May 21st Forecast

Low level clouds and fog from this morning will clear out by noon, leaving clear skies west of the dry line, which will be located east of I-35. There is a chance of afternoon convection initiating along this line between 18-21 UTC, but any measurable precipitation will be to the east of the MC3E domain.

The dryline return west overnight on Saturday night. Convection may initiate along the dryline in the afternoon. While first echoes may be along I-35, any measurable precipitation will be to the east of I-35, and low level moisture is not favorable in the MC3E domain.

Earlier model runs had an additional line of precipitation developing behind the first line of afternoon storms. This area lasted through the night and was still raining over the central facility on Monday. While low level moisture doesn't look favorable at this point, this looks similar to the event last Thursday-Friday, when a line of supercells developed on the dryline, moved east, and then another line of storms developed late in the night and merged into a large MCS, which moved through central Oklahoma on Friday morning. The models did not forecast that scenario well.

A negatively-tilted trough moving on to the west coast will begin to bring more favorable upper level dynamics beginning Monday. A series of shortwave troughs will move across Oklahoma, bringing waves of precipitation. Timing is uncertain right now, as both the GFS and NAM contain entirely different solutions, but convection is likely in the afternoon, beginning between 18-21 UTC. Current NAM run shows increasing coverage and intensity between 21-00 UTC.

As the next trough moves across the country, Tuesday and Wednesday will be very unsettled. Precipitation of varying intensity is expected on both days. The bulk of the moisture should be far enough to the east on Thursday to limit convective development.