Tropical Threat Here Next Weekend ?

I just hate Octobers that act like September - and we seem to get more than our share of them. I desperately want to get on with fall, get some 50 degree nights and be done with hurricane season, but folks it’s not happening for another two weeks. Worse still, chances are good that a tropical depression will form in the SW Gulf late Wednesday or early Thursday. This could impact Louisiana with more possible heavy rain and tidal (coastal) flooding due to a stiff onshore breeze. Yes, it could become a named storm. We’ll discuss that in the Long-Range Ramblings section.

The good news is that the worst of the rain is over. This IR satellite image shows the heavier storms in the Gulf south of Mississippi and near Mobile but some lingering showers west of us that could give us a few more tenths of an inch tonight. Monday will be better, but not rain-free. Then, we’re in for 3-4 days of seasonably nice weather with sun from Tuesday afternoon through Thursday before the weekend “fun” begins.

The Foreca graphic starts with the dwindling rain chances tomorrow (either pre-dawn or 30% light afternoon showers) with partly cloudy skies. Tuesday - Thursday should see more sun than clouds. I think the graphic overdoes the cloudiness on Thursday. The air will feel somewhat less humid with morning lows in the mid 60s in most rural areas and highs mid 80s. Clouds roll in on Friday, then wind and humidity pick up on Saturday before the next system rolls in sometime during the weekend or next Monday. Though I wouldn’t take it to the bank yet, notice the heavy rain amounts. Like Bob Breck was fond of saying, it all depends on the Gulf.

Models are sensing that a depression is about to happen in the SW Gulf. This afternoon’s visible image shows clouds plunging south in Mexico while a tropical push from the opposite direction is taking place just offshore (See arrows — I wish I could show animation). Rotation will eventually take place because of Mr. Coriolis and voila, by mid-week a depression will form.

The sea surface temperatures are plenty warm enough and south of the border the wind shear is light, so this has potential to develop. But because we don’t know exactly where this will form and the fact that Mexicans send up upper air balloons sparingly, models are all over the place. Some wobble the center around and eventually take them into Mexico. Others take the depression as more of a trough north to West Central Louisiana where it would give us a lot of rain, while one develops them into a Cat. 1 hurricane headed straight for us (There, I said it - but take comfort in the fact that it’s the “I overdo everything” American GFS model that does this).

Suffice it to say that I’ll be watching this and will probably give you daily updates as long as its a threat to us. The big determining factor will be wind shear. The ocean heat content (temperatures in the entire upper layer, not just the surface) are hottest 100 miles south and east of the mouth of the MS river. If the storm would develop and go near there, va voom, but I’m getting ahead of myself.

We’re in a wait and see posture and tomorrow may not bring much additional clarity. When something starts to develop and they fly into it, models can do magical things — until then — Goodnight.

Foreca graphic for Pensacola Beach paints a very similar picture. I think whatever develops in the Gulf will come closer to us in LA and MS than Pensacola, but they will still get the rain and wind.