000 AXNT20 KNHC 150506 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 106 AM EDT Tue May 15 2018 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 0445 UTC. ...SPECIAL FEATURE... Broad mid to upper-level low pressure is centered over the NE Gulf of Mexico near 27N85W. The surface reflection of this system manifests as weak surface low pres centered over the eastern Gulf near 26N85W. A surface trough extends SW from N of Tampa near 28.5N82.5W through the low to 23N86W. Areal coverage and intensity of the convection associated with this system have both decreased during the past 6 hours. Scattered moderate and isolated strong convection is confined to areas along the Florida E cast from 25N to 30N between 78W and 81W and over the Gulf of Mexico S of the Florida Panhandle from 28N to 30N between 84W and 87W. Although this system still has the potential to acquire some subtropical or tropical characteristics as it drifts N or NNW across the eastern Gulf of Mexico during the next few days, the low is not exhibiting signs of increased organization. Regardless of subtropical or tropical cyclone formation, this system will produce locally heavy rainfall and possible flash flooding across portions of Florida and the southeastern United States during the next few days. ...MONSOON TROUGH/ITCZ... The monsoon trough heads SW from coastal sections of Sierra Leone near 08N13W to 04N18W. The ITCZ continues from 04N18W to 02N31W to 03N37W to the Mouth of the Amazon on the coast of Brazil near 00N51W. Scattered moderate and isolated strong convection is observed from 07N to 15N between 11W and 18W and from 02N to 05N between 43W and 52W. ...DISCUSSION GULF OF MEXICO... A broad low pressure system will linger over the eastern Gulf and produce heavy rainfall. This system will be the main weather producer over the eastern Gulf during the next few days. Satellite-derived winds indicate moderate to fresh winds in the vicinity of the low over the eastern Gulf. Please see the special features section for more details on this system. High pressure measuring 1014 mb is centered over the NW Gulf near 29N93W. The high ridges SSW over the Bay of Campeche. Convergent winds on the E side of an upper-level ridge there are inhibiting convection. A surface trough extending over the Yucatan Peninsula and Guatemala from 21N87W to 16N90W will move offshore tonight over the Bay of Campeche and bring fresh winds with it but no significant convection. This pattern will continue to repeat itself over the SW Gulf through this week. Otherwise, relatively quiet weather is expected to continue over the western Gulf over the next few days. CARIBBEAN SEA... Convergent upper-level winds associated with troughing over the basin near 80W and over the Antilles is restricting convection. This relatively dry weather pattern is expected to continue for the next couple of days. High pressure over the Atlantic is helping to produce moderate trade winds over the NW Caribbean, and mainly fresh trade winds over the remainder of the basin. Winds over the southern Caribbean near the coast of Colombia will pulse to strong at night during the next few nights, expanding to include the south central coast of Hispaniola by Thu. ATLANTIC OCEAN... Deep layer low pressure centered over the eastern Gulf of Mexico is supporting scattered moderate and isolated strong convection along the Florida E coast. See the special feature section for more details. A large high pressure system centered near the Azores ridges WSW to the S Carolina coast. The pressure gradient between the high and lower pressure associated with the Gulf of Mexico trough/low supports fresh SE winds over the central and NW Bahamas and nearby waters. Winds are expected to pulse to strong off the coast of N Florida from 27N to 30N between 78W and 80W today, then decrease tonight. Otherwise, winds will be moderate over the tropical Atlantic N of the ITCZ between 30W and 45W and moderate to fresh over the tropical Atlantic between the Windward Islands and 45W during the next couple of days. Winds N of Hispaniola will pulse from fresh to strong from afternoon to late evening each day through Sat. The area of strong winds N of Hispaniola will expand northward to as far as 23N by Sat as the high pressure ridge over the western Atlantic gradually strengthens and low pressure over northern South America deepens slightly. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy