Tropical Weather Discussion

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Tropical Weather Discussion (NHC/TPC):
NWS National Hurricane Center Miami FL
205 AM EDT Thu Jul 09 2020

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through 
0530 UTC.


Surface observations, satellite data, and radar data indicate 
that an area of low pressure, that is  about 50 miles to the 
east of Wilmington in North Carolina, gradually is becoming better 
defined. The associated rainshowers and thunderstorms still are 
disorganized. They are mostly confined to the east of the center. 
The low pressure center is expected to move northeastward or north-
northeastward, near or just offshore of the North Carolina Outer 
Banks later today, and then along the mid-Atlantic coast tonight and 
Friday. Environmental conditions are expected to be conducive for 
development. It is likely that a tropical cyclone or subtropical 
cyclone may form later today or tonight. The system is expected to 
produce locally heavy rainfall that may cause some flash flooding in 
parts of eastern North Carolina, the coastal mid-Atlantic, and 
southern New England during the next few days. Gusty winds also are 
possible along the North Carolina Outer Banks today, and along the 
mid-Atlantic and southern New England coasts Friday and Saturday. 
Please monitor the progress of this system, and refer to bulletins, 
and watches and warnings from your local National Weather Service 
office. An Air Force Reserve Hurricane Hunter aircraft is scheduled 
to investigate this system later today, if necessary.
The chance of formation into a tropical cyclone, during the next 48 
hours, is high. Please read the Tropical Weather Outlook, at, for more details.


An Atlantic Ocean tropical wave is along 19N38W 10N41W 01N42W, 
moving westward 10 knots. Saharan air and an associated low level 
wind surge have moved well ahead of this wave, and can be seen from 
10N to 22N, from Lesser Antilles eastward. Precipitation: this wave 
is moving through the ITCZ, with the ITCZ's associated precipitation.

A Caribbean Sea tropical wave is along 22N66W 14N68W 03N69W, moving 
westward 10 to 15 knots. Precipitation: widely scattered moderate to 
isolated strong is within 300 nm to the north of the easternmost 
sections of the Dominican Republic on the Atlantic Ocean side. This 
precipitation also is in the area of upper level cyclonic wind flow 
with a trough.

A Caribbean Sea tropical wave is along 78W/79W, from 21N 
southward, moving westward 10 to 15 knots. Precipitation: widely 
scattered to scattered moderate and isolated strong is in the 
coastal plains of and coastal waters of Cuba from 80W 
southeastward, and from 12N in Nicaragua to 17N between 77W in 
the Caribbean Sea and the western coast of Nicaragua.

A tropical wave is along 90W/91W, from 19N in the Yucatan 
Peninsula southward, moving westward 10 to 15 knots. 
Precipitation: isolated moderate to locally strong is in the SW 
corner of the Gulf of Mexico, from 22N southward from 90W 

The monsoon trough passes through the coastal areas of 
Guinea-Bissau near 12N16W, to 10N26W, 10N38W, 06N45W, and 
06N48W. The ITCZ continues from 06N48W, to 06N54W, and 07N58W 
along the coast of Guyana. 
Precipitation: scattered moderate to strong is from 09N to 11N 
between 22W and 25W, and from 05N to 08N between 31W and 36W. 
Isolated to widely scattered moderate and locally strong is 
elsewhere within 200 nm on either side of the rest of the 
monsoon trough from 36W westward, and the entire ITCZ.


A 1015 mb high pressure center is near 26N87W. Broad surface 
anticyclonic wind flow covers the Gulf of Mexico.

An upper level cyclonic circulation center is in the SW corner 
of the Gulf of Mexico. An inverted trough extends from the north 
central Gulf of Mexico to the cyclonic center. 

An upper level ridge extends from NW Mexico, to the upper Texas 
Gulf coast, to the NE Gulf of Mexico, and southeastward, across 
Florida to the NW Bahamas. 

Surface high pressure will remain centered in the Gulf of Mexico 
through the weekend, with the high pressure center fluctuating 
between the NW part and the NE part of the basin. This will allow 
for the continuation of moderate to fresh return flow to the west of 
90W, and moderate westerly winds across NE parts of the basin. 
Scattered rainshowers are forecast for the NE and SE sections of the 
basin on Friday and Saturday, associated with low pressure center 
that is along the coast of North Carolina, that extends 
southwestward into the area.


The GFS model shows that upper level cyclonic wind flow covers 
the Caribbean Sea, from 250 mb to 700 mb, from Haiti westward. 
One tropical wave is along 78W/79W, and a second tropical wave 
is along 90W/91W.  

The monsoon trough is along 09N/11N between 74W and beyond Costa 
Rica. Precipitation: scattered to numerous strong covers the 
areas from 08N to 11N between the western edges of Lake 
Maracaibo in NW Venezuela to 74W in Colombia. Scattered moderate 
to strong is within 60 nm to the north of the monsoon trough 
between 80W and 82W in the SW corner of the Caribbean Sea.

Atlantic Ocean high pressure, that extends to the northern 
Caribbean Sea waters, will allow the continuation of fresh to 
strong trade winds in the south central Caribbean Sea, increasing to 
near gale-force on Friday and Saturday nights. Freshening winds, 
building seas, and active weather accompanying a strong tropical 
wave along 77W will shift W across the basin through Friday. Strong 
winds will pulse at night in the Gulf of Honduras from Friday night 
through the weekend. Another strong tropical wave will reach the 
tropical N Atlantic Ocean on Saturday, and it will move across the E 
Caribbean Sea on Saturday night and Sunday.


Cyclonic wind flow, and a developing trough, cover the Atlantic 
Ocean from the NW Bahamas northward, from the surface to 500 mb. 
An upper level trough extends from a 29N62W cyclonic circulation 
center, southwestward, to the SE Bahamas and eastern Hispaniola. 
Precipitation: widely scattered moderate to isolated strong 
covers the Atlantic Ocean from 20N northward from 60W westward. 
Isolated moderate is from 26N northward between 45W and 60W, 
related to lingering weak surface-to-low level cyclonic wind 

Low pressure, that is along the coast of SE North Carolina, extends 
southward as a surface trough, across the waters that are to the W 
of 70W. Scattered rainshowers and thunderstorms that are  associated 
with this elongated area of low pressure will continue to affect the 
waters E and N of the Bahamas through the weekend. A surface ridge 
will dominate the remainder of the waters E of 70W. The pressure 
gradient between the low pressure and the ridge will support 
moderate to fresh winds across most of the region, increasing to 
fresh to strong winds N of the Bahamas during the weekend. 

Graphical representation of waves, etc. on this image (NCEP/OPC) [more].
Various tropical satellite imagery available here

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