AXNT20 KNHC 132343
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
743 PM EDT Tue Aug 13 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.
Based on 1800 UTC surface analysis and satellite imagery through
Potential for Heavy Rain/Flooding in Central America: The
potential for heavy rain exists in parts of NW Colombia, Panama,
Costa Rica and Nicaragua due to favorable upper level atmospheric
conditions, now through Friday. Currently, numerous moderate to
scattered strong convection is occurring over portions of Panama
and Costa Rica. Rainfall amounts of 1 to 3 inches per day are
expected across the region, with isolated higher amounts. The
heaviest rains are likely to occur in western Panama and Costa
Rica. These rains could lead to flash flooding and mudslides in
SW Carribbean Gale Warning: A surface ridge will persist from the
central Atlantic west-southwest across the central Bahamas to the
Straits of Florida. This pattern will support gale force winds in
the Gulf of Venezuela this evening beginning at 14/0000 UTC and
ending before 14/0600 UTC. Refer to the High Seas Forecast
product at http://hurricanes.gov/text/MIAHSFAT2.shtml for details.
An Atlantic Ocean tropical wave is along 36W from 13N southward,
moving W at 10-15 knots. Model diagnostics depict the wave well at
700 mb. Scattered showers are seen from 06N-10N between 34W-40W.
An Atlantic Ocean tropical wave extends from 22N55W to 14N55W to
05N53W and is moving W at 15-20 knots. The wave model diagnostics
depict the wave well at 700 mb. The wave is embedded in dry
Saharan air, which is limiting precipitation to the north of 12N.
Scattered moderate convection is from 05N-12N between 46W-55W.
A central Caribbean Sea tropical wave is along 79/80W from 07N-
23N, moving W at 15-20 knots. Numerous moderate to scattered
strong convection is over Panama and Costa Rica, enhanced by the
East Pacific monsoon trough. Scattered showers and tstorms are
over eastern and central Cuba, Jamaica and west of the Cayman
Islands to 84W.
The monsoon trough passes through the coastal sections of Guinea-
Bissau near 12N16W to 08N33W. The ITCZ extends from 07N38W to
09N51W and continues W of a tropical wave from 08N55W to 08N59W.
Aside from the convection mentioned in the Tropical Waves section
above, scattered showers and isolated tstorms are seen within 180
nm of the ITCZ between 40W-46W. Additional showers are approaching
Trinidad and NE Venezuela.
GULF OF MEXICO…
A broad upper level ridge remains in control across the Gulf of
Mexico. On the TPW imagery, a large area of enhanced moisture is
noted over the NE Gulf. A 1012 low pressure is located near the
coast of Mississippi. This is producing scattered moderate to
isolated strong convection from 28N-31N between 87W-90W. Scattered
showers and isolated tstorms are seen from 27N-29N east of 85W,
and in the south-central Gulf from 21N-25N between 84W-92W,
including in the Yucatan Channel. No significant showers are seen
west of 92W. The ASCAT pass from late Tuesday morning shows gentle
winds across the basin.
Surface ridging will continue to dominate the Gulf waters
supporting light to moderate winds and seas generally under 5 ft.
Winds will pulse to fresh over the western Yucatan Peninsula
adjacent waters each evening associated with a surface trough.
Aside from the convection mentioned in the sections above,
scattered moderate convection is occurring over northern
Venezuela as well as the far SW Caribbean near the coasts of
Panama and Costa Rica. Scattered showers and tstorms are seen over
the Greater Antilles and the NW Caribbean, mainly north of 18N
between 75W-90W. Relatively dry mid-level air is seen over much of
the central Caribbean due to influences from Saharan dust. Strong
trades cover the south-central Caribbean with near gales near the
coast of Colombia and in the Gulf of Venezuela.
A tropical wave with axis along 79/80W will move out of the
western Caribbean late on Wed. Another tropical wave currently
located along 54W will reach the waters E of the Lesser Antilles
tonight and the eastern Caribbean on Wed morning. The passage of
these waves along with high pressure north of the area will
continue to support generally fresh to strong winds in the central
and southwest Caribbean through Fri night. Winds will briefly
reach minimal gale force in the Gulf of Venezuela this evening.
A surface ridge extends from the central Atlantic west-southwest
across the central Bahamas to the Straits of Florida. A stationary
front is along 33N from 65W westward to 79W. Scattered showers
and tstorms are seen from Cuba to 30N between 70W and Florida. To
the east, a 1026 mb high pressure centered near 33N45W remains in
control across the basin.
The surface ridge in the W Atlantic will persist through the end
of the week. This pattern will maintain mainly gentle to moderate
winds north of 22N, and moderate to fresh winds south of 22N
through most of the period. Active weather will continue across NW
waters through Wed as the remnants of a former front linger in