Tropical Weather Discussion
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AXNT20 KNHC 211727

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
127 PM EDT Sat Apr 21 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.


The monsoon trough passes through the coast of Africa near 06N10W
and extends to 02N18W. The ITCZ continues from 02N18W to 00N43W to
07N58W. Scattered moderate to strong convection is noted along
and south of the monsoon trough mainly east of 12W. Scattered
moderate convection prevails within 75 nm on either side of the



A stationary front extends across the basin from 28N96W to 26N90W
to 27N82W. The front will weaken today, with its remnants lifting
northward this afternoon, ahead of a cold front that is expected
to reach the Texas coast by early on Sunday. This front will be
preceded by a line of scattered showers and thunderstorms. The
cold front will reach from the Mississippi Delta to the Bay of
Campeche on Sunday night, from the Florida Big Bend to the Yucatan
Peninsula on Monday night, and then move slowly southeastward on
Tuesday, and eventually move away from the area by Wednesday


Upper level cyclonic wind flow, with a trough, spans the entire
area. The trough cuts across central Cuba, toward the Gulf of
Uraba of Colombia. Lingering rainshowers cover the area that
extends from Nicaragua near 13N northward to the Bahamas near 24N
between 68W/eastern sections of Hispaniola and 88W in parts of
Central America.

Low level cyclonic wind flow prevails in the SW Caribbean
enhancing scattered moderate convection mainly south of 11N
between 78W-84W.

Atlantic high pressure will maintain fresh to locally strong
trade winds across the south-central Caribbean Sea through early
Sunday. Strong nocturnal trade winds then are expected to resume
on Sunday night along the northern coast of the South America.
Northeast swell, currently across the tropical waters that are to
the east of the Leeward Islands, will subside gradually through
this evening. A weakening cold front will pass across the Yucatan
Basin on Tuesday night, and wash out across the northwestern
Caribbean Sea by mid-week.


A cold front is analyzed from 31N62W to 28N80W. The front becomes
stationary from that point west extending across the Gulf of
Mexico. Scattered showers are noted along the front. A pre-
frontal trough extends from 29N63W to 27N78W with scattered
moderate convection affecting the northern Bahamas. The remainder
of the basin is under the influence of a surface ridge, anchored
by a 1031 mb high located near 35N36W.

The front over the west Atlantic will become stationary by
tonight. Remnants of the front will lift northward on Sunday.
Near-gale force southeast wind flow will develop north of the
Bahamas on Monday, to the east of a surface low that will shift
eastward across the southeastern United States. The surface low
will move northeastward along the Georgia and South Carolina
coasts on Tuesday, and drag a cold front across the northwest
waters during the middle part of next week.

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