Morning Hi-Res Visible / Sfc Obs / Front Analysis

[wxman57]

Just snapped a picture from last hour. I drew in where I think the frontal boundaries are. Note that the dew points across the middle isthmus of Mexico have dropped to the mid to upper 60s in the wake of the front. Quickscat shows the front fairly well, but keep in mind that the front is very, very shallow, and quickscat is looking just above the surface, so the frontal boundary on Quickscat will be west of the actual surface front:

http://manati.wwb.noaa.gov/storm_at_ima ... 3_90as.png

It's pretty clear that, despite what JB is saying this morning, that the low is still attached to the cold front. Now I can see signs that convection is starting to creep toward the center, indicating that it is gaining tropical characteristics slowly and attempting to separate from the front.. But look at that sub-50 degree air approaching the Gulf coast. Notice how the western part of the front is bulging south into west Texas and butting up against the mountains. That's what happens with cold air rushing down the Plains. It'll accelerate southward just east of the higher terrain. Such fronts may race south through central Texas and move off the lower TX coast before they reach the Houston area in southeast Texas. Since there are mountains just inland along the east coast of Mexico, the cold air has nowhere to go but straight south to the BOC. Since the flow is being restricted by mountains to the west, the air will accelerate to supergeostropic speeds (i.e., higher than the pressure gradient might suggest). That is why some rigs are reporting 40-50 mph westerly winds in the southern BOC.

Anyway, another shot of cold air will spill out across the Gulf tonight and be entrained into the BOC low tomorrow. That should help to intensify the low. So winds across the Gulf and BOC will be increasing. But cold air is not good for pure tropical development. Now the cold air advection will continue up until around mid-day on Friday, so it will be difficult for the low to disassociate itself from the front until maybe Saturday. That leaves a very narrow window of opportunity before an even stronger front arrives on Sunday. What will the low do?

There are two possibilities. One, it may stay in the SW Gulf/BOC on Saturday and be driven westward into Mexico, with perhaps a piece of the low tracking NE across Florida, producing another round of heavy rain ahead of the cold front on Sunday. I think that this scenario has about a 55-60% chance of happening.

The other scenario is that the low/storm/whatever in the BOC gets picked up completely by the digging trof on Saturday and it accelerates NE toward Florida, probably as a TS. I would see this storm having a hard time reaching hurricane strength due to tremendous wind shear across the central and northern Gulf (30+ kts). But I could see a sheared, comma-shaped TS tracking across Florida and possibly up the east coast just ahead of the front as JB is suggesting. I'm thinking that this scenario has about a 40-45% chance of happening.

So, there you have it. Recon is out there now taking another look. No doubt what they'll find wind-wise. Clearly, wind speeds are up to TS-strength north and west of the front/low in the cooler air. What will the NHC do....

Oh, here's the image:

<img src="http://home.houston.rr.com/wx/larry10.gif">

[Steve H.]

Good stuff...thanks.

[chris_fit]

Thanks!

[Stormcenter]

Good post wxman57.