652
FXUS63 KBIS 221731
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1231 PM CDT FRI MAY 22 2026
KEY MESSAGES
- SCATTERED TO NUMEROUS SHOWERS ACROSS MUCH OF WESTERN AND
CENTRAL NORTH DAKOTA THIS AFTERNOON, BECOMING WIDESPREAD AND
EXPANDING EASTWARD THROUGH THE EVENING. A FEW AFTERNOON
THUNDERSTORMS COULD PRODUCE HEAVY DOWNPOURS.
- COOLER AGAIN TODAY, WITH HIGHS MOSTLY IN THE LOWER 50S TO
LOWER 60S.
- TEMPERATURES WARM TO WELL ABOVE NORMAL FOR THE FIRST HALF OF
NEXT WEEK, WITH HIGHS MOSTLY IN THE 80S TO LOWER 90S. TUESDAY
AND WEDNESDAY COULD BE WINDY.
- OTHER THAN A FEW ISOLATED SHOWERS OR THUNDERSTORMS ON
SATURDAY, THE HOLIDAY WEEKEND IS EXPECTED TO BE DRY.
UPDATE
ISSUED AT 1230 PM CDT FRI MAY 22 2026
AS A SURFACE LOW BEGINS TO MOVE INTO NORTHERN SOUTH DAKOTA, THE
ASSOCIATED BROAD PRECPITATION SHIELD HAS BEGUN TO CROSS OVER
INTO SOUTH CENTRAL NORTH DAKOTA AT THE TIME OF THIS EARLY
AFTERNOON UPDATE. SCATTERED SHOWERS PERSIST ELSEWHERE ACROSS
WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA AT THIS
TIME. OVERALL, THE FORECAST REMAINS IN GOOD SHAPE.
UPDATE
ISSUED AT 900 AM CDT FRI MAY 22 2026
MODERATE RADAR RETURNS ARE FOUND OVER PORTIONS OF WESTERN AND
CENTRAL NORTH DAKOTA AT THE TIME OF THIS MID MORNING UPDATE.
WE'RE STARTING TO SEE SOME MORE SCATTERED, POP-UP SHOWERS
DEVELOP OVER THE NORTH CENTRAL, SLIGHTLY AHEAD OF SCHEDULE. THE
EXPECTATION IS THAT THESE SHOWERS WILL CONTINUE TO FILL IN
THROUGH THE MORNING INTO THE AFTERNOON. WITH THIS EARLIER
DEVELOPMENT, WILL NEED TO MONITOR FOR ISOLATED RUMBLES OF
THUNDER OVER THE NEXT FEW HOURS, THOUGH THE CAP IS STILL PROGGED
TO REMAIN IN PLACE THROUGH AT LEAST THE LATE MORNING. THE NEXT
SURGE OF PRECIPITATION, ASSOCIATED WITH A STACKED LOW ANALYZED
OVER SOUTHERN SOUTH DAKOTA AT THIS TIME, IS ALSO ANTICIPATED TO
SLIDE IN ACROSS CENTRAL NORTH DAKOTA LATER TODAY.
UPDATE
ISSUED AT 645 AM CDT FRI MAY 22 2026
OVERALL, THE RAIN IS UNFOLDING AS EXPECTED EARLY THIS MORNING.
MINIMAL CHANGES ARE NEEDED FOR THIS UPDATE, AND WERE BASED ON
OBSERVED AND LATEST MODELED TRENDS. THIS DID INCLUDE REMOVING
THE MENTION OF THUNDER UNTIL LATE MORNING.
DISCUSSION
ISSUED AT 432 AM CDT FRI MAY 22 2026
EARLY MORNING UPPER AIR ANALYSIS SHOWS TWO CLOSED UPPER LOWS
BOOKENDING A TROUGH AXIS FROM SOUTHERN SASKATCHEWAN TO EASTERN
WYOMING. AT THE SURFACE, AN INVERTED TROUGH AXIS LIES ACROSS THE
WESTERN DAKOTAS. THE INVERTED TROUGH HAS BEEN AND WILL CONTINUE
TO BE THE BROAD FOCAL AREA FOR SCATTERED TO NUMEROUS SHOWERS
THROUGH THE MORNING. THERE IS A RELATIVE LULL IN SHOWER ACTIVITY
AT THE TIME OF THIS WRITING, BUT THAT SHOULD QUICKLY CHANGE AS
THE LOW AT THE BASE OF THE UPPER TROUGH SPINS NORTHEASTWARD INTO
WESTERN SOUTH DAKOTA, PUSHING THE CURRENT BATCH OF RAIN OVER
THE BLACK HILLS NORTHWARD. THE CLOSED LOW WILL CONTINUE SPINNING
NORTHEASTWARD THROUGHOUT THE DAY, DRAGGING A SURFACE LOW INTO
SOUTHEAST SOUTH DAKOTA THIS AFTERNOON. STRONG SYNOPTIC SCALE
FORCING FROM MID LEVEL DCVA AND LOW LEVEL WARM AIR ADVECTION TO
THE NORTH AND NORTHEAST OF THE NEARLY-STACKED LOW PRESSURE
SYSTEM IS EXPECTED TO BRING A LARGE SHIELD OF MOSTLY STRATIFORM
RAIN ACROSS THE EASTERN TWO THIRDS OF THE STATE FROM SOUTH TO
NORTH LATER THIS MORNING THROUGH THIS EVENING. MOST OF THE STATE
OUTSIDE OF THE FAR WEST IS FAVORED TO RECEIVE AROUND A QUARTER
TO HALF INCH OF RAIN THROUGH TONIGHT, WHICH IS IN ADDITION TO
WHAT HAS ALREADY FALLEN SINCE YESTERDAY. THE JAMES RIVER VALLEY
HAS HIGHER ODDS FOR EXCEEDING HALF AN INCH, AND EVEN MEDIUM
CHANCES FOR THREE QUARTERS TO ONE INCH OF RAIN. IN CONTRAST,
THERE IS A POTENTIAL FOR A NARROW CORRIDOR OF LOWER RAIN AMOUNTS
OVER CENTRAL NORTH DAKOTA DUE TO AN AREA OF DIFFLUENCE IN THE
LOW LEVEL WIND FIELD, WHICH MAY NOT ALLOW THE AREA OF RAIN
ASSOCIATED WITH THE INVERTED SURFACE TROUGH TO FULLY ADHERE TO
THE NORTHWARD MOVING STRATIFORM RAIN SHIELD. THIS INVERTED DRY
SLOT FOOTPRINT IS QUITE PROMINENT IN THE HREF PROBABILITY-
MATCHED MEAN QPF, WHICH PLACES IT FROM THE TURTLE MOUNTAINS TO
EASTERN MORTON COUNTY. ONE FINAL NOTE ABOUT THE RAIN FORECAST
FOR TODAY IS THAT THERE IS ANOTHER POTENTIAL FOR AFTERNOON
THUNDERSTORMS, MAINLY ALONG THE INVERTED TROUGH AXIS. THE RISK
FOR STRONGER STORMS APPEARS LOWER THAN YESTERDAY, BUT ANY
TRAINING OR NEARLY-STATIONARY CONVECTION WOULD PRODUCE LOCALLY
HIGHER RAIN AMOUNTS.
REGARDLESS OF RAIN AMOUNTS, IT WILL BE A COOL AND CLOUDY DAY
FOR MOST OF THE STATE, WITH HIGHS MOSTLY IN THE 50S. LOWER 60S
COULD BE ACHIEVED ALONG THE MONTANA BORDER IF CLOUDS CLEAR EARLY
ENOUGH, AND ALSO NEAR THE TURTLE MOUNTAINS WHERE RAIN-COOLED
AIR AND THICKER CLOUD COVER MAY NOT ARRIVE UNTIL AFTER PEAK
HEATING. THE RAIN SHOULD DEPART FROM SOUTHWEST TO NORTHEAST THIS
EVENING THROUGH TONIGHT, LEAVING BEHIND A POTENTIALLY FAVORABLE
SETUP FOR FOG FORMATION. FORECAST LOWS TONIGHT ARE MOSTLY IN
THE UPPER 30S TO MID 40S. THERE COULD BE A FEW SPOTS IN
SOUTHWEST NORTH DAKOTA THAT DIP TO NEAR FREEZING, BUT AS OF THIS
WRITING, LOWS IN THE MID 30S OR COLDER ARE NOT EXPECTED TO BE
WIDESPREAD ENOUGH TO WARRANT A FROST ADVISORY.
SATURDAY WILL MARK THE BEGINNING OF A SUBSTANTIAL WARMING TREND
THROUGH THE HOLIDAY WEEKEND, WITH THE NBM PROJECTING HIGHS IN
THE UPPER 60S TO MID 70S ON SATURDAY, UPPER 70S TO MID 80S ON
SUNDAY, AND MID 80S TO LOWER 90S ON MEMORIAL DAY. FLOW ALOFT
REMAINS CYCLONIC ON SATURDAY AS THE DEPARTING MID/UPPER LEVEL
LOW STALLS OVER SOUTHERN MANITOBA. THIS COULD ALLOW A FEW
AFTERNOON SHOWERS AND THUNDERSTORMS TO DEVELOP. FORECAST CAPE
AND SHEAR PARAMETERS DO NOT APPEAR SUPPORTIVE OF SEVERE
CONVECTION ON SATURDAY, BUT A COUPLE OF CAMS DO SIMULATE A FEW
STRONGER STORMS. THE HIGHEST PROBABILITY FOR ISOLATED
THUNDERSTORMS IS IN NORTH CENTRAL NORTH DAKOTA, BUT IS STILL NO
GREATER THAN 20 PERCENT. ON SUNDAY, FLOW ALOFT TURNS QUASI-
ZONAL AS A RIDGE BUILDING OVER THE FOUR CORNERS REGION BEGINS TO
PUSH MID LEVEL HEIGHT RISES INTO THE NORTHERN PLAINS. THERE IS
UNCERTAINTY ON WHETHER AN EMBEDDED SHORTWAVE COULD BRIEFLY
INTERRUPT THE HEIGHT RISES AND INITIATE CONVECTION SUNDAY
AFTERNOON AND EVENING. IN THE 00 UTC SUITE OF GUIDANCE, THIS
FEATURE IS ONLY PRONOUNCED IN THE DETERMINISTIC GFS AND A VERY
LOW-MEMBERSHIP ENSEMBLE CLUSTER, SO WE WILL CONTINUE TO
ADVERTISE DRY WEATHER ON SUNDAY. CONFIDENCE IN DRY WEATHER IS
EVEN HIGHER ON MEMORIAL DAY AS THE UPPER RIDGE BECOMES FULLY
ESTABLISHED OVER THE NORTHERN PLAINS.
