Nicholas, Now a Hurricane, Expected to Slow to a Crawl Near SW Louisiana

As of its 10 PM CDT update on 9/13/2021, the National Hurricane Center (NHC) upgraded Tropical Storm Nicholas to a hurricane.

Nicholas a Minimum Cat 1 Hurricane

A weather station at Matagorda Bay reported sustained winds of 66 kt (76 mph) with a gust to 83 kt. NHC expects no additional strengthening before the system makes landfall. Gradual weakening is expected during the next 2-3 days while Nicholas moves over southeastern Texas and southwestern Louisiana.

The minimum sustained winds for a Category 1 hurricane are 74 mph.

Light Steering Currents Will Slow Nicholas

According to NHC, “Nicholas is currently moving through a weakness in a mid-level subtropical ridge. Within 12 to 24 hours, after Nicholas has moved inland, the ridge should weaken and leave Nicholas in an area of light steering currents. As a result, during the next couple of days, the cyclone should turn eastward and slow to a crawl near southwestern Louisiana.”

Nicholas should now reach the Houston Area with tropical-storm-force winds on Tuesday before slowing near the Louisiana border on Wednesday as a tropical depression..

The current 10 PM official forecast shows Nicholas moving more slowly than the previous forecast.

Key Messages

  1. Heavy rainfall will impact portions of southeastern Texas, Louisiana, and southern Mississippi through the middle of the week. Significant rainfall amounts are expected, potentially resulting in areas of life-threatening flash and urban flooding, along the eastern Texas coast into southwestern Louisiana. 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 Aransas to Sabine Pass. Residents in these areas should follow any advice given by local officials.

Wind Force Probabilities Increasing

The probability of experiencing tropical-storm-force winds in the north Houston Area is very high.

Rain Forecast Less Extreme in North Houston Area

However, the Weather Prediction Center now shows major rain accumulations only near the coast and to the east of Houston.

I already have 1.47 inches in my rain gage for today. The estimates above are for three days.

Flash Flooding Risk Now Mostly Along Coast

The risk of flash flooding mirrors the rainfall map above. The Lake Houston Area now has only a slight chance of flooding.

All in all, if the maps above are accurate, the Lake Houston Area could still see 2 to 6 inches of rain tomorrow, but that’s far better than previously predicted.

This infrared image shows the areas of heaviest rainfall as of 11:26 PM CDT 9/13/2021

Areas near the coast remain under a storm surge warning.

So far, none of the streams or bayous in Harris County have come out of their banks. To stay on top of potential local flooding on Tuesday, visit the Harris County Flood Warning System.

Posted by Bob Rehak at 11 PM Monday, 9/13/2021 based on information from NHC and HCFCD

1476 Days since Hurricane Harvey