000 AXNT20 KNHC 121138 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Jan 12 2021 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 0600 UTC surface analysis and satellite imagery through 1115 UTC. ...SPECIAL FEATURES... Caribbean Sea Gale Warning: The pressure gradient between high pressure north of the area and the Colombian/Panamanian low is currently supporting gale force winds offshore Colombia. Overnight ASCAT highlighted minimal gale force winds roughly from 11N to 13N between 74W-76W. These winds will diminish below gale force by 1500 UTC this morning. Wave heights with these winds are in the range of 12-14 ft. These winds will pulse back up to gale force tonight, then diminish to strong speeds early Wed. These winds will diminish Thu through Sat as the high pressure weakens and shifts east. Wave heights will also subside Thu through Fri. Please read the latest High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for details. ...MONSOON TROUGH/ITCZ... The monsoon trough axis enters the Atlantic Ocean along the coast of Guinea near 10N14W and continues southwest and west to 04N23W, where overnight scatterometer data indicated that it transitions to the ITCZ to 04N30W to 03N40W and to the coast of Brazil near 01N50W. Scattered moderate to isolated strong convection is within 180 nm north of the ITCZ between 30W-37W. Scattered moderate convection is within 60 nm north of the ITCZ between 28W-30W. GULF OF MEXICO... As of 12/0900 UTC, a cold front extends from northern Florida to 25N86W and to the northwest part of the Yucatan Peninsula, where it becomes stationary to the coast of Mexico at 19N92W. Overnight ASCAT data showed fresh to strong northwest to north winds over much of the waters west of the front. Areas of rain along with scattered showers are on both sides of the front, covering the central and southeastern Gulf of Mexico. These showers are being enhanced by upper-level divergence. Very dry and stable air leading to clear skies is present over the NW and west- central Gulf sections Strong northwest to north are confined to the far SW Gulf as also depicted by the ASCAT data. The ASCAT data indicates that a surface trough has formed offshore of Veracruz Mexico, with strong northwest winds along that coast. For the forecast, the cold front will weaken as it slowly reaches the far southeastern Gulf tonight. It will then dissipate over the Straits of Florida through Thu. Fresh to strong north winds behind the front will diminish to mainly fresh winds Tue. The coastal trough will maintain strong to near gale force northwest winds along the coast of most Mexico through Wed before diminishing Wed night as high pressure building across the northern Gulf allows for winds and seas to diminish elsewhere. Looking ahead, another front will move into the northern Gulf Fri, with fresh winds and building seas following the front as it moves over the eastern Gulf through Sat. CARIBBEAN SEA... A Gale Warning is in effect near the coast of Colombia. Please see the Special Features section for more information. Elsewhere, overnight ASCAT data passes revealed fresh to strong trade winds over the central part of the sea, with the exceptions being: on the periphery of the ongoing gale force winds where winds to near gale force were noted and over the eastern Caribbean, where trade winds are of moderate to fresh speeds. Moderate to fresh northeast to east trade winds are over the northwestern part of the sea. Pockets of scattered showers and isolated thunderstorms moving in a general northward direction are over the western Caribbean west of about 80W, enhanced by upper level-divergence that is over that part of the Caribbean ahead of a mid to upper-level trough presently extending into the northwestern Caribbean from the eastern Gulf of Mexico. Broad mid to upper-level ridging is present over the basin, with the anticyclone center noted over northern Venezuela. High pressure north of the area will maintain fresh to strong trade winds across the eastern and central Caribbean through Wed night, with speeds reaching gale force off Colombia overnight tonight into early Wed. Winds over the central Caribbean will diminish and seas will subside Thu through Sat as the high pressure weakens and shifts eastward. E swell will propagate from the central Caribbean into the southwestern Caribbean through Wed, then subside through Thu. ATLANTIC OCEAN... High pressure of 1026 mb centered about 200 nm southwest of Bermuda dominates the western Atlantic. However, a stationary front extends from 32N79W to across southeastern Georgia and to a 1019 mb low pressure near Valdosta, Georgia. A cold front extends from the low south-southwestward over the eastern Gulf of Mexico. This weakening cold front will move off the northeast Florida coast this morning and reach from near Bermuda to the Straits of Florida by early Wed. The front will stall and start to dissipate Thu from near 32N65W to the southern Bahamas, ahead of a reinforcing front moving across the waters north of 27N that will move east of 65W through Fri. Winds and seas will increase north of the Bahamas late Fri ahead of a strong cold front expected to move off the Florida coast Sat. A cold front extends from near 32N39W to 27N49W and to 25N58W, where it becomes stationary to 22N72W to 24N60W and weakens to near eastern Cuba. The stationary portion of this front west of 60W will dissipate today. Mainly fresh southwest winds were highlighted by an overnight ASCAT pass to be within about 120 nm east of the front and north of 29N. A sharpening upper-level trough is over the front and is assisting in the fast development of large clusters of scattered showers and thunderstorms that are within 180 nm east of the front north of 29N. This activity may be accompanied by strong gusty winds and very rough seas as it quickly moves eastward. Patches of broken to overcast low clouds, with possible isolated showers, are along and near the remainder of the cold front as well along and near the stationary front. Abundant atmospheric moisture is on the increase over the western half of the area ahead of the Gulf of Mexico cold front. This moisture is being steered by mid to upper-level southerly flow that is present around the western periphery of broad anticyclonic flow found across the Caribbean Sea, the western Atlantic and over the western part of the central Atlantic. Expect for increasing shower activity over the western part of the area through Wed. Over the far eastern Atlantic, strong high pressure is present per the 06Z surface analysis. This high pressure is anchored by a strong 1030 mb high center located well north of the area at 40N16W. The associated tight gradient is leading to fresh to strong trade winds to exist from 06N to 22N between 47W and the coast of Africa. Wave heights due these winds are in the 8-10 ft range. This area of winds will slowly diminish through the end of the week, with corresponding wave heights subsiding. $$ Aguirre