436
FXUS63 KBIS 101420
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
920 AM CDT SAT MAY 10 2025
KEY MESSAGES
- UNSEASONABLY HOT THIS WEEKEND INTO EARLY NEXT WEEK, WITH
WIDESPREAD HIGHS IN THE 90S. SEVERAL MAXIMUM TEMPERATURE
RECORDS COULD BE BROKEN.
- CRITICAL FIRE WEATHER CONDITIONS EXPECTED ACROSS WESTERN AND
MOST OF CENTRAL NORTH DAKOTA LATE THIS MORNING THROUGH THE
EVENING.
- WINDY ACROSS CENTRAL AND EASTERN NORTH DAKOTA SUNDAY AND
MONDAY, WITH NEAR-CRITICAL TO CRITICAL FIRE WEATHER
CONDITIONS.
- THERE IS A 20 PERCENT CHANCE OF THUNDERSTORMS ACROSS WESTERN
AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA SUNDAY EVENING. A
FEW STORMS COULD BECOME STRONG TO MARGINALLY SEVERE.
- HIGHER CHANCES FOR RAIN AND MUCH COOLER TEMPERATURES RETURN
FOR THE SECOND HALF OF NEXT WEEK.
UPDATE
ISSUED AT 921 AM CDT SAT MAY 10 2025
WINDS ARE ALREADY QUITE BREEZY ACROSS THE FORECAST AREA AS A
SURFACE LOW TO OUR NORTHWEST DEEPENS, AND LOW-LEVEL WARM AIR
ADVECTION SPREADS ACROSS THE AREA. THE SHOWER ACTIVITY THAT WAS
MOVING THROUGH EARLIER HAVE EXITED TO OUR EAST, WITH A FEW NDAWN
STATIONS REPORTING A HUNDRETH OR TWO OF RAIN. NO BIG CHANGES
NEEDED TO THE FORECAST WITH THIS UPDATE, WITH A HOT, DRY, AND
BREEZY DAY EXPECTED.
UPDATE
ISSUED AT 623 AM CDT SAT MAY 10 2025
SHOWERS HAVE BECOME A BIT MORE WIDESPREAD THAN EARLIER FORECAST,
GENERALLY EAST OF THE HIGHWAY 83 CORRIDOR. WE HAVE EVEN SEEN A
FEW LIGHTNING STRIKES HERE AND THERE. THUS, WE EXPANDED AREA OF
ISOLATED SHOWERS FOR THE NEXT FEW HOURS AND ADDED MENTION OF
ISOLATED THUNDER AS WELL. OTHERWISE, NO MAJOR CHANGES WERE
NEEDED FOR THIS UPDATE OTHER THAN TO BLEND IN THE LATEST
OBSERVATIONS.
DISCUSSION
ISSUED AT 316 AM CDT SAT MAY 10 2025
FIRE WEATHER CONCERNS ARE THE BIG STORY OVER THE NEXT FEW DAYS
ACROSS WESTERN AND CENTRAL NORTH DAKOTA. A RED FLAG WARNING
REMAINS IN EFFECT FOR WESTERN AND MOST OF CENTRAL NORTH DAKOTA
LATE THIS MORNING THROUGH THIS EVENING. THE START TIME WAS MOVED
UP AN HOUR TO 16Z AND SHERIDAN, WELLS, AND FOSTER COUNTIES HAVE
BEEN ADDED FOR THIS FORECAST PACKAGE. NEAR-CRITICAL FIRE
WEATHER CONDITIONS ARE LIKELY ACROSS ALL COUNTIES NOT IN THE
WARNING (PORTIONS OF THE SOUTH CENTRAL AND SOUTHERN PORTIONS OF
THE JAMES RIVER VALLEY ON THE NORTH DAKOTA SIDE). MORE NEAR-
CRITICAL TO CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED SUNDAY
AND MONDAY. FOR SPECIFICS REGARDING THE FIRE WEATHER CONCERNS,
PLEASE SEE THE FIRE WEATHER DISCUSSION BELOW. ASIDE FROM FIRE
WEATHER CONCERNS, THERE IS A PLETHORA OF WEATHER TOPICS TO DIG
INTO FOR THIS FORECAST PACKAGE SO LET'S TRY TO WORK THROUGH IT
ALL.
THE PATTERN:
AN EXPANSIVE MID/UPPER LEVEL WESTERN CONUS RIDGE CONTINUES TO BE
THE DOMINANT FEATURE DRIVING THE WEATHER PATTERN THIS WEEKEND.