A VERY STRONG UPPER LEVEL LOW/TROUGH WILL DIG INTO THE WESTERN
CONUS BY TUESDAY, FURTHER AMPLIFYING THE CENTRAL CONUS RIDGE AND
POTENTIALLY SETTING UP AN OMEGA-BLOCKING PATTERN THROUGH THE
END OF MAY. ENSEMBLE GUIDANCE TENDS TO FAVOR THE NORTHERN PLAINS
LYING UNDER THE SOUTHERLY FLOW ALOFT PATTERN BETWEEN THE
UPSTREAM TROUGH AND DOWNSTREAM RIDGE, BUT IN CLOSER VICINITY TO
THE RIDGE. THIS RENDERS LOW PREDICTABILITY FOR ANY SHOWER AND
THUNDERSTORM CHANCES, ALTHOUGH THE NBM DOES HAVE A PERIOD OF
30-40 PERCENT POPS LATE WEDNESDAY THROUGH THURSDAY.
INTERESTINGLY, THERE IS ALSO A WEAK SIGNAL IN GEFS-BASED MACHINE
LEARNING GUIDANCE FOR A LOW-END SEVERE THUNDERSTORM RISK NEXT
WEEK. WHILE MOISTURE AND CAPE WILL CERTAINLY BE AT THE HIGHEST
THEY'VE BEEN SO FAR THIS SEASON, THE SHEAR FORECAST REMAINS
HIGHLY UNCERTAIN. HIGHER CONFIDENCE ASPECTS OF THE FORECAST FOR
NEXT WEEK UNDER THE FAVORED PATTERN ARE TEMPERATURES REMAINING
ABOVE NORMAL AND AN INCREASE IN SOUTHERLY WINDS, BOTH OF WHICH
ARE BEGINNING TO BE HIGHLIGHTED BY THE ECMWF EFI PRODUCTS.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1230 PM CDT FRI MAY 22 2026
WIDESPREAD SHOWERS AND CLOUD COVER IS INDUCING MVFR AND SOME
IFR CEILINGS AND VISIBILITY ACROSS THE FORECAST AREA TO START
THE 18Z TAF PERIOD. SHOWERS ARE EXPECTED TO SLOWLY DIMINISH
ACROSS THE WEST THIS AFTERNOON, WHILE ANOTHER PUSH OF RAIN IS
FORECAST TO MOVE ACROSS CENTRAL NORTH DAKOTA THROUGH THE
EVENING. SOME ISOLATED THUNDERSTORMS ARE POSSIBLE IN THE NORTH
CENTRAL THIS AFTERNOON INTO EARLY THIS EVENING. HAVE INCLUDED A
PROB30 GROUP FOR TSRA AT KMOT. ALL PRECIPITATION SHOULD EXIT TO
THE NORTHEAST THROUGH THE EVENING INTO EARLY TONIGHT. CEILINGS
ARE EXPECTED TO SIMILARLY IMPROVE FROM WEST TO EAST OVERNIGHT,
THOUGH MVFR CONDITIONS WILL PERSIST ACROSS CENTRAL NORTH DAKOTA
INTO SATURDAY MORNING. PATCHY FOG IS POSSIBLE ACROSS PORTIONS
OF WESTERN AND CENTRAL NORTH DAKOTA, MAINLY ALONG THE TAILING
EDGE OF THE STRATUS DECK AS IT MOVES OFF TO THE EAST OVERNIGHT.
HAVE OPTED TO INCLUDE MVFR VISIBILITY REDUCTIONS AT KDIK WITH
THIS UPDATE. ALL FOG IS GENERALLY EXPECT TO LIFT BY EARLY TO MID
SATURDAY MORNING. WINDS THIS AFTERNOON ARE EXPECTED TO BE
NORTHERLY AROUND 5 TO 10 KNOTS ACROSS THE WEST THIS AFTERNOON,
AND OUT OF THE EAST AROUND 10 TO 15 KNOTS IN CENTRAL NORTH
DAKOTA. WINDS ARE EXPECTED TO GENERALLY DIMINISH OVERNIGHT,
BECOMING LIGHT ACROSS THE WEST AND CENTRAL, THOUGH MAY REMAIN
SOMEWHAT ELEVATED AROUND 10 KNOT AND TURNING OUT OF THE EAST TO
THE NORTHWEST IN THE SOUTH CENTRAL.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...ADAM/HOLLAN
DISCUSSION...HOLLAN
AVIATION...ADAM
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