325
FXUS65 KBYZ 200651
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1251 AM MDT MON APR 20 2026
KEY MESSAGES
- WARM AND DRY INTO WEDNESDAY. EXPECT SOME RISES ON STREAMS AND
RIVERS DUE TO MOUNTAIN SNOWMELT. USE CAUTION WITH BURNING.
- IMPACTFUL WEATHER SYSTEM LIKELY LATE WEDNESDAY THROUGH FRIDAY.
POTENTIAL IMPACTS FROM STRONG WINDS, PRECIPITATION (RAIN AND
SNOW), AND COOLER TEMPERATURES. COOL/WET/WINDY WEATHER MAY BE
HAZARDOUS FOR YOUNG LIVESTOCK.
DISCUSSION
TODAY THROUGH SUNDAY...
SATELLITE IMAGERY SHOWS AN UPPER LEVEL RIDGE OVER THE NORTHERN
ROCKIES AND AN UPSTREAM CUT OFF LOW OFF THE PACIFIC COAST. THERE
IS A SHORTWAVE TRACKING THRU NORTHERN AB INTO SK WHICH WILL BRING
A WEAK BACKDOORING WIND SHIFT LATER TODAY AND TONIGHT, BUT WITHOUT
MUCH IMPACT IN TERMS OF TEMPS AS THE RIDGE AND WARMER AIR EMERGING
FROM THE SW REMAIN DOMINANT THE NEXT COUPLE OF DAYS. LOOK FOR
TEMPS IN THE 70S TO NEAR 80F TODAY, THEN MOSTLY 80S TUESDAY
(LIKELY TO BE THE WARMEST DAY YET OF 2026). WEDNESDAY WILL SEE THE
ONSET OF HEIGHT FALLS AS THE THERMAL LOW SHIFTS TO OUR EAST, THUS
UPPER 60S WEST TO MID 80S EAST FOR HIGHS. WINDS TODAY & TOMORROW
WILL NOT BE STRONG (ONLY MODEST BREEZY MIXED WINDS OVER THE
WESTERN FOOTHILLS TUESDAY), BUT DEEPENING LEE SIDE LOW PRESSURE
SUPPORTS HIGHER PRE-FRONTAL GUSTS ON WEDNESDAY...PERHAPS UP TO ~45
MPH IN THE WEST. THE HEAT, DRY AIR AND BREEZY WINDS SUGGEST
WEDNESDAY IS THE MOST CONCERNING DAY WITH REGARD TO FIRE WX, BUT
GREENING IS UNDERWAY AND WILL LIMIT THE GRASS FIRE RISK. THAT
SAID, WE ARE LOOKING AT VERY WARM TEMPS, NEARING RECORD HIGHS IN
SPOTS, SO PLEASE TAKE CARE TO NOT SPARK A FIRE.
WEATHER GETS MUCH MORE INTERESTING STARTING LATE WEDNESDAY AS THE
AFOREMENTIONED PACIFIC LOW GETS EJECTED THROUGH THE INTERMOUNTAIN
WEST IN SOME FASHION, WHILE MORE ENERGY DROPS OUT OF NW CANADA AND
POTENTIALLY PHASES WITH IT INTO THURSDAY/FRIDAY. FIRST SOME THINGS
WE KNOW. SYNOPTIC SCALE ASCENT INCREASES LATE WEDNESDAY INTO
THURSDAY AS THE LOW TAKES ON A NEGATIVE TILT AS IT APPROACHES. SO
SHOWERS LIKELY INCLUDING MOUNTAIN SNOWFALL. THERE IS A LOW RISK OF
T-STORMS AS WELL, WHICH MAY INCLUDE WEDNESDAY NIGHT EAST OF
BILLINGS PER THE STRONG FORCING W/ THE LOW. ON THE BACK SIDE OF
THE LOW, NW WINDS WILL INCREASE AND COULD BECOME QUITE STRONG FOR
THURSDAY AND TO A LESSER DEGREE INTO FRIDAY. THIS BRINGS US TO THE
MANY UNCERTAINTIES. THE PRECISE TRACK OF THE LOW WILL DICTATE
PRECIP LOCATION/MAGNITUDE AS THE LOW MOVES INTO MT/WY AND WITH THE
ASSOCIATED TROWAL ON ITS BACK SIDE. AS ALWAYS, A TRACK THRU
NORTHERN WY KEEPS US IN ITS DIFFLUENT REGION LONGER (THUS WETTER),
WHILE A TRACK MORE QUICKLY INTO MT SUPPORTS MORE WIND. ENSEMBLES
SHOW A SOLID SIGNAL FOR POST-FRONTAL NW WINDS ESPECIALLY FROM
BILLINGS EASTWARD, WHERE THE PROBABILITIES FOR 60+ MPH GUSTS ARE
30-70% (GREATEST ALONG THE EAST SIDE OF THE BIGHORNS AND CLOSE TO
THE DAKOTAS BORDER). PTYPE IS ALSO A CONCERN AS DYNAMIC COOLING
COULD FORCE A CHANGEOVER TO WET SNOW, WHICH COULD BE SIGNIFICANT.
