Monthly Archives
April 2017

Troy’s Special Briefing (110am CT Sun/30Apr2017)

by troyk | on Apr 30, 2017 | Comments Off

Austin / Travis County and South Central Texas Weather Update #8 – FINAL
Prepared by UT University/Incident Meteorologist Troy Kimmel
110am CT – Sunday / 30 April 2017

.. Another Round of Rain Showers and Thunderstorms Over the Next Few Hours ..
.. Severe Weather Not Anticipated ..

At 110am this Sunday morning.. an upper air disturbance is moving eastward out of west Texas with
scattered rain showers and thunderstorms spreading eastward into the IH35 corridor. Severe
weather is not anticipated; occasional deadly lightning along with the possibility of some small hail
will occur as these thunderstorms move through our area between now and 5am. As this disturbance
moves through, gusty northerly winds will increase as the cold front continues its move off the
Texas coast.

There are no longer any watches in effect for our local area.

Along the IH35 corridor, in summary, we had few small hail reports early Saturday evening but the
reports were sub-severe. It looks like cooler, much drier and more stable air will take hold over the
area today in the wake of this last upper air disturbance. We’ll take the break in the weather and the
sunshine later today into Monday and Tuesday before another upper level low pressure storm system
and associated cold front takes aim on Texas with the chance of thunderstorms by mid into late week.

In closing, I will mention the deadly round of tornadoes over areas to our distant northeast around
Canton (Van Zandt County) last evening – with a death toll of at least five, dozens injured and severe
property damage (including a former student of mine that had considerable damage loss to the family
farm he has worked so hard on – but everyone is OK – we’ve talked through the evening). Let’s just
remember our first responders.. local, state and even federal.. from throughout Texas that have been
dispatched to that community to help in search and rescue operations as we comfortably sleep.

Just a reminder to remember that this is our severe weather season.. always be weather aware!

This is my final statement on this weather situation.

tk

Troy’s Special Briefing…. (145pm CT Sat/29Apr2017)

by troyk | on Apr 29, 2017 | Comments Off

Austin / Travis County and South Central Texas Weather Update #2
Prepared by UT University/Incident Meteorologist Troy Kimmel
145pm CT – Saturday / 29 April 2017

.. Enhanced Severe Thunderstorm Risk Continues This Afternoon into Tonight
with Cold Frontal Passage ..

At 200pm.. the warmer, more stable air aloft – referred to as a “temperature
inversion” – continues to hold strong across the area as the cold front/dry line continues
to progress east southeastward along a line from Durant, OK southwestward to
about 40 miles west of the DFW metroplex to just west of Hamilton, TX to northeast
northeast of Junction where it intersects with a surface dry line that extends southward
to west of Del Rio. At this time, because of the more stable air aloft, we’re seeing little
in the way of precipitation along and ahead of the front.

Temperatures, ahead of the front over central and north Texas, are approaching
90 degrees along the IH35 corridor from San Antonio through Austin northward to the
DFW metrplex while immediately behind the front the temperatures fall into the
50s and 60s. Temperatures over the Texas panhandle are in the 30s and 40s.

The real question is… when are the thunderstorms to develop along the front? There’s
little question in my mind that they will, but they’re already a bit behind my schedule I
set in the last update. I feel that when they do, which will come with weakening and
removal of the inversion, there will be quite a bit of energy released and the development
should be fairly rapid.

Let’s continue to be “weather aware” and to listen to the latest updates from the
National Weather Service…. I’ll keep you advised.

tk

Troy’s Special Briefing… (1120am CT Sat/29Apr2017)

by troyk | on Apr 29, 2017 | Comments Off

Austin / Travis County and South Central Texas Weather Statement #1
Prepared by UT University/Incident Meteorologist Troy Kimmel
1120am CT – Saturday / 29 April 2017

.. Enhanced Severe Thunderstorm Risk This Afternoon into Tonight with Cold Frontal Passage ..

