[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 PM EDT Fri Jul 20 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
1745 UTC.

...TROPICAL WAVES...

A tropical wave is in the E Atlc with axis extending from 5N-17N
along 24W, moving W at 5-10 kt. Saharan dry air and dust continue
to engulf and move into the wave environment as shown by CIRA LPW
and GOES-16 RGBs imagery. Strong deep layer wind shear is also
affecting the wave, which is hindering convection at the time.

A tropical wave is in the central Atlantic with axis extending
from 04N-19N along 39W, moving W at 15 kt. The wave is moving
across an extensive Saharan Air Layer Outbreak, which dry air and
dust hinder convection at the time.

A low amplitude tropical wave is moving across Venezuela with
axis extending from 0N-10N along 63W, moving W at 15-20 kt. No
deep convection is associated with this wave at this time. This
wave is forecast to move to EPAC waters on Mon.

A tropical wave is in the central Caribbean with axis along 78W,
moving W at 20 kt. CIRA LPW imagery show abundant shallow moisture
associated with it, however a thin layer of Saharan dry air and
dust and strong deep layer wind shear in this region of the basin
inhibit convection at the time.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of W Africa near
15N17W and continues along 08N25W to 07N36W. The ITCZ begins near
07N40W and continues to South America near 07N58W. Scattered
showers are S of the monsoon trough from 05N-09N E of 24W.

...DISCUSSION...

GULF OF MEXICO...

The feature of interest in the Gulf continue to be a surface
trough that extends from northern Florida near 30N82W to the Big
Bend to 28N86W to the north-central basin near 28N90W. This
feature is being supported by a middle-level trough over the
eastern CONUS, which also supports a frontal system N of the area.
Abundant deep layer moisture in the NE Gulf along with upper level
diffluent flow continue to support scattered heavy showers and
tstms N of 26N E of 90W, including inland central and northern
Florida. Latest scatterometer data show strong gusty winds in the
vicinity of the trough associated with the convection. Otherwise,
the remainder Gulf is under the influence of the Azores high,
which southwestern periphery extends across the SE basin. This is
providing light to moderate variable winds elsewhere. The trough
is forecast to lift NE of the area by early Sat and surface
ridging will prevail thereafter through early Mon. Otherwise, a
surface trough will move off the Yucatan Peninsula into the Bay of
Campeche each evening, accompanied by fresh nocturnal winds.

CARIBBEAN SEA...

The Caribbean is pretty quiet as strong deep layer wind shear and
very dry air moves across the basin. A tropical wave moves across
the central basin, however lacks convection due to the
aforementioned conditions. The only region of convection is within
150 nm off the coast of Costa Rica and northern Panama where the
EPAC monsoon flow support scattered heavy showers and tstms. For
more information about the wave, see section above. Otherwise, the
southwestern periphery of the Azores high continue to tighten the
pressure gradient in the south-central basin, thus supporting
fresh winds between 65W and 83W. Strong to near-gale winds are
forecast at night along the Colombia coast and adjacent waters. No
major changes expected through early next week.

ATLANTIC OCEAN...

Middle to upper level diffluent flow between a ridge in the SW N
Atlc and a trough along the E CONUS continue to support scattered
showers and tstms N of 25N W of 70W. The remainder basin is under
the influence of the Azores high, which is anchored by a 1034 mb
high near 41N36W. Fair weather is elsewhere, however hazy
conditions are expected S of 26N as an extensive Saharan Air Layer
Outbreak moves across the Atlc tropical waters.

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

$$
Ramos
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