801
FXUS63 KBIS 300301
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1001 PM CDT TUE JUL 29 2025
KEY MESSAGES
- ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF
WESTERN NORTH DAKOTA THIS EVENING. EXPECTED HAZARDS INCLUDE
HAIL AS LARGE AS HALF DOLLARS AND WIND GUSTS UP TO 60 MPH.
- BELOW AVERAGE TEMPERATURES, ALONG WITH PERIODIC ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS, ARE EXPECTED THE REST OF
THE WORK WEEK WITH HIGHS MOSTLY IN THE 70S AND LOWS MOSTLY IN
THE 50S.
UPDATE
ISSUED AT 1000 PM CDT TUE JUL 29 2025
AN INVERTED SURFACE TROUGH, DRAPED ALONG AN AXIS FROM
SOUTHWESTERN TO NORTH CENTRAL NORTH DAKOTA, CONTINUES TO PROMOTE
SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS OVER
PORTIONS OF THE FORECAST AREA THIS EVENING. MODERATE INSTABILITY
WITH MLCAPE VALUES AROUND 1000 J/KG AND SHEAR AROUND 30 KNOTS
LINGERS ACROSS SOUTHWESTERN NORTH DAKOTA THIS EVENING, ALLOWING
FOR A STRONGER STORM OR TWO TO REMAIN POSSIBLE THROUGH THE EARLY
EVENING. MORE GENERAL SHOWERS AND ISOLATED STORMS ARE THEN
ANTICIPATED TO LINGER AS THE INCITING SURFACE BOUNDARY CONTINUES
TO SINK SOUTHWARD THROUGH TOMORROW MORNING. REGARDING UPDATES,
HAVE MODIFIED POPS SLIGHTLY TO ACCOUNT FOR SHOWERS LINGERING A
LITTLE FURTHER NORTH THAN PREVIOUSLY FORECAST. OTHERWISE, THE
FORECAST REMAINS BROADLY ON TRACK.
UPDATE ISSUED AT 650 PM CDT TUE JUL 29 2025
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE FOUND OVER
PORTIONS OF WESTERN AND NORTH CENTRAL NORTH DAKOTA AT THE TIME
OF THIS EARLY EVENING UPDATE. AN NE-SW ORIENTATED OUTFLOW
BOUNDARY CROSSING THE THE SOUTHEAST HAS PROMOTED THE
DEVELOPMENT OF A STRONG TO SEVERE THUNDERSTORM THAT HAS BEEN
FOLLOWING THE MISSOURI RIVER OVER THE PAST FEW HOURS. WITH AN
INVERTED SURFACE TROUGH STARTING TO CROSS INTO SOUTHWESTERN
NORTH DAKOTA, WHERE THE BEST CONVECTIVE ENVIRONMENT IS FOUND,
THE DEVELOPMENT OF MORE STORMS IS ANTICIPATED THIS EVENING INTO
THE EARLY OVERNIGHT PERIOD. A FEW OF THESE STORMS COULD BECOME
STRONG TO SEVERE, WITH THE MAIN HAZARDS OF LARGE HAIL UP TO HALF
DOLLARS AND WIND GUSTS UP TO 60 MPH STILL POSSIBLE WITH ANY
SEVERE STORM THAT DOES DEVELOP. IN TERMS OF UPDATES, HAVE
BLENDED IN THE LATEST MODEL TRENDS INTO POPS, ACCOUNTING FOR THE
LINGERING AREA OF SHOWERS ALONG THE INTERNATIONAL BORDER, AND A
SLIGHT EASTWARD EXPANSION OF MEDIUM CHANCES ACROSS SOUTH
CENTRAL NORTH DAKOTA THIS EVENING AS THE AFOREMENTIONED OUTFLOW
BOUNDARY CONTINUES TO MOVE TO THE SOUTHEAST.
DISCUSSION
ISSUED AT 314 PM CDT TUE JUL 29 2025
THIS AFTERNOON, THE SYNOPTIC PATTERN WAS CHARACTERIZED BY A
STOUT UPPER HIGH OVER THE SOUTHERN PLAINS, WHILE RIDGING WAS
ATTEMPTING TO BUILD OVER THE WESTERN CONUS IN RESPONSE TO A DEEP
LOW OFF THE COAST OF BRITISH COLUMBIA. FLOW ACROSS NORTH DAKOTA
WAS ZONAL, WITH ANOTHER DEEP HUDSON BAY LOW TO THE NORTHEAST. AT
THE SURFACE, HIGH PRESSURE WAS CENTERED IN CENTRAL SASKATCHEWAN,
WITH A WEAK SURFACE TROUGH ANALYZED THROUGH CENTRAL AND EASTERN
MONTANA.
AS FLOW ALOFT TO OUR WEST BECOMES A BIT MORE AGITATED AND A
SHORTWAVE MOVES THROUGH THE REGION, FORCING FOR ASCENT BECOMES
BROAD BUT WEAK. A FEW ISOLATED THUNDERSTORMS ARE ALREADY ONGOING
ACROSS EASTERN MONTANA AND INTO NORTHWEST NORTH DAKOTA THIS
AFTERNOON, IN AN ENVIRONMENT WITH UP TO 1500 J/KG OF MOSTLY
UNCAPPED MLCAPE, MODESTLY STEEP LOW- AND MID-LEVEL LAPSE RATES,
AND BULK SHEAR ON THE ORDER OF 50 KNOTS. CAMS HAVE BEEN A BIT
INCONSISTENT REGARDING TIMING OF ANY STRONGER TO SEVERE STORMS,
BUT ARE MORE STEADY IN HIGHLIGHTING WESTERN NORTH DAKOTA AS THE
MOST LIKELY AREA FOR CONVECTION THIS AFTERNOON AND EVENING. WE
CONTINUE TO ADVERTISE ISOLATED SEVERE THUNDERSTORMS WITH THE
MAIN HAZARDS AS HAIL UP TO THE SIZE OF PING PONG BALLS AND WIND
GUSTS UP TO 60 MPH. LOW TO MEDIUM PRECIPITATION CHANCES CONTINUE
THIS EVENING, THROUGH THE NIGHT, AND INTO WEDNESDAY AFTERNOON,
SHRINKING TO BE FOCUSED ON THE SOUTHWEST PART OF THE STATE. SOME
NEAR SURFACE SMOKE IS POSSIBLE LATE TONIGHT THROUGH MUCH OF
WEDNESDAY, PRIMARILY ACROSS THE EAST AND SOUTH.
THE REMAINDER OF THE WORK WEEK IS RELATIVELY CONSISTENT,
FORECAST WISE, WITH NORTHWESTERLY FLOW DOMINATING AS THE UPPER
RIDGE SLOWLY DRIFTS OVER THE NORTHERN ROCKIES. HIGH TEMPERATURES
WILL REMAIN STEADILY IN THE 70S, AND LOWS IN THE 50S. CHANCES
FOR SHOWERS AND THUNDERSTORMS ARE ON AND OFF THROUGH THIS TIME,
WITH A FEW DIFFERENT SHORTWAVES MOVING THROUGH THE BROAD NORTHWEST
FLOW. CHANCES ARE HIGHEST IN THE SOUTHWEST PART OF THE STATE,
WITH THE BULK OF FAVORABLE FORCING SKIRTING BY NORTH DAKOTA.
NSSL AND CSU MACHINE LEARNING PROBABILITIES SHOW THE LIKELIHOOD
OF SEVERE WEATHER ACROSS THE ARE AS A WHOLE ARE QUITE LOW, WITH
THE ONLY AREA WITH ANY POTENTIAL THE SOUTHWEST PART OF THE
STATE.
THE UPPER RIDGE AXIS IS PROGGED TO EXTEND ACROSS THE FORECAST
AREA AND INTO THE SOUTHERN CANADIAN PRAIRIES TO START THE
WEEKEND, WITH TEMPERATURES SLOWLY WARMING BACK CLOSER TO NORMAL,
IN THE UPPER 70S TO MID 80S. WE CONTINUE THE SOMEWHAT ACTIVE
PATTERN, WITH DETERMINISTIC GUIDANCE SHOWING INSTABILITY
STARTING TO INCREASE ACROSS A LARGER PORTION OF THE STATE ON
SATURDAY AND SUNDAY. MORE OF THE SAME IS FAVORED FOR AT LEAST
THE BEGINNING OF NEXT WORK WEEK, WITH ABOVE NORMAL TEMPERATURES
FAVORED THROUGH THE FIRST WEEK OF AUGUST, AND NO INDICATIONS OF
A SIGNIFICANT DRY PATTERN COMING UP.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 1000 PM CDT TUE JUL 29 2025
VFR CEILINGS AND VISIBILITY IS ANTICIPATED AT MOST TERMINALS
THROUGHOUT THE 00Z TAF PERIOD. CHANCES FOR SHOWERS AND SCATTERED
THUNDERSTORMS INCREASES ACROSS SOUTHWEST AND SOUTH CENTRAL
NORTH DAKOTA THIS EVENING AND OVERNIGHT. WITH THIS UPDATE, HAVE
INCLUDED PROB30 GROUPS FOR -TSRA AT KDIK THIS EVENING AND
TOMORROW MORNING, AND A PROB30 GROUP FOR SHOWERS AT KBIS THIS
EVENING. CONFIDENCE IN SHOWERS OR STORMS ELSEWHERE REMAIN TOO
LOW TO INCLUDE WITH THIS UPDATE. HAVE INCLUDED MVFR CEILINGS AT
KDIK TOMORROW MORNING DUE TO THE COMPARABLE PERVASIVE CHANCES
FOR SHOWERS AND STORMS IN THE SOUTHWEST. OTHERWISE, WINDS ARE
ANTICIPATED TO DIMINISH THROUGH THE EVENING, BECOMING LIGHT AND
GENERALLY TURN TO THE EAST THROUGHOUT THE 00Z TAF PERIOD.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...ADAM
DISCUSSION...JONES
AVIATION...ADAM
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