573
FXUS63 KBIS 032025
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
325 PM CDT MON AUG 3 2020
SHORT TERM
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 232 PM CDT MON AUG 3 2020
PRECIPITATION CHANCES ENTER THE FORECAST AREA LATE TONIGHT AND
SPREAD ACROSS CENTRAL ND ON TUESDAY.
CONVECTION CURRENTLY MOVING FROM WESTERN INTO CENTRAL MT WILL
HAVE A HARD TIME MAINTAINING ITSELF AS IT MOVES INTO A LESS
FAVORABLE, DRIER ENVIRONMENT OVER WESTERN ND LATER THIS EVENING.
HOWEVER, A STRENGTHENING LOW LEVEL JET AND INCREASED FORCING FOR
ASCENT WITH AND APPROACHING SHORTWAVE, SHOULD ALLOW FOR SHOWERS
AND POSSIBLY A FEW THUNDERSTORMS TO PUSH INTO WESTERN ND TOWARD
MORNING. THE SHORTWAVE THEN PUSHES TO THE SOUTHERN SASK/MANITOBA
BORDER BY 00 UTC WEDNESDAY. THE QUESTION THEN BECOMES WHAT ABOUT
STRONG TO SEVERE CONVECTION ON TUESDAY INTO TUESDAY EVENING. THERE
IS STILL SOME DISAGREEMENT IN THE DETERMINISTIC MODEL SOLUTIONS,
BUT A SURFACE TROUGH IS LIKELY TO BE SITUATED SOMEWHERE OVER
WESTERN ND TUESDAY AFTERNOON. MOST OF THE MODELS AND CAMS THAT GO
OUT THAT FAR, PUSH THE MORNING CONVECTION EAST INTO CENTRAL ND,
AND THEN IT'S A MATTER OF WHETHER THE ATMOSPHERE CAN RECOVER
ENOUGH TUESDAY AFTERNOON TO SUPPORT SOME STRONGER CONVECTION IN
THE WEST. CONVECTION MODE LOOKS MESSY WITH NEITHER DIRECTLY
PERPENDICULAR, NOR PARALLEL BULK SHEAR VECTORS WITH THE SURFACE
BOUNDARY. ALSO, SOME CONVECTION MIGHT FIRE BACK WEST OF THE
BOUNDARY. THIS LOOKS LIKE IT COULD BE THE BEST LOCATION FOR
STRONGER STORMS JUST BASED ON FORECAST SOUNDINGS. WEST OF THE
BOUNDARY LATER WEDNESDAY AFTERNOON OR EARLY EVENING. YOU HAVE
UNIDIRECTIONAL SHEAR BUT DECENT SPEED SHEAR, 30-40 KNOTS OF BULK
SHEAR AND 1000-2000 J/KG OF CAPE. ENOUGH TO SUPPORT SOME STRONG
CONVECTION. HOWEVER, THERE APPEARS TO BE QUITE A BIT OF WARM AND
DRY AIR AROUND 500MB SO AT THIS TIME DO NOT THINK THE THREAT FOR
SEVERE STORMS IS THAT HIGH. SPC MAINTAINS A GENERAL RISK EXCEPT
FOR A MARGINAL RISK IN THE FAR SOUTHWEST/SOUTH CENTRAL WITH
BETTER INSTABILITY AS YOU GO FARTHER SOUTH INTO SD. ALSO WOULD NOT
COMPLETELY RULE OUT A STRONGER CELL TO THE NORTH, CLOSER TO THE
AFOREMENTIONED SHORTWAVE TROUGH. SOME GUIDANCE ALSO KEEPS STRONGER
CONVECTION ALONG AND AHEAD OF THE TROUGH TUESDAY AFTERNOON, AND
THINK EITHER SCENARIO IS POSSIBLE. BUT IN GENERAL THE SEVERE
THREAT LOOKS TO BE LIMITED TUESDAY INTO TUESDAY NIGHT.
LONG TERM
(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 232 PM CDT MON AUG 3 2020
THE EXTENDED FORECAST IS HIGHLIGHTED BY A CHANCE OF THUNDERSTORMS
WEDNESDAY, AND AGAIN OVER THE WEEKEND, ALONG WITH TEMPERATURES
INCREASING TO NEAR TO ABOVE AVERAGE.
SLIGHT CHANCE TO CHANCE POPS CONTINUES WEDNESDAY MORNING AND
AFTERNOON WITH SOME GUIDANCE CONTINUING TO WRAP SHOWERS AND
THUNDERSTORMS AROUND THE BACK SIDE OF THE SHORTWAVE, AND STILL
WANT TO KEEP THE CHANCE IN FOR NOW.
HIGHS WILL GENERALLY BE IN THE UPPER 70S TO MID 80S TUESDAY AND
WEDNESDAY, BEFORE QUICKLY WARMING UP TO THE LOWER 80S EAST TO NEAR
90 WEST ON THURSDAY AS UPPER RIDGING BEGINS TO BUILD AGAIN OVER
THE NORTHERN PLAINS. MAYBE A SLIGHT CHANCE FOR A FEW THUNDERSTORMS
IN THE WEST ON THURSDAY AFTERNOON, BUT A BETTER CHANCE EMERGES
FRIDAY WITH ANOTHER SHORTWAVE AND FRONTAL SYSTEM MOVING THROUGH.
FOR THE WEEKEND AND INTO NEXT WEEK, LOOKING LIKE NEAR DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS ALONG WITH TEMPERATURES
GENERALLY IN THE 80S.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 232 PM CDT MON AUG 3 2020
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MODERATE
SOUTHEAST FLOW 15 TO 30KT AT KXWA AND KDIK TODAY. OTHERWISE SUNNY
WITH A FEW VFR CUMULUS CLOUDS AND POSSIBLY SOME THIN HIGH CLOUDS
MOVING IN FROM THE WEST. CLOUDS INCREASE SIGNIFICANTLY LATE
TONIGHT WEST WITH SHOWERS AND POSSIBLY A THUNDERSTORM MOVING INTO
KDIK AND KXWA AFTER 12 UTC. GIVEN THE UNCERTAINTY OF THUNDER AT
THIS TIME, JUST KEPT A VCSH AT THESE SITES 12-18 UTC.
BIS WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...TWH
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