022 
axnt20 knhc 182348
twdat 
Tropical weather discussion
NWS TPC/National Hurricane Center Miami FL
805 PM EDT Fri Jul 18 2008
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...meteorological analysis...weather
observations...and radar.
Based on 1800 UTC surface analysis and satellite imagery through 
2315 UTC.
...Special features...
Tropical Storm Bertha was upgraded to hurricane again at 18/2100 
UTC. Hurricane Bertha is centered near 37.6n 50.6w at 18/2100 
UTC moving NE at 19 kt. Estimated minimum central pressure is 
989 mb. Maximum sustained wind speed is 65 kt with gusts to 80 
kt. Please see the latest NHC forecast/advisory under AWIPS/WMO 
headers miatcmat2/wtnt22 knhc and the public advisory under 
miatcpat2/wtnt32 knhc for more details. The eye has become 
better-defined with deep convection increasing around a 
consolidating eyewall...however it is not expected to remain a 
hurricane for too long as it will be moving over cooler waters 
by this time on Sat and then will become extra-tropical on sun. 
Scattered moderate convection is within 120 nm over the N 
semicircle and within 90 nm over the S semicircle.
A broad area of lower pressure off the Georgia/South Carolina 
coast centered by a 1013 mb low near 31.5n80.5w with a surface 
trough extending SW across the Florida Peninsula into the Gulf 
of Mexico. This system is becoming better defined and a tropical 
depression could form later tonight/early Sat. All interests 
along the coasts of Georgia...South Carolina...and North 
Carolina should monitor the progress of this system. Locally 
heavy rainfall and gusty winds are possible in these areas 
during the next couple of days as this system moves slowly 
northeastward near the coast. Scattered showers/thunderstorms 
are currently offshore from 30n-32n between 77w-80.5w. Scattered 
showers and possible isolated thunderstorms are N of 28n W of 
76w to inland over se U.S. 
Tropical wave is along 71w/72w S of 18n with a 1008 mb low along 
the wave axis near 15n moving WNW 15-20 kt. A tropical cyclone 
could form at any time as the system moves toward the WNW. All 
interests in Jamaica...the Cayman Islands...and the northwestern 
Caribbean Sea should continue to monitor the progress of this 
system. Locally heavy rainfall is moving across Hispaniola and 
will spread across Jamaica later this evening. Scattered 
showers/thunderstorms are N of 14n to over Hispaniola between W 
Puerto Rico and E Cuba/Windward Passage. Scattered 
showers/isolated thunderstorms cover the remainder of between 
66w-78w. 
...Tropical waves...
Tropical wave is along 50w S of 17n moving W 10-15 20 kt. High 
amplitude inverted-v curvature is observed on satellite imagery 
with no associated showers or deep convection. 
Tropical wave is along 86w/87w S of 21n with a 1007 mb low along 
the wave inland over Honduras. This system is not expected to 
become a tropical depression. However...this system is producing 
gusty winds over portions of the northwestern Caribbean 
Sea...and locally heavy rains are expected to continue over 
portions of Honduras...Nicaragua...Belize and Guatemala for the 
next day or two. These rains could cause life-threatening flash 
floods and mudslides. Scattered showers/isolated thunderstorms 
are S of 20n W of 83w to inland over Central America and the 
Yucatan Peninsula. 
The ITCZ...
ITCZ axis is centered along 13n16w 6n28w 10n48w 10n62w. 
Scattered moderate/strong convection is from 3n-7n between 
31w-33w. Clusters of scattered moderate/isolated strong 
convection are from 4n-10n between 20w-30w and from the Equator 
to 2n between 35w-40w. 
 
Discussion...
Gulf of Mexico...
the Gulf has become quite tranquil compared to the past few days 
as the 1013 mb low off the Georgia/South Carolina continues to 
move NE and away from Florida. A surface trough does extend 
from this low across the Florida Peninsula from St. Augustine to 
Tampa to a weak 1016 mb low near 27n87w. Isolated showers dot 
the area N of the surface trough. An upper low is along the 
coast of Texas near Corpus Christi covers the W Gulf. An upper 
ridge extends from the Yucatan to se Louisiana covering the 
central Gulf and providing enough diffluence aloft to generate 
scattered clusters of showers/isolated thunderstorms N of 27n 
from 88w-95w. Scattered showers/thunderstorms associated with 
the tropical wave over Central America /W Caribbean are moving 
off the the W coast of the Yucatan Peninsula within 60 nm along 
the coast in the E Bay of Campeche. Otherwise the remainder of 
the Gulf remains tranquil this evening. 
Caribbean Sea...
the main focus this evening in the Caribbean is the E Caribbean 
tropical wave along 71w/72w. See special features above. 
Interests in the W Caribbean see the tropical wave section above 
for the tropical wave along 86w/87w. An upper low is centered 
over central Cuba near Camaguey covering the N/central Caribbean 
to over the Bahama Islands. This is enhancing the showers/ 
isolated thunderstorms that have developed over W Cuba moving S 
into the Caribbean W of the Isle of Youth to the Yucatan 
Channel. Scattered showers/thunderstorms are inland along the 
immediate coast of Panama and Costa Rica in association with the 
close proximity of the ITCZ as it enters the E Pacific region.  
Most noticeably is the lack of showers or clouds over E 
Caribbean E of 65w to across the Lesser Antilles and Virgin 
Islands. 
Atlantic Ocean...
the main focus for the W Atlc is the 1013 mb low off Georgia/ 
South Carolina coast and Hurricane Bertha N of the region...see 
special features above. A shortwave upper trough is over the 
N/central Atlc N of 28n from 52w-60w with a surface trough 
extending from 31n56w to 28n64w generating scattered showers/ 
isolated thunderstorms within 125 nm S of the trough axis. An 
upper low is over central Cuba to over the Bahama Islands with a 
small upper high to the NE centered near 30n62w. This providing 
enough diffluence aloft to generate scattered clusters of 
showers/isolated thunderstorms from 28n-30n between 64w-68w. 
Also at the surface is a weak 1020 mb high near 28n73w. Another 
small upper low is in the central Atlc near 26n48w. A large 
upper high covers the remainder of the Atlc anchored near 
27n28w. Strong subsidence and dry stable air covers the Atlc E 
of 50w with a surface ridge also covering the E Atlc E of 50w 
anchored by 1030 mb high N of the Azores. 
$$
Wallace

		
		

		View Tropical Weather
		View Hurricane Archive