Last Update for the Night

Here is the AccuWeather regional radar for 9:24pm CST:

And, here is the forecast radar at 3am:

click to enlarge

This will be my last update of the night. I expect to do a storm update tomorrow morning.

Please come back to the blog around 9am for a very important report about storm siren policy.

Latest Weather Update

The high-resolution model from the National Weather Service shows 8 to 12″ of snow by Colorado sunrise (6am MST):

The swipe from Lubbock to Wichita that shows up as snow is the model sensing hail. Yes, there could be hail overnight. Below is the forecast radar for 1am CDT:

The current (7:30pm CST) AccuWeather winterized regional radar shows thunderstorms developing in the Texas Panhandle that could cause large hail overnight as they move northeast.

 The strongest storms right now are the ones just west of Amarillo.

UPDATE: 7:40PM. National Weather Service has issued a severe thunderstorm watch for large hail and damaging winds until 3am. 

4:20pm Storm Update

Here are the latest (4:15pm) watches and warnings from the NWS:

Orange = blizzard warning. Pink = winter storm warning. Deep turquoise = winter storm watch. Purple = winter weather advisory.

AccuWeather Regional radar at 4:19 shows the storm just getting started (radar is winterized).

click to enlarge any graphic

Here is the updated forecast (non-winterized) radar valid at 10pm this evening:

Strong thunderstorms are forecast to be occurring in the Oklahoma and Texas Panhandles at this time. Snow, often heavy, is predicted to be falling in Colorado.

The Storm Begins

Here are experimental radar forecasts that show the development of the winter storm and the potential thunderstorms.

The graphic below is valid at 6pm CST:

The forecast below (courtesy of the NWS) is valid at 10pm this evening:

The above forecasts do not differentiate rain versus snow. From a separate forecast model (hat tip: Dr. Ryan Maue) is the rain versus snow for 6pm this evening:

11:59pm this evening:

6am Friday morning:

This set of graphics should give you a good idea of the timing of the storm.

While the snowfall forecast below still looks good, some preliminary guidance from the new model runs indicate more than a foot of snow may fall farther south in eastern Nebraska and far western Iowa from Grand Island to Lincoln to Omaha to Council Bluffs. While still preliminary, keep this in mind if traveling.

Tornado Watches Have Expired

AccuWeather regional radar shows the line of thunderstorms continues to move gradually east across Louisiana and Mississippi but the threat of tornadoes, according to the NWS, had ended. So, they allowed the watch to expire. Strong winds are still possible with some of the stronger storms as the move east the next few hours.

Last weather update of the night.

Thunderstorm Update

Here is the AccuWeather regional radar at 5:04pm CST. The storms are developing in Arkansas about where expected (see posting below). I’d estimate we’ll see the first warnings in the 6 to 6:30pm time frame as the upper atmospheric low catches up to the unstable air in the Mississippi Valley.

Tornadoes and very high winds are the main threats. Stay tuned.

Tornado Watch Atlanta and Northwest Georgia

Right now the airports with delays are LaGuardia and Newark with averages of 16 and 45 minutes, respectively. That will likely change as strong thunderstorms approach Atlanta. A tornado watch has been issued for the area:

Below is AccuWeather’s regional radar at 4pm EST. There is a small thunderstorm just north of the Atlanta airport with strong thunderstorms moving in from the west. Expect major delays when the storms move in.

Airline Crisis Survival Guide is here.

Lightning Can Be Just as Deadly in Winter

From AccuWeather, the white + symbols are the locations of cloud-to-ground lightning at 11am Central time. The darker colors are locations from the previous hour.

Raw lightning data from Vaisala

While people are not outdoors as often, the lightning itself is just as deadly in winter as it is in summer. Prepared accordingly when thunderstorms approach. 

Severe Weather Threat Northeast and Midwest

A slight risk of thunderstorms with hail ≥1″ or winds of 60 mph or more in the yellow areas. There is also a slight chance of tornado in the NJ-Mass forecast area.

AccuWeather regional radar at 1:47pm EDT shows scattered thunderstorms across the region. These are expected to intensify during the afternoon.

At 2pm EDT, flight delays of 30 min. or more are reported at Newark, JFK, LaGuardia, and Philadelphia.

Flying Over Earth at Night, With Thunderstorms

Amazing video from the International Space Station of flying over the earth at night taken with a low-light HD sensor (select HD at the bottom of the YouTube frame).

My favorite part is the thunderstorms which begin about 20 seconds in.

The video ends when daylight begins.

Hat tip: WattsUpWithThat

Severe Thunderstorm Watch, New York and Vermont

Normally, I don’t cover severe thunderstorm watches. However, given the number of people working outdoors (power restoration, rebuilding roads, etc.) after Irene, I thought it was important to do so.

The watch also includes parts of Pennsylvania, but this area was not affected by Irene.

Remember, a severe thunderstorm watch means that winds of 60 mph or more and hail ≥1″ may occur with the thunderstorms. These storms may also cause heavy rain and frequent cloud-to-ground lightning.

Please monitor local weather and make sure you are indoors when a thunderstorm approaches.

Thunder Trifecta Today

Third thunderstorm of the day at The Smith House. Very nice lighting of the rain curtain as the rain moved in. Photo taken 4 minutes ago.

UPDATE: Wichita’s Mid-Continent Airport recorded a 50 mph wind gust with this storm.

Nate Johnson on Weather and Smartphones

Nate is the impressive weather producer for WRAL TV in Raleigh. His blog posting here. Nate talks about pilots, weather, and smartphones. I’d like to relay an experience of my own from just last week.

There were thunderstorms occurring around Wichita’s Mid-Continent Airport and I noted the captain looking at his smartphone at the gate. I asked which program he was using for radar. I knew it was one that had a built-in delay of 5 to 7 minutes which could be critical in a thunderstorm situation. I also gave him some additional apps that might be helpful. While I’m not fully comfortable with flight crews using smartphones for radar, if they are going to use it, the radar should be as timely and detailed as possible. 

As we taxied out, I could see cloud-to-ground lightning striking the ground. It was one of the few times I have been nervous before a take-off. We got into position at the end of the runway, paused a few minutes (yes, minutes)… and pulled off the runway. It was an hour and forty minutes before we took off, which was exactly the right thing to do.

To what extent my suggestions might have assisted, I don’t know. But, I thanked the crew for a great job when we landed in Houston and they seemed appreciative.

Damaging Wind Threat

I try not to make this too much of Plains-centric blog but there is a fairly high chance of a thunderstorm event with damaging winds and large hail, especially in the hatched area later today and tonight.

NWS forecast

The experimental radar forecast shows the storms just starting to develop in central and western Kansas around 4pm and moving rapidly east or southeast after that time (don’t take this forecast too literally). It is a good idea to bring in lawn chairs, the kids’ trampoline and put the car in the garage.

If You are Traveling By Air Today…

Note that there is a pretty good chance of thunderstorms around Atlanta and a lesser chance around Chicago, Cleveland, and NYC. LaGuardia already has 15 minute delays as does Washington Reagan. You might want to see if you can get an earlier flight if you are traveling to or changing planes in these areas.