6/30 – Rob Martin’s “Cutting Into The Rain Deficit” Thursday Evening Forecast

Harrison County was the main recipient of heavy rain in the wee hours and past sunset this morning, with a wide swath of around 3” reported. We needed the rain but not the flooding issues. All areas have now cut into the rain deficit since the weekend, the heavy early-morning rain could repeat for Friday.

This very saturated air mass isn’t going anywhere over the next 3 days. Rain potential will spend a lot of time above that 70th percentile through the weekend. With disturbances remaining across the area, daily rounds of showers and thunderstorms are expected. No large scale forcing mechanisms, but with the moisture and instability available, we’ll get t-storm development.

With deep moisture and slow storm motions, expect some storms to be efficient rainmakers with rainfall rates in excess of 1-2″ per hour. Instantaneous rates will likely be significantly higher. This will continue to lead to a threat of locally heavy rainfall and localized nuisance or even flash flooding, and it’s not surprise that WPC keeps a daily marginal risk of excessive rainfall across the entire area through at least Friday.

As is typical in this kind of air mass, expect showers and storms to fire over the coastal waters overnight and into the morning hours, waning in those areas as the morning progresses. Over land, expect the best rain chances during the afternoon and early evening hours most places – the main exception being in coastal areas where marine storms could wander onto land in some areas. This pattern will continue through the Independence Day weekend and into early next week.