Tag Archive for: National Hurricane Center

NHC Predicts Christobal to Hit Louisiana by Sunday Morning, Houston Still Within Cone

Cristobal should approach the northern Gulf coast within 4 days. The latest predictions from the National Hurricane Center (NHC) suggest it should reach Louisiana Sunday morning by 8 a.m. Houston remains within the cone of uncertainty. The storm has already dumped torrential rains on Mexico and Central America and produced life-threatening flash flooding.

NHC forecast track of TS Christobal shows the center of the storm arriving in Louisiana sometime between Sunday and Monday.

No one is yet predicting the exact point of impact, the intensity at landfall, or the potential rainfall. Note, however, that the storm is significantly bigger than the center. Areas far away from the track may still experience significant impacts.

So far, this storm appears to be Mexico’s and Central America’s version of Harvey in that it has stalled in one location and dropped heavy rainfall for 4-5 days.

Current Location and Conditions

Here’s what’s happening at this hour.

Cristobal dipped inland this morning in the Mexican State of Campeche around around 8 a.m. CDT. Aircraft and surface reports indicate intensity at about 50 kt. (57.5 mph).

Now that the center of circulation has moved inland, a gradual weakening trend should commence. The NHC anticipates Cristobal will weaken to a topical depression by tomorrow evening. However, they also predict the system will re-emerge into the Gulf of Mexico.

Sheer Expected in Northern Gulf

NHC says global models show increased southwesterly shear influencing the cyclone over the northern Gulf of Mexico and this should limit intensification. However, there is significant uncertainty as to how strong a cyclone we will be dealing with near the northern Gulf coast this weekend.

Impacts to Date

Damaging and deadly flooding has occurred in portions of Mexico and Central America. Cristobal is expected to produce additional extreme rainfall amounts through the end of the week. The heaviest additional rainfall is expected over far southern Mexico and portions of the Yucatan Peninsula, while also extending along the Pacific coast from Chiapas to Guatemala and El Salvador. This rainfall could cause widespread life-threatening flash floods and mudslides. Up to 35 inches of rain has already fallen in some locations since May 30.

Even though Cristobal has made landfall, tropical storm conditions will continue along and near the coast of Mexico through Thursday, especially over western Campeche, eastern Tabasco, and northern Chiapas states.

Rainfall in Mexico and Central America Through Friday

NHC predicts Cristobal will produce the following rain accumulations through Friday night:

  • Mexican states of Campeche, northern Chiapas, Quintana Roo, Tabasco, and Yucatan…10 to 20 inches, isolated 25 inches.
  • Mexican state of southern Chiapas…15 to 20 inches, isolated 25 inches. Mexican states of Veracruz and Oaxaca…5 to 10 inches.
  • Southern Guatemala…Additional 15 to 20 inches, isolated storm total amounts of 35 inches dating back to Saturday, May 30th.
  • El Salvador…Additional 10 to 15 inches, isolated storm total amounts of 35 inches dating back to Saturday, May 30th.
  • Belize and Honduras…3 to 6 inches, isolated 10 inches.
  • Rainfall in all of these areas may produce life-threatening flash floods and mudslides.

Threat to U.S. by Sunday

NHC forecasts Cristobal to re-emerge over the southern Gulf of Mexico Friday or Friday night.

Christobal should then move northward over the central and northern Gulf over the weekend. Risks to the US Gulf coast from Texas to the Florida Panhandle include storm surge, heavy rainfall, and wind impacts beginning this weekend.

While it is too soon to determine the exact location, timing, and magnitude of these impacts, people and businesses in these areas should monitor the progress of Cristobal and ensure they have their hurricane plan in place.

Earliest Arrival Times of Tropical Storm Force Winds. NHC prediction as of 6/3/2020 at 10AM CDT.

Posted by Bob Rehak on 6/3/2020 at 11:30 a.m.

1009 days after Hurricane Harvey

NHC Upgrades Chances of Topical System Formation in Gulf to 80%

Update: This post was created at 10 a.m. As of 1 p.m. the National Hurricane Center upgraded the chances of tropical development another 10% to 90%.

Pacific Tropical Storm Amanda moved into Central America and southern Mexico last weekend. It is now poised to re-emerge into the Gulf of Mexico and may form another tropical system. Since yesterday morning, the National Hurricane Center (NHC) upgraded the chances of formation within the next two days from 40% to 80%. The NHC also upgraded chances of formation within five days from 50% to 80%.

Remnants of Pacific Tropical Storm Amanda over the Yucatan and Central America. Source: NOAA. Motion is toward the northwest.
Source: NOAA National Hurricane Center. As of 7am 6/1/2020.

Will Likely Move into Bay of Campeche

NHC expects this large area of disturbed weather to move northwestward over the southeastern portion of the Bay of Campeche later today or tonight. Environmental conditions there are expected to be conducive to support development.

A new tropical depression is likely to form within within the next day or so.

National Hurricane Center

The system is moving around the northern side of a nearly stationary central American monsoon trough.

Conditions over the Bay of Campeche appear favorable for slow development of a surface low pressure system. Those conditions include:

  • Warm sea surface temperatures
  • Light upper level winds
  • Rising air motions
  • An envelope of tropical moisture.
Water vapor intensity and circulation. Source: University of Wisconsin Madison Space Science and Engineering Center.

Heavy Rainfall for Southern Neighbors For the Moment

Regardless of tropical cyclone formation, heavy rainfall should continue over portions of southern Mexico, Guatemala, El Salvador, Belize, and western Honduras during the next few days.

System Likely to Loop in Bay of Campeche Before Moving North

The tropical system will loop or remained stalled in the Bay of Campeche (the bay between the Yucatan and Mexican mainland) for the next 2-4 days. After that, most models take it toward the US Gulf coast, but there is little agreement among the models at this early stage of formation. Currently, they indicate landfall anywhere between Mexico and Florida. We should have a better indication of the track toward the middle of this week.

Official Start of Hurricane Season Today

Today marks the first day of the Atlantic hurricane season, which will run until November 30. The list of names for 2020 follows:

Two tropical storms, Arthur and Bertha, already formed this year in May. The next named storm that develops this season will be Cristobal.

The NHC monitors significant areas of disturbed weather and their potential for tropical cyclone formation. NHC updates forecasts at 1 AM, 7 AM, 1 AM, and 7 PM CDT.

What You

Harris County Flood Control meteorologist Jeff Lindner advises residents along the US Gulf coast to closely monitor the progress of this system. “Now is a very good time to review plans and fully stock preparation kits,” he says.

Posted by Bob Rehak on 6/1/2020 at 10am with thanks to NHC, HCFCD and Univ. of Wisconsin

1006 Days after Hurricane Harvey

NHC Gives 40-50% Chance of Tropical Cyclone Formation In Gulf This Week

NHC Special Tropical Weather Outlook NWS National Hurricane Center Miami FL 805 AM EDT Sun May 31 2020 For North Atlantic, Caribbean Sea and Gulf of Mexico:

Source: National Hurricane Center 5 Day Tropical Outlook for Atlantic as of 7:05AM CDT on 5/31/2020

The National Hurricane Center (NHC) forecasts the Eastern Pacific Tropical Storm Amanda, now centered inland over southeastern Guatemala, to weaken into a remnant low or dissipate over Guatemala or southeastern Mexico by tonight.

However, the NHC also predicts that the remnants of Amanda will move northwestward within a broader area of disturbed weather, possibly emerging over the southeastern Bay of Campeche on Monday.

If the remnants move back over water, environmental conditions appear conducive to support some redevelopment of the system while it moves little through the middle of this week.

Regardless of redevelopment, heavy rainfall is likely to continue over portions of southern Mexico during the next few days. For additional information on the rainfall threat, see products from your national meteorological service.

The next Special Tropical Weather Outlook will be by 3 PM EDT today, or earlier if necessary.

  • Formation chance through 48 hours…medium…40 percent.
  • Formation chance through 5 days…medium…50 percent.

 If it does become a named storm, it would be Cristobal.

Tropical Storm Amanda will likely cross into the Gulf of Mexico on Monday. (Source: NOAA via Space City Weather).

Too Early to Predict Direction of Storm

Jeff Lindner, Harris County Flood Control District meteorologist, says, “Where exactly any center forms will determine what sort of longer term track would be possible … across the Gulf of Mexico.”

“Regardless of development,” he continues, “a large plume of tropical moisture will be moving into the SW and eventually the western Gulf of Mexico this week. Some of this moisture will likely get directed toward the Texas coast by late week and next weekend.”

“As with any tropical system in this stage of potential development, there is lots of uncertainty.”

“The best course of action is to monitor weather forecasts daily and National Hurricane Center outlooks for any changes.”

Jeff Lindner, Harris County Flood Control meteorologist

Preparedness

Hurricane season starts tomorrow. The NHC predicts above-average activity this hurricane season.

Source: National Hurricane Center prediction on 5/21/2020.

Now would be a good time to prepare. The major risks in the Lake Houston area include river and street flooding (as we saw with Harvey, Allison and Imelda) and wind damage (as we saw with Ike). Ike led to prolonged power outages due to trees falling against power lines.

Make sure you have fresh batteries and a backup supply, as well as a weather radio.

Also make sure you have a way to charge your cell phone (vehicle or power block). And make sure you learn how to use the Harris County Flood Warning System to increase your situational awareness.

Familiarize yourself with the LINKS page of this website. It contains links to many useful sites specializing in preparedness and weather.

Remember: the COVID crisis presents an extra layer of complication this year.

Lake Level Report

As of this morning, the level of Lake Conroe was 200.23 feet and the SJRA continues releasing 1581 cubic feet per second. Their goal: to bring the lake down to 200 feet by tomorrow.

Also as of this morning, the Coastal Water Authority indicates that the level of Lake Houston is down approximately one foot.

