Some models and even local meteorologists up the Texas and Louisiana coasts tonight are talking about possible cyclone development; I emphasize possible strenuously. To my knowledge none are predicting a tropical storm; certainly not a hurricane. So, what is going on that has people talking?
The Hydrometeorological Prediction Center (HPC) – those guys that issue storm advisories after hurricanes made landfall – is pinpointing somewhat they’re ideas for what may be occurring going into the weekend.
The image below is a surface forecast three days out from the HPC. Notice the surface low off Brownsville, Texas.
This stems from a front dipping down from the northeast along a trough currently situated over the northern Gulf. By Sunday morning, the HPC has moved the low into the Galveston/Port Arthur, Texas region.
The National Weather Service outside of Houston has some interesting comments on the situation earlier:
REGARDING THE NAM12 [SOLUTION]…THE LAST SEVERAL RUNS HAVE SHOWN A [SURFACE] LOW DEVELOPING AND DEEPENING OUT NEAR BUOY 42002 BEGINNING TOMORROW [AFTERNOON]/[EVENING]. IT`S NOT TOTALLY OUT OF THE RANGE OF POSSIBILITY CONSIDERING ALL THE MODELS ARE SHOWING A TEMPORARY WEAKENING OF THE SHEAR ALOFT AT THAT TIME OFF THE TX COAST. BUT THEY ALSO INCREASE IT AGAIN EARLY FRI. MAJORITY OF THE MODELS DO SHOW VARIOUS CIRCULATIONS BETWEEN NOW AND THE WEEKEND…MOST OF WHICH ARE USUALLY SPURIOUS OR SHORT LIVED CONVECTIVELY INDUCED IN SUCH A PATTERN WE ARE UNDER. THAT BEING SAID THIS IS TYPICALLY THE PEAK WEEK OF HURRICANE SEASON SO WILL NEVER RULE ANYTHING COMPLETELY OUT…BUT HAVE A FEELING THE NAM12 IS OVER DEVELOPING THAT FEATURE BUT HAVE SEEN WEIRDER THINGS OCCUR. WILL JUST HAVE TO WATCH.
So, essentially what they are saying is: Yes, some models are showing some type of surface circulation. But, they’re not consistent. So, we’ll watch it but we’re not concerned.
Yet.
Buoy 420002 referred to is 200 miles east of Brownsville. Pressure in that area is currently 1012mb and steady. That’s about average for tropical cyclone development. What it does show to a small extent is an unstable airmass created in large part between the trough along the northeast Gulf coast and an area of scattered showers in the southern Gulf in the Bay of Campeche.
In addition, shear is expected to remain intense for tropical cyclone development as it has all season in the Gulf.
So, essentially what we have is a possibility of a developing low pressure system off the south Texas coast. Most of the models agree that should this occur it will move mostly northward – perhaps east of north – along the Texas coast into southeast Texas or Louisiana. The question will be how well does it organize. Considering this will be a hybrid system transitioning from a cold-core low to a warm-core low this is a time-consuming process that the system just won’t have. At best it would be a disorganized subtropical storm bringing heavy rains to areas north and east of the system. This is also provided the shear remains pretty intensive throughout the weekend as expected. So, in addition, it’s a low to mid-level system.
Again, this is hypothetical as of right now. But, I wanted to go ahead and point out something that seems to be getting some steam and what the most-plausible scenario is for development.
In summary, should low develop, expect it to be a shallow hybrid system bringing torrential rains and perhaps small coastal flooding. However, there should be no chance of the system ramping up to anything beyond a medium-strength tropical storm.
