759
FXUS63 KUNR 221109
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
509 AM MDT SUN JUN 22 2025
KEY MESSAGES
- MARGINAL RISK (1 OUT OF 5) OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON/EVENING, ESPECIALLY OVER SOUTHERN SD
- UNSETTLED NEXT WEEK WITH SEASONAL TEMPERATURES WITH A SLIGHT
RISK (2 OUT OF 5) OF SEVERE THUNDERSTORMS TUESDAY
DISCUSSION
(TODAY THROUGH SATURDAY)
ISSUED AT 149 AM MDT SUN JUN 22 2025
07Z SURFACE ANALYSIS HAD COOL FRONT FROM CENTRAL MN TO KICR TO
NORTHEASTERN CO WITH A LOW PRESSURE OVER NORTHEASTERN CO. WATER
VAPOUR LOOP HAD UPPER RIDGE OVER THE EASTERN CONUS AND TROUGH OVER
THE NORTHWEST CONUS. CWA HAD SOUTHWEST FLOW ALOFT WITH NEXT WAVE
OF INTEREST OVER EASTERN ID/UT. AHEAD OF THESE FEATURES EARLY THIS
MORNING, 50KT LOW-LEVEL JET IGNITING TSRA (2-3KJ/KG MUCAPE, WEAK
EFFECTIVE SHEAR) OVER SOUTH-CENTRAL SD WITH REGIONAL RADARS
SHOWING ADDITIONAL CONVECTION DEVELOPING IN/NEAR MT/WY/ND BORDERS
PER 700MB THETA-E ADVECTION (1KJ/KG MUCAPE, 35-45KT EFFECTIVE BULK
SHEAR). EXPECT BEST CONVECTION TO BE NORTHEAST/NORTH OF CWA
OVERNIGHT, BUT CAN'T RULE OUT A STRONGER STORM MAINLY OVER
NORTHWESTERN SD. EFFECT OF ID/UT WAVE THE MAIN SHORT TERM FORECAST
CONCERN.
TODAY/TONIGHT, ID/UT WAVE LIFTS NORTHEAST WITH MODEST QG-
FORCING. NORTHEAST CO LOW WILL MOVE ALONG COOL FRONT INTO EASTERN
SD PUSHING COOL FRONT SOUTH OF CWA TONIGHT. PERSISTENT THETA-E
ADVECTION AHEAD OF IT WILL PROMOTE ISOLATED/SCATTERED SHRA/TS IN
THE NORTH THIS MORNING AND THEN OVER THE WESTERN SD PLAINS LATER
THIS AFTERNOON/EVENING. BUOYANCY WILL AVERAGE <1KJ/KG IN POST
FRONTAL ENVIRONMENT WITH RAPIDLY INCREASING VALUES AHEAD OF THE
COOL FRONT. 0-6KM BULK SHEAR BEST POST-FRONTAL. CAMS SHOW ACTIVE
STORMS OVER SOUTHWESTERN SD (BLACK HILLS DOWNSTREAM CONVERGENCE
PER NORTHERLY WINDS HELPING CONVECTIVE INITIATION) LATER THIS
AFTERNOON, MOVING EAST INTO SOUTH-CENTRAL SD THIS EVENING.
STRONGEST CONVECTION SHOULD BE ASSOCIATED WITH FRONT EAST OF CWA.
THUS, MARGINAL RISK (1 OUT OF 5) OF SEVERE THUNDERSTORMS
REASONABLE OVER THE CWA. HIGH TEMPERATURES THIS AFTERNOON WILL BE
TRICKY WITH POST-FRONTAL LOW CLOUDS SQUASHING POTENTIAL
TEMPERATURES IN THE NORTHWEST, SO DIDN'T STRAY FAR FROM GUIDANCE.
NEXT WEEK, UPPER TROUGH MOVES EAST OF THE AREA WITH
WEST/SOUTHWEST FLOW ALOFT AND SEVERAL PERTURBATIONS ZIPPING
THROUGH THE FLOW. RETURN FLOW TUESDAY WILL PROMOTE INCREASING
BUOYANCY AND SUFFICIENT SHEAR FOR THE POSSIBILITY OF SEVERE
THUNDERSTORMS PER SPC DAY 3 SLIGHT RISK. AFTER THAT, HARDER TO
PINPOINT FOCUSED AREAS OF PRECIPITATION AND/OR ACTIVE
THUNDERSTORMS, BUT IT'S JUNE SO WOULDN'T BE SURPRISED TO SEE
SPRITZES OF STRONG/SEVERE TSRA WITH LAST NIGHTS CSU MLP
PORTRAYING THAT SCENARIO.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 505 AM MDT SUN JUN 22 2025
MVFR/LOCAL IFR CIGS OVER MUCH OF THE AREA THIS MORNING WILL LIFT
NORTHEAST THIS AFTERNOON LEAVING MAINLY VFR CONDITIONS BEHIND.
PATCHY IFR FOG WILL END THIS MORNING. ISOLATED/SCATTERED SHRA/TS
WILL BECOME MORE NUMEROUS THIS AFTERNOON/EARLY EVENING WITH LOCAL
IFR CONDITIONS, PARTICULARLY ACROSS SOUTHERN SD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...HELGESON
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