KATC StormTeam 3 Weather BLOG

Our rain chances should begin to drop after Thursday as the upper level Texas trough begins to weaken and starts lifting to the north-northeast. This should allow for one more day of enhanced rain chances with the deepest moisture conduit shifting back to the west. Drier more stable air in the Gulf of Mexico and to the west of Tropical Storm Fay should move into the region for Friday and the weekend. The tricky part will be what impact(s) Fay will have on the area, if any. As of press time Fay’s pressure had dropped to 993mb per the latest hurricane hunter vortex message with outbound flight winds near 60kts (about 65mph winds). Based on this information I would expect Fay to strengthen prior to the center making landfall again later tonight or tomorrow.

The National Hurricane Center’s forecast track will bring this system slowly west-northwestward through the Florida Panhandle into the interior and perhaps coastal portions of Alabama and Mississippi. Since Fay’s outflow looks impressive I wouldn’t be surprised if this system nears hurricane strength later tonight. Even though Fay shouldn’t be a major issue in the Gulf, I would still expect a Fay’s wind-field to expand with northerly winds to develop across Acadiana beginning as early as late Friday with a nice northerly breeze possible this weekend. While still a tough call, it looks like drier air will move into Acadiana on the western flank of Fay allowing for highs to reach the mid-90s while rain chances decrease to 20% or less through the weekend. One caveat when dealing with the western side of tropical systems: while mostly dry at the distance we should be from the system, an enhanced tropical rain band will be possible in Acadiana this weekend but the risk of precipitation should be 20% or less at this point.

The upper Texas trough continues to dominate our pattern with a very moist conduit of air to stay with us at least through tomorrow. This trough is expected to weaken and perhaps drift back to the west while high pressure builds from the Great Lakes southeastward toward the Mid-Atlantic States. These features should dominate the future path of Tropical Storm Fay. As I alluded to in yesterday’s blog entry, Fay is expected to slow to a nearly stationary position late tomorrow into Thursday. The current National Hurricane Center forecast brings Fay back into the Atlantic tomorrow and allows for modest strengthening to a hurricane, then turns the system to the west-northwest into northeast Florida or southeast Georgia then toward Southern Alabama in 3-4 days. The 12z and 18z GFS models continue to show a more westward and more southerly track than the official NHC track which is in the center of tropical-specific models. But remember the GFS is a larger scale model and not tuned for tropical activity…however, as I indicated yesterday, the global models can’t be ignored when they remain consistent from run to run. The bottom line at this point: don’t be surprised by future NHC tracks if they are more to the left and south of the current track. The good news for most of us is even if this system moves significantly westward and possibly strengthens over the extreme northeastern Gulf it will likely not affect Acadiana but could actually drag down some drier weather on its western flank. Fay shouldn’t pose a direct threat to Acadiana or the offshore industry at this time. If Fay would turn sooner than later then we may have to reassess for the oil patch off the southeastern part of the state. Fay will likely batter much of the “Sunshine State” with heavy rains and it looks like the Florida Panhandle will have its turn. Hopefully some of the drought stricken areas of the Southeast U.S. will get beneficial rains as well. Weather-wise in the near term in Acadiana expect a good chance of scattered showers and storms tomorrow with coverage expected to decrease as we head toward the latter part of the week into the weekend.

A healthy chance of showers and storms will stay in the forecast for Acadiana over the next several days as a persistent upper low in Texas doesn’t go anywhere through Wednesday. Rain chances should stay near 60% or better during the day with activity quieting down nicely at night. Like the past few days, expect a few very heavy storms with the slight possibility of spotting a few funnel clouds with a few rapidly developing cells. The forecast gets rather complicated later in the week as the upper low begins to shear out while high pressure ridging develops to the north and along the East Coast. This should allow for more “normal” rain chances locally and will ultimately guide Tropical Storm Fay once the system gets to northern Florida.

Fay is still over open water this evening in the vicinity of Key West and could strengthen to hurricane status before completely making landfall across southern/southwest Florida. The National Hurricane Center officially brings Fay northward across the entire state with the system slowing beyond 72 hours. This is where it will get tricky as the global models including the 12z and 18z GFS model grinds the system to a halt in northern Florida or just of its northeast coast with a westward jog back through northeastern Gulf States possible later this week into the weekend. Now these models are not tuned for hurricanes/tropical storms but consistent model runs can’t be completely ignored and must be considered for large scale patterns surrounding Fay. It is not out of the realm of possibility that this system could get back into the extreme northeastern Gulf of Mexico and produce some rough conditions for the rest of the Florida Panhandle through Alabama and perhaps Mississippi this weekend. Anyway you look at it Florida will have plenty of liquid sunshine and some beneficial rains, but as always there will likely be flooding problems on many areas with some minor wind damage issues especially on the southern part of the state through Tuesday. Hopefully these rains reach the drought-parched areas of the Southeast U.S. Elsewhere in the tropics, an area of disturbed weather in the far-eastern tropical Atlantic shows some promise to be the next named system later this week or this weekend…the next name will be Gustav. This feature will take about 8-12 days before it could become a trouble-maker.

