[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270948
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
548 AM EDT Fri Oct 27 2017

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
0945 UTC.

...SPECIAL FEATURES...

A center of low pressure interacting with a stationary front off
the coast of NE Nicaragua and E Honduras is generating numerous
heavy showers and scattered tstms currently affecting these
territories, the Cayman Islands, Jamaica, portions of E Cuba, Haiti
and the Windward Passage. Environmental conditions are expected
to be conducive for some development today and Saturday as the
system moves slowly northward over the northwestern Caribbean Sea.
Regardless of development, this system will continue to produce
locally heavy rainfall over the aforementioned territories during
the next day or two. These rains are forecast to spread northward
across portions of South Florida and the Keys on Saturday, and
over the northwestern Bahamas Saturday night and Sunday. There is
a medium chance for this system to develop into a tropical cyclone
within the next 48 hours. See latest NHC Tropical Weather Outlook
under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more details.

...GALE WARNING...

A strong cold front will enter the NW Gulf of Mexico this afternoon,
then it will extend from the Florida panhandle to the western Bay
of Campeche Saturday. Gale force northerly winds are expected S
of 23N W of the front starting early Sunday morning through Sunday
night. See latest NHC High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for more details.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the coast of Sierra Leone near
07N12W to 06N14W where the Intertropical Convergence Zone axis
then begins and continues along 06N30W to 04N43W. Scattered
moderate convection is from 02N-10N E of 30W.

...DISCUSSION...

GULF OF MEXICO...

A broad surface ridge anchored by a 1020 mb high off the coast of
North Carolina extends SW across most of the basin, thus providing
return flow. Latest scatterometer data show fresh SSE winds in
the NW basin and gentle to moderate return flow elsewhere. The
strongest winds in the NW side of the basin is due to a tighter
pressure gradient between the ridge and building low pressure
associated with the next cold front to come off the coast of Texas
this afternoon. The front will then push across the remainder of
the basin through Sunday night. Fresh to strong N winds will
accompany the passage of the front with near to gale force winds
developing south of Tampico, Mexico and the W Bay of Campeche.

CARIBBEAN SEA...

A cold front in the SW N Atlc extends across the Windward Passage
SW to Cuba adjacent waters near 19N76W where it stalls continuing
SW to a 1007 mb low centered just E of Honduras near 15N83W.
Numerous heavy showers and scattered tstms associated with this
system are currently affecting E Honduras, Nicaragua, the Cayman
Islands, Jamaica, portions of E Cuba, Haiti, the Windward
Passage and W Caribbean waters from 10N-20N between 74W-86W.
There is a medium chance for this system to develop into a
tropical cyclone within the next 48 hours. See special features
for further details. Over the E basin, a middle to upper level
low support a surface trough just E of Puerto Rico from 21N63W to
10N65W. Isolated showers are within 120 nm either side of the
trough axis. Except for fresh to near gale force winds W of the
front and in the vicinity of the low center, gentle to moderate
trades are elsewhere. The stationary front will transition into a
warm front today, lifting towards the coastline of S Cuba before
dissipating.

...HISPANIOLA...

A cold front along the coastline of E Cuba to 19N76W becoming
stationary from that point to 15N83W will drift back along
southern Cuba through tonight. Both the front and an area of low
pressure developing off the coast of E Honduras will continue to
support scattered showers and tstms across the Windward Passage
and isolated showers across the Island through this afternoon.
However, a surface trough currently E of Puerto Rico will approach
the Island by Saturday morning with showers mainly affecting the
Dominican Republic.

ATLANTIC OCEAN...

A cold front over the western Atlantic extends from 30N66W to the
Windward Passage near 20N74W with tail becoming stationary in the
NW Caribbean. Scattered to isolated showers are within 150 nm
east of the front. The northern part of the front will weaken in
the central Atlantic today, while the southern part stalls and
drifts NW through Saturday before starting to dissipate Sunday. A
surface trough over the central and eastern Atlantic extends from
25N32W to 21N40W to 20N48W. Isolated showers are within 210 nm
either side of the boundary. Otherwise, a surface trough is
analyzed in the central Atlantic just W of the ITCZ from 13N43W to
04N45W, which is supporting scattered to isolated showers from
06N-13N between 40W-54W. Rains associated with a broad area of
low pressure in the NW Caribbean are forecast to spread northward
across portions of South Florida and the Keys on Saturday, and
over the northwestern Bahamas Saturday night and Sunday. See
special features for further details.

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

$$
Ramos
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