THE RIDGE AXIS WILL NUDGE INTO WESTERN NORTH DAKOTA THIS
AFTERNOON AS THE THERMAL RIDGE ALSO STARTS TO MOVE INTO THE
WEST. HIGHS TODAY WILL BE QUITE A BIT WARMER THAN YESTERDAY,
FORECAST TO RANGE FROM THE LOW TO MID 80S EAST TO THE LOWER 90S
WEST. ALTHOUGH, IT WOULD NOT BE SURPRISING TO SEE SOME MID 90S
ACROSS THE WEST BEFORE THE AFTERNOON IS OVER. A DISTURBANCE
RIDING OVER THE CREST OF THE RIDGE WILL BRING A LOW CHANCE (~20
PERCENT) OF SHOWERS TO THE TURTLE MOUNTAINS/DEVILS LAKE BASIN
LATER THIS MORNING. A LOW CHANCE OF A THUNDERSTORM MAY NOT BE
OUT OF THE QUESTION IN THE AFTERNOON EITHER AS A COUPLE OF CAMS
ARE DEVELOPING SOME ISOLATED ACTIVITY. FORECAST HEIGHT
TENDENCIES LEND PLENTY OF DOUBT TO THIS AFTERNOON POTENTIAL,
HOWEVER.
TEMPERATURES:
THE CORE OF THE THERMAL RIDGE MOVES INTO ALL OF WESTERN AND
CENTRAL NORTH DAKOTA SUNDAY AND MONDAY, BRINGING UNSEASONABLY
HOT CONDITIONS TO THE ENTIRE AREA WITH WIDESPREAD HIGHS IN THE
90S. A FEW READINGS IN THE TRIPLE DIGITS CONTINUE TO LOOK MORE
AND MORE LIKELY AS EVEN THE NBM 50TH PERCENTILE IS SHOWING HIGHS
REACHING 100 ACROSS PORTIONS OF THE NORTH CENTRAL EACH
AFTERNOON. GIVEN CONSISTENT AND WIDESPREAD EXTREME FORECAST
INDEX (EFI) READINGS OF 1.0, HIGHS ARE LIKELY TO TREND TOWARDS
THE HIGHER NBM PERCENTILES. ADDITIONALLY, THE NAEFS CONTINUES TO
ADVERTISE 850MB TEMPERATURES IN THE 99.5TH PERCENTILE OR
GREATER FOR THIS TIME OF YEAR ACROSS MOST OF WESTERN AND CENTRAL
NORTH DAKOTA BOTH DAYS, WHICH LENDS CONFIDENCE TO HIGHLY
ANOMALOUS TEMPERATURES. SEVERAL HIGH TEMPERATURE RECORDS ARE
LIKELY TO BE BROKEN SUNDAY AND MONDAY. A COLD FRONT WILL MOVE
INTO THE WEST OVERNIGHT MONDAY/TUESDAY MORNING, LEADING TO
COOLER HIGHS ACROSS THE WEST (IT WILL REMAIN QUITE WARM EAST).
HIGHS ON TUESDAY SHOULD RANGE FROM THE MID 70S WEST TO THE LOWER
90S SOUTHEAST. WIDESPREAD MEDIUM TO HIGH PRECIPITATION CHANCES
(40 TO 80 PERCENT) THEN MOVE BACK INTO THE FORECAST TUESDAY
EVENING THROUGH AT LEAST THURSDAY NIGHT WHICH WILL COINCIDE
WITH MUCH COOLER TEMPERATURES. HIGHS ON WEDNESDAY WILL RANGE
FROM THE LOWER 60S NORTHWEST, TO THE LOW TO MID 80S SOUTHEAST.
THURSDAY'S HIGHS WILL RANGE FROM THE MID 50S NORTHWEST TO THE
THE LOWER 70S SOUTHEAST. ON FRIDAY, WE COULD THEN SEE HIGHS
MAINLY IN THE 50S EVERYWHERE.
THUNDERSTORMS AND PRECIPITATION:
ON SUNDAY, WE TRANSITION BACK INTO SOUTHWEST FLOW ALOFT AND WE
SHOULD SEE SOME HEIGHT FALLS APPROACH THE WEST AS AN INITIAL
IMPULSE EJECTS FROM A PACIFIC NORTHWEST TROUGH MAKING IT'S WAY
ON SHORE. THIS SHOULD LEAD SO SOME LOW CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS THE WEST WITH THE BEST CHANCES NORTHWEST.
