Daily Archives
May 11, 2017

Troy’s Special Briefings….

by troyk | on May 11, 2017 | Comments Off

Austin / Travis County and South Central Texas Weather Update #2
Prepared by UT University/Incident Meteorologist Troy Kimmel
205pm CT – Sunday / 28 May 2017

.. Authority NWS/Storm Prediction Center ..

Mesoscale Discussion 0901
   NWS Storm Prediction Center Norman OK
   0134 PM CDT Sun May 28 2017

   Areas affected...Central Texas

   Concerning...Severe potential...Watch likely 

   Valid 281834Z - 281930Z

   Probability of Watch Issuance...80 percent

   SUMMARY...A severe weather watch seems probable at some point late
   this afternoon and evening, perhaps as early as 20-21Z.

   DISCUSSION...Objective analysis indicates that insolation within a
   boundary layer characterized by high moisture content (lower/mid 70s
   F surface dew points) is contributing to strong/extreme CAPE on the
   order of 4000+ J/kg across much of the region, including the
   Interstate 35 corridor between San Antonio and Waco.  Mid-level
   inhibition beneath warm elevated mixed layer air does still appear
   considerable, particularly given weak, or at least unclear,
   mid/upper forcing for ascent.  An area of enhanced ascent
   contributing to deepening mid-level based convection near the
   Interstate 20 corridor, west of the Dallas/Fort Worth metroplex, may
   remain displaced to the north of an area of sustained enhanced
   low-level convergence near the Waco area.  This is near the
   intersection of a surface front that extends southwestward into the
   Rio Grande Valley, to the west of Del Rio, and the western flank of
   composite outflow from extensive overnight convection, now advancing
   into the north central Gulf Coast.

   However, the latest Rapid Refresh suggests that additional surface
   heating, coupled with subtle mid-level height falls on the southern
   fringe of the westerlies, may be sufficient to support the
   initiation of thunderstorms as early as 20-21Z.  Once this does
   occur, intensification likely will be very rapid, and deep layer
   shear appears sufficient for the evolution of supercell structures
   with large hail  and perhaps an isolated tornado, in addition to
   strong downbursts accompanied by potentially damaging surface gusts.

   ..Kerr/Hart.. 05/28/2017

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...HGX...FWD...EWX...SJT...

   LAT...LON   30359938 31149852 31689787 31949702 31599588 30929570
               30419690 29639779 29409830 29329912 30359938


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by troyk | on May 11, 2017 | Comments Off

Updated 915am CT – Thursday / 11 May 2017

.. Scattered Rain Showers and Thunderstorms as Front Moves Through Tonight ..
.. Drier and Less Humid with Plenty of Sun Tomorrow Through the Weekend ..
.. An Unsettled Weather Pattern Developing with Rain Chances Next Week …

On this Thursday… a stationary front extends southwestward from northeastern and western Missouri into southeastern Kansas and then into a surface low over western Oklahoma. From the surface low, a cold front extends southward into far southwest Texas west of Del Rio. As a result of this surface weather pattern, our surface winds across south central Texas are light and variable.

In the upper levels of the atmosphere, a northeastward moving upper air low pressure disturbance is over the Texas/Oklahoma panhandles. Another disturbance is located off the Pacific Northwest coast over the eastern Pacific Ocean. As a result of this upper air weather pattern, the 30,000 foot winds over south central Texas are southwesterly 80 to 90 mph.

Moist and increasingly unstable air continues to stream northward over the area in advance of the upper air low pressure disturbance and the surface cold front. The upper air low pressure area will move east northeastward into the central and southern plains today into tonight with the attendant surface cold front moving from west to east through the area between midnight and 5am tonight/tomorrow morning. With the associated atmospheric lift, we’ll see scattered rain showers and thunderstorms over the area. Based on guidance from the NWS/Storm Prediction Center, I am thinking that one or two of the thunderstorms over the area could becoming severe with an associated hail and straightline thunderstorm wind risk. Current guidance from the NWS/Weather Prediction Center and the atmospheric computer models suggest that any thunderstorms that do develop with move eastward pretty quickly with rainfall of 1/4 to 1/2 inch possible locally before daybreak tomorrow. Once the surface winds shift northwesterly with cold frontal passage, rain chances will quickly decrease with skies clearing before daybreak tomorrow.

