[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011725
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
705 AM EST Thu Mar 1 2018

Corrected Special Features section

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
1145 UTC.

...SPECIAL FEATURES...Corrected

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. The OUTLOOK, for the 24 hours that follow the
forecast that is valid until 02/1200 UTC, consists of: the
persistence of a westerly near gale or gale in : IRVING,
MADEIRA, and AGADIR.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends through the coastal sections of
Liberia near 06N10W to 01N12W. The ITCZ continues from 01N12W,
crossing the Equator along 13W, to 04S24W, to 03S35W. Scattered
moderate isolated strong convection is within 90 nm S of the ITCZ
axis between 27W-35W, and also from 06S-03S. Scattered moderate
convection is within 60 nm S of the ITCZ axis between 19W-22W.

...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. Moist southerly flow over the western
Gulf has assisted in the development of fog over some locations
there, where platforms are indicating visibilities of 3-5 nm. 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 cold front, presently over eastern Texas, will move into the
NW Gulf this morning. 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 maintaining fairly dry conditions elsewhere.

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 Fri. Large NE swell will impact the
tropical Atlantic waters through Sat, with an even more
significant N swell event will propagate through NE Caribbean
Sun night.

ATLANTIC OCEAN...

East of 60W, light to gentle winds persist across the region
associated with weak ridging along 29N. 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. The weak
ridge along 29N will shift eastward ahead of a cold front that
will move off the NE Florida coast late this afternoon or evening.
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 32N34W to 25N52W and
to 24N68W, where it transitions to a trough to over the central
Bahamas.  Fresh northerly winds are noted north of the front. But
the main weather impact continues to be large northerly swell
dominating the entire region to the east of 60W. Earlier altimeter
data indicated 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/Aguirre
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