[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011102
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
602 AM EST Thu Mar 1 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...SPECIAL FEATURES...

A 978 mb low pressure center is near 39N11W off Portugal. A cold
front is connected with the low center, and it passes through
Morocco and Western Sahara. Scatterometer passes over the past
several hours continued to show gale force winds from 29N to 32N
east of 23W, and Meteo France has forecast gale warnings for
zones Irving, Madeira, and Agadir for the next 48 hours.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Liberia near 06N10W to 01N12W. The ITCZ continues from 01N12W,
crossing the Equator along 13W, to 04S24W, to 03S38W.
Precipitation: widely scattered moderate to isolated strong from
03N southward from 09W eastward. isolated moderate to locally
strong rainshowers from 13N southward between 30W and 50W, and
elsewhere from 10N southward from 60W eastward.

...DISCUSSION...

GULF OF MEXICO...

Weak ridging extending from Tampa Florida to Tampico Mexico is
supporting light to gentle winds over the eastern Gulf with 2 to
4 ft seas, and moderate to fresh southerly flow over the western
Gulf with 4 to 6 ft seas. The moist southerly flow over the
western Gulf is maintaining dewpoints into the lower 70s over the
northwest Gulf, where platforms are indicated 4 to 5 nm in fog.
The fresh southerly flow will diminish later this morning and the
fog will lift as the ridge shifts eastward ahead of a cold front
moving across the southern plains.

The front will move into the northwest Gulf early Thu. Strong
northerly winds will follow the front along the coast of Mexico
until Fri evening. The front will stall from western Cuba to near
Veracruz Mexico Fri night, then dissipate Sat. A ridge will
build across the northern Gulf Sun and Mon.

CARIBBEAN SEA...

Buoy and scatterometer satellite data indicate moderate trade
winds across the region currently. This is due to weakening high
pressure north of the area, although the gradient is tight enough
to support pulses of fresh to strong winds off Colombia this
morning, and support fresh NE winds in the lee of Hispaniola.
Seas are generally 3 to 5 ft, but range 5 to 7 ft in areas of
stronger winds. Divergence aloft related to an upper level
trough reaching from the Mona Passage to Panama is supporting a
few trade wind showers from the Leeward Islands to the ABC
Islands. Subsidence along the trough axis and to the west of the
trough is inhibiting showers elsewhere.

Looking ahead, high pressure north of the area will support
moderate to locally fresh trade winds across the basin, with
strong winds pulsing at night off Colombia through late week.
Large NE swell will impact the tropical Atlantic waters through
Sat, with an even more significant N swell event penetrating the
NE Caribbean Sun night.

ATLANTIC OCEAN...

East of 60W, light to gentle winds persist across the region
associated with weak ridging along 29N. Farther south, a
dissipating trough persists along 24N through the central Bahamas.
No significant shower or thunderstorm activity is noted. Recent
buoy observations and a recent altimeter satellite pass indicated
7 to 9 ft seas north of 22N and east of the Bahamas, related to
northeast swell. Looking ahead, the weak ridging along 29N will
shift east ahead of a cold front moving off the NE Florida coast
late today. The front will reach from Bermuda to SE Florida Fri
afternoon, just ahead of a reinforcing front which will generate
strong to gale force winds north of 27N east of 75W as deep low
pressure moves off the Virginia coast. The fronts will merge Sat
and stall from 22N65W to the Windward Passage by Sun before
dissipating Mon. A significant swell event and likely the largest
of this winter season will accompany this system, affecting all
waters E of Florida and the Bahamas by the end of this week.

West of 60W, a cold front reaches from 31N35W to 25N60W. Fresh
northerly winds are noted north of the front. But the main weather
impact continues to be large northerly swell dominating the entire
region east of 60W. Various recent altimeter satellite passes
indicate seas as high as 15 ft between 35W and 60W, and in excess
of 20 ft east of 35W, mainly in the area of gales mentioned in the
Special Features section. The swell will subside to 8 ft or less
through Sun, just ahead of another significant swell event
originating out of the north central Atlantic.

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

$$
Christensen
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