829
FXUS63 KBIS 050241
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
941 PM CDT SUN MAY 4 2025
KEY MESSAGES
- NEAR-CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED ACROSS MUCH
OF CENTRAL NORTH DAKOTA ON MONDAY.
- WARM AND WINDY FOR MOST AREAS ON MONDAY. COOLER IN THE
NORTHWEST WITH STRONG NORTHERLY WINDS.
- ISOLATED SHOWERS AND THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA
THROUGH TONIGHT, THEN HIGHER CHANCES IN SOUTHWEST AND CENTRAL
NORTH DAKOTA MONDAY AFTERNOON AND EVENING.
- COOLER ON TUESDAY, WITH A FEW LINGERING SHOWERS IN THE
SOUTHWEST. THEN MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES AND
BREEZY CONDITIONS AT TIMES THROUGH THE END OF THE WEEK.
UPDATE
ISSUED AT 940 PM CDT SUN MAY 4 2025
THE RED FLAG WARNING WAS ALLOWED TO EXPIRE AT 9 PM CDT, AS FIRE
WEATHER CONDITIONS CONTINUE TO IMPROVE. THE MAIN CONCERN FOR THE
LATE EVENING HOURS IS A CORRIDOR OF SCATTERED SHOWERS AND
THUNDERSTORMS THAT WAS LOCATED FROM NEAR FORT UNION TO NORTHEAST
DIVIDE AND NORTHWEST BURKE COUNTIES AS OF 930 PM CDT. LESS THAN
AN HOUR EARLIER, A SMALLER CLUSTER OF STORMS HAD BECOME STRONG
JUST NORTH OF SIDNEY, MT. BUT A RAPID DECREASE IN INTENSITY HAS
BEEN OBSERVED THROUGH BOTH RADAR AND LIGHTNING DETECTION IN JUST
THE LAST 15 MINUTES. THE ENVIRONMENT SHOULD BECOME INCREASINGLY
UNSUPPORTIVE OF THUNDERSTORMS OVER THE NEXT FEW HOURS, BUT
ISOLATED TO SCATTERED SHOWERS WILL REMAIN POSSIBLE THROUGH THE
NIGHT, EXTENDING BACK INTO FAR SOUTHWEST NORTH DAKOTA.
UPDATE
ISSUED AT 607 PM CDT SUN MAY 4 2025
LATE AFTERNOON SATELLITE IMAGERY SHOWS AGITATED CUMULUS CLOUDS
BUILDING ALONG A SURFACE WIND SHIFT FROM NEAR GLENDIVE, MT TO
BELLE FOURCHE, SD. A FEW UPDRAFTS HAVE BEEN ABLE TO GROW INTO
THUNDERSTORMS, MAINLY SOUTH OF HIGHWAY 12. LATEST SPC
MESOANALYSIS SHOWS UP TO 1000 J/KG SBCAPE BUT ONLY 500 J/KG
MLCAPE IN SOUTHWEST NORTH DAKOTA. EFFECTIVE BULK SHEAR IS ALSO
ONLY AROUND 20-25 KTS. STORMS ARE NOT EXPECTED TO BECOME SEVERE,
BUT THE STRONGLY MIXED BOUNDARY LAYER COULD PROMOTE CONVECTIVE
WIND GUSTS ENHANCED BEYOND THE BACKGROUND SYNOPTIC WINDS.
FURTHER NORTH, A LESS-AGITATED CUMULUS FIELD IS FILLING IN OVER
NORTHWEST NORTH DAKOTA. THIS COULD EVENTUALLY LEAD TO A FEW
SHOWERS AND PERHAPS A WEAK THUNDERSTORM, BUT BOTH CAPE AND SHEAR
ARE MUCH LOWER IN THAT PART OF THE STATE.
DISCUSSION
ISSUED AT 325 PM CDT SUN MAY 4 2025
DEVELOPING SURFACE LOW IN EASTERN MT AND EXITING HIGH PRESSURE
TO OUR EAST WILL CONTINUE TO BRING A WARM, DRY, AND WINDY FLOW
THROUGH THIS EVENING. ISOLATED ADVISORY WINDS HAVE BEEN NOTED
ALREADY THIS AFTERNOON, ALTHOUGH ARE NOT WIDESPREAD ENOUGH FOR A
HIGHLIGHT AT THIS TIME. THE BIGGER CONCERN IS WIDESPREAD
CRITICAL FIRE WEATHER CONDITIONS EXPECTED THROUGH THIS EVENING.
A RED FLAG WARNING CONTINUES FOR MOST OF THE CWA. SEE THE FIRE
WEATHER DISCUSSION BELOW FOR MORE DETAILS. THIS EVENING THROUGH
TONIGHT, A BOUNDARY OF UP TO 1000 J/KG MUCAPE STILL LOOKS TO SET
UP IN THE WEST. SHEAR IN THIS AREA LOOKS OVERALL LOW. HOWEVER,
WITH THE LOW APPROACHING AND ISOLATED THUNDERSTORM IS POSSIBLE
THROUGH TONIGHT. SPC HAS ALSO ADDED IN GENERAL THUNDER FOR THIS
THREAT. THE CHANCE FOR SEVERE WEATHER IS OVERALL LOW. THE STRONG
LOW LEVEL JET ALOFT AND INVERTED V SOUNDING COULD BRING A
MAINLY SUB SEVERE WIND THREAT WITH ANY STORMS THAT CAN DEVELOP.
LOWS TONIGHT WILL BE MILD AND MAINLY IN THE 50S. LOW AND
ASSOCIATED COLD FRONT IS STILL EXPECTED TO MOVE THROUGH MONDAY,
ALTHOUGH PRECIPITATION AND COLD FRONT TIMING MAY BE SLIGHTLY
DELAYED. BECAUSE OF THIS, WARM, DRY, AND BREEZY CONDITIONS MAY
LINGER ACROSS THE EAST AND PERHAPS BRING SOME NEAR CRITICAL FIRE
WEATHER CONDITIONS. MEANWHILE, IN THE WEST COLD FRONT PASSAGE
WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS. STRONG NORTH
WINDS BEHIND THE FRONT COULD ALSO BE FOUND, AND PERHAPS BE AT
ADVISORY LEVELS. AS THE FRONT ENTERS CENTRAL NORTH DAKOTA LATER
IN THE DAY, MODEST MUCAPE AND SHEAR WILL BE FOUND. THERE IS SOME
CAPPING CONCERNS AND THE BETTER SHEAR IS NOT FULLY ALIGNED WITH
THE HIGHEST INSTABILITY. SPC HAS MAINTAINED A GENERAL RISK FOR
THUNDERSTORMS ON MONDAY. OF NOTE ARE LOW CHANCES FOR SEVERE HAIL
IN THE CSU-MLP GUIDANCE. IF SHEAR AND INSTABILITY CAN BETTER
ALIGN, THEN PERHAPS AN ISOLATED STRONG TO SEVERE STORM IS
POSSIBLE, ALTHOUGH CONFIDENCE IS NOT HIGH ENOUGH TO MESSAGE
SEVERE WEATHER AT THIS POINT. HIGHS ON MONDAY WILL SEE A WIDE
RANGE DUE TO THE MENTIONED COLD FRONT. LOOK FOR HIGHS NEAR 60 IN
THE NORTHWEST TO NEAR 80 IN THE SOUTHEAST. WIDESPREAD SHOWERS
WITH A FEW THUNDERSTORMS ARE THEN EXPECTED FOR MONDAY NIGHT.
MOST AREAS WILL SEE WINDS BECOME NORTHERLY AND BECOME BREEZY.
LOWS WILL DIP INTO THE UPPER 30S TO UPPER 40S.
