Watching the Skies

One of the snowiest winters in D/FW history has finally ended, with official totals reaching 17.1 inches. Some areas even received 25 inches of snowfall this year!

A table of the top 10 snowiest winters, provided by the National Weather Service. This season ranked number 2, just half an inch behind breaking the record.

   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

The cause is undoubtedly related to El Nino, which has an indirect effect on allowing more Gulf moisture to make its way into the southern plains. This also causes the southern branch of the jet stream to bring pacific storm systems over the southern plains with greater frequency.

The National Weather Service wrote up a great summary of the numerous snowfall events this season, and can be found here

• http://www.srh.noaa.gov/fwd/?n=wintersnow09-10

DFW Airport is just 7 days short of breaking yet another record during our cold season, this time for most consecutive days below 80 degrees F.

Looks like we may end this record just a few days shy, as forecasts for Wednesday and Thursday bring our high temps above the 80 degree mark.

10 years ago today a pair of tornadoes struck heavily populated areas in Fort Worth and Arlington, killing two and injuring 80 others. The first tornado developed quickly and moved through downtown Fort Worth, causing severe damage to numerous high rises along with other structures and vehicles. A significant hailstorm also affected areas north of Fort Worth like Lake Worth and Saginaw, causing significant damage to roofs and vehicles.

(KFWS 00:25 Zulu Base reflectivity/Velocity)

The above screenshot demonstrates the storm as it was passing over downtown Fort Worth. The storm briefly produced F3 damage to the Cash America building, and F2 damage along a substantial part of its track.

(KFWS 01:05 Zulu Base Reflectivity/Velocity)

This image shows the second tornado with the strongest radar velocities near Arlington along I-20. This tornado tracked just south of I-20 for a few minutes before turning left and dissipating.

Below is a summary developed by the NWS about the tornadoes and the impact they had on the region.

NWS March 28 Fort Worth Tornado Summary

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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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.

[Show as slideshow]

[View with PicLens]

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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).

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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

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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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I have been meaning to get this sent out for 5 days now and just never get a chance! October broke the record for fewest amount of sunshine ever recorded at DFW Airport for the month. Additionally October finished out as the 7th rainiest on record, with well below average temperatures.

For October, DFW Airport recorded only 8798 minutes of sunshine, officially marking this October as the gloomiest on record. The previous record holder was 9302 minutes set in 1984. This works out to only 40% sunshine during daylight hours, or 60% cloud cover average for the month. Source: http://www.srh.noaa.gov/news/display_cmsstory.php?wfo=fwd&storyid=35837&source=0

The month also finished out in 7th place for precipitation with 8.05 inches at DFW. The record was 14.18 inches set in 1981 so there was no chance at breaking this. Out of 31 possible days, 18 days recorded measurable precipitation, 20 days reported some form of precipitation, 8 days with thunderstorms, 19 days with fog. We were nearly double the normal October precipitation, receiving 3.94 inches more than average. Source: http://www.weather.gov/climate/getclimate.php?wfo=fwd

Lastly the month of October was significantly cooler than average as well, I believe we ranked within the top 10 coolest Octobers on record too, though I cannot find the exact numbers on this right now. Average temp was 62.7, 4.5 degrees lower than average. The month was very mild, with no temperatures higher than 90, or lower than 32. Additionally overnight lows were never higher than 80 degrees. I’d say this was a very comfortable month for temperatures. Source: http://www.weather.gov/climate/getclimate.php?wfo=fwd

So far in November we are off to a very comfortable start, clear skies and very mild temperatures that are favorable for leaving the windows open all day and night. The conditions will continue until possibly Sunday evening through Tuesday when a weak cold front will be in the vicinity and bump rain chances to around 20%. I will keep an eye on this, but so far this does not look to be much more than a rain event.

