[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191136
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Sep 19 2022

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 31N. 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...

Hurricane Fiona is centered near 18.5N 68.6W at 19/0900 UTC or
inland the eastern Dominican Republic about 10 nm WSW of Punta
Cana moving NW at 7 kt. Estimated minimum central pressure is 977
mb. Maximum sustained wind speed is 80 kt with gusts to 100 kt.
Wave heights of  12 ft or greater extend out 120 nm in N
semicircle, 90 NM in the SE quadrant and 60 nm in SW quadrant.
Peak seas are currently 24 ft in the Mona Passage. Seas are
expected to build to 38 ft by the time Fiona strengthens to a
major hurricane over the Atlantic late Tue. Numerous strong
convection associated with the core of Fiona extends outward to
45 nm E semicircle and 60 nm W semicircle. Satellite imagery
shows that Fiona quickly has become more organized in overall
pattern structure as a clear eye feature became apparent during
the overnight hours. The imagery shows tight and wide banding
features around the eye that consist of numerous moderate to
strong convection within 60 nm of the eye, except for 45 nm in the
NW quadrant. Outer banding features that consist of scattered to
numerous moderate to isolated strong convection are noted
elsewhere within 270 nm of the eye in the NE quadrant and within
240 nm of the eye in the SE quadrant. Some of these bands are
affecting Puerto Rico with catastrophic flooding. Fiona is
forecast to produce an additional 4 to 6 inches of ran with local
maximum of 10 inches over southern Puerto Rico and over the
northern and eastern Dominican Republic. Over northern Puerto
Rico, Fiona is forecast to produce additional 1 to 4 inches with
local maximum of 6 inches. Storm Total over that part of Puerto
Rico is 4 to 12 inches with local maximum of 20 inches. Fiona will
continue on its present motion through tonight, followed by a
turn toward the north-northwest on Tue and the north on Wed. On
the forecast track, the center of Fiona will move over the eastern
portion of the Dominican Republic this morning and emerge over
the southwestern Atlantic this afternoon. The center is forecast
to pass near or to the east of the Turks and Caicos on Tue. Some
strengthening is expected during the next few days after the Fiona
emerges over the southwestern Atlantic, and Fiona is forecast to
become a major hurricane by Wed.

Swells generated by Fiona are affecting the Leeward Islands, the
northern Windward Islands, the Virgin Islands, Puerto Rico, the
northern coast of the Dominican Republic, the Turks and Caicos
Islands, and the southeastern Bahamas. These swells will continue
to spread westward across the southwestern Atlantic toward the
central and northwestern Bahamas and the east coast of the United
States through midweek. These conditions could cause life-
threatening surf and rip current conditions. Please consult
products from your local weather office. Please read the latest
High Seas Forecast issued by the National Hurricane Center at
website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the
latest NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

...TROPICAL WAVES...

A central Atlantic tropical wave has its along 45W from 04N to 15N
moving westward at 15 kt. Scattered showers and a few thunderstorms
are noted from 09N to 14N between 42W-50W.

Another central Atlantic tropical wave has its axis along 55W
from 06N to 20N. It is moving westward at about 10-15 kt. A
surface trough extends from just north of the wave to 25N53W.
Isolated showers and thunderstorms are noted within 180 nm either
side of the wave axis from 08N to 13N.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coast of Senegal near
14N17W and extends southwestward to low pressure of 1011 mb
near 09N26W and continues to 09N36W and to 09N44W. The ITCZ
extends from 09N46W to 09N54W. Scattered moderate to isolated
strong convection within 120 nm south of the trough axis between
27W-31W.

GULF OF MEXICO...

Weak surface ridging over the eastern United States extends
southwestward into the Gulf of Mexico, supporting mainly moderate
easterly winds across the central and western Gulf. Recent
observations from buoys and oil platforms show fresh northeast
winds over the NE Gulf. Fresh to locally strong northeast winds
are west of the Yucatan Peninsula, over the eastern Bay of
Campeche. Recent and current buoy observations along a with a
couple of altimeter data passes show wave heights of 2-3 ft,
except for slightly higher wave heights of 3-4 ft in the eastern
Bay of Campeche. Scattered showers and isolated thunderstorms are
over the western Bay of Campeche. Similar activity is noted in the
eastern portion of the Straits of Florida, east of 81.5W, due to
a surface trough in the area. The rest of the Gulf remains under
fairly tranquil weather conditions.

