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Special Briefings….

by troyk | on May 30, 2017 | Comments Off

This is where, in periods of severe and inclement weather, I place special updates.

At this time, there is not a severe weather threat for south central Texas.

by troyk | on May 30, 2017 | Comments Off

I’m on vacation through Friday / 23 June 2017…

In my absence, click here for the latest Austin area forecast from the meteorologists at the NWS/Austin-San Antonio..

by troyk | on May 28, 2017 | Comments Off

Austin / Travis County and South Central Texas Weather Update #3
Prepared by UT University/Incident Meteorologist Troy Kimmel
310pm CT – Sunday / 28 May 2017

.. Authority NWS/Storm Prediction Center ..

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 293
NWS Storm Prediction Center Norman OK
310 PM CDT Sun May 28 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Central and Southeast Texas

* Effective this Sunday afternoon and evening from 310 PM until
  1000 PM CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms are expected to rapidly develop over the
watch area this afternoon, spreading slowly eastward this evening. 
Damaging winds and hail will be possible in the strongest cells.

The severe thunderstorm watch area is approximately along and 60
statute miles either side of a line from 35 miles south southeast of
Del Rio TX to 65 miles north of Huntsville TX. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 292...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
25025.

...Hart

WATCH COUNTY NOTIFICATION FOR WATCH 293
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
310 PM CDT SUN MAY 28 2017

TXC013-019-021-029-031-053-055-091-123-127-137-149-163-171-177-
187-209-255-259-265-271-285-287-299-323-325-385-453-463-465-491-
493-507-290300-
/O.NEW.KEWX.SV.A.0293.170528T2010Z-170529T0300Z/

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
293 IN EFFECT UNTIL 10 PM CDT THIS EVENING FOR THE FOLLOWING
AREAS

IN TEXAS THIS WATCH INCLUDES 33 COUNTIES

IN SOUTH CENTRAL TEXAS

ATASCOSA              BANDERA               BASTROP              
BEXAR                 BLANCO                BURNET               
CALDWELL              COMAL                 DEWITT               
DIMMIT                EDWARDS               FAYETTE              
FRIO                  GILLESPIE             GONZALES             
GUADALUPE             HAYS                  KARNES               
KENDALL               KERR                  KINNEY               
LAVACA                LEE                   LLANO                
MAVERICK              MEDINA                REAL                 
TRAVIS                UVALDE                VAL VERDE            
WILLIAMSON            WILSON                ZAVALA               

THIS INCLUDES THE CITIES OF AUSTIN, BANDERA, BASTROP, BLANCO, 
BOERNE, BRACKETVILLE, BURNET, CARRIZO SPRINGS, CRYSTAL CITY, 
CUERO, DEL RIO, EAGLE PASS, FLORESVILLE, FREDERICKSBURG, 
GEORGETOWN, GIDDINGS, GONZALES, HALLETSVILLE, HONDO, KARNES CITY,
KERRVILLE, LA GRANGE, LEAKEY, LLANO, LOCKHART, NEW BRAUNFELS, 
PEARSALL, PLEASANTON, ROCKSPRINGS, SAN ANTONIO, SAN MARCOS, 
SEGUIN, AND UVALDE.

$$

—–

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

by troyk | on May 28, 2017 | Comments Off

Austin / Travis County and South Central Texas Weather Statement #1
Prepared by UT University/Incident Meteorologist Troy Kimmel
1245pm CT – Sunday / 28 May 2017

.. A Weak Cold Front Progressing Southward Across Texas ..
.. A Few Strong Thunderstorms Likely this Afternoon into Tonight ..
.. Rain and Thunderstorm Chances, Along with Lightning Risk, Continues into the New Week ..

http://www.spc.noaa.gov/public/fema/images/fema06_swody1.png

Hazards Expected and Time Periods (My Confidence) …

…. Larger hail threat – between 2pm and 10pm today and tonight (medium confidence)
…. Strong straight line thunderstorm wind threat –
between 2pm and 10pm today (low to medium confidence)
…. Tornado threat – between 2pm and 10pm today (low confidence)
…. Lightning threat – after 2pm today and continuing tonight into Memorial Day (very high confidence)
…. Flood threat – after 5pm through the nighttime hours tonight – mainly urban/small stream (low to medium confidence)

Current NWS Watches / Advisories / Warnings ….
There are no current NWS watches, advisories and/or warnings in effect for our IH35 corridor counties..
Given the “slight” risk outlook area currently over our area, if conditions materialize as
expected, I would anticipate a watch from the NWS/Storm Prediction Center being eventually
issued for parts of our south central Texas area sometime in the 2pm to 10pm time period today.

Weather Discussion ….
At midday on this Sunday.. a cold front is pressing southeastward and is located along a line
from west of Texarkana to just southeast of the DFW metroplex to near Lampasas to Llano
and then to south of Junction.
Ahead of the front, plenty of gulf moisture is combining with strong atmospheric instability
to set the stage for scattered rain showers and thunderstorms as the frontal lift increases with
the surface front and an associated upper level low pressure disturbance moving through the area.
The cold front should pass the local area by late this afternoon into early evening tonight with the
threat of stronger thunderstorms decreasing thereafter.
Clouds and rain shower and thunderstorm activity will continue in the post frontal environment
tonight through tomorrow (Memorial Day) as the front weakens and starts to shift back northward
as a warm front. Bottom line, lightning will continue to be a daily hazard for much of the coming week
as a typical late spring weather pattern prevails as weak upper level disturbances move west-to-east
overhead.