A drier and more stable weather pattern will prevail tomorrow and through the weekend with abundant sunshine. Nighttime low temperatures will be a bit cooler due to the dryness of the air.

As surface high pressure, in the wake of the front, moves east of the area by early Sunday, southerly surface winds will pick up over the area. Low level moisture will increase over the area with late night and early morning low clouds returning as early as Monday and Tuesday mornings.

By the middle into latter parts of next week, an approaching upper air low pressure and associated cold front will move slowly eastward through the western and southwestern parts of next week. I’ll introduce rain chances beginning Wednesday with rain and thunderstorm chances, it appears, increasing even more by Thursday into Friday.

Have a good Thursday….
Meteorologist Troy Kimmel

Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel

Updated 845am CT.. Monday / 08 May 2017

TODAY…. Mostly cloudy. Scattered rain showers and thunderstorms, mainly in the afternoon, with an associated lightning risk. A 40% chance of rain; rainfall, where it occurs, at any given location, will average 1/4 inch. High 86. Southerly wind 5 to 12 mph.

TONIGHT…. Mostly cloudy. Scattered rain showers and thunderstorms with an associated lightning risk as a cold front passes after midnight. A 40% chance of rain; rainfall, where it occurs, at any given location, will average 1/4 inch. Low 67. Southerly wind 5 to 10 mph becoming more southwesterly and westerly after midnight.

FRIDAY…. Decreasing clouds through sunrise becoming sunny and less humid. High 86. North northwesterly wind 5 to 12 mph.

FRIDAY NIGHT…. A clear sky and a little cooler. Low 59. Northerly wind 5 to 10 mph.

SATURDAY…. Sunshine. High 87. Northeasterly wind 5 to 10 mph.

SATURDAY NIGHT…. A clear sky. Low 62. Light easterly wind becoming light and variable after midnight.

SUNDAY…. Sunshine. High 89. Light winds becoming southerly 4 to 8 mph by midday.

SUNDAY NIGHT…. Mostly clear. Low 66. Southerly wind 4 to 8 mph.

MONDAY…. Some brief morning low clouds, otherwise mostly sunny. High 90. Southerly wind 5 to 12 mph.

MONDAY NIGHT…. Becoming partly cloudy early then mostly cloudy after midnight. Low 68. South southeasterly wind 5 to 10 mph.

TUESDAY…. Morning low clouds, otherwise partly cloudy. High 89. Southerly wind increasing to 8 to 15 mph.

TUESDAY NIGHT…. Partly cloudy early then mostly cloudy after 10pm. Low 71. South southeasterly wind 5 to 10 mph.

WEDNESDAY…. Morning low clouds, otherwise partly cloudy. Scattered rain showers and thunderstorms with an associated lightning risk mainly in the afternoon. A 30% chance of rain; where rainfall occurs, at any given location, it will average 1/4 inch or less. High 88. Southerly wind increasing to 8 to 15 mph.

NATIONAL WEATHER SERVICE / 8 TO 14 DAY OUTLOOK
Valid Thursday / 18 May 2017 through Wednesday / 24 May 2017…
Temperature… Above Average
Precipitation… Above Average

AUSTIN SUNSET/SUNRISE TIMES…..
Sunrise this morning (11 May)……………………………………………. 6:39 am
Sunset this evening (11 May)……………………………………………… 8:15 pm
Sunrise tomorrow (12 May)………………………………………………… 6:39 am
Sunset tomorrow (12 May)…………………………………………………. 8:16 pm