Watching the Skies » Unusual Weather

West Dallas tornado rated eF-2, six other tornadoes around north Texas

Sean Toner — Thu, 09 Sep 2010 22:59:39 +0000

Tornado damage consistent with an eF-2 tornado was found in West Dallas during a storm survey conducted by the National Weather Service today. The tornado’s path was one half mile in length, causing significant damage to numerous structures in that area. A preliminary track map shows it crossing the Trinity River and its levees, which should debunk any myths people may of had about tornadoes and river crossings… (source: http://www.srh.noaa.gov/fwd/?n=prelimtrackmap) I have included a tornado damage summary provided by the National Weather Service below.

Six other tornadoes were documented around the area, including another which caused moderate damage in southeast Dallas county, to the city of Seagoville. Below is radar snaps of the storm as it looked while producing the tornado in West Dallas. The storm is not overly impressive, when compared to supercells during our spring time severe weather season, but still displays the traditional hook echo and velocity couplet associated with tornadic supercells.

A similar feature is observed with the northeast Ellis/southeast Dallas counties tornado. A noteworthy hook echo and velocity couplet are observed by radar.

Thankfully the next 7 days don’t appear to show any significant tornado threats. Forecast models show marginal chances of thunderstorms Friday night, but I wouldn’t bet on it. Additionally a weak front may move through the area Saturday, then lay stationary across the Metroplex Sunday into Monday. This front has the potential to kick off organized severe development along and to the south of the front, but coverage of storms may be limited. Regardless I would consider storms a possibility Saturday and Sunday. Straight line winds and hail would be possible with stronger storms over the weekend, but the tornado threat will be minimal as environmental wind shearing will be very low. Temps the next 7 days will remain above normal and with high dew points due to the obvious abundance of moisture, our heat indexes will be around 100 to 105.

It would seem summer has not quite left us yet.

Tornado damage survey report by the NWS:

…PRELIMINARY DAMAGE REPORT…

A TOTAL OF SIX TORNADOES OCCURRED ON WEDNESDAY SEPTEMBER 8TH. FOUR
TORNADOES WERE RATED EF0 ON THE ENHANCED FUJITA SCALE. ONE TORNADO
WAS RATED EF1…AND ONE TORNADO WAS PRELIMINARILY RATED EF2. ONLY
TWO MINOR INJURIES HAVE BEEN REPORTED FROM ALL OF THESE STORMS.

THE EF2 TORNADO DAMAGE WAS LOCATED IN THE CITY OF DALLAS NEAR THE
INTERSECTION OF MOCKINGBIRD LANE AND IRVING BOULEVARD. THIS
TORNADO CAUSED MINOR ROOF DAMAGE TO SEVERAL BUILDINGS AND CAUSED
MORE EXTENSIVE DAMAGE TO A WAREHOUSE. AN EXTERIOR NON LOAD BEARING
WALL COLLAPSED…LEADING TO A PARTIAL COLLAPSE OF THE ROOF. THIS
DAMAGE WAS RATED EF2 ON THE ENHANCED FUJITA SCALE WITH WIND SPEEDS
OF APPROXIMATELY 115 MPH. THE LAST TIME THE CITY OF DALLAS HAD A
TORNADO RATED AT F2/EF2 OR HIGHER WAS F2 TORNADO DAMAGE ON APRIL
11 1974. THE LANCASTER TORNADO OF APRIL 25 1994 PRODUCED F4 DAMAGE
IN THE CITY OF LANCASTER BEFORE DISSIPATING WITHIN THE CITY LIMITS
OF DALLAS.

THE EF1 TORNADO DAMAGE WAS LOCATED IN THE CITY OF SEAGOVILLE JUST
EAST OF HIGHWAY 175. AT LEAST THREE APARTMENT BUILDINGS SUFFERED
SIGNIFICANT ROOF DAMAGE. WIND SPEEDS IN THIS TORNADO ARE ESTIMATED
TO BE NEAR 90 MPH.

THE REMAINING TORNADO DAMAGE WAS GIVEN A PRELIMINARY RATING OF
EF0. THESE TORNADOES OCCURRED NEAR LINDSAY IN COOKE COUNTY…NEAR
FERRIS IN ELLIS COUNTY…IN HEATH IN ROCKWALL COUNTY…AND NEAR
BLOSSOM IN LAMAR COUNTY.

THE ENHANCED FUJITA SCALE RATES TORNADO DAMAGE.

ENHANCED FUJITA SCALE APPROXIMATE WIND SPEED RANGE

EF0 65-85 MPH
EF1 86-110 MPH
EF2 111-135 MPH
EF3 136-165 MPH
EF4 166-200 MPH
EF5 200 MPH OR GREATER

Tropical Storm Hermine & it’s effects

Sean Toner — Thu, 09 Sep 2010 02:08:59 +0000

Tropical Storm Hermine, a remarkably impactful storm for the DFW Metroplex which sits 550 miles north of the storm’s initial landfall. The storm has brought severe flooding to a 300 mile stretch of central and north Texas, along the I-35 corridor. The worst flood effects are being felt in San Antonio through Austin. Flash flooding has even occurred in the Metroplex, the most notable being numerous homes and trailers flooded in the cities of Lewisville, Arlington, and Fort Worth. The heavy rains brought over 12 inches of rain near Austin as of 8am today (9/8/10) and 4 to 6 inches of rain in the Metroplex. (source: CoCoRaHS) My CoCoRaHS gauge captured 4.01 inches of rain in the 24hr period from 8am 9/7/10 to 8am 9/8/10. Another several inches have been observed since that time, with even more rain on the way. Below is radar estimated total rainfall from the FWS dopplar radar. An even more accurate and complete picture region wide view is available from the National Weather Service at http://www.srh.noaa.gov/ridge2/RFC_Precip/.

As if the flooding rainfalls weren’t enough, Hermine brought the risk of tornadoes to the region with several damage reports in Dallas, Highland Park, Seagoville, Ferris and Trumbull. Tornadoes embedded within the outer rain bands of tropical systems aren’t uncommon to coastal regions in the Gulf, but it is fairly unusual to get those type of tornadic storms this far away from the Gulf. Tornadoes in this type of environment tend to develop without warning and are difficult to detect with current radar technology, but are very brief and usually weak. The Dallas Morning News reported ripped up roofs in Cockrell Hill, Oak Cliff, West Dallas, and the Love Field areas. (source: Dallas Morning News) A Tornado Warning was also issued for a storm 4 miles south of Hebron at 5:37pm. The warned area included Frisco, Plano, and The Colony. The storm showed rotation on radar, and storm spotters observed a rotating wall cloud within the storm. Thankfully no tornado damage has been reported with this storm. Its center of circulation traveled north along the Denton/Collin county line, passing over Highway 121 and Plano Parkway, then dissipating. I got the pleasure of evacuating to our work’s ‘shelter’ area which amasses to little more than an open hallway, without access to my computer with accurate radar data.

A Tornado Watch still remains in effect for the entire DFW Metroplex, southeastern Oklahoma and western Arkansas until 1am. Another rain band is approaching from the west, with an approximate ETA of around 11pm to midnight tonight to Frisco/Plano/The Colony. Rain chances will continue Thursday, however nowhere near the levels observed the past two days. Hot and humid conditions should be expected the remainder of the week and weekend as the sun comes out and starts evaporating the abundance of water on the ground.

Lastly ill end with a quote from the local weather forecast office regarding the heavy rains the last two days…

DFW AND WACO HAVE BOTH SET CALENDAR-DAY PRECIPITATION RECORDS TODAY (SEPT 8). FOR BOTH SITES…THE 24-HR TOTALS (SEPT 7-8) WILL RANK AMONG THE TOP 10 ALL-TIME. PRECISE NUMBERS WILL BE AVAILABLE THURSDAY MORNING.

AT THE PRESENT TIME…THIS MONTH WILL RANK AS THE 4TH WETTEST SEPTEMBER ON RECORD FOR BOTH DALLAS/FORT WORTH AND WACO.

Flash Flooding around the entire DFW Metroplex

Sean Toner — Wed, 08 Sep 2010 14:08:07 +0000

Hey group… its been awhile but the weather conditions today merit an email… By now we are all aware of the heavy rainfall affecting the region, but may not be immediately aware of the flash flooding occurring around the region. Right now, several flash flood reports have come in from the area, including Plano, Dallas, Fort Worth and Saginaw. Major intersections in Plano near the George Bush Turnpike are submerged, low water crossings in Dallas are under several feet of water, and intersections around Fort Worth are impassible due to water. All stations in the area show at least 3 inches of rain with some showing 6 to 7 inches in the last 24 hours, which easily surpasses the criteria needed for flash flooding conditions. Below is radar estimated total rainfall. You can see Fort Worth is showing a large swath of 7 to 8 inch estimates so far. Stay safe everyone, and do not attempt to drive into submerged intersections!

New Gallery: Early Spring Snow Storm in Frisco

Sean Toner — Sun, 21 Mar 2010 20:20:23 +0000

This is post number 500 for Watching the Skies, an exciting achievement!
The pictures here were taken in Frisco, TX during the afternoon of March 21, 2010 after our spring snow storm.

[nggallery id=87]

Snowfall totals for our late March snowstorm

Sean Toner — Sun, 21 Mar 2010 19:37:40 +0000

This unseasonably late snowfall further increased the 2009-2010 snowfall totals for our area, bringing us within 1/2 an inch of the all-time snowiest winter on record! Additionally the last time this much snow fell this late in the season was March 29 1937! Preliminary snowfall totals listed graphically below.

As you can see, the heaviest snow was concentrated within Collin County including a report in Frisco of 6 inches, and 8 inches reported in Allen. DFW Airport officially documented 1.3 inches of snowfall total from this event. The statement from the NWS included below.

The snow will not remain very long, as temperatures will quickly recover to the 60s on Monday and 70s by Tuesday. The next storm system will begin to affect the region on Wednesday evening, with thunderstorms likely. A shot of cooler air will follow as this system passes, but nowhere near this level of winter weather we just received.

...Spring snow for dfw...

Dfw Airport recorded 1.2 inches of snow on March 20th. This breaks
the previous daily record for March 20th of 0.4 inches set in 1970.
An additional 0.1 of an inch officially fell on March 21st and the 

event total is 1.3 inches. 

The additional 1.3 inches brings the 2009-2010 winter total to 17.1
inches. This ranks second of all time and came 0.5 inches shy of
tying the all-time record of 17.6 inches set in 1977-1978. 

This snow event was unseasonably late in the year. The last time an
inch or more fell at dfw later than March 20th was when 2 inches
fell on March 29th in 1937.

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Dallas/Fort Worth - snowiest seasons

   1   17.6   1977-78
   2   17.1   2009-10*
   3   15.3   1963-64
   4   13.5   1923-24
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17

   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42
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Snowfall possible Saturday evening!

Sean Toner — Fri, 19 Mar 2010 17:28:45 +0000

I thought Winter was over… but it apparently has one last bite before fading away. Snowfall is possible across the northern areas of the region on Saturday evening. Accumulations will be light, if any. Areas around the Red River could receive up to 1 inch of accumulation on exposed areas. Prior to the snow however a very strong cold front will move through the area, bringing a line of thunderstorms with it. The timing on these storms right now is probably in the overnight hours tonight, into early Saturday morning. Expect very windy and cold conditions immediately after the front moves through, with the snow following several hours afterward.

The last freeze of the season is expected for the region Saturday night, so take action on Saturday to protect any sensitive vegetation since the growing season has already begun.

Below is a diagram detailing the average date of last freezes across the region… It looks like we are right around average here.

I will send more details as needed later…

Snowfall for all of north Texas on Tuesday

Sean Toner — Mon, 22 Feb 2010 07:16:45 +0000

Hey folks, looks like all of north Texas will receive some snowfall yet again on Tuesday Feb 23. Counties south of I-20 are currently under a Winter Storm Watch with forecasts estimating 4+ inches of snow, while counties in and north of the metroplex are forecast to receive 1-3 inches. Isolated areas of the southern metroplex could receive 4-5 inches, while areas south of I-20 could receive up to 8 inches! Expect additional Winter Storm Watches and Warnings to be issued Monday morning as this event approaches.

Snowfall for our region will begin around 3am, and last through until 6pm. Temperatures will sit near or at freezing, so accumulations will be light to moderate. Icing will be possible on bridges during the day, while well traveled roadways may not be too adversely affected. Temperatures overnight will reach the high 20s so icing on bridges and untraveled roadways will become likely and hinder travel for Wednesday morning. Temps for Wednesday will reach the mid 40s so accumulations will likely melt clear away.

Some additional things to mention here however… I'm sure alot of you have noticed that this season's snowfall forecasts have been somewhat inaccurate. December 24th's forecast was 1-2 inches, with 3.0 inches actually falling; February 11's forecast was less than 1 inch only 24 hours before the snow began falling, with the end result being 12.5 inches. So, take snowfall estimates with a grain of salt as they tend to be subject to huge errors, and anticipate the worst.

Secondly, DFW airport's winter season snowfall record could easily be broken with this Tuesday's snowfall event. Currently the 2009-2010 season sits at 15.7 inches of snowfall total placing us in the number 2 spot. With just an additional 2.0 inches of snow we would become the snowiest year in Dallas' history!

Finally I will close with a comment from the most recent forecast discussion provided by the National Weather Service: EL NINO WINTERS…YOU GOTTA LOVE THEM.

Daily snowfall record shattered for DFW!

Sean Toner — Fri, 12 Feb 2010 07:11:42 +0000

February 11, 2010 broke the all-time snowfall record for any calendar day and any 24-hour period with 11.2 inches of snow, as of midnight. This surpasses the previous daily record of 1.4 inches on Feb 11, 1988. This also exceeds our 24-hour record of 7.5 inches on Feb 17, 1978 and Feb 25, 1924. Lastly this breaks our greatest calendar-day snowfall total of 7.8 inches from January 15, 1964 and January 14, 1917.

Thursday’s snowfall has brought our seasonal snowfall total to 14.4 inches, the 3rd snowiest winter on record for DFW. Had there been no other snowfall events this entire season, our winter would have still made the top five snowiest, wow! Below are snowfall totals reported as of 11:30pm 2/11/10.

The impacts from this snowfall will be felt quite heavily the morning of Friday February 12th with heavy snowfall accumulations on area roads, plus icing on roadways and bridges. Afternoon temperatures for Friday have been revised downward to 38 degrees. This means snow will melt significantly but not all of it will melt before re-freezing overnight through Saturday. Expect icing conditions Saturday morning as well. Saturday high temps will reach the 50s and any remaining snow will melt off.

Additionally, I walked around and snapped some great pictures with my camera this evening. I have attached the updated gallery below.

[nggallery id=84]

Public Information Statement issued by the National Weather Service as of Midnight 2/12/10:

...Snow event one for the record books...

At midnight...dfw Airport had recorded 11.2 inches of snow today.
This breaks the previous daily record for February 11 of 1.4 inches
set in 1988. This also breaks the previous 24-hour record for
February...7.5 inches on February 17, 1978 and February 25, 1924.

This is the greatest calendar-day snowfall total on record for
Dallas/Fort Worth. The previous record was 7.8 inches on January 15,
1964 and January 14, 1917.

This brings the seasonal snowfall total to 14.4 inches...which is
the 3rd highest seasonal total on record for Dallas/Fort Worth. This
is the snowiest winter in 32 seasons (since 1977-1978).

--------------------------------------------------------------------

Dallas/Fort Worth - snowiest seasons

   1   17.6   1977-78
   2   15.3   1963-64
   3   14.4   2009-10*
   4   13.5   1923-24
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17
   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42

--------------------------------------------------------------------

Dallas/Fort Worth - most snow in February

   1   13.5   1978
   2   11.2   2010*
   3    7.5   1924

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Dallas/Fort Worth - greatest 24-hour snowfall totals

   1   12.1   January 15-16, 1964
   2   11.2   February 12, 2010*
   3    8.2   January 14-15, 1917
   4    7.5   February 17, 1978
        7.5   February 25, 1924
   6    6.0   March 13, 1924
   7    5.5   December 9, 1898
   8    5.0   November 22, 1937
        5.0   January 5, 1910
  10    4.7   November 13, 1976

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DFW Snow Update: Snowiest day Dallas’ history!

Sean Toner — Fri, 12 Feb 2010 01:20:49 +0000

The latest from the National Weather Service, snowfall today now shatters the previous record at DFW Airport. A whopping 7.9 inches 11.2 inches of snow has fallen today 2/11/10, surpassing the previous single calendar day record of 7.8 inches set on 1/15/1964 and 1/14/1917. The real kicker, snowfall is set to continue for a few more hours! This makes February 11th the snowiest calendar day, and snowiest 24 hour period in the history of DFW Airport. This winter season is now the 4th 3rd snowiest winter on record at 11.1 14.4 inches total. Details below…

...Snow event one for the record books...

At 7 PM...dfw Airport had recorded 7.9 inches of snow today. This
breaks the previous daily record for February 11 of 1.4 inches set
in 1988. This also breaks the previous 24-hour record for
February...7.5 inches on February 17, 1978 and February 25, 1924.

This is the greatest calendar-day snowfall total on record for
Dallas/Fort Worth. The previous record was 7.8 inches on January 15,
1964 and January 14, 1917.

This brings the seasonal snowfall total to 11.1 inches...which is
the 4th highest seasonal total on record for Dallas/Fort Worth. This
is the snowiest winter in 32 seasons (since 1977-1978).

--------------------------------------------------------------------

Dallas/Fort Worth - snowiest seasons

   1   17.6   1977-78
   2   15.3   1963-64
   3   13.5   1923-24
   4   11.1   2009-10*
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17
   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42

--------------------------------------------------------------------

Dallas/Fort Worth - most snow in February

   1   13.5   1978
   2    7.9   2010*
   3    7.5   1924

--------------------------------------------------------------------

Dallas/Fort Worth - greatest 24-hour snowfall totals

   1   12.1   January 15-16, 1964
   2    8.2   January 14-15, 1917
   3    7.9   February 11, 2010*
   4    7.5   February 17, 1978
        7.5   February 25, 1924
   6    6.0   March 13, 1924
   7    5.5   December 9, 1898
   8    5.0   November 22, 1937
        5.0   January 5, 1910
  10    4.7   November 13, 1976

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New Gallery: Feb 11, 2010 Record Breaking Snowfall

Sean Toner — Fri, 12 Feb 2010 01:11:26 +0000

Some images from my Flickr of this record breaking snowfall for the Dallas/Fort Worth Metroplex.

[nggallery id=84]