Thursday, September 23, 2010

Tropical this week...more "Fallish" next week!


On this first full day of the Autumnal Equinox, I thought I'd reassure everyone that more fall like temperatures are only a few days away. The persistent tropical air mass and a stubborn jet stream to our north has been keeping us in the "Florida" mode for the past several weeks. On a positive note, we have had a great September as far as rainfall goes. This is important because we will be quickly entering a La Nina winter pattern, which typically is dry. So far, my backyard in Helotes has measured almost 6 inches of rain in September. As the first real cool front nears us on Sunday, look for an increase in rainfall chances, with a few thunderstorms developing along the front. After the front passes, computer models are showing dew points in the 40's and 50's for most of next week. I would not be surprised to see some of our lows drop into the 50's!

Meanwhile, the National Hurricane Center is becoming concerned that Mathew may be about to form in the Caribbean today or tomorrow. This could be trouble for Florida early next week as the cool front pushes the storm in that direction.

Monday, September 20, 2010

September Rain totals from NOAA

So far, in my backyard, we've received 5.52 inches of rain in September. Latest 3 day storm total has been 1.14 inches.

Here is the latest rainfall update from NOAA on 9-19-10:

.. September 2010 has become one of the wetter septembers at
Austin and San Antonio...

the first 19 days of September 2010 has brought one of the wetter
septembers to Austin and San Antonio. Rainfall from a cold front
late September 2nd to the early morning hours of September 3rd
was followed by scattered showers the afternoon of the 6th
and rains associated with Hermine the 7th through the 8th.
Additional rain came from isolated showers the weekend of
September 11th and 12th to Tuesday the 14th... and more widespread
rain showers from Friday the 17th through Sunday the 19th.

Rainfall for the first 19 days of September shows that September 2010
is so far the 4th wettest September at Austin Mabry... the 15th
wettest at Austin Bergstrom... and the 8th wettest at San Antonio.
With 11 more days left in September... the final figures for
September 2010 will change.

The list below shows the wettest septembers from the past compared
to the rain that has come from September 1st to 19th of 2010.

At Austin Mabry so far in September 2010... 12.19 inches of rain
has fallen. The wettest septembers at Austin Mabry from 1856 to
2009 are listed below.

1. 20.78 September 1921
2. 12.78 September 1874
3. 12.33 September 1886
4. 10.54 September 1873
5. 9.70 September 1859

At Austin Bergstrom international Airport so far in September
2010... 4.75 inches of rain has fallen.

The wettest septembers at Austin Bergstrom from 1943 to 2009 are listed
below.

1. 9.36 September 1986
2. 8.82 September 1957
3. 8.80 September 1958
4. 6.98 September 2009
5. 6.50 September 1967

at San Antonio International Airport so far in September 2010... 8.90
inches of rain has fallen.

The wettest septembers at San Antonio from 1885 to 2009 are
listed below.

1. 15.78 September 1946
2. 13.09 September 1973
3. 11.71 September 1874
4. 11.16 September 1967
5. 11.10 September 1957
6. 9.21 September 2003
7. 8.95 September 1882
8. 8.87 September 1896

The scattered showers the past few days have brought brief wind
gusts to the area.

Scattered afternoon showers and thunderstorms moving across south
central Texas today produced brief wind gusts around 30 to 39 mph
in the afternoon.

Peak wind information from a few airports across south central Texas
from the scattered showers and thunderstorms on Sunday
September 19th are listed below.

Pleasanton... ... ... ... ... ... ... ... ... ... .23 mph
New Braunfels Municipal Airport... ... ... .35 mph
Randolph AFB... ... ... ... ... ... ... ... ... ..23 mph
San Antonio Stinson field... ... ... ... ... .26 mph
San Antonio International Airport... ... ..39 mph
Austin Bergstrom international Airport... 33 mph
Austin Camp Mabry... ... ... ... ... ... ... ... 28 mph
del Rio International Airport... ... ... ... 28 mph

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Wednesday, September 8, 2010

Rainfall totals from Hermine


It's been a very interesting past 24hrs around here, due to Tropical Storm Hermine. As most of you know by now, the storm passed directly over Bexar County around noon on Tuesday the 7th, dropping lots of rain and giving the San Antonio Airport wind gusts to 60mph. At my place in Helotes, winds stayed in the 30's. Rainfall totals have been impressive for most of our area and I have posted some latest graphics with this posting. For my backyard, we've had just over 4 inches, but that total is actually much less than most of Bexar and surrounding counties as you can see by the graphics I have posted from Weather Underground. We missed the big rains last night and are currently missing a "Rain Train" that has developed within a few miles of here, extending from near Hondo, through Fair Oaks and all of the way to north of Austin. This line of storms has moved little in the past 5 hours!

Tuesday, September 7, 2010

Hermine moving more northerly now...less rain, more wind!


This is what I was worried about....the latest update on Hermine from our local NOAA office:

Hermine made landfall late last night just south of Brownsville...and is currently tracking north across south Texas. Current position is near Alice where they are getting tropical storm force wind gusts near 50 mph. The storm is moving slightly to the right of the current forecast track.

The track of Hermine will take the storm north during the day, crossing near the San Antonio area by 1pm. The storm continues to move north at 17 mph. This has allowed the storm to keep its strength a little longer than earlier anticipated. Because of this, am introducing some possible wind impacts across the far southern areas of South Central Texas over Atascosa, Frio, and Karnes Counties. Across these counties, tropical storm force winds of 40 mph are possible, with some gusts up to 50 mph. These winds could start as early as 9am...and last several hours through early afternoon. These winds may be strong enough for some minor wind damage and power outages. Will have to watch this closely as wind impacts could move farther north into the San Antonio area. Gusty conditions will prevail elsewhere across South Central Texas during the day with winds forecast of 25 to 35 mph...some gusts as high as 50 mph in the heavier rain bands.

Because of the fast movement and track of the storm, we are scaling back our total rain forecast, especially over western areas. I have attached the latest graphic with our thinking of rainfall potential. 3-5 inches mainly east of a Kerrville to Pearsall line, 1-3 inches west of this line. We can still get some isolated totals in the 8-10 inch range...but my confidence of this is going down because of Hermine's fast movement.

East of the forecast track...the threat of isolated tornadoes will remain. Tornado watches will likely be in effect for portions of the day. The small tropical tornadoes typically occur in the strongest storms/rainbands. This threat area will be mainly east of 281 late this morning and afternoon as storms intensify. The tornado threat will lower tonight as the storm moves out of our area.

So as a recap...the threats are changing. Wind threat will increase through this morning over the southern half of South Central Texas as Hermine moves quickly north. Damage is being reported in Jim Wells County. Widespread flash flood threat is decreasing. Flash flooding will still likely occur in some locations, but overall rain amounts should be lower than originally anticipated due to Hermine's fast movement to the north.

For the latest watches, warnings, and advisories....check our website atwww.srh..noaa.gov/ewx

Paul Yura
National Weather Service Austin-San Antonio TX

Monday, September 6, 2010

Latest from NOAA-6pm


Here is the very latest from our local NOAA office about Tropical Storm Hermine:

No major changes from our earlier updates on the heavy rain event that is forecast over the area on Tuesday. Already today we are starting to see the moisture surge into the coastal plains of Texas ahead of Hermine. This will likely continue over the next 36 hours as Hermine makes landfall, and then tracks northward up into the western Hill Country by Tuesday night.

The track of Hermine has been fairly steady during the day...making landfall tonight south of Brownsville...and then moving steadily north northwest overnight. By early afternoon Tuesday, the center of the weakening system will be just east of Eagle Pass...and then be near Uvalde by 7 pm Tuesday evening.

Since Hermine has sped up...I am updating our target window of highest threats to include 10am-10pm on Tuesday for most of the area. Its during the late morning, afternoon, and evening on Tuesday that south central Texas will likely see its heaviest rains. Areas over the western and northern Hill Country will see the threat time expand several hours past midnight early Wednesday morning.

