Shower chances go up this weekend

Last night’s storms put on more of a show than the one I saw in Sandestin on the Fourth. I expected storms would break out early today, but my thinking was more like 10 AM than 1 AM. Upper level winds were anemic, so the storms went nowhere while dumping a quick inch or two in one location before fizzling out while nearby locations received much less. However, they certainly overachieved electrically.

Weather tomorrow through Thursday will be typical summer with 20% chance of afternoon and evening pop-up showers and storms — less of a chance than today. Again, with little movement, a few inches in one spot is not out of the question though most of us will get zilch. For example, the Weather Service issued a Flash Flood Warning late this afternoon for most of the Southshore when a storm dumped a quick 2”. I believe they overreacted because of fear of pumping failures. For the next few days….WE ARE IN NO DANGER OF PICKING UP A 6” plus AMOUNT like June 18.

However, starting Friday evening and continuing on through Monday, a plume of tropical moisture aloft will reach us from the Western Gulf. Here’s a product that I haven’t shown you before — forecast total water vapor in the atmosphere over you. The red color showing the higher amounts are mainly confined to the Southern Gulf tonight (left side), but will wrap itself around the Gulf to engulf us by Sunday evening (right side). More moisture aloft means an increase in shower chances and amounts starting Friday evening and then both Saturday and Sunday afternoon/evening.

But the best chance for heavy rain will probably be Monday when a frontal trough presses southward to provide some extra lift to the tropical stew. This is an ECMWF Artifiical Intelligence model forecast for Monday showing a frontal trough aloft just north of us moving in our direction (at this time of year, fronts often show up better off the surface).

The Foreca graphic perhaps overdoes the rainfall on Thursday, but the big picture is correct in showing a general increase in shower activity from Friday evening on. This first happens in the afternoon and evening hours over Friday and Saturday, then almost anytime on Monday and Tuesday. Highs are inversely related to shower chances with the higher chances lowering the highs.

In terms of where the showers and storms will occur, chances are slightly higher on the Southshore and in Western St. Tammany/Tangipahoa tomorrow and Thursday — maybe 30% vs. 20%. Otherwise, your guess is as good as mine.

After a wet period at the beginning of next week, models are forecasting a dry period from July 16 to 21. The tropics are quiet and are likely to remain so for another week or two.

El Nino forecasts are becoming more extreme and that seems quite reasonable given buoy data from the tropical Pacific. This means the chances of any hurricane or tropical storm developing in the traditional regions — east of the Antilles, the Caribbean, or Southern Gulf are practically zero. Any developments would be further north, north of the Bahamas, east of the Carolinas, near Bermuda, or the Central Atlantic out to the Azores. Yes, it’s possible something could develop right offshore from us but it wouldn’t have a lot of time to develop and upper level winds would push it east. The heart of the season begins in a month.

Foreca graphic for Pensacola Beach shows nice weather with widely scattered showers and storms today through Friday. Storm chances pick up over the weekend through next week. Highs low 90s drop to the 80s by Monday.