445
FXUS63 KBIS 021131
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
631 AM CDT FRI JUN 2 2023
UPDATE
ISSUED AT 604 AM CDT FRI JUN 2 2023
CONVECTION HAS ENDED/MOVED OUT OF THE FORECAST AREA THIS MORNING.
A STRAY SPRINKLE OR SHOWER IS POSSIBLE THIS MORNING IN THE
NORTHWEST. FOR THE MOST PART LATEST CAMS HOLD OFF ON CONVECTION
DEVELOPING UNTIL AROUND 18 UTC, WHICH IS CONSISTENT WITH OUR
CURRENT FORECAST. NO CHANGES NEED WITH THE MORNING UPDATE.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 216 AM CDT FRI JUN 2 2023
ISOLATED TO SCATTERED CONVECTION IS EXPECTED AGAIN TODAY.
CURRENTLY, SURFACE LOW PRESSURE WAS LOCATED OVER EASTERN MONTANA
WITH A MOIST SOUTHEAST FLOW OVER THE FORECAST AREA. ISOLATED
SHOWERS AND THUNDERSTORMS WERE SITUATED MAINLY ALONG THE
INTERNATIONAL BORDER OVER THE NORTH CENTRAL AND NORTHWEST, LIFTING
INTO CANADA, WITH A FEW ADDITIONAL CELLS OVER SOUTH CENTRAL ND
INTO THE JAMES RIVER VALLEY. CONVECTION CONTINUES A DOWNWARD TREND
EARLY THIS MORNING.
FOR TODAY, WE ARE EXPECTING ANOTHER ROUND OF ISOLATED TO SCATTERED
THUNDERSTORMS ACROSS WESTERN AND CENTRAL ND, MAINLY THIS AFTERNOON
INTO THIS EVENING, BUT A FEW STORMS COULD DEVELOP A BIT EARLIER.
THE THREAT FOR SEVERE WEATHER SEEMS LIMITED AGAIN TODAY, PERHAPS
EVEN MORESO THAN YESTERDAY. WITH DAYTIME HEATING WE AGAIN
DESTABILIZE THIS AFTERNOON WITH MLCAPES OF 1000-2000 J/KG ACROSS
THE FORECAST AREA, BUT BULK SHEAR REMAINS LOW (GENERALLY AROUND 20
KNOTS). SHEAR DOES INCREASE LATE TONIGHT IN THE WEST BUT THIS IS
AFTER THE CAPE HAS DIMINISHED. THERE IS A PRETTY LARGE DISCREPANCY
BETWEEN NAM/RAP (HIGH) AND GFS (LOW) ML CAPE VALUES. NOT SURE
WHICH IS CORRECT AND RESULTING CAPE PROBABLY WILL LIE SOMEWHERE IN
THE MIDDLE. IN ANALYZING BUFKIT SOUNDINGS AND RAP LAYER RH, IT
SEEMS LIKE THERE MAY BE MORE CLOUDS AROUND TODAY, POSSIBLY KEEPING
TEMPERATURES A BIT LOWER THAN THURSDAY, AND MUTING CAPE VALUES
SOMEWHAT.
CAPE IS ALSO MORE OF A TALL SKINNY CAPE TODAY, WHICH WOULD ALSO
SEEM TO LIMIT THE SEVERE POTENTIAL, BUT INCREASING THE HEAVY RAIN
POTENTIAL. THE NAEFS SA PAGE CONTINUES TO HIGHLIGHT NORTHWEST ND
WITH PWAT VALUES GREATER THAN THE 99TH PERCENTILE, CENTERED AROUND
00 UTC SATURDAY. BASED ON THE MEAN WINDS THE STORM MOTION WOULD
BE NORTH NORTHWEST. AN INCREASING LOW LEVEL JET THIS EVENING WOULD
RESULT IN SLOW MBE VELOCITIES. WARM CLOUD DEPTH DOES INCREASE
THROUGH THE EVENING BUT IS INITIALLY PRETTY LOW TODAY. BY THE TIME
INGREDIENTS FOR HEAVY RAIN REACH THEIR MAX, THE FORCING FOR
ASCENT MAY HAVE DIMINISHED ENOUGH THAT CONVECTION MAY NOT BE
POSSIBLE IN OUR NECK OF THE WOODS. ESPECIALLY AS THE UPPER LEVEL
RIDGING THAT WE'VE BEEN TALKING ABOUT THE PAST FEW DAYS CONTINUES
TO BUILD OVER THE AREA. WILL CONTINUE TO MONITOR THROUGH THE DAY
FOR THE POTENTIAL FOR HEAVY RAIN, BUT GIVEN THE UNCERTAINTY IN
CONVECTION UNDER THE BUILDING UPPER HEIGHTS, WILL HOLD OFF ON ANY
HEIGHTENED MESSAGING FOR NOW.
