How does the first freeze compare with normal (climatology)? ❄️ The average first freeze at DFW is November 22. Therefore, this year’s freeze was right on schedule, based on the current 30-year average (1981-2010). Other Freeze Statistics for DFW: Average first freeze: November 22 Average last freeze: March 13 Earliest freeze on record: October 22, … Read more
The fluid dynamics associated with atmospheric disturbances cause the downstream air (ahead of the disturbance, before it arrives at a location) to rise, and the upstream air (behind the disturbance, i.e., after the disturbance has passed) to sink. If there is sufficient moisture in the area of rising air, clouds and precipitation may form. Necessary … Read more
This was a lot of fun for me. The Weather Channel featured me on their “Weather Geeks” show, which is hosted by my friend and colleague, Dr. Marshall Shepherd. My Favorite Photo I have over 30,000 photos in my library, and the first photo shown in the segment is my favorite. This was a historic … Read more
Imagine yourself as a cloud, happily floating over the surface of the Earth without a care in the world. As you drift across the sky, the millions of tiny water droplets and ice crystals that you are composed of brush against each other, causing a buildup of electric charges in your cloud body. The negative … Read more
Final Rainfall Amounts [Posted Saturday 10/31 at 1:25 pm] The NWS in Fort Worth prepared this graphic depicting storm total rainfall amounts. Using the legend, I drew the 2-inch line. Clearly, most of the area saw 2 to 4 inches, but there was an area of 4 to 7 inches in Tarrant, Dallas, Johnson, and … Read more
➡︎ Update History: Initial Forecast (Sunday 10/18) & Updates 2 through 5 | Update #6 | Update #7 Forecast Verification and Records Tied or Broken ◙ Record #1 [Broken] 2.58 inches of rain at DFW on Thursday 10/22 shattered the previous record for the date (2.19″) set in 1908. ◙ Record #2 [Broken] 3.55 inches … Read more
➡︎ Update History: Initial Forecast (Sunday 10/18) | Update #2 | Update #3 | Update #4 | Results/Records Broken Latest Forecasts (Starting at Update #6 on Friday 10/23) Continued Here Forecast Verification and Records Tied or Broken ◙ Record #1 [Broken] 2.58 inches of rain at DFW on Thursday 10/22 shattered the previous record … Read more
Atlanta’s biggest snowfall events of all time are listed in the table below. The most snow ever recorded on a single day in Atlanta was on January 23, 1940 when 8.3 inches fell. The top 10 snowstorms in Atlanta have a median accumulation of 4.2 inches. View the full list We often hear the cliche: … Read more
I love this animation. After spending years trying to explain these concepts, along comes high-resolution satellite images sewn together from a Lagrangian perspective to create a fast animation that actually shows the seasons changing as Earth tilts on its axis from equinox to solistice to equinox and so on. Credit: Simon Proud, researcher in the … Read more
The autumnal equinox occurs Sunday, September 22, 2024 at 7:43 AM, but the days and nights are not considered equal until Saturday, September 26th. This is because of the atmospheric refraction of sunlight. When a wave encounters a medium whose density differs from that through which the wave has been propagating, conservation of momentum and energy … Read more
A hurricane is the exact same meteorological phenomenon as a typhoon. The difference is simply a function of the storm’s location relative to the International Date Line (180ºW). A “hurricane” west of the International Date Line (IDL) is called a typhoon. The term is believed to have its origins in Sinitic, one of the Chinese … Read more
On August 29, 2015, for the first time on record, three *major* hurricanes were active simultaneously in the central/eastern Pacific (east of the International Date Line, 180ºW). A major hurricane is defined as a category 3 or higher. Yet another record was set at 10 pm CDT. 8 pm CDT 8/29: Three Major Hurricanes Set … Read more
On this, the -year anniversary of Hurricane Katrina’s final landfall east of New Orleans, I wanted to share some graphics and the very rare, dire warning issued the National Weather Service in Slidell, Louisiana that likely saved many, many lives. Radar Loop at Landfall Satellite Loop at Landfall Location of the NWS Brief … Read more
Prior to the advent of weather satellites and aircraft reconnaissance of tropical cyclones during the mid-20th century, the loss of life due to unexpected, landfalling hurricanes was tremendous. In 2015, hurricane forecasting continues to improve thanks to ongoing upgrades in observational technology (aircraft, dropsondes, tail radar, etc.), computational resources, improved numerical prediction models (model resolution, … Read more
Summary & Forecast Verification [Thursday 8/20/15 8 pm] ***Today Among Our Coldest August Days on Record*** A few days ago, I predicted that our strongest cold front in 3 months would move through North Texas (below). The forecast worked out perfectly (and to the contrary of the armchair meteorologists who declared otherwise on the day … Read more
