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#1003593 (Received by flhurricane at: 4:42 AM 05.Jun.2020)
TCDAT3

Tropical Depression Cristobal Discussion Number 15
NWS National Hurricane Center Miami FL AL032020
400 AM CDT Fri Jun 05 2020

Cristobal`s structure has continued to degrade since the last
advisory. Radar imagery from Sabancuy, Mexico shows little banding
near the center of the cyclone, though substantial convection is
still present in the northeast quadrant, over the Yucatan peninsula.
Earlier ASCAT data showed winds of 25-30 kt over the southern Gulf
of Mexico, and slightly stronger east-southeasterly winds over the
western Caribbean Sea. The initial intensity remains 30 kt, but it
should be noted that the highest wind speeds over land associated
with the circulation of Cristobal are likely lower.

Cristobal is forecast to remain over land for another 12 to 18
hours, and little change in strength is anticipated during that
time. Once the system moves over the Gulf of Mexico, gradual
strengthening still seems likely until Cristobal reaches the
northern U.S. Gulf Coast, and the NHC intensity forecast is largely
unchanged from the previous advisory.

The depression has completed a slow counter-clockwise loop and now
appears to be heading north-northeastward near 6 kt. The initial
position and motion are somewhat uncertain since the declining
structure of the cyclone makes it difficult to pinpoint a center
position at night. An upper-level trough to the west and a mid-level
ridge to the east of Cristobal are contributing to the deep
southerly flow that should steer the cyclone generally northward for
the next few days. All of the global models forecast this to occur,
though the exact forward speed at which Cristobal will move is more
uncertain. Overall, the 6Z guidance shows the cyclone moving
northward at a slightly faster pace and the NHC track forecast has
been adjusted accordingly. It now slightly lags the consensus but is
still faster than the ECMWF and the ECMWF ensemble mean.

Regardless of its exact track and forward speed, Cristobal is
expected to have a broad and asymmetric wind field as it approaches
the northern Gulf coast. The strongest winds, highest storm surge,
and heaviest rains could be well removed from the center of
circulation. Therefore, it is important that users do not focus on
the exact forecast path of the center of the cyclone.

Key Messages:
1. Damaging and deadly flooding was already occurring in portions
of Mexico and Central America. Cristobal is expected to produce
additional extreme rainfall amounts through the end of the week. The
heaviest additional rainfall is expected over far southern Mexico
and portions of the Yucatan Peninsula, while also extending along
the Pacific coast from Chiapas to Guatemala and El Salvador. This
rainfall could cause widespread life-threatening flash floods and
mudslides. Refer to products from your local weather office for more
information.

2. Cristobal is forecast to re-emerge over the southern Gulf of
Mexico later today and move northward over the central and northern
Gulf of Mexico over the weekend. There is a risk of tropical storm
force winds this weekend from Louisiana to the western Florida
Panhandle and a risk of dangerous storm surge from Louisiana to the
Florida Big Bend. These hazards will arrive well in advance of and
extend well east of Cristobal`s center. Storm surge and tropical
storm watches will likely be issued for a portion of the U.S. Gulf
Coast later today.

3. Heavy rainfall will spread into portions of the Gulf Coast from
east Texas to Florida this weekend into early next week, with areas
of flash flooding possible.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 18.8N 90.1W 30 KT 35 MPH
12H 05/1800Z 20.1N 90.1W 30 KT 35 MPH...INLAND
24H 06/0600Z 22.0N 90.3W 35 KT 40 MPH...OVER WATER
36H 06/1800Z 23.8N 90.4W 40 KT 45 MPH...OVER WATER
48H 07/0600Z 25.7N 90.3W 45 KT 50 MPH...OVER WATER
60H 07/1800Z 27.6N 90.4W 50 KT 60 MPH...OVER WATER
72H 08/0600Z 29.6N 91.2W 45 KT 50 MPH...INLAND
96H 09/0600Z 34.0N 92.5W 30 KT 35 MPH...INLAND
120H 10/0600Z 40.0N 90.0W 25 KT 30 MPH...INLAND

$$
Forecaster Zelinsky