107
FXUS63 KUNR 030007
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
607 PM MDT SAT MAY 2 2026
KEY MESSAGES
- COLD FRONT DROPS THROUGH THIS AFTERNOON/EVENING, AND THEN
ANOTHER MONDAY, BRINGING GUSTY WINDS.
- MEAN NORTHWEST FLOW ALOFT BRINGS UNSETTLED WEATHER THROUGH MUCH
OF NEXT WEEK.
DISCUSSION
(THIS EVENING THROUGH SATURDAY)
ISSUED AT 1242 PM MDT SAT MAY 2 2026
18Z SURFACE ANALYSIS HAD LOW OVER NORTHEASTERN ND WITH COLD FRONT
INTO FAR NORTHERN WY/NORTHWEST SD, JUST ENTERING THE FAR
NORTHWEST REACHES OF THE CWA. WATER VAPOUR MATINEE HAD NORTHWEST
FLOW ALOFT WITH A COUPLE OF WEAK EMBEDDED SHORTWAVES HEADING FOR
THE NORTHERN PLAINS. NOT MUCH CU PER 0.5KM VISIBLE LOOP EARLY THIS
AFTERNOON (EVEN WITH WELL-MIXED 18Z KUNR SOUNDING - IT IS QUITE
DRY), BUT WEAK WAVE OVER ND SHOULD ASSIST A FEW MORE CU AND THE
POTENTIAL FOR ISOLATED -SHRA LATER THIS AFTERNOON OVER CENTRAL SD.
TONIGHT, COLD FRONT EXITS THE CWA WITH WEAK COLD AIR ADVECTION.
BEHIND IT AHEAD OF WEAK SHORTWAVE, EXPECT A NARROW BAND OF WEAK
800-600MB FRONTOGENESIS/THETA-E ADVECTION AND A TOUCH OF MUCAPE.
SHOULD BE SUFFICIENT FOR WEAK ELEVATED CONVECTION ACROSS
NORTHEASTERN WY/WEST-CENTRAL SD OVERNIGHT. SPC HREF PAINTBALLS
SUPPORT.
PRECIPITATION SHOULD WANE SUNDAY MORNING, BUT ADDITIONAL
-SHRA/TS WILL DEVELOP IN THE AFTERNOON PER MEAN 500J/KG SBCAPE AND
LIMITED SBCIN. BLACK HILLS LIKELY THE ORIGIN GIVEN TERRAIN
INFLUENCE, CONFIRMED BY HREF. MODEST 0-6KM BULK SHEAR COULD POP AN
ACTIVE STORM OR TWO, BUT WEAK BUOYANCY WILL LIMIT POTENTIAL.
CONVECTION DIES DOWN SUNDAY NIGHT.
SECOND COLD FRONT ARRIVES MONDAY WITH A STRONGER EMBEDDED
SHORTWAVE. RESULT WILL BE SOME SHOWERS ALONG WITH GUSTY NORTHWEST
WINDS PER PROBABILISTIC GUIDANCE (40-60% CHANCE 45MPH GUSTS FROM
K2WX-KRAP), ALTHOUGH ISALLOBARIC FORCING ISN'T THAT IMPRESSIVE.
CAN'T RULE OUT A FEW LIGHTNING STRIKES AS WELL AS SOME SNOW MIXING
IN UP HIGH, BUT IMPACTFUL SNOW ACCUMULATION IS NOT EXPECTED.
TUESDAY THROUGH SATURDAY, NORTHWEST FLOW ALOFT WILL BRING A SERIES
OF DISTURBANCES/FRONTS THROUGH THE CWA. TEMPERATURES 5-10F BELOW
NORMAL TUESDAY RISING TO 5-10F ABOVE BY SATURDAY.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 607 PM MDT SAT MAY 2 2026
GUSTY NORTHWEST WINDS BEHIND A COLD FRONT WILL CONTINUE THROUGH
03-04Z/9-10PM THIS EVENING, BEFORE SIGNIFICANTLY DROPPING OFF AND
LEAVING US WITH BKN HIGH-LEVEL CLOUDS ALONG WITH CONTINUED VFR
CONDITIONS. SUNDAY WILL BE CHARACTERIZED BY A CHANCE OF SHOWERS
AND PERHAPS ISOLATED EMBEDDED THUNDER IN THE MORNING, POSSIBLY
SOME SORT OF RELATIVE LULL MIDDAY, AND THEN REDEVELOPMENT OF
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DURING THE
AFTERNOON. OVERALL CONFIDENCE IN EITHER KGCC OR KRAP GETTING
DIRECTLY IMPACTED BY ANY OF THIS IS SOMEWHAT LOW, AND COMPARING
THE VARIOUS CAM SOLUTIONS OFFERS WEAK CONSENSUS ON TRYING TO
DEFINE/TIME OUT ANY LULL/BREAK BETWEEN THE TWO ROUNDS. DIDN'T
REALLY WANT TO ADVERTISE A DRY FORECAST THROUGHOUT THE PERIOD
GIVEN A FEW OF THE CAMS AS WELL AS NBM POPS, SO GENEROUSLY WENT
AHEAD WITH PROB30 GROUPS TO ADVERTISE A CHANCE OF -SHRA AND -TSRA
BETWEEN 11Z/5AM AND 23Z/5PM. WE'LL WATCH FOR OPPORTUNITIES TO
FURTHER ADJUST/DEFINE THESE START/END TIMES, AS WELL AS SEE IF A
BREAK CAN BE INTRODUCED IN BETWEEN THE MORNING AND AFTERNOON
ACTIVITY. IF A ZESTY STORM COMES NEAR A TERMINAL DURING THE
AFTERNOON, ERRATIC WIND GUSTS TO AT LEAST 35KTS WOULD BE POSSIBLE.
FIRE WEATHER
ISSUED AT 1242 PM MDT SAT MAY 2 2026
NEAR CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE THIS
AFTERNOON PER MINIMUM RELATIVE HUMIDITY IN THE TEENS AND WEST
(AHEAD OF COLD FRONT)/NORTHWEST WINDS (BEHIND COLD FRONT) AT 15-
25MPH.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...KSMITH
FIRE WEATHER...HELGESON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page