000 AXNT20 KNHC 221740 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1240 PM EST Sun Dec 22 2019 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 1720 UTC. ...SPECIAL FEATURES... For all three of the special features below, see the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for further details. NORTHEASTERN GULF OF MEXICO GALE WARNING... A complex 1012 mb surface low pressure system centered in the NE Gulf of Mexico near 29N87W is currently producing gale force winds east 87W and north of 26N, according to the latest ASCAT pass. Winds in the northeastern Gulf should decrease to below gale force during the late afternoon or early evening hours today. SOUTHWESTERN GULF OF MEXICO GALE WARNING... A tight pressure gradient between the aforementioned low pressure and high pressure over Mexico is leading to gale force winds in the southwest corner of the Gulf of Mexico, south of 20N and west of 95W. The winds are forecast to decrease to below gale force by early this afternoon. WESTERN ATLANTIC OCEAN GALE WARNING... Gale force winds are expected to begin this afternoon for the Atlantic waters offshore Georgia and northern Florida, mainly north of 30N between 78W-81W. This is due to a strong pressure gradient between the low pressure in the NE Gulf of Mexico and a 1030 mb high pressure near 36N66W. The gales will migrate slightly eastward during the day on Monday, remaining north of 30N between 75W-79W. The gales are expected to end Monday evening for the waters south of 31N. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of Sierra Leone near 07N12W to 07N16W. The ITCZ continues from 07N16W to 04N21W to 02N37W to 01N49W. Scattered moderate convection is seen from 02N-05N between 34W-46W and from 03N-07N between 46W-54W. Isolated moderate convection is from 02N-06N between 19W-34W. GULF OF MEXICO... Two Gale Warnings are over the Gulf of Mexico. See section above for details. A potent upper-level disturbance over Louisiana is fueling a strengthening surface low pressure system over the NE Gulf of Mexico, described below. A 1012 mb surface low is over the NE Gulf of Mexico near 29N87W. A cold front extends southward from the low to 27N87W. A stationary front continues from 27N87W to 22N87W. A warm front extends eastward from the low to the big bend of Florida near 29N83W to Jacksonville Florida. Numerous moderate with embedded isolated strong convection is within the area bounded by 31N87W to 25N86W to 29N81W to 31N81W to 31N87W, including much of northern Florida and the NE Gulf of Mexico. A second, weaker surface low of 1015 mb is west of Key West near 25N83W. A surface trough extends SSW from the low to western Cuba near 22N84W to 20N86W. A warm front extends E from the low to near Key Largo Florida. Numerous moderate with embedded isolated strong convection is to the east of the low along the warm front from 24N-27N between 81W-83.5W, including over portions of SW Florida. Isolated to scattered moderate convection is elsewhere from the north coast of western Cuba to Lake Okeechobee between 80W-85W. Winds and seas will diminish in the basin as the trailing cold front sweeps southeast of the Gulf tonight and the low lifts northeast toward the Georgia coast through late Mon. Weak high pressure sets up in the wake of the front over the western Gulf through mid week. Looking ahead, winds may increase over the northeast Gulf by late Thu as a weak front approaches the region. CARIBBEAN SEA... A surface trough extends from a 1014 mb low near 25N84W to western Cuba near 22N84W to 20N86W. Scattered moderate with isolated strong convection is along and within 90 nm east of the trough axis. In the far SW Caribbean, the east Pacific monsoon trough is inducing scattered moderate with isolated strong convection south of 11N and west of 76W, including over portions of Panama and southeastern Costa Rica. GOES-16 low and mid-level water vapor channels show that dry air covers the eastern and central Caribbean Sea. The dry air is due to mid-level anticyclonic flow and sinking motion. The latest ASCAT pass shows fresh winds over the central Caribbean, with strong winds in the south-central Caribbean. A stationary front currently extends from a 1012 mb low in the NE Gulf of Mexico to near 22N88W. This front will become a cold front and will move through the Yucatan Channel and into the far northwest Caribbean later today. The front will reach from the central Cuba to the Gulf of Honduras by early Mon from eastern Cuba to northeast Nicaragua by early Tue, before stalling and weakening from Windward Passage to 13N81W through mid week. Some coastal flooding is possible along the north coast of western Cuba, including Havana, late Mon into early Tue, due to fresh to strong NW winds behind the front over the eastern Gulf of Mexico. Fresh to strong winds will also follow the front over the western Caribbean. Elsewhere, the front and its parent low pressure will shift into the western Atlantic to the north of the area, displacing the subtropical ridge and allowing moderate trade winds by mid to late in the week. ATLANTIC OCEAN... A 1012 mb low pressure in the NE Gulf of Mexico extends a warm front to near Jacksonville Florida and just offshore the Georgia coast. Scattered moderate convection is over the Atlantic waters north of 29N and west of 69W, with isolated convection from 28N-29N. Gale force winds are expected to begin this afternoon offshore of northern Florida and Georgia. See section above for details. Fresh to strong winds already cover the entire area north of 20N west of 70W, with near gales north of 29N west of 78W. A cold front passes through 32N37W to 26N46W to 24N59W. A stationary front continues from 24N59W to 23N71W to Key Largo Florida. Scattered moderate convection extends from the front to 28N, and west of 73W, including the northwest Bahamas. The latest ASCAT pass shows strong winds on both sides of the front north of 30N, between 35W-44W. A 1028 mb high is centered near 33N17W, leading to ridging over the eastern Atlantic. Deepening low pressure currently over the northeastern Gulf of Mexico will move toward the Georgia coast by late Mon, with a trailing cold front moving off the east coast of Florida. SE winds will increase to gale force by late today off northeast Florida ahead of the approaching low and front. The front will continue to sweep eastward, reaching from 31N72W to western Cuba by early Tue as the low slowly moves toward 31N76W. The low pressure will weaken little as moves toward 29N65W by early Wed, with the front extending to the Windward Passage. Looking ahead, winds and seas diminish across the region after late Wed as the low and front move farther east and weaken. $$ Hagen