000 AXNT20 KNHC 041057 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 657 AM EDT Sat Apr 4 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 0600 UTC surface analysis and satellite imagery through 1045 UTC. ...SPECIAL FEATURES.... Atlantic Gale Warning: Gale conditions are forecast for a portion of the northern waters of the central this afternoon and continue until early Sunday. A cold front, associated with a deep and complex low pressure system north of the area, will bring gale force west to northwest winds to the waters north of about 30N and between 61W and 66W along with wave heights in the range of 15-18 ft. These conditions will shift northeast of the forecast waters during Sun morning as the cold front pushes farther eastward across the central Atlantic and while the broad gale- force wind field tied to the complex low pressure system lifts northeast of the area. Please read the latest High Seas Forecast product, under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC, or at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Sierra Leone near 08N14W to 04N20W, where overnight scatterometer data indicated that it transitions to the ITCZ axis and continues to 03N30W to the equator at 38W and to the coast of Brazil near 01S47W. Scattered moderate to strong convection is within 120 nm north of the ITCZ axis between 24W-28W, and within 60 nm of the ITCZ axis between 20W-24W and also between 28W-33W. Scattered moderate to isolated strong convection is within 30 nm of the ITCZ axis between 33W-38W and between 18W-20W. Scattered moderate convection is just north of the ITCZ axis within 30 nm of a line from 01N40W to 01N48W. GULF OF MEXICO... The earlier cold front over eastern Texas has become stationary as of 04/0900 UTC from Houston to vicinity Corpus Christi and southwestward from there to just eats of Laredo. Both satellite imagery and regional NWS radar displays reveal scattered to strong thunderstorms inland over southern Texas and extending out to the far western Gulf waters from 26N-28N. This activity is being supported by pretty decent upper-level jet dynamics. Patches of rain with scattered showers are over some sections of the central and NW Gulf areas. This is due to abundant moisture seen on TPW imagery and upper-level diffluence in the area located ahead of an upper-level trough over the central U.S. Weak high pressure over the eastern Gulf is maintaining gentle winds across much of the eastern Gulf. Moderate easterly winds are noted over the western Gulf, except for fresh to strong east to southeast winds over the south-central Gulf due to the gradient associated with the thermal trough emerging off the west coast of the Yucatan Peninsula. Smoke from agricultural fires in southern Mexico may be causing minor limitations to visibility over the SW Gulf. The weak high pressure over the eastern Gulf will shift eastward through Sat night in response to low pressure and the aforementioned stationary front, which will begin to move eastward as a cold front later this morning. The front is expected to reach the Texas coast Sat, then become stationary before it lifts back north as a warm front Sun. This front will trigger showers and thunderstorms over the far NW Gulf Fri night through Sat night. High pressure from off the Carolina coast will slide southward early next week setting up an east to west ridge across the area. This will allow for generally light to moderate east to southeast winds over the basin through Wed night. Fresh to strong winds will pulse each evening north and west of the Yucatan Peninsula through the period as thermal troughs emerge off the Peninsula to across SW Gulf. CARIBBEAN SEA... A rather weak pressure gradient is noted across the basin under very dry aloft as indicated by the strong subsidence signal in water vapor imagery. These means there is considerable lack moisture in the Caribbean, with the exception of the SE part, including the coast of South America, where scattered to broken low clouds with possible isolated showers are present. The TPW satellite animation detects this moisture. Overnight scatterometer data shows moderate to fresh east winds south of 14N and between 61W-78W, with the exception being a small area of strong northeast to east winds along and near the coast of Colombia. The scatterometer shows gentle to moderate east winds elsewhere, except for a pocket of fresh winds over the eastern part of the Gulf of Honduras. Winds over the basin will gradually increase through the middle of next week as high pressure rebuilds over the western Atlantic. Fresh to strong winds will pulse each night during the forecast period beginning Sat night over the Gulf of Honduras and especially along the coast of Colombia. Fresh to strong northeast winds are expected through the Windward Passage Mon night and again Tue night. ATLANTIC OCEAN... Gale force winds are forecast for a section of the northern- central waters beginning this afternoon. See Special Features section above for details on this event. A cold front, associated with a complex low pressure system located well north of the area off New England and the mid- Atlantic region, extends from near 32N60W to 25N70W. This is the cold front that will be followed by gale force winds beginning this afternoon as described above under Special Features. Meanwhile, a second, slow-moving cold front, that is also tied to the same complex low pressure system, is analyzed from 32N41W to 26N55W and to just inland the northern part of Hispaniola. Overnight scatterometer data nicely depicted an extensive area of strong west to northwest winds north of 29N and west of the first cold front to 72W, while fresh west to northwest winds are elsewhere north of 27N between the cold front and 74W. Strong west winds are about 240 nm east of the first cold front. A satellite altimeter pass captured wave heights to 13 ft near 29N30N, and another pass captures wave heights to 12 ft north of 27N and between 56W and 60W. Latest satellite imagery shows broken to overcast low and mid- level clouds along and within 150 nm southeast of the slow moving cold front. Patches of rain along with scattered showers are possible underneath these clouds, mainly north of 28N where upper- level jet stream dynamics could assist in keeping this activity active. Fresh to strong southwest are within 180 nm southeast of this slow-moving cold front. Long-period north swell is propagating through much of the central and western Atlantic waters, namely east and northeast of the Bahamas. A weak 1017 mb high is centered at 23N41W. The related pressure gradient is allowing for generally light to moderate winds in the 14N-24N latitude band across the entire Atlantic and Caribbean. In the far eastern Atlantic, a weak cold front extends from 32N14W to across the Canary Islands and to near 24N18W. Lack of atmospheric forcing due to dry sinking air aloft as seen in water vapor imagery, and along with dust in this area of the Atlantic is suppressing shower and thunderstorm activity with this front. The cold front that extends from 32N60W to 25N70W will quickly reach from near 32N57W to 23N69W by late tonight and from near 32N50W to 23N66W by late Sun night. The slow-moving cold front will move to east of the Leeward Islands near 18N62W by Mon morning. Gale conditions are expected near 30N64W from this afternoon till early Sun as a deep low pressure system centered southeast of New England drops southeastward passing just east of Bermuda Sun morning. North swell generated by the low will produce very large seas across the waters east and northeast of the Bahamas through the weekend. Seas will gradually subside through early next week as the swell decays. High pressure will shift southward over the north-central waters Mon night into Tue. It will then shift southeastward through Wed night as a cold front moves across the NW waters. The front will be preceded by increasing south to southwest winds and accompanied by scattered showers and thunderstorms. $$ Aguirre