Friday, April 30, 2010

Rain chances are quickly going "poof"!


The chances for rain early next week have gone "poof"! Our best chance for rain will be tonight through Saturday night, as a weak cool front slowly moves through our area. Most of the severe storms and heavier rain will stay far to the NE. Storm chasers will be active in Missouri and eventually Arkansas and points eastward over the weekend. Right now, this weekend doesn't look as dangerous as last weekend.

A large area of tornado watches are out this afternoon. Everything is staying to the NE of us...at this point, I'll be surprised if we get more than a tenth of an inch of rain around San Antonio in the next 24 hrs.

Sunday, April 25, 2010

Warm and dry week ahead.


I always say that San Antonio's Fiesta marks the beginning of summer down here and looking at the latest computer models, it appears to be right on track. We should see our first 90's this week and rain chances remain slim until late next weekend when a front pushes through. As it does, look for a chance for some more severe weather, especially to our north.

On the good side, I should be swimming in my pool for the first time this season...

Saturday, April 24, 2010

Hail Reports from this morning...

04/24/2010 0148 am

2 miles N of Alamo Heights, Bexar County.

Hail m1.00 inch, reported by trained spotter.


04/24/2010 0124 am

4 miles N of Somerset, Bexar County.

Hail e1.00 inch, reported by public.


04/24/2010 0125 am

6 miles N of Somerset, Bexar County.

Hail e0.25 inch, reported by storm chaser.


04/24/2010 0135 am

4 miles ENE of Lackland afbset, Bexar County.

Hail e0.70 inch, reported by amateur radio.


04/24/2010 0136 am

3 miles WSW of San Antonio, Bexar County.

Hail e1.00 inch, reported by public.


04/24/2010 0145 am

Converse, Bexar County.

Hail e0.50 inch, reported by amateur radio.


04/24/2010 0147 am

Windcrest, Bexar County.

Hail e1.00 inch, reported by public.


04/24/2010 0148 am

Alamo Heights, Bexar County.

Hail e0.88 inch, reported by public.


04/24/2010 0154 am

3 miles NE of Leon Valley, Bexar County.

Hail e0.25 inch, reported by public.


04/24/2010 0155 am

1 miles se of Olmos Park, Bexar County.

Hail e1.50 inch, reported by broadcast media.


04/24/2010 0148 am

Alamo Heights, Bexar County.

Hail e0.88 inch, reported by public.



04/24/2010 0154 am

3 miles NE of Leon Valley, Bexar County.

Hail e0.25 inch, reported by public.


04/24/2010 0145 am

Converse, Bexar County.

Hail e0.50 inch, reported by amateur radio.


04/24/2010 0147 am

Windcrest, Bexar County.

Hail e1.00 inch, reported by public.







Friday, April 23, 2010

Still waiting for those severe storms...


Well, round one of severe storms fell apart during the evening as a cool front went stationary during the night. At 3pm., the second upper low is moving out of far West Texas and some storms are starting to form as it moves eastward. With a stationary front to our north, a very active jet stream above us, a hot and humid afternoon with lots of sun, it should be the perfect recipe for a large squall line to form later today or tonight. I'm hoping there still might be a chance for an isolated storm to form this afternoon before the upper low moves in tonight.

As of now, all of the big storms and tornado watches have been in the northern Louisiana-Arkansas area. I really thought we would see a severe outbreak of storms to our west by now...but based on the latest modeling data, they may not come in until after midnight. I'm not much of a night time storm chaser!

3pm NOAA Update

A weak front/dryline has just about stalled across the I-35 corridor from Granger Lake down through central Hays County...down to Hondo. Along and east of this boundary the atmosphere remains very unstable. Right now there is a "lid" on the atmosphere keeping thunderstorm development at bay. As we continue to warm this afternoon...there is a chance that thunderstorms could break this lid in a couple of hours...leading to possible isolated strong to severe thunderstorms. Chance of this happening is roughly 20-30%. This threat area would be mainly east of a Burnet-Boerne line. This threat will continue until about sundown, or late evening.

Then later on tonight...a strong upper level wave will move out of northern Mexico and cross the state...bringing additional lift and better chances of strong/severe thunderstorms forming somewhere near the I-35 corridor and then moving east as they intensify. This line/broken line of storms that are forecast, may form late tonight around midnight...and then exit into East Texas by sunrise on Saturday morning. Strong damaging winds and hail will be the main threats overnight. The highest severe weather threat will be areas east of I-35 and north of I-10.

We are fairly confident that if the storms form later night...they will happen mainly after midnight and over the eastern half of South Central Texas. Confidence is lower however with regards to how widespread the activity will be. In a situation like this where we have a "lid"...you could get isolated activity...or the entire lid could bust and a large squall line could develop.

