161
FXUS63 KBIS 050005
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
705 PM CDT SUN MAY 4 2025
KEY MESSAGES
- CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE ACROSS MOST OF
WESTERN AND CENTRAL NORTH DAKOTA THROUGH THIS EVENING.
- GUSTY SOUTHERLY WINDS ACROSS WESTERN AND CENTRAL NORTH DAKOTA
THROUGH THIS EVENING, CONTINUING IN SOUTH CENTRAL AND EASTERN
NORTH DAKOTA ON MONDAY. STRONGER NORTHERLY WINDS IN NORTHWEST
NORTH DAKOTA ON MONDAY.
- ISOLATED SHOWERS AND THUNDERSTORMS COULD DEVELOP IN WESTERN
NORTH DAKOTA THIS EVENING. HIGHER CHANCES FOR SCATTERED
SHOWERS AND STORMS INCREASE MONDAY AFTERNOON THROUGH THE
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 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 703 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
SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE ACROSS WESTERN
NORTH DAKOTA THIS EVENING. 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 20 KTS THIS EVENING,
DECREASING SLIGHTLY OVERNIGHT AND TURNING TO THE SOUTHEAST IN
WESTERN NORTH DAKOTA. A COLD FRONT WILL MOVE INTO WESTERN NORTH
DAKOTA ON 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.
FIRE WEATHER
ISSUED AT 703 PM CDT SUN MAY 4 2025
RED FLAG WARNING REMAINS IN EFFECT FOR MOST OF WESTERN AND
CENTRAL NORTH DAKOTA. LAMOURE AND DICKEY COUNTIES REMAIN AT
NEAR-CRITICAL FIRE WEATHER CONDITIONS FOR TODAY GIVEN
UNCERTAINTY IN FUELS AS A GREENUP IS MORE APPARENT THERE, YET
UNCERTAIN IF THAT IS ENOUGH TO OVERCOME REMAINING TALL DEAD
GRASSES FROM LAST SEASON. SOUTH WINDS UP TO 30 MPH WITH GUSTS UP
TO 40 MPH REMAIN IN THE FORECAST THROUGH THIS EVENING.
EARLY EVENING RH VALUES REMAIN IN THE 15 TO 25 PERCENT RANGE,
BUT SHOULD BEGIN SLOWLY RISING BY SUNSET. ANYWHERE IN THE RED
FLAG WARNING COULD SEE RAPID GROWTH AND SPREAD OF WILDFIRES. THE
MOST CONCERNING AREAS WITHIN THE RED FLAG WARNING ARE IN
SOUTHWEST AND CENTRAL NORTH DAKOTA. THESE AREAS HAVE LOW LEVEL
LAPSE RATES OVER 8 C/KM OVERLAP WITH THE STRONGEST 850 MB LEVEL
WINDS ALOFT. FOR THOSE INTERESTED, MUCH OF THE NORTHERN PLAINS
IS NOW COVERED UNDER GOES EAST 19 MESO SECTOR 1 TO HELP MONITOR
FOR HOT SPOTS USING SATELLITE DATA.
TONIGHT, A STEADY SOUTHERLY WIND WILL LINGER THROUGH THE NIGHT
WITH RH RECOVERIES AROUND 50 TO 80 PERCENT. CHANCES FOR
PRECIPITATION MOVE ACROSS THE REGION FROM WEST TO EAST ON
MONDAY. THIS INCREASED MOISTURE MAY BE DELAYED ACROSS THE EAST,
AND WARM TEMPERATURES COULD ALLOW AFTERNOON RH VALUES TO DROP
INTO THE 20S. BREEZY SOUTHERLY WINDS ARE ALSO EXPECTED ACROSS
THE EAST ON MONDAY, WHILE WINDS BECOME STRONGER OUT OF THE
NORTH ACROSS WESTERN NORTH DAKOTA. A FEW THUNDERSTORMS ARE ALSO
POSSIBLE FOR MONDAY. THE COMBINATION OF LOWER HUMIDITY VALUES
AND BREEZY WINDS MAY RESULT IN NEAR-CRITICAL FIRE WEATHER
CONDITIONS MAINLY EAST OF HIGHWAY 83 THROUGH MONDAY AFTERNOON.
BREEZY NORTHERLY WINDS WITH WIDESPREAD SHOWER AND THUNDERSTORM
CHANCES ARE THEN EXPECTED FOR MONDAY NIGHT. COOLER TEMPERATURES,
IMPROVED HUMIDITY VALUES, AND SOME LINGERING BREEZY NORTHERLY
WINDS ARE THEN EXPECTED FOR TUESDAY. SOME SHOWERS MAY LINGER IN
THE WEST AS WELL ON TUESDAY.
BIS WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 9 PM CDT /8 PM MDT/ THIS EVENING FOR
NDZ001>005-009>013-017>023-025-031>037-040>047-050.
UPDATE...HOLLAN
DISCUSSION...ANGLIN
AVIATION...HOLLAN
FIRE WEATHER...ANGLIN/HOLLAN
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