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Hot and humid with isolated t-storms through Wed. Stronger storms possible Thursday.

We’re already seeing that high humidity this morning. That high humidity, along with that hot sun, will make the atmosphere ripe for scattered afternoon and evening t-storms. Highs both Tuesday and Wednesday will top out in the lower 80s, with lows near 70. What you get today in the weather is what you’ll get on Wednesday. On Thursday, a cold front will begin flirting with our area, and that will lead to some stronger storms. Some of Thursday’s storms could contain some hail and marginally severe winds. I’ll keep an eye on it! The heat and humidity continue for Friday through Sunday, with isolated to scattered heat-of-the-day t-storms. There are indications that a stronger cold front will come through here around Tuesday, bringing lower humidity and cooler temps. I’ll keep an eye on that too!

I hope you got to check out the International Space Station last evening? It was a site to see once again. I’ll try to keep you posted on when the next one will be. Remember, you can watch it track across the earth live at http://www.isstracker.com/, as well as get texts reminders of when it will be flying over your neighborhood at https://goo.gl/LMQKyO.

Since it is so hot and humid out today, I’ll leave you with a pic of a place that might cool you off a bit. Isn’t that beautiful? This photo was taken by Tim Sherrill, father of our very own Emily Sherrill.

Now, when we leavin’ for the beach? 🙂

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Summer has arrived!

Technically, Summer doesn’t arrive until  June 20th, but you’ll beg to disagree with that this week. You may have already noticed that the humidity has really increased out there. It’s going to feel hot and muggy all week, with afternoon and evening showers and thunderstorms. Each day will feature highs in the low to mid 80s, and overnight lows in the mid to upper 60s. The best chance of rain right now looks to be on Thursday, as a front creeps closer to our area. Basically, just know that it’s going to be hot and humid with scattered thunderstorms each afternoon and evening.  As usual, some of the storms could be strong, with gusty winds and lots of lightning, but no widespread severe weather is expected at this time.

You may have noticed that beautiful full moon over the weekend? It was quite the site to see! Facebook follower Inga Sarda-Sore snapped this pic of the moon as it was rising over New York City. The city is beautiful enough as darkness fall, but throw in that moon and it’s absolutely gorgeous.

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On top of that beautiful moon rising, the International Space Station (ISS) flew right over my house Friday evening. It was so bright and easy to see. You can track the ISS live at http://www.isstracker.com/. Then, you can always know where it’s at! It’s really cool to watch. Check it out! You can also get free text messages from NASA that will alert you to when the ISS will be flying over your neighborhood. I get these and I highly recommend it. You can sign up at https://goo.gl/LMQKyO.

Would you take a ride on the ISS if given the chance? I would just to see a hurricane from space. How cool would that be? 🙂

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Warm. Dry. Sunny. Repeat. That’s pretty much the forecast for the next three days! Mostly sunny skies will allow us to warm to near 80 today and into the low to mid 80s over the weekend. Clear skies at night will allow temps to drop to near 60. Humidity will be increasing each day, so you’ll likely feel that change, especially by Sunday. The next chance of rain comes Monday, as we heat up to a muggy 85 degrees. An isolated shr or storm is possible by the afternoon/evening. Those rain chances tick up to about 40% or so by Tuesday and Wednesday, again, mainly afternoon and evening heat-of-the-day type stuff.

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That picture is one of the few taken of the worst tornado to ever strike New England. The one-mile wide twister hit Worcester, Massachusetts on June 9, 1953. It took the lives of 90 people as it tracked for 46 miles. The tornado bent steel towers that were built to withstand winds of up to 375 mph! The storm dropped debris on Boston and then out into the Atlantic Ocean.  1953 was the third deadliest year for tornadoes in the US, with 519 lives lost. This is in spite of the fact that tornado counts were below average that year. Of the 519 killed, two-thirds of those were lost in only three tornadoes (Flint, MI, Waco, TX, and Worcester, MA).  This emphasizes the point that we try to make with hurricane season. You don’t have to have an active year to have a bad year. It only takes one storm.