POST FRONTAL CONDITIONS TO BE FOUND ON TUESDAY. LINGERING
SHOWERS COULD BE FOUND THROUGH THE DAY. BREEZY NORTHEAST WINDS
COULD BE FOUND CENTRAL AND EAST, ALTHOUGH COOLER TEMPERATURES IN
THE UPPER 50S TO UPPER 60S WILL BRING IMPROVED HUMIDITY VALUES.
WINDS AND PRECIPITATION CHANCES WILL DIMINISH TUESDAY NIGHT.
OVERNIGHT LOWS COULD BE QUITE COOL AND IN THE 30S TO LOWER 40S
ACROSS MUCH OF THE AREA. RIDGE TO FLAT RIDGING THEN FORECAST FOR
THE MID TO LATE WEEK PERIOD. THIS BRINGS WARMING TEMPERATURES
BACK INTO THE 70S TO PERHAPS LOWER 80S. BREEZY WINDS AT TIMES
MAY ALSO ACCOMPANY THIS PATTERN THROUGH THE END OF THE WEEK.
HUMIDITY VALUES COULD LOWER AGAIN DURING THIS TIME PERIOD, AND
MAY NEED TO BE MONITORED FOR THE RETURN OF FIRE WEATHER
CONCERNS. CHANCES FOR PRECIPITATION ARE LIMITED RIGHT NOW. THERE
COULD BE A WEAK WAVE IN THE FLOW THURSDAY EVENING INTO FRIDAY.
NBM PUTTING A SLIGHT CHANCE OF SHOWERS AS A RESULT DURING THIS
TIME PERIOD.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 940 PM CDT SUN MAY 4 2025
VFR CONDITIONS ARE EXPECTED FOR MOST AREAS THROUGH THE FORECAST
PERIOD. ONE EXCEPTION IS IN NORTHWEST NORTH DAKOTA WHERE MVFR
CEILINGS ARE FORECAST TO MOVE IN MONDAY AFTERNOON. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE ACROSS
WESTERN NORTH DAKOTA THIS EVENING INTO THE OVERNIGHT HOURS.
THEN ON MONDAY, NORTHWEST NORTH DAKOTA COULD SEE LIGHT RAIN
SHOWERS RETURN IN THE AFTERNOON, WITH SCATTERED SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS NORTHWEST AND CENTRAL NORTH
DAKOTA LATER IN THE AFTERNOON. CONFIDENCE IS HIGH ENOUGH TO
INTRODUCE A PROB30 FOR TSRA AT KDIK WITH THIS SET OF TAFS, WITH
KBIS AND KMOT TO SEE HIGHER ODDS FOR SHOWERS AND STORMS MONDAY
EVENING. ANY STORM THAT MOVES OVER A TERMINAL THROUGHOUT THE
FORECAST PERIOD WILL BE CAPABLE OF BRIEF PERIODS OF MVFR/IFR
VISIBILITY RESTRICTIONS AND ERRATIC, GUSTY WINDS.
SOUTHERLY WINDS WILL PERSIST AROUND 10-20 KTS THROUGH THE NIGHT.
A COLD FRONT WILL MOVE INTO WESTERN NORTH DAKOTA EARLY MONDAY,
REACHING KDIK TO KMOT BY THE END OF THE FORECAST PERIOD. AHEAD
OF THE FRONT, SOUTHERLY WINDS AROUND 15-25 KTS WILL PREVAIL ON
MONDAY. BEHIND THE FRONT, WINDS WILL SHIFT TO THE NORTH AROUND
15-25 KTS, BUT STRONGER SPEEDS WITH GUSTS UP TO 40 KTS ARE
EXPECTED IN NORTHWEST NORTH DAKOTA MONDAY AFTERNOON. LASTLY, LOW
LEVEL WIND SHEAR WILL IMPACT SOUTHWEST AND CENTRAL NORTH DAKOTA
LATE THIS EVENING INTO EARLY MONDAY MORNING.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...HOLLAN
DISCUSSION...ANGLIN
AVIATION...HOLLAN
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