Widespread rains of 2-5 inches are possible...with blinding tropical downpours and rain rates of 1-3 inches per hour. This will likely cause flash flooding in some areas and is why we have a Flash Flood Watch out until noon on Wednesday. As bands of rain set up and move north through the area, there is the possibility of some isolated rain totals near 12 inches. Flash flooding is the #1 weather related killer. Take precautions now. There will likely be flooded roads somewhere in South Central Texas by this time tomorrow. Heed warnings and dont drive through low water crossings. As the system moves north into the Edwards Plateau after midnight early Wed morning, our heavy rain threat will lower. Only residual flooding on creeks, streams, and rivers will likely remain on Wednesday.

As we saw in Dolly...areas to the right of the tropical cyclone's track could see isolated tornadoes develop in the strongest showers/storms/rainbands. Be on the lookout for these small tornadoes as they will occur very quickly and with little warning. The pockets of damage are usually fairly small and isolated, but can bring additional tree and structure damage.

A wind advisory has been issued for most areas of South Central Texas with gusty winds of 20-30 mph expected on Tuesday. By far, the main threats with the system remain the heavy rainfall and isolated tornado threat.

Please see the latest forecast, watches, warnings, and advisories on our website at
www.srh.noaa.gov/ewx

Paul Yura
National Weather Service Austin San Antonio TX
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Here comes Hermine!


Here is the latest info from NOAA on Tropical Storm Hermine...

Overnight, Tropical Depression #10 strengthened a bit and is now officially Tropical Storm Hermine. Hermine is forecast to remain a tropical storm before she makes landfall early Tuesday over northern Mexico just south of Brownsville. I have attached the latest track of Hermine.

This means the heavy rain threat will continue for South Central Texas through at least mid day on Wednesday. A Flash Flood Watch has been issued for all of South Central Texas starting midnight tonight and lasting until Noon on Wednesday. As Hermine makes her way onshore, Gulf moisture will spread north into the region. This rainfall will start as early as today along the southern coastal plains and continue through Wednesday as the storm moves across southern areas of Texas and into the Hill Country by Wednesday afternoon.

The main threat for our area will be the heavy rainfall. The 24hr time frame from Noon Tue to Noon Wed appears to be the time for the highest likelihood of flooding...with Tuesday night still possibly being a bullseye for flooding somewhere in our area. Flood events very often happen at night during tropical events. Rain rates of 1-3 inches per hour will likely lead to flash flooding across the region with widespread rain totals of 2-5 inches expected....isolated higher totals of 5-10 inches in a few spots. I have attached a graphic from our office showing the threat area. I have also attached a graphic showing the region-wide rainfall potential. Remember that Flash Flooding is the number one weather related killer.

As Hermine gets better organized over the next 24 hours, this will spread a small tornado threat into south central Texas over the next 48 hours. Typically we will see the highest threat area to the right of the landfalling track. These tropical tornadoes come with little warning as they usually remain fairly small and can last for generally less than 10 min. They can bring small pockets of damage like we saw with Dolly in 2008.

Rain chances will decrease by Wednesday night and Thursday as the main circulation will be moving north into the southern plains out of our area. Please keep up to date on the latest forecast track of Hermine and our Flash Flood potential by going to our website at www.srh.noaa.gov/ewx

Stay safe and alert.

Paul Yura
National Weather Service Austin-San Antonio TX

Wednesday, September 1, 2010

Almost no rain in August, watch out for Gaston and a "not so hot" front on the way!


For more timely updates please see my postings on Mark Langford's Weather Page.

For the entire month of August, only 0.12 of rain fell at my place. The lack of rain and the high temps have extremely stressed my yard and pocketbook for the watering I'm doing just to keep my plants alive. La NiƱa is definitely back!

Gaston has formed this afternoon out in the Atlantic...this one bears watching since some of the models are taking him into Florida and possibly the Gulf.

I now have some new employees working for my weather page...


An early season "not so hot" front will limp through our area tomorrow night, giving us a chance for some scattered showers. So far, in my backyard, I've gotten the scattered part of the showers instead of the showers!