For the latest information on the forecast, graphics, watches, and warnings...log onto the National Weather Service website atwww.srh.noaa.gov/ewx

Paul Yura
National Weather Service Austin-San Antonio TX

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Thursday, April 22, 2010

Severe Storm Forecast Update-3pm



It's been an interesting morning watching things develop as the cool front and upper low slowly march this direction. For San Antonio, we are in the "drizzle zone" right now, with a dew point of 64 degrees. Meanwhile, out to our west, it is sunny and storms are starting to "pop" in West Texas, the Panhandle, Kansas and Colorado. A tornado watch was just issued for most of the Texas Panhandle. Looking at regional radar, there is a very strong burst of energy emerging out of New Mexico this afternoon. As that energy moves into western Texas, look for a line of very severe storms to form. I would not be surprised to see quite a few reports of tornadoes this afternoon in that region.

For San Antonio, according to NOAA, the storms will die out before hitting us tonight, then form mainly to our east tomorrow. I'm not sure I totally agree and am leaving my schedule open for tomorrow afternoon to go storm chasing to the NW or West of San Antonio in the afternoon.

Here is what NOAA is predicting:

Some good news, in that while we still expect some severe weather across portions of South Central Texas, the main ingredients to this outbreak will focus to our W and NW tonight...and to our NE on Friday afternoon/night. Tonight we expect a lot of thunderstorm activity to form late tonight (after 6pm) across portions of west Texas. These storms will march east and possibly move into the far western hill country and southwest Texas after midnight. In addition...storms that develop over the Mexican mountains...will travel east across the Rio Grande and possibly affect areas near the river like Del Rio and Eagle Pass. At this time, this activity is not expected to make it all the way into the AUS-SAT-I-35 corridor. The main threat area tonight will remain west of a line from Burnet to Eagle Pass. Large hail and damaging winds will be the primary threat. An isolated tornado cannot be ruled out.

A dryline/weak cool front is expected to push through the western half of South Central Texas by Friday afternoon. This will allow additional storms to fire Friday afternoon/evening/night as a stronger upper level storm pushes through the state. A lot will depend on boundaries, residual cloudiness, and the dryline. Again the focus and best ingredients appear to be pooled to our east...but with that said, we will still carry a chance for severe thunderstorms mainly east of a line from Kerrville to Pleasanton.

I have attached the latest graphics that depict our threat areas both Tonight and Friday Night. Another update will be given tomorrow when hopefully we can be a little more specific on the timing and threat area for the Friday evening/overnight time period.

Please go to www.srh.noaa.gov/ewx for the lastest weather information including our graphics, forecasts, watches, and warnings.

Paul Yura
National Weather Service Austin-San Antonio TX

Wednesday, April 21, 2010

Latest from NOAA 4-21-10


Things may be shaping up for some severe storms on Friday for the San Antonio area. Although they will probably be scattered, they could reach severe levels. Here is the latest from NOAA at Noon, 4-21-10.

NOAA Special Weather Statement:

We are looking at the possibility of some severe weather toward the end of the week. A large upper low over the Western U.S. will start to move into the Southern Rockies...and then across Texas on Friday and Saturday. A couple of disturbances will be coming our way, interacting with gulf moisture to create a chance for showers/thunderstorms/severe thunderstorms. Small chances of severe weather will exist late Thursday over our far western areas as some strong storms may develop along the Mexican mountains and try to cross the Rio Grande late Thu night.

A strong wave will move into the Edwards Plateau on Friday afternoon and Friday night...helping to trigger thunderstorms along and ahead of a dryline. There are many severe weather ingredients coming together across the southern plains...including a strong jet stream, a dryline, and gulf moisture. Location and severity of the storms will be highly dependent on where the dryline sets up during the day on Friday. The best chances of severe thunderstorms will be along and east of the dryline. Models are showing that the dryline will be hanging around South Central Texas during the day on Friday...then shifting east overnight as the upper wave moves across the area. I will say however, that trying to determine the placement of the dryline several days out is very difficult. For that reason...all areas of south central Texas should be aware of this storm threat and be ready for some possible severe weather Friday afternoon and Friday night. Large hail will be the primary threat...but strong damaging winds and isolated tornadoes will also be possible.

As the event gets closer, we will provide additional updates to better focus our threat areas and timing of the event. As of right now...that threat time appears to be from 4pm Fri to 6am Saturday. The threat shifts east during the night...into Saturday morning.

Please check out our website at www.srh.noaa.gov/ewx for additional details, forecasts, and graphics.

