008
FXUS63 KBIS 022058
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
358 PM CDT MON JUN 2 2025
KEY MESSAGES
- NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES EXPECTED THIS WEEK,
WITH A SLIGHT WARMUP HEADING INTO THE WEEKEND.
- DAILY LOW TO MEDIUM CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THE WEEKEND, LOWEST ON TUESDAY (AROUND 10 PERCENT)
AND HIGHEST ON SATURDAY (AROUND 40 PERCENT).
DISCUSSION
ISSUED AT 356 PM CDT MON JUN 2 2025
NORTH DAKOTA SITS UNDER SOUTHWEST FLOW ALOFT ASSOCIATED WITH A
CLOSED UPPER LOW SPINNING JUST WEST OF HUDSON BAY THIS AFTERNOON.
THE SURFACE AIR MASS IS POST-COLD FRONTAL WITH A SOUTHWEST-NORTHEAST
ORIENTED SURFACE RIDGE DIVIDING GUSTY NORTHERLY WINDS TO THE SOUTH
AND LIGHTER NORTHWESTERLY WINDS TO THE NORTH. STRONG DCVA EMINATING
FROM THE BASE OF AN UPPER TROUGH OVER THE MONTANA ROCKIES AS WELL AS
A 700 MB TROUGH CUTTING FROM NORTHEAST TO SOUTHWEST NORTH DAKOTA
CONTINUE TO PROMOTE AREAS OF LIGHT RAIN SHOWERS THIS AFTERNOON, WITH
THE GREATEST CONCENTRATION FROM THE SOUTH CENTRAL TO NORTHEAST AS OF
330 PM CDT. BOTH SATELLITE IMAGERY AND SPC MESOANALYSIS SUGGEST IT
HAS NOW BECOME TOO STABLE TO SUPPORT ANY MORE THUNDERSTORMS IN OUR
FORECAST AREA. THE SHOWERS ARE FORECAST TO DISSIPATE AND SHIFT
EASTWARD THROUGH THE REST OF THE AFTERNOON, BUT A SEPARATE AREA OF
MORE POPCORN-TYPE SHOWERS IN SOUTHERN SASKATCHEWAN THAT ARE
ASSOCIATED WITH ANOTHER SURGE OF DCVA COULD MOVE INTO NORTHWEST
NORTH DAKOTA THIS EVENING. A QUIET BUT SEASONABLY COOL OVERNIGHT
PERIOD IS EXPECTED AS SURFACE HIGH PRESSURE EXPANDS ACROSS MONTANA.
LOWS TONIGHT WILL MAINLY BE IN THE 40S.
A QUASI-ZONAL CYCLONIC FLOW PATTERN IS FORECAST OVER THE NORTHERN
PLAINS TUESDAY THROUGH THURSDAY. THE NBM SHOWS HIGH CONFIDENCE IN
HIGH TEMPERATURES IN THE UPPER 60S TO MID 70S AND LOW TEMPERATURES
IN THE 40S OVER THIS TIME PERIOD. DAILY LOW CHANCES FOR RAIN (10 TO
30 PERCENT) ARE IN THE FORECAST TUESDAY THROUGH THURSDAY, WHICH
SHOULD MOSTLY COME IN THE FORM OF SCATTERED AFTERNOON SHOWERS
INITIATED BY DESTABILIZATION OF THE BOUNDARY LAYER UNDERNEATH THE
CYCLONIC FLOW. TUESDAY HAS THE LOWEST CHANCES FOR SHOWERS, AND ANY
THAT DO DEVELOP ARE LIKELY TO BE LIMITED TO NORTHERN PARTS OF THE
STATE. THERE MAY BE ENOUGH BUOYANCY TO SUPPORT A FEW ISOLATED
THUNDERSTORMS WEDNESDAY AND THURSDAY DURING THE AFTERNOON AND EARLY
EVENING, BUT WIDESPREAD ORGANIZED CONVECTION IS NOT EXPECTED.
A SUBTLE SHIFT IN THE UPPER LEVEL PATTERN TO A SLIGHTLY AMPLIFIED
NORTHWEST FLOW IS BEING ADVERTISED FOR FRIDAY AND SATURDAY. THIS
BRINGS A SLIGHT WARMUP TO THE ENSEMBLE TEMPERATURE DISTRIBUTION,
WITH THE LATEST NBM FAVORING HIGHS AROUND 75 TO 80 ON FRIDAY AND 80
TO 85 ON SATURDAY. THERE IS INCREASING ENSEMBLE SUPPORT FOR A POTENT
SHORTWAVE/CLOSED LOW DIGGING INTO THE UPPER MIDWEST BY SUNDAY. 3 OUT
OF 4 ENSEMBLE CLUSTERS COMPOSING 80 PERCENT OF THE TOTAL ENSEMBLE
MEMBERSHIP SUPPORT THE CLOSED LOW SOLUTION VS. A WEAKER OPEN WAVE,
ALBEIT WITH SPATIAL AND TEMPORAL DISPARITIES. PRIOR TO THE ARRIVAL
OF THE UPPER WAVE/LOW, THERE IS HIGHER FORECAST CONFIDENCE THAT IT
WILL DRIVE A SURFACE COLD FRONT ACROSS THE REGION ON SATURDAY, BUT
WITH TIMING UNCERTAINTY. THE NBM HAS ACCORDINGLY INCREASED CHANCES
FOR SHOWERS AND THUNDERSTORMS TO AROUND 40 PERCENT ON SATURDAY.
PROSPECTS FOR SEVERE CONVECTION REMAIN LOW AT THIS TIME, WITH THE
CURRENT SUITE OF ENSEMBLES PROJECTING MARGINALLY SUFFICIENT CAPE BUT
WEAK SHEAR. THE COLD FRONTAL PASSAGE AND ARRIVAL OF THE UPPER
WAVE/LOW MAY COOL TEMPERATURES BACK TO BELOW AVERAGE FOR SUNDAY, BUT
THERE IS A CONSIDERABLE INCREASE IN ENSEMBLE SPREAD COMPARED TO THE
PRECEDING DAYS
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 356 PM CDT MON JUN 2 2025
AREAS OF SHOWERS WILL CONTINUE TO MOVE ACROSS CENTRAL AND
EASTERN NORTH DAKOTA THIS AFTERNOON. MOST OF THIS ACTIVITY WILL
END BY EARLY EVENING, BUT SOME LINGERING ISOLATED SHOWERS COULD
RE-ENTER WESTERN NORTH DAKOTA DURING THE EVENING. CEILINGS ARE
EXPECTED TO PREVAIL AT VFR LEVELS, THOUGH FAR SOUTHWEST NORTH
DAKOTA (NOT INCLUDING KDIK) COULD SEE BRIEF PERIODS OF MVFR
CEILINGS THIS AFTERNOON. SOUTHERN AND EASTERN NORTH DAKOTA WILL
CONTINUE TO SEE GUSTY NORTHERLY WINDS THIS AFTERNOON, WITH
LIGHTER AND MORE VARIABLE WINDS TO THE NORTH. FOR TONIGHT
THROUGH TUESDAY MORNING, EXPECT WEST-NORTHWEST WINDS AROUND 10
KTS.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HOLLAN
AVIATION...HOLLAN
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