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

NWS WATCHES / ADVISORIES / WARNINGS:
There are no current NWS watches, advisories and/or warnings in effect for our IH35
corridor counties..
Based on the NWS/Storm Prediction Center outlook, I feel as though a severe weather watch,
from the NWS/Storm Prediction Center, is likely for parts or all of our area between 3pm today
and 9pm tonight as the dynamics (atmospheric instability and lift), associated with a passing
upper air low pressure area and a rather strong surface cold front, increase and peak over our area.


SYNOPTIC/FORECAST REASONING:
A strong upper level low pressure area and an associated cold front will move from west to
east across the area later today into early tonight. The best dynamics (instability and lift) will
be overhead and to our north.

Current NWS/Weather Prediction Center rainfall guidance suggests that rainfall should remain in
the 1/2 to 1 inch range.. therefore the risk of any flooding is very low. Urban and small stream
flooding is possible during the periods of heavier rain over these respective areas.

The cold frontal passage will occur locally by early evening tonight with any severe
weather risk and rain chances diminishing thereafter.

THREAT(S) FOR AUSTIN METRO AND IH35 CORRIDOR COUNTIES:
Severe weather threat probability
Geographic area: The IH35 corridor of south central Texas
Time Period: 4pm today to 10pm tonight
Main severe weather hazards expected:
Larger hail.. potential of strong straight line thunderstorm wind and isolated tornadoes…
***REMEMBER, DANGEROUS CLOUD-TO-GROUND LIGHTNING SHOULD BE EXPECTED
TO OCCUR WITH ANY THUNDERSTORMS THAT DEVELOP OR MOVE INTO OUR AREA***

MY FORECAST CONFIDENCE:
Weather system evolution: Very high
Precipitation chances: High
Liquid precipitation (rain) chances: High
Thunderstorm/lightning chances: High

Flash flood potential: Very Low to Low
Severe thunderstorm chances: ENHANCED 
(Main risks being large hail.. straight line thunderstorm wind and isolated tornadoes)
Freezing precipitation (freezing rain/freezing drizzle) chances: None
Frozen precipitation (snow/ice pellets-sleet) chances: None


LATEST OBSERVATIONS AND MY THOUGHTS:

At 1100am, the surface cold front extends from east of Tulsa, OK southwestward
to near Sherman/Denison, TX (and then to about 60 miles west of the DFW Metroplex)
to near Brownwood then to near Sonora and to west of Del Rio and then into Mexico.
Temperatures have warmed into the 80s (and dew points in the 60s to near 70 degrees F)
ahead of the front with temperatures falling back in the 50s in the wake of the front at
Wichita Falls and Abilene with the 40s over the panhandle. At 1100am, there is little in
the way of precipitation immediately ahead of the front as the result of a layer of warmer,
more stable air aloft (referred to as a “temperature inversion”).
Short range high resolution data suggests that this “temperature inversion” will be overcome
by increased atmospheric lift and daytime heating in the next hour or two and, as a result,
a broken north to south line of thunderstorms will quickly develop over north Texas in the
next hour or two and move eastward; as it does, the line will develop further southward
through central Texas with the guidance suggesting that the thunderstorms make their closest
approach locally with the frontal passage locally around 5 to 6pm. The guidance suggests that
the line will further solidify well southward once it passes the Austin area and the IH35 corridor
by early evening. Given this current scenario, it is possible that some people west of the IH35
corridor may not even receive any rainfall while other areas, primarily to the east of the IH35
corridor will see the stronger thunderstorms and the heavier rains. This system will be quite
progressive.. that is, it will move steadily through the area.. so the time period for thunderstorms
will remain fairly short for any given location.


AVIATION INFORMATION FOR THE AUSTIN/BERGSTROM
INTERNATIONAL AIRPORT (KAUS) AERODROME:

There is a ENHANCED large hail.. strong straight line thunderstorm wind.. and
isolated tornado threat this afternoon into tonight. Scattered to numerous
rain showers and thunderstorms will affect the AUS aerodrome as the cold front
passes by early evening. Deadly cloud-to-ground lightning will accompany
thunderstorms. The thunderstorm/rain chances slowly decreasing after 10pm
tonight…

Current KAUS Terminal Aerodrome Forecast (TAF) – Updated 291532z ..