Incidentally, 1953 caused the Storm Prediction Center (SPC) to reorganize. The Flint and Waco tornadoes had been forecast, but the Worcester was a complete surprise (it was 1953, after all). At that time, the SPC consisted of young men who had gained their meteorological training while serving in the military during WWII.  Many of them had less than 10 years experience.  One of the men was Joseph Galway, the inventor of the “lifted index” that we use today as a severe wx parameter. The birth of convective outlooks came out of all this, a product that many of us everyday. The size of severe wx watches was also reduced and is comparable to what we use today.

The reorganizing of the SPC must have worked because we hadn’t seen a tornado with such death tolls until 2011, with the super outbreak in the South and then again with Joplin.

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Tornadoes associated with the cold core low in North Dakota on June 8, 2017

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Last night, I shared the video of the tornado in North Dakota. As you may have noticed, there was no precipitation surrounding the tornado. We often see supercell tornadoes that are either wrapped in rain, or on the brink of becoming wrapped in rain. The supercells in the southern US tend to form in much more humid environments. These humid environments are made possible due to the close proximity of the Gulf of Mexico. As one gets farther away from the moisture source, there’s less moisture to work with. There are “hiccups” to this idea, in that areas with lots of agriculture (ie. Corn fields of Indiana) have noticeable jumps in humidity due to evapotranspiration of the crops (moisture evaporating from the crops).
The main culprit for yesterday’s tornadoes was what we refer to as a cold core low. This is basically a cold pocket of air spinning in the atmosphere. It is not based on the surface of the earth, like a hurricane’s low pressure center, but it is based much higher up within the atmosphere. This spinning pocket of cold air is rather common across the Plains, especially during the spring months. Now, if you can get a lot of sunshine underneath these lows, that sunshine will warm the earth’s surface. Since we’re getting a higher sun angle every day that we closer to the first day of summer, it can really warm the ground up this time of year! That warm air underneath that pocket of cold air above can create the perfect environment for clouds to develop, as that warm air rises into the cold air and cools and condenses. The winds with these cold core lows increases pretty dramatically with height, so that adds a component of shear. In other words, the faster winds aloft allow the updraft to tilt, which allows it to gain/maintain strength without being choked out by the nearby downdraft.
With winds increasing with height (speed shear) and instability (sun heating the ground), the ingredients were in place for thunderstorms. An area of surface low pressure then formed just southwest of where the tornadoes were reported. This development produced a frontal boundary across eastern North Dakota and provided directional shear for the winds. Speed shear is when winds increase with height, directional shear is when winds change direction with height. We now have southeast winds at the surface, increasing and becoming southwesterly aloft, which is the perfect wind combination for rotating supercells. The only thing left to talk about is surface moisture and that’s what leads us to the next point: why is there no precipitation around the tornado?
Interestingly, a cold front had made its way across the Dakota’s earlier in the afternoon. That front robbed the atmosphere of some of its moisture. However, dewpoints were still able to climb to around 60, which was just enough moisture to create thunderstorms. That’s enough to create the rotating thunderstorm, but not enough to produce a lot of precipitation. We call these ‘low precipitation supercells’ and they’re actually rather common across the northern Plains. Remember the guy mowing his yard during that very visible tornado in Canada a week or so ago? Same situation! There’s enough moisture to create a storm, but too little moisture for the storm to produce heavy precipitation. In the southern Plains we may see dewpoints in the 70s with supercells, which is more than enough moisture to not only create storms, but create storms that produce copious amounts of moisture that can wrap around the rotating supercell and hide the tornado.
If the sun hadn’t come out and heated everything up so much, there wouldn’t have been enough instability to create thunderstorms. Plus, without that warming the surface low that formed wouldn’t have been as strong, and the wind fields would have been weaker. It really all boils down to that sunshine and that cold pocket of air that we call a cold core low.
The tornado has been rated an EF-0 by the NWS. Cold core lows often produce weak tornadoes, and that certainly seems to be the case here.
I hope this helps you understand how the tornado originated and why we were able to see it! If you have any questions at all, please don’t hesitate to let me know!
For more radar, satellite, storm environment, etc information, go to http://www.weather.gov/fgf/2017_06_…