Paul Yura
National Weather Service Austin-San Antonio TX

Sunday, April 18, 2010

Rainfall amounts and Friday Severe Weather?



Fantastic day in Helotes today! Here is a map of rainfall totals from 7am on Saturday, through this morning at 7am. Graphic is from CoCoRaHS, a great organization that allows volunteers to log in their rainfall totals on a daily basis. This information is passed on to NOAA, for calculating flood warnings and drought reports. If you enjoy logging your daily weather, I would certainly recommend becoming a member.

A slight chance of some rain on Tuesday, then all eyes will be on a very strong cold front that could spawn one of the biggest severe storm outbreaks of this season. Depending on what time of the day it comes in, San Antonio could even be impacted, along with the Battle of Flowers parade. Based on current model data, it appears that the front and weather will come in before Noon, but that could easily change this far out.

Stay tuned!

Saturday, April 17, 2010

Dry zone certainly went away!

Well...since my last blog, we've gotten almost 2.50 inches of rain, starting with a rogue cell that developed over my house around 6pm last night and dropped almost a half inch of rain in less than 15 minutes. The biggest rain for us fell this morning, between 9 and 10am. It looks like the upper low is slowly moving out and there appears to be only one more burst of energy, as another wave moves in from Mexico later this evening. Already, radar is picking up a developing line of storms in Mexico, moving west. Thanks to a weak cool front, with some dryer air, this system tonight should be the last of the rain for a couple of days.

Around mid week, another system will give us some rain chances, and then a pretty strong front will move in on Friday afternoon giving most of Texas a chance of seeing some severe storms that will most likely form along the front. Some storm chaser friends are thinking there will be an outbreak of severe weather for north Texas and Oklahoma. We shall see...
video

Friday, April 16, 2010

Not much rain so far today....


Seems like the Helotes area has been in a "dry zone" today as the upper level low drifts slowly to our NE. While we did gauge 1.32 over the past 24 hrs, most of that fell before midnight. Since then, we've only gotten less than a tenth of an inch of rain.

As I write this, around 3pm., there is a broken, rather anemic line of storms to our west. With the sun out and temperatures on the rise, it would not surprise me to see these grow a bit and give us a chance for a storm around sunset. As for the rest of the weekend, here is the latest from NOAA:


NOAA 3pm Storm Update

We expect scattered showers and thunderstorms
with light to moderate rain to continue through mid-evening,
then taper off except over the Edwards Plateau -- closer to
the upper low.

The slow moving upper low will be pulled northeast on
Saturday as another low moves through the southern
Plains. We expect another big round of showers and thunderstorms
Saturday afternoon, most likely for locations along and east
of I-35, including Metro Austin, Fiesta activities in San Antonio,
and the MS150 Bike race from La Grange to Austin. The main
threat time for these storms will be 2 pm to 8 pm. While no
severe weather is expected, these storms are likely to produce
more lightning than storms from the past few days.

Another 1 to 2 inches of rain will fall nearly everywhere from
this afternoon through 6 am Sunday. For the eastern Hill
Country and I-35 corridor, some locations will receive 3 to
4 inches of rain (see attached graphic). Flash flooding is
possible nearly anywhere, but most places will not have
problems. However, low water crossings are still an area
of high danger. Pending confirmation, we may have already
had a death due to driving on a flooded road. Please emphasize
to everyone that just because this is not a 1998 or 2002 event,
it doesn't mean it's not dangerous. We have some new flood
safety videos to view here courtesy of Pete Baldwin and
Travis County: http://www.srh.noaa.gov/ewx/?n=taddapr10.htm

River flooding is also occurring, and additional rainfall could make
the current expectations below change or become worse:

Devils River...Minor to Moderate Flooding though this evening.

Medina River at Bandera...Moderate Flooding...will fall below flood stage by this evening.

Upper Guadalupe River at Hunt...Minor Flooding, but will continue to fall
at Comfort...Above bankfull, but will continue to fall.

Frio River near Derby...Minor Flooding, will rise and and crest Sunday evening near flood stage.

Rio Grande...Above action stage and continuing to fall.

Lower Guadalupe River...Could rise this afternoon and Saturday from rainfall today. Not expected to reach flood stage.

San Antonio River...currently below flood stage and falling. Additional rainfall could cause rises into Saturday.

Only scattered showers and thunderstorms are expected during the
day on Sunday as we begin to dry out. Email Paul with rain/
flood reports and pictures, especially ones we can use for future flood
safety presentations. If you have urgent information, call our forecast
staff (numbers not given here since these emails are forwarded).

-Jon

Thursday, April 15, 2010

Heavy Rain here soon...


