Sunday, September 26, 2010

Yucatan Region Remains Active

The above composite image of the Tropical Atlantic shows Tropical Depression Lisa over the far East and Tropical Depression Matthew decaying over Central America (while dumping massive amounts of rain).

The yellow encircled area to the immediate right of Matthew indicates the location of a tropical disturbance developing off of the Yucatan Peninsula.  This area of development has been hinted-at by computer forecast models for nearly a week now.  At the time it first appeared on the forecast models it was hard to tell whether the system would be the result of the remnants of Matthew, or a newly formed storm.  At this time, things are obviously starting with a newly formed circulation to the Southeast of the Yucatan, however the computer forecast models still hint that the two may merge at some point early this week.

Below is the Global Forecast System (GFS) model forecast valid at 7pm Central Daylight Time (CDT) this evening.  I have encircled Matthew in purple over Central America (in the bottom left corner of the image):

Below is an image from the same forecast model valid at 7am CDT on Tuesday.  Note that within the area encircled in purple we have what appears to be the remnants of Matthew about to merge with the newly forming tropical disturbance off the Yucatan Peninsula: 

The next image below is the same forecast model, this time valid at 7pm CDT on Thursday evening.  By this time, the Matthew/Yucatan combination system has moved North/Northeast into the southeast U.S. (being drawn into a rapidly moving trough of low pressure), again noted by the purple encircled region.  Meanwhile, yet another system is forecast to be developing off of the Yucatan Peninsula, this time noted by the red encircled region:

By 7pm CDT on Sunday (October 3rd), an area of disturbed weather (presumably the same disturbance noted above) off of the Yucatan Peninsula (again encircled in red) is gaining strength and beginning to lift North/Northeast toward Western Cuba:

Needless to say, the region off of the immediate coast of the Yucatan Peninsula has been a hotbed of activity this season, and the next week to 10 days promises a continuation of that trend.  Below is an image from "Google Earth" showing Tropical Storm & Hurricane formation points during the month of October from 1851 to 2007.  You can see that this "hotspot" off of the Yucatan Peninsula typically remains active into the final month of the "official" hurricane season each year:  

Wednesday, September 22, 2010

Happy Autumn!

Today is the first day of fall/autumn in the Northern Hemisphere.  This will be signified by the Autumnal Equinox, which takes place later this evening and tonight.  This is a scientific term used to describe the process where the Earth's axis is tilted away from the sun for a longer period of time.  This results in longer nights and shorter days as we progress through winter, as well as gradually cooler temperatures as the sun bakes us for shorter periods of time each day (as shown in the image below).

So what does the fall and winter season look like for this year?  Below are the latest forecast maps showing the outlook from the National Weather Service:

In general, "above normal" temperatures are forecast from the southwest and southcentral U.S. into the Great Lakes region.  "Below normal" temperatures are forecast along the Pacific Coast.  Precipitation-wise, "below normal" values are forecast across the southern tier of states, with "above normal" rainfall forecast for the Pacific Northwest.

The above maps cover the period October-December.  We'll continue to monitor long-term trends and post updates throughout the season.

Sunday, September 19, 2010

Igor Pounding Bermuda

The above radar image, taken just a few moments ago from the island of Bermuda, shows the center of Hurricane Igor about 110 miles to the South/Southwest and moving North at 16 mph.

Maximum sustained winds are estimated at 85 mph.  Tropical storm force winds, with gusts over hurricane force, have been taking place on Bermuda for the past several hours.  Sustained winds of hurricane force can be expected by this evening. is posting videos to YouTube showing conditions on various parts of the island.  You can go to their YouTube page here.

Hurricane Igor Moving Closer to Bermuda

The above satellite image shows Hurricane Igor moving toward Bermuda this morning.  At 7am CDT, the center of Igor was located 190 miles South of Bermuda...and moving North at 13 mph.  Maximum sustained winds were 85 mph.  

