A More Unsettled Weather Pattern; Potential Flooding Risk Ahead (Fri/22May2020)

Audio Weather Webcast
(Includes My Complete Forecast Reasoning)
Updated Friday / 22 May 2020 ….

      
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AUSTIN / UNIVERSITY OF TEXAS
WEATHER HAZARDS THROUGH 12 MIDNIGHT TONIGHT…

.. Lighting Risk with Any Widely Scattered Thunderstorms Today into Tonight ..

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AUSTIN / UNIVERSITY OF TEXAS WEATHER
SEVEN DAY WEATHER HEADLINES…

.. Flooding Risk Increases By Late in the Weekend into Next Week ..

(1) On the heels of an enhanced south southeasterly surface wind flow, our atmosphere is growing more moist and unstable as evidenced by some early morning rain showers and thunderstorms over the past two days as disturbances pass west-to-east over our area.

(2) As we make our way through the mid and latter part of the Memorial Day weekend, there will be increasing atmospheric lift and atmospheric instability with increasing rain shower and thunderstorm activity likely. Initially, rainfall amounts potentially result in localized flooding problems especially in urban/small stream areas and low water  crossings. 

(3) By Memorial Day into Tuesday and Wednesday, a eastward moving (and weakening) cold front will move into the IH35 corridor as it loses its upper air steering currents and pulls up stationary overhead of the IH35 corridor. As this occurs, it will cause additional atmospheric lift with rain showers and thunderstorms continuing. Periods of heavier rain appear quite likely with flash flooding and river/stream flooding becoming more of a hazard.

(4) In summary, the latest NWS/Weather Prediction Center rainfall guidance suggests that the IH35 corridor and a fairly wide area from north Texas (Dallas/Ft Worth area) south southwestward to San Antonio and Laredo to Eagle Pass may see upwards of 4 to 6 inches of rain – isolated higher amounts are possible – over the next seven day period.

Remain weather aware and have at least three methods of getting weather information over the coming days. Keep in mind the National Weather Service slogan, “Turn Around and Don’t Drown,” as well. 

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Troy’s Weather Forecast for Austin and South Central Texas
Updated  Friday / 22 May 2020

TODAY…. Partly to mostly cloudy. High 92. South southeasterly wind 5 to 12 mph.

TONIGHT…. Mostly cloudy with widely scattered rain showers and thunderstorms with an associated lightning risk. A 20% chance of rain; rainfall, where it occurs, will average less than 0.25″. Low 73. South southeasterly wind 5 to 10 mph.

SATURDAY…. Partly to mostly cloudy with widely scattered rain showers and thunderstorms with an associated lightning risk. A 20% chance of rain; rainfall, where it occurs, will average less than 0.25″. High 91. South southeasterly wind 5 to 12 mph.

SATURDAY NIGHT…. Cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 20% chance of rain early increasing to 40% after 10pm; rainfall, where it occurs, will average .25″ or less. Low 72. South southeasterly wind 5 to 10 mph.

SUNDAY…. Cloudy with scattered rain showers and thunderstorms with an associated lightning risk. Periods of heavier rain possible. A 60% chance of rain; rainfall, where it occurs, will average .50″ to 1.00″. High 85. South southeasterly wind 5 to 12 mph.

SUNDAY NIGHT…. Cloudy with numerous rain showers and thunderstorms with an associated lightning risk. Periods of heavier rain possible with some flooding possible. A 70% chance of rain; rainfall, where it occurs, will average 1.00″. Low 70. South southeasterly wind 4 to 8 mph.

MONDAY /MEMORIAL DAY/…. Cloudy with numerous rain showers and thunderstorms with an associated lightning risk. Periods of heavier rain possible with some flooding possible. A 70% chance of rain; rainfall, where it occurs, will average 1.00″. High 82. South southeasterly wind 4 to 8 mph.

MONDAY NIGHT…. Cloudy with scattered rain showers and thunderstorms with an associated lightning risk. Periods of heavier rain possible with some flooding possible. A 60% chance of rain; rainfall, where it occurs, will average 1.00″. Low 70. South southeasterly wind 4 to 8 mph.