Here's the latest from NOAA at 1pm:

Sorry for the late update. A persistent band of showers
and thunderstorms will continue to move/develop northeast
this afternoon. We expect this band of rain to affect Metro
San Antonio, the eastern Hill Country, and the I-35 Corridor
as far north as Hays County (including New Braunfels and
San Marcos).

Rainfall amounts will average 1 to 3 inches with the band of
rain this afternoon, and a few spots could receive up to 4
inches of rain. This will produce minor flooding, including
low water crossings, frontage roads, and other low-lying areas.
The main impact will be during rush hour and for the school
buses. Please remind those in your organization that while
this is not a major flood event, a high level of caution should
be taken while driving. The number one rule is always:
Turn Around, Don't Drown. However, reducing speed and
leaving space between you and other vehicles will keep
accidents to a minimum.

-Jon

Monday, April 12, 2010

Rain delay in progress...lots on Thursday and Friday!


As most of you have noticed by now, we are currently in a "Rain Delay" in San Antonio, with all of the moisture staying west, south and NW of us. Although we may still manage some more drizzle and a lucky "popper" in the next couple of days, it looks like the bulk of the rain will hit on Thursday and Friday, as a new system moves closer to us than the last one. Rainfall estimates are impressive if they pan out...we could see 3-5 inches from this upper low!

Saturday, April 10, 2010

Rain is coming!


A quick update this Saturday afternoon...looks like we will have a chance of rain for most of this upcoming week and temperatures will trend toward below average and rainfall above average for the next two weeks. I'm fine with that combo! Latest 5 day precipitation estimate has us in the 1-2 inch rain zone. I'm fine with that, too!

Wednesday, April 7, 2010

If you didn't get much rain, don't worry!


If your backyard is like mine, it only saw about .06 of heavy drizzle this morning as the cold front moved through. A few "poppers" developed to the NW of us, but they fell apart fairly quickly. Most of the heavier rains, once again, fell to our north and east. If you're getting depressed that your nice green lawn needs some rain, fear not! The next two weeks will see below normal temperatures and above normal rainfall for most of Texas, including our area. A series of lows will start moving into South Texas starting early next week.

Meanwhile, enjoy several days of cool, dry weather, with morning lows in the mid 40's!

Sunday, April 4, 2010

Very Tropical, a few storms, then chilly!

Should be quite a "weather contrast" around South Texas as warm, tropical air starts off the first half of the week and cool Canadian air replaces it for the second half. High dew points of 63 degrees kept our low for today at 68 degrees...more like late May weather!

This pattern of warm, muggy, weather will continue through Wednesday, when a very strong front (lcfs rating of 358) moves down from Canada, dropping our temperatures below average (could see some low 40's) and pushing the tropical air back into the Gulf for a few days. As this front moves through, look for a line of storms to form which will hopefully give us some better rains than the last front...I only measured .02. Looking at the latest modeling data, most of the rain will stay to our north and NE, a pattern that is beginning to concern me. On a positive note, models continue to show a 3 day rain event from the 11th-13th for most of Texas, including our area. If this pans out, we could see 1-2 inches of rain from this event.

For all of you allergy suffers, including myself, this should be the last week of really high oak pollen. My oak trees are starting to drop their "stringers", which comes after pollination. Hopefully our morning drizzle and winds from the south for the next couple of days will give us all some relief. Unfortunately, when the front blows through on Wednesday, our winds will turn back into the north, bringing down more pollen from oak trees in the Hill Country, that are about two weeks behind us in pollination.

Thursday, April 1, 2010

NOAA update on severe storm threat 4-1-10


Based on the latest model data, I agree with this latest NOAA update from this afternoon:

The risk for severe storms has decreased for Friday,
April 2, as the low pressure system will track further to
the north across north Texas and Oklahoma. However,
isolated severe storms are still possible across the northeast
portions of our area tomorrow afternoon through early evening.

The main threat area will be along and north of Texas 71,
from La Grange to Austin to Llano. The primary threat time
will be from noon to 6 pm. The main severe threat is
damaging winds, although large hail is possible. Tornadoes
and flash flooding are unlikely.

The primary impact will be rain and wind greatly slowing
afternoon rush hour in Metro Austin, and for activities
where strong winds would be a problem (examples:
outdoor tents, temporary signs/banners).

The gusty winds and low humidity behind the cold front will
make conditions near critical for the spread of wildfires. Those
planning burning in the Edwards Plateau and Rio Grande Plains
should take that into account.

The latest information is always available at:
http://www.srh.noaa.gov/ewx

And a graphic depicting our expectations for tomorrow is below.