Below is a radar image taken a few moments ago from the Bermuda radar.  You can see the eye of Igor advancing toward the lower left corner of the image:

Heavy squalls with tropical storm force winds are already battering the island early this morning.  The picture below was taken by Bermuda News just a few moments ago and shared via Twitter:

Hurricane force winds can be expected by this afternoon.  Very heavy surf and storm surge will cause significant coastal flooding as well.

Late tonight into early Monday morning...Igor will turn more toward the Northeast and move out to sea.  He is not currently forecast to directly affect any landmasses again until perhaps reaching the outskirts of the Canadian Maritimes by mid week.

Saturday, September 18, 2010

Tropics Remain Active...

The remnants of Karl are spinning over southern Mexico this morning, spreading copious amounts of heavy rains over that mountainous region.  Widespread flooding and mudslides are likely to continue in that region today.

Meanwhile, further North, the combination of a trough of low pressure at the surface along the Gulf Coast and a weak upper level disturbance moving over the region today will result in widespread shower & thunderstorm activity for much of South Texas.  The heaviest, most widespread precipitation is expected to take place along the coastal regions from Corpus Christi on southward.  

Additional, more widely scattered, activity will take place into portions of Central Texas along the I-35 corridor later this afternoon (much like what took place on Friday).

Back to the satellite image at the top of the post, you can see hurricane Igor out over the central Atlantic, heading toward Bermuda.  The system is expected to impact Bermuda later tonight and Sunday.  

Maximum sustained winds are currently 110 mph...and Igor is expected to remain a dangerous hurricane as it impacts Bermuda over the 2nd half of the weekend.  Below is the latest closeup image of Igor:

Friday, September 17, 2010

Karl Now a Major Hurricane - About to Make Landfall

At 7am CDT this morning...the center of Hurricane Karl was located 50 miles Northeast of Veracruz, Mexico...and moving West at 9 mph.

In yesterday morning's post...we mentioned that Karl had intensified rapidly upon moving back into the Gulf from the Yucatan Peninsula the day before.  That strengthening continued yesterday, and Karl is currently packing winds of 120 mph, which makes him a "major" hurricane.

Karl will make landfall later this morning along the lower Mexican coast.

Thursday, September 16, 2010

Karl Emerges Into the Gulf

As expected, Tropical Storm Karl has emerged back out over open waters early this morning - this time in the far southwest Gulf of Mexico.

At 7am CDT...the center of Karl was located 110 miles West of Campeche, Mexico.  Karl was moving West/Northwest at 9 mph...with maximum sustained winds of 65 mph.

Karl has reintensified rather rapidly for having only moved off of the Yucatan Peninsula a matter of hours ago.  He is likely to become a hurricane later this morning, and will make landfall for a final time tomorrow afternoon along the lower Mexican coast.

This track is further South than originally forecast by computer models earlier this week.  This would tend to limit the prospects for any precipitation associated with Karl across the southern U.S. over the weekend.

Wednesday, September 15, 2010

Tornadic Storm in South-Central Kansas

The above image shows a tornadic thunderstorm in southcentral Kansas just a few moments ago.  The storm was centered Northeast of Winfield and West of Burden.  Note the "classic" hook echo configuration to the Northeast of Winfield.  Numerous funnel clouds and at least brief tornado touch-downs have been reported with this storm so far.

The above image shows "reflectivity" from the radar, in other words, rain and hail being reflected back by the radar beam.  The image below shows the same radar but in "velocity" mode, which shows the wind movement toward and away from the radar.

Note the same storm Northeast of Winfield.  The reds and yellows show wind blowing away from the radar (located in the upper left corner of the image) while the greens and blues show wind blowing toward the same radar site.  This indicates strong rotation, as annotated by the arrows in the image below:

Tuesday, September 14, 2010

From Nothing to Karl

The area of disturbed weather over the northwest Carribean Sea went from just that... an area of disturbed weather... to Tropical Storm Karl, in a little under 12 hours today.

At 4pm CDT...the center of Karl was located about 270 miles East of Chetumal, Mexico.  Movement was West/Northwest at about 15 mph.  Maximum sustained winds were estimated at 40 mph.  Some additional strengthening is possible overinight as the system approaches the Yucatan Peninsula.  

Karl is expected to make landfall on the Yucatan tomorrow afternoon.  It will then emerge back out in the open waters of the southwest Gulf of Mexico early on Thursday.  A second landfall along the middle coast of Mexico is then expected late Friday or early Saturday.

Sunday, September 12, 2010

The Hurricane With the Unfortunate Name Grows Stronger

No offense to any readers by the same name (and if you're out there, please send me an e-mail - I think it would be awesome to receive an e-mail from someone by that name), but I have no idea why "Igor" would end up on the hurricane name list.  Everytime I hear it, I picture a hunch-backed assistant helping the mad scientist in his lab.  Oh well, enough of the editorial and potentially insulting comments...

While the name may be funny...Hurricane Igor is no laughing matter.  As of the 4pm CDT advisory, the storm has intensified to a dangerous category 4 hurricane.  The center of the storm is located approximately 1065 miles East of the Northernmost Leeward Islands...and moving West at 14 mph.

Maximum sustained winds have increased to near 140 mph...and some additional strengthening is forecast over the next few days as the system moves out over even warmer waters.

Residents of Bermuda beware...Igor could threaten you in 5-7 days.

Thursday, September 9, 2010

Tropical Twisters Strike Dallas Area

The above image, captured by a viewer and passed on to WFAA-TV in Dallas, shows a tornado crossing the Trinity River in Dallas yesterday evening. 

This was just one of several brief touchdowns associated with the remnants of Hermine as it crossed northcentral Texas yesterday.

Tornadoes associated with tropical systems are typically weak and short lived, however just like everything else, those are relative terms.  If a weak, short lived tornado touches down in a field in a rural area, no harm done.  If, however, that same tornado touches down one or more times in a heavily populated area, the result is what happened in Dallas yesterday:

Fortunately, no serious injuries or deaths were reported.  This is remarkable, particularly in that most of the activity took place between 5 and 6:30 pm, right during the middle of the evening rush hour!

Wednesday, September 8, 2010

Heavy Rains From Hermine Spreading Northward

Widespread, heavy rains associated with Tropical Depression  Hermine continue to spread North out of Texas and into Oklahoma late this afternoon.  The above image was taken from the Oklahoma City radar just a few minutes ago.  Below is an image from the same radar, this time showing the radar's estimation of total rainfall so far today:

As you can see, widespread amounts of 3-5 inches are indicated across much of extreme northcentral Texas into southcentral & southeastern Oklahoma.  

This activity will continue spreading Northward across Oklahoma this evening and into parts of Arkansas, Kansas and Missouri overnight.  Below is the latest rainfall forecast for tonight into Thursday:

Tuesday, September 7, 2010

Hermine Summary - So Far

The images above and below show the latest position of Tropical Storm Hermine, which is currently located just Northwest of Fredericksburg, TX.  The above image shows the radar perspective from the New Braunfels, TX radar site.  The image below shows a visible satellite image perspective (from outer space, no less).

Hermine is still not through with the Lone Star State...but has already left a mark or two.  The images below show significant storm reports so far since landfall.  First image is from southcentral Texas, with a few of the more notable reports highlighted on the left hand side of the image (click to enlarge):

The second image highlights reports from central Texas so far today:

Not really addressed by the above images is the widespread, heavy rainfall.  Here at my house near Kyle we have measured 3.03 inches so far today, and it's still raining moderately at this time.  We need every drop we can get, and fortunately the rains in our area fell in such a way as to not cause any major problems (other than a few of the unavoidable fender benders, etc.)