FTUS44 KEWX 291532 AAA
 TAFAUS
 TAF AMD
 KAUS 291532Z 2916/3018 15014G24KT P6SM BKN025 BKN035
      FM291700 16016G26KT P6SM VCSH BKN035
      FM300100 34018G28KT P6SM SHRA BKN035
       TEMPO 3001/3004 TSRA SCT010 BKN035CB
      FM300600 34012KT P6SM FEW025 BKN070
      FM301500 29014KT P6SM FEW090=

. For Our DAL/DFW Hub Aerodromes ..
… Delays / Diversions Likely This Afternoon into this Evening …
Current NWS public forecasts indicates a 70% chance of rain showers and
thunderstorms this afternoon diminishing slowly to 60% tonight. There is a SLIGHT to
ENHANCED risk of severe thunderstorms this afternoon with larger hail.. strong
damaging straight line thunderstorm winds and isolated tornadoes. The cold front, with
associated wind shift (and airport approach/departure “turn around”) is forecast to move
through the aerodromes by mid afternoon. Given this scenario, it is likely that we’ll see
at least some delays and diversions from individual aerodromes and the ZFW center air
space as the strongest thunderstorms affect the area through early this evening.

For Our HOU/IAH Hub Aerodromes ..
… Delays / Diversions Possible Late Tonight and Again First Thing in the Morning …
Current NWS public forecasts indicates a 20% chance of rain showers and
thunderstorms this afternoon.. increasing to 40% by 9pm tonight.. then
increasing to 70% after midnight tonight and continuing through the overnight hours
with rain chances decreasing by daybreak tomorrow.
There is a SLIGHT risk of severe
thunderstorms later tonight into the 4am time period tomorrow with larger hail.. strong
damaging straight line thunderstorm winds and isolated tornadoes.
The cold front is
forecast to cross the IAH and HOU aerodromes in the 3am to 4am time frame early
tomorrow. Even though this is a quieter operational commercial aircraft period for the
aerodromes, there is still a possibility of delays and diversions from individual aerodromes
and the ZHU center air space overnight tonight as the upper air low pressure system
and front moves across Texas.

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.

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, please let me know at tkimmel@austin.utexas.edu

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 Apr 28, 2017 | Comments Off

Updated 915am CT – Friday / 28 April 2017

.. A Stronger Cold Front with a Chance of Thunderstorms by Late Saturday ..
.. Cooler Temperatures Sunday into Monday ..

On this Friday… a northeastward moving warm front extends southeastward from a surface low pressure area over west central Texas through east Texas into Louisiana and southern Mississippi. A cold front extends from the low pressure area through west Texas and west central New Mexico. As a result of this surface weather pattern, our surface winds across south central Texas are southerly.

In the upper levels of the atmosphere, a deep trough.. or line of upper level low pressure.. extends southward from central and western Canada through the western 2/3rds of the USA. As a result of this upper air weather pattern, the 30,000 foot winds over south central Texas are west southwesterly 55 to 65 mph.

Surface winds have returned back southerly with low level moisture quickly returning to the area.

As a dynamic area of upper air low pressure moves eastward through the southwestern USA into the southern and central plains by late tonight into tomorrow, a stronger area of surface low pressure and associated cold front will advance quickly into Texas. The cold front will pass through the local area late Saturday night. With abundant low level moisture in place along with instability and atmospheric lift accompanying the system, the latest guidance from the NWS/Storm Prediction Center suggests prefrontal thunderstorms over the area with stronger, potentially severe, thunderstorms mainly in areas to our north over north and east Texas and Oklahoma and areas eastward.

A drier.. more stable and a cooler air mass will move into Texas in the wake of the front for most of the day Sunday through Sunday night into early next week.

Another low pressure area and cold front will progress southeastward across the area late next Wednesday with another chance of rain showers and thunderstorms. Slightly cooler and drier air will advance into the area again by Wednesday night into Thursday.

