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 Tropical Storm Warning has been discontinued for the coasts of Texas and Louisiana.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT: There are no coastal watches or warnings in effect.

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. Lifethreatening 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 Depression 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: 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: Wind gusts to tropicalstorm force are possible this evening along the Louisiana and upper Texas coasts. These conditions should diminish tonight.

TORNADOES: A tornado or two will be possible through tonight across southern Louisiana.

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

At 700 PM CDT (0000 UTC), the center of Tropical Depression Nicholas was located by Doppler radars, satellites, and surface observations near latitude 29.9 North, longitude 94.4 West. Nicholas is moving toward the eastnortheast near 6 mph (9 km/h) and this general motion should continue through tonight. An eastward turn is expected over Louisiana on Wednesday. Little motion is anticipated on Thursday.

NOAA Doppler weather radar and surface observations indicate that maximum sustained winds have decreased to near 35 mph (55 km/h) with higher gusts. Continued gradual weakening is expected during the next couple of days, and Nicholas is forecast to degenerate into a remnant low on Wednesday or by early Thursday.

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.