Friday, April 19, 2019

Dangerous Day in the Middle Atlantic Region

Heads up: Raleigh, Charlotte, Columbia, Richmond and Charleston. Damaging winds and tornadoes are in today's forecast.

Let's break it down. The more serious risk is damaging thunderstorm winds. The significant risk is 15%. The purple area is a high risk of 45%. The hatched area is where wind gusts are forecast to exceed 75 mph!

There is also an enhanced risk of tornadoes.
On this forecast chart, 5% (brown) is the significant risk threshold. The 10% (yellow) is an enhanced risk.

How to prepare:
  • Power failures will be widespread. So, get some extra cash at the ATM and fill your car with fuel well before the storms arrive. If you have a chain saw, fill it as well. [Remember, if power is out, ATM's and fuel pumps will not work.] Power failures could last several days.
  • Fully charge your phone and PC before the storms arrive. Take them off the charger before lightning is present. 
  • If warnings of extreme winds are issued, please shelter like you would a tornado. Preferably a basement under sturdy furniture. If not, a small room in the middle of the house. 
  • If a tornado watch or a "particularly dangerous situation" severe thunderstorm watch is issued, please exit your mobile home find other shelter, perhaps in a community shelter or other sturdy public building. 
  • Wherever you shelter, I recommend wearing shoes, taking a flashlight with good batteries, and a couple of bottles of water into your shelter. If appropriate, take diapers and portable family heirlooms like scrapbooks. 
Please make sure you have at least two independent ways of receiving the warnings! Good luck.

Thursday, April 18, 2019

Something for VORTEX-SE to Research

There is a major tornado research program pertaining to tornadoes in the Southeast. I would like to offer a suggestion for some serious research.

I have been viewing weather radar on a virtually daily basis for 48 years. This afternoon, I saw a phenomena I've seen only one other time which was in the late 1970's in Kansas (I don't remember the date): a gigantic (as these things go) rotating mesoscale vortex that was not associated with a supercell thunderstorm that was apparently spawning multi-vortex, violent, tornadoes. I'm bringing this to research meteorologists' attention because I have not seen any coverage of it in the Mississippi media, so far.

Why is this important? The answer can be easily seen in a video here. A screen capture is below.
It is rare for non-supercells to cause tornadoes of EF-3 intensity which the above image suggests. 

Here are some images of the radar data from this unusual storm. The
"donut" centered just west of Polkville, ten miles in diameter, is unusually large for this type of system. There was a report a few minutes later of a multi-vortex tornado near Polkville.

Here is a wider view with the Doppler wind velocity data on the right. The brownish white tints are
winds above 100 mph.

It is fairly common for tornadoes to loft debris. This image is commonplace.

But, the image below, which appears to depict rotating debris aloft (it was Tilt 2) is unusual.

This is just a little of what was unusual about this storm. Researchers? Have at it!!

Thank You, Dr. Roger Pielke, Sr.

I was pleased to see this as part of my Twitter feed yesterday.
If you would like to check out my book Warnings: The True Story of How Science Tamed the Weather, click here.

Validation of My Forecast

I validate all of my severe weather forecasts for my readers as a way of holding myself accountable. I'm happy to report that yesterday's was a real stinker.

I use the word happy because tornadoes did not occur where forecast and fewer tornadoes are always a good thing. Below is the forecast posted here yesterday.

Below is the map of actual tornado reports (red dots = tornado).
I take my forecasting seriously and I'll do my best to do better next time.

Today's Tornado Risk

The brown area (5%) is the significant tornado risk threshold. The yellow is an enhanced risk and the hatching indicates strong tornadoes are possible. This includes Jackson, Hattiesburg, Gulfport, Mobile, Montgomery and Panama City.

Please monitor the weather in these locations today.

Wednesday, April 17, 2019

Damaging Winds Are Forecast

Above radar at 8:14pm CDT.

The NWS SPC is forecasting that an area of damaging winds will form near the KS-OK border near I-35 and move east. This should began around 9pm with the threat ending by around midnight.

This will be last update for the Kansas-Oklahoma severe thunderstorm threat.

Update 8:30pm. No sooner did I post this than the storms rapidly began organizing. Below is the radar at 8:25pm. Especially in the northern two rows of Oklahoma counties a band of damaging winds is forming rapidly. Gusts of 65-70 mph may occur in spots. There could be power failures. 

Severe Thunderstorm Watch For Southern Kansas and Northern Oklahoma

Good move by the Air Force to protect to protect their very expensive taxpayer-paid aircraft. Full article here.

Just a few minutes ago, the National Weather Service issued a severe thunderstorm watch for large hail and for strong wind gusts up to 70 mph. I'm not particularly worried about tornadoes.
Please put your car in the garage and bring in law furniture or other items that could be damaged by hail or high winds.

UPDATE: At least 1" hail reported at or very near McConnell AFB. Their decision to move the aircraft was proactive weather risk mitigation at its very best.

Weather Forecast Snapshot

Here is an experimental snapshot of the location of thunderstorms and the risks they pose for the period 6pm to 8pm. Please note the locations are approximate.
Please keep up on the weather in these areas. 

Two Day Tornado and Severe Thunderstorm Forecast

Forecast For Late This Afternoon and Tonight

The overall risk of tornadoes is low (but not zero) north of the Red River. From the Red River counties of Oklahoma south into Texas, there is a good chance of a few tornadoes, with the
better chance from sunset on during the night.

Unfortunately, hail may be the big event late this afternoon and tonight.
The hatched areas (including Wichita and the DFW Metroplex) are where large, damaging hail may fall.

Tornado Threat Thursday

This is the day where there is a serious tornado threat if things come together as forecast.
Where the hatching is located, there is an enhanced risk of tornadoes and damaging thunderstorm winds. I will update this forecast tomorrow morning.

Oops, Forgot to 'Look Out the Window'

Early in their careers, television meteorologists are told to always look out the window right before presenting a weathercast. It can prevent embarrassment.

Unfortunately, the American Meteorological Society (AMS) metaphorically forgot to look out the window before publishing this tweet yesterday afternoon.
There's only one problem: the drought ("80% accuracy"!!) has ended.

Here is a map of the Colorado River's watershed.
Below is a map of the current drought situation. The Colorado River is on the base map. Almost none of the Colorado River's drainage area, except northwest New Mexico, is in drought.

The other generally accepted drought index shows above normal moisture conditions over much of the basin. The only drought is over a small portion of western New Mexico.
Most of the Upper Colorado watershed in Colorado has above average snow cover, a full 30% above average.
So, this is a case of the AMS organization crying wolf. When it incorrectly cries wolf, it makes the entire field look bad. 

There is a second lesson here. This paper that formed the basis of the tweet was submitted to the AMS in its final form on October 31. What does it say about those in the field of climate study and their ability to make 60-year forecasts if science cannot make accurate forecasts six months out?