953
FXUS63 KBIS 250930
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
430 AM CDT SAT OCT 25 2025
KEY MESSAGES
- PATCHY TO AREAS OF FOG THIS MORNING.
- ABOVE NORMAL TEMPERATURES FOR LATE OCTOBER TODAY (FORECAST
HIGHS IN THE 60S TO AROUND 70, WITH NORMAL VALUES IN THE LOWER
50S).
- PRECIPITATION CHANCES RETURN SUNDAY NIGHT AND CONTINUE INTO
MONDAY NIGHT/TUESDAY. GREATEST CHANCES CENTRAL INTO EASTERN
NORTH DAKOTA MONDAY (50 TO 80 PERCENT).
- NEAR NORMAL TEMPERATURES EXPECTED FOR THE UPCOMING WORK WEEK.
DISCUSSION
ISSUED AT 410 AM CDT SAT OCT 25 2025
CURRENTLY, HIGH AMPLITUDE UPPER LEVEL RIDGE ACROSS THE NORTHERN
PLAINS THIS MORNING, WITH A LONG WAVE TROUGH DEVELOPING ACROSS
THE WESTERN CONUS. SOUTHERLY FLOW ACROSS THE DAKOTAS WITH
SURFACE HIGH PRESSURE OVER THE GREAT LAKES REGION AND A
DEVELOPING SFC TROUGH IN THE LEE OF THE NORTHERN ROCKIES.
SCATTERED UPPER LEVEL CLOUDS ROTATING AROUND THE RIDGE AXIS
ALOFT, WITH A MILD BOUNDARY LAYER CONTRIBUTED TO MORNING
TEMPERATURES MAINLY ABOVE FREEZING EARLY THIS MORNING. HIGH RES
MODELS CONTINUE TO PORTRAY FOG DEVELOPMENT ACROSS THE JAMES
RIVER VALLEY THIS MORNING, WITH THIS UNDERWAY NOW AS EVIDENT VIA
SATELLITE IMAGERY. AREA OF LOW STRATUS ALSO ADVECTING NORTHWARD
ACROSS THE SOUTH DAKOTA JAMES VALLEY TOWARDS MY SOUTHEAST
COUNTIES. WILL BE MONITORING THIS AREA FOR POTENTIAL FOG
HEADLINES. RIGHT NOW AERIAL COVERAGE IS LIMITED AND SOME
UNCERTAINTY WHAT THE STRATUS WILL DO TO ANY FOG.
GRADIENT FORCING INCREASES ACROSS THE DAKOTAS TODAY AS THE LEE
SIDE SFC LOW CONTINUES TO DEVELOP IN RESPONSE TO THE ABOVE
MENTIONED UPPER TROUGH DEVELOPING EAST TODAY. THE INCREASE IN
RETURN FLOW/MIXING AND THE POSITION OF THE UPPER RIDGE AXIS
WILL ALL CONTRIBUTE TO SUSTAINED WAA AND ANOTHER DAY OF VERY
MILD TEMPERATURES TODAY (MID/UPPER 60S-LOWER 70S
FORECAST...WITH NORMAL HIGH TEMPS IN THE LOWER 50S).
THE INITIAL EVOLUTION OF THE OVERALL WEATHER PATTERN REMAINS
UNCHANGED FROM PREVIOUS MODEL RUNS LATE THIS WEEKEND. THE UPPER
TROUGH CONTINUES TO DEVELOP EASTWARD SUNDAY, WITH A STRONG 150
KNOT JET STREAK POKING INTO THE PACIFIC NORTHWEST. INITIAL
CLOSED UPPER LOW DEVELOPS WITHIN THE TROUGH, LIFTING
NORTH/NORTHEAST INTO CENTRAL ALBERTA/SASKATCHEWAN SUNDAY/SUN
NIGHT ALONG WITH AN ASSOCIATED SFC LOW. ANOTHER STRONG EMBEDDED
IMPULSE AND STRONG DYNAMICS ON THE NOSE OF THE UPPER JET WILL
AMPLIFY THE MID/UPPER LEVEL TROUGH SUN NIGHT INTO MONDAY, WITH
AN ASSOCIATED SFC TROUGH/FRONTAL BOUNDARY DEVELOPING FROM ACROSS
EASTERN COLORADO NORTH/NORTHEAST ACROSS CENTRAL SOUTH AND NORTH
DAKOTA. THIS FEATURE COUPLED WITH MULTIPLE EMBEDDED WAVES
LIFTING NORTH/NORTHEAST FROM THE BASE OF THE TROUGH ACROSS THE
DAKOTAS WILL BE THE FOCUS FOR ACCUMULATING RAINFALL. MODELS/NBM
HAVE SHIFTED BACK WEST WITH THE SFC TROUGH/FRONTAL BOUNDARY
PLACEMENT, AND THUS HAVE SHIFTED WEST FOR POPS AND QPF. DECENT
ACCUMULATIONS ARE ALSO ADVERTISED BY NBM (QUARTER TO 3 QUARTERS
OF AN INCH CENTRAL AND EAST), AND AGREE GIVEN THE OVERLAP OF
DIV Q FORCING AND LOW LEVEL FORCING/FRONTOGENESIS. RAIN CHANCES
GRADUALLY TAPER OVER THE WEST OVERNIGHT MONDAY, WITH CHANCES
GRADUALLY TAPERING ELSEWHERE FROM WEST TO EAST EARLY TUESDAY.
AFTERWARDS, A FAIRLY PROGRESSIVE PATTERN IS FAVORED AMONGST
ENSEMBLES FOR THE REMAINDER OF THE WORK WEEK, WITH MODELS
SHOWING THE POTENTIAL FOR A MID LEVEL SHORTWAVE/FRONTAL
PASSAGE MID TO LATE NEXT WEEK. TEMPERATURES ARE ALSO FAVORED TO
BE CLOSER TO NORMAL FOR NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 112 AM CDT SAT OCT 25 2025
VFR CONDITIONS WITH SOME HIGH CLOUDS MOVING ACROSS THE REGION
DURING THE 06 TAF PERIOD. PATCHY TO AREAS OF FOG FORECAST LATER
THIS MORNING, MAINLY ACROSS THE JAMES RIVER VALLEY IMPACTING
KJMS (IFR-LIFR CONDITIONS WILL BE POSSIBLE). BREEZY SOUTHERLY
WINDS EXPECTED DURING THE DAY SATURDAY, WITH LLWS POSSIBLE
ACROSS CENTRAL AREAS OF NORTH DAKOTA SATURDAY EVENING/NIGHT.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...NH
AVIATION...NH
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