Aviation Weather Information for the
Austin Bergstrom International Airport (KAUS) Aerodrome and Associated Hubs ….
Given the weak cold frontal boundary expected in our area later this afternoon into tonight, scattered
rain showers and thunderstorms, with an associated lightning risk, are expected over or
in the vicinity of the KAUS aerodrome this afternoon into tonight with stronger
thunderstorms possible.
The front is expected to pass southeastward to the Texas coastal plains by late tonight into
tomorrow; even so, post frontal rain showers and thunderstorms are expected to continue
locally, with an associated lightning risk, through tomorrow (Memorial Day) through much
of the upcoming week.

Likelihood of Hub Diversions..
DAL/DFW Aerodromes and ZFW Airspace..
Scattered rain showers and thunderstorms (50% rain) today decreasing to widely scattered
(20% rain) tonight. Some diversions and ZFW reroutes are possible mainly this afternoon into
the mid evening hours tonight.

HOU/IAH Aerodromes and ZHU Airspace..
Scattered rain showers and thunderstorms (30% rain) today increasing to scattered to
numerous (60%-80% rain) late tonight into the early morning hours tomorrow. Although
there will be lull in air traffic by the time the rain shower and thunderstorm chances peak
after midnight tonight, it is likely we’ll see some diversions and ZHU reroutes especially in
the morning hours tomorrow.


Current KAUS Terminal Aerodrome Forecast (TAF) – Issued 281735z ..

FTUS44 KEWX 281735
TAFAUS
TAF
KAUS 281735Z 2818/2924 18007KT P6SM BKN035 BKN250
     FM282000 13008KT P6SM VCTS BKN035CB BKN100
     FM282300 03010KT 4SM -TSRA BR OVC025CB
      TEMPO 2900/2902 VRB15G25KT 2SM TSRA OVC015CB
     FM290400 02010KT 5SM -SHRA BR OVC010
     FM291000 35008KT P6SM OVC008
     FM291700 07007KT P6SM BKN015 BKN120=

Current FAA National Airspace Status

CALL TO ACTION:

Please remain “weather aware” and listen for the latest weather statements,
advisories, watches and warnings from the National Weather Service (see links
below).

Make sure that your NOAA All Hazards Weather Radio is operational and are
set to alarm in case of severe and inclement weather watches and/or warnings.

FOLLOWUP STATEMENTS:

I will continue to keep you informed regarding this severe/inclement weather
event. Any questions or if you have a storm report that I can forward on your behalf
to the National Weather Service, please let me know at tkimmel@troykimmelweather.com

GENERAL WEATHER INFORMATION LINKS:

NWS/Austin-San Antonio Current Statements/Advisory/Watches/Warnings
NWS/Austin-San Antonio Web Page
NWS/Storm Prediction Center (Outlooks)
NWS/Storm Prediction Center (Mesoscale Discussions – Severe Weather & Snow)
NWS/Storm Prediction Center (Severe Thunderstorm/Tornado Watches)
NWS/Weather Prediction Center (Mesoscale Discussions – Heavy Rain & Flooding)
NWS/National Hurricane Center

tk

by troyk | on May 19, 2017 | Comments Off

Updated 915am CT – Friday / 19 May 2017

.. An Unsettled Weather Pattern Continues ..
.. Best Rain Chances Saturday through Saturday Night ..
.. Another Storm System with Rain Chances Monday into Tuesday ..

On this Friday… a surface low pressure area is over southern Kansas with a cold front extending southwestward into western Oklahoma through the southern Texas panhandle and the northern south plains of west Texas then into northeastern New Mexico. A dry line.. separating dry air to the west from moist and tropical air to the east.. extends from its intersection with the cold front over the southeastern Texas panhandle south southwestward into far southwest Texas. As a result of this surface weather pattern, our surface winds across south central Texas are south southeasterly.

In the upper levels of the atmosphere, a deep upper air low pressure trough, or north to south line of low pressure, covers the western 2/3rds of the USA with a strong disturbance embedded within the trough over the four corners region. As a result of this upper air weather pattern, the 30,000 foot winds over south central Texas are west southwesterly 35 to 45 mph.

The broad upper air low pressure trough, currently located over the western 2/3rds of the USA, has continued to contribute to a more moist and unstable air mass overhead.

We’ll continue to see scattered rain showers and thunderstorms today through tonight.. with the highest rain chances and the strongest thunderstorms remaining to our north, northwest and west.

