1. Heavy rainfall will impact areas from the upper coast of Texas, across Louisiana, southern Mississippi, far southern Alabama and the western Florida Panhandle through Thursday. Significant rainfall amounts are expected, potentially resulting in areas of life-threatening flash and urban flooding across these areas. Minor to isolated major river flooding is also possible in smaller river basins and urban areas.

2. There is the danger of life-threatening storm surge inundation along the coast of Texas from Port Bolivar to Sabine Pass. Residents in these areas should follow any advice given by local officials.

3. Tropical storm conditions are expected to continue along the Louisiana coast into this afternoon. Tropical storm conditions in the warning area across the upper Texas coast will diminish this afternoon as Nicholas moves farther to the northeast.

CHANGES WITH THIS ADVISORY:

The Storm Surge Warning has been discontinued west of High Island including Galveston Bay.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
- High Island Texas to Sabine Pass

A Tropical Storm Warning is in effect for...
- High Island Texas to Cameron Louisiana

A Storm Surge Watch is in effect for...
- Sabine Pass to Cameron Louisiana

A Storm Surge Warning means there is a danger of lifethreatening inundation, from rising water moving inland from the coastline. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a lifethreatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials.

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area.

A Storm Surge Watch means there is a possibility of lifethreatening inundation, from rising water moving inland from the coastline. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov.

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 of 5 to 10 inches from the upper Texas coastal area into central to southern Louisiana, far southern Mississippi, far southern Alabama and the western Florida Panhandle through Thursday, with isolated storm totals of 20 inches across southern Louisiana. Lifethreatening flash flooding impacts, especially in urbanized metropolitan areas, are possible across these regions.

Widespread minor to isolated major 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 Hurricane 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 dangerous 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...

High Island, TX to Cameron, LA...24 ft San Luis Pass to High Island, TX...13 ft Galveston Bay...13 ft Cameron, LA to Intracoastal City, LA...13 ft Sabine Lake and Calcasieu Lake...13 ft The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and dangerous waves. Surgerelated flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. 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 coast into this afternoon. Tropical storm conditions in the warning area across the upper Texas coast will diminish this afternoon as Nicholas moves farther to the east.

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

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

At 100 PM CDT (1800 UTC), the center of Tropical Storm Nicholas was located near latitude 29.4 North, longitude 95.0 West. Nicholas is moving toward the eastnortheast near 7 mph (11 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 have decreased to near 40 mph (65 km/h) with higher gusts. Additional weakening is forecast during the next couple of days, and the storm is forecast to become a tropical depression by tonight.

Tropicalstormforce winds extend outward up to 140 miles (220 km), mainly over water to the southeast of the center. A TCOON observing station at Texas Point, Sabine Pass, Texas, recently measured a 1minute sustained wind of 40 mph (65 km/h) and a gust to 53 mph (85 km/h) while a NOAA Ocean Service observing station at Calcasieu Pass, Louisiana, recently reported a 1minute sustained wind of 39 mph (63 km/h) and a gust to 47 mph (76 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 Nicholas has continued to weaken while moving farther inland. The strongest winds recently reported near the Texas and Louisiana coasts have been 33-35 kt at a TCOON observing station near Sabine Pass, Texas. The strongest winds over water south of southwestern Louisiana are based on Doppler radar average velocities of 45-50 kt between 5000-7500 ft. Based on these wind data, the initial intensity has been lowered to 40 kt. The estimated central pressure of 1002 mb is based on nearby surface observations in the Houston metropolitan area. Further weakening is expected as Nicholas moves farther inland due to frictional effects, entrainment of very dry mid-level air from the southern Plains, and increasing southwesterly to westerly shear. The latter condition is expected to cause the low- and upper-level circulation to decouple in about 24 hours, which will hasten the weakening process. No significant changes were made to the previous intensity forecast, and Nicholas is now expected to become a tropical depression by tonight and degenerate into a remnant low by late Wednesday.

Nicholas is now moving northeastward or 050 degrees at a slower forward speed of 5 kt. The cyclone should gradually turn toward the east-northeast by tonight, and move eastward more slowly on Wednesday and Thursday. It is possible that Nicholas could stall over southwestern or central Louisiana as the low-level steering flow collapses. The new NHC track forecast is similar to but slightly slower than the previous advisory tack.

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