671
FXUS65 KBYZ 040704
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
104 AM MDT FRI JUL 4 2025
KEY MESSAGES
- COOLER TEMPERATURES TODAY INTO SUNDAY.
- 30-60 PERCENT CHANCE SHOWERS AND THUNDERSTORMS THIS AFTERNOON
AND EVENING. SEVERE THUNDERSTORM CHANCES ARE LOW. NOT A WASH
OUT FOR FIREWORKS ACTIVITIES.
- SCATTERED STRONG TO SEVERE THUNDERSTORMS POSSIBLE SATURDAY
AFTERNOON AND EVENING. BE WEATHER AWARE AND HAVE PLANS TO SEEK
SHELTER IF STORMS APPROACH.
- HOT AND MAINLY DRY NEXT WEEK, 90S TO NEAR 100 TUESDAY THROUGH
THURSDAY.
DISCUSSION
THROUGH SATURDAY NIGHT...
DISTURBANCE EJECTING OUT OF THE GREAT BASIN WILL KEEP LOW CHANCES
FOR A SHOWER OR THUNDERSTORM IN THE FORECAST THROUGH THE EARLY
MORNING HOURS (2AM). THERE SHOULD BE A BREAK IN ACTIVITY UNTIL 9
OR 10 AM WHEN ANOTHER DISTURBANCE MOVES INTO THE SOUTH CENTRAL
PORTION OF THE FORECAST AREA DEVELOPING SCATTERED SHOWERS AND A
THUNDERSTORM OR TWO OVER THE EASTERN HALF OF THE FORECAST AREA
THROUGH EARLY AFTERNOON. PRECIPITATION ACCUMULATIONS WITH BOTH OF
THESE DISTURBANCES WILL BE LIGHT (UNDER 0.10 IN).
BETTER ENERGY AND UPPER DIFFLUENCE, ALONG WITH STRONGER
INSTABILITY THANKS TO TEMPERATURES REACHING THE MID TO UPPER 80S,
WILL BRING A BETTER CHANCE (30-60%) FOR SHOWERS AND THUNDERSTORMS
TO THE AREA FROM 3 TO 10PM TODAY. BASED ON NBM PRECIPITATION
ACCUMULATION FORECASTS, THE HEAVIEST PRECIPITATION POTENTIAL LOOKS
TO BE LATE AFTERNOON INTO THE VERY EARLY EVENING (3-7PM), SO IT
DOES NOT LOOK TO BE A WASH OUT FOR LATE EVENING FIREWORKS
ACTIVITY. THAT SAID, IF STORMS APPROACH PLEASE POSTPONE OUTDOOR
ACTIVITIES AND HEAD INDOORS UNTIL STORMS PASS.
A PACIFIC TROF THAT HAS BEEN HANGING OUT OVER THE PACNW FOR THE
PAST FEW DAYS FINALLY DISLODGES AND PUSHES THROUGH THE NORTHERN
ROCKIES AND INTO THE NORTHERN PLAINS SATURDAY. STRONGER
INSTABILITY AND SHEAR WILL BRING THE POTENTIAL FOR SCATTERED
STRONG TO POSSIBLY SEVERE THUNDERSTORMS SATURDAY AFTERNOON CENTRAL
AND WEST, AND SATURDAY EVENING OVER SE MONTANA. THE HREF IS
SHOWING NUMEROUS STRONGER HELICITY TRACKS ALONG WITH WIDESPREAD
STRONG TO DAMAGING WIND SIGNATURES DURING THIS TIME. NCAR NEURAL
NET SEVERE PROBABILITIES FOR SATURDAY PEAK IN THE 20 TO 30 PERCENT
RANGE FOR A BROAD PORTION OF THE FORECAST AREA, WHILE UPDRAFT
HELICITY BASED PROBABILITIES ARE HIGHER IN THE 30 TO 50 PERCENT
RANGE FOR SEVERE THUNDERSTORMS. SPC CURRENTLY SHOWS A MARGINAL
RISK FOR SATURDAY MAINLY OVER SE MONTANA, BUT BASED ON THE LATEST
HREF AND NCAR FORECASTS WOULD ANTICIPATE A HIGHER RISK CATEGORY
COVERING MORE OF THE FORECAST AREA WITH SUBSEQUENT ISSUANCE'S.
