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.
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
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.
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
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/09/030938_5day_cone_no_line_and_wind.png?fit=897%2C736&ssl=1736897adminadmin2021-09-13 23:37:452021-09-14 00:10:27Nicholas, Now a Hurricane, Expected to Slow to a Crawl Near SW Louisiana
The 10 AM update from the National Hurricane Center shows that the eye of Nicholas is reforming yet again – further east from where it first reformed earlier today near Brownsville. This means that the cone of uncertainty for Nicholas has expanded. It now includes the entire Houston Area. And although chances of a hurricane are low, the hurricane watch has been extended northward to San Luis Pass.
Nicholas’ Cone Now Includes All of Houston
Remember that every place within the cone has an equal change of having the storm pass over it.
Main Threats from Tonight to Tomorrow Night
Bands of heavy rainfall and gusty winds continue to spread inland from the coast and will increase in frequency and intensity this afternoon into tonight. Core of Nicholas will move across southeast Texas….especially areas south of I-10 overnight into Tuesday with significant rainfall likely.
Harris County Meteorologist Jeff Lindner warns that while Nicholas is not forecasted to become a hurricane, it is possible that it could landfall as a minimal hurricane….but this does NOT change the impacts.
Impact Predictions Remain Unchanged Since Last Update
Significant rains will begin early this evening and likely continue into Tuesday morning.
Rainfall rates of 2-4 inches per hour will be possible yielding rapid street flooding and significant rises on bayous and creeks.
Lindner’s main concern is watersheds south of I-10 (Clear Creek, Armand Bayou, Vince and Little Vince Bayous, Keegans Bayou, and possibly Brays Bayou). However, Lindner still sees risk north I-10.
Some bayous and creeks may overflow their banks. Structure flooding is possible tonight. The majority of the rainfall is going to be tonight into Tuesday morning.
Residents should stay where they are after 6:00 PM this evening and remain there through the duration of Nicholas.
According to Harris County meteorologist Jeff Lindner, “The center of Nicholas has reformed overnight about 150 miles to the northwest of the previous center or just off the tip of the northeast Mexican coast. With the center reformation, the track timing has been moved up by about 12 hours.”
NOAA Satellite image taken at 7:06 am Houston time this morning.
Infrared image taken at 8:16 am Houston time this morning. Infrared imagery is useful for determining thunderstorm intensity. Strong to severe thunderstorms will normally have very cold tops.
Nicholas will now make landfall along the middle Texas coast later this afternoon or this evening.
National Hurricane Center
Said Lindner, “The center is now clearly defined on Brownsville radar and has been sampled by a USAF mission. The latest mission has found that the central pressure is starting to fall and is down to 1001 mb. Maximum sustained winds now reach 60mph. A large mass of very deep convection now extends several hundred miles into the Gulf of Mexico. Nicholas is moving toward the NNW around 14mph and will pass just offshore of Brownsville this morning. This will be a significant rainfall event for southeast Texas.”
Watches and Warnings Now in Effect
A Tropical Storm Warning is in effect for…
Mouth of the Rio Grande to High Island Texas
Barra el Mezquital to the U.S./Mexico border
A Tropical Storm Watch is in effect for…
East of High Island Texas to Sabine Pass
A Hurricane Watch is in effect for…
Port Aransas to Freeport Texas
Flash Flood Watch is in effect for:
Areas along and SE of US 59
A Storm Surge Warning is in effect for…
Port Aransas to San Luis Pass Texas
Aransas Bay, San Antonio Bay, and Matagorda Bay
Storm Surge Watch is in effect for…
Mouth of the Rio Grande to Port Aransas Texas
San Luis Pass Texas to Rutherford Beach Louisiana, including Galveston Bay
Baffin Bay and Corpus Christi Bay
Track
Forecasters predict a general northward motion toward the Matagorda Bay area followed by a gradual turn toward the NNE and NE. The forward motion of Nicholas will slow after moving inland over the TX coast.
Predicted track as of 7 am Houston time this morning. The storm should pass closest to Houston around mid-day tomorrow, but as a tropical depression. Note: the cone only indicates the potential path of the storm center, not the storm’s width, which can be much wider.
Intensity
Radar shows the Nicholas is attempting to form an inner core. However, moderate wind shear and dry air reaching into the center have slowed this process. With that said, Nicholas is now moving over very warm waters. Lindner predicts the shear may weaken over the next 8-10 hours. That may let Nicholas intensify close to hurricane strength at landfall. Nicholas should make landfall as a strong tropical storm or minimal hurricane.
Tropical storm force winds currently extend outward 115 miles…mainly to the east of the center.
NHC gives most of the Houston area a 30-60% chance of experiencing tropical-storm-force winds.
Impacts
Rainfall:
Significant rainfall is expected along and east of the track of Nicholas. This rainfall may produce areas of considerable flash and urban flooding, especially in highly urbanized metropolitan areas. Additionally, there is the potential for isolated minor to moderate river flooding.
