELPING TO BOOST
TEMPERATURES INTO THE MID TO UPPER 90S, AND CAN'T RULE OUT SOME
TRIPLE DIGITS FROM BILLINGS EAST TOWARD MILES CITY. DESPITE THE
RIDGE BEING IN PLACE THERE WILL BE MID LEVEL MOISTURE ADVECTION
FROM THE SOUTHWEST (MONSOON), AND LOW LEVEL MOISTURE ADVECTION
FROM THE SOUTHEAST DUE TO THE THERMAL INDUCED SURFACE TROF TO THE
WEST OF THE AREA RESULTING IN SOUTHEASTERLY LOW LEVEL WINDS. SO,
ITS GOING TO GET HOT AND MUGGY (PWATS ~1.0 INCHES) WITH 20 TO 40
PERCENT CHANCES FOR AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS
ACROSS THE FORECAST AREA WEDNESDAY.
RIDGE AXIS GETS PUSHED EASTWARD A BIT ON THURSDAY ALLOWING HEIGHTS
ALOFT TO DROP SOME. THIS COMBINED WITH MORE AFTERNOON/EVENING
CLOUD COVER WITH LATE DAY CONVECTION WILL DROP TEMPERATURES 5 TO 8
DEGREES FROM WEDNESDAYS HIGHS, A BIT COOLER THAN PREVIOUS
FORECASTS HINTED AT. WITH CONTINUED INFLUX OF LOW TO MID LEVEL
MOISTURE, AND WITH A LACK OF PERSISTENT LOW LEVEL WINDS TO
MOVE/DRY OUT THE PREVIOUS DAYS PRECIPITATION, THE ATMOSPHERE WILL
CONTINUE TO MOISTEN UP (PWATS 1-1.5INCHES) RESULTING IN HIGHER
PRECIPITATION CHANCES (40 TO 60 PERCENT) ALONG WITH HEAVIER
PRECIPITATION AMOUNTS WHERE SHOWERS AND THUNDERSTORMS DO DEVELOP.
A MORE SUBSTANTIAL PACIFIC TROF MOVES IN FROM THE NORTHWEST ON
FRIDAY KNOCKING TEMPERATURES BACK INTO THE LOW TO MID 80S, NEAR
SEASONAL LEVELS IN MANY AREAS. THE COLD FRONT AND COOLER MID LEVEL
AIR WILL INCREASE INSTABILITY AND LIFT OVER THE AREA KEEPING A
GOOD CHANCE (30-60 PERCENT)FOR SHOWERS AND THUNDERSTORMS GOING,
BUT THE NORTHERLY LOW LEVEL FLOW WILL LOWER PWATS COMPARED TO
THURSDAYS VALUES REDUCING THE HEAVIER PRECIPITATION POTENTIAL.
SEASONAL TEMPERATURES AND CONTINUE AFTERNOON AND EVENING
SHOWER AND THUNDERSTORM CHANCES CONTINUE THROUGH THE WEEKEND.
REGARDING THE MID WEEK HEAT: WHILE TEMPERATURES WILL BE WELL INTO
THE 90S WITH EVEN A FEW TRIPLE DIGITS, THE FORECAST TEMPERATURES
ARE NOT UNUSUAL FOR THIS TIME OF YEAR, WHICH IS GENERALLY THE
WARMEST TIME OF YEAR FOR THE NORTHERN ROCKIES. THE LATEST EXTREME
FORECAST INDEX IS NOT SHOWING HIGH TEMPERATURES OVER THE 60TH
PERCENTILE FOR OUR AREA WEDNESDAY WHICH WILL BE THE WARMEST DAY OF
THE FORECAST PERIOD. LOWS WILL GET INTO THE 60-70TH PERCENTILE,
BUT STILL NOT EXTREME (MID 60S TO LOW 70S F). THAT SAID THE
COMBINATION OF HEAT AND HUMIDITY IS STARTING TO REGISTER ON THE
HEATRISK FORECAST FOR WEDNESDAY AND TO A LESSER EXTENT THURSDAY.
IF TRENDS CONTINUE MAY NEED SOME HEAT ADVISORY PRODUCTS FOR AREAS
EAST OF BILLINGS WEDNESDAY. THOSE WITH OUTDOOR ACTIVITIES
(RECREATION OR WORK) SHOULD BE THINKING ABOUT HEAT SAFETY
PRECAUTIONS AS THE WARMEST TEMPERATURES (AND HEAT INDICES) OF THE
SEASON ARRIVE THIS WEEK. CHAMBERS
AVIATION
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. EXPECT SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP MAINLY OVER THE MOUNTAINS AND
FOOTHILLS (KLVM, KSHR) TUESDAY AFTERNOON. ISOLATED SHOWERS AND
THUNDERSTORMS ARE ALSO POSSIBLE (10-20% CHANCE) FOR SOUTHEAST MT
(KBHK) LATE TUESDAY AFTERNOON. TS
PRELIMINARY POINT TEMP/POPS
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 057/093 062/095 063/090 062/082 059/082 057/086 059/089
00/U 11/B 22/T 44/T 44/T 32/T 21/U
LVM 052/093 055/090 056/085 053/080 050/079 050/084 052/086
01/U 23/T 34/T 55/T 54/T 32/T 22/W
HDN 056/095 060/098 063/091 062/083 058/083 055/087 058/091
00/U 11/B 32/T 44/T 44/T 31/U 21/U
MLS 057/096 063/099 068/096 066/087 060/083 058/086 060/090
00/U 10/U 31/B 43/T 43/T 31/U 21/U
4BQ 057/093 062/096 068/093 065/083 060/081 058/084 060/089
00/U 10/U 31/B 53/T 33/T 31/U 21/U
BHK 053/091 060/093 065/094 062/084 057/080 055/083 057/085
00/U 10/U 31/B 43/T 33/T 32/T 21/U
SHR 053/092 057/094 060/088 057/079 052/080 051/084 054/087
01/U 11/B 23/T 55/T 44/T 32/T 21/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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