[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060552
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1252 AM EST Fri Mar 6 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 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: Strong winds will continue across
the south central Caribbean through Sun night, pulsing to minimal
gale force near the coast of Colombia early this morning. These
winds are occurring due to a locally tight pressure gradient with
high pressure ridging NE of the area, and low pressure over
northern Colombia. Seas will build to 8-11 ft with these winds.
Please refer to the Atlantic High Seas Forecast under the AWIPS
header MIAHSFAT2 and under the WMO header FZNT02 KNHC or at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near
11N15W to 05N17W to 01N25W. The intertropical convergence zone
continues from 01N25W to 04S37W. Scattered moderate convection is
observed from 03S to 01S between 22W and 24W, and from 01N to 03N
between 24N and 26N.

GULF OF MEXICO...

A cold front is analyzed at 00 UTC from a small low pressure near
Jacksonville, Florida, to another small low pressure area near
Apalachicola, Florida, then southward across the eastern Gulf to
Merida Mexico on the northwest part of the Yucatan peninsula. A
few showers were active over the northeast Gulf ahead of the
front during the evening, but have since moved onshore. No other
significant shower or thunderstorm activity is observed across the
Gulf. A reinforcing cold front over Texas is approaching the
northwest Gulf this morning. The second front is noted over
eastern Texas and central Louisiana, approaching the northwest
Gulf. Seas are building behind the first front, with buy data
showing generally 5 to 7 ft. Buoy and scatterometer satellite data
indicate fresh northerly flow behind the first front.

The first front will continue SE and reach from near Sarasota,
Florida to the NE of the Yucatan peninsula later this morning,
then exit the basin later today. Fresh to strong winds and
building seas are expected through early Sat in association with
the front, and the reinforcing front moving through the northern
part of the basin. Strong NE to E winds will prevail through the
Straits of Florida and SE Gulf through Mon night before conditions
gradually improve basin wide.

CARIBBEAN SEA...

Please read the Special Features section for more details about
the Gale Warning in effect in the S-central Caribbean Sea.

A 1020 mb surface high pressure area was analyzed over central
Cuba at 00 UTC. Farther south, a 1005 mb low pressure was anchored
over north central Cuba. A pair of recent scatterometer satellite
passes indicated a large area of strong trade winds between these
pressure fields over the south central Caribbean, reaching near
gale force off the higher terrain along the coast of northeast
Colombia. Seas are generally 8 to 9 ft in the area of strong trade
winds over the south central Caribbean, reaching as high as 11 ft
off Colombia in the area of near gale force winds. Elsewhere
moderate to fresh trade winds prevail with 3 to 5 ft seas. No
significant showers or thunderstorms are evident on satellite
imagery or regional radar, other than a few passing trade wind
showers in the eastern Caribbean.

The strong winds will continue across the south-central Caribbean
into early next week, pulsing to gale off Colombia. A cold front
across the Gulf of Mexico will enter the NW Caribbean this
afternoon, reach from eastern Cuba to the central Gulf of Honduras
Sat afternoon, from central Hispaniola to near the Honduras-
Nicaragua border Sun morning, then stall from the Virgin Islands
into central Caribbean Mon. Strong to near gale force NE winds and
large seas will develop behind the front across the Caribbean and
Atlc Passages through late Mon.

ATLANTIC OCEAN...

A cold front is moving off the northeast coast of Florida
currently. A line of thunderstorms is active well off the coast
of northeast Florida, where the cold front has intersected with
the Gulf Stream. Recent scatterometer satellite data shows fresh
to strong SW winds ahead of the front. The axis of the subtropical
ridge has shifted slightly southward to roughly 25N, through the
central Bahamas, ahead of the advancing frontal boundary.

The front will reach from 31N69W to western Cuba by this evening,
from 25N65W to the Windward Passage Sat evening, then stall and
weaken over near the Virgin Islands Sun night through Mon. Strong
to near gale force winds are expected across the waters north of
29N ahead of the front through tonight night, with strong winds
and large seas behind the front through Mon.

Farther east, a mid to upper low is centered near 28N38W. This is
supporting a nearly stationary surface low near 25N45W. A few
showers and thunderstorms remain active within 90 nm of the
surface low, supported by the cold-core low aloft. Earlier
scatterometer satellite data showed fresh to strong winds north of
the surface low, between it and high pressure to the northeast. A
frontal boundary along 28N from roughly the Canary Islands to the
surface low is dissipating. An earlier scatterometer pass showed
winds parallel to the boundary, and the front is under
southwesterly flow from the lower to upper levels of the
atmosphere. The presence of the surface low has disrupted the
subtropical ridge over the area, and is maintaining only moderate
trade wind flow farther south in the deep tropical Atlantic west
of the Cabo Verde Islands. The divergence aloft on the southeast
side of the upper trough along with the trade wind convergence in
the lower levels of the atmosphere is supporting a couple of
clusters of showers and thunderstorms near the ITCZ. Even though
trade winds are suppressed, recent altimeter satellite data shows
8 to 11 ft seas, mainly north of 15N and east of 50W, likely due
to northerly swell.

The surface low is forecast to weaken through today as the upper
support diminishes and lifts to the northeast. This will allow
trade wind flow to increase slightly by Sat over the tropical
Atlantic waters as the ridge builds to the north.

$$
Christensen
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