696
axnt20 knhc 221746
twdat
Tropical weather discussion
NWS National Hurricane Center Miami FL
205 PM EDT Tue may 22 2012
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 1200 UTC surface analysis and satellite imagery
through 1700 UTC.
...Special features...
As of 1500 UTC...Tropical Depression Alberto was downgraded to a
Post-tropical low. The low is centered at 33.1n 74.0w...or about
150 nm SSE of Cape Hatteras North Carolina...and about 255 nm
SSE of Norfolk Virginia. It is moving NE at 15 kts with maximum
sustained wind speeds of 30 kts and gusts to 40 kts. The minimum
sea level pressure is 1008 mb. Strong shear will continue to
weaken the system which currently only has a small area of
showers/thunderstorms associated with it within 120 nm NE of the
center. Please read the latest NHC forecast/advisory under
AWIPS/WMO headers miatcmat1/ wtnt21 knhc...and the public
bulletin miatcpat1/wtnt31 knhc for more details.
...Tropical waves...
A tropical wave is along 13n24w to 3n26w moving W near 12kt. The
wave coincides with a surge of deep layer moisture present in
total precipitable water imagery. Dust enhancement imagery also
indicates that there is a clearing of the dust surrounding the
wave. Scattered moderate convection is from 3n-5n between
26w-28w.
A tropical wave extends from 15n46w to 7n49w moving W near 10-15
kts. This wave also coincides with a nwd surge in deep layer
moisture evident in total precipitable water imagery. Scattered
moderate/isolated strong convection is restricted to the ITCZ
region from 8n-10n between 47w-50w.
...The ITCZ/the monsoon trough...
The monsoon trough extends across W Africa and ends at the coast
of senegal at 17n16w. The ITCZ continues on the W side of the
tropical wave near the coast of Africa along 4n27w 5n37w 8n50w
7n59w. Scattered moderate convection is within 50 nm N of the
axis between 30w-34w...and within 100 nm N of the axis between
51w-56w.
...Discussion...
The Gulf of Mexico...
dry air aloft around the base of an upper level trough centered
over Tennessee is providing fair conditions across much of the
Gulf of Mexico. The upper trough supports a weak surface trough
extending from NE Florida near 31n82 along 29n87w to SW
Louisiana at 30n93w supporting a few clusters of
showers/thunderstorms along the axis...as of 1500 UTC. A weak
surface ridge around a 1017 mb high near 26n93w is producing
light anti-cyclonic flow in the NW Gulf with strong NE winds
across the SW Gulf. Total precipitable water imagery indicates
some higher moisture values across the se Gulf associated with
an area of low pressure in the NW Caribbean. No
showers/thunderstorms are currently impacting this area...but
could be possible over the next few days as this system moves
NE. Surface ridging will continue over the remainder of the
basin for the next 24 hours providing fair weather.
The Caribbean Sea...
broad cyclonic surface flow covers the NW Caribbean around a
1009 mb low near 18n86w. A surface trough extends through the
low center from NW Honduras at 16n87w towards wrn Cuba along
20n83w 24n82w. This area also lies underneath diffluence aloft
between an upper level trough over the Gulf of Mexico and an
upper level ridge extending from Nicaragua across Hispaniola and
into the W Atlc. This pattern is helping produce numerous
showers/thunderstorms from 14n-18n between 78w-82w...and from
18n-22n between 79w-83w. Scattered showers/isolated
thunderstorms are also across the area from 10n-22n between
78w-86w. This system is expected to move NE over the next
several days. The ern Caribbean is experiencing mostly fair
weather due to dry air aloft around the E side of the
aforementioned upper level ridge. Tradewind flow of 15-20 kts
covers much of the basin besides near the area of low pressure
in the wrn Gulf. Expect moist conditions to remain over the wrn
Gulf for the next several days with fair conditions over the ern
Caribbean.
The Atlantic Ocean...
diffluence aloft between an upper level trough over the se conus
and an upper level ridge extending from the Caribbean across
Hispaniola to 37n51w is supporting scattered showers/isolated
thunderstorms N of Cuba to 26n between 73w-80w...and N of 26n
between 61w-75w. The upper ridge also supports a broad surface
ridge around a 1028 mb high near 32n54w which is providing fair
conditions across the central Atlc. An upper level trough
extends from 31n38w to 16n58w while an upper level ridge covers
the tropical ern Atlc centered near 15n28w. Visible satellite
imagery along with GOES-r dust enhancement imagery indicates
that an area of dust extends from the coast of Africa to 40w
with clearing around the tropical wave near the coast of Africa.
For additional information please visit
http://www.Hurricanes.Gov/marine
$$
Walton