We had numerous spottings of funnel clouds with the storms that rolled through Sunday. It is not all the uncommon that we have these tropical funnel clouds to develop with the seabreeze showers in the summer. The atmosphere is very moist and unstable. These tropical funnel clouds form when the rain cooled air acts as a mini cold front, rushing out ahead of the storms and causes the air to rotate and form a funnel. Most of the time these funnels don’t touch the ground and if they do the only cause minor damage. From the pictures it looks like the funnel did touch the ground making it a weak tornado but we didn’t have any damage reported. Mire was the first area to spot a funnel cloud and later residents of Iota and Egan called with funnel cloud reports. It is likely that we could have more tropical funnel clouds over the next few days because the atmosphere will have the same setup.

 Through the next few days a stalled front will enhance our rain chances along with a few upper level distrubances. These cold pockets of air aloft make the storms that do develop grow taller and produce heavier rain and storms. These may be the conditions we need to keep us out of a drought and temperatures in check.

 Now to Fay. This storm is still set to make landfall in Florida on about Tuesday as possibly a category 2 hurricane. Right now it’s a tropical storm but will strengthen as it moves over the warm Gulf water. Upper level winds are pretty favorable for it to continue to strenghten but there has been some dry air moving into the western side of the storm. The front over us and high pressure in the western Gulf will make this storm make a northerly turn. So things are looking good for us but almost the entire state of Florida will be dealing with the impacts of Fay.

As we have been advertising over the last few days, we will see active showers and thunderstorms this weekend. A series of disturbances rolling out of the Rockies through Texas and eastward along the Gulf Coast will yield better than normal coverage of scattered showers and thunderstorms. As always, there will be areas that see a good soaking, some isolated spots of a few inches of rain, and other areas may see just some nuisance drizzle or spotty rains. There won’t be much rhyme nor reason to our activity, other than best opportunity for getting wet will be from mid-morning through the afternoon with activity slow to decrease during the evening and quieting down at night. The models agree for Saturday but are split on Sunday with the larger scale global models trying to dry us out while our in-house and online model (KATC Futurecast) keeping us wet. We’ll stay with Futurecast until both camps can agree. Next week should bring typical summer-weather but obviously we’ll be watching Tropical Storm Fay.  See below…

The National Hurricane Center upgraded Fay to tropical storm status based on Hurricane Hunter Data even though the center of circulation was over land in the Dominican Republic. The forecast track and especially the intensity will be tricky depending on how the storm interacts with land and the mountainous areas of Hispaniola and Cuba. The track models bring this system through Cuba over the weekend and turn it northwestward and then northward through the Florida Keyes and then northward along the west coast of the Florida Peninsula. Although the forecast track may change over the weekend, it appears that ultimately the aforementioned disturbances and associated upper low to our northwest will help to guide Fay’s path away from us…but as always that could change but we’re not expecting that to happen at this point. Current NHC forecasts will keep Fay as a tropical storm but when the system emerges over the very warm waters between Cuba and Florida they expect moderate strengthening to a 70mph tropical storm. We have seen explosive development with past hurricanes and tropical storms in this area in the past (Rita in 2005 and Charlie in 2004 come to mind) so don’t be surprised if South Florida may find itself dealing with a much bigger problem early next week. As we also say…stay tuned for the latest throughout the weekend. What to watch for this weekend: if the center of circulation is over water and away from land expect strengthening with a more formidable hurricane quite possible; if over land for a good period of time not much strengthening until the system gets over open water and away from land.

Drier air continues to filter into the region this evening as last night’s front has worked its way to the coast. It appears that we will see a one day respite from the humidity and shower and thunderstorm activity as the moisture should return back from the Gulf tomorrow evening. Temperatures will be pleasant in the morning with lows near 70 while it still will be quite hot Thursday with highs reaching the low-mid 90s. At least the relative humidity should stay in check. Unfortunately the humidity will return tomorrow night and Friday with sea breeze-oriented showers and a few storms returning for Friday afternoon. Another “strange for the season” upper low will rebuild over Texas this weekend allowing for a good chance of showers and storms Saturday, Sunday and into early next week.

It appears that a significant change may be underway in the tropics as the Madden-Julian Oscillation (MJO) Pattern is showing signs of reversing. This is a global circulation that while not fully understood is an important player in tropical and monsoonal activity worldwide. In the last week it appears that this change in pattern will lessen the westerly shear factor in the tropical Atlantic which in turn will likely make it more favorable for tropical development. I received a number of emails about the long-range 12z GFS model which puts a significant tropical system in the Gulf of Mexico in the last week of August. The model is apparently acknowledging the lower shear environment that we are talking about, but the  potential system has yet to fully emerge off of the African Coast…and it’s just one computer model run. Inspecting the 18z model yields a different solution, but still indicates a tropical system running through the Caribbean roughly the same time, about 8-11 days down the road. At this point, I wouldn’t get too concerned about what is possible over the next week or two, but rather be ready for a busy tropical period from late August through the first week of October. There will likely be some major storms Atlantic over the next 6-8 weeks with the Caribbean particularly vulnerable per Drs. Klotzbach and Gray.