Other parts of the state, particularly further South and East, haven't been so lucky.  While the rains were much needed there as well...they fell even heavier, and in a shorter time period.  Below is the doppler radar estimation of total rainfall so far in association with Hermine.  The site is again from New Braunfels, TX (click to enlarge):

The brightest pink and purple areas (most widespread near the coast) indicate total rainfall estimates of 6 to 8 inches.  The red shaded areas indicate rainfall of 3-4 inches.  The orange and yellow areas correspond to estimates of 1.5 to 3 inches.

Below is the same information, except as presented by the Corpus Christi radar site:

...and the Brownsville radar site (where the white shaded areas indicate rainfall estimates of greater than 10 inches, mostly over water):

Hermine continues on North/Northwestward this evening as a Tropical Storm, even some 200 miles from the coast!  Further weakening, at least insofar as the winds are concerned, is likely this evening and overnight, but the heavy rainfall threat is far from over.  Below is the latest forecast of rainfall potential for Oklahoma, Kansas and Missouri through tomorrow, where the rains have yet to begin in earnest:

Hermine Still Holding on - Dumping Lots of Rain

The above image of Tropical Storm Hermine as seen by the New Braunfels, TX radar was taken just about 5 minutes ago, and shows the center of the storm just Northwest of San Antonio.  Movement is North/Northwest at 20 mph.

As the inner core (surrounding the center) traversed San Antonio over the last hour, several reports of wind gusts in the 40-50 mph range were received...along with a continuation of the very heavy rainfall.

The image below shows storm total rainfall estimates as viewed by the same radar, through about 1:45 local time.

The brighest pinks and purples near the coast in Southeast Texas show radar estimated rainfall of 6-8 inches.  A large area of the orange and red shading extends well back Northwest to the Austin/San Antonio corridor, where radar is estimating that 3-6 inches of rain has fallen.

Going back to the top image showing the most recent radar, you can see that the continuous, heavy rains are about to come to an end from South to North across the corridor from San Antonio to Austin, as the center of Hermine continues North/Northwest.  There are still additional "feeder" bands of lighter showers redeveloping to the Southeast, which will traverse the region throughout the remainder of the afternoon and into this evening.  These bands could produce up to another inch of rain through this evening, with localized amounts near 2 inches possible in some of the heavier showers.

Heavier Rains Spreading Across I-35 Corridor

The above image was taken from the New Braunfels, TX radar about 7 minutes ago.  You can see the center of Tropical Storm Hermine located just Southwest of George West, TX.  Hermine is moving North/Northwest at 15 mph.

Heavier rainfall rates of up to 1 inch per hour are now spreading into the I-35 corridor region from San Antonio to Austin.  The image below shows the 1-hour rainfall rate as estimated by the same radar:

I have zoomed in on the image so that you can see the greater Austin area.  The darker green and yellow areas to the Southeast of Austin show areas of 0.75 to 1.5 inch rainfall rates per hour.  These heavier rainfall rates will continue spreading Northwest into the Austin area over the next 2-3 hours.  This will result in an increased urban and small stream flooding risk in the metropolitan area. This will primary affect areas from the Kyle/Buda area on North into Austin.

Another area of enchanced rainfall rates will move into the San Antonio area from the Southeast this morning, in association with the center of Hermine and an band of locally heavier rain surrounding that center.

If you live or have to travel through flood-proned areas along the I-35 corridor from San Antonio to Austin, use extreme caution.

Hermine Inland...Still a Tropical Storm for Now

The above image from the New Braunfels, TX radar was taken about 5 minutes ago.  The center of Hermine was located about 35 miles Southwest of Mathis, and was moving North Northwest at 17 mph.  Maximum sustained winds remain at about 45 mph.  Now that Hermine is mostly inland, weakening of the winds will take place today, but heavy rains will continue.

The latest forecast of total rainfall for today shows a widespread swath of 4-6 inch rains for much of southcentral through central Texas.  Localized amounts of 6-10 inches will be possible.  This will eventually spread Northward into Northwest Texas later today and tonight.

On Wednesday, heavy rains will spread Northward into Oklahoma...