[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 262110 AAB
TWDAT

Tropical Weather Discussion...UPDATED
NWS National Hurricane Center Miami FL
510 PM EDT Mon Aug 26 2019

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.

...UPDATED FOR SPECIAL FEATURES...

Based on 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

Tropical Storm Dorian is centered near 12.7N 58.8W at 26/2100
UTC or 145 nm ESE of St. Lucia moving WNW at 12 kt. Estimated
minimum central pressure is 1002 mb. Maximum sustained wind
speed is 50 kt with gusts to 60 kt. Numerous moderate to
scattered strong convection is within 60 nm of the center in the
northern semicircle and 30 nm southern semicircle. Scattered
moderate convection is elsewhere within 120 nm of the center,
and extends as far as 300 nm east of the center. The west-
northwest motion is expected to continue through Tuesday night,
followed by a NW turn on Wed. On the forecast track, the center
of Dorian is expected to be near the Windward Islands this
evening and tonight and pass near or south of Puerto Rico on
Wednesday. Some strengthening is forecast, and Dorian could
become a hurricane by late Tuesday or Wednesday. See the latest
NHC forecast/advisory under AWIPS/WMO headers MIATCMAT5/WTNT25
KNHC for more details.

The area of low pressure 255 nm SE of Cape Hatteras North
Carolina has developed into Tropical Depression Six. At 26/2100
UTC, Tropical Depression Six is centered near 31.7N 72.5W,
moving E at 2 kt. Maximum sustained wind is 30 kt with gusts to
40 kt, and minimum central pressure is estimated at 1010 mb.
Scattered moderate convection extends outward to 150 nm E of the
center and 300 nm S of the center. A slow E or NE motion is
expected during the next day or so, followed by a northeast
acceleration on Wednesday. Some gradual strengthening is
possible during the next day or two, and the depression is
forecast to become a tropical storm tonight or Tuesday. See the
latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMAT1/WTNT21 KNHC for more details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave is along 34W from 20N southward,
moving W at 10 kt. Saharan dry air prevails in the wave's
environment at this time, limiting convection. Scattered showers
are from 06N-10N between 34W-36W.

A central Caribbean tropical wave is along 76W from 07N-20N,
moving W at 15-20 kt. Dry air is also noted in the wave's
environment, limiting convection at this time. Scattered showers
are noted along the wave's axis mainly north of 18N.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal Africa near 18N16W
to 10N34W to 10N49W. Besides the convection mentioned in the
tropical wave section above, scattered showers are noted 07N-09N
37W-47W. Due to the presence of Saharan dust, no significant
convection is noted north of 12N. Scattered showers and tstorms
are near the coast of Africa south of 11N between 12W-20W.

GULF OF MEXICO...

Weak surface ridging prevails across the basin. Scattered
showers are noted over the northwest Gulf north of 23N and west
of 89W. Scattered showers and tstorms are seen along the northern
Gulf from coast of Louisiana to the FL Panhandle. Scattered
moderate convection is in southern Florida from 25N85W across the
peninsula to 26N79W. This activity is supported by upper level
diffluence.

Relatively weak high pressure will continue across the area
through Fri night. The high will maintain moderate to fresh south
to southeast winds over the waters west of 90W. Winds will be
mainly light to gentle east of 90W through the period. An upper-
level trough will help trigger off scattered showers and
thunderstorms over the north-central Gulf waters through early
Tue.

CARIBBEAN SEA...

A tropical wave is moving across the basin. Refer to the section
above for details.

Fair weather prevails across the basin as a dry Saharan airmass
covers the area. Scatterometer data depicts moderate trades across
the basin, with fresh winds over the central Caribbean and the
Gulf of Honduras.

Fresh to strong trade winds over the south-central Caribbean will
increase in areal coverage through Tue, then decrease some Tue
afternoon and increase briefly increase again Tue night before
decreasing Wed. Fresh to strong east to southeast winds will pulse
over the Gulf of Honduras tonight and Tue night. Tropical Storm
Dorian is near 12.3N 57.7W 1002 mb at 11 AM EDT moving WNW at 12
kt. Maximum sustained winds 50 kt gusts 60 kt. Dorian will move to
12.9N 59.4W this evening, 13.9N 61.4W Tue morning, strengthen to
a hurricane near 15.1N 63.5W Tue evening, reach near 16.4N 65.6W
Wed morning and near 17.7N 67.6W Thu morning. Dorian will move
inland over eastern Hispaniola early Thu and weaken back to a
tropical storm near 22.0N 72.6W early on Fri, then track to
northwest while slowly strengthening as it reaches the vicinity of
the NW Bahamas on Sat.

ATLANTIC OCEAN...

Refer to the Special Features section above for details on T.S.
Dorian and the surface low over the west Atlantic.

Refer to the section above for details on the tropical wave moving
across the eastern Atlantic.

A 1010 mb surface low is centered over the west Atlantic near
31N72W. A surface trough extends from the low to 26N78W.
Scattered moderate isolated strong convection is noted 250 nm SE
of the trough or from 24N-31N between 69W-76W. To the east, a
1018 mb high is centered over the west-central Atlantic near
26N59W.

The low pressure will slowly lift northeastward through Wed,
while the trough gradually shifts eastward across the northern
waters and dissipates by early Thu. Otherwise, gentle to moderate
SE winds will continue across the area. Tropical Storm Dorian,
currently in the tropical Atlantic, is forecast to move across the
eastern Caribbean Sea as a hurricane by the middle of the week
and near the far southern waters as a tropical storm by Fri night.
Expect increasing winds and building seas for those waters
affected by Dorian.

$$

Hagen
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