TUESDAY…. Cloudy with numerous rain showers and thunderstorms with an associated lightning risk. Periods of heavier rain possible with some flooding possible. A 70% chance of rain; rainfall, where it occurs, will average 1.00″. High 82. South southeasterly wind 4 to 8 mph.

TUESDAY NIGHT…. Cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 50% chance of rain; rainfall, where it occurs, will average 0.50″. Low 69. Light south southeasterly wind becoming light and variable late.

WEDNESDAY…. Morning low clouds then becoming partly to mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 50% chance of rain; rainfall, where it occurs, will average 0.50″. High 82. Light and variable wind.

WEDNESDAY NIGHT…. Partly to mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 30% chance of rain; rainfall, where it occurs, will average 0.25″ or less. Low 68. Light and variable wind.

THURSDAY…. Morning low clouds then becoming partly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 30% chance of rain; rainfall, where it occurs, will average less than 0.25″. High 86. Light and variable wind early becoming south southeasterly 4 to 8 mph by afternoon .

NATIONAL WEATHER SERVICE / 8 TO 14 DAY OUTLOOK          
Valid Friday / 29 May 2020 through Thursday / 04 June 2020…
Temperatures… Below Average   
Precipitation… Above Average

AUSTIN SUNSET/SUNRISE TIMES…..
Sunrise this morning (22 May)………………………………….. 6:33 am
Sunset this evening (22 May)……………………………………. 8:22 pm
Sunrise tomorrow (23 May)………………………………………. 6:33 am
Sunset tomorrow (23 May)……………………………………….. 8:23 pm

Periods of Heavier Rain and Stronger Thunderstorms Late Tonight into Early Saturday (855am Fri/15May2020)

ALL / Austin, Travis County and South Central Texas Weather Update #1
Prepared by UT University/Incident Response Meteorologist Troy Kimmel
855am CT – Friday / 15 May 2020

… Periods of Heavier Rain and a Few Stronger Thunderstorms Late Tonight into
Early Saturday Morning …

An approaching upper level low pressure storm system.. rather progressive (rather fast moving)
in nature.. will, based on the latest high resolution model guidance, produce a round of rain showers and thunderstorms for the IH35 corridor beginning around 11pm tonight continuing into the early and mid morning hours on Saturday.

At this point, the threat of severe weather looks marginal to me given the time of day – early morning hours – with the greatest risk being some marginally severe hail and straight line thunderstorm wind gusts as the leading edge of the squall line passes overhead generally around midnight and continuing for an hour or two thereafter.

The biggest risk for this event, given expected 1 to 3 inch rainfall totals (with isolated higher totals mainly east of the IH35 corridor into southeast Texas) will likely be some urban and small creek flooding in the more urban IH35 corridor areas with flash flooding possible mainly to our south and southeast where heavier rainfall totals upwards of up to 6 inches or more fell last Tuesday.

The good news is that the timing of the system means that there will be less traffic on roadways as most of the system passes. As a result, as long as we are responsible and remember the NWS slogan, “turn around, don’t drown,” the effects should be something we can negotiate safely. Remember, failing to observe flooding safety rules means that we might have to put our first responders lives at risk as the result of a bad personal decision.

I’ll continue to monitor..

Have a good weekend, all!
tk

Reminders…
I encourage everyone to be weather aware. Know, in advance, the difference between a
NWS issued WATCH, ADVISORY and WARNING.

 

Always have at least two methods of getting current weather information..
.. follow me AND activate notifications on Twitter .. @troykimmelwx ..
.. have your NWS All Hazards Weather Radio properly set so it can receive and activate
when NWS watches and warnings are issued ..
.. register to receive emergency updates at https://warncentraltexas.org/
.. make sure the WEA alerts are activated in your settings on your smart phone ..
.. go to the NWS Austin-San Antonio website at weather.gov/ewx ..
.. go to http://mesonet.agron.iastate.edu/cgi-bin/afos/retrieve.py?pil=warewx&limit=20&fmt=html
for a chronological text listing (most current at the top but note the page doesn’t auto-refresh, you must refresh page manually) of NWS Austin-San Antonio watches, advisories and warnings..