194
FXUS65 KBYZ 290216
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
816 PM MDT THU AUG 28 2025
KEY MESSAGES
- CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE REGION
THROUGH SATURDAY (MODERATE TO HIGH CHANCE). LOCALLY HEAVY
RAINFALL IS POSSIBLE WITH STRONGER SHOWERS/THUNDERSTORMS.
- FLASH FLOOD POTENTIAL IS ELEVATED IN AND NEAR AREA BURN SCARS
THROUGH SATURDAY.
- WARMER AND DRY SUNDAY THROUGH TUESDAY.
UPDATE
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE SPREAD ACROSS THE
AREA THIS EVENING. RADAR ESTIMATED PRECIPITATION FOR THE PAST 12
HOURS SHOWS AREAS OF AROUND AN INCH IN SEVERAL AREAS (MAINLY OVER
THE WESTERN FOOTHILLS) AND ONE SMALL AREA OF NEAR 2 INCHES IN FAR
NW ROSEBUD COUNTY. OTHERWISE PRECIPITATION AMOUNTS HAVE BEEN
GENERALLY LIGHT ACROSS THE AREA WITH A LOT OF GAUGE REPORTS IN THE
0.01 TO 0.15 INCH RANGE. MODELS CONTINUE TO SHOW AN AREA OF
UPGROWTH IN ACTIVITY ALONG A SURFACE CONVERGENCE LINE, FROM NEAR
ROUNDUP SOUTH INTO THE BILLINGS AREA AND THEN SOUTHEAST INTO BIG
HORN COUNTY, OVER THE NEXT FEW HOURS. THIS AREA THEN PUSHES
SLOWLY EASTWARD OVERNIGHT. ADDITIONAL LIGHT SHOWER ACTIVITY
FILLS IN TO THE WEST THROUGH TOMORROW MORNING KEEPING
PRECIPITATION CHANCES GOING MOST LOCATIONS. ADJUSTED THE FORECAST
TO ACCOUNT FOR THE LATEST MODEL TRENDS WHICH CONTINUE 20 TO 60
PERCENT PRECIPITATION CHANCES INTO TOMORROW. PRECIPITATION AMOUNTS
WILL VARY, WITH AREAS SITTING UNDER THE STRONGER SLOW MOVING
CELLS PICKING UP A QUICK QUARTER TO HALF AN INCH WHILE OTHER
AREAS SEE VERY LIGHT ACCUMULATIONS, OR NOTHING AT ALL. EXPECT
PATCHY FOG ACROSS THE AREA WITH LIGHT UPSLOPE FLOW AND CURRENT RH
VALUES ALREADY ELEVATED DUE TO ONGOING PRECIPITATION. TEMPERATURES
IN MOST AREAS ARE ALREADY IN THE 60S TO LOW 70S AT 8PM. CLOUD
COVER WILL HELP HOLD TEMPERATURES IN THE UPPER 50S TO LOWER 60S
OVERNIGHT DESPITE THE COOL TEMPERATURES ALREADY IN PLACE THIS
EVENING. CHAMBERS
DISCUSSION
TONIGHT THROUGH SATURDAY...
A 500 MB WAVE WILL CONTINUE TO MOVE THROUGH THE REGION TONIGHT
BRINGING CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS. A LOW
PRESSURE SYSTEM IN WYOMING WILL BRING SOUTHEAST WINDS CREATING A
NORTHWEST TO SOUTHEAST ORIENTED MOISTURE AXIS OVER MONTANA WITH
PWATS NEAR 1.25 INCHES. THIS MOISTURE AXIS ALIGNS WELL WITH
850-300 MB MEAN WIND CREATING FAVORABLE CONDITIONS FOR HEAVY RAIN.
THIS RESULTS IN A RISK LEVEL 1 OF 4 FOR EXCESSIVE RAINFALL
TONIGHT.
