137
FXUS65 KBYZ 051926
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
126 PM MDT SAT JUL 5 2025
KEY MESSAGES
- COOLER TEMPERATURES THROUGH SUNDAY.
- SCATTERED STRONG TO SEVERE THUNDERSTORMS POSSIBLE TODAY, STARTING
EARLIER IN THE DAY THAN USUAL. BE WEATHER AWARE AND HAVE PLANS
TO SEEK SHELTER IF STORMS APPROACH.
- HOT AND MAINLY DRY NEXT WEEK, 90S TO NEAR 100 DEGREES TUESDAY
AND WEDNESDAY.
DISCUSSION
THROUGH MONDAY NIGHT...
THE STAGE REMAINS SET FOR A COUPLE PERIODS OF STRONG TO SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING OVER THE AREA AS A
PACIFIC TROUGH MOVES THROUGH THE REGION. A BROAD AREA OF MUCAPE IN
THE 1500-2500 J/KG IS EXPECTED TO BE OVER A LARGE PORTION OF THE
AREA BY THE AFTERNOON, WITH BULK SHEAR OF 40 TO 55KTS CO-LOCATED.
STORMS WILL GET GOING EARLIER THAN NORMAL, EARLY AFTERNOON IN THE
WEST, SPREADING EAST THROUGH THE AFTERNOON AND EVENING HOURS. 1 TO
2 INCH DIAMETER HAIL AND GUSTS TO 70 MPH SEEM REASONABLE WITH
STRONGER STORMS TODAY, AND AN ISOLATED TORNADO CAN'T BE RULED OUT
WITH ELEVATED VALUES FOR LOW LEVEL EHI/VGP PARAMETERS ESPECIALLY
IN THE EARLY PART OF THE AFTERNOON. LOCALLY HEAVY RAINFALL IS
POSSIBLE AS WELL WITH PRECIPITABLE WATER VALUES IN EXCESS OF AN
INCH, AND WPC HAS A MARGINAL RISK FOR EXCESSIVE RAINFALL OVER THE
AREA.
A COLD FRONT ASSOCIATED WITH THE TROUGH WILL BRING A SECOND
ROUND OF THUNDERSTORMS LATE THIS AFTERNOON AND EVENING BEHIND THE
INITIAL ACTIVITY. THIS ACTIVITY SHOULD BE WEAKER THAN THE FIRST
WITH THE ATMOSPHERE HAVING ALREADY BEEN WORKED ON BY THE FIRST SET
OF STORMS. THAT SAID THERE COULD STILL BE A FEW STRONG TO
MARGINALLY SEVERE STORMS WITH THIS ROUND AS WELL. CONVECTION WILL
SHIFT OUT OF THE AREA TO THE EAST BY LATE EVENING, WITH QUIETER
WEATHER EXPECTED OVERNIGHT INTO SUNDAY. PATCHY FOG IS POSSIBLE
OVER THE AREA LATE TONIGHT AS SKIES CLEAR.
SEASONAL TEMPERATURES AND MAINLY DRY CONDITIONS WILL PREVAIL FOR
SUNDAY. HIGHS IN THE 75 TO 85 DEGREE RANGE CAN BE EXPECTED. A FEW
ISOLATED SHOWERS OR RUMBLES OF THUNDER CAN'T BE RULED OUT NEAR THE
HIGHER TERRAIN, BUT THE CHANCE REMAINS LOW (15% OR LESS). A
DISTURBANCE CROSSING NEAR THE CANADIAN BORDER WILL BRING LOW
CHANCES (20%) FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY NIGHT INTO
MONDAY MORNING OVER EASTERN AREAS. HIGH PRESSURE BUILDING OVER
THE REGION WILL DRIER AND WARMER CONDITIONS FOR THE SECOND HALF OF
MONDAY, WITH HIGHS IN THE 80S MOST PLACES. STP
TUESDAY THROUGH SUNDAY...
BY TUESDAY, A FAIRLY STRONG RIDGE WILL HAVE BUILT BACK INTO MUCH
OF THE NORTHERN ROCKIES REGION WITH CALMER WEATHER. HIGH TEMPS
ACROSS THE FORECAST AREA MIDWEEK WIL BE BACK IN THE MID TO UPPER
90S FOR A MAJORITY OF THE AREA. WEDNESDAY WILL LIKELY BE THE
WARMEST DAY WITH THERE BEING GOOD CONSENSUS IN THE LATEST NBM RUN.
