Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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380 FXUS63 KUNR 011116 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 516 AM MDT Mon Jul 1 2024 .KEY MESSAGES... -A few severe storms are possible today from southwest to central SD -Unsettled pattern will bring near daily chances for showers/storms through Thursday -Temps will be around normal, or on the cool side of normal most of this week, coolest Thur -Warmer and drier this weekend && .DISCUSSION...(Today Through Sunday) Issued at 120 AM MDT Mon Jul 1 2024 Fairly active northern stream will prevail this week with near daily chances for showers and storms through Thur as a frontal boundary wavers over the region and mean troughing prevails through mid week. Sfc cool front will slide into the region today as another stronger impulse ejects out of the Rockies. This impulse will support a good deal of LSA and strong forcing, allowing TS to develop in the afternoon over far western SD. Storms should grow upscale into isolated supercells and convective line segments, supporting large hail and damaging winds given bulk shear of 35-45 knots. CAPE will be somewhat limited in western SD topping out AOA 1000 J/kg, however dynamic forcing should make up for the lack of sig CAPE there. Deeper moisture and better CAPE will reside over central SD where storms will likely intensify as they shift east in the late afternoon. Further west across WY, plenty of shear will be in place for very isolated supercells, but given conditional nature of convection and limited CAPE, any severe threat will be very isolated. Temps will top out in the lower 90s from SW to central SD where skies clear out ahead of the cool front, with 70s and 80s elsewhere. Sfc front will settle south of the region tonight. Another impulse will support shower development along and north of the front across the SW third, with any activity being sct-isold. Diurnal heating with a conditionally unstable env may support shra/ts in the afternoon Tues. Otherwise, it will be slightly cooler with highs in the 70s and 80s. Deeper upper trough will settle into the Northern Plains Wed, supporting more chances for showers and storms as return flow ahead of the wave increases. The best chance for storms will be on the SD Plains, esp toward central SD where deeper moisture will reside. This area will also see the better chances for strong to severe storms given decent shear profiles. Upper trough will linger over the area Thur with cool conds and chances for showers per cold pool aloft. CAPE will be limited, hence not expecting any severe weather. Things will then dry out into the weekend with warmer temps. && .AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning) Issued At 514 AM MDT Mon Jul 1 2024 Scattered showers and thunderstorms are expected to form after 17-19z across NE WY and western SD. These storms will move eastward with time, with storm chances ending at KRAP after 23-00z this evening. Gusty, erratic winds will accompany any stronger cores along with MVFR/transient IFR conditions. Outside of thunderstorms, VFR conditions will prevail through the forecast period. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...JC AVIATION...SE