733
FXUS63 KBIS 080859
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
359 AM CDT WED JUL 8 2026
KEY MESSAGES
- COOLER TEMPERATURES REMAIN TODAY, FOLLOWED BY A STRONG
WARMING TREND THROUGH THE WEEKEND.
- ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THURSDAY AFTERNOON
INTO THURSDAY EVENING.
- VERY HOT THIS WEEKEND AND EARLY NEXT WEEK, WITH DAILY HIGH
TEMPERATURES AND MAXIMUM HEAT INDICES AROUND 95 TO 105.
DISCUSSION
ISSUED AT 339 AM CDT WED JUL 8 2026
A BROAD QUASI-ZONAL UPPER LEVEL FLOW WILL CONTINUE OVER THE
REGION THROUGH THE REMAINDER OF THE WORKWEEK, FOLLOWED BY
SIGNIFICANT UPPER LEVEL RIDGING OVER A LARGE PORTION OF THE
WESTERN AND CENTRAL CONUS. THIS COULD BRING A SIGNIFICANT
PROLONGED HEATWAVE TO WESTERN AND CENTRAL ND THIS WEEKEND INTO
EARLY NEXT WEEK.
CURRENTLY, THE LATEST SATELLITE IMAGERY SHOW A NUMBER OF WAVES
MOVING THROUGH THE BROAD UPPER LEVEL FLOW. LATEST RADAR SHOWS AN
AREA OF ISOLATED SHOWERS SITUATED OVER NORTHWEST ND. PATCHES OF
LOW STRATUS/FOG HAVE BEEN NOTED UNDER BREAKS OF HIGH LEVEL
CIRRUS, BUT AS OF YET NOTHING WIDESPREAD. AS WE HEAD INTO THE
EARLY MORNING HOURS GUIDANCE SUGGESTS, AND IT SEEMS REASONABLE,
GIVEN THE LOW T/TD SPREADS WE WILL SEE AN INCREASE IN STRATUS
AND FOG. GUIDANCE DOES FAVOR WESTERN AND SOUTHERN PORTIONS OF
THE FORECAST AREA.
FOR TODAY, FORECAST SOUNDINGS SUGGEST INSTABILITY WILL REMAIN
WEAK THIS MORNING. HOWEVER WITH AN APPROACHING SHORTWAVE
CURRENTLY INDICATED OVER EASTERN MONTANA, THERE MAY BE ENOUGH
FORCING TO KEEP A MENTION OF SHOWERS IN THE FORECAST. SOUNDINGS
DRY OUT THIS AFTERNOON AND MOSTLY DRY CONDITIONS ARE EXPECTED.
AFTERNOON CONVECTION OFF THE HIGHER TERRAIN IN WYOMING AND
SOUTHEAST MONTANA SHOULD REMAIN SOUTH AND EAST OF THE FORECAST
AREA LATER TODAY, BUT AN EVENING THUNDERSTORM CAN NOT BE RULED
OUT IN THE FAR SOUTHWEST. ANOTHER WAVE TRACKING ALONG THE
INTERNATIONAL BORDER MAY FIRE CONVECTION OVER CENTRAL MONTANA,
AND IF IT HOLDS TOGETHER COULD MOVE INTO FAR WESTERN ND TOWARDS
DAYBREAK THURSDAY. THE SEVERE THREAT BY THIS TIME WOULD BE LOW.
ON THURSDAY, THE AFOREMENTIONED WAVE TRACKS ACROSS THE STATE AND
A SURFACE TROUGH LINGERS OVER THE AREA. IT WILL BECOME VERY
UNSTABLE OVER WESTERN ND THURSDAY AFTERNOON WITH RAP FORECAST
MLCAPE VALUES AROUND 3000 J/KG. BULK SHEAR IS MARGINAL, RANGING
FROM 25 TO 35 KNOTS. FORCING FOR ASCENT WILL BE MODEST WITH ONLY
WEAK IMPULSES MOVING THROUGH A SLOWLY BUILDING RIDGE. IF THERE
IS ENOUGH FORCING TO OVERCOME SOME LOW LEVEL CAPPING, ISOLATED
STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE. SPC HAS
MAINTAINED A MARGINAL RISK (LEVEL 1 OUT OF 5) FOR SEVERE STORMS
ACROSS MOST OF THE FORECAST AREA THURSDAY. SHEAR VECTORS ARE NOT
COMPLETELY PERPENDICULAR TO THE SURFACE BOUNDARY BUT ENOUGH SO
THAT A SUPERCELL THUNDERSTORM CAN'T BE RULED OUT. THE MAIN
THREATS THURSDAY AFTERNOON AND EVENING WOULD BE LARGE HAIL TO
THE SIZE OF GOLF BALLS AND 60 MPH WINDS.
AFTER THURSDAY, ATTENTION SHIFTS TO THE POTENTIAL FOR A
PROLONGED HEAT THREAT THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK. FRIDAY WILL SEE DAYTIME HIGHS CLIMB INTO THE UPPER 80S TO
MID 90S, BUT THE MOST IMPACTFUL HEAT WILL BE OVER THE WEEKEND
AND EARLY NEXT WEEK. DAYTIME HIGHS OF 90 TO 100 ON SATURDAY, AND
95 TO 105 SUNDAY MAY NECESSITATE THE NEED FOR A LONG TERM HEAT
HAZARD, ESPECIALLY SINCE OVERNIGHT LOW TEMPERATURES REMAIN AT
OR ABOVE THE 70 DEGREE MARK. AT THIS TIME, SUNDAY LOOKS TO BE
THE MOST OPPRESSIVE DAY WITH HEAT INDICES ABOVE 100 DEGREES
ACROSS MOST OF THE FORECAST AREA, AND UP TO 108 DEGREES IN A FEW
AREAS. HOWEVER IF YOU CONSIDER THE HEATRISK AND WBGT, A CASE
COULD BE MADE FOR A LONG TERM HAZARD ENCOMPASSING SATURDAY
THROUGH MONDAY, GIVEN THE WARM OVERNIGHT LOWS. WE STILL HAVE A
WHILE TO PONDER, BUT IF CURRENT FORECAST TRENDS HOLD, IT WILL
DEFINITELY BE A VERY HOT WEEKEND. WITH A LOT OF OUTDOOR EVENTS
GOING ON, WE WILL DEFINITELY BE INCREASING OUR HEAT RELATED
MESSAGING.
THE OPPRESSIVE HEAT SHOULD LIMIT THUNDERSTORM ACTIVITY OVER THE
WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1155 PM CDT TUE JUL 7 2026
HIGH PRESSURE WILL BUILD OVER THE FORECAST AREA TONIGHT BEHIND
EXITING SHOWERS AND THUNDERSTORMS. WIDESPREAD LOW STRATUS AND
FOG ARE POSSIBLE OVER MUCH OF THE FORECAST AREA TONIGHT WITH
WESTERN AND SOUTHERN AREAS CURRENTLY FAVORED. MVFR TO IFR
VISIBILITIES AND CEILINGS ARE EXPECTED WHERE STRATUS/FOG DEVELOP
WITH LIFR CONDITIONS POSSIBLE. LOW STRATUS WILL LIFT BY MIDDAY
WITH VFR CONDITIONS EXPECTED THEREAFTER. GENERALLY LIGHT
EASTERLY FLOW THROUGH THE TAF PERIOD.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...TWH
AVIATION...TWH
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