Tuesday, July 30, 2013

Closing Out July Hot & Humid

By Jay Grymes & Steve Caparotta

At 3PM, Titan9 Doppler was showing some showers and a few t-storms over Washington and St. Tammany parishes as well as a few spots of rain over the southern parishes of the WAFB viewing area.  In general, our forecast for this afternoon held true: spotty showers in the viewing area with afternoon highs in the low to mid 90°s.
Get used to it.
Our forecast for Wednesday and Thursday reads like a repeat of today: morning lows in the mid 70°s, afternoon highs in the low to mid 90°s with spotty t-showers.  Most of us will stay dry over the next several days, with muggy morning starts and hot afternoons.
Yesterday we mentioned the southward advance of an upper-level trough over the eastern U.S. towards the end of the work week.  While we still expect the trough to materialize, it now looks like it might not be quite as vigorous of a surge as we initially thought.  That means its influence over the Southern Plains upper-air ridge -- which is the feature keeping us hot and mostly-dry right now -- won’t be quite as effective.  In other words, we don’t think the ridge will contract as far to the west as we thought yesterday.

The less the ridge shifts west, the greater its influence remains.  On Monday we thought we would see rain chances increase to the “scattered” category by Friday (up to around 30% or so) -- now, that doesn’t appear as likely.
For today, we’re going with “isolated” afternoon and early evening rains for Friday and right through the weekend.  We’ll keep those percentages at 20% for early next week, but that may be a bit generous -- the southern ridge may rebuild back to the east by next week, recreating a “lid” on the atmosphere and really limiting the rain potential to something closer to “spotty.”

Over the past few weeks, some WAFB communities neighborhoods have seen some big rains.  For example, this past Saturday we had reports of some neighborhoods in and around Central, Watson and northern Denham Springs getting as much as 3” to more than 5” of rain with the passing storms.  But many WAFB neighborhoods -- especially farther to the east and southeast of the greater metro Baton Rouge -- are running a bit on the “dry” side for the month.
While there is no impending drought threat in our viewing area just yet, southern and central parishes to the west of the Atchafalaya basin have been rated as “Abnormally Dry” for this time of year by the U.S. Drought Monitor.  Our forecast for the coming seven days certainly doesn’t signal any immediate relief.
In the tropics, dry air and an upper-level low just to the west of Dorian’s remnants have continued to pound the tropical wave even further today.  As a result, the National Hurricane Center at 2PM issued an outlook with “near 0% chance” of Dorian’s remnants re-developing into a tropical cyclone over the next 48 hours.  However, given that the wave still may be headed into the southeastern Gulf, we’ll keep a watch on it for you.

No comments:

Post a Comment