HIGHS TODAY ARE FORECAST TO BE MAINLY IN THE 80S, WITH THE WARMEST
READINGS OVER EASTERN PORTIONS OF CENTRAL ND. LOWS TONIGHT WILL
AGAIN BE IN THE MID 50S TO MID 60S. STUCK VERY CLOSE TO GIVEN NBM
GUIDANCE TODAY GIVEN THE UNCERTAINTY IN SKY COVER LIMITING DAYTIME
HEATING.
LONG TERM
(SATURDAY THROUGH THURSDAY)
ISSUED AT 216 AM CDT FRI JUN 2 2023
DAILY DIURNALLY DRIVEN CONVECTION WILL BE THE MAIN FORECAST ISSUE
IN THE LONG TERM PERIOD.
THROUGH THE ENTIRE EXTENDED PERIOD FORECAST TEMPERATURES ARE
EXPECTED TO REMAIN QUITE UNIFORM WITH HIGHS GENERALLY IN THE 80S
AND LOWS IN THE MID 50S TO MID 60S. THE ENVELOPE OF NBM ENSEMBLE
TEMPERATURES SOLUTIONS REMAINS NARROW THROUGH EARLY NEXT WEEK, AND
DOES START TO WIDEN A BIT BY MID WEEK. OVERALL THOUGH, CONFIDENCE
IN THE TEMPERATURE FORECAST REMAINS HIGH THROUGH THE PERIOD.
SATURDAY AND SUNDAY WILL ONCE AGAIN BRING DAILY DIURNALLY DRIVEN
THUNDERSTORM CHANCES, WITH SLIGHT TO MODERATE INSTABILITY EACH
AFTERNOON, BUT WITH LITTLE SHEAR. THUS LIMITING THE SEVERE
POTENTIAL, AND WITH THE UPPER RIDGE GETTING CLOSER, THINK THE
COVERAGE WILL ALSO NOT BE AS EXTENSIVE AS THE PAST FEW DAYS.
EARLY NEXT WEEK A BACK DOOR COLD FRONT PUSHES INTO THE FORECAST
AREA, AND WILL BE A FOCUS FOR CONVECTION EACH DAY, AS IT SLOWLY
PUSHES WEST. HOWEVER, THE THREAT FOR SEVERE WEATHER WILL REMAIN
LOW GIVEN THE WEAK SHEAR ENVIRONMENT.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 604 AM CDT FRI JUN 2 2023
SCATTERED THUNDERSTORMS AND SOUTHEAST FLOW CONTINUE.
MAINLY VFR CONDITIONS EXPECTED THROUGH THE PERIOD WITH A
SOUTHEAST SURFACE FLOW. FLOW WILL BE A LITTLE STRONGER THIS
AFTERNOON THAN THE PAST FEW DAYS, GENERALLY UP TO 15-25 KNOTS. HIT
AND MISS THUNDERSTORM ACTIVITY IS ONCE AGAIN POSSIBLE THIS
AFTERNOON AND EVENING, WITH LOCAL MVFR CIGS/VSBYS AND GUSTY AND
ERRATIC WINDS POSSIBLE WITH ANY STORMS.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...TWH
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...TWH
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