352
FXUS63 KUNR 141734
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1134 AM MDT SUN SEP 14 2025
KEY MESSAGES
- SOGGY SUNDAY FOR SECTIONS OF WESTERN SD
- DRYING OUT AND WARMER ON MONDAY
- BECOMING MORE UNSETTLED MID-WEEK
DISCUSSION
(TODAY THROUGH SATURDAY)
ISSUED AT 241 AM MDT SUN SEP 14 2025
LATEST WATER VAPOR IMAGERY SHOWS A NEGATIVE TILTED 500HPA TROUGH
LOCATED ACROSS EASTERN MT SOUTH INTO EASTERN NM, WITH CLOSED
500HPA LOW SPINNING ACROSS NORTHEAST CO/SOUTHEAST WY. PLENTY OF
MOISTURE IS STREAMING NORTHWARD INTO THE NORTHERN HIGH PLAINS IN
ADVANCE OF THIS LOW, WITH RADAR SHOWING WIDESPREAD SHOWERS FROM SW
SD INTO CENTRAL SD. WATER VAPOR IMAGERY ALSO SHOWS MID-WEEK
SYSTEM CRASHING ONSHORE IN OR, WITH RIDGING TAKING PLACE BETWEEN
THE TWO 500HPA LOWS. AT THE SURFACE, LOW PRESSURE IS LOCATED IN SW
NEB/NE CO WITH AN INVERTED SURFACE TROUGH POKING NORTHEAST INTO
CENTRAL ND.
AFOREMENTIONED 500HPA TROUGH WILL CONTINUE TO MOVE EASTWARD, IMPACTING
THE CWA THROUGH MUCH OF THE DAY. SOUTHERLY FETCH OF GULF MOISTURE
WILL SPELL CLOUDINESS OVER THE REGION THROUGH THE DAY, HELPING TO
KEEP TEMPS IN CHECK WHEN COMPARED TO PREVIOUS DAY. LIGHT
NORTHEAST TO EASTERLY WINDS WILL PRODUCE UPSLOPE LOW CLOUDS ALONG
THE EAST SIDE OF THE BLACK HILLS FOR MUCH OF THE DAY. THERE IS
SOME CONCERN AS TO HOW FAR WEST THE NORTHWARD ADVANCING RAIN
SHIELD WILL MAKE IT, GIVEN DRY AIR ALREADY TRYING TO PUSH IN FROM
WYOMING. FEEL THAT MOST OF THE PCPN WILL BE CONFINED AROUND THE
INVERTED SURFACE TROUGH THAT IS LOCATED EAST OF THE BLACK HILLS,
SO THAT IS WHERE THE HIGHEST POPS WILL BE CONFINED FOR MUCH OF THE
DAY TODAY. THIS IS ALSO WHERE ENSEMBLES ARE PAINTING THE HIGHEST
PROBABILITIES (45-70%) OF SEEING DAYTIME RAINFALL TOTALS > 1 INCH.
THIS ALSO LINES UP FAIRLY CLOSELY WITH 700HPA TROWAL ANALYSIS.
700HPA THETA-E DOWNGLIDE BEGINS TO IMPACT THE WESTERN CWA BY 21Z
THIS AFTERNOON, WHICH SHOULD LEAD TO DECREASING CLOUD COVER AND
OVERALL IMPROVING CONDITIONS.
AS THE 500HPA TROUGH ROTATES/LIFTS NORTHEAST OUT OF THE AREA, WILL
SEE GENERALLY IMPROVING CONDITIONS AND AN END TO THE RAINFALL
DURING THE EVENING AND OVERNIGHT HOURS. THE FAR NORTHEAST PART OF
THE CWA WILL BE THE LAST TO DRY OUT AND SEE THE DECREASE IN CLOUD
COVER OVERNIGHT. RIDGING WILL MOVE INTO THE AREA TO START THE WEEK
OFF ON MONDAY, WITH INCREASING 850HPA TEMPS. IT STILL APPEARS
THAT THE WARMEST PART OF THE CWA WILL BE SW SD WHERE SOME LOW 90S
CAN’T BE RULED OUT.
BEGINNING TUESDAY AND FOR THE REST OF THE WEEK, THINGS LOOK TO BE
MORE UNSETTLED AS NEXT 500HPA TROUGH IMPACTS THE NORTHERN PLAINS.
MODELS SHOW THIS TROUGH DEEPENING, WITH CLOSED 500HPA LOW ACTUALLY
DEVELOPING AND DIVING INTO THE CWA DURING THE DAY ON THURSDAY.
THIS SHOULD LEAD TO PLENTY OF CLOUD COVER, KEEPING A LID ON TEMPS
AS WELL AS KEEPING DAILY CHANCES FOR SHOWERS/STORMS IN THE
FORECAST. OF INTEREST MIGHT BE THE TEMPS FOR NEXT WEEKEND. MODELS
ARE SUGGESTING SINGLE DIGIT 850HPA TEMPS FOLLOWING ON THE HEELS OF
THE EXITING CLOSED 500HPA MOVING INTO THE REGION. COUPLED WITH
SUBSIDENCE HELPING TO SCOUR OUT ANY POTENTIAL CLOUDS, IT COULD SET
THE STAGE FOR SOME CHILLY MORNINGS. HOWEVER, THAT FAR OUT, THINGS
WILL MOST LIKELY CHANGE SEVERAL TIMES BEFORE NEXT WEEKEND ARRIVES.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1122 AM MDT SUN SEP 14 2025
MVFR CONDITIONS WILL CONTINUE AT RAP THROUGH AROUND 20Z. VFR
CONDITIONS ARE THEN EXPECTED TO PREVAIL THROUGH ACROSS THE
AIRSPACE. ISOLATED SHOWERS WILL IMPACT RAP THROUGH 01Z, AIDED BY
A FRONTAL MOVEMENT. NORTHEAST WINDS WILL SHIFT SOUTH/SOUTHWEST
THIS EVENING BEHIND SHOWERS.
AEH
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HINTZ
AVIATION...HERDLISKA
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