For the forecast, high pressure over the southeastern U.S. will
maintain gentle to moderate easterly breezes and slight seas the
next few days.

CARIBBEAN SEA...

Please see the Special Features section above for information on
Hurricane Fiona.

Outside of convection associated with Fiona, scattered showers
and thunderstorms are within 60 nm of the coast of Honduras.
Scattered moderate isolated strong convection associated with the
east Pacific monsoon trough is noted near the coasts of western
Venezuela, Colombia and eastern Panama, mainly south of 13N
between 72W-79W.

Fresh northeast winds are likely occurring in the Windward
Passage. Overnight ASCAT data indicates that gentle trades
prevail elsewhere. The area of winds over 20 kt and wave heights
of 7-10 ft associated with Fiona is confined to areas north of 15N
between 63.5W-71W. Lower wave heights of 1-3 ft over the western
Caribbean west of 78W. Wave heights of 4-6 ft are elsewhere over
the eastern Caribbean outside of Fiona, except for higher wave
heights of 7-10 ft due to strong east-southeast winds along the
southeast periphery of Fiona's circulation that are north of 16N
between 66W-71W.

For the forecast, Hurricane Fiona will track over the eastern
portion of the Dominican Republic this morning and emerge over the
southwestern Atlantic this afternoon. The center is forecast to
pass near or to the east of the Turks and Caicos on Tue, with
maximum sustained winds 95 kt gusts 115 kt. Fiona will gradually
strengthen as it continues to pull farther away from the Caribbean
through mid-week. Residual swell over the eastern Caribbean from
Fiona will slowly subside early this week.

ATLANTIC OCEAN...

Refer to the Special Features section above for details on
Hurricane Fiona and the tropical waves moving across the basin.

Weak low pressure of 1017 mb is analyzed near 28N46W, with a
trough extending from it southwest to near 25N50W. Overnight ASCAT
data passes indicated mainly fresh winds around and near the low,
except in its S and SW quadrants, where gentle winds are noted.
An upper-level low located near 25N47W is supporting the surface
trough attendant to the low. The base of an upper-level trough is
just to the north of the surface low. It is helping to sustain
scattered moderate convection from 28N-33N between 43W-48W.
Similar activity pivoting to the east-southeast is from 21N to 25N
between 47W-51W. This system has a low chance of tropical cyclone
formation during the next 48 hours while it moves generally
northward.

A surface trough extends across the Florida Peninsula from 31N81W
to central Florida, and continues southward to the Straits of
Florida near 24N82W. Isolated showers and thunderstorms are near
the trough over the Straits of Florida. A weak stationary front
extends from low pressure of 1013 mb that is north of the area
near 33N60W southwestward to 29N64W. Isolated showers and
thunderstorms are seen north of 28N between 54W-65W. Relatively
weak high pressure that is anchored by a 1023 mb high center
north of the area near 34N33W remains elsewhere.

Mostly moderate winds along with wave heights of 4-6 ft are
across most of the Atlantic. The exception is near Hurricane
Fiona. Per an overnight ASCAT pass, fresh to strong winds are
south of 23N between 63W-70W in association with Fiona. Wave
heights of 8 ft and higher are associated with these winds. The
overnight ASCAT data passes revealed large swaths of fresh
northeast to east trade winds from 15N to 30N between 24W-33W and
from 12N to 21N between 33W-45W. An area of fresh north winds is
off the coast of Africa from 18N to 22N between the coast and 22W.

For the forecast west of 55W, Fiona, presently inland the eastern
Dominican Republic, will gradually strengthen to a major
hurricane as it moves to near 19.4N 69.3W this afternoon, then
track north-northwestward to near 20.8N 70.3W late tonight, to
near 22.2N 71.0W Tue afternoon with maximum sustained winds 95 kt
gusts 115 kt, to near 23.6N 71.2W late Tue night with maximum
sustained winds 100 kt gusts 120 kt, the turn to the northeast
reaching near 25.1N 70.9W Wed afternoon, near 27.0N 70.2W late Wed
night with maximum sustained winds 110 kt gusts 135 kt and to
north of the forecast waters near 32.5N 66.5W late Thu night.
Fiona will weaken as it moves well northeast of the area through
Fri night. High pressure will build in the wake of Fiona.

$$
Aguirre
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