That's Right, Toto - We're Not in Kansas Anymore!

The above image is of the Portland, Maine (yes, I said Maine) radar (KGYX) about an hour ago.  Look at the structure on that rotating storm between Mechanic Falls and Greene!  


Below is a shot from the same time, in Storm Relative Velocity mode (greens and blues are wind blowing toward the radar; reds and oranges are winds blowing away from the radar).  The radar site is located just off the bottom-center of the screen.

What a rare treat for severe weather enthusiasts in the far Northeast.  Several funnel cloud reports were received, but I have not yet seen any ground-truth tornado reports.  I'll post them later on if I find any...

Yes, Tornadoes Can Develop In New England, Too...

I can't remember the last time the Boston area was under a Tornado Watch (I'm not saying it's been years or anything like that, and I know I could find the date if I really wanted to dig for it, but I'm just not in the mood to dust-off the archives right now).  Anyway, wouldn't you know it, the Boston (KBOX) doppler radar is down this afternoon (I'm sure George W. Bush is somehow at fault here, but that's really not important right now).  Parts are "on order" and the last status message said that the NWS hopes to have it online by 7 o'clock this evening (central time).


(I digress slightly, but if you ever notice that your local radar seems to be showing old imagery - or no imagery at all - and want to see what the heck is going on, visit the NEXRAD Status Page for more info. than you probably want to know on the subject).


So, what is a guy (or gal) to do when an interesting storm is developing in the KBOX warning area but the radar isn't available?  Well...go South to Long Island, of course.  A cell that just moved through Windsor-Locks, CT looks pretty nasty and is trying to get better organized.  Here are a few images from the KOKX radar in Upton, NY (on Long Island):

Reflectivity (precipitation echoes)

Vertically Integrated Liquid (VIL) - Hail Anyone?

VIL image with Hail Algorithm & Data Table

The first image is pretty obvious, the reflectivity data (rain, hail, etc.) from the Upton radar site.  The last 2 are Vertically Integrated Liquid (VIL) displays of the same storm.  As I've blogged about in the past, VIL can (among other things) give you a rough idea as to hail potential, partcularly in large/well organized and/or severe storms.  The white areas on this particular VIL image correspond with the highest values on the scale (77 kilograms per square meter to be exact - in this case).  

NEXRAD's (the doppler radars that are used to obtain the above images) don't just produce pretty images of various kinds of weather information.  The computer programs that drive the units also derive other kinds of data, via algorithms that are programmed into the system.   For example, on the last image, I have overlaid the hail algorithm output (note the green triangle East/Northeast of Rockville).  That particular triangle denotes what the radar believes is the potential for hail up to 1" in diameter falling at or near that location.

If you click on the image to enlarge it, then look at the data table (a.k.a. "Storm Attributes Table") that is overlaid in the upper right hand portion of the screen, you'll find other information as well.  The particular storm we've been looking at has been labelled "Q8" by the computer program.  Upon further examination of the data table, you'll see that the computer is forecasting a 50% chance of severe hail (POSH) and a 90% chance of hail (POH) with that storm.  The maximum expected hailstone diameter is noted under the "Size" column, in this case 1.00 inch.

GRLevel3 users know to select "Show Storm Attributes Table" from the "Windows" menu of the program in order to display the above table.

I'll provide additional information on what some of the other data included in the table means in another post...

If It Looks Like a Hurricane Right Over Texas, It Must Be an MCV

Nice post on the CIMMS Satellite Blog regarding the Mesoscale Convective Vortex (MCV) that moved across much of Texas day before yesterday.


It may not look much like a hurricane on the above image, but go to the CIMMS blog posting and watch the loop - it gets better organized with time.

Thunderstorm Complex Continues Southeast into Coastal Plains

Above is a radar image (reflectivity mode which shows precipitation echoes) from the New Braunfels radar (KEWX) taken shortly after 9:30 pm this evening.

The thunderstorm complex that originated west of the Hill Country earlier this afternoon has since rolled through the I-35 corridor and is now advancing Southeast at 40 mph toward the coast.  It will soon merge with another thunderstorm cluster moving East from Mexico (currently across McMullen and Duval counties).  Gusty winds of 40-50 mph have continued out ahead of the leading edge of the main complex, and an occasional small hail report has also been received over the past hour.  The main "show" with this complex is currently heavy rain, gusty winds and frequent lightning.

The lightning show here where I live (near Kyle, TX) has been spectacular ever since storms first started approaching shortly after 7pm this evening.  We also recorded wind gusts of 46 knots (53 mph) when the gust front moved through around 7:30 pm.  So far, about 1.4 inches of much needed rain has fallen.

Thunderstorm complexes such as the one that formed this evening are really the only source of widespread rainfall for much of central and east Texas during the summer months (other than the much less frequent landfalling hurricane or other tropical system).

Thunderstorm Update for I-35 Corridor - Austin to San Antonio

The thunderstorm complex that I blogged about earlier this evening continues to advance Southeast toward the I-35 corridor.


Here is the latest reflectivity (precipitation echo) image:

Note the thin blue line advancing Southeast of the complex, about halfway between the leading edge of the thunderstorms ad the I-35 corridor.  That is called a "gust front" and in this case indicates wind gusts of 40-50 mph blowing out ahead of the main thunderstorm complex.

This activity is currently on a track to impact the I-35 corridor from Austin to San Antonio over the next hour.  During the past 45 minutes, the hail signatures have decreased with this activity, but marble size hail is still possible, along with gusty winds, frequent lightning and very heavy rain.

Thunderstorm Complex Heading Toward I-35 Corridor

A complex of thunderstorms continues to develop over the Hill Country, and on current track would impact the I-35 corridor from San Antonio to Georgetown between 7 and 8pm.  If the storms speed-up, they could arrive even earlier, though so far they are not tending to do so


The image below is of the New Braunfels (KEWX) reflectivity (precipitation echoes) from just a moment ago:

As you can see, very heavy rainfall is widespread along the leading edge of the complex, with moderate to light rains following behind.  Hail and gusty winds are also possible with the leading edge of the complex.  The image below is Vertically Integrated Liquid (VIL) taken at about the same time from the same radar.  VIL roughly corresponds with hail potential.  The white areas on the VIL image indicate the highest potential for hail in those areas, roughly the size of golfballs at this time:

Folks living along the I-35 corridor from San Antonio through Austin and Georgetown should remain alert this evening for possible severe weather.

Dude, That's a Huge Rock!

What's a meteorologically challenged family to do on Memorial Day Weekend?  Climb the 2nd largest rock formation in the country?  Sure, why the heck not.


Below is a view from the parking lot (yes, I said parking lot - how primitive do you think we are here in Texas, anyway???) of the Enchanted Rock State Park near Llano, TX:

I'm sure this seems a rather elementary event to an experienced climber, but when you live on the relatively flat plains of south-central Texas, hey, this counts for something.  Plus, this is one big rock, folks.

I was actually amazed at the scenery as we climbed the formation.  The pictures certainly don't do it justice, but here goes:

And if the picturesque views of the Texas Hill Country from atop the "pink granite exfoliation dome" (I think I like "damn big rock" better) weren't enough, we were also treated to some awesome displays of wildflower magic on the route to and from the park:

So, if you're ever stormchasing in central Texas (why you'd be doing that, I have no idea) and you find yourself "capped-out", take a ride about 17 miles North of Fredericksburg and treat yourself to some scenic wonders, Texas Hill Country-style.