Thursday, May 24, 2012

By Jay Grymes & Steve Caparotta

There are three weather stories to discuss as we head towards the extended Memorial Day weekend.

The first is the local forecast for summer-like heat. The upper-level ridge of high pressure that has kept northern Mexico and much of Texas hot and mainly-dry for the last couple of days continues to expand and shift towards the lower Mississippi Valley. As you recall, upper-air ridging typically puts a clamp on cloud development -- not only means little or no afternoon showers activity but also allowing more sunshine to add to the daytime heating. Plus, ridging aloft further adds to the warmth because it generates sinking air, and sinking air must warm as it descends.

The bottom line: it’s going to be HOT! So, for how long? We expect ridging to dominate the Bayou State weather through Monday, at least. This is good news for many, as it means dry days for the long weekend and the “unofficial” start of summer. For a few others, however, “hot and dry” means time to start thinking about watering the gardens and landscaping.

Don’t be surprised to see some mid 90°s around the region and posted by our WAFB Weather Watchers between Saturday and Monday! But you’ll notice we keep the low 90°s in play through the entire 7-day outlook. We’ll add in slight mainly-afternoon rain chances towards the latter part of next week, but nothing to warrant a heat-breaking trend anytime soon!

The other two weather stories deal with the tropics.

The NOAA hurricane specialists have issued their 2012 Hurricane Outlook today, calling for 9-15 ‘named storms,’ with 4-8 of those becoming hurricanes and from 1-3 of those hurricanes becoming ‘major’ storms. In general, their forecast leans towards something near the long-term norm for the Atlantic Basin ... not surprising and not too different from the general forecasts we’ve shown for several other hurricane prognosticator teams. Note that this forecast calls for activity far below what we saw in 201 and 2011, when both seasons tallied 19 ‘named storms.’

Our interest has returned to the tropical satellite loops this afternoon. Although it is still far too early to call for certain development, the elongated area of low pressure that was in the western Caribbean on Tuesday and Wednesday has moved north and appears to be centered somewhere near the eastern Florida Keys as of this afternoon. With pressures falling and some evidence of broad circulation, the National Hurricane Center has upped the chance for development to about 4-in-10 over the next two days. The most likely region for the low to develop would be over the warm Gulf Stream waters somewhere east of Florida and north or northwest of the Bahamas.

Under typical circumstances for May, a tropical system off the Florida Atlantic Coast would be no big deal for interests along the central Gulf Coast. But there is one ‘hook’ this go around: the upper-level ridge that is going to heat us up over the coming days is expected to continue to shift eastward over the long weekend. If it gets positioned to the north of this western Atlantic low, it could cause the system to stall and begin a westward track. Indeed, that is what the NWS extended surface outlook is suggesting, with the low moving into the northeastern Gulf and possibly into the Florida Panhandle by Monday or Tuesday.

There are a stack of “ifs” tied to this extended tropical outlook, but this Florida low certainly bears watching in the coming days, especially if you are headed to Florida for the long weekend!

If you're staying around BR, maybe you're headed to the Bayou Country Superfest!  Great music .. but HOT!  Be prepared for the sunshine and prolonged heat!

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