Updated 915am CT – Thursday / 18 May 2017
.. An Unsettled Weather Pattern Continues Through the Weekend ..
.. Rain and Thunderstorm Chances Come and Go ..
.. Best Rain Chances Saturday through Saturday Night into Early Sunday ..
On this Thursday… a surface low pressure area is over the area of southeastern Colorado.. northeast New Mexico.. and the Oklahoma and Texas panhandles. A cold front extends from the low into south central New Mexico into central Arizona. A cold front extends from the low pressure area east northeastward along the Kansas/Oklahoma state line then northeastward into a low pressure area over central Wisconsin. 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 east northeastward moving disturbances embedded within the trough over Lake Superior with another over central Utah. As a result of this upper air weather pattern, the 30,000 foot winds over south central Texas are southwesterly 55 to 65 mph.
The broad upper air low pressure trough, currently located over the western 2/3rds of the USA, has caused our atmosphere to become more moist and unstable.
We’ll continue to see scattered rain showers and thunderstorms today through tomorrow and tomorrow night under a partly to mostly cloudy sky even though it is difficult to find an exact triggering mechanism other than daytime heating.
By Saturday into Saturday night and into early Sunday, the next strong upper level low pressure disturbance, currently over Utah, will pass southwest to northeast over our area and will allow a surface cold front to move southeastward across the IH35 corridor by sunrise Sunday morning. 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 Saturday through the morning hours on Sunday. Periods of heavier rain are possible over the area.
The cold front will weaken later Sunday through Monday along and offshore of the Texas coast with rain chances decreasing locally as the front pulls up stationary in the Texas coastal waters.
By later Monday into Tuesday, another strong upper level low pressure disturbance will approach the area rom 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 increase rain shower and thunderstorm chances again by Monday night and Tuesday.
As always, a reminder that lightning, associated with any thunderstorms that develop or move into the area, will pose a danger. Updated guidance continues to suggests upwards of 1 to 3 inches of rain locally with isolated heavier amounts over the next seven days.
Have a good Thursday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel
—
Updated 845am CT.. Thursday / 18 May 2017
TODAY…. Morning low clouds, otherwise partly to 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. High 90. South southeasterly wind increasing to 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 73. South southeasterly wind 8 to 15 mph.
FRIDAY…. Morning low clouds, otherwise partly to 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. High 90. South southeasterly wind 8 to 15 mph.
FRIDAY NIGHT…. 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 73. 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 87. 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 before 9am. Rain chances decreasing midday into afternoon with the sky becoming partly to mostly cloudy. A 60% chance of rain before 8am decreasing to 30% by afternoon; where rainfall occurs at any given location, it will average 1/4 inch. High 83. Winds becoming light northeasterly around daybreak.
SUNDAY NIGHT…. Partly to 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 63. Light northeasterly wind.
MONDAY…. Partly to mostly cloudy with widely scattered rain showers. A 20% chance of rain; where rainfall occurs at any given location, it will average trace amounts. High 84. Light easterly wind becoming south southeasterly by late afternoon.
MONDAY NIGHT…. Mostly cloudy with scattered rain showers and thunderstorms. A 30% chance of rain; where rainfall occurs at any given location, it will average 1/4 inch or less. Low 68. South southeasterly wind 5 to 10 mph.
TUESDAY…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk. A 40% chance of rain; where rainfall occurs at any given location, it will average 1/4 inch. High 86. South southeasterly wind 8 to 15 mph.
TUESDAY NIGHT…. Mostly cloudy with scattered rain showers and thunderstorms with an associated lightning risk as a cold front passes after midnight. A 50% chance of rain; where rainfall occurs at any given location, it will average 1/4 inch. Low 66. South southwesterly wind shifting northwesterly 5 to 10 mph.
WEDNESDAY…. Widely scattered rain showers early otherwise becoming partly cloudy and a little less humid. A 20% chance of rain; where rainfall occurs at any given location, it will average 1/10th inch or less. High 83. North northwesterly wind 5 to 10 mph.
NATIONAL WEATHER SERVICE / 8 TO 14 DAY OUTLOOK
Valid Thursday / 25 May 2017 through Wednesday / 31 May 2017…
Temperature… Slightly Below Average
Precipitation… Above Average
AUSTIN SUNSET/SUNRISE TIMES…..
Sunrise this morning (17 May)……………………………………………. 6:36 am
Sunset this evening (17 May)……………………………………………… 8:19 pm
Sunrise tomorrow (18 May)………………………………………………… 6:35 am
Sunset tomorrow (18 May)…………………………………………………. 8:20 pm