In the near term, the National Hurricane Center cancelled recon of the disturbance that is northeast of the Caribbean but they plan to fly a research mission later tonight. Nonetheless this system has potential to develop and be a threat to the Bahamas and SE U.S. this weekend into early next week. Initially models were consistent on bringing any potential system toward the Gulf, but the trend has been for a northward turn around the Bahamas. But as always, things will likely change with near-term and long term projections. Another disturbance west-southwest of the Cape Verde Islands may also develop down the road but this one looks far enough to the north to stay and Atlantic system. Elsewhere some active disorganized storms were embedded in the ITCZ in the mid-deep tropical Atlantic while another healthy wave is coming off of the African coast.

A good chance of showers and storms remains in the forecast overnight as a low pressure system in the northern part of the state drifts eastward. The heaviest weather today has been from central Louisiana on northward and eastward into Mississippi where a Tornado Watch continues late this afternoon. Showers and locally heavy storms will be possible overnight through the morning hours with drier, almost slightly cooler air moving in for tomorrow evening. Activity should stay below severe levels but isolated very healthy storm are a good bet. As always this time of year the front will become stationary along or just south of our coast so rain chances should go down but the risk of lingering isolated afternoon coastal storms will be possible Thursday and Friday. But most of us should be dry for those days with relatively comfortable humidity possible for Thursday. The return flow from the Gulf will likely commence Friday with scattered, mainly afternoon showers and storms possible this weekend. Daytime highs will stay in the low-mid 90s through early next week…and then things could get interesting…

An area of disturbed weather east of the Windward Islands was investigated by Hurricane Hunters this afternoon, while the National Hurricane Center chose not to upgrade this system based on the data this afternoon but there is a fairly high probability that this system will develop over the next few days. The long-range and tropical models show not only the possibility of a significant tropical system developing by late this weekend, the long-range mean flow would bring this system into the Gulf posing some sort of threat to Louisiana. A lot can change over the next few days, and this system is in a formative stage, however it would not be unreasonable to think that there could be a significant a hurricane threat in the Gulf for Tuesday through Thursday of next week. Stay tuned for this one…

The radar got a rest today after a busy day Friday. Drier air shut off our rain chances but moisture will make a quick return to start the work-week and we can expect scattered afternoon showers and storms. A front moving across the southern plains will help to produce more widespread rain by Tuesday but it looks like the heaviest downpours will be to our north. We do need the rain especially in the central parts of the state and we’ll take any rain we can get. In the tropics it’s been quiet with any waves that develop fizzling out very quickly.

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Drs. Klotzbach and Gray issued their August update for the rest of the hurricane season for the Atlantic Basin. Consistent with their earlier forecasts and the one issued by NOAA earlier this year, it is expected to be quite active in the Atlantic Basin. Key indicators this year are warmer than normal sea surface temperatures, below normal surface pressures in the Atlantic and Caribbean Basins, below normal African dust storm activity, and lower upper atmospheric shear. Thus the forecast group from Colorado State have increased their forecast to a total of 17 tropical storms (10 is average), 9 hurricanes (6 are normal) and 5 major storms (category 3 or higher, normal is 2). Five tropical storms have already formed in the Basin this year, two of which have become hurricanes, with Bertha the only major storm this year. Therefore, that leaves 12 more storms, 7 hurricanes, and 4 major storms still left on the “theoretical” table. The most important thing to remember is that whether it is a busy season or not, or whether the forecast is for a busy season or not, we all need to be equally prepared for every season as it just takes one storm in our area, to make it a “locally very busy” season. If you read the paper and examine the probability of landfall products, you will find that the risk of a major hurricane from the Florida Panhandle to Texas will be near 42% with the average near 30%. The forecast for the Gulf has been near 40% over the last 4 years; 2004 brought Ivan and 2005 brought Dennis, Katrina, and Rita. Over the past two years there have been no major strikes in the same zone. So there is obvious season to season variability in tracks and intensity that are impossible to forecast accurately. But the statistical scheme employed at least gives us an idea on whether the risk is greater or less than normal…but there is no “true” normal…just data averaged over the years. I broke down the parish by parish risk for Acadiana just to give us all an idea of what we can expect. Interestingly enough, the year to year “normal” risk of seeing hurricane force gusts (greater than 74mph) is about 9.8% from Lafayette Parish on south and eastward, while it is 6.6% or less to the north and west, and likely even less for the northern most parishes of Acadiana. Based on this year’s forecast, the risk of hurricane force gusts is closer to 14.6% (9.9% to the west). The risk of wind gusts exceeding 115mph in Lafayette Parish year to year is near 3.3%, but this year the forecast is at 5.1%. Obviously these are low end numbers and risks, but it does tell us that once every 10 years any given parish in Acadiana will see hurricane force gusts. And about once every 20-30 years any parish can see gusts exceeding 115mph. Every year the odds are against a major damaging storm, but the law of averages eventually catches up with us…hopefully it won’t be any time soon, but the statistics continue to say “be prepared” no matter what the seasonal forecasts bring, and whether global climate change has any effect…and that will be another blog entry for sure!