While rainfall totals are indicated over the 5 -7 day period, much of the rainfall is expected to fall over a 2-3 day period starting later tonight.
Coastal counties: widespread 10-15 inches (isolated totals up to 20 inches)
South/East of US 59: widespread 8-12 inches (isolated totals up to 15 inches)
North of I-10: widespread 4-6 inches (isolated totals up to 8 inches)
After landfall, models do not aon how quickly the tropical cyclone will move northeastward out of Texas. The forward speed is important to the heavy rainfall forecast, and this trend will be one to watch.
The usually conservative Space City Weather team warns that the flood threat in this event may compare to Tropical Storm Imelda and the 2016 Memorial Day weekend.
Rainfall will generally be heaviest near the coast with diminishing amounts as you move inland. However, training bands could create much higher than predicted totals in northern areas.
Water vapor satellite image captured at 8:21 Houston time this morning.
The National Weather Service’s Weather Prediction Center gives most of the Houston area a moderate risk of flash flooding, but some areas near the coast will have a high risk.
Winds:
Tropical storm force winds are likely along the coast from Matagorda to Galveston Bay and inland to the US 59 corridor. Sustained winds in the 65-75mph range will be possible over the Matagorda Bay region northward into Jackson and possibly southern Wharton Counties with sustained tropical storm force winds spreading inland into portions of Harris, Fort Bend, and Colorado Counties.
Tropical-storm-force winds could arrive in the Houston area later this afternoon.
Maximum sustained winds are currently near 60 mph (95 km/h) with higher gusts. Strengthening is forecast today, and Nicholas could reach the northwest Gulf coast as a hurricane. Weakening is anticipated on Tuesday and Wednesday while Nicholas moves over land.
Tropical-storm-force winds extend outward up to 115 miles (185 km) from the center. South Padre Island recently reported a wind gust to 45 mph.
Tropical storm conditions are expected to first reach southern Texas this morning, making outside preparations difficult or dangerous. These conditions will spread northward within the warning area through tonight. Hurricane conditions are possible in the Hurricane Watch area as early as this afternoon. Tropical storm conditions are possible within the watch area by tonight or early Tuesday.
Tides:
Expect storm surge of 3-5 feet from Port O Connor to Sargent and 2-4 feet from Sargent to High Island above normal dry ground. Some significant inundation is possible around Matagorda Bay. Additionally, waves on top of the surge will result in significant beach erosion and wave run-up.
Areas NE of Galveston Bay could experience 2-4 feet of storm surge, while areas SW could experience 3-5.
Gradual Weakening Predicted
Nicholas should weaken after landfall, diminish into a tropical depression within a couple of days, and degenerate into a remnant low in about 3 days.
Key Messages
Heavy rainfall will impact portions of the Texas and Louisiana coasts through the middle of the week. Significant rainfall amounts are possible, potentially resulting in areas of considerable flash and urban flooding, especially in highly urbanized metropolitan areas. Isolated minor to moderate river flooding is also expected.
There is the danger of life-threatening storm surge inundation along the coast of Texas from Port Aransas to San Luis Pass. Residents in these areas should follow any advice given by local officials.
Nicholas is forecast to approach the middle Texas coast as a strong tropical storm today, and could be near hurricane intensity at landfall. Tropical storm conditions are expected along portions of the middle Texas coast beginning by this afternoon, with hurricane conditions possible from Port Aransas to Freeport this afternoon and tonight.
Tropical storm conditions are expected along portions of the northeastern coast of Mexico and the coast of south Texas beginning during the next few hours.
Posted by Bob Rehak on 9/13/2021 at 8AM based on information from HCFCD and NHC
1476 Days since Hurricane Harvey
00adminadmin2021-09-13 08:46:112021-09-13 08:56:24Eye of Nicholas Reforms, Timetable Moved Up
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.”
The current 10 PM official forecast shows Nicholas moving more slowly than the previous forecast.
Key Messages
Wind Force Probabilities Increasing
Rain Forecast Less Extreme in North Houston Area
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
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.
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
Cone of Nicholas Shifts East, Now Includes Houston, Hurricane Watch Expanded
The 10 AM update from the National Hurricane Center shows that the eye of Nicholas is reforming yet again – further east from where it first reformed earlier today near Brownsville. This means that the cone of uncertainty for Nicholas has expanded. It now includes the entire Houston Area. And although chances of a hurricane are low, the hurricane watch has been extended northward to San Luis Pass.
Nicholas’ Cone Now Includes All of Houston
Main Threats from Tonight to Tomorrow Night
Bands of heavy rainfall and gusty winds continue to spread inland from the coast and will increase in frequency and intensity this afternoon into tonight. Core of Nicholas will move across southeast Texas….especially areas south of I-10 overnight into Tuesday with significant rainfall likely.
Harris County Meteorologist Jeff Lindner warns that while Nicholas is not forecasted to become a hurricane, it is possible that it could landfall as a minimal hurricane….but this does NOT change the impacts.
