Tropical Update: Invest 91L Gradually Organizing; Hurricane Hunters Scheduled to Investigate This Afternoon

Invest 91L is gradually organizing in the Bay of Campeche.

Analysis

Convective activity remains disorganized. However, vorticity has increased, with broad cyclonic turning evident.

Wind shear also remains low in the vicinity of 91L per the most recent wind shear analysis from CIMSS.

Model guidance

As of the 00z model cycle, both the ECMWF and GFS continued to predict development of Invest 91L, while the UKMET dropped the idea of development.

The ECMWF predicts development of a tropical depression by late tomorrow; strengthening to a low-end tropical storm by late Tuesday; landfall near Tampico, Mexico followed by a north/northeast track along the Texas Gulf Coast Wednesday and Thursday.

The GFS predicts development of a tropical depression by tomorrow morning; landfall north of Tampico, Mexico late Tuesday; absorption by an upper-low after landfall.

Additionally, there continues to be strong ensemble support for development from the EPS, GEFS and GEPS.

Many EPS members also continue to advertise a turn north and then northeast up the western Gulf Coast.

Development potential

91L still has a decent chance of developing over the next day or two.

In their 8 AM EDT Tropical Weather Outlook, the National Hurricane Center gave 91L a 60% chance of developing over both the next 2 days and 5 days.

A USAF reconnaissance aircraft is scheduled to investigate this afternoon.

Potential track and intensity

Track: The track forecast is no longer as clear as originally thought.

There are now three different possible track scenarios on the table.

1) A northwest track with landfall along the northern Mexico Gulf Coast Tuesday/Wednesday.

2) A northwest track with brief landfall along the northern Mexico Gulf Coast Tuesday/Wednesday, followed by a turn to the north/northeast Wednesday/Thursday. The turn could result in reemergence over the Gulf and a track toward TX/LA or a track just inland of TX/LA.

3) A northwest track through Tuesday/Wednesday with no landfall, followed by a turn to the north/northeast toward Texas and Louisiana late Wednesday/Thursday.

The speed of an upper-level low set to move into the Plains late this week will determine what track 91L ends up taking.

If the upper-low is faster, it would favor scenario 2 or 3. Conversely, if the upper-low is slower, it would favor scenario 1.

Unfortunately, it is impossible to say which is more likely at this juncture.

Intensity: It is still unlikely that 91L will become too strong should it develop.

Direct impacts for U.S. Gulf Coast less certain

U.S. impacts will be highly dependent on the track of 91L.

Obviously, if track scenario 2 or 3 were to come to fruition, there would be direct impacts for Texas and Louisiana.

Regardless of development and track, Invest 91L, in conjunction with the aforementioned upper-low, will enhance rainfall across Texas and Louisiana toward the end of the week.