Tropical Storm Alberto Discussion Number   8
NWS National Hurricane Center Miami FL       AL012024
1000 AM CDT Wed Jun 19 2024

Dropsonde data from an Air Force Reserve reconnaissance aircraft
and NOAA buoy 42055 in the southwestern Gulf of Mexico indicate
that the system has developed a well-defined center of circulation.
In addition, deep convection has formed near the center, as well as
within a band extending 200 n mi to the southeast of the center.
This convection is classifiable via the Dvorak technique.  The
system meets the necessary requirements of being a tropical cyclone
and is therefore being designated as Tropical Storm Alberto.
Aircraft and surface observations suggest the maximum winds remain
about 35 kt, but the central pressure has dropped to about 995 mb
according to the dropsonde data.  Some of the dropsonde and oil
rig data in the northwestern Gulf indicate that stronger winds are
located not too far above the ocean surface, but the environment
appears too stable for sustained winds of that magnitude to mix
efficiently down to the surface.  Still, this could mean that gusty
winds affect much of South Texas as the convective activity moves
inland through the day.

Alberto may have jogged a bit south now that a more defined center
has become apparent, but the general motion remains westward, or
270/8 kt.  This westward motion is expected to continue for the
next day or two while mid-level ridging over the eastern U.S.
builds westward, and the track models all agree that the center of
Alberto should be inland over northeastern Mexico by this time
Thursday morning.

Alberto has a chance to strengthen within a favorable environment
of low vertical shear and warm sea surface temperatures of about 30
degrees Celsius.  However, the broad circulation will still likely
limit the amount of strengthening that can occur, and the NHC
forecast continues to show a peak intensity of 40 kt before the
storm reaches land.  There is some possibility of slight
strengthening beyond that level, as suggested by the GFS and HAFS-B
models.  After landfall, rapid weakening is forecast on Thursday.
A 36-hour forecast point as a remnant low is shown mostly for
continuity, but in all likelihood the system will have dissipated
over the mountainous terrain of Mexico by then.

Regardless of Alberto's exact track, this system will have a large 
area of heavy rains, moderate coastal flooding and 
tropical-storm-force winds well north of the center.  Importantly,
the official wind speed probabilities are likely underestimating the
chances of tropical-storm-force winds along the Texas coast because
of the unusually large and asymmetric area of strong winds on the
northern side of the circulation.


Key Messages:

1. Users are reminded not to focus on the exact forecast track of
this system.  Alberto is very large with rainfall, coastal flooding, 
and wind impacts likely to occur far from the center along the 
coasts of Texas and northeastern Mexico.

2. Heavy rainfall associated with Tropical Storm Alberto will impact 
large regions of Central America, north across northeastern Mexico 
and into South Texas. This rainfall will likely produce considerable 
flash and urban flooding along with new and renewed river flooding. 
Life-threatening flooding and mudslides are likely in and near areas 
of higher terrain across the Mexican states of Coahuila, Nuevo Leon, 
and Tamaulipas, including the cities of Monterrey and Ciudad 
Victoria.

3. Moderate coastal flooding is likely along much of the Texas
Coast through Thursday.

4. Tropical storm conditions are expected today along portions of
the Texas coast south of San Luis Pass and along portions of the
coast of northeastern Mexico within the Tropical Storm Warning area.


FORECAST POSITIONS AND MAX WINDS

INIT  19/1500Z 22.2N  95.0W   35 KT  40 MPH
12H  20/0000Z 22.2N  96.4W   40 KT  45 MPH
24H  20/1200Z 22.3N  98.3W   40 KT  45 MPH...INLAND
36H  21/0000Z 22.4N 101.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
48H  21/1200Z...DISSIPATED

$$
Forecaster Berg