AXNT20 KNHC 232348

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
748 PM EDT Sun Jul 23 2017

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 1800 UTC surface analysis and satellite imagery through 2345 UTC.


A tropical wave is in the east Atlantic with axis extending from 16N24W to 05N24W, moving west at 15 kt within the last 24 hours. Both CIRA LPW and SSMI TPW imagery confirms the extensive presence of the dry air mainly in the northern wave's environment. Shallow moisture associated with the African monsoon along with upper-level diffluence support scattered showers south of 10N between 20W-30W.

A tropical wave is in the central Atlantic with axis extending from 19N35W to 09N36W, moving west at 5-10 kt within the last 24 hours. The wave is in a region where Saharan dry air and dust prevail hindering deep convection at the time.

Another tropical wave is in the central Atlantic with axis extending from 16N50W to 06N51W, moving W at 10-15 kt within the last 24 hours. The wave is in a region where Saharan dry air and dust prevail. Isolated showers are observed along the wave's axis near 12N between 49W-52W.

A tropical wave is in the far west Caribbean and Central America. The wave's axis extends from 20N87W to 08N87W. TPW imagery depicts abundant moisture in the environment of this wave. With this and a diffluent flow aloft are generating scattered moderate convection from 14N-19N and west of 83W affecting The Yucatan Peninsula, Belize, Honduras, El Salvador, and adjacent waters.


The monsoon trough axis extends from 14N17W and continues along 10N25W to 13N38W to 10N54W. The ITCZ begins near 10N52W and continues to 10N62W. For information about convection, see the Tropical Waves section above.



Weak surface ridging dominates across the Gulf waters anchored by a 1019 mb high centered near 26N85W. With this, light to gentle anticyclonic winds prevailing across the basin. Instability aloft supports scattered showers across the northeastern portion of the basin mainly north of 27W and east of 90W. Similar activity is also over the Florida Peninsula. Expect during the next 24 hours for a similar synoptic pattern to continue. A thermal trough will move west from the Yucatan Peninsula into the Bay of Campeche with convection every evening. This trough will be enhanced by a tropical wave that is approaching from the east.


A tropical wave is moving across the western portion of the basin with convection. Refer to the section above for details. A diffluent flow aloft along with abundant low-level moisture and the tropical wave support scattered showers and thunderstorms over Cuba, the Yucatan Peninsula and adjacent waters to 16N. The monsoon trough extends along 10N enhancing convection across Panama, Costa Rica and adjacent waters. To the east, a surface trough is in the east Caribbean extending from 18N66W to 11N66W. Elsewhere, a broad high pressure over the Atlantic extends across the basin supporting fair weather and maintaining a pressure gradient to support fresh to near gale-force winds in the south-central Caribbean. These winds are forecast to prevail over the next two days.


Scattered showers and thunderstorms have developed over the western portion of the island. Model guidance indicate that this activity will persist through tonight and then fair weather will set in through at the next 24 hours.


Three tropical waves are moving across the basin. Refer to the section above for details. An upper-level low centered over adjacent waters of Georgia and S Carolina continue to support scattered showers and thunderstorms just north of the Bahamas and west of 76W. A surface trough extends from 27N69W to 23N70W with isolated showers along it. The remainder of the basin is under the influence of a broad surface ridge anchored by a 1022 mb high centered near 28N59W. No major changes expected the two to three days.

For additional information please visit http://www.hurricanes.gov/marine