THE PROBABILITIES FOR 3+ INCHES OF SNOW FROM WEDNESDAY TO FRIDAY
ARE NON-ZERO ACROSS LOWER ELEVATIONS, AT ROUGHLY 10-30%, GREATEST
OVER THE HIGHER HILLS. MOUNTAINS WILL PICK UP SEVERAL INCHES OF
SNOW (6-12") DURING THIS TIME. IMPLICATIONS WITH THE SHORTWAVE
DROPPING OUT OF CANADA ARE QUITE INTERESTING AS IF THERE IS ENOUGH
PHASING WITH THE INITIAL LOW, THE ENTIRE SYSTEM SLOWS UP AND
IMPACTS PERSIST THRU THE END OF THE WEEK AND INTO THE WEEKEND.
ENSEMBLES SHOW A GREAT DEAL OF SPREAD HERE, BUT CLUSTER ANALYSES
SUPPORT BELOW NORMAL HEIGHTS AND CYCLONIC FLOW THROUGH THE
WEEKEND. AS A RESULT, WE CAN BE CONFIDENT OF COOLER THAN NORMAL
TEMPS THURSDAY THRU SUNDAY, WITH AT LEAST A LOW CHANCE OF PRECIP
EACH DAY.
POTENTIAL IMPACTS WITH THE WEDNESDAY NIGHT-FRIDAY SYSTEM INCLUDE
TRAVEL (DUE TO WIND AND MAYBE SNOWFALL) AND HAZARDOUS CONDITIONS
FOR YOUNG LIVESTOCK (PER COOL/WET/WINDY WEATHER). PLEASE MONITOR
THE FORECAST OVER THE COMING DAYS AS DETAILS BECOME CLEARER.
JKL
AVIATION
VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH THE FORECAST
PERIOD. NO SIGNIFICANT IMPACTS TO AVIATION ARE EXPECTED. BT
PRELIMINARY POINT TEMP/POPS
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 079 047/086 053/077 039/047 031/046 027/049 028/049
0/U 00/U 14/T 87/O 34/J 21/B 12/W
LVM 077 044/080 047/067 034/043 025/042 021/046 023/047
0/U 00/N 05/T 98/O 45/J 22/J 12/J
HDN 080 042/087 050/081 037/048 028/047 025/050 027/051
0/U 00/U 14/T 98/R 35/W 22/J 12/W
MLS 077 044/085 054/084 038/046 028/043 025/046 025/048
0/U 00/U 02/T 79/T 33/J 21/B 11/B
4BQ 078 043/084 054/083 037/046 029/044 025/046 026/050
0/U 00/U 01/B 69/T 32/J 21/B 11/B
BHK 075 041/084 049/084 036/046 025/040 022/042 022/047
0/U 00/U 01/B 49/T 42/J 21/B 11/B
SHR 078 040/085 046/080 035/046 024/043 020/046 022/047
0/U 00/U 02/T 79/O 45/J 32/J 22/W
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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