AS THE 500 MB WAVE MOVES TO THE EAST, DETERMINISTIC MODELS ARE
INDICATING A BROAD LOW PRESSURE SYSTEM OVER THE WESTERN HIGH
PLAINS THAT WILL CONTINUE TO WRAP MOISTURE INTO MONTANA. THIS WILL
CREATE CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS FRIDAY AND
SATURDAY. MOST LOCATIONS HAVE A 30-60% CHANCE OF GETTING GREATER
THAN 0.25 INCHES OF PRECIPITATION. BY SUNDAY, UPPER LEVEL RIDGING
AND RISING HEIGHTS START TO WORK INTO THE REGION PUSHING
PRECIPITATION CHANCES OFF TO THE EAST.
TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL FRIDAY AND SATURDAY
WITH 850 MB TEMPERATURE ANOMALIES OF 0 TO -5 C. HIGH TEMPERATURES
WILL BE IN THE 70S F FOR MOST. TORGERSON
SUNDAY THROUGH THURSDAY...
THERE IS GREATER AGREEMENT AMONGST THE CLUSTER MEMBERS TODAY THAT
NEXT WEEK WILL BE DOMINATED BY A FAIRLY HIGH AMPLITUDE RIDGE. THIS
WILL ALLOW FOR TEMPERATURES TO BE ABOVE STARTING SUNDAY. THERE IS
STILL SOME DISAGREEMENT REGARDING ON HOW FAR EAST THE HIGHER
HEIGHTS WILL REMAIN IN PLACE WHICH COULD BE IMPACTFUL ONCE VORT
MAXES START TO MOVE ALONG THE JET.
LONG RANGE MODELS SHOW A SHORTWAVE RAPIDLY MOVE SOUTHEASTWARDS OUT
OF THE CANADIAN ROCKIES ON TUESDAY WHICH COULD BRING CHANCES FOR
PRECIP. THERE IS A NOTABLE DIFFERENCE BETWEEN THE GFS AND ECMWF
AT THIS TIME AS THE EURO SOLUTIONS ARE MUCH MORE MOIST THAN THOSE
OF THE GFS. THE NBM SEEMS TO HAVE TRENDED TOWARDS THAT OF THE GFS
AT THIS TIME AS IT IS SHOWING <25% CHANCE OF A WETTING RAIN
EVERYWHERE OUTSIDE OF THE MOUNTAINS. I AM INCLINED TO HEDGE MY
PREDICTION TOWARDS THAT OF THE DRIER MODELS AS THERE DOES NOT SEEM
TO BE ANY GOOD ANY REALISTIC MOISTURE ADVECTION PRESENT DUE TO
THE NORTHERLY COMPONENT OF THE FLOW THROUGHOUT THE COLUMN. WMR
AVIATION
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE SPREADING EAST
THIS EVENING. HEAVY RAIN WITH ANY STRONGER RAIN
SHOWER/THUNDERSTORM HAS THE POTENTIAL TO CREATE MVFR CONDITIONS.
SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE (40-70%)
AT ALL TAF SITES FRIDAY. EXPECT MOUNTAIN OBSCURATION THROUGH THE
PERIOD. TS/TORGERSON
PRELIMINARY POINT TEMP/POPS
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 061/075 057/079 055/087 057/088 057/084 055/079 052/083
55/T 32/T 00/U 00/U 01/U 11/B 00/U
LVM 050/076 049/079 048/085 049/086 050/084 049/081 047/082
75/T 32/T 00/U 00/U 02/T 11/U 11/U
HDN 058/076 055/077 051/087 053/088 053/084 052/078 048/082
55/T 43/T 10/U 00/U 01/U 11/B 10/U
MLS 060/077 058/077 055/084 056/088 055/081 051/073 047/079
33/T 33/W 10/U 00/U 11/B 21/B 10/U
4BQ 057/072 057/071 053/079 054/084 055/081 052/072 047/077
64/T 44/T 20/U 00/U 01/U 21/B 10/U
BHK 055/076 053/076 051/080 052/083 053/078 045/070 042/075
23/W 33/T 20/U 00/U 11/B 21/B 10/U
SHR 052/074 050/073 047/082 049/084 050/082 049/076 045/080
66/T 45/T 10/U 00/U 01/U 22/W 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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