This has not been a typical Louisiana summer where we see tropical waves rotate around the Bermuda high with windflow coming from the SE off the Gulf. Most of this summer, the Bermuda High/Atlantic Ridge has been depressed far down into the Gulf with mainly a westerly wind flow across the northern Gulf. Our storms have been coming down from the north as disturbances rotate around an upper high centered near Dallas. This pattern has allowed several frontal boundaries drift down off our coast and another such boundary will sag thru on Friday bringing slightly drier air. I do not expect to see a repeat of late PM storms like the past 2 days. What we need to monitor is whether low pressure tries to develop as the frontal boundary pushes deeper into the central Gulf. Hurricane Alicia formed from an old frontal boundary in mid August 1983. August 1st is Saturday, time to pay attention to the Tropics. Friday & Saturday look hot & mostly dry with perhaps a few more storms returning for Sunday PM. Stay Tuned!
Wednesday, July 29, 2015
Our typical summer day would have morning sunshine bubble up scattered showers and storms by 11-12 noon. That helps keep afternoon temps in check. This July has seen an absence of daily showers resulting in highs soaring to near 100 degrees. Today was such a day as we set new records at MSY (99) & Audubon Park (1001). Fortunately several clusters of late afternoon storms arrived to really cool us off. 1-3”+ totals drenched both sides of the Lake. Algiers almost had 5” (4.74”). Hopefully we’ll see a repeat again on Thursday and Friday as the upper high that has been keeping us dry retreats farther to the west.
A swirl of clouds has moved off of Africa and NHC is giving it a chance of developing into something before it encounters cooler waters & stronger shear later this week. I don’t track activity that far out in the Atlantic. More likely our next named storm will be along the Georgia/ Carolinas coast. Stay tuned!
Tuesday, July 28, 2015
Computer models have a difficult time dealing with the lower latitudes in summer. The subtle changes are often missed even on the higher resolution models. The past 24 hours is a classic example. Yesterday evening the models seem to have latched on to the idea of low pressure developing well south of the Louisiana coast later this week. As it moved farther to the west, we would get on the “wet side” giving us higher rain chances later this week. Tonight’s runs are totally different. No closed low forms and moves to the west. The deep Gulf moisture stays well to our south along an old frontal boundary and we stay very hot & mostly dry. Go figure. I often only use the 24 hour model run as anything beyond that has a high degree of uncertainty. Yet I see on every channel weathercasters showing the models out to 48 hours & beyond. That’s OK as long as one mentions the degree of uncertainty in the summer.
So let’s take a stab at Wednesday. From what I’m seeing on satellite & radar loops, the upper high that has kept us mostly dry is shrinking back to the west. Disturbances are rotating around the high and one such might arrive here late in the afternoon (5-8 PM). It could bring heavy downpours, gusty winds to 40+ & briefly cooler temperatures. Let’s hope our daily storms return so we don’t have to deal with the “extreme heat”! Stay tuned!
Monday, July 27, 2015
Since it appears the deep dust layer coming off of Africa, combined with the shearing winds of a strong El Nino, should result in near zero long tracked storms across the Caribbean this summer. More likely we’ll see closer in along old frontal boundaries that sag off the east coast ong dip into the northern Gulf. One such boundary is over the NE Gulf tonight and satellite & radar loops are showing a weak area of low pressure NW of Tampa. Neither our VIPIR model nor the RPM & GFS models show much development during the next 1-2 days. Still it’s the area we will watch since it’s so close to home. For the time being, an upper high will block any motion towards us keeping us very hot & mostly dry. That pattern should break down by later in the week making us less hot with more cooling showers.