037 axnt20 knhc 260002 twdat Tropical weather discussion NWS TPC/National Hurricane Center Miami FL 805 PM EDT Fri Jul 25 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. ...Tropical waves... A tropical wave has been introduced onto the 25/1800 UTC surface analysis and is along 19w S of 20n moving W near 15 kt. Observations from dakar senegal indicate that wave has passed the area. Hovmoller diagram data over the past couple of days has also depicted the westward movement of this wave and its associated convective activity. Scattered moderate convection is from 13n-15n between 15w-19w. Scattered showers also linger along the W African coast from 11n-17n. A strong tropical wave is along 42w/43w S of 24n moving W near 15-20 kt. A 1012 mb surface low remains associated with the wave near 18n and continues to move slowly towards the WNW. Although upper-level winds are currently not favorable for development... the wave may move into an environment more conducive for organization in a couple of days. Tight pressure gradient between the low and the Atlc surface high will produce an increase in winds across the central Atlc through the weekend. An area of scattered moderate convection is from 19n-21n between 40w-43w. A tropical wave is along 68w moving W near 20 kt across the ern Caribbean Sea. The wave extends from wrn Puerto Rico to north central Venezuela. While currently under strong to moderate subsidence/dry air aloft...no deep convection is associated with the wave across Caribbean Sea waters. Widely scattered moderate convection is across nrn Venezuela and most likely embedded within the ITCZ. A tropical wave is across central Guatemala along 90w S of 16n moving W near 10 kt. This wave lies mostly in the E Pacific region. For more information refer to the ern Pacific tropical weather discussion...twdep. ...The ITCZ... ITCZ axis is centered along 10n21w 8n27w 13n36w 13n40w 11n46w to inland across nrn South America near 7n69w. Clusters of widely scattered moderate convection are from 6n-11n between 22w-26w. ...Discussion... Gulf of Mexico... tropical disturbance Dolly is still generating locally heavy rain over portions of south Texas and north central Mexico. At 25/2100 UTC...it was located near the Texas/Mexico border...just to the south of the Texas Big Bend near 29.9n 105.3w. Estimated minimum central pressure is 1009 mb. Maximum sustained winds are 25 kt with gusts to 35 kt. The disturbance is moving WNW at 13 mph. The Gulf of Mexico is under the influence of a surface ridge with a 1022 mb high located over the NE Gulf near 28n87w. Generally light E-se winds are observed across the central and wrn Gulf as high pressure ridge builds slowly west across the nrn Gulf waters through the weekend. Mainly light and variable winds dominate the ern Gulf this evening. Aloft...an broad upper anticyclone anchored over NE Texas is producing NE to E winds over the N Gulf waters. This is aiding in generating scattered showers with embedded tstms across the nern Gulf NE of a line from New Orleans Louisiana to Fort Myers Florida. An upper-level low located across The Isthmus of Tehuantepec extends troughing across the Yucatan Peninsula and Straits of Florida. Scattered showers and isolated tstms are across srn Mexico...the Yucatan Peninsula and wrn Cuba in association with this feature. Caribbean Sea... narrow upper-level troughing extends from South Florida across wrn Cuba and the Yucatan Peninsula. An upper low is embedded in this trough generating scattered showers and tstms across srn Mexico and the Yucatan Peninsula. An upper-level high is positioned south of Jamaica and dominates the remainder of the basin with moderate to strong subsidence and an implied dry stable air mass. S-SW flow between the above mentioned upper level features is drawing sufficient upper level moisture from the E Pacific region into the NW Caribbean Sea across Central America..the Yucatan Channel and wrn Cuba. A tropical wave is moving westward across the ern Caribbean. See tropical wave section. Moderate to strong trade winds of 15 to 25 kt are observed across the south-central Caribbean this evening. Atlantic Ocean... a 1029 mb high located near 38n57w extends surface ridging across much of the central Atlc and wrn Atlc E of 65w. Upper level troughing W of 65w with an embedded upper low near 27n73w and a weak surface trough across the NW Bahamas is generating isolated showers over the NW and central Bahamas. A second upper level low is near 26n61w producing isolated shower activity from 21n-27n between 57w-64w. Strong subsidence and a dry stable atmosphere are in place over the central Atlc...mainly between 45w-57w with an upper anticyclone located near 18n55w. In the ern Atlc...surface ridging extends E of 40w anchored on a 1022 mb surface high centered near 32n26w. $$ Huffman

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