What is thunder? How hot is lightning?

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

Heavy Rain Event for North Texas on Friday 10/30

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

Predicted Heavy Rain Event is Underway; DFW Rainfall Record Broken

➡︎ 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

Heavy Rain Event for N. Texas this weekend (10/22 – 10/24)

  ➡︎  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 Top 20 Snowstorms & Temperature Trends

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

Watch a Full Year of Changing Seasons from Space

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

Equinox: Why the Length of Day & Night are Not Equal

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

What is the Difference Between a Hurricane and a Typhoon?

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

Hurricane Records Broken As 3 Major Pacific Hurricanes Coexist

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

Hurricane Katrina: The Dire NWS Warning That Saved Lives

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

Hurricane Hunter P-3 Tail Radar on Google Earth

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

DFW: Strong August Cold Front On Track For N. TX Wed (8/19/15)

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

How Many Lives Have Been Saved By Improved Hurricane Forecasts?

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

Rapid Intensification of Tropical Storms & Hurricanes in the North Atlantic

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

Hurricane Irene’s (1999) post-landfall intensification and downbursts

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

Brown ocean effect: Saturated soil intensify tropical cyclones

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

What is the water cycle and can the cycle be disrupted?

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: DFW’s Wettest May on Record

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

Dallas & Irving Tornado on Sunday, May 24, 2015

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

DFW: Heavy rain, thunderstorms, & flash flooding Memorial Weekend

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

Strong Tstorms & Flash Flooding Poss for DFW Sat-Sun 5/9 – 5/10

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

Historic Rainfall Event in the Oklahoma City Metro on 5/6/15

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. Update: The rainfall total has been updated to reflect the final official amount as confirmed by the NWS.  The change was minor (a tenth of … Read more

DFW: Tstorms Late Weds (4/22) May be Severe w/ Localized Flooding

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

DFW: Severe Thunderstorms Likely Saturday Evening (4/18)

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

Much-Needed Rain For N. TX Today (4/8) & Severe Tstorms Tomorrow (4/9)

UPDATE: Thursday 4/9 at 4 pm [Update Regarding Convective Initiation]: My map yesterday placed convective initiation along a McKinney to DFW Airport to Stephenville line.  I am adjusting it west by about 20 miles to from Pilot Point to Fort Worth to Stephenville.  This shift wouldn’t normally be significant (it’s within the margin of error), … Read more

Spring Freeze for the Southeast Next Weekend (3/28-3/29)

→ Read my initial forecast published on Saturday, March 21 Final Update – Observed Low Temperatures on the morning of March 29, 2014 The freeze that was predicted for over a week verified perfectly. All locations in northern Georgia fell below freezing for 4 or more hours Saturday night/Sunday morning. I’ve gone through the observations, … Read more

Thunderstorms with Heavy Rain Likely over N TX Thurs Night & Friday (3/20)

Update #5 Friday 3/20 at 1:30 pm [Final Update]:   A few official rainfall amounts over the past 24 hours Sister Grove Ck (Collin): 1.86 Melissa (Collin): 1.43 Prosper (Collin): 1.24 Dallas, Irving Blvd (Dallas): 0.51 Gainesville (Cooke): 1.56 Valley View (Cooke): 1.67 Denton (Denton): 0.81 Ladonia (Fannin): 2.93 Celeste (Hunt): 2.17 Alvord (Wise): 1.14 Update … Read more