EVEN THE MORE CONSERVATIVE ESTIMATES (NBM 25%) SHOW PLACES LIKE
BILLINGS AND MILES CITY, APPROACHING OR ECLIPSING 100F ON
WEDNESDAY.
RH VALUES ARE FORECAST TO DROP INTO THE MID TEENS FOR PARTS OF THE
AREA DURING THIS TIME AS WELL. THE GOOD NEWS FOR FIRE CONCERNS,
HOWEVER, IS THAT WINDS WILL REMAIN LIGHT (GUSTS UNDER 15-20KTS)
AND THAT MUCH OF THE AREA IS STILL GREEN AND WITH NO REPORTS OF
ANY VEGITATION CURING YET.
ON THURSDAY, THE RIDGE COULD BREAK DOWN SLIGHTLY. BOTH THE GFS
AND ECMWF SHOW A SHORTWAVE TROUGH MOVE THROUGH THE AREA AT SOME
POINT DURING THE DAY THURSDAY. WHILE THE ECMWF DETERMINISTIC
SOLUTION IS STRONGER THAN THAT OF THE GFS, THERE IS STILL A 30-40%
CHANCE OF SCATTERED SHOWERS ACROSS THE CWA.
THE WARMER CONDITIONS SHOULD CONTINUE INTO THE WEEKEND BUT THERE
DOES APPEAR TO BE A GROWING CONSENSUS IN ANOTHER PACIFIC TROUGH
MOVING THROUGH LATER NEXT WEEKEND. THE CLUSTERS DO SHOW A LOT OF
DISAGREEMENT STILL AND THUS THIS WIL HAVE TO BE MONITORED AS THE
WEEK PROGRESSES. WMR
AVIATION
18Z DISCUSSION...
TS FORMING OVER THE MOUNTAINS NOW AND PUSH EAST THIS AFTERNOON.
SOME STORMS ARE EXPECTED TO BECOME SEVERE WITH WINDS POTENTIALLY
GUSTING TO 60KTS AND LARGE GR. ALL SITES HAVE THE POTENTIAL FOR
SEVERE WEATHER TODAY, HOWEVER, KMLS/KBHK/KBIL HAVE THE GREATEST
POTENTIAL. MOUNTAINS WILL BE PARTIALLY OBSCURED IN THESE STORMS.
EXPECT PREVAILING WINDS TO SHIFT OUT OF THE NW AFTER 00Z. WMR
PRELIMINARY POINT TEMP/POPS
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 054/083 059/087 060/097 065/098 063/085 056/079 055/089
50/U 10/U 00/U 00/U 11/B 42/T 11/U
LVM 044/081 049/086 052/092 056/092 054/083 049/080 049/088
30/U 00/U 00/U 00/U 12/T 32/W 11/U
HDN 054/083 056/089 058/098 061/099 061/086 054/079 052/090
60/U 10/U 00/U 00/U 11/B 41/U 10/U
MLS 057/081 060/087 062/097 065/099 065/087 056/080 054/089
81/U 22/W 00/U 00/U 10/B 31/U 10/U
4BQ 057/080 060/085 062/094 066/097 065/088 057/075 054/086
81/U 22/W 00/U 00/U 10/B 41/U 10/U
BHK 054/078 056/085 056/091 061/097 061/088 054/080 052/087
82/W 22/W 00/U 10/U 11/B 31/U 11/U
SHR 050/080 052/086 053/094 058/095 057/083 051/075 048/085
51/U 11/U 00/U 00/U 11/B 43/T 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...SEVERE THUNDERSTORM WATCH 487 IN EFFECT UNTIL 9 PM MDT THIS
EVENING FOR ZONES 29>33-36-37-57-58-138-139-169-171-173-235.
WY...SEVERE THUNDERSTORM WATCH 487 IN EFFECT UNTIL 9 PM MDT THIS
EVENING FOR ZONES 198-199.
WEATHER.GOV/BILLINGS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page