A Stormy Sunday?

July 5, 2014 0 Comments

Our comfy air  at the end of last week is long gone and replacing it is a much more humid and potentially hottest air mass of the season.  Highs locally were kept down Saturday thanks to clouds from a decaying thunderstorm complex that passed to our south earlier in the day.  Highs out west topped 90 degrees in most spots….that’s the air that is coming this way for Sunday,

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Slightly cooler air will come back later in the Sunday and as a result we could see a few strong to severe storms right along the cold front.  We will be under the gun after the lunch hour through the early evening with the mid afternoon the most likely time for storms to develop.

 

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Primary hazards with this round of storms will be large hail and damaging winds.  If we can escape clouds early in the day, a TON of instability will develop leading toward intense thunderstorm updrafts.

For the large hail, an intense updraft is needed to suspend water droplets high above the ground where the air is below freezing so that those droplets combine and freeze to make hail. The stronger the updraft the larger the hail.  The more instability…the stronger the updraft.

In this particular set-up there will be a lot of dry air in the middle portion of the atmosphere.  The more dry air in this level of the atmosphere, the stronger the thunderstorm downdraft will be and therefore the stronger the winds will be at the surface.  Once rain starts in the thunderstorm it will evaporate initially in this dry layer.  When water evaporates, it cools the air around it making that air more dense than its surroundings.  This air will then fall to the surface and spread out once it hits the ground.  The faster (stronger) the downdraft the faster (stronger) the winds generated by the storm will be.  The drier the air..the faster the downdraft.  The Storm Prediction Center has highlighted parts of the area in the slight risk category for severe weather.

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As with any weather event there are limiting factors.  In order to get that instability we need to have some sunshine.  This will already be an unstable air mass, but sunshine will be needed to make things even more unstable…unstable enough to create strong storms.  The same system that is coming our way is already in the process of creating clouds, rain, and storms out west.  If this eventual complex of storms (that will likely be decaying by the time it would reach us) passes through, it would prevent the sun from destabilizing the atmosphere.  If we wake up to clouds Sunday morning, the severe threat will already be diminished.   the red circle indicates the clouds and showers that could pass through in the morning.

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Stay tuned to KTTC for the latest on the potential severe threat for Sunday afternoon.

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