Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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304 FXUS63 KDMX 101709 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 1209 PM CDT Fri May 10 2024 ...Updated for the 18z Aviation Discussion... .KEY MESSAGES... * A few showers and rumbles of thunder possible today. Elevated winds possible with showers/storms. * Possibly "top 10" spring day Saturday. * Shower/storm chances return Sunday PM, and additional opportunities through next week. && .DISCUSSION... Issued at 327 AM CDT Fri May 10 2024 Exiting shortwave trough has left in its wake quieter and drier conditions. With a relaxed surface pressure gradient and clear skies, a few areas, namely low lying areas and river valleys, have been able to develop fog. Not expected to become expansive as a drier air mass continues to slowly advect in. Today will see another shortwave trough traverse the region within the NW flow aloft, bringing with it additional chances for a few showers or rumbles of thunder. The core of this shortwave, and by virtue strongest lift, will be displaced further north and east than the one that passed through yesterday. Tied in with a drier near- surface air mass, and confidence in shower/storm chances and coverage is notably less. That said, HRRR/RAP soundings harken back to Tuesday with deep inverted-V soundings and elevated storm bases. Fortunately, shower/storm bases look to be on the order of about 5-6kft vs closer to 9kft on Tuesday, which allowed for more opportunity for evaporative cooling processes to accelerate showers to the surface. That said, would not find it unusual to see pockets of elevated winds with showers/storms that do develop. Otherwise generic thunderstorms. Saturday continues to look like a wonderful day, with top-10 potential. As the shortwave trough exits, surface ridging and light northwesterly winds combine to yield a day in the lower 70s with ample sunshine. A SW CONUS upper low begins to eject into the Plains Saturday, helping return shower/storm chances Sunday PM and into early next week. Deterministic and ensemble guidance remain in fair agreement in the overall path of the upper cut-off low, generally eastward across KS, but continue to differ in some of the detail. Euro and its ensemble cohorts tend to be displaced just a bit more southward with the upper low and are much more aggressive with dry air being ushered in from the Dakotas and Canada. Whereas the GFS/GEFS are displaced a bit more northward with the upper low and less aggressive with the dry air from the north. Suffice it to say precipitation chances return Sunday PM and linger through much of Monday, with greatest question in northern areas. Further into next week, additional chances for precipitation are seen mid-late week, but it remains difficult to really sharpen the broad NBM PoPs. Currently, it appears the greatest agreement is later Wednesday into Thursday with the GFS/GEFS faster than the Euro and its ensemble. Regardless, threat for severe appears low with lackluster forecast wind fields and thermodynamic profiles. | && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1208 PM CDT Fri May 10 2024 VFR conditions prevail through the TAF period. Isolated showers and storms are possible as a front pushes through the forecast area from northwest to southeast between 20z-02z. No mention of tsra was included for any terminal at this point due to the minimal coverage and low probability of impacts, however a tempo group may be necessitated as trends warrant to cover brief visby reductions and gusty winds. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Curtis AVIATION...Martin