Now that the heaviest rains are beginning to exist the Metroplex as they move east, I will send a brief update on tonight’s severe weather impacts. Only a few reports of high winds around the area, none of them reporting any damage so far. Several large hail reports in Parker, Tarrant, Denton and Cooke counties. One report of lightning striking a home in Trenton, 30 miles NE of Frisco, though damage is unknown at this time. Flooding impacts however are notable… several high water rescues have been reported in Fort Worth due to flooding rains stranding motorists or entering houses. Extreme north Collin county shows an estimated 6.24 inches of rainfall in the last 5 hours! The city of Celina, just 12 miles north of Frisco is embedded in a swath of the heaviest rains, reporting flood waters entering houses as well. There are also some road closures due to high waters south, and west of McKinney.

Attached is rainfall estimates since 6:22pm Sunday 10/25. You can see the area 2.5 miles north of Weston, or extreme north Collin and south Grayson counties showing up to 6.24 inches of rain. This is a result of several thunderstorms training across this area. Frisco by comparison is estimated around 1.17 inches, and only 19 miles south of the heaviest rainfall.

October 25, 1921 marks an anniversary of the last major hurricane to directly impact Pinellas County, FL. This storm inundated the barrier islands with storm surge creating several passes including Johns Pass between Treasure Island and Madeira beach. Below is an excerpt from Bay News 9  regarding this storm:

Link directly to Article
By Bay News 9 Chief Meteorologist Mike Clay

On October 25, 1921, Pinellas County was hit with the last hurricane to score a direct hit.

Since then, there have been other very close calls and storms that have done damage such as Hurricane Easy in 1950 and a strong hurricane in 1944 that hit Manatee County and came up through Tampa Bay.

But the 1921 Hurricane is a textbook case of the worst case scenario for Tampa Bay. The storm was a typical October threat for us, forming late in the season in the warm waters of the Western Caribbean.

It moved slowly northward, getting stronger and missed the land mass of Cuba and the Yucatan of Mexico passing through the warm waters of the Yucatan Channel. From there, stronger upper level winds that were likely blowing by late October turned the storm northeast as it became a category 3.

The hurricane was likely weakening as it hit with the center coming ashore at Tarpon Springs. The National Hurricane Center shows it a category 3 at landfall with winds of 120 mph, pressure of 951 mb and a storm surge in Tampa Bay of 10.5 feet.

The hurricane left 10 people dead and $10 million dollars in damage. Remember, not many people lived here in 1921. The population was only slightly over 100,000. A storm like this today would cause many billions of dollars worth of damage here along with a severe threat to life.

We can learn lessons from the 1921 Hurricane which caused water to go over the barrier islands and cut several passes in the sand bars which still exist today.

Major hurricanes can hit the West-Coast of Florida, and are most likely in October. Even though the peak of the season was back in mid-September, we have to remain cautious through the end of the season in November.

Since moving to Frisco Texas a year ago I have seen the terminology ‘In Texas it takes a flood to end a drought’ used quite a few times, now I understand why that phrase is quite accurate. So far for the month of October DFW Airport has recorded 7.09 inches of rainfall, placing us 4.12 inches above normal. Currently this October is ranked the 8th rainiest and we still have 8 calendar days left to go. The number 1 rainiest October beats all others by a very large margin at 14.18 inches in 1981 so we are likely not to break this record. However we are in striking distance of the number 2 spot which is 9.44 inches set in 1919. With at least two to three more rain days in the forecast this month we very well make the number two spot. On a side note, average temperatures this month are below normal with the October 2009 average being 65.0 and the October normal temp of 68.4. I will try to find out cloud cover percentages of this month vs normal and vs records later on… its a bit harder to find that info.

Precipitation totals for the year are also well above normal… At this time precipitation is at 36.32 inches since Jan 1, or 7.87 inches above normal. Normal annual rainfall is 37.05 inches so if we received no additional rainfall the rest of the year, we would be only 0.73 inches below normal.

