Dr. Jeff Masters' WunderBlog

Michael...cool link showing the effect. Have to look into this more...

Take a look at the water vapor loop, and the exploding convection. That's heading for DC area in a few hours. Dubya better hunker down!!

http://www.goes.noaa.gov/HURRLOOPS/huwvloop.html

Ok..found an article Link that I think is interesting. Going to the bottom, it decribes urban heat islands and how it could affect boundary-levels.

"Example: the urban boundary layer. Cities exert their own influence on the boundary layer. The Earth-atmosphere interface in a city tends to be drier and rougher than areas of open land. In addition, the nature of man-made building materials means that they tend to respond rapidly to solar heating (G and c). Since the surface is dry, the latent heat flux into the air is small, so energy passes into the boundary layer in the form of sensible heat. This creates the `urban heat island' effect: the city tends to be warmer than the surrounding rural areas. Under low winds, a circulation similar to the sea breeze results, during the day, with cool air entering the city. This may cause pollution to converge on the city region. Under stronger winds, the high roughness length of the urban area causes relatively strong drag, leading to a deflection of the winds to the left (northern hemisphere). Generation of turbulence by the roughness tends to keep the boundary layer well-mixed, which means that a nocturnal inversion, with cold surface temperatures, is less likely to occur in an urban area."

If this is true, and the urban heat island could by the resulting turbulance in a city cause the boundary layer to be well mixed..doesn't that promote the capping effect that could restrict storms from building?

If I am crazy..let me know.

Well, I am now on the borderline of the slight risk and moderate risk.

Nashville is under a tornado warning.

Oh no Geeze is in DC today.....

Look at the tornado probability.

Link

How do you post pictures?

The heat island effect isn't the best example of what will happen when the earth is warmer, since the result is from the temp difference inside & outside the city that causes the instability. Also a heat island effect depends on the surronding enviroment. As Melbourne has been paved & built over, I've watched the effect. Many times when a stiff wind from the east off the ocean is creating our sea breeze showers, the heat island effect inhibits the rain in Melbourne but bring violent storms to the North & south of us. You can watch the clouds blow in & up, splitting in the middle over the city sending a spiral of cloud both north & south of here.

I was afraid today the storms would be worse, now that the low's tail is drawing from the gulf.

Hope this works.

Good, it worked.

Anyway, as you can see it shouldn't be so bad tomorrow.

Sky...question...you said "You can watch the clouds blow in & up, splitting in the middle over the city sending a spiral of cloud both north & south of here."

What would cause that split? Heat island? If so..why?

On a side note, looks like next week could bring more flooding to California's Central Valley too. Southern California will probably also get some rain but compared to last year the flooding should be minor. (that isnt saying much though)

Yes, the heat island thing works much the same way as storms move across Atlanta area, but usually from the opposite direction as melbourne. Convection is usually moving west to east around Atlanta.

Wow the south is getting pounded tonight Wab...good thing you didn't get this yesterday....we got a good soaker today...little rumble of thunder but just a nice storm over all...nice to wake up to and drink coffee to...:)

opppsss wrong blog.....dang it....

It's looking like a long night in Huntsville, AL. Of course, the lightning show has been incredibly impressive.

Looks like it will be a long night. They are throwing up tornado watches here in NC. The storms are starting to push towards western NC. If you have access to a lightning tracker, the map is quite impressive. Just a wall of lightning hits from Louisiana all the way into VA. A seconday line from Kentucky into PA.

Any of you in Huntsville. I'm watching and hoping family memebers are ok.

that is the cool part of the t-storm at night is the lighting show

Hurricane Irene was a Cape Verde storm, and TD 19 formed near the Cape Verde Islands.

It can be found here StSimon...

Severe Weather Outlook

I just opened my window, and I swear the temperature in my room dropped at least 15 degrees.

It was pretty hot in here, so I am very happy.

The line of storms moving into western NC from eastern TN looks to be weakening somewhat. There is less lightning, and the radar returns are diminishing somewhat.

Sayhuh~ I can only speculate from what I've observed as the heat island here has formed & the enviroment that has changed. Before the rampit developement the initial sea breeze developed evenly along the coast, light showers to thunderstorms coming inland parrallel to the coast, somedays it meets with the west coast sea breeze, usally causing thunderstorms or worse. That line can pile up along east coast, west coast or many times in the middle than move back east, west or pound the interior, depending which coast sent the stronger winds.

Once Melbourne was built up, as the seabreeze rolled by (ussually in the mid to late morning), it would have a gap over our developing heat island. I'm not sure but I think Lake Washington (just west of Melb), St Johns river & a lot of swamp to the west plays a roll ~ stong east wind hits extra heat (from the heat island), the clouds rise, then hits the cooler air like a wall perhaps. They do circle back around as they rise. To the south, the clouds curve S back to E, N & W again, just exploding many times before the whole line moved west. The N side of me would do the same thing but spin clockwise while building. We'd get warm wind, sometime blue sky right over head & maybe a little rain.

As the years went by new areas were built N of here, Suntree & Viera. Those areas stopped taking such a beating. Just north of there Cocoa, Rockledge & Titusville have been for a long time & had grown as well. The gap got wider as Mims, just north of Titusville & still rural, now takes a much larger brunt on a regular basis. To the south as Palm Bay has grown they are taking a little less beating (their not quite to the heat island standards of developement obtained here). The brunt has move to the next rural town south, Malabar.

On days that the clash happens with the west coast breeze & moves back this way, if we had no rain earlier, which many times now it the case, we get a beating many times since it's become so hot by late afternoon.

The storms seem to be calming a little, no tornado reports in nearly the last 2 hours...

The hail is raging on though in mostly AL. Not 45 mins ago 4 1/4" hail in Marshall county AL.

4 1/4 inch hail...........is that big?

600 severe weather reports.

I'd say that's at least baseball size, probably larger. And yes, that's big.

I know that it is big. I was being sarcastic.

The largest hail I have ever seen was probably midway between dime size and nickel size, and I am in no hurry to see anything larger.

yeah i was once caught out in marble sized hail and that is enough for me. i can't even imagine softball size.

Good morning Dr Masters and Weather Folks.

Sure hope today is better than yesterday was as far as the sever thunderstorms, hail, and tornadoes go.

Four inch hail...that's a rock falling at terminal velocity. Ow.

Gonna be stormy for us later today:Weather Hazards for Chas SC