789
FXUS63 KUNR 060409
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1009 PM MDT TUE MAY 5 2026
KEY MESSAGES
- ACTIVE NORTHWEST FLOW THROUGH WILL PERSIST THROUGH THE WEEK WITH
RAIN AND THUNDERSTORM CHANCES, BEST CHANCES THURSDAY AND
SATURDAY.
- COOLER TEMPERATURES PERSIST WEDNESDAY BEFORE WARMING TREND INTO
THE WEEKEND.
UPDATE
ISSUED AT 933 PM MDT TUE MAY 5 2026
LINGERING SHOWERS ACROSS FAR SW SD WILL DISSIPATE THIS EVENING
WITH DRY CONDS AND CLEARING SKIES EXPECTED. THIS WILL SUPPORT
STRONG RADIATIONAL COOLING AS WINDS DROP OFF.
MAIN CHANGE TO THE PREVIOUS FORECAST WAS TO RAISE POPS THUR
AFTERNOON WITH THE STRONG NW FLOW IMPULSE. FAIRLY UNSTABLE
PROFILES WITH AMPLE PAC MOISTURE WILL SUPPORT A GOOD CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS IN THE AFTERNOON OVER NORTHEAST
WY INTO SW SD. OTHERWISE, TWEAKED HIGHS/LOWS THE NEXT COUPLE DAYS
WITH NO OTHER SIG CHANGES.
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 1240 PM MDT TUE MAY 5 2026
A STRONG MID-LEVEL LOW IS CENTERED OVER NORTHEASTERN ONTARIO WITH
AN UPPER TROUGH AXIS STRETCHING WESTWARD THROUGH THE NORTHERN
PLAINS. WATER VAPOR IMAGERY SHOWS A VORT MAX PUSHING THROUGH THE
FORECAST AREA WITH ACTIVE NORTHWESTERLY FLOW UPSTREAM. SURFACE
HIGH PRESSURE IS CENTERED OVER EASTERN MANITOBA WITH BRISK
NORTHWEST SURFACE FLOW ACROSS THE NORTHERN PLAINS. COLD AIR ALOFT
+ STEEP LOW-LEVEL LAPSE RATES HAVE RESULTED IN A CELLULAR CU FIELD
WITH VIRGA/SPRINKLES POSSIBLE ACROSS NW SD. LIGHT SHOWERS
POSSIBLE ACROSS THE SW THIRD OF THE FORECAST AREA AS THE WAVE
PIVOTS THROUGH THE REGION. ANY PRECIPITATION AMOUNTS WILL BE
MINIMAL.
COOLER WEATHER PERSISTS TOMORROW WITH GENERALLY DRY CONDITIONS AS
SUBSIDENCE OVERSPREADS THE AREA THROUGH THE DAY. THERMAL RIDGE
AXIS WILL PUSH EASTWARD THURSDAY INTO THE WEEKEND WITH TEMPERATURES
WARMING THROUGH THE WEEKEND.
ACTIVE NORTHWEST FLOW PERSISTS THROUGH THE WEEK WITH ANOTHER COMPACT
SHORTWAVE TROUGH TO ARRIVE THURSDAY WITH RAIN SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY AFTERNOON. GENERALLY DRY CONDITIONS FRIDAY AHEAD
OF ANOTHER WAVE THAT WILL BRING ADDITIONAL SHOWER AND THUNDERSTORM
CHANCES TO THE AREA SATURDAY.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1008 PM MDT TUE MAY 5 2026
VFR CONDITIONS THROUGH THE TAF PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...JC
DISCUSSION/KEY MESSAGES...SE
AVIATION...SCHULTZ
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