[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021805
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT Thu Jul 02 2020

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 over western Africa, with axis near 11W, as
observed on long-term satellite imagery. Latest and current
satellite imagery shows increasing deep convection of the
scattered moderate to strong type from 10N to 14N between 11W
and 15W. It is moving westward near 15 kt. Convection ahead of
it is expected to increase along and offshore the coast of
Africa prior to its axis moving offshore that coast.

A tropical wave with axis along 36W from 04N to 17N is moving
westward near 15 kt. This wave is moving through a surrounding
stable atmospheric environment. Only isolated showers and
thunderstorms are seen within 60 nm of the axis from 04N to 07N.

A tropical wave is crossing the Lesser Antilles with its axis
along 61W from 06N to 19N. It is moving westward near 20 kt.
This wave is surrounded by Saharan air, although not as much as
in recent days, but enough to limit convection from developing
near it. Only isolated showers and thunderstorms are seen south
of 14N between 60W and 62W.

A tropical wave with axis along 71W is moving westward at 20-25
kt. Scattered showers and thunderstorms are north of 17N to over
the eastern section of the Dominican Republic and between 69W
and 71W. Isolated showers and thunderstorms moving quickly
westward are north of 15N between 71W and 75W. This activity
likely to produce gusty winds.

The northern part of the axis of a far western Caribbean
tropical wave is just east of Belize and is moving westward at
10-15 kt. The 700 mb GFS model winds indicate a sharp northeast
to southeast wind shift in the vicinity of this wave. The wave
is situated to the east of a small upper-level low that is
centered over the northern Yucatan Peninsula. Upper-level
divergence east of the low in combination with deep atmospheric
moisture in place is helping to aid in the development of
scattered showers and thunderstorms over most of the
northwestern Caribbean and over waters just offshore Belize.
Similar activity is inland Belize and over the southeast part
of the Yucatan Peninsula.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the W coast of Africa
across Guinear near 11N16W and continues to 09N22W and to
08N27W, where a scatterometer pass from this morning indicated
that it transitions to the ITCZ and continues to just east of
the tropical wave along 36W and resumes just to the west of the
same tropical wave near 37W. It continues to 04N42W and to near
05N51W. Aside from the convection associated with the tropical
waves, scattered moderate to isolated strong convection is
within 120 nm north of the trough between 18W and 22W and within
60 nm north of the trough between 22W and 24W. Scattered
moderate convection is within 180 nm south of the trough between
17W and 21W, within 60 nm south of the trough between 21W and
28W, within 60 nm south of the trough between 20W and 24W and
within 60 nm south of the trough between 25W and 28W.

GULF OF MEXICO...

Broad anticyclonic flow is present over the western part of the
Gulf west of 93W, while an upper-level low is over the northern
Yucatan Peninsula. At the surface, a 1017 mb high pressure
center is located over the NE Gulf near 27N88W. The associated
wind flow around it consists of gentle to moderate return flow
west of 93W and generally light and variable winds east of 93W.
Little change in the present weather pattern is expected through
the weekend. Scattered showers and thunderstorms are noted north
of 28N between 86W and 89W. This activity is associated with an
upper-level shear axis over the north-central Gulf. The activity
is weakening with time. Other scattered showers and
thunderstorms are lifting northward from the northwestern
Caribbean Sea and through the Yucatan Channel to near 24N and
between the western tip of Cuba and 88W. This activity is being
steered northward by the southerly flow aloft that is occurring
east of the aforementioned upper-level low. Isolated showers and
thunderstorms are elsewhere east of 90W. The high pressure that
is in place is forecast to maintain rather benign marine
conditions across the region through Mon.

CARIBBEAN SEA...

Refer to the section above for details on a tropical wave along
71W and another one that is crossing the Lesser Antilles and
into the far eastern Caribbean.

Plenty of atmospheric moisture and instability in place is
allowing for scattered to numerous showers and thunderstorms to
continue to develop over most of the western Caribbean west of
80W and also south of 12N between the coast of Colombia and 80W.
Scattered showers and a few thunderstorms are over the Windward
Passage.

The combination of daytime heating, local sea breezes and
available moisture should contribute to the formation of
scattered showers and thunderstorms over the Greater Antilles by
late this afternoon.

The pressure gradient between the Atlantic high pressure and the
Colombian/Panamanian low is supporting fresh to strong trades
across the south-central Caribbean. These winds are forecast to
change little through the weekend. Elsewhere, gentle to moderate
trades will prevail for the next several days.

ATLANTIC OCEAN...

Refer to the section above for details on a central Atlantic
tropical wave and another one that is expected to move into the
far eastern Atlantic in the short term.

In the upper-levels, an upper trough stretches from an elongated
upper-level low near 28N53W southwestward to near 21N56W and to
the far northeastern Caribbean Sea. An upper-level anticyclone is
noted near 27N68W. At the surface, the 1029 mb Bermuda-Azores
high is centered near 34N40W with a ridge extending
southwestward to the central Bahamas. Moderate to fresh trades
are noted along the southern periphery of the ridge. The high
pressure will continue across the area into early next week. Low
pressure will develop Fri morning east of Jacksonville Florida
and move east across the northern waters through Sun afternoon,
bringing some gusty winds as well as some showers and
thunderstorms.

The Saharan Air Layer from CIMSS shows less African dust, than
observed in previous days, over some of the waters between the W
coast of Africa and the Lesser Antilles.

$$
Aguirre
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