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FXUS63 KUNR 012022
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
122 PM MST THU JAN 1 2026
KEY MESSAGES
- AREAS OF FOG, DENSE AT TIMES, REFORMING ACROSS THE NORTHWEST
AND CENTRAL COUNTIES OVERNIGHT.
- A LITTLE COOLER FOR FRIDAY, BUT WARMING BACK UP FOR THE WEEKEND
AND STAYING DRY
DISCUSSION
(THIS EVENING THROUGH THURSDAY)
ISSUED AT 120 PM MST THU JAN 1 2026
LATEST ANALYSIS SHOWS WESTERN CONUS RIDGE IN PLACE ACROSS THE
ROCKIES WITH MILD NORTHWEST FLOW IN PLACE ACROSS THE REGION.
CLOSED 500HPA LOW SPINNING ONSHORE ACROSS SOUTHERN CA WITH NEXT
LITTLE RIPPLE IN 500HPA FLOW NOW MOVING THROUGH 500HPA RIDGE IN
EASTERN ID/WESTERN WY. AT THE SURFACE, LOW PRESSURE IS LOCATED IN
SOUTH CENTRAL SD LOCATED ALONG COLD FRONT THAT STRETCHES NORTHWEST
WARD INTO CENTRAL MT. NORTH OF THIS BOUNDARY, TEMPS ARE IN THE
MID 20S, SOUTH OF THE BOUNDARY MID TO UPPER 50S ARE THE RULE.
AS THE AFOREMENTIONED 500HPA WAVE TRAVERSES THROUGH THE RIDGE THEN
DROPS INTO THE REGION OVERNIGHT, IT WILL PULL THIS COLD
FRONT/BOUNDARY FURTHER WEST AND SOUTH. LOW CLOUDS/FOG IN
ND/EASTERN SD WILL ALSO OOZE TO THE WEST AS WELL. LOW LEVEL
CONDENSATION PRESSURE DEFICITS...ESPECIALLY ACROSS THE NORTHERN
FORECAST AREA FALL INTO THE 20MB RANGE OR LESS OVERNIGHT AND
NOTICED THAT ENSEMBLES ARE SHOWING PROBABILITIES THAT VISIBILITIES
WILL FALL TO A MILE OR LESS AT 50-60% ACROSS MUCH OF OUR NORTHERN
COUNTIES. GIVEN THAT WE HAD DENSE FOG OCCUR THIS MORNING, WILL
STICK WITH PERSISTENCE AND PLAN ON IT OCCURRING AGAIN OVERNIGHT. A
DENSE FOG ADVISORY WILL BE ISSUED FROM 00Z FRIDAY TO 15Z FRIDAY.
THE OTHER ISSUE IS THE PROBABILITY OF PCPN WITH THE 500HPA WAVE AS
IT MOVE ACROSS MAINLY NE LATE TONIGHT INTO FRIDAY MORNING. THERE
REMAINS CONTINUED 700HPA THETA-E FORCING ASSOCIATED WITH THIS WEAK
WAVE, AND FORECAST SOUNDINGS FROM THE SOUTHEAST FORECAST AREA
INDICATES A LAYER OF WARM AIR ABOVE THE COLD AIR AT THE SURFACE,
LEADING TO THE POSSIBILITY OF -FZRA, IF THE COLUMN CAN SATURATE
ENOUGH. HAVE KEPT INHERITED LOW POPS FOR THE AREA.
WAA RETURNS BACK TO THE REGION BEGINNING FRIDAY NIGHT AND
CONTINUES THROUGH THE WEEKEND. HIGHS WILL ONCE AGAIN BE WELL ABOVE
SEASONAL NORMS AS THE UPPER RIDGE SHIFTS INTO THE CENTRAL PLAINS.
HOWEVER, THERE ARE SOME SIGNS THAT COLDER...NOT COOLER...TEMPS ARE
HEADED OUR WAY TOWARD THE END OF NEXT WEEK WITH INCREASING PCPN
CHANCES. STAY TUNED.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1031 AM MST THU JAN 1 2026
EXPECT VFR CONDITIONS TO PREVAIL ACROSS THE TERMINALS THROUGH THE
VALID TAF PERIOD. SOME PATCHY AREAS OF FG WILL DEVELOP LATE THIS
EVENING BUT SHOULD NOT IMPACT THE TERMINALS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...DENSE FOG ADVISORY FROM 5 PM THIS AFTERNOON TO 8 AM MST FRIDAY
FOR SDZ001-002-012>014-032-073-078.
WY...NONE.
DISCUSSION/KEY MESSAGES...HINTZ
AVIATION...WOODWARD
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