Area Forecast Discussion
Issued by NWS Des Moines, IA

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039 FXUS63 KDMX 101932 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 232 PM CDT Fri May 10 2024 .KEY MESSAGES...
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- Isolated to scattered showers and storms later this afternoon and evening. Few strong wind gusts possible, but the severe threat is low. - Periodic rain chances next week, particularly Sunday night into Monday and again Wednesday into Thursday. Severe threat is low with early week activity, but becomes more uncertain toward the middle of next week.
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&& .DISCUSSION...
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Issued at 228 PM CDT Fri May 10 2024 GOES water vapor imagery denotes a compact shortwave diving southeast through Minnesota into Wisconsin. An attendant cold front was observed stretching from near Duluth and southwestward through northwest Iowa. This front will continue to sweep southeast and serve as the focus for isolated to scattered showers and storms later this afternoon and evening. Boundary layer moisture will be a significant limiting factor working against convective coverage and intensity. 19z surface obs show T-Td spreads approaching 25-30F and cloud bases above 6k feet. Inverted-v profiles beneath the cloud-bearing layer may favor sporadic stronger downburst wind gusts with any more robust updrafts, but overall the severe threat should remain low until storm chances exit south/east late this evening. Following a fantastic spring day on Saturday, chances for showers and storms are quick to return by later day Sunday as a closed upper low is nudged out of the four corners region and becomes more of an open and disorganized wave as it moves through the central Plains. Moisture is pulled northward and eventually begins competing with a drier airmass impinging from the north. This leads to some uncertainty on the northern extent of appreciable precip Sunday night through Monday, and higher chances have focused across southern and into central Iowa. Ensemble probs for >1" of precip are highest (~70%) close to the MO border with diminishing precip amounts to the north. Any severe threat should be mitigated by lethargic flow aloft and limited instability. Mean northwesterly flow aloft dominates through the middle part of next week as our pattern remains fairly active with additional opportunities for more rainfall. Precip chances return by late Tuesday as an upper wave dives southeast out of Canada. Periodic precip chances are then supported through the remainder of the forecast as another nearly closed low in the split southern stream flow is absorbed by the mean northern branch. The severe weather threat is in questions through the middle of the week due to uncertainties with the northerly extent and quality of moisture return off the Gulf of Mexico and the timing of the respective upper waves crossing the region.
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&& .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...Martin AVIATION...Martin