Impact Predictions Remain Unchanged Since Last Update
Rainfall, wind, and storm surge impacts remain unchanged from my post earlier this morning.
Significant rains will begin early this evening and likely continue into Tuesday morning.
Rainfall rates of 2-4 inches per hour will be possible yielding rapid street flooding and significant rises on bayous and creeks.
Lindner’s main concern is watersheds south of I-10 (Clear Creek, Armand Bayou, Vince and Little Vince Bayous, Keegans Bayou, and possibly Brays Bayou). However, Lindner still sees risk north I-10.
Some bayous and creeks may overflow their banks. Structure flooding is possible tonight. The majority of the rainfall is going to be tonight into Tuesday morning.
Best Ways to Monitor Nicholas
Closely monitor bayou and creek conditions and rainfall trends. The best way to do that is through the Harris County Flood Warning System.
Also, closely monitor the National Hurricane Center website. This page contains their latest satellite image updates. During storms like this, they update them hourly. Here’s one from 11:46 AM Houston time.
Posted by Bob Rehak on 9/13/2021 at 10:30 AM and again at Noon
1476 Days since Hurricane Harvey
Eye of Nicholas Reforms, Timetable Moved Up
8am CDT, 9/13/2021
According to Harris County meteorologist Jeff Lindner, “The center of Nicholas has reformed overnight about 150 miles to the northwest of the previous center or just off the tip of the northeast Mexican coast. With the center reformation, the track timing has been moved up by about 12 hours.”
Said Lindner, “The center is now clearly defined on Brownsville radar and has been sampled by a USAF mission. The latest mission has found that the central pressure is starting to fall and is down to 1001 mb. Maximum sustained winds now reach 60mph. A large mass of very deep convection now extends several hundred miles into the Gulf of Mexico. Nicholas is moving toward the NNW around 14mph and will pass just offshore of Brownsville this morning. This will be a significant rainfall event for southeast Texas.”
Watches and Warnings Now in Effect
Track
Forecasters predict a general northward motion toward the Matagorda Bay area followed by a gradual turn toward the NNE and NE. The forward motion of Nicholas will slow after moving inland over the TX coast.
Intensity
Radar shows the Nicholas is attempting to form an inner core. However, moderate wind shear and dry air reaching into the center have slowed this process. With that said, Nicholas is now moving over very warm waters. Lindner predicts the shear may weaken over the next 8-10 hours. That may let Nicholas intensify close to hurricane strength at landfall. Nicholas should make landfall as a strong tropical storm or minimal hurricane.
Tropical storm force winds currently extend outward 115 miles…mainly to the east of the center.
Impacts
Rainfall:
Significant rainfall is expected along and east of the track of Nicholas. This rainfall may produce areas of considerable flash and urban flooding, especially in highly urbanized metropolitan areas. Additionally, there is the potential for isolated minor to moderate river flooding.
While rainfall totals are indicated over the 5 -7 day period, much of the rainfall is expected to fall over a 2-3 day period starting later tonight.
After landfall, models do not aon how quickly the tropical cyclone will move northeastward out of Texas. The forward speed is important to the heavy rainfall forecast, and this trend will be one to watch.
The usually conservative Space City Weather team warns that the flood threat in this event may compare to Tropical Storm Imelda and the 2016 Memorial Day weekend.
Winds:
Tropical storm force winds are likely along the coast from Matagorda to Galveston Bay and inland to the US 59 corridor. Sustained winds in the 65-75mph range will be possible over the Matagorda Bay region northward into Jackson and possibly southern Wharton Counties with sustained tropical storm force winds spreading inland into portions of Harris, Fort Bend, and Colorado Counties.
Maximum sustained winds are currently near 60 mph (95 km/h) with higher gusts. Strengthening is forecast today, and Nicholas could reach the northwest Gulf coast as a hurricane. Weakening is anticipated on Tuesday and Wednesday while Nicholas moves over land.
Tropical-storm-force winds extend outward up to 115 miles (185 km) from the center. South Padre Island recently reported a wind gust to 45 mph.
Tropical storm conditions are expected to first reach southern Texas this morning, making outside preparations difficult or dangerous. These conditions will spread northward within the warning area through tonight. Hurricane conditions are possible in the Hurricane Watch area as early as this afternoon. Tropical storm conditions are possible within the watch area by tonight or early Tuesday.
Tides:
Expect storm surge of 3-5 feet from Port O Connor to Sargent and 2-4 feet from Sargent to High Island above normal dry ground. Some significant inundation is possible around Matagorda Bay. Additionally, waves on top of the surge will result in significant beach erosion and wave run-up.
Gradual Weakening Predicted
Nicholas should weaken after landfall, diminish into a tropical depression within a couple of days, and degenerate into a remnant low in about 3 days.
Key Messages
Posted by Bob Rehak on 9/13/2021 at 8AM based on information from HCFCD and NHC
1476 Days since Hurricane Harvey