000 AXNT20 KNHC 221722 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 105 PM EST THU DEC 22 2016 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 1645 UTC. ...SPECIAL FEATURES... .None. ...THE ITCZ/THE MONSOON TROUGH... The ITCZ extends from 07N14W to 04N42W. Scattered moderate convection exists within 120 nm of the ITCZ between 20W and 30W. Scattered moderate to isolated strong convection is noted within 180 nm of the ITCZ from 30W to 42W. ...DISCUSSION... ...THE GULF OF MEXICO... A 1026 mb high is centered near where Georgia, Alabama, and Florida meet. South of the high, the north-south pressure gradient is weak across the Gulf and winds are generally weak NE to E with some cool air advection still occurring from a frontal passage a couple of days ago. The exception is some weak southeasterly winds in the northwestern Gulf of Mexico ahead of a cold front currently over southern Texas. No deep convection is occurring today over the Gulf and surrounding land masses due to the stable conditions. However, there are some low-topped showers occurring along the Texas coast and the Florida Keys, as seen in the WSR-88D radar imagery. There is extensive low cloud cover within the upslope flow along the east side of the Sierra Madre Oriental mountains in northeastern Mexico and there may be some stratiform precipitation embedded within as well. The front over Texas does not reach into the Gulf much at all, as easterly and southeasterly winds pick up over the next two days. Winds, however, generally will be 10-20 kt. Except for some shower activity near the Texas coast, most of the Gulf of Mexico should remain rain-free during the next two days. ...THE CARIBBEAN SEA... High pressure north of the Caribbean and low pressure over northern South America is inducing a moderate north-south pressure gradient over the Caribbean Sea today. NE to E tradewinds are generally 15-25 kt with highest winds occurring just south of Hispaniola. Scattered moderate and isolated strong convection is noted over the Lesser Antilles this morning, which may be related to a weak upper-level low that was located just north of Puerto Rico this morning along with large amounts of total precipitable water as seen in the TPW imagery. Guadeloupe reported 0.59 inches of rain and Trinidad reported 0.31 inches of rain over the last 24 hours ending at 12 UTC. As the upper-low fills, the potential for deep convection over the Lesser Antilles should diminish. However, ample low-level moisture may allow some rainfall from low-topped showers especially in the Lesser Antilles, northernmost South America, and eastern Central America. The NE to E tradewinds should amplify some on Saturday, especially in and downwind of the Mona Passage and Windward Passage. ...HISPANIOLA... Presently Hispaniola has fair weather and light winds. There is a slight chance of low-topped showers along the eastern slopes and higher terrain during the next 48 hours. ...THE ATLANTIC OCEAN... As of 1500 UTC, a dissipating cold front had pushed southeastward into the central Bahamas. This is indicated by the drop in dewpoint and temperature, as well as a shift in winds to be from the northeast. No significant convection is associated with this feature and the front is expected to dissipate shortly. A new cold front will push through the water south of Bermuda and NE winds will reach about 20-25 behind the front during the next couple of days. The cold front should not be very convectively active, due to the lack of significant moisture ahead of the front. Scattered moderate and isolated strong convection is noted east of the Lesser Antilles this morning, which may be related to a weak upper-level low that was located just north of Puerto Rico this morning along with large amounts of total precipitable water as seen in the TPW imagery. As the upper-low fills, the potential for deep convection should diminish during the next day. Elsewhere of the tropical north Atlantic, a 1037 mb high near the Azores is helping to promote 15-25 kt NE tradewinds across the Atlantic. These should diminish some as the high weakens during the next two days. For additional information please visit http://www.hurricanes.gov/marine $$ Landsea