Trends In The Ratio Of Damage To Deaths Caused By United States Land-Falling Hurricanes 24th AMS Conference on Hurricanes and Tropical Meteorology (2000) Chris C. Robbins and James Gross National Hurricane Center, Miami, Florida We have estimated that, if the pre-reconnaissance trend continued at the time of Hurricane Andrew, approximately 4,354 deaths may have … Read more
A Climatology Of Rapidly Intensifying Tropical Cyclones In The North Atlantic Basin, 1975-2000 25th AMS Conference on Hurricanes and Tropical Meteorology (2002) Chris C. Robbins and Stacy R. Stewart National Hurricane Center, Miami, Florida 1. Introduction Rapidly intensifying tropical cyclones pose a significant forecast problem for operational meteorologists. Unfortunately, the climatological nature of such … Read more
I want to kick off this piece with a discussion of Tropical Depression Bill’s intensification over Missouri, hundreds of miles inland. ➡ Click here to skip to the North Texas impacts to see how much rain fell at DFW and what the peak winds were as Bill passed across the area. At 4 p.m. CDT Friday, … Read more
This post is a carryover from the previous post that contained three days worth of forecast updates leading up to the formation of Tropical Storm Bill. In an effort to improve readability, I thought it would be best to create a new post given that T. S. Bill will soon make landfall and subsequently move … Read more
Mesocyclone-Induced Downbursts Associated With The Landfall Of Hurricane Irene (1999) Over S. FL 24th AMS Conference on Hurricanes and Tropical Meteorology Stacy R. Stewart and Chris C. Robbins Tropical Prediction Center, Miami, Florida 1. Introduction This paper examines the occurrence of multiple damaging downbursts or “miniswirls” with the passage of Hurricane Irene across South … Read more
May 2015 was the wettest month ever recorded in the United States since record keeping began 121 years ago according to the National Climatic Data Center (NCDC). The main contributing factor to the nation’s “wettest-May” was the incredible rainfall totals across the Central United States. Meteorologist Chris Robbins posted that May 2015 was the wettest … Read more
Latest Forecast ➡ A new post about Tropical Storm Bill was started to help improve readability. All previous forecast updates in the three days leading up to Bill’s formation are archived below, in the order that they were written. ➡ Final Event Recap: As predicted, peak wind gusts of 50 mph and greater, and record … Read more
A follower asked, “if the water cycle is real, how can there be water shortages?” In light of the recent drought in Texas, which ultimately ended with the historic rainfall during the month of May 2015, and the ongoing devastating drought in California, I thought I would make this brief post. What is the Water … Read more
May 2015 was an exhausting month for forecasters in Oklahoma and Texas. One storm system after another brought enormous rainfall and significant flooding to many areas. I will try to post some dynamics/thermodynamics analyses or a general recap of each individual storm system in a future addendum to this post. For now, I wanted to … Read more
Many of you may have been awakened by the Tornado Warning in western Dallas/eastern Tarrant Counties early Sunday morning. The tornado sirens sounded across the warned area, and even in my area near the Grapevine/Southlake border. Fortunately the tornado in Irving dissipated as it moved north-northwest toward the residential areas of Carrollton. As it turns … Read more
Read Initial Forecast #1 | Use Radar/Advisory Tools on the DFW Page Final Update [Rainfall Record Broken – Sunday 5/24] DFW Airport received 3.31 inches of rain today (Sunday, May 24, 2015), which breaks the record for the greatest amount ever recorded on this date. The previous record was 3.28″ set in 1908. Records date … Read more
Below is my partial/subjective surface analysis using 2 pm data. There is certainly a convoluted mess of fronts associated with this surface low. However, the dry line is obvious with at least one dry-line bulge southwest of the metroplex. Surface-based convective available potential energy (CAPE) in that area exceeds 4,000 J/kg. There is a θe … Read more
Slow-moving, training supercells brought enormous rainfall amounts to the southern Oklahoma City metro on Wednesday, May 6, 2015. Rainfall rates of 3 to 4 inches per hour occurred with the thunderstorms. The rainfall total has been updated to reflect the final official amount as confirmed by the NWS. The change was minor (a tenth of an … Read more
Update #2 [Wednesday 4/22 10:40 pm] ***Severe Thunderstorm Watch*** A Severe Thunderstorm Watch has been issued for the thunderstorms that developed to the northwest as predicted. These continue to move southeast. The watch is in effect until 4 am. Read my initial forecast discussion posted the day before, on Tuesday 4/21 Update#1 [Radar Update – … Read more
Special Update [Saturday 4/18 7:40 pm] Significant thunderstorm wind damage is likely in the path of this downburst throughout Tarrant County, with winds in excess of 70 mph possible. It is moving northeast through Tarrant County. Velocity Image at 7:40 pm: Fourth Forecast Update [Saturday 4/18 5:45 pm] ***Severe Thunderstorm Watch Until 1 am*** Includes … Read more