AXNT20 KNHC 181154

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
647 AM EST Sat Nov 18 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 0600 UTC surface analysis and satellite imagery through 1015 UTC.


A cold front will reach the NW Gulf of Mexico tonight, and will move across the remainder of the Gulf through Monday. Strong high pressure building behind the front will produce gale force winds over a portion of the SW Gulf S of 25N to the west of the cold front beginning 1200 UTC Sunday and persisting until Sunday night. See the latest high seas forecast under AWIPS/WMO headers HSFAT2/FZNT02 for more details.


The monsoon trough extends from the African coast near 09N13W to 08N20W. The Intertropical Convergence Zone axis extends from 08N20W to 06N24W to 08N36W, then resumes west of a surface trough near 07N40W to the South American coast near 07N58W. Isolated moderate convection is from 04N-11N between 12W-24W. Scattered moderate convection is from 08N-11N between 38W-45W.



A 1021 mb high is centered over North Carolina near 35N78W. A surface ridge axis extends SW from the high to the central Gulf of. A stationary front continues to Mexico near 25N90W. 10-15 kt surface winds are over the base of the ridge axis. Radar imagery shows isolated showers over the Straits of Florida between 81W- 83W. Fair weather is over the remainder of the Gulf of Mexico. In the upper levels, a large upper level high is centered over central Mexico near 23N102W producing northerly upper level flow and strong subsidence over the entire Gulf of Mexico. The next cold front is expected to emerge off the Texas and Louisiana coasts Saturday evening with showers. Gale force winds are expected Sunday behind the front over a portion of the SW Gulf. See the special features section for more details. Elsewhere, 25- 30 kt N-NE winds will follow in the wake of the front as it sweeps southeastward.


A surface trough extends from Hispaniola at 20N70W to N Colombia at 07N75W. Two 1008 mb lows are embedded on the trough axis at 18N72W and 11N74W. Scattered showers and clusters of scattered moderate convection are within 360 nm E of the trough axis, to include Puerto Rico. In the upper levels, an upper level trough is over the NW Caribbean with axis from central Cuba near 22N80W to the Gulf of Honduras near 16N89W. Upper level diffluence E of the trough is enhancing the showers and convection over the central Caribbean Sea. Expect the area of convection to drift E and persist for the next 48 hours.


Scattered showers are over the island, and will continue through the weekend. Expect convection to be heaviest over E Hispaniola in the afternoon and evening hours during maximum heating. Localized flooding is also possible during this time.


A 1007 mb low is centered over the central Atlantic near 26N57W. A surface trough extends SW from the low to Hispaniola near 20N70W. Scattered moderate to isolated strong convection is N of the Leeward Islands from 19N-23N between 59W-67W. Scattered showers are elsewhere within 120 nm of the trough. A quasi- stationary front enters the central Atlantic near 31N38W and extends to 27N50W to the central Atlantic low near 26N57W. Scattered showers are within 120 nm of the frontal system. A 1019 mb high is centered over the E Atlantic near 27N28W. Of note in the upper levels, a large upper level trough is over the W Atlantic enhancing the central Atlantic with upper level diffluence. Another upper level trough is over Morocco.

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

$$ Formosa