Have a good Friday….
Meteorologist Troy Kimmel

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

Updated 845am CT.. Friday / 28 April 2017

TODAY…. Becoming partly cloudy. Unseasonably warm with a high of 92. Southerly wind 8 to 15 mph with higher gusts.

TONIGHT…. Partly cloudy early becoming cloudy late. Low 75. Southeasterly wind 5 to 12 mph.

SATURDAY…. Morning low clouds.. otherwise partly to mostly cloudy with scattered afternoon rain showers and thunderstorms with an associated lightning risk. A 30% chance of rain; rainfall, where it occurs, will average 1/4 inch or less. High 89. Southerly wind 8 to 18 mph with some higher gusts.

SATURDAY NIGHT…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 60% chance of rain; rainfall, where it occurs, will average 1/4 inch. Low 59. South southeasterly wind 8 to 15 mph with some higher gusts.. winds becoming more southwesterly after midnight then northwesterly toward daybreak as a cold front passes.

SUNDAY…. Mostly cloudy with widely scattered rain showers and thunderstorms before 7am with an associated lightning risk. A 20% chance of rain; rainfall, where it occurs, will average 1/4 inch or less. Clearing.. less humid and a little cooler after mid morning. High 75. Northwesterly wind 8 to 15 mph with some higher gusts.

SUNDAY NIGHT…. Clear and unseasonably cool. Low 50. North northwesterly 5 to 10 mph.

MONDAY…. Sunshine. High 80. Northerly wind 5 to 10 mph becoming more east northeasterly by afternoon.

MONDAY NIGHT…. Clear. Low 58. Light easterly wind.

TUESDAY…. Sunny and warmer. High 86. Southerly wind increasing to 5 to 12 mph.

TUESDAY NIGHT…. Becoming mostly cloudy. Low 67. South southeasterly wind 5 to 12 mph.

WEDNESDAY…. Morning low clouds.. otherwise partly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 30% chance of rain; rainfall, where it occurs, will average 1/4 inch. High 85. Southerly wind 8 to 15 mph.

WEDNESDAY NIGHT…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk as a cold front passes. A 30% chance of rain; rainfall, where it occurs, will average 1/4 inch. Decreasing clouds after 2am. Low 59. Southwesterly wind shifting northwesterly 8 to 15 mph.

THURSDAY…. Mostly sunny. High 77. North northwesterly wind 5 to 12 mph.

NATIONAL WEATHER SERVICE / 8 TO 14 DAY OUTLOOK
Valid Friday / 05 May 2017 through Thursday / 11 May 2017…
Temperature… Near to Slightly Below Average
Precipitation… Slightly Below Average

AUSTIN SUNSET/SUNRISE TIMES…..
Sunrise this morning (28 Apr)……………………………………………. 6:50 am
Sunset this evening (28 Apr)……………………………………………… 8:07 pm
Sunrise tomorrow (29 Apr)………………………………………………… 6:49 am
Sunset tomorrow (29 Apr)…………………………………………………. 8:08 pm

by troyk | on Apr 27, 2017 | Comments Off

Updated 915am CT – Thursday / 27 April 2017

.. Another Sunny Day Ahead ..
.. A Stronger Cold Front with a Chance of Thunderstorms by Late Saturday ..
.. Cooler Temperatures Sunday into Monday ..

On this Thursday… an eastward moving cold front extends from the Great Lakes to along the Mississippi/Alabama state line then into the northwestern Gulf of Mexico off the Texas coast. Surface high pressure is located over east Texas. A deepening trough, or line, of low pressure extends southward through eastern Wyoming through eastern Colorado into eastern New Mexico and far west Texas. As a result of this surface weather pattern, our surface winds across south central Texas are light north northwesterly.

In the upper levels of the atmosphere, a deep trough.. or line of upper level low pressure.. is moving eastward over the central part of the USA. As a result of this upper air weather pattern, the 30,000 foot winds over south central Texas are westerly at 70 to 80 mph.

