Jim Spencer

Warmer weather for ABC Zilker Kite Festival

February 26th, 2015 at 5:38 pm by under Weather

The good news for the ABC Zilker Kite Festival is that the weather will be much warmer, with only a slight chance for rain showers. This coming a year after the event was rained out on two successive weekends. There may not be much sun, or a lot of wind, but hopefully enough to launch the hundreds of kites expected at the park.

2-26 Kite FX


Threat of wintry precipitation returns Friday through Saturday morning

February 26th, 2015 at 3:40 pm by under Weather

A wintry mix of sleet and snow will be possible for areas in blue Friday morning and the possibility will continue for areas north of the pink line into the afternoon hours. Precipitation will remain light and little to no accumulations are expected. Areas north of the pink line will have the best chances for any accumulations and mainly on elevated structures, bridges, and overpasses.

The threat for wintry precipitation will shift to freezing rain Friday night through Saturday morning for areas highlighted in purple. Temperatures will be in the 30-32 degree range and light icing on elevated surfaces such as bridges and overpasses will be possible.
——————————–

This is the latest update from the National Weather Service:

Headline:

Another round of wintry mixed precipitation on the way from Friday morning through 10 am Saturday.

Area of Concern:

The primary area will be the Hill Country, with lesser chances along the I-35 corridor and Balcones Escarpment west of San Antonio. All of Metro Austin will be in the threat area, but Metro San Antonio should be outside of the threat area.

Threats & Impacts:

Expected Accumulations: We expect generally light amounts — up to 1/4 inch of snow in the Hill Country, and only a few hundredths of sleet or freezing rain/drizzle along the I-35 Corridor and Balcones Escarpment west of San Antonio

Impacts:  The primary impacts are expected to be patchy slippery spots, primarily on bridges, overpasses, and other elevated surfaces (e.g., picnic tables).

Timing and Overview:

Moist Gulf air will lift over cold air near the ground to produce the wintry mix of precipitation. As with the other events this winter, we expect precipitation amounts to be light, and generally be more of a travel nuisance than a threat to safety. The Friday evening rush hour may be slowed significantly, especially in the Hill Country, as the precipitation will begin there first. All of the precipitation should end by 10 am on Saturday as temperatures warm above freezing.

Confidence:

High for the temperatures being cold, Moderate for the precipitation mix and amounts.


Another chance of freezing precipitation by Friday

February 25th, 2015 at 3:50 pm by under Weather

Not again. Here is the latest update from the National Weather Service regarding another possible round of freezing precipitation in Central Texas as early Friday.


A strong cold front will move through Thursday evening causing cold air to filter into the area. This will combine with precipitation over the area Friday and Saturday. Snow and Sleet are possible on Friday, with freezing drizzle forecast for Saturday morning. Check back as the extent of precipitation and precipitation type may change.

Headline:

Another round of wintry mixed precipitation on the way from Friday morning through noon Saturday.

Area of Concern:

The primary area will be the Hill Country, with lesser chances along the I-35 corridor and Balcones Escarpment west of San Antonio. All of Metro Austin will be in the threat area, but most of Metro San Antonio should be outside of the threat area.

Threats & Impacts:

Expected Accumulations: We expect generally light amounts — up to 1/4 inch of snow in the Hill Country, and only a few hundredths of sleet or freezing rain/drizzle along the I-35 Corridor and Balcones Escarpment west of San Antonio

Impacts:  The primary impacts are expected to be patchy slippery spots, primarily on bridges, overpasses, and other elevated surfaces (e.g., picnic tables).

Timing and Overview:

Moist Gulf air will lift over cold air near the ground to produce the wintry mix of precipitation. As with the other events this winter, we expect precipitation amounts to be light, and generally be more of a travel nuisance than a large threat to safety. The evening rush hour may be slowed significantly, especially in the Hill Country, as the precipitation will begin there first. All of the precipitation should end by Noon on Saturday, and temperatures will warm above freezing.

Confidence:

High for the temperatures being cold, Moderate for the precipitation mix and amounts.


Winter Weather Advisory issued for San Saba County

February 24th, 2015 at 11:24 pm by under Weather

Winter weather is expected again tonight across much of the Big Country, Concho Valley, and Heartland. The best chance for snow will be between 2 AM and 8 PM, with rapidly improving conditions Wednesday morning. Snow amounts of 1 to 3 inches are possible in the advisory area. Some roads will become slick and hazardous, so slow down and drive with caution.

Rain/snow mix possible early Wednesday

February 24th, 2015 at 3:00 pm by under Weather

Another cold night expected across South Central Texas. Lows will range from the lower 30s across far northern areas, to near 40 across the Rio Grande Plains. An upper level low will move across north Texas resulting in showers along and east of US 281. Across the far northern Hill Country temperatures could get cold enough to have that rain mix with a bit of snow. No accumulation is expected.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
254 PM CST TUE FEB 24 2015

TXZ171>173-250400-
LLANO-BURNET-WILLIAMSON-
INCLUDING THE CITIES OF...LLANO...BURNET...GEORGETOWN
254 PM CST TUE FEB 24 2015

...LIGHT RAIN/SNOW MIX POSSIBLE OVERNIGHT INTO EARLY WEDNESDAY
MORNING...

AN UPPER LEVEL TROUGH WILL MOVE ACROSS TEXAS LATE TONIGHT INTO
WEDNESDAY MORNING. CHANCES OF PRECIPITATION INCREASE OVERNIGHT.
FORECAST ATMOSPHERIC PROFILES INDICATE A POTENTIAL FOR SNOW TO MIX
IN WITH THE RAIN ACROSS LLANO...BURNET AND WILLIAMSON COUNTIES. 
DUE TO ABOVE FREEZING TEMPERATURES AT THE SURFACE...NO SNOW
ACCUMULATIONS ARE EXPECTED. HOWEVER...MODELS SHOW A SIGNIFICANT
SNOW BAND OVER WEST CENTRAL INTO NORTHERN TEXAS. PRECIPITATION
WILL END BY LATE MORNING AS THE SYSTEM MOVES OFF TO THE EAST.

PLEASE STAY TUNED TO YOUR NATIONAL WEATHER SERVICE FOR UPDATES ON
THIS WINTER PRECIPITATION POTENTIAL.

Latest information on icing threat

February 23rd, 2015 at 4:26 pm by under Weather

It will remain cloudy and cold across South Central Texas tonight with well below average temperatures. Patchy drizzle is expected across eastern areas with patchy freezing drizzle north of the I-10 corridor. No ice accumulations are expected. Lows will range from the upper 20s in the Hill Country to the mid 30s near the Coastal Plains and along the Rio Grande Plains.

Light icing has already been reported on vehicles, exposed surfaces, and some roadways today in the Hill Country and most of Williamson County. Freezing drizzle and a few isolated pockets of freezing rain are still possible through 6pm into the I-35 corridor for Hays and Travis Counties, but any accumulations that do occur on bridges and overpasses will be very light. Patchy freezing drizzle will be possible overnight, but accumulations after 6pm will be minimal. See graphic for more details.
—————————
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
324 PM CST MON FEB 23 2015

TXZ171>173-186-188>194-206>208-232330-
LLANO-BURNET-WILLIAMSON-KERR-GILLESPIE-KENDALL-BLANCO-HAYS-TRAVIS-
BASTROP-LEE-COMAL-GUADALUPE-CALDWELL-
INCLUDING THE CITIES OF...LLANO...BURNET...GEORGETOWN...
KERRVILLE...FREDERICKSBURG...BOERNE...BLANCO...SAN MARCOS...
AUSTIN...BASTROP...GIDDINGS...NEW BRAUNFELS...SEGUIN...LOCKHART
324 PM CST MON FEB 23 2015

...FREEZING DRIZZLE EXPECTED THROUGH TUESDAY MORNING ACROSS THE
HILL COUNTRY...

LIGHT PRECIPITATION IS FORECAST ACROSS PARTS OF THE HILL COUNTRY
THROUGH TUESDAY MORNING AS TEMPERATURES REMAIN IN THE MID 20S TO
LOWER 30S. ICE ACCUMULATIONS ARE NOT EXPECTED FOR THIS
PERIOD...HOWEVER...A THIN LAYER OF ICING COULD RESULT IN MINOR
TRAVEL IMPACTS ACROSS BRIDGES AND OVERPASSES. TEMPERATURES WILL
INCREASE ABOVE THE FREEZING MARK BY 11 AM TUESDAY ACROSS MOST OF
SOUTH CENTRAL TEXAS.

Latest information on approaching winter storm system

February 22nd, 2015 at 3:44 pm by under Weather

A Winter Weather Advisory is in effect for the Hill Country, also including Hays, Travis, and Williamson Counties. The main threat early Monday morning for light icing on exposed surfaces will be over the far western Hill Country. The threat for light ice accumulations will spread to the northern areas of the I-35 corridor by Monday afternoon as temperatures drop into the lower 30s on Monday.

Cold air will surge south through the overnight and combined with light rain some freezing rain pockets should develop across the hill country. The timing for the hill country on any light freezing rain accumulation will be from 3am-3pm Monday. The freezing line will expand slightly through the day Monday with areas highlighted in Blue possibly seeing some light freezing rain from 10am to 6pm Monday. The area outlined in Purple is where the Winter weather advisory is located.
——————————————
Here is the latest message from the National Weather Service regarding the approaching winter storm system:
HEADLINEWinter Weather Advisory in effect on Monday from 3 AM-6 PM for western portions of South Central Texas including the Hill Country and Williamson/Travis Counties…Some travel impacts are possible…
Another Winter Weather Event with a whole lot of ????????  Please monitor the forecast and area temperatures closely the next 24 hrs.
…COUNTIES IN THE ADVISORY…
Williamson, Travis, Burnet, Llano, Gillespie, Blanco, Hays, Kerr, Kendall, Bandera, Real, Edwards, Val Verde
AREA OF CONCERN
 
  • Cold Arctic Air - All of South Central Texas.
  • Freezing Rain/Drizzle Monday Morning  -  Mainly along and north of a line from Juno-Kerrville-Burnet on Monday morning.
  • Freezing Rain/Drizzle Monday - western Hill Country. Small chances along the I-35 corridor (Hays/Travis/Williamson)
  • Freezing Rain Monday Night/Tuesday Morning -Low chances for northern and eastern areas.                                  .
 …IMPACTS
  • Less than .05  of ice accumulation expected. Accumulations only expected on exposed surfaces, bridges and overpasses. Worse accumulations will be in the northern Hill Country where temperatures may dip below 30 degrees.
  • Travel impacts should be minor as ground temperatures should remain quite warm initially. Exposed surfaces, some bridges and overpasses may see minor icing, and slippery walkways are anticipated. Rainfall is expected to be light so any accumulations should be a gradual process.
TIMING
  • Arctic air will remain in South Central Texas through Tuesday.
  • Chance of freezing precipitation will begin around daybreak Monday morning over the far western Hill Country with the threat spreading across the northern sections of South Central Texas by mid to late afternoon Monday.  Threat could extend into Monday Night.
CONFIDENCE… Arctic Air (Moderate to High)…Frozen Precipitation amounts and area (Low)
DISCUSSION
Cold air will slowly move down into the region overnight into Monday.  Temperatures will be much colder on Monday as an arctic airmass takes hold of South Central Texas and temperatures fall throughout the day.  The northern half of area will see early afternoon temperatures in the lower to middle 30s.  Across the northern Hill Country and areas along I-35 north of San Marcos, mid to late afternoon temperatures may drop to the freezing mark.
Some weak disturbances coming in from the west will help develop some light rain and drizzle through the day on Monday possibly lasting through Monday night into Tuesday.  This combination of arctic air and precipitation may allow for some light icing on exposed surfaces, bridges, overpasses, cars, etc. A Winter Weather Advisory has been issued for the western most areas of South Central Texas including the Hill Country and Travis/Williamson Counties.  The advisory is in effect from 3 AM-6 PM on Monday.   See the attached graphic for the counties under the advisory.
We don’t see any threat of icing in the Austin area for the Monday Morning Commute. Any threat of light icing early Monday morning will be over the far western Hill Country where temperatures are expected to be coldest during the predawn hours…near the freezing mark.  The threat of light icing on bridges and overpasses will increase across the Advisory Area  during the day on Monday as temperatures drop to near the freezing mark by late afternoon.  Since we are expecting temperatures to be somewhere in the 30-35 degree range in the advisory area, the warm ground temperatures should keep the icing to a minimum, mainly exposed surfaces and bridges.  If the temperatures drop below forecast numbers, the impact from ice would likely increase.
By Monday night, the freezing line will drop a bit farther south and east as colder air continues to filter into the area. Rain chances will be lowering however as the main area of moisture and rains moves to the east.  If there is a bit of lingering rain activity around Monday night, the colder temperatures would still allow for some light ice accumulation.  If that would occur, the advisory would likely have to be extended into Monday Night.  Residents of South Central Texas need to monitor the forecast closely over the next 24 hours as the weather conditions can change very quickly.

Public invited to free SKYWARN training Saturday

February 20th, 2015 at 10:24 pm by under Weather

 

skywarn

24th Annual
  Lou Withrow SKYWARN
  Austin / South Central Texas
  Severe Weather Spotter Training Session

   ACC Eastview Campus, Building 8000, Room 8500
   3400 Webberville Road, Austin, TX 78702
Saturday / 21 February 2015

   8:15 am to 4:15 pm /  BASIC & ADVANCED TRAINING

  Sponsored by:        
         Austin Community College (ACC)
National Weather Service / Austin – San Antonio
Midland Electronics
         L C R A
         3M Austin Amateur Radio Club
         American Red Cross – Centex Chapter
City of Austin Watershed Protection

 
    Session Chairperson:          Session Asst Chairperson:        Technical Chairperson:
    Troy Kimmel (Email)            Bob Rose                                     Mark Murray

    Session Hosts:
    Larry and Barbara Gensch
    ASSOCIATED PUBLICATIONS:
    South Central Texas SkyWarn Spotter Manual (pdf)
   

     REGISTRATION:
             No advance registration required. This session is FREE of charge (other than lunch on your own).
             Plenty of Free Parking.
             Sign in / Registration starts at 8:15am the day of the training (please do not arrive before 8:15am).
             A certificate of completion will be presented to those participants, at the end of the day, for those
completing the entire training session.

      WHO SHOULD ATTEND:
             This training is open to the general public.
             Those involved in public safety and severe weather safety / recognition, such as amateur radio operators,
             first responders (police officers, firefighters and EMS officials), emergency management officials and
             media representatives (reporters, photojournalists) are encouraged to attend this important session.

     PRELIMINARY SCHEDULE:

PROGRAM HIGHLIGHTS:
             …. Basic and Advanced Spotter Training ….
           

      8:15 – 9:00 am…. Session Registration

      9:00 – 9:15 am….  Session Welcome by Troy Kimmel and Bob Rose
                                        Facility Guidelines and Reminder – Larry and Barbara Gensch

      9:15 – 9:35 am…. National Weather Service Welcome
                                            Joe Arellano, Meteorologist in Charge, NWS / Austin-San Antonio

      9:35 – 9:40 am…. South Central Texas SkyWarn Spotter Guide Update – Troy Kimmel
                                            (found at: http://www.utexas.edu/depts/grg/kimmel/skywarnbook.pdf )

      9:40 – 10:15 am….  TBA 

      10:15 – 12:00 noon…. Basic SkyWarn Training Session
                                                   Paul Yura, Warning Coordination Meteorologist, NWS/Austin-San Antonio

     12:00 noon – 1:15 pm…. LUNCH – On Your Own

     1:15 – 2:15 pm….  KEYNOTE SPEAKER – TBA

2:15 – 3:45 pm…. Advanced SkyWarn Training Session
                                           Paul Yura, Warning Coordination Meteorologist, NWS/Austin-San Antonio

3:45 – 4:15 pm…. SkyWarn Exercise and Session Close


LCRA declares current Highland Lakes drought worst ever

February 18th, 2015 at 3:16 pm by under Weather

See the recent First Warning Weather in-depth report on the possibility of the current drought lasting decades.

AUSTIN, Texas – Preliminary 2014 data shows the drought gripping the Highland Lakes is now the most severe drought the region has experienced since construction of the lakes began in the 1930s.

