Tag Archive for: NHC

Don Becomes First Hurricane of 2023 Atlantic Season

At 2:00 PM EDT on 7/22/23, the National Hurricane Center announced that Tropical Storm Don became Hurricane Don, the first Atlantic storm to achieve hurricane-force winds this year. Not only did Don form earlier than usual, it formed farther north than usual – between New England and Europe. Hurricanes hardly ever form in that area this early in the Atlantic hurricane season.

Hurricane Don’s Current Location

Location of Hurricane Don on is parallel with New Jersey. NOAA gives the orange area a 60% chance of formation in the next 7 days.

Hurricane Don’s Expected Track

NHC expects Don to decrease in strength to a tropical storm on Sunday and a tropical depression on Monday as it turns toward Europe.

Higher than Normal Sea Surface Temps Contribute to Early Formation

Warmer than normal sea surface temperatures played a role in the intensification of Don. Note the dark brown to black areas off the coasts of New England and Newfoundland. Those colors indicate a whopping 4 to 5 degrees centigrade above normal. That equals 7-9 degrees Fahrenheit.

No Hurricanes Reported Forming That Far North This Early

NHC shows that in the 165 years between 1851 and 2015, no other hurricane formed as far north as Don during this 10-day period.

From National Hurricane Center Climatology page.

Average Dates of Formation for Named Storms

Usually, the Atlantic Basin doesn’t see its first named hurricane until August 11. So Don is a month ahead of schedule on that count.

Dates of named storms from National Hurricane Center Climatology page.

Don is no threat to the Houston area. But Don’s timing may give us a clue to the type of hurricane season this will be. Both Colorado State and NOAA predicted slightly above average hurricane seasons this year.

The fourth tropical storm of the year doesn’t usually happen until August 15. And the first hurricane doesn’t usually happen until August 11.

El Niño Not a Factor in Don’s Formation

It takes the alignment of seven ingredients to form tropical cyclone. NOAA lists warm seas as #2. And we certainly have that around the world this year year, as you can see in the anomaly map above.

Wind shear from El Niño would not play a factor in deterring hurricane formation as far north as Don OR this early in the season, says Harris County’s meteorologist Jeff Lindner. “El Nino has little to no influence on our weather during the summer months (June-September),” says Lindner.

“The majority of El Nino’s influence on southern plains and Texas weather is during the fall, winter, and spring (October-May). This time of year we tend to be controlled by the sub-tropical highs around 30º N and/or the influences of the tropics from the Gulf of Mexico. This particular year the Sonoran sub-tropical high over the SW US and northern MX had thus far been the main controlling factor in our weather and El Nino has little impact on that.” 

Lindner concluded, “The wind shear associated with El Niño is mainly across the southern Gulf of Mexico, much of the Caribbean Sea, and the western deep tropical Atlantic. However, wind shear thus far this hurricane season has not been overly impressive for an El Nino summer and there are some suggestions that the very warm Atlantic waters may be lessening the impacts of El Nino and its wind shear in the Atlantic basin.”

We’re into uncharted territory, so to speak. This is where it gets interesting.

Posted by Bob Rehak on 7/23/2023

2155 Days since Hurricane Harvey

Necessary Ingredients for a Tropical Cyclone

This morning I visited the National Hurricane Center website to see the latest tropical developments. The Houston Area has nothing to worry about at the moment. But while I was on the NHC website, I stumbled on an incredible resource. It discussed – among other things – the necessary ingredients for a tropical cyclone. It’s called the Mariner’s Tropical Cyclone Guide, updated by Dylan Flynn in May 2023.

A Treasure Trove of Information about Tropical Systems

The title sells this electronic booklet short. It’s true that the last quarter of this 86 page booklet discusses how to navigate ships and boats near tropical cyclones. But the rest is a primer on tropical systems themselves. The booklet has four chapters:

  • Tropical Cyclone Basics
  • Climatology
  • Monitoring Tropical Cyclones
  • Tropical Cyclone Evasion

Although the book is targeted at Navy and Merchant Marine personnel, the general public will find the first three parts both informative and educational. The writing is clear, crisp, and concise. And the illustrations are illuminating. Overall, a quick read.

One of the most fascinating discussions started on page 12.

Necessary Ingredients for Development and Intensification

Flynn lists seven environmental conditions necessary for tropical cyclones to form and thrive. Eliminate one, says Flynn, and the whole system starts to break down.

  1. A pre-existing surface disturbance with thunderstorms: Tropical cyclones rely on a build-up of heat energy above them to grow and develop. A thunderstorm complex acts as a vertical transport mechanism for heat, moisture, and the cyclonic turning of winds into the upper levels of the atmosphere. This vertical transport helps tropical cyclones develop.
  2. Warm ocean: Tropical cyclones draw on the heat energy stored in the ocean. Sea surface temperatures of at least 80ºF are needed to support development and intensification. Evaporation of this warm water begins the process of energizing the atmospheric column. The warm seas should extend at least 60 m deep, as the strong winds of a tropical cyclone cause a turbulent sea that mixes the warm surface water with cooler, deeper water.
  3. Low vertical wind shear: Tropical cyclones rely on a vertically stacked structure to grow or maintain intensity. The ideal tropical cyclone has its upper-level circulation directly above the low-level circulation. Changes in environmental wind speed or direction with height will tilt the vertical structure. This tilting inhibits growth and may cause the system to decay.
  4. Unstable atmosphere: Rising air is needed to warm the tropical cyclone core, and an unstable atmosphere is necessary to support rising air.
  5. High atmospheric moisture content: Cloud formation is limited if the atmospheric column is too dry. Rising air will cool but struggle to reach the low dew point. The environment is often stable for dry parcels of air but unstable for moist air.
  6. Upper-level outflow: An exhaust mechanism is needed above a system to perpetuate the strong upward motion. This upper-level mass removal causes the pressure at the surface to drop. As a system develops, low-level cyclonic flow pulls mass toward the center. The flow then turns upward as intense vertical motion associated with thunderstorms. This process is known as “the in-up-and-out” circulation. Without a method to dispose of the mass above a tropical cyclone, low-level converging flow toward the center will halt as the system suffocates.
  7. Adequate Coriolis force: Due to the earth’s rotation, the Coriolis force causes tropical cyclones to spin counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere. This spin is a critical component for development and intensification. Tropical cyclones rarely develop within 5 degrees of the equator, where this force is weakest. See gap in illustration below.

Other Fascinating Discussions

This is just one of dozens of fascinating topics in Flynn’s booklet. Among other things, Flynn discusses:

  • The exact meaning of terms used by NOAA and the National Hurricane Center. For instance, do you know the difference between a potential tropical cyclone, tropical cyclone and tropical depression? See pages 7-8.
  • How tropical cyclones dissipate and transition into extratropical storms. Page 14.
  • The size of the impact area for tropical cyclones. Page 15.
Largest and smallest tropical cyclones on record. Source: NOAA’s Mariner’s Tropical Cyclone Guide by Dylan Flynn. NM stands for nautical miles (about 6,076 ft).
  • What 50 foot waves look like to a sail drone from inside the eye of hurricane. Page 22.
  • How dangers differ in different areas around cyclones.
  • Seasonal variations and the influence of El Niño.
  • Environmental steering currents for cyclones.
  • How to interpret NOAA’s technical charts and tables, such as wave heights/intervals, wind forecasts, etc.

The general public and weather enthusiasts will find a boatload of useful information in this booklet, not just the necessary ingredients for a tropical cyclone.

Posted by Bob Rehak on 7/22/2023

2153 Days since Hurricane Harvey

Hurricane Season Above Average So Far

NOAA’s National Hurricane Center issues a monthly Atlantic Tropical Weather Summary during hurricane season. For June 2023, it shows above normal tropical cyclone activity and and above normal accumulated cyclone energy (ACE) for the North Atlantic, Caribbean and Gulf of Mexico.

#4 for Year and Counting

Three named tropical storms (Arlene, Bret, and Cindy) formed in the basin during June. The report also shows an unnamed storm in January, that in retrospect appears to have been tropical in strength.  

Bret brought tropical-storm-force winds to portions of the Lesser Antilles, while Arlene and Cindy remained over open water and did not impact land.  

So far, seasonal activity has been above average based on the 30-year climatology (1991-2020), where a named storm typically forms about once every year in June. 

peak of hurricane season
Timing of hurricanes in the last hundred years shows peak at September 10.

In terms of Accumulated Cyclone Energy (ACE), which measures the strength and duration of tropical storms and hurricanes, activity in the basin so far in 2023 has also been above average compared to the long-term (1991-2020) mean.

Reports on individual cyclones, when completed, are available at the National Hurricane Center website.

Summary Table

Name                       Dates              Max Wind (mph)

———————————————————–

Unnamed STS*                                              

TS Arlene                  1-3 Jun                 40

TS Bret                  19-24 Jun                 70

TS Cindy                22-26 Jun                 60

———————————————————–     

* An unnamed subtropical storm formed in mid January. Exact dates and maximum winds will be provided once the post-storm analysis is complete.

As of this writing on 7/5/23, NHC predicts NO tropical storm activity anywhere in the Atlantic basin for the next seven days.

Predictions Vs. Actual

In May, both NHC and Colorado State University predicted that this tropical storm season would have about normal hurricane activity. Both sources cited conflicting trends as the basis for their predictions. We currently have above-normal sea-surface temperatures throughout most of the Atlantic basin. We also are now under the influence of an El Niño, which tends, in this latitude, to produce wind shear that discourages cyclone formation.

To improve predictions, NOAA has made a number of changes in reporting at the National Hurricane Center. They include new, improved models for hurricane forecasts and storm surge, longer-range hurricane outlooks, an excessive rainfall outlook, inundation mapping down to the street level, and improved data-collection technologies.

Posted by Bob Rehak on 7/5/2023

2136 Days since Hurricane Harvey

Tropical Depression 2 on Day 1 of Hurricane Season

According to the National Hurricane Center, a tropical depression has formed in the northeast Gulf of Mexico on this, the first day or hurricane season. The NHC gave the storm only a 10% chance of formation just two days ago. They upped that to 50% this morning. This afternoon, it turned into a tropical depression and should turn into a tropical storm by this evening.

Source: National Hurricane Center, Thursday June 1, 2023 at 4PM.

There is NO threat to the Texas coast and NO impacts are currently expected across the Texas coastal waters.

Jeff Lindner, Harris County Meteorologist

A USAF mission this afternoon along with coastal radars and ship/platform/buoy data indicate that the elongated area of low pressure over the northeastern Gulf of Mexico has become defined enough to be declared a tropical depression.

The plane found current wind speeds of 35mph. A tropical depression becomes a tropical storm when winds reach 39 – 73 mph.

WSW/SW upper-level winds are currently shearing the storm. Nearly all of the heavy weather is located to the north and northeast of the circulation.

Convection has been moderate today, but heavy thunderstorms near the center are possible tonight into early Friday.

The depression has drifted slowly this afternoon. Little forward motion is expected tonight. See visible satellite loop:  Visible Satellite Loop for Invest 91L | Tropical Tidbits.

Track Will Take Storm Toward Cuba

The tropical depression is meandering over the northeast Gulf of Mexico, but will begin a slow southward motion on Friday and into the weekend as the depression becomes influenced by  the western portion of a trough over the western Atlantic.

This is an unusual steering pattern over the eastern Gulf of Mexico. The more typical easterly or southerly steering patterns are not yet fully in place. Mid-latitude influences are still reaching well into the Gulf of Mexico. The depression will continue southward into the weekend.

Intensity Forecast 

The system could gain modest organization before much stronger WNW/NW upper level winds impact the system late Friday into the weekend.

The depression could attain minimal tropical storm intensity by 8PM eastern time. However, beyond Friday, upper level winds will become increasingly hostile. The system will eventually dissipate over the southeastern Gulf of Mexico, according to Lindner.

The first subtropical storm of the year actually formed in late January, in case you were wondering. Despite the early start, the NHC still predicts a near normal hurricane season.

Posted by Bob Rehak on 6/1/2023

2102 Days since Hurricane Harvey

NHC Predicts Near Normal Hurricane Season

Hurricane season starts this week. Offsetting factors, some of which would call for an above-normal hurricane season and others of which would call for a below-normal season, led forecasters at the NOAA Climate Prediction Center to split the difference in their seasonal outlook.

They are giving almost equal probabilities to average, above-average, and below-average seasons. But average gets a slight edge. See below.

NOAA predicts 12 to 17 named storms (winds of 39 mph or higher). Of those, 5 to 9 could become hurricanes (winds of 74 mph or higher), including 1 to 4 major hurricanes (category 3, 4 or 5; with winds of 111 mph or higher). NOAA has a 70% confidence in these ranges.

2023 Hurricane Season Names

Below is a list of storm names for this hurricane season.

Source: National Hurricane Center

Competing Factors Make Forecast Difficult

Competing factors both suppress and encourage storm formation.

After three hurricane seasons with La Nina present, NOAA scientists predict a high potential for El Niño to develop this summer. It can suppress Atlantic hurricane activity.

El Niño’s strong winds from the west produce sheer that can discourage tropical storms approaching from the east.

However, favorable conditions include:

  • Above-normal west African monsoon formation that produces some of the stronger and longer-lived Atlantic storms
  • Warmer-than-normal sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea which creates more energy to fuel storm development.
Updated May 29, 2023. For more information, see this page on methodology.

The last two factors have produced more active Atlantic hurricane seasons since 1995, according to NOAA.

New Policies, Models, Technologies Will Improve Future Forecasts

To improve forecasts, NOAA is adopting new policies, forecasting models and technologies this year. Improvements include:

  • In late June, the Hurricane Analysis and Forecast System (HAFS) will become operational. HAFS will become NOAA’s primary hurricane model. Compared to previous models, it improves track forecasts 10-15%.
  • A Probabilistic Storm Surge model upgrade gives forecasters the ability to run the model for two storms simultaneously.
  • The National Hurricane Center’s Tropical Weather Outlook graphics will expand the forecast range from five to seven days.
  • Over the last 10 years, flooding from tropical rainfall was the single deadliest hazard. To give communities more time to prepare, the Weather Prediction Center is also extending the Excessive Rainfall Outlook two days. It will now provide forecasts up to five days in advance. The outlook shows general areas at risk for flash flooding due to excessive rainfall.
  • The National Weather Service will unveil a new generation of forecast flood inundation mapping for portions of Texas in September 2023. These maps will show the extent of flooding at the street level.
  • New small aircraft drone systems, the deployment of additional saildrones, underwater gliders, and WindBorne global sounding balloons will fill critical data gaps and improve hurricane forecast accuracy.
  • Upgrades to the Tropical Atmosphere Ocean buoy array will provide new capabilities, updated instruments, more strategic placement of buoys, and more detailed observations.

NOAA emphasizes that its hurricane forecast is not a landfall forecast. Many storms die at sea and never reach land.

Peak of Season Still Three Months Away, But…

The Climate Prediction Center will update the 2023 Atlantic seasonal outlook in early August, just prior to the historical peak of the season.

peak of hurricane season

Historically, the peak of hurricane season hits on September 10. However, storms can develop any time of year. Interestingly, NHC determined that a subtropical storm formed in the Atlantic Basin in Mid-January 2023.

And minutes after I first posted this story, the National Hurricane Center issued this 7-day outlook. It shows a disorganized area of showers and thunderstorms over the central Gulf of Mexico trying to get organized. But the chances of tropical formation are slim: 10% in the next two days and 20% in the next seven.

So remain alert and prepared.

Posted by Bob Rehak on 5/30/2023

2100 Days since Hurricane Harvey


Hurricane Hunter Expo at Ellington Draws Crowd

To kick off National Hurricane Preparedness week, the U.S. government sent two hurricane hunter aircraft to Ellington Field today. It was a rare opportunity for the public to interact with crews and support staff, and to tour some impressive displays of technology. See pics below.

Hurricane Hunter Aircraft on Display at Ellington Field

WP-3D – “Orion” by Lockheed. Introduced in 1976. the W stands for Weather. Operated by 53rd Weather Reconnaissance Squadron of the U.S. Air Force Reserves.

The versatile WP-3D – “Orion” turboprop aircraft is equipped with a variety of scientific instruments, radars, and recording systems for both in-situ and remote sensing measurements of the atmosphere, the earth, and its environment. Orion aircraft collects low-altitude data to fill gaps in data not available from ground-based radar or satellite imagery.

A crew member described the aircraft as a flying MRI machine that can see into the heart of storms.

WC-130J – “Hercules”, also by Lockheed is larger and heavier.

The WC-130J is a high-wing, medium-range aircraft used in several weather reconnaissance missions throughout the year. The Air Force configured this plane to penetrate tropical disturbances and storms, hurricanes and winter storms. It is equipped with meteorological instruments and radar to obtain data on the current development, movement, size and intensity of these systems.

The aircraft carries a minimum crew of five: pilot, co-pilot, navigator, aerial reconnaissance weather officer and weather reconnaissance loadmaster. The crew collects and reports weather data as often as every minute.

Members of the public look at the impressive number of missions this hurricane hunter has flown.

Dropsonde Demo

Tube through which instrument sensors called “sondes” are dropped from WC130 into hurricanes.

In flight, the aircraft drops sondes about every 15 minutes, according to one manufacturer. “Dropsondes play a very important role in the data collection during field projects. They provide data of a near-vertical profile of very remote regions that could otherwise not be be studied. The dropsonde provides actual readings of the atmosphere as it travels downward. Because the device is in contact with the medium that it is measuring, this type of sensing is also called in-situ sensing.” They measure temperature, wind speed, wind direction, moisture, location, atmospheric pressure and more.

Emergency Management Participants

Also present were representatives from NOAA, the National Hurricane Center, the National Weather Service, the Army Corps of Engineers, the Coast Guard, the US Air Force, Harris County Flood Control District, the City of Houston Mayor’s Office of Emergency Management, the Red Cross, USAA, and more.

They passed out everything from disaster preparedness guides to hurricane guides, emergency document bags, cloud charts, and stress balls! Good times and sunburns were had by all!

Additional Preparedness Resources

From Houston, the tour moves east to New Orleans, and Mississippi before making two stops in Florida.

In addition to the list of preparedness links I posted yesterday, the handouts today reminded me that I should have posted:

The last guide goes beyond hurricanes and covers everything from chemical spills to active shooter incidents.

They’re all worth exploring. But don’t wait until a hurricane is bearing down to explore them. The sites will likely be crowded, the internet down, and response times slow. Also keep in mind that in an emergency, you may need to conserve battery power in your mobile devices. After Hurricane Ike in 2008, parts of the Lake Houston Area lost power for weeks.

Posted by Bob Rehak on 5/1/2023

2071 Days since Hurricane Harvey

NHC Gives 40% Chance of Formation to 91L Within 5 Days

Another tropical wave is moving into the Caribbean along the same track as Ian. As of Monday morning at 8 a.m., the National Hurricane Center gives it a 40% chance of developing within 5 days. Currently, the tropical wave is several hundred miles east of the Windward Islands and moving westward at 15-20mph. The NHC has designated this area of investigation as 91L.

Atlantic tropical waves and directions. Invest 91L is orange.

While Invest 91L looks fairly impressive on satellite images (see below), Jeff Lindner, Harris County meteorologist says, “There does not appear to be any closed low-level circulation yet. This wave should reach the eastern Caribbean Sea around mid-week and the western Caribbean by this weekend.”

91L is the storm north of the Guyanas and Suriname on the north coast of South America.

Says Lindner, “Conditions generally become favorable for development along the track of 91L, but when compared to Ian, model solutions are much more varied with development potential and also much more scattered. Some models take the storm into Central America, others predict it will track toward Puerto Rico and the Dominican Republic.

From Tropical Tidbits.

For now, watch and wait.

Orlene Moves Inland Over Mexico

In the meantime, the eastern Pacific is fairly active. NHC is tracking three storms. Two are moving northwest parallel to the Mexican coast as a third – Hurricane Orlene moves inland near Mazatlán.

Mid- and high-level moisture from Orlene will stream across our area later in the week. However, our air is so dry right now that precipitation aloft will likely not reach the ground.

Glancing Blow from Frontal Boundary Later in Week

Lindner also predicts, “Toward the end of this week, moisture may return to Texas from the Gulf of Mexico ahead of a front that will drop into the eastern U.S. The front should only strike a glancing blow to Texas. Most of it will head more southeast toward the Tennessee Valley. So rainfall potential for Houston will remain low. Our dry pattern will likely continue.”

The National Weather Service Storm Prediction Center sees little to no severe threat.

Posted by Bob Rehak on 10/3/2022 at 11:30 am

1861 Days since Hurricane Harvey

Another Tropical Wave Headed Toward Gulf

By this weekend, the second tropical wave in two weeks will make its way into the Gulf of Mexico. The National Hurricane Center (NHC) is monitoring a disturbance in the southwestern Caribbean. They predict it will track northwest across Central America and the Yucatan. Then it should emerge into the Gulf of Mexico later this week.

It’s too early to tell the exact track, timing or degree of development. That depends on many factors such as steering currents and frontal boundaries. But as of 7am Houston time on 8/16/22, NHC gives the disturbance a 20% chance of developing into a named storm within 5 days.

NHC says an area of low pressure could form on Friday. Gradual development of this system is possible while it moves northwestward over the southwestern Gulf of Mexico through the weekend.

15:20 Zulu time is 10:20 Houston time. Note the cloud formation in lower left over Nicaragua and Honduras.

Harris County Meteorologist Jeff Lindner says conditions will become increasing favorable for tropical cyclone development in the Bay of Campeche (the area with the yellow circle). He points to a frontal boundary dropping south toward the Texas coast late this week and says areas south of that boundary will become increasingly favorable for a low pressure system to develop along the axis of the tropical wave.

Weather Service Storm Prediction Center 3-Day Outlook shows front moving across southern plains on Friday.

However, there’s no reason to panic now. Just watch the National Hurricane Center website closely over the next several days for any changes.

Almost exactly 5 years ago, a storm followed a similar track across the Yucatan. It eventually became known as Hurricane Harvey.

Posted by Bob Rehak on 8/16/2022

1813 Days since Hurricane Harvey

Slight Chance of Tropical Formation In Gulf This Weekend

The National Hurricane Center (NHC) issued a tropical weather outlook today that shows a 10% chance of tropical formation in the Gulf. This is your “heads up.” Hurricane season is ramping up.

NHC will provide an update on chances for development later this evening, but models show growing support that a tropical depression or weak tropical storm is possible along the middle or lower TX coast by Sunday. The system will then moving inland over south Texas late Sunday into Monday, according to Jeff Lindner, Harris County’s meteorologist.

Latest Satellite Imagery

Here’s what the Gulf looks like on satellite Friday evening. The system will track W to WSW over 85-90 degree waters toward the mid- or lower-Texas coast on Sunday.

4:51 PM Houston DST

Currently, disorganized showers and thunderstorms over the north-central Gulf of Mexico are associated with an area of low pressure centered just offshore of the southern coast of Louisiana. There’s no tropical formation yet. But that could change.

As of 2PM EDT today, NHC listed the formation chance through:

  • 48 hours…low…10 percent.
  • 5 days…low…10 percent.

Rainfall Potential

Regardless of development, locally heavy rains are possible along portions of the Texas coast through the weekend. For more information about the potential for heavy rainfall, please see the National Weather Service site and the Weather Prediction Center.

Highest rain chances in next few days for SE Texas are around mid-day Saturday.

Decent rain chances exist for the next three days, especially along the coastline south of I-10.

Jeff Lindner, Harris County’s meteorologist says, he expects most of the shower and thunderstorm development associated with this low pressure system to happen near the coast and offshore. He expects lesser chances inland to the north as high pressure and drier air begins to build southward from the northeast. 

Forecasters use a measurement called PWS (Precipitable Waters) to predict amounts of rainfall. PWS measures the amount of water vapor in a column of air. This weekend with PWS of 2.2-2.3 inches and possible cell training, Lindner warns that a quick 2-3 inches of rainfall in less than an hour will be possible. Even though grounds are dry and should be able to handle the rainfall, some street flooding will be possible with those rates.

No River Flooding Expected

However, National Weather Service expects no significant river flooding in the next five days.

Tide Report

According to Lindner, tides are already elevated along the coast due to the full moon. Easterly and southeasterly low-level winds on the north side of the low may bump seas up a bit over the weekend and push tides a little higher. He expects water to be way up on the beaches at high tides over the weekend.

Monitor forecasts closely over the weekend for any changes.

Posted by Bob Rehak on 8/12/2022

1809 Days since Hurricane Harvey

Western Caribbean Could Get Active This Week

(Updated at 1:30p.m. 6/13/14 to reflect increased risk) According to Harris County Meteorologist Jeff Lindner, a tropical system may form over the western Caribbean Sea this week. The National Hurricane Center has increased the probability of formation from 20% to 30% to 40% so far today.

NHC gives the yellow area a 30% chance of formation as of 8am EDT on 6/13/22.
Upgraded to 40% chance of formation as of 1PM Houston time, 6/13/22.

Converging Systems

Currently, a trough of low pressure extends from the eastern Pacific Ocean (south of Mexico) across central America into the far western Caribbean Sea. It is producing numerous clusters of showers and thunderstorms. Additionally, a westward moving tropical wave is starting to interact with the eastern part of that trough. See below.

Satellite image of Atlantic Basin as of 9:50 Houston time on 6/13/22. Note the area starting to curve around Central America and the westward moving storm off the cost of South America.

Thunderstorm clusters over the eastern Pacific are in the formative stages of tropical development. Meanwhile, showers and thunderstorms over the western Caribbean remain disorganized and in an environment generally of strong upper level westerly wind shear.

Global forecast models show varying degrees of development over the western Caribbean Sea east of Honduras by mid week.

Jeff Lindner, Harris County Meteorologist

Most models indicate development very near the eastern coast of central America. And it is possible that no development happens due to the close proximity to land and/or wind shear.

Should this surface low actually develop, the sprawling ridge of high pressure over the southern plains responsible for our current heat wave will affect forecasts.

Without any sort of defined center for the Caribbean system, confidence is low on where anything may form and eventually move. However, the majority of the global models keeps this disturbed area close to central America and then potentially in the Bay of Campeche.

National Hurricane Center Forecast

The National Hurricane Center agrees. It currently gives the feature a 40% chance of formation over the next 5 days. That’s up from 20% yesterday and 30% this morning.

At a minimum, the NHC predicts that an area of low pressure will develop by the middle part of this week over the southwestern Caribbean Sea. Forecasters add: “Some slow development of this system is possible thereafter while it drifts generally northwestward off the coasts of Nicaragua and Honduras.”

 Check National Hurricane Center Daily During Season

This should serve as a reminder that we are in hurricane season. And it is a good idea to check the tropical weather outlook at least once per day.

The best place to do that is the National Hurricane Center website. While the statistical peak of hurricane season is still three months away (September 11), life threatening tropical systems do strike in early in the season. Here’s an interesting article about devastating June storms.

Many people in the Houston area will remember Tropical Storm Allison in 2001. It killed 22 people and dumped almost as much rain as Harvey. It caused all the flood maps to be revised at the time.

Posted by Bob Rehak on 6/13/2022

1749 Days since Hurricane Harvey