In the wake of the front last evening, we’ve seen a change to drier and more stable air. This will be very temporary as the front returns back north northwesterly over the area by later today into tonight as surface winds pick back up from the south with low level moisture quickly returning to the area.

As a dynamic area of upper air low pressure moves eastward through the southwestern USA into the southern and central plains by late tomorrow into Saturday, a stronger area of surface low pressure and associated cold front will advance quickly into Texas. The cold front will pass through the local area Saturday night. With abundant low level moisture in place along with instability and atmospheric lift accompanying the system, the latest guidance from the NWS/Storm Prediction Center suggests prefrontal thunderstorms over the area with stronger, potentially severe, thunderstorms mainly in areas to our north over north Texas and Oklahoma and areas eastward.

A drier.. more stable and a cooler air mass will move into Texas in the wake of the front for most of the day Sunday through Sunday night into early next week.

Another low pressure area and cold front will progress southeastward across the area late next Wednesday with another chance of rain showers and thunderstorms. Slightly cooler and drier air will advance into the area again by Wednesday night into Thursday.

Have a good Thursday….
Meteorologist Troy Kimmel

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

Updated 845am CT.. Thursday / 27 April 2017

TODAY…. Mostly sunny. High 86. Wind becoming south southeasterly wind 5 to 12 mph.

TONIGHT…. Mostly clear early with clouds increasing late. Low 68. South southeasterly wind 5 to 10 mph.

FRIDAY…. Becoming partly cloudy. Unseasonably warm with a high of 93. Southerly wind 8 to 15 mph with higher gusts.

FRIDAY NIGHT…. Partly cloudy early becoming cloudy late. Low 75. Southeasterly wind 5 to 12 mph.

SATURDAY…. Morning low clouds.. otherwise partly ro mostly cloudy with scattered afternoon rain showers and thunderstorms with an associated lightning risk. A 30% chance of rain; rainfall, where it occurs, will average 1/4 inch or less. High 89. Southerly wind 8 to 18 mph with some higher gusts.

SATURDAY NIGHT…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 50% chance of rain; rainfall, where it occurs, will average 1/4 inch. Low 60. South southeasterly wind 8 to 15 mph with some higher gusts.. winds becoming more southwesterly after midnight then northwesterly toward daybreak as a cold front passes.

SUNDAY…. Mostly cloudy with widely scattered rain showers and thunderstorms before 7am with an associated lightning risk. A 20% chance of rain; rainfall, where it occurs, will average 1/4 inch or less. Clearing.. less humid and a little cooler morning through the afternoon. High 75. Northwesterly wind 8 to 15 mph with some higher gusts.

SUNDAY NIGHT…. Clear and unseasonably cool. Low 50. North northwesterly 5 to 10 mph.

MONDAY…. Sunshine. High 80. Northerly wind 5 to 10 mph becoming more east northeasterly by afternoon.

MONDAY NIGHT…. Clear. Low 58. Light easterly wind.

TUESDAY…. Sunny and warmer. High 86. Southerly wind increasing to 5 to 12 mph.

TUESDAY NIGHT…. Becoming mostly cloudy. Low 67. South southeasterly wind 5 to 12 mph.

WEDNESDAY…. Morning low clouds.. otherwise partly cloudy with scattered rain showers and thunderstorms with an associated lightning risk as a cold front passes by late afternoon. A 30% chance of rain; rainfall, where it occurs, will average 1/4 inch. High 85. Southerly wind shifting northwesterly 8 to 15 mph.

NATIONAL WEATHER SERVICE / 8 TO 14 DAY OUTLOOK
Valid Thursday / 04 May 2017 through Wednesday / 10 May 2017…
Temperature… Near to Slightly Below Average
Precipitation… Near Average

AUSTIN SUNSET/SUNRISE TIMES…..
Sunrise this morning (27 Apr)……………………………………………. 6:51 am
Sunset this evening (27 Apr)……………………………………………… 8:06 pm
Sunrise tomorrow (28 Apr)………………………………………………… 6:50 am
Sunset tomorrow (28 Apr)…………………………………………………. 8:07 pm