As a direct result of the prolonged record-dry conditions and record-low inflows from the streams and tributaries feeding the Highland Lakes, the “firm yield,” or inventory of water LCRA can provide reliably every year, has been decreased by about 100,000 acre-feet, to 500,000 acre-feet per year. (An acre-foot of water is 325,851 gallons.) Further reductions in firm yield are possible as the drought continues.

LCRA staff provided its revised firm yield estimates in an update to the LCRA Board of Directors during a Water Operations Committee meeting on Feb. 18.

In the presentation, staff reported preliminary data shows the Highland Lakes are now in a new “critical period” marking the driest conditions on record, eclipsing the 1947-57 drought that until now was the worst on record for this region.

“We’re in a historic drought like we’ve never seen in our lifetimes,’’ said Phil Wilson, general manager of the Lower Colorado River Authority. “Based on our preliminary analysis of 2014 data, we are now in a new critical period. As a result, our reliable inventory has been reduced by 100,000 acre-feet a year, to 500,000 acre-feet per year. Even in these conditions, however, lakes Travis and Buchanan remain significantly above their all-time lows, thanks to smart water management decisions and excellent water saving efforts by our customers throughout the lower Colorado River basin.”

The most water used by firm customers in a single year was about 250,000 acre-feet in 2011, far below the estimated 500,000 acre-feet per year firm yield.

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Do recent global precipitation anomalies resemble those of El Niño?

February 17th, 2015 at 8:15 pm by under Weather
(Climate.gov)

Since October 2014, sea surface temperatures (SST) across the tropical Pacific have exceeded the thresholds of weak El Niño (1), but the atmosphere has failed to really participate. Otherwise, we’d have seen above-average convection (thunderstorm activity) in the central tropical Pacific Ocean, a weakening of the surface trade winds, and a lowering of the Southern Oscillation Index and the Equatorial Southern Oscillation Index (2)—none of which showed up consistently.

However, how much does the atmosphere matter? Can the warm SSTs alone have global climate impacts? While the answer may vary depending on location and type of impact (3), here we ask whether the most recent season (the November 2014-January 2015 average) showed global precipitation responses that resemble those expected during El Niño.

What was the global precipitation pattern during November 2014 to January 2015?

Figure 1 shows the pattern of the deviations from average (or “anomalies”) of precipitation across much of the globe for the November to January average. The brown color shows regions receiving below average rain and/or snow, and green shows above average.

Figure 1. Observed precipitation from November 2014–January 2015, compared to the long-term average (in mm). Below-average rainfall is shown in brown; above-average rainfall is green. Data from CAMS_OPI, produced at NOAA/Climate Prediction Center.

Over the United States, much of the Ohio and Mississippi valleys were somewhat drier than average, while southern Texas and part of Florida were wetter than average. In South America, most of Brazil had below average rainfall. How do these patterns, and the many other features shown in Fig. 1, compare with the historically expected patterns during El Niño?

What should it have looked like?

Figure 2 shows the expected pattern of El Niño precipitation anomalies for November-January, based on an analysis of the historical data from 1981 to the present (4). At first glance, the historical El Niño pattern does not look much like what happened this year. For example, in the United States during El Niño, above average rainfall would be expected across a wider range of the southern United States. The area of below average precipitation in the Ohio and Mississippi valleys in the recent observations is broader than seen in the historical El Niño pattern (See footnote 5 for more detail for the United States).

Figure 2. Geographic pattern of deviation from average precipitation expected for November-January during El Niño, based on a statistical analysis of data from 1981 to present. The “classic” El Niño rainfall signal in this season is above-average rainfall (green) in the east-central tropical Pacific, the southern United States and Mexico, and the Horn of Africa, with below-average rainfall (brown) around Indonesia, over the Caribbean and northern South America, and across southern Africa. Units are relative, not physical. Map based on analysis by Dr. Brad Lyon at IRI, Columbia University.

Outside of the United States, the most obvious disagreement between the typical El Niño pattern and what occurred this year is in the central and east-central tropical Pacific Ocean itself, where the observed rainfall was below average while during El Niño it would nearly always be above average. El Niño normally is associated with below average rainfall over Indonesia and northern Australia, which was generally not observed this year. The same can also be said about southern Africa. In South America, on the other hand, there is moderate (but far from perfect) agreement with the expected El Niño anomalies. So, overall, how did the observations stack up?

And now the math…

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