Beta Rainfall Estimates Increasing; 6-10 Inches Now Predicted for Lake Houston Area
Beta has turned toward the Texas coast. Adverse conditions will likely begin Sunday along coast and spread inland. The main forecast change since this morning? An increase in rainfall amounts, which could be significant. See rainfall section below.
A Flash Flood Watch will likely be issued on Sunday for the area.
Jeff Lindner, Harris County Meteorologist
Discussion
There has been little change in the overall organization of Beta today. Forecasters expect slow intensification as Beta approaches the TX coast.
Track:
There have been no significant changes in the track reasoning today and the official forecast remains similar from earlier this morning. With that said, there is some uncertainty on when Beta will turn toward the N and NE near the mid Tx coast early next week, but generally impacts will be the same for much of SE TX.
Intensity:
Given the lack of organization of the system and the lurking dry air to the west, it is now unlikely that Beta will attain hurricane intensity. The National Hurricane Center now keeps the system as a strong tropical storm as it approaches the TX coast. It should slowly as it moves NE or ENE up the coast.
Impacts
Storm Surge:
Water levels will rise along the upper TX coast beginning Saturday and worsen Sunday into Monday due to the expansion of the tropical storm force wind field. Expect swells reaching 15-25 feet over the NW Gulf. Four- to eight-foot waves could break on beaches. These large swells will lead to wave run up on top of the elevated tides.
Results:
- Significant beach erosion
- Damage to fragile dune systems.
- Damage to coastal infrastructure
- Inundation of low lying roads near the coast.
- Once the water begins to rise on Saturday evening, some low lying areas may remain flooded into the middle of next week.
- Overwash is likely on Hwy 87.
- Ferry operations at both the Galveston-Bolivar and the Lynchburg sites may be impacted.
Rainfall:
While there is still some uncertainty, the storm could produce very heavy rainfall rates and amounts.
Jeff Lindner, Harris County Meteorologist
The rainfall forecasts have been adjusted upward, even though some models suggest only meager amounts of rainfall with Beta. Jeff Lindner, Harris County Meteorologist, currently predicts:
- Coast: 12-18 inches
- Coastal counties: 10-15 inches
- South of I-10: 10-15 inches
- South of Hwy 105: 6-10 inches
- North of Hwy 105: 4-6 inches
Given the forecast rainfall amounts…flooding of creeks and bayous across Harris County may flood depending on how the rain falls and how much falls at one time.
Six inches could fill smaller creeks; 7-8 inches could fill larger streams and bayous such as Buffalo.
Addicks and Barker Reservoirs are currently empty.
Winds:
Tropical storm force winds will be possible starting Sunday evening around Matagorda Bay with sustained 40mph winds likely spreading northward along the upper TX coast on Monday including Galveston Bay. Sustained winds of 55-65mph will spread up the TX coast Tuesday into Wednesday. Across Harris County wind will increase into the 25-35mph range on Monday and possibly 40-45mph range on Tuesday into Wednesday with higher gusts, especially near Galveston Bay.
Note: Tropical storm force winds will begin to reach the coast on Monday…well ahead of any landfall of the center…due to the expanding wind field. Tropical storm force winds now extend 175 miles outward from the center of the storm.
Summary of Watches/Warnings In Effect
A STORM SURGE WARNING IS IN EFFECT FOR
- PORT ARANSAS TEXAS TO HIGH ISLAND TEXAS INCLUDING:
- COPANO BAY
- ARANSAS BAY
- SAN ANTONIO BAY
- MATAGORDA BAY
- GALVESTON BAY
A STORM SURGE WATCH IS IN EFFECT FOR:
- * BAFFIN BAY TEXAS TO PORT ARANSAS TEXAS INCLUDING BAFFIN BAY AND CORPUS CHRISTI BAY
- * HIGH ISLAND TEXAS TO CAMERON LOUISIANA INCLUDING SABINE LAKE AND LAKE CALCASIEU
A HURRICANE WATCH IS IN EFFECT FOR:
* PORT ARANSAS TEXAS TO HIGH ISLAND TEXAS
A TROPICAL STORM WARNING IS IN EFFECT FOR:
- PORT ARANSAS TEXAS TO INTRACOASTAL CITY LOUISIANA
A TROPICAL STORM WATCH IS IN EFFECT FOR:
- SOUTH OF PORT ARANSAS TEXAS TO THE MOUTH OF THE RIO GRANDE
- EAST OF INTRACOASTAL CITY LOUISIANA TO MORGAN CITY LOUISIANA
Protective Actions
- Bookmark and monitor Harris County Flood Warning System throughout the storm. Familiarize yourself with the real-time inundation mapping feature.
- Bookmark and monitor the National Hurricane Center for the most current updates on Beta.
- Prepare now for a long period of coastal flooding and periods of heavy rainfall.
- Voluntary evacuations have been recommended for:
- Western end of Galveston Island, west of the seawall
- Bolivar Peninsula
- Low-lying areas of Chamber, Brazoria and Matagorda Counties (outside levee protection)
- Low-lying areas of Seabrook.
AlertHouston Recommends Taking These Steps Now
- Ensure your family has 5-7 days of food, water, and necessary supplies.
- This includes enough prescription medication for at least this duration, in case pharmacies and doctor’s offices are closed.
- Consider the unique needs of small children, seniors, family members with access and functional needs, and pets.
- Decide what you and your family will do if the storm impacts your area. Most City of Houston residents are not vulnerable to storm surge and do not need to evacuate before a hurricane or tropical storm. Vulnerable residents who require electricity may also consider evacuation in advance of a major storm. For a map of hurricane evacuation zones and mandatory evacuation areas, visit: houstonoem.org/hurricanes
- Develop a family communication plan, so that you know who to check in with after a storm. Visit readyhoustontx.gov for more information on developing a plan.
- Know how to turn off your utilities. This includes electricity, water, and gas. Only turn off gas if instructed by local officials or by CenterPoint Energy.
Posted by Bob Rehak on 9/19/2020 with data from the NHC, HCFCD, and City of Houston
1117 Days since Hurricane Harvey and 1 Year since Imelda
