528
FXUS63 KUNR 212301
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
501 PM MDT TUE OCT 21 2025
KEY MESSAGES
- DRY, WITH WARMING TEMPERATURES FOR THE REST OF THE WEEK
- POTENTIAL PATTERN CHANGE BY SUNDAY
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 115 PM MDT TUE OCT 21 2025
NOT MUCH OF NOTE IN THIS FORECAST UPDATE FROM THE PREVIOUS
FORECAST PACKAGE. LARGE AREA OF LOW PRESSURE THAT BROUGHT THE
SHOWERS AND STRONG WINDS TO THE AREA YESTERDAY CONTINUES TO SPIN
OFF TO THE EAST ACROSS NORTHERN MINNESOTA THIS AFTERNOON. BEHIND
THIS SYSTEM SUBSIDENCE AND INCREASED HEIGHTS HAVE MOVED INTO MUCH
OF EASTERN WYOMING AND WESTERN SOUTH DAKOTA. THIS TRANSLATES TO
MOSTLY SUNNY SKIES WITH MILD TEMPERATURES. ALL LONG RANGE
DETERMINISTIC MODELS ARE IN GOOD AGREEMENT IN DEVELOPING A REX
BLOCK PATTERN OVER MUCH OF THE WESTERN CONUS, WITH THE CENTER OF
THE RIDGE AXIS HANGING OUT OVER THE FRONT RANGE. TYPICALLY THESE
BLOCKING PATTERNS REMAIN OVER A GEOGRAPHICAL AREA FOR LONG PERIODS
OF TIME AND ALL INDICATIONS SUGGEST FROM BOTH THE LONG RANGE
MODELS AND ENSEMBLE MEMBERS, THAT THIS REX BLOCK PATTERN WILL BE
IN PLACE THROUGHOUT THE REST OF WEEK AND INTO THE WEEKEND. THIS
WILL MEAN A LONG PERIOD OF DRY CONDITIONS WITH GRADUALLY WARMING
TEMPERATURES ACROSS THE REGION. TEMPERATURES COULD CLIMB INTO THE
LOW TO MID 70S ON SATURDAY.
MODELS DIVERGE ON HOW QUICKLY TO MOVE OUT AND BREAKDOWN THE REX
BLOCK PATTERN, MODELS TEND TO WANT TO MOVE/BREAKDOWN THESE
BLOCKING PATTERNS TOO FAST SO CONFIDENCE IN BRINING IN THIS NEXT
STORM SYSTEM INTO THE AREA REMAINS LOW. EVENTUALLY WHEN THIS
SYSTEM DOES PUSH INTO OUR REGION, SOME SIGNIFICANT CHANGES TO THE
WEATHER PATTERN MAY BE THE RESULT IN TERMS OF TURNING MUCH COLDER
AND WETTER.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 501 PM MDT TUE OCT 21 2025
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...WOODWARD
AVIATION...HELGESON
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