NAM AND GFS SOUNDINGS SUGGEST THAT WE COULD SEE SOME MUCAPE
AROUND 500 J/KG AND SOME DEEP LAYER SHEAR IN THE 30 TO 40 KNOT
RANGE. IN THE WAKE OF STRONG DAYTIME HEATING AND HIGH CLOUD
BASES, A FEW MARGINALLY SEVERE WIND GUSTS WILL BE POSSIBLE WITH
THE STRONGEST STORMS AND WOULD BE THE PRIMARY THREAT. HOWEVER,
SOME SMALL HAIL COULD ALSO BE POSSIBLE. STORM COVERAGE WILL
LIKELY BE LIMITED AND ACTIVITY SHOULD DIMINISH AFTER MIDNIGHT
OR SO.
THE STORY WILL BE SIMILAR ON MONDAY AS THE WESTERN TROUGH
CONTINUES TO NUDGE CLOSER. HOWEVER, MODELS HAVE BACKED OFF A
BIT WITH REGARDS TO THUNDERSTORM POTENTIAL MONDAY EVENING AS
MOST OF THE FORCING WILL END UP OVER THE CANADIAN PRAIRIES.
WHILE THE NBM IS STILL PAINTING SOME LOW CHANCES FOR SHOWERS
ACROSS THE WEST AND NORTH CENTRAL, THUNDERSTORM CHANCES HAVE
DIMINISHED.
BY TUESDAY EVENING, WE SHOULD SEE SOME STORMS DEVELOP ALONG AND
BEHIND THE EASTWARD MOVING COLD FRONT. SOME MODELS ARE SHOWING
STRONGER INSTABILITY ALONG AND EAST OF THIS BOUNDARY BUT IT IS
DISPLACED FROM THE STRONGEST SHEAR. STILL, A STRONGER STORM OR
TWO IS NOT OUT OF THE QUESTION GIVEN THE INSTABILITY FORECAST TO
BE IN PLACE. WEDNESDAY COULD BE THE DAY TO WATCH FOR SOME MORE
WIDESPREAD STRONGER STORMS AS THE CORE OF THE TROUGH
APPROACHES, ALTHOUGH IT IS STILL QUITE A WAYS OUT. MODELS
SUGGEST SOME CAPE VALUES AROUND 1000 J/KG OVERLAPPING DEEP LAYER
SHEAR IN THE 35 TO 50 KNOT RANGE. THAT BEING SAID, WIDESPREAD
CLOUD COVER EARLY IN THE DAY AND THEN WIDESPREAD SHOWERS AND
STORMS LATE IN THE DAY COULD END UP LIMITING INSTABILITY SO
FUTURE TRENDS WILL HAVE TO BE MONITORED CLOSELY. AN UPPER LOW
THEN CLOSES OFF AT THE BASE OF THE TROUGH AND MOVES THROUGH THE
NORTHERN PLAINS THURSDAY AND FRIDAY, KEEPING MEDIUM TO HIGH
PRECIPITATION CHANCES IN THE FORECAST. THE LATEST NBM IS SHOWING
A 60 TO 80 PERCENT CHANCE FOR AT LEAST A HALF INCH OF RAIN OVER
ALL OF WESTERN AND CENTRAL NORTH DAKOTA FOR THE SECOND HALF OF
THE WEEK. THUS, THERE IS GROWING CERTAINTY THAT THE PATTERN
SHOULD BRING WIDESPREAD BENEFICIAL RAINS TO MOST OF WESTERN AND
CENTRAL NORTH DAKOTA. WITH THE CONVECTIVE NATURE OF THIS SYSTEM,
HOWEVER, SOME AREAS MAY SEE LESS AND SOME MAY SEE QUITE A BIT
MORE.
