[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202348
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
748 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...TROPICAL WAVES...

A tropical wave is in the E Atlc with axis extending from 06N-18N
along 26W, moving W at 10-15 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. This is inhibiting convection
at this time.

A tropical wave is in the central Atlantic with axis extending
from 06N-20N along 41W, moving W at 15 kt. The wave is moving
across an extensive area of Saharan air, which is hindering
convection at the time.

A low amplitude tropical wave is moving across Venezuela with
axis extending from 00N-10N along 64W, moving W at 15-20 kt.
Scattered moderate convection is observed along the wave's axis.
This wave is forecast to move to EPAC waters on Mon.

A tropical wave is in the west-central Caribbean with axis along
79W, moving W at 15-20 kt. Scattered showers are noted along the
wave's axis in the vicinity of the monsoon trough mainly south of
12N.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of W Africa near
14N17W and continues to 07N38W. The ITCZ begins near 07N42W and
continues to South America near 07N58W. No significant convection
is observed along these boundaries at this time.

...DISCUSSION...

GULF OF MEXICO...

The feature of interest in the Gulf continue to be a surface
trough that extends from northern Florida near 30N83W to 28N89W.
This feature is being supported by a mid-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 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 west-central portion of the 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 supports scattered
showers and tstms. For more information about the wave, see the
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...

Mid 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 1035 mb
high near 40N39W. 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

$$

ERA/NR
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