By tomorrow into early Sunday, the strong upper level low pressure disturbance out west and the trough of low pressure overall will move northeastward into the plains states. This will allow a surface cold front to move southeastward across the IH35 corridor by tomorrow night into the predawn hours Sunday. Abundant atmospheric lift will combine with the rich low level moisture and an unstable atmosphere to produce scattered to numerous rain showers and thunderstorms particularly after mid day tomorrow through the early morning hours on Sunday. Periods of heavier rain are possible over the area.

The cold front will weaken later Sunday through Sunday night along and offshore of the Texas coast with rain chances decreasing (but not disappearing completely) locally as the front pulls up stationary in the Texas coastal waters.

By early Monday and continuing into early Tuesday, another strong upper level low pressure disturbance will approach the area from the west with the front off the Texas coast returning quickly northwestward as a warm front into our area. As the warm, moist and more unstable air mass returns and the low pressure area approaches from the west, I will quickly increase rain shower and thunderstorm chances again by early Monday and continuing into early Tuesday as another cold front sweeps eastward through the area.

As always, a reminder that lightning, associated with any thunderstorms that develop or move into the area over the next few days, will pose a danger. Updated guidance continues to suggests upwards of 1 to 3 inches of rain locally with isolated heavier amounts to over 4 inches over the next four days.

In the wake of the front, skies will partially clear as more stable, slightly cooler and drier air takes hold for Tuesday night and Wednesday into Thursday next week.

Have a good Friday….
Meteorologist Troy Kimmel

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

Updated 845am CT.. Friday / 19 May 2017

TODAY…. Morning low clouds, otherwise partly to mostly cloudy with widely scattered rain showers and thunderstorms with an associated lightning risk. A 20% chance of rain; where rainfall occurs at any given location, it will average 1/4 inch or less. High 92. South southeasterly wind 8 to 15 mph.

TONIGHT…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 30% chance of rain; where rainfall occurs at any given location, it will average 1/4 inch or less. Low 74. South southeasterly wind 8 to 15 mph.

SATURDAY…. Mostly cloudy with scattered rain showers and thunderstorms in the morning becoming more numerous in the afternoon with an associated lightning risk. A 40% chance of rain in the morning increasing to 50% in the afternoon; where rainfall occurs at any given location, it will average 1/4 inch. High 88. South southeasterly wind 8 to 15 mph.

SATURDAY NIGHT…. Cloudy with numerous rain showers and thunderstorms with an associated lightning risk. A 60% chance of rain; where rainfall occurs at any given location, it will average 1/2 to 1 inch. Low 70. South southeasterly wind 8 to 15 mph becoming more south southwesterly after midnight.

SUNDAY…. Mostly cloudy with numerous rain showers and thunderstorms with an associated lightning risk as a weak cold front moves southeastward through the area by sunrise. Rain chances decreasing midday into afternoon with the sky becoming partly to mostly cloudy. A 60% chance of rain before 8am decreasing to 20% by afternoon; where rainfall occurs at any given location, it will average 1/4 inch. High 83. Winds becoming northeasterly 5 to 10 mph as the front passes.

SUNDAY NIGHT…. Mostly cloudy and a little cooler with widely scattered rain showers. A 20% chance of rain; where rainfall occurs at any given location, it will average trace amounts. Low 64. Light northeasterly wind.

MONDAY…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 50% chance of rain; where rainfall occurs at any given location, it will average 1/4 to 1/2 inch. High 84. Light easterly wind becoming south southeasterly by late afternoon.

MONDAY NIGHT…. Mostly cloudy with numerous rain showers and thunderstorms with an associated lightning risk. A 60% chance of rain; where rainfall occurs at any given location, it will average 1/4 to 1/2 inch. Low 70. South southeasterly wind 5 to 10 mph.

TUESDAY…. Mostly cloudy with numerous rain showers and thunderstorms with an associated lightning risk as a cold front passes before 9am. Rain chances decreasing by afternoon. A 60% chance of rain before 9am decreasing to 20% by afternoon; where rainfall occurs at any given location, it will average 1/4 inch. High 84. Southerly wind 8 to 15 mph becoming northerly by midday into early afternoon.

TUESDAY NIGHT…. Mostly cloudy and a little cooler with widely scattered rain showers before midnight. Decreasing clouds after midnight becoming partly cloudy. A 20% chance of rain; where rainfall occurs at any given location, it will average 1/10th inch or less. Low 63. Northerly wind 5 to 10 mph.

WEDNESDAY…. Mostly sunny. High 80. Northerly wind 5 to 10 mph.

WEDNESDAY NIGHT…. Mostly clear. Low 59. Light northeasterly wind.

THURSDAY…. Mostly sunny. High 84. Light winds becoming southeasterly 5 to 10 mph.

NATIONAL WEATHER SERVICE / 8 TO 14 DAY OUTLOOK
Valid Friday / 26 May 2017 through Thursday / 01 June 2017…
Temperature… Slightly Below Average
Precipitation… Near Average

AUSTIN SUNSET/SUNRISE TIMES…..
Sunrise this morning (18 May)……………………………………………. 6:35 am
Sunset this evening (18 May)……………………………………………… 8:20 pm
Sunrise tomorrow (19 May)………………………………………………… 6:34 am
Sunset tomorrow (19 May)…………………………………………………. 8:21 pm