AXNT20 KNHC 272300

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2300 UTC Wed May 27 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 1800 UTC surface analysis and satellite imagery through 2230 UTC.


Tropical Depression Bertha is centered near 34.4N 80.3W at 27/2100 UTC or 50 nm ENE of Columbia South Carolina moving NNW at 13 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. A turn toward the north at a faster forward speed is expected tonight, followed by a turn toward the north-northeast on Thursday. On the forecast track, Bertha will move across northern South Carolina this evening and into central North Carolina and southwestern Virginia later tonight.

Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT2.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for more details.

Central America Heavy Rainfall: A Central American Gyre will develop in the eastern North Pacific by the end of the week. The gyre will move northward toward Central America and southern Mexico this weekend. This will advect abundant moisture into portions of Central America by the end of the week, through the weekend, and into next week. There is the potential for heavy rainfall over portions of Central America, especially from northern Costa Rica northward into southern Mexico. This will bring the potential for life-threatening flash floods and mudslides for the areas that receive the heaviest rainfall. Please refer to products issued by your local weather service for more information.


A tropical wave is along 63W south of 19N, moving W at 15-20 kt. No significant convection is associated with this wave.


The monsoon trough extends from the coast of Guinea near 11N15W to 07N21W. The ITCZ extends from 07N21W to 01N49W. Scattered moderate convection is noted within 120 nm of the ITCZ between 25W and 31W.


A mid- to upper-level trough extends from the U.S. Southern Plains to the lower Mississippi Valley, while at the surface a weakening cold front extends from SE Louisiana into the north- central Gulf. Earlier scatterometer data depicted light to gentle winds across the Gulf, with seas generally 3 ft or less based on recent buoy observations. No significant convection is noted over the Gulf this evening, although a line of strong thunderstorms is crossing the Houston metro area and approaching the Texas coastal waters. The latest smoke analysis indicates light smoke from agricultural fires in Mexico lingers over the SW Gulf.

A weak trough over the NE Gulf will lift north and dissipate by tonight. Weak low pressure over Louisiana and an associated stationary front extending SW to just S of Tampico, Mexico will also dissipate by Thu. A cold front may move off the TX coast Thu night, but stall and weaken in the NW Gulf Fri. Areas of smoke from fires in southern Mexico may at times reduce visibility in the SW Gulf.


Some scattered moderate convection lingers over the far SW Caribbean this evening, in association with an active eastern Pacific monsoon trough. Diurnal convection is noted over the Greater Antilles and near the Virgin Islands. Several earlier scatterometer passes showed fresh trades in the south-central Caribbean, with gentle to moderate trades elsewhere across the basin. Earlier altimeter data and buoy observations indicate wave heights peak around 7-8 ft within the fresh trades off the coast of Colombia and Venezuela.

Fresh trades will persist in the south-central Caribbean through the end of the week. A tropical wave is moving through the Windward Islands this afternoon, and will cross the eastern Caribbean before reaching the central Caribbean Fri. Increasing showers and thunderstorms are expected over the southwest Caribbean and adjacent portions of South and Central America this weekend.


Tropical Depression Bertha has moved well inland over the Carolinas, and associated winds off the Florida coast are diminishing this evening. A line of thunderstorms that moved off the Florida coast earlier today is now passing north of the NW Bahamas. Elsewhere, scattered moderate to strong convection is occurring east of a surface trough that extends from 23N56W to 19N60W, with support from a vigorous mid-level low noted in water vapor imagery. Farther east, a dissipating cold front is analyzed from 31N30W to 28N34W. Moderate trades prevail S of 20N over the central Atlantic, while moderate to fresh E winds are noted in earlier scatterometer data N of 25N in the vicinity of another surface trough along 50W.

Some fresh southerly winds in association with Bertha north of 29N offshore Florida will diminish by Thu. For the remainder of the week, weak high pressure will build in from the N and E and dominate most area. A trough of low pressure may impact areas north and east of Puerto Rico this weekend.

$$ B Reinhart