KATC StormTeam 3 Weather BLOG

In the midsth of an increasingly busy hurricane season the threats to the Gulf of Mexico so far have been minimal.  We have been fortunate that a relative strong upper ridge has been persistent across the northern Gulf over the last several weeks while upper level low pressure troughing along the east coast of the U.S. has turned the recent storms away from the Gulf. 

Climatologically speaking, the prime-time weeks for major hurricane threats in the Gulf of Mexico are generally from the last week of August through the first week of October.  Based on the current and future weather pattern it appears that two of those weeks will be crossed out for Acadiana with no major storm threats expected through the Labor Day Weekend.  That leaves the 3 week period from mid-September onward that climatology dictates we will see more big storms.

The pattern will likely change however with models indicating a deep easterly flow developing across the Caribbean and into the Gulf.  While the models do not show any major overt storm development in the 10-14 day time frame, it does not mean that we won’t have any threats.   I would expect the pattern  to shift to more tropical genesis near the Caribbean by the second week of September all the while as robust disturbances continue to roll off the African coast.

In the near tern, unfortunately major Hurricane Earl’s forecast track issued by the National Hurricane Center has shifted a little farther to the west today putting the Mid-Atlantic U.S. to New England and the Canadian Maritimes at greater risk for damaging conditions later this week.  Hurricane watches for the North Carolina Coast have been issued with the 400pm update today.

Meanwhile Fiona is very close on the heals of Earl and may become a victim of the Fujiwhara Effect that makes Earl the dominant storm while Fiona or the future remnants fighting to survive and possibly “dumb-belling” north and northeastward keeping Fiona well away from land.  In addition to more hostile upper winds, cooler water upwelled from Earl should keep Fiona a marginal tropical storm over the next several days.

We’ll be watching Earl for our East Coast friends but we will be at least able to enjoy the extended weekend without any tropical worries close to home.

We are now at that time of year when the tropics ramp up quickly as robust tropical waves that come off of the African Coast, near the Cape Verde Islands, have increased potential for hurricane development. 

Danielle was the first this year with another candidate looking to become “Earl” before the week is done. 

All indicators for an active tropical season remain present, including very warm ocean temperatures, lower than normal tropical surface pressures, and favorable upper level winds associated with La Nina. 

There remain two “wild cards” as we have mentioned over the last several weeks…dry Saharan air with dust has been a storm “mitigator” over the last several weeks, and probably has had impact on Danielle today.  This dust should become less of a factor over the next week or two as more regular and wetter waves traverse the southern Saharan Desert.

The second wild card: upper level lows, that present interupting shear, have also inhibited some development so far this summer.  These upper lows have been theorized to be more robust and numerous in hotter summers. 

There is no indication one way or another whether these features will continue to be a factor as we head into the heart of hurricane season.

Factoring all the variables, it is still expected that on average we will likely be talking about 1-2 tropical systems per week through at least the second week of October.  How many of these systems will threaten the Gulf of Mexico and the East Coast of the U.S. remains to be seen.

In the near term and closer to home, deep tropical moisture will be pooling along a decaying frontal boundary in the Western Gulf of Mexico through the end of the week.  This moisture should bring higher rain chances and the threat of soaking rains back to Acadiana just in time for the weekend.

It promises to be a rather wet week for most of Acadiana as we continue to deal with the remnants of TD5 as it drifts westward toward Acadiana  Tuesday and the northward Wednesday.   A FLOOD WATCH has been posted for portions of Acadiana from Tuesday morning through Wednesday in the anticipation of the heavy rain threat.

 As expected over the weekend this remnant system persisted across the interior portions of the Gulf States and then dropped back to the south with the circulation getting back out over open Gulf water late Sunday night.

Hurricane Hunters flew this system Monday afternoon just south of Mobile, Alabama.  The reconnaissance plane found broad low pressure, like last week, but disorganized thunderstorm activity near the center, like last week.  This time around upper level conditions are a little more favorable for development through Tuesday prior to the circulation making landfall over Eastern Louisiana Tuesday afternoon.  If thunderstorms cluster near the center of circulation later tonight it will likely become an “official” tropical system

Based on upper level conditions and broad lower surface pressures this system is very close to being a depression and may become one at any time through tomorrow.  If the system is upgraded, tropical storm warnings would probably be issued for portions of Louisiana through the Alabama coast.

The bottom line with this system is that it will be a major rain-maker with rainfalls of 3-5″ likely around this system and up to 8-10″ possible near where the center of circulation travels through mid-week.  Rainfall totals will likely be directly correlated to the speed, or lack of, this exhibits over the next few days.  Most computer models earlier today indicated the greatest threat of flooding rains will be in the eastern part of the state Tuesday and then the central part of the state Tuesday night into Wednesday. 

More recent computer model runs this evening are much more robust with rainfall totals in Acadiana with  3-5″  possible through Thursday with isolated spots receiving possibly more than double depending ultimately where the center of circulation goes and how quickly it moves.  Stay with KATC and katc.com for the latest information.

The remnants of TD5 and a broad area of low pressure continued to linger across Southern Mississippi and Alabama Friday afternoon.  This system is expected to meander across the northern Gulf States through the weekend with computer models insisting that the remnant circulation will drift back to the south by early next week and then westward through mid-week. 

Interestingly enough, some of the models actually intensify the low as it drifts westward across the Louisiana coast during the Tuesday/Wednesday time-frame.  While this is rather unusual, other poorly organized remnant systems sealed in an almost purely tropical environment have done this in the past with previous systems actually slowly strengthening over land, and near water, across the Yucatan, Florida, North Carolina and Texas…most memorable being Tropical Storm Allison in 2001. 

The bottom line for us in Acadiana is that we may see better rain chances and something a little more for mid-next week.  Meandering systems almost always make for “forecast busts” so stay with KATC and katc.com for the latest over the weekend…

An area of disturbed weather off of the SW coast of South Florida Monday promises to bring active tropical showers and thunderstorms to Acadiana by Thursday.  Tropical models do not show much in the way of robust development but hostile upper level winds could relax in time just as this system approaches coastal Louisiana by late Wednesday into early Thursday. 

Our in house high resolution computer model, FutureCast, shows modest surface development to a tropical depression or weak tropical storm status Wednesday into Thursday as this system moves westward and then possibly northward. 

The bottom line: expect a good soaking, perhaps some blustery winds, and perhaps a named tropical system knocking on Acadiana’s door by Thursday so stay with KATC and katc.com for the latest.