Author: Jason Cooley

#WeatherWednesday – Lake Effect Snow

Happy #WeatherWednesday everyone! Now that we got our first taste of colder air across the Southern Plains, we switch from talking about hurricanes to talking about winter weather! Meteorological winter starts in under two months (December 1). Lake effect snow is a term heard a lot in the Midwest and Northeast US. This phenomenon is common over the Great Lakes region in late October through late January, but in some cases can occur as late as March and early April. Lake effect snow requires several ingredients to come together. These conditions can last for a few hours or a few days. L.E.S. in general is easy to forecast and almost a certainty to exist if you know what to look for in upcoming weather conditions. Relatively cold low level flow (below freezing) after cold front passages that encounter lengthy travel over unfrozen and warmer lake surfaces will modify due to thermal energy release from the water to the air. Once the flow reaches the lake shore after warming and gaining liquid water content, it encounters colder air. The onshore flow suddenly rises over the cold land air due to the air density differential. When it rises it gets colder and condenses and the surplus water content picked up over water precipitates downwind over land as snow. Water has a high specific heat capacity, so a lake holds its heat...

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#WeatherWednesday – Naming a Hurricane

Happy #WeatherWednesday everybody. The last write-up was about Hurricane Ike on the 9th year anniversary of landfall in Texas! Today we stay on the category of hurricanes. We call hurricanes by name, a practice popularized in the early 1950s. How are they named and how do hurricane names sometimes get retired? As most of you know, tropical cyclones with maximum sustained winds of 74 mph or more are called hurricanes in the eastern Pacific and the northern Atlantic Oceans. However, they are recognized and named before they strengthen to this point. NHC (National Hurricane Center) recognizes any areas of organized convection in circular flow as tropical depressions. Once known as a depression, the NHC will update their probability of intensification to a tropical storm several times per day. If the depression reaches tropical storm intensity at 39mph+ sustained winds then it is given a name! This name will be associated with this storm for the rest of its life until it no longer has an organized center of low pressure. When naming tropical storms in the N. Atlantic, the WMO (World Meteorological Organization) simply has a list of names for each year that are alphabetized and alternate between male and female names. Every odd year begins with a female “A” name, and even years start with a male “A.” There is one name for each letter except for the...

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#WeatherWednesday – Hurricane Ike

Happy #WeatherWednesday everyone! This weekly blog has taken a brief hiatus as Texas was being affected by Hurricane Harvey and Florida by Hurricane Irma. Our thoughts and prayers go out to everyone affected by these tragic storms. Things have settled down for now, just in time to discuss a piece of Texas weather history. Today is the 9th anniversary of Hurricane Ike’s landfall in Galveston, TX. Before 2017, Ike was the third most costly Atlantic tropical system. It likely won’t hold this placement after the official cost assessment of recent Hurricanes Harvey and Irma is announced. Ike really messed up Haiti and killed 74, cost a lot of damage in the US and killed 113, and overall killed 195 people. Here is the path with color-coded intensities: Ike made landfall in Cuba as a Category 4. On this day at 2AM 9 years ago, after a trip through the Gulf of Mexico, Ike made landfall in Galveston as a high end Cat-2 with 110mph winds! Ike didn’t dissipate until it blew past the Great Lakes and well into Quebec on the 15th. It affected the Houston/Galveston metro, the Ozarks, and the Lower Ohio Valley/Great Lakes with damaging winds and dangerous flooding. This wind damage actually tied the Xenia tornado outbreak as the costliest storm event in Ohio (1.1 billion USD). Canada also had record setting flash flooding from Ike....

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#WeatherWednesday- Derecho

Hello everybody and happy #WeatherWednesday! Last week we discussed the concept of the monsoon. Today we will talk about a type of storm called a “derecho”. The word is Spanish for straight and it has to do with straight line winds! A derecho isn’t the most common storm, but it’s definitely dangerous. These storms occur several times per year in the USA. They are storm systems associated with high surface winds from storm outflow. The longevity and elevated forward speed of the damaging storm are primary defining factors. This means more area liable to be damaged by a storm moving faster than normal. Many derechos propagate at 35-65mph. Storms can produce locally high winds and damage anytime, but derechos produce high winds for hours over a great length and width. A squall line on the other hand usually produces sporadic wind damage at various parts of the storm. A squall is similar in structure but is only considered a derecho if there have been 60mph+ winds on the storm front for at least 6 hours. A serial derecho can commonly be identified as a bow echo or backward C on radar reflectivity during its lifetime. Visually, a shelf cloud normally develops on the leading gust front where the temperature gradient from colder outflow and warm inflow exists. Derechos occur in the summer most of the time when warm air...

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#WeatherWednesday – The Monsoon Season

Happy #WeatherWednesday everyone! I hope the lesson on RFD cleared up any confusion you had about its meaning! We will return to talking about supercell characteristics at a later time. With the recent weather business going on in the southwest USA, I would like to talk a bit about it. This isn’t unusual for the interior southwest. Places like Arizona, New Mexico, Nevada, Colorado, California, Utah, and sometimes Trans-Pecos (Texas) experience numerous storms virtually daily around this time every year. It’s called a monsoon! The North American Monsoon usually starts in July and lasts into mid-September. The rain and...

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