Lake Level41.46 ft.
Normal Pool42.4 ft.
Source: Coastal Water Authority readings as of 7:30am 5/31/2020.

Posted by Bob Rehak on 5/31/2020

1006 Days after Hurricane Harvey

Tropical Cyclone Threat Increases Later This Week

The National Hurricane Center and Harris County meteorologist Jeff Lindner now predict that a tropical cyclone will likely develop in the Gulf of Mexico later this week.

5-day outlook shows low pressure system tracking westward over warm Gulf waters.

Models Now Predict Westward Development

Overnight, the threat increased westward along the Louisiana and Texas coasts.

The National Weather Service expects a trough of low pressure located over central Georgia to move southward toward the northeastern Gulf of Mexico. There, it should form a broader area of low pressure in a couple of days. A tropical depression will likely form by the end of the week while the low meanders near the northern Gulf Coast.

Regardless of development, this system has the potential to produce heavy rainfall along portions of the northern and eastern U.S. Gulf Coast later this week. Formation chance in the next two days remains low at 10 percent, but increases to 80 percent in the 5-day outlook.

Likely Path

Upper air conditions appear favorable for a tropical system to form and then intensify over much of the US Gulf coast and northern Gulf. Models now predict that any Gulf system would tend to track more westward.

Intensity

“A tropical storm is likely and a hurricane is not out of the question,” says Lindner. “If forecast models continue to show the westward motion and potential threat to the northwest Gulf, significant forecast changes will be required over the next 24-48 hours.” 

What to Do Now

  • Closely monitor the progress of this system.
  • Check hurricane preparation kits and plans.
  • Be ready to enact those plans later this week.
  • Monitor weather forecasts closely.   

Posted by Bob Rehak on 7/8/2019

678 Days since Hurricane Harvey

Conditions in Atlantic Becoming More Favorable for Tropical Development

I just received an email from Jeff Lindner, Director of Hydrologic Operations Division/Meteorologist for Harris County Flood Control District about a potential tropical development.

Linder says, “There has been little mention of the Atlantic tropics thus far this hurricane season…even though we are already on our “E” storm. Most of the storms have been focused in the sub-tropical north Atlantic away from the generally hostile conditions in the deep tropics and far removed from any land interaction.”

National Hurricane Center Five Day Graphical Tropical Weather Outlook gives this tropical disturbance a 20% chance of tropical formation over the next five days.

Conditions in Tropics Becoming More Favorable for Tropical Development

“However conditions are starting to slowly change and as is usual for mid-August, conditions are becoming more favorable for tropical development in the deep tropics or that region between Africa and the Caribbean Sea,” said Lindner.

Tropical Wave 99L

Lindner continued: “A tropical wave roughly 850 miles east of the southern Windward Islands has shown an increase in deep convection today. This convection (thunderstorms) remains fairly disorganized at this time. Significant amounts of Saharan Air (dusty air from the deserts of N Africa) have been generally keeping the formation of convection to a minimum for the last 2 months, but 99L has found itself far to the south (near 8N) and mainly south of the dusty air across the mid Atlantic. This system has also found itself near/under a building ridge of high pressure aloft and removed from the anomalous strong wind shear thus far this year across the Caribbean Sea and Atlantic.”

“Conditions appear at least marginally favorable for some slow development of this feature as it moves W to WNW over the next 48-72 hours.”

“There is little to no model support for this feature to develop, but we shall see what the 00Z and 12Z models suggest. At the 800pm this evening, the Hurricane Center is giving this system a 20% chance of tropical development over the next 5 days as it moves generally toward the eastern Caribbean Sea.”

Lindner Cautions Against Looking Too Far into Future

“Reminder: it is important as we move into the heart of hurricane season to get information from trusted sources – especially on social media. Posts showing where a storm could be 7-9 days from now and at some level of intensity should not be believed and it is important to refrain from sharing such posts without proper context,” cautioned Lindner.

Peak of Hurricane Season is September 10

The statistical peak of hurricane season for this area is September 10, so we are still almost a month away. Nevertheless, be prepared. Check your your hurricane kit now. Don’t leave important matters for the last minute.

SJRA Still Lowering Lake Conroe

The San Jacinto River Authority (SJRA) has been steadily lowering Lake Conroe by 275 cubic feet per second to create extra capacity in the lake.  From a normal level of 201 mean feet above sea level (MSL), the goal was to reduce the lake to 199 MSL by August 15 and maintain that level until the end of September. This is to create an additional buffer against downstream flooding until the Army Corps can restore the carrying capacity of the West Fork.

However, recent rains have been refilling the lake almost as fast as the SJRA is lowering it. At the time of this post, the level was at 200.01 MSL. Visit SJRA.net to see the current level and release rate.

I am sure they will increase the discharge rate if this or any other storm approaches to get to their target of 199 MSL.

In short, nothing to worry about now. But keep your antenna up.

Posted by Bob Rehak on August 15, 2018

351 Days since Hurricane Harvey.