Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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714 FXUS63 KFSD 111101 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 601 AM CDT Sat May 11 2024 .KEY MESSAGES... - Temperatures continue to rise this weekend, breaking the 80 degree mark in a few areas Saturday, and most locations on Sunday. - Scattered thunderstorms will be possible Sunday afternoon and evening. Severe weather risks remain low, but gusty winds can`t be ruled out with a few storms. - Temperatures cool closer to seasonal normals next week with the coldest highs focused around Wednesday. - Rain chances increase again late Tuesday through Wednesday and then potentially Thursday into Friday. Severe weather risks remain low. QPF potential between 0.10 and 0.50". && .DISCUSSION... Issued at 238 AM CDT Sat May 11 2024 THIS MORNING: Skies remain mostly clear across the region, leading to perfect viewing conditions for a spectacular overnight northern lights display. Despite the light winds, temperatures remain in the upper 40s to lower 50s. Sheltered areas are likely to fall towards the lower 40s by daybreak. TODAY: A narrow band of mid-lvl clouds indicates the leading edge of low-mid lvl warm advection this morning. These clouds may try to slide northeast during the day as low-lvl temperatures at the 850 level rise between 11-14C through the day. We`ll mix into the higher end of the guidance this afternoon with widespread upper 70s to lower 80 high temperatures. An afternoon scattered CU field may again develop. Winds remain light, making Saturday one of those perfect Spring days to be outside. TONIGHT: Winds stay somewhat mixy overnight which will allow temperatures to remain in the lower 50s. An increase in mid-lvl clouds appears likely. SUNDAY: We may see an increase in cirrus overnight as upper flow trajectories turn to the northwest. At the surface a fairly weak and diffuse frontal boundary will drift towards the Tri-State area in the afternoon. Low-lvl temperatures again rise 3 to 4 degrees, which signals a strong potential for highs to climb into the 80s across the CWA. Weak surface convergence combined with subtle 700:500 vorticity advection may be enough to trigger widely scattered convection by mid-afternoon as convective temperatures are met. MLCAPE values remain fairly marginal given the poor return of surface dew points, but will likely end up in the 500 to 1000 J/KG. Mid-lvl lapse rates also remain marginal, so resultant soundings show fairly tall and thin CAPE profiles. Shear is also fairly weak, so no organization is expected. What may happen are typical Summer- time thunderstorms, with high cloud bases and deep inverted "V" soundings suggesting a greater risk for isolated downbursts than hail. Would expect this threat to remain very isolated however. MONDAY: An upper low moving across the Central and Southern Plains will likely draw moisture away from the Tri-State area Monday, with a greater chance of the area being influenced by cooler and drier Canadian air. Temperatures only rise towards the normal high around 70 degrees for this time of the year. TUESDAY-WEDNESDAY: Shortwave ridging moves east into the area Tuesday, keeping a light surface wind in the place in the morning. However by the afternoon in response to lee-side trough development, we`ll begin to see a shifting wind towards a southerly direction. Scattered convection developing over the western Dakotas and Nebraska Panhandle Tuesday evening will track slowly eastward overnight as an initial shortwave moves northeast across the Dakotas. With the front shoved eastwards for Wednesday, a secondary shortwave tracking a bit further south will likely allow renewed development for scattered showers and thunderstorms into Wednesday. At this point in time, instability looks rather meager Wednesday, with soundings showing moist adiabatic lapse rates throughout. The resultant QPF is also in the lower side, with ensembles focusing the highest probabilities within the 0.10" to 0.50" range. THURSDAY-FRIDAY: A deeper trough forming over southern Canada will keep the region into a progressive southwest to westerly flow pattern into the upcoming weekend. This may spell a continued risk for scattered rain into next weekend, along with temperatures a bit above normal. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 600 AM CDT Sat May 11 2024 A variable wind will turn west to southwest this morning, with occasional gusts to 15 to 20 mph this afternoon. VFR conditions are expected throughout the region today, with sounding suggesting the potential for high based CU this afternoon. Winds stay below 10 knots overnight, as cirrus moves across the region into Sunday morning. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Dux AVIATION...Dux