[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 PM EDT Mon Jul 24 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...TROPICAL WAVES...

A tropical wave came off the W coast of Africa earlier this
morning. Its axis extends from 16N17W to 06N17W and according to
global model guidance is forecast to move at 10 kt within the next
24 hours. The wave is in a region of favorable to neutral vertical
wind shear, and is being engulfed by Saharan dry air and dust.
Abundant moisture confined to the vicinity of the African monsoon
along with middle to upper level diffluence support scattered
heavy showers from 07N to 10N E of 20W.

A tropical wave is in the E Atlc with axis extending from 15N27W
to 02N27W, moving W at 15 kt within the last 24 hours. The wave
is in a region of favorable vertical wind shear, however it
continues to be severely affected by Saharan dry air dust, which
is limiting convection to isolated showers from 03N to 09N
between 23W and 35W.

A tropical wave is in the central Atlc with axis extending from
22N39W to 10N39W, moving W at 10 kt within the last 24 hours. The
wave is in a region of favorable to neutral vertical wind shear,
however it continues being severely affected by intrusion of
Saharan dry air dust to its environment, which is supporting lack
of convection at the time.

A tropical wave is in the central Atlc with axis extending from
17N53W to 06N54W, moving W at 10 kt within the last 24 hours. The
wave is in a region of unfavorable to neutral vertical wind
shear that along with prevailing intrusion of Saharan dry air
dust to its environment support lack of deep convection at the
time. Shallow moisture support isolated showers from 11N to 14N
between 52W and 58W.

...ITCZ/MONSOON TROUGH...

The monsoon trough axis extends from 11N15W and continues along
06N28W to 07N39W. The ITCZ begins near 07N39W and continues to
06N45W to 05N52W. For information about convection see the
tropical waves sections above.

...DISCUSSION...

GULF OF MEXICO...

Weak surface ridging prevails across the Gulf waters with gentle
to light variable winds E of 91W and moderate easterly to
southeasterly flow elsewhere. Instability aloft continues in the
form of middle level diffluence and a broad upper level low
centered NW of the Yucatan Peninsula. In the north-central and NE
Gulf, the remnants of a former surface trough support scattered showers
and isolated tstms N of 27N E of 90W. Similar convection is within
120 nm off the northern Yucatan Peninsula and in the SW basin S
of 24N due in part to the passage of a tropical wave with axis
approximately along 94W. CIRA LPW and water vapor imagery show
very dry air elsewhere, which support fair weather. No major
changes expected during the next two to three days.

CARIBBEAN SEA...

Except for a portion of the NW Caribbean and the SW basin, the
remainder basin is under dry air subsidence and unfavorable
vertical wind shear, which is supporting fair weather at the time.
In the NW Caribbean, instability associated with the passage of a
tropical wave currently moving across EPAC waters and the SW Gulf
of Mexico along with upper level diffluence support scattered
showers and isolated tstms W of 76W. In the SW basin, the eastern
extension of the E Pacific monsoon trough support scattered heavy
showers and tstms S of 11N W of 80W. Otherwise, strong high
pressure over the Atlc extending a ridge along the northern basin
increase the pressure gradient enough to maintain the continuation
of fresh to near gale-force winds in the south-central Caribbean.
These winds are forecast to prevail the next two days.

...HISPANIOLA...

With dry sinking air aloft advecting westward across the island,
only isolated showers and thunderstorms are possible to develop
with daytime heating combining with local island effects today and
again on Tuesday.

ATLANTIC OCEAN...

Upper level divergence between an upper level high centered along
the Georgia coast and the SW periphery of a broad upper level high
centered near 34N54W support scattered heavy showers and tstms in
the SW basin W of 70W. In the tropical Atlc, three waves are in
the central basin while one last one is just off the W African
coast. Refer to the section above for details. The remainder of
the basin is under the influence of a broad surface ridge anchored
by a 1033 mb high centered near the Azores and a 1023 mb high near
28N61W. No major changes expected through next couple of days.

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

$$
Ramos
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