000 AXNT20 KNHC 211634 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1234 PM EDT Tue Mar 21 2017 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 1545 UTC. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 10N14W to 03N20W. The Intertropical Convergence Zone axis extends from 03N20W to the Equator near 25W. Widely scattered moderate convection is S of 06N between the Prime Meridian and 07W. Isolated moderate convection is S of 03N between 13W-21W...and S of 05N between 47W-54W. ...DISCUSSION... GULF OF MEXICO... NW flow aloft prevails over the Gulf providing dry air and stable conditions filtering to the surface in the form of a ridge anchored by a 1022 mb high centered near 26N90W. The ridge extends eastward across portions of the SW North Atlc anchored by another 1022 mb high centered across the southern Florida peninsula. Gentle to moderate anticyclonic winds accompany the ridge as noted on recent ASCAT data. The high is forecast to remain nearly stationary across the central Gulf waters with little change in the overall wind pattern through Wednesday. By Thursday...the ridge will weaken slightly and begin moving NE as E-SE winds increase into fresh to strong levels Thursday night into Friday as an area of low pressure develops across the Front Range and central Plains. CARIBBEAN SEA... Broad upper level troughing is noted on water vapor imagery over the NW Caribbean while southwesterly flow aloft to the east of the troughing prevails over the eastern Caribbean. Dry and stable air overall is providing for a lack of any significant deep convection and mostly tranquil surface conditions this afternoon. A few areas of isolated showers however are noted on satellite imagery across the far southwestern waters S of 16N W of 80W... including inland portions of Honduras...Nicaragua...and Costa Rica. A stationary front terminates across north-central Hispaniola with isolated showers occurring N of 17N between 65W- 74W. Otherwise...moderate to occasional fresh trades prevail and are expected to persist through Thursday night. ...HISPANIOLA... The tail end of a stationary front extends from the central Atlc near 24N60W SW to the northern coast of Hispaniola near 20N71W. Low-level moisture convergence associated with the front continues to provide focus for isolated showers generally N of 17N between 68W-74W...including portions of the adjacent coastal waters. The front is expected to become diffuse by late Wednesday...however any lingering remnant boundary or surface troughing will provide a slight probability of isolated shower activity through the remainder of the week. ATLANTIC OCEAN... Broad middle to upper level troughing is noted on water vapor imagery over the SW North Atlc generally N of 26N in response to an upper level low centered N of the area supporting a cold front analyzed into the discussion area near 32N52W. The cold front continues SW to 24N60W then becomes stationary to the northern coast of Hispaniola. Widely scattered showers and isolated tstms are occurring N of 25N between 48W and the boundary. Isolated showers are occurring elsewhere within 180 nm either side of the stationary front. The remainder of the SW North Atlc region is under the influence of a surface ridge anchored by a 1022 mb high centered across the southern Florida peninsula near 27N81W. Mostly light to moderate anticyclonic flow is associated with this ridge. Farther east...the remainder of the central waters and eastern Atlc is under the influence of another surface ridge anchored by a 1035 mb high centered across the Azores near 40N27W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN