Thursday, March 7, 2013

Warming Trend into the Weekend

By Jay Grymes & Steve Caparotta


We expected another cold morning, but Metro Airport briefly slipped to 32°, a few degrees colder than expected.  Temps rebounded nicely through the morning and mid-day, but a deck of high clouds moved over the area during the afternoon, slowing the afternoon warm-up.  Satellite trends suggest that those clouds should exit to the east later this evening and overnight, allowing for mainly fair skies after midnight and into the morning on Friday.

Currently there is a large surface ridge of high pressure extending from the Great Lakes to the Gulf.  That elongated high will ease its way east over the next couple of days, allowing our winds to swing around to the east and southeast through the day on Friday.
Plan on a chilly start for Friday, with sunrise temps near 40° for much of the metro area.  Clouds will slowly increase through the day, with partly cloudy skies for the afternoon becoming mostly cloudy later in the day.  Friday will be warmer too, starting a 3-day run with highs in the 70°s.  Saturday will be the better “outdoor” day for the weekend, under a sun/cloud mix.
A storm system off the California coast today will starts its march eastward over the coming days.  It should be spinning over the U.S. “Four Corners” region tomorrow and head into the Southern Plains by early Saturday.  As we mentioned yesterday, the core of the storm will remain to our north with its attendant cold front extended southward.  That front is expected to be draped over eastern Texas by Sunday morning and is scheduled to sweep into southeast Louisiana by Monday morning.

The first of the pre-frontal rains will begin to show-up on Titan9 Doppler radar by Sunday afternoon, with rain chances rising through the remainder of Sunday as the front draws near.  For now, we’re posting a 30% rain chance for late Sunday afternoon, with those chances rising to 70% to 80% by late Sunday into early Monday morning.
The extended outlook from the NWS Weather Prediction Center (WPC) still indicates 0.5” to 1.0” of rain for the WAFB viewing area.  We do expect thunderstorms with the front’s approach and passage, but we still aren’t seeing this as a widespread severe weather event.
The front should move through fairly quickly, with clearing during the latter half of Monday.  The outlook for the rest of the work week looks “dry.”

We continue our review of severe weather threats during “Severe Weather Awareness Week.”  Lightning may well be the most under-rated weather threat of them all, and the threat is especially high for the Bayou State:
-- there have been roughly two dozen LA lightning deaths over the past 20 years, including a couple of fatalities in recent years right in the Baton Rouge area;
-- metro Baton Rouge averages 70-75 thunderstorm days per year, and while the threat is greatest in summer, thunderstorms occur year-round throughout the Gulf Coast region; and
-- at a frequency of nearly 20 cloud-to-ground flashes per square mile each year (based on analysis by the National Lightning Detection Network), Louisiana ranks #2 behind Florida in terms of lightning strikes . . . and southeast Louisiana is the most dangerous region within the state. (For our SW Mississippi viewers, Mississippi ranks #3).

The vast majority of Louisiana lightning fatalities and injuries occurred to those outdoors that failed to take action when the lightning threat developed.  And keep in mind, the greatest threat from lighting -- what catches many victims off-guard -- is that is does not have to be raining for lightning to strike. 

Here’s the simple rule: if you can see lightning or hear thunder, you are potentially in harm’s way.  And the best way to reduce the threat?  Just go indoors!

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