The rainfall from Wednesday made up a significant portion of this month’s totals with the National Weather Service office in Fort Worth receiving the most rain at 5.81 inches. Most locations received 3 to 4 inches of rainfall during Wednesday. Some river and stream flooding is still occurring at this time including the Trinity River in Dallas, and the Denton creek near Justin. The Trinity River in Dallas is currently sitting at 36.4 feet, or 6.4 feet above flood stage.

Regarding the drought conditions in central and southern Texas… the recent rainfalls have made significant improvements to lessening the drought impacts to our south, and virtually eliminated drought conditions in all of north Texas. A small area of coastal south Texas around Corpus Christi is still in the ‘Exceptional’ drought classification, the highest possible. This area however is very tiny, in comparison to just 3 months ago when over 20% of Texas was in an Exceptional drought status. With current climate forecasts showing the weak El Nino conditions persisting throughout winter and thus above average precipitation for our region, I would expect nearly all drought in Texas to be wiped out in the next few months.

With any drought or unusual dryness you have to consider large fire impacts as well… With the abundant rainfall in the late growing season for Texas, vegetation will sprout new growth before going dormant after the first hard freeze. The hard freeze tends to dry out plant life and create excellent fuel for large wildfires during the winter and early spring. However the above average rainfall forecast for this Winter should dampen any wide spread fire impacts. Due to this, the winter looks to present a relatively low hazard for wildfires.

This information is considered ‘preliminary’ from the National Weather Service, and obtained directly from the website for NWS Fort Worth at http://www.srh.noaa.gov/fwd/

This won’t be an extensive review on climate change, simply an observation of current trends and its known impacts based on the past. So far this year El Nino conditions have popped up with average sea surface temperatures in the pacific tropical zone at least 1.0 degrees C above average. El Nino has been known to affect weather patterns globally including less tropical cyclone activity in the Atlantic basin during El Nino periods.

Looking at the Climate Prediction Center’s 6-10 day and 8-14 day forecasts, north Texas can expect more above average temperatures and below average precipitation. Keep in mind these forecast begin 6 days out, which will be after the rain event we will encounter the next several days. Beyond that, El Nino conditions tend to create warmer than average, as well as stormier than usual conditions for north Texas in the Winter.

Below is a small list of reports that NOAA, the National Weather Service, and AccuWeather have put together regarding recent observations where weather conditions have departed from normal.

El Niño Arrives; Expected to Persist through Winter 2009-10

El Niño’s impacts depend on a variety of factors, such as intensity and extent of ocean warming, and the time of year. Contrary to popular belief, not all effects are negative. On the positive side, El Niño can help to suppress Atlantic hurricane activity. In the United States, it typically brings beneficial winter precipitation to the arid Southwest, less wintry weather across the North, and a reduced risk of Florida wildfires.

El Niño’s negative impacts have included damaging winter storms in California and increased storminess across the southern United States. Some past El Niños also have produced severe flooding and mudslides in Central and South America, and drought in Indonesia.

An El Niño event may significantly diminish ocean productivity off the west coast by limiting weather patterns that cause upwelling, or nutrient circulation in the ocean.  These nutrients are the foundation of a vibrant marine food web and could negatively impact food sources for several types of birds, fish and marine mammals.

NOAA: Global Ocean Surface Temperature Warmest on Record for June

The world’s ocean surface temperature was the warmest on record for June, breaking the previous high mark set in 2005, according to a preliminary analysis by NOAA’s National Climatic Data Center in Asheville, N.C. Additionally, the combined average global land and ocean surface temperature for June was second-warmest on record. The global records began in 1880.

Climatology of Hurricane Seasons with a Late Start – By NWS WFO Ruskin

As expected, there is no major correlation to a late start to the season and characteristics of the season. Several seasons saw 10 or more TCs form with 5 or more landfalls, while other years saw 4 or 5 storms form with just a couple landfalls.

3,000 Low Temp Records Set This July! – By AccuWeather.com

1,044 daily record low temperatures have been broken this month nationwide according to NCDC — count record “low highs” and the number increases to 2,925, surely to pass 3,000 before the end of the month.