THOSE WITH OUTDOOR PLANS SATURDAY SHOULD PAY CLOSE ATTENTION TO
THE WEATHER AND HAVE A PLAN TO SEEK SHELTER IF STORMS APPROACH.
COOLER PACIFIC AIR WILL PUSH HIGHS DOWN INT THE 70S OVER THE
WESTERN FOOTHILLS, WITH LOW TO MID 80S ELSEWHERE ON SATURDAY.
CHAMBERS
SUNDAY THROUGH THURSDAY...
UPPER TROF EXITS THE AREA TO THE EAST ON SUNDAY, WITH WEAK
WESTERLY FLOW BUILDING INTO THE AREA BEHIND IT. SHOULD BE ENOUGH
RESIDUAL MOISTURE AROUND TO KEEP A SLIGHT CHANCE FOR
AFTERNOON/EVENING CONVECTION IN THE FORECAST, BUT OVERALL NOT A
BAD DAY TO GET OUTDOORS WITH HIGHS IN THE UPPER 70S TO LOWER 80S.
BY MONDAY AN UPPER RIDGE BEGINS TO TAKE HOLD FROM THE GREAT BASIN
NORTH ALONG THE SPINE OF THE ROCKIES. THIS RIDGING HOLDS THROUGH
THE REST OF THE FORECAST PERIOD, THOUGH THERE ARE SOME HINTS OF A
RIDGE CRASHER DISTURBANCE ARRIVING THURSDAY AFTERNOON/EVENING.
UNDER THE RIDGE CHANCES FOR AFTERNOON AND EVENING THUNDERSTORMS
DROP TO UNDER 15% EACH DAY AND TEMPERATURES WARM WELL INTO THE
90S BY TUESDAY, WITH A FEW TRIPLE DIGITS POSSIBLE WEDNESDAY AND
MAYBE THURSDAY TOO. CHAMBERS
AVIATION
CONVECTION WILL CONTINUE OVER THE FORECAST AREA INTO THE EARLY
MORNING HOURS, DIMINISHING FOR THE MOST PART BY 10Z. THUNDERSTORMS
SHOULD BE CONFINED TO AREAS EAST OF A MILES CITY TO BROADUS LINE
DURING THIS PERIOD. ANOTHER PERIOD OF ISOLATED TO SCATTERED SHOWER
ACTIVITY IS FORECAST TO BEGIN AROUND 15Z OVER SOUTH CENTRAL
AREAS, COVERING THE EASTERN HALF OF THE FORECAST AREA. CAN'T RULE
OUT AN ISOLATED EMBEDDED THUNDERSTORM WITH THIS ACTIVITY. A
STRONGER SHORTWAVE AND BETTER INSTABILITY ARRIVES FOR THE
AFTERNOON AND EVENING HOURS WITH SCATTERED CONVECTION MOVING FROM
THE WESTERN FOOTHILLS EASTWARD TO ENCOMPASS THE FORECAST AREA FROM
21Z-03Z TIME FRAME, DIMINISHING BY MIDNIGHT. STRONG WIND GUSTS TO
45KTS WILL BE THE MAIN THREAT WITH THIS AFTERNOON AND EVENING
CONVECTIVE PERIOD. OUTSIDE OF LOCAL MVFR CONDITIONS NEAR STRONGER
THUNDERSTORMS, VFR CONDITIONS WILL PREVAIL. CHAMBERS
PRELIMINARY POINT TEMP/POPS
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 086 058/081 055/083 058/087 060/095 063/098 064/094
4/T 47/T 41/U 11/U 10/U 00/U 11/B
LVM 080 048/076 045/081 049/087 052/093 056/095 056/090
7/T 67/T 21/U 11/U 10/U 00/U 11/U
HDN 088 058/084 054/083 055/089 058/095 061/098 061/095
3/T 47/T 50/U 11/U 10/U 00/U 11/B
MLS 089 063/085 057/082 058/087 061/095 064/098 064/096
4/T 65/T 71/U 11/U 10/U 10/U 11/B
4BQ 085 061/085 058/081 058/086 061/092 064/095 064/095
4/T 44/T 71/U 21/U 10/U 10/U 11/B
BHK 083 058/080 054/078 055/084 057/088 060/093 060/092
4/T 54/T 82/W 11/U 10/U 10/U 11/B
SHR 083 053/083 049/081 052/086 054/092 057/095 058/092
6/T 36/T 41/U 11/U 11/U 00/U 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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