Tropical Depression Fourteen Advisory Number 1
NWS National Hurricane Center Miami FL AL142020
1100 AM EDT Thu Aug 20 2020
...TROPICAL DEPRESSION FORMS OVER THE WEST-CENTRAL CARIBBEAN SEA...
...TROPICAL STORM WATCH ISSUED FOR PORTIONS OF HONDURAS...
SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.1N 79.7W
ABOUT 235 MI...375 KM E OF CABO GRACIAS A DIOS ON NIC/HON BORDER
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 21 MPH...33 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
The government of Honduras has issued a Tropical Storm Watch for
the coast of Honduras from the Honduras/Nicaragua border westward
to Punta Castilla and for the Bay Islands of Honduras.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Watch is in effect for...
* Honduras/Nicaragua border westward to Punta Castilla Honduras
* Bay Islands of Honduras
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, in this case within the next 36
hours.
Additional watches or warnings, including for the Yucatan Peninsula
of Mexico, may be required later today.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND OUTLOOK
----------------------
At 1100 AM EDT (1500 UTC), the center of Tropical Depression
Fourteen was located near latitude 15.1 North, longitude 79.7 West.
The depression is moving toward the west near 21 mph (33 km/h), and
a westward motion is expected to continue through this evening. A
turn toward the west-northwest and northwest with a decrease in
forward speed is forecast tonight and Friday, with a general
northwest motion continuing through at least Sunday. On the
forecast track, the center of the system will move near or just
north of the northeastern coast of Honduras and the Bay Islands on
Friday and will approach the east coast of the Yucatan Peninsula of
Mexico on Saturday. The center is then expected to cross the
Yucatan Peninsula Saturday night and move into the south-central
Gulf of Mexico on Sunday.
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Strengthening is forecast during the next couple of days, and the
depression is expected to become a tropical storm later today or
tonight. The system could be near or at hurricane strength when it
reaches the Yucatan Peninsula of Mexico late Saturday.
The estimated minimum central pressure is 1007 mb (29.74 inches).
HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible within the watch
area tonight and on Friday.
RAINFALL: The depression is expected to produce 1 to 2 inches
of rain across Jamaica and northern Nicaragua, and 2 to 4 inches
over portions of Honduras through Saturday.
NEXT ADVISORY
-------------
Next intermediate advisory at 200 PM EDT.
Next complete advisory at 500 PM EDT.
$$
Forecaster Berg
Tropical Depression Fourteen Discussion Number 1
NWS National Hurricane Center Miami FL AL142020
1100 AM EDT Thu Aug 20 2020
Visible satellite images indicate that the area of disturbed
weather moving across the central Caribbean Sea has developed a
closed surface circulation, with the center embedded beneath
cellular convective cells and a large cirrus canopy. Also,
convection has increased in organization, and TAFB and SAB have
given the system classification of T2.0/30 kt and T1.5/25 kt,
respectively. Therefore, advisories are being initiated on
Tropical Depression Fourteen with maximum winds of 30 kt. An
expected ASCAT pass later today and an Air Force Reserve Hurricane
Hunter mission scheduled for this afternoon should give us a better
handle on both the depression's center location and its maximum
winds.
The depression continues to move westward at a pretty good clip,
currently estimated to be on a heading of 280 degrees at 18 kt.
This motion is being driven by the western extent of the Bermuda
high, which currently noses into the northwestern Caribbean Sea.
However, a deep-layer trough over the Gulf of Mexico is expected to
become the main driver in the coming days, causing the cyclone to
slow down and turn rather suddenly toward the west-northwest and
northwest in the next 24-36 hours. A general northwestward motion
should then continue until the end of the 5-day forecast period,
bringing the system across the Yucatan Peninsula Saturday night and
into the central and western Gulf of Mexico early next week. Most
of the reliable track models are clustered close to one another,
and the official NHC track forecast is therefore very close to the
multi-model consensus aids, including the HCCA model.
Once the depression slows down during the next 24-36 hours,
environmental conditions appear ideal for strengthening. The
magnitude of vertical shear is expected to be less than 10 kt for
at least the next 2 days, while the system will be moving over the
deep, warm waters of the northwestern Caribbean Sea, where sea
surface temperatures are 29-30 degrees Celsius. Given these
conditions, some of the intensity guidance actually appears more
muted than I would have expected, and I have therefore elected to
closely follow the SHIPS and LGEM models, which are near the upper
end of the guidance envelope. It is possible that the depression
could be near or at hurricane strength when it approaches the
Yucatan Peninsula of Mexico in 2-3 days. Some weakening is
anticipated when the center moves over land, and then
re-strengthening is likely after it moves over the Gulf of Mexico.
There will be an increase in shear over the Gulf in 4-5 days, and
right now there is greater-than-normal uncertainty in how this will
affect the cyclone's intensity at that point. For now, the
official forecast on days 4 and 5 shows a flat-lined intensity, and
this scenario lies a little above the ICON intensity consensus and
the HCCA model solution.
Key Messages:
1. Tropical Depression Fourteen is expected to strengthen over the
northwestern Caribbean Sea through Saturday, and it could produce
tropical-storm-force winds and heavy rainfall over portions of the
coast of Honduras and the Bay Islands beginning tonight through
Friday. The system could be near or at hurricane strength when it
reaches the Yucatan Peninsula of Mexico late Saturday, and watches
could be required for a portion of that area later today.
2. The system is expected to move into the south-central Gulf
of Mexico as a tropical storm on Sunday. Some strengthening is
anticipated while it moves northwestward over the western Gulf of
Mexico early next week, but it is too soon to know exactly how
strong it will get or the location and magnitude of impacts it
will produce along the central or northwestern Gulf Coast.
Interests in that area should continue monitoring the progress of
this system over the next few days.
FORECAST POSITIONS AND MAX WINDS
INIT 20/1500Z 15.1N 79.7W 30 KT 35 MPH
12H 21/0000Z 15.5N 81.9W 35 KT 40 MPH
24H 21/1200Z 16.3N 84.2W 40 KT 45 MPH
36H 22/0000Z 17.1N 85.5W 50 KT 60 MPH
48H 22/1200Z 18.4N 86.4W 55 KT 65 MPH
60H 23/0000Z 19.9N 87.4W 60 KT 70 MPH
72H 23/1200Z 21.5N 88.9W 45 KT 50 MPH
96H 24/1200Z 25.0N 92.0W 50 KT 60 MPH
120H 25/1200Z 28.0N 94.0W 50 KT 60 MPH
$$
Forecaster Berg