1. Heavy rainfall will impact areas across southern and central Louisiana, southern Mississippi, far southern Alabama, and the western Florida Panhandle through early Friday. Significant rainfall amounts are expected, potentially resulting in areas of life-threatening flash and urban flooding across these areas. Widespread minor to isolated moderate river flooding is also possible.

2. Storm surge inundation along the coasts of upper Texas and southwestern Louisiana will gradually diminish into tonight.

3. Tropical storm conditions in the warning area long portions of the upper Texas and southwestern Louisiana coasts will gradually subside by this evening.

CHANGES WITH THIS ADVISORY: The Storm Surge Warning and Storm Surge Watch have been discontinued. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for...
- High Island Texas to Cameron Louisiana A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office.

Key messages for Nicholas can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC and on the web at hurricanes.gov/graphics_at4.shtml?key_messages

RAINFALL: Nicholas is expected to produce additional rainfall amounts of 5 to 10 inches across portions of southern and central Louisiana, southern Mississippi, far southern Alabama, and the western Florida Panhandle through early Friday, with isolated storm totals of 20 inches possible from southern Louisiana to the far western Florida Panhandle. Life threatening flash flooding impacts, especially in urban areas, are possible across these regions. Widespread minor to isolated moderate river flooding is expected across portions of the upper Texas Gulf Coast and southern Louisiana and Mississippi. For the latest rainfall reports and wind gusts associated with Tropical Storm Nicholas see the companion storm summary at WBCSCCNS4 with the WMO header ACUS44KWBC or at the following link https://www.wpc.ncep.noaa.gov/discussions/nfdscc4.html

STORM SURGE: The combination of a storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... San Luis Pass to Intracoastal City, LA...1 3 ft Sabine Lake and Calcasieu Lake...1 3 ft Galveston Bay...1 3 ft Storm surge levels will gradually subside into this evening. For information specific to your area, please see products issued by your local National Weather Service forecast office.

WIND: Tropical storm conditions are expected to continue along the Louisiana and upper Texas coasts this afternoon, and gradually diminish by this evening.

TORNADOES: A tornado or two will be possible this afternoon into tonight across southern Louisiana.

SURF: Swells generated by Nicholas will continue affecting portions of the northwest Gulf coast this afternoon and gradually subside this evening. These swells are likely to cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 400 PM CDT (2100 UTC), the center of Tropical Storm Nicholas was located by Doppler radars, satellites, and surface observations near latitude 29.6 North, longitude 94.6 West. Nicholas is moving toward the east northeast near 6 mph (9 km/h) and this general motion should continue through tonight. An eastward turn is expected over Louisiana by Wednesday. Little motion is anticipated on Thursday. NOAA Doppler weather radar and surface observations indicate that maximum sustained winds remain near 40 mph (65 km/h) with higher gusts. Gradual weakening is forecast during the next couple of days, and Nicholas is forecast to become a tropical depression this evening and degenerate into a remnant low on Wednesday or by early Thursday. Tropical storm force winds extend outward up to 160 miles (260 km) from the center. A NOAA Ocean Service observing station at Calcasieu Pass, Louisiana, recently reported a 1 minute sustained wind of 36 mph (57 km/h) and a gust to 43 mph (69 km/h). The estimated minimum central pressure is 1003 mb (29.62 inches) based on nearby surface observations.

Doppler weather radar data from Houston and Lake Charles, along with surface observations, indicate that the intensity of Nicholas has remained steady over the past several hours despite having moved a little farther inland over the upper Texas coastal plain. Both satellite and radar data also indicate that the overall circulation has tightened up somewhat, although a large swath of stable low clouds have advected into most of the southern semicircle of Nicholas' circulation. The highest sustained wind speeds of 34-36 kt have occurred in a narrow band of fragmented, shallow convection between Sabine Pass, Texas, and Cameron, Louisiana, during the past couple of hours. Doppler radar velocity data from Lake Charles has also indicated wind speeds of 40-45 at 3,000 ft altitude just offshore the southwestern coast of Louisiana. Based on these wind data, the initial intensity is set at 35 kt. The estimated central pressure of 1003 mb is based on nearby surface observations, especially the reports from the Eagle Point, Texas, C-MAN station, which indicate that the center of Nicholas passed over or near that station between 1800-1900 UTC. As Nicholas moves farther inland, gradual weakening is forecast due to land interaction, entrainment of drier and more stable low- and mid-level air, and strong westerly vertical wind shear in excess of 30 kt. Nicholas is forecast to become a tropical depression later this evening and degenerate into a remnant low by late Wednesday or early Thursday.

The initial motion estimate is east-northeastward or 070 degrees at 5 kt. Nicholas is forecast by most of the global and regional models continue its east-east-northeastward motion through tonight, followed by an eastward motion at a slower forward speed on Wednesday and Thursday. Nicholas could still stall over southwestern or central Louisiana as the low-level steering flow collapses on Thursday. The new NHC track forecast is similar to the previous advisory track, and lies near the consensus track models TCVA and NOAA-HCCA.

Although the winds associated with Nicholas will gradually subside, heavy rainfall and a significant flash flood risk will continue along the Gulf Coast for the next couple of days.