FINALLY, THIS PATTERN WILL BE CONDUCIVE TO PERIODIC BREEZY TO
WINDY CONDITIONS ALMOST DAILY. FUTURE WIND HEADLINES ARE NOT
OUT OF THE QUESTION FOR AREAS IN AND AROUND THE JAMES RIVER
VALLEY ON SUNDAY AND MONDAY.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 623 AM CDT SAT MAY 10 2025
NEAR SURFACE SMOKE HAS DRIFTED FROM CENTRAL INTO WESTERN NORTH
DAKOTA. OVER THE NEXT FEW HOURS, LOW VFR OR MARGINAL MVFR
VISIBILITIES WILL BE POSSIBLE AT KXWA AND/OR KDIK BEFORE THE
SMOKE PLUME DIMINISHES. ISOLATED SHOWERS HAVE ALSO DEVELOPED
THIS MORNING IN THE VICINITY OF THE DEVILS LAKE BASIN AND JAMES
RIVER VALLEY. THE MOST LIKELY TERMINAL TO SEE A BRIEF SHOWER
WOULD BE KJMS OVER THE NEXT HOUR OR TWO. OTHERWISE, VFR
CONDITIONS ARE EXPECTED. SOUTHERLY WINDS WILL BE ON THE INCREASE
THROUGH THE DAY WITH GUSTS UP TO 45 POSSIBLE IN THE AFTERNOON.
IT WILL REMAIN BREEZY OVERNIGHT.
FIRE WEATHER
ISSUED AT 316 AM CDT SAT MAY 10 2025
FIRE WEATHER CONCERNS CONTINUE TO GROW OVER THE NEXT FEW DAYS AS
ANOMALOUS HEAT, A VERY DRY ATMOSPHERE, AND STRONG WINDS WILL
CONTRIBUTE TO PERIODIC NEAR-CRITICAL TO CRITICAL FIRE WEATHER
CONDITIONS TODAY THROUGH MONDAY.
A RED FLAG WARNING IS IN EFFECT FROM 16Z THIS MORNING UNTIL 02Z
THIS EVENING FOR ALL OF WESTERN AND MOST OF CENTRAL NORTH DAKOTA.
HUMIDITY COULD DIP INTO THE 10 TO 15 PERCENT RANGE ACROSS
PORTIONS OF THE WEST THIS AFTERNOON AND IN THE 15 TO 20 PERCENT
RANGE MOST ELSEWHERE. A TIGHTENING PRESSURE GRADIENT AND STEEP
LOW LEVEL LAPSE RATES WILL LEAD TO INCREASING SOUTHERLY WINDS.
THE STRONGEST SUSTAINED WINDS WILL LIKELY BE ALONG AND EAST OF
THE HIGHWAY 83 CORRIDOR (UP TO 30 MPH) BUT READINGS UP TO 20
MPH WILL BE POSSIBLE ACROSS ALL OF WESTERN AND CENTRAL NORTH
DAKOTA. GUSTS IN THE 35 TO 45 MPH RANGE WILL ALSO BE POSSIBLE.
FOR SOME AREAS ACROSS THE SOUTH CENTRAL AND JAMES RIVER VALLEY,
GREENING FUELS MAY NOT BE AS CONDUCIVE TO RAPID FIRE SPREAD SO
WE WILL ADVERTISE THESE AREAS AS NEAR-CRITICAL IN THE HAZARDOUS
WEATHER OUTLOOK (HWO) FOR NOW.
MORE NEAR-CRITICAL TO CRITICAL FIRE WEATHER CONDITIONS ARE
POSSIBLE ON SUNDAY AND MONDAY GIVEN HOT TEMPERATURES AND A DRY
ATMOSPHERE. MINIMUM HUMIDITY EACH DAY IS FORECAST TO FALL INTO
THE 10 TO 20 PERCENT RANGE ACROSS ALL OF WESTERN AND CENTRAL
NORTH DAKOTA. STRONG SOUTHERLY WINDS ARE FORECAST ACROSS MUCH
OF THE SOUTH CENTRAL, JAMES RIVER VALLEY, AND INTO THE GREATER
DEVILS LAKE BASIN. UNCERTAINTY REGARDING FUELS REMAIN, BUT
FUTURE RED FLAG WARNINGS WILL LIKELY BE NEEDED AFTER WE GET PAST
TODAY'S THREAT.
A COLD FRONT MOVES THROUGH ON TUESDAY PROVIDING SOME RELIEF TO
THE WEST BUT WE COULD SEE ONE MORE ROUND OF AT LEAST NEAR-
CRITICAL CONDITIONS ACROSS THE SOUTHEAST DURING THE AFTERNOON.
WIDESPREAD WETTING RAINS ARE THEN LIKELY ACROSS ALL OF WESTERN
AND CENTRAL NORTH DAKOTA TUESDAY EVENING THROUGH AT LEAST
THURSDAY NIGHT.
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>034-040>045.
UPDATE...JONES
DISCUSSION...ZH
AVIATION...ZH
FIRE WEATHER...ZH
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