080
FXUS63 KUNR 061718
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1118 AM MDT MON JUL 6 2026
KEY MESSAGES
-ACTIVE THROUGH MID WEEK AS A SERIES OF DISTURBANCES MOVE THROUGH
THE REGION, WITH SEVERE THUNDERSTORMS POSSIBLE
-VERY HOT THIS WEEKEND WITH RECORD HIGH TEMPS POSSIBLE AND
DANGEROUS HEAT SAT AND SUNDAY
DISCUSSION
(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1118 AM MDT MON JUL 6 2026
IMPULSE FILLED WESTERLY FLOW WILL BE IN PLACE OVER THE REGION
THROUGH MID WEEK AS A FRONTAL BOUNDARY STALLS OVER THE REGION.
NEAR DAILY CHANCES FOR THUNDERSTORMS CAN BE EXPECTED WITH SEVERE
STORMS POSSIBLE AT TIMES. TUES LOOKS TO BE THE BEST CHANCE FOR
SEVERE STORMS AS APPRECIABLE CAPE AND MODERATE BULK DEEP LAYER
SHEAR WILL BE IN PLACE. FRONTAL BOUNDARY HAS SHIFTED SOUTH THROUGH
MOST THE FA THIS MORNING AND WILL HANG UP IN SCENTRAL SD. SFC
BASED TS WILL BE POSSIBLE ALONG THE FRONT THIS AFTERNOON AS
DIURNAL HEATING ALLOWS THE CAP TO BE OVERCOME. FURTHER WEST,
ISOLATED TS WILL BE POSSIBLE OVER THE CENTRAL AND SOUTHERN BH
WHERE EDDY CONVERGENCE WILL BE IN PLACE WITH INCREASING MOISTURE
BEHIND THE FRONT. CONVECTION WILL WANE ACROSS THESE AREAS INTO THE
EVENING. HOWEVER, AN UPPER LEVEL IMPULSE WILL SUPPORT POS THETA-E
ADV ACROSS NORTHEAST WY OVERNIGHT, WITH A COMPLEX OF STORMS
POSSIBLE, AS HINTED AT IN HIRES MODELS. STORMS WILL CARRY ACROSS
NW SD OVERNIGHT INTO TUE MORNING. SFC FRONT WILL BE STALLED ACROSS
THE FA TUE, THE LOCATION OF WHICH WILL BE DICTATED BY OUTFLOW
FROM STORMS TO THE NORTH. MODERATELY STRONG IMPULSE WILL KICK OUT
OF WY/MT IN THE THE AFTERNOON AND EVENING AND WILL DRIVE CI THERE.
STORMS MAY ALSO FIRE ALONG THE FRONT IF CAPPING CAN BE OVERCOME,
THE STRENGTH OF WHICH VARIES IN FORECAST MODELS (CAPPING THAT IS).
GIVEN PROGGED ML CAPE OF 1-2 KJ/KG, DEEP BULK LAYER SHEAR OF 40
TO 50 KNOTS, EXPECT SUPERCELLS TO BE POSSIBLE WITH STRONG ROTATING
UPDRAFTS, CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. IN
ADDITION, GIVEN ESE FLOW INVOF OF THE SFC FRONT, THERE WILL BE A
SMALL CHANCE FOR TORNADOES. STORMS WILL CARRY ACROSS THE REGION
THROUGH THE EVENING. MORE STORMS ARE POSSIBLE WED AND THUR AS
SUFFICIENT LL MOISTURE WILL BE IN PLACE WITH WEAK STABILITY AND
ADDITIONAL IMPULSES. UPPER RIDGE BUILDS INTO THE REGION THIS
WEEKEND, WITH DRY AND HOT CONDS EXPECTED. IMPRESSIVE TEMPS OF 35
TO ALMOST 40C AT H85 WITH CLOSE TO 6000 H5 HEIGHTS OVER WY, WILL
OFFER RECORD TO NEAR RECORD HIGHS WELL INTO THE 100S WITH 110 TO
115 POSSIBLE ON PORTIONS OF THE PLAINS, ESP SUNDAY.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 531 AM MDT MON JUL 6 2026
BREEZY NORTH TO NORTHWEST WINDS ARE EXPECTED TODAY ACROSS THE
REGION BEHIND A WEAK COOL FRONT, ALONG WITH A REINTRODUCTION OF
ISOLATED THUNDERSTORMS STARTING AFTER 19Z/1PM THIS AFTERNOON FIRST
OVER THE BLACK HILLS, THEN EXPANDING ACROSS THE REGION AND
CONTINUING OVERNIGHT TONIGHT. VFR CONDITIONS ARE GENERALLY
EXPECTED, BUT BRIEF MVFR CONDITIONS ARE POSSIBLE NEAR/UNDER ANY
THUNDERSTORM. STORM CHANCES MAY INCREASE FOR A TIME THIS EVENING
ACROSS NORTHEAST WYOMING, AND HAVE INTRODUCED A PROB30 GROUP AT
KGCC BETWEEN 03-08Z/9PM-2AM BASED ON THE LATEST CAMS. OTHERWISE,
OVERALL STORM CHANCES WILL REMAIN ISOLATED TONIGHT AND TUESDAY
MORNING, BEFORE INCREASING REGIONWIDE TUESDAY AFTERNOON.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...JC
AVIATION...KSMITH
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