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FXUS63 KDMX 200444 AFDDMX

Area Forecast Discussion National Weather Service Des Moines IA 1144 PM CDT Sun May 19 2024


Updated for the 06z Aviation Discussion

KEY MESSAGES

- Active pattern to persist through early next week with multiple rounds of thunderstorms, some of which may be severe

- Tuesday carries the most widespread and high impact severe weather potential with widespread Enhanced Risk (3/5)

- Storms will likely be accompanied by heavy rain through Tuesday as moisture increases

DISCUSSION
Issued at 247 PM CDT Sun May 19 2024

Progressive pattern continues through early this week with multiple shortwave troughs lifting northeast across IA.
Periodic thunderstorms will be the result with varying severe weather threats, some of which will depend upon overnight convection and the impact on insolation/instability.

Elevated storms have been pesky today, maintaining for longer and stronger than most models had indicated. The more organized updrafts have hugged a MUCAPE gradients thats draped across southern IA. Convection has been isolated and weaker elsewhere.
Expect this trend to continue for the remainder of the afternoon. Looking upstream, satellite clearly depicts next shortwave accelerating across the high plains, with convection erupting in advance. This shortwave tracks across the state later today and overnight, providing the next potential (this evening) for severe convection give sufficient deep layer shear and instability. Thunderstorms will linger through the overnight; although severe threat decreases later this evening.

Shortwave trough moves east of the CWA on Monday morning, likely providing a relative minimum in storm chances immediately in its wake, sometime around midday. Even so, surface boundary will remain draped across the state and when combined with SBCAPE values of 2000-2500 j/kg will provide the potential for another round of afternoon/early evening convection. Coverage/strength will depend on how quickly the morning shortwave departs and how much destabilization can occur behind.

Attention then shifts to Tuesday as the strongest shortwave of the period takes aim on the Midwest during diurnal heating.
Latest guidance tracks the surface low pressure into NW IA or S MN by mid-afternoon. Parameters are progd be more than sufficient for severe in the warm sector with SBCAPEs progd 3000+ j/kg and deep layer shear of 50-60 knots. There is some questions on timing and location of synoptic features, which will dictate where storms initiate and resultant impact on severity. As always, the devils in the details, which will become more clear in the next 24-36 hours.

The system departs quickly Tuesday night, giving way to a couple of drier days on Wednesday and Thursday. More storm chances returning by the end of the week.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
Issued at 1144 PM CDT Sun May 19 2024

A line of showers and storms continues east of I-35 early this morning and is expected to move out of the area over the next few hours. However, a large cluster of additional showers and storms are expected to lift north across the state after 06z, which will allow for active weather to continue through much of the morning. Periods of lower ceilings and reduced visibilities from heavier rainfall with these storms may allow for MVFR conditions at times. A drying period looks to occur by late morning through the afternoon, before additional showers and storms look to move into the area towards the evening. Specific mention of timing and location of storms Monday evening remain unclear and will largely depend on the previous storm evolution, which will be monitored closely. Winds will gradually shift south/southwesterly with slightly breezy winds through the daylight hours.

DMX WATCHES/WARNINGS/ADVISORIES
None.

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Des Moines, IA,