Tropical Weather Discussion
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AXNT20 KNHC 210007

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
807 PM EDT Sat May 20 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 1800 UTC surface analysis and satellite imagery through
2315 UTC.


A tropical wave is in the eastern Atlantic with axis extending
from 12N26W to 03N28W, moving west at 10 kt. Based on current SAL
analysis from UW-CIMSS, african dust is N and W of the wave.
Isolated moderate convection is confined to the ITCZ.

A tropical wave is over the Windward Islands with axis extending
from 15N59W to Guyana near 07N60W, moving west at 10-15 kt. A few
showers are noted near the wave axis south of 11N, including
parts of northern Guyana. The TPW animation shows a surge of
moisture along the wave axis.

A tropical wave is over the Yucatan Peninsula extending from
21N89W to 12N89W. The wave is moving west at 15 kt. This wave
remains embedded within an area of deep layered moisture,
especially N of 15N, as depicted in the TPW animation.


The Monsoon Trough enters the tropical Atlantic near 09N13W and
continues to 07N19W. The ITCZ extends from 07N19W to 07N26W, then
resumes west of a tropical wave at 06N29W to the coast of Brazil near
02N50W. Isolated moderate convection is noted from 06N-09N
between 16W-25W.



A 1022 mb High is located over the W Atlantic near 32N63W. A ridge
axis extends W to E Texas. 10-15 kt SE surface winds are over the
Gulf of Mexico. A cold front is inland over S Texas with
convection, moving E. Elsewhere, scattered showers and isolated
thunderstorms are over the NE Gulf N of 27N, and inland over NW
Florida. In the upper levels, an upper level trough is over Texas.
Upper level diffluence is over the N Gulf N of 27N enhancing
convection over the N Gulf States. Expect the cold front to be
over the Texas coast in 24 hours with convection.


A tropical wave is over the Windward Islands and a second
tropical wave is over the Yucatan Peninsula. Please see above.
A High located near Bermuda combined with a Low over N Colombia
is supporting 15-25 kt tradewinds over the Caribbean Sea.
Strongest winds are over the central Caribbean. Scattered moderate
convection is over the SW Caribbean and Central America S of 16N.
Scattered showers are over the N Caribbean N of 16N. Expect little
change over the next 24 hours.


Daytime heating, local sea breezes and mountain upslope lifting
will combine with available moisture to produce some cloudiness
with scattered showers and isolated thunderstorms mainly during
the afternoon and early evening hours.


High pressure dominates most of the Atlantic Ocean. A 1022 mb
high is located near Bermuda while another 1023 mb high is center
over the E Atlantic near 29N39W. A surface trough extends N of the
Leeward Islands from 24N59W to 18N63W. A recent scatterometer
pass shows moderate to fresh SE winds on the east side of the
trough axis. This feature is ahead of an upper-level trough that
extends from 31N57W to the Turks and Caicos Islands. Abundant mid-
upper level moisture ahead of this trough is forecast to drift

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