KATC StormTeam 3 Weather BLOG

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…

Bonnie was downgraded to a tropical depression late Friday afternoon after spending about 12 hours over land in southern Florida. 

Bonnie is moving smartly to the west-northwest but should slow somewhat along with a gradual turn to the northwest Saturday.  This may provide some opportunity for the system to strengthen back to tropical storm status. 

Conversely, some of the latest tropical models weaken the system back to a tropical wave prior to landfall Saturday night/Sunday morning over eastern-most Louisiana or southern Mississippi. 

It appears that the main tropical threats from Bonnie will be confined east of Acadaina but there may be the threat of heavy tropical showers and storms spreading westward into the area mainly Sunday…so that is what we will be on the look out for.  Storm surge issues and damaging winds are not expected for the Acadiana area. 

The remnant moisture from Bonnie may linger Monday and Tuesday across the area keeping the chance of some flooding with us until drier weather moves back into the area mid-late next week.  Stay with KATC online or on the air for the latest this weekend…

If you think it’s been rather hot over the last couple of months you are right!  June temperature data analyzed for Lafayette has revealed yet another record hot month.  Mean temperatures (average of highs and lows) of 84.6 degrees was the hottest on record.  Temperature records in Lafayette date back to 1893.  This record heat comes on the heals of the hottest May on record.

Temperatures have averaged more than 4 degrees above normal over the last couple of months with the main culprit being steamy overnight/morning lows that have averaged nearly 5-6 degrees above normal.  This can partially be attributed to above normal Gulf and Atlantic sea surface temperatures and seasonal variability of a drier than normal spring that has spilled into the summer months.

The bottom line for most of us in Acadiana is that our cooling/electric bills will be higher than normal for June.   July temperatures have been running closer to normal thanks in part to more shower and thunderstorm activity through the third week of the month.

The tropical moisture plume will re-establish across Southern Louisiana this week as two areas of weak low pressure will be players in Acadiana’s weather.  The front burner system is a weak (1010mb) low just south of Atchafalaya Bay which is expected to drift northwestward through Wednesday.  Although this system is not truly tropical in nature nor is it expected to strengthen much, it will be responsible for enhancing Acadiana’s rain chances (daytime and night-time) for Tuesday and Wednesday.

Locally heavy rainfall will be possible as this system will open the door to deep tropical moisture through mid-week. 

A secondary system in the Northwestern Caribbean is associated with a broad area of surface low pressure with deep disorganized tropical showers and storms.  This feature will push in the central Gulf of Mexico by mid-week and should help to provide another day of enhanced showers and storms for Acadiana Thursday. 

The bottom line is that this week will be another wetter and cloudier than normal one…at least this will keep our high temperatures closer to the mid-upper 80s.  Few storms and hotter temperatures should return for the weekend.

Flood Watches are in effect for much of Southern Louisiana through Thursday morning including the I-10 and coastal parishes in Acadiana.  Rainfall totals over the next several days will generally be in the 2-3″ range with isolated areas possibly receiving 5″ or more through Thursday. 

KATC’s FutureCast is actually indicating much more rainfall over the next 72 hours across portions of Louisiana with hot spots over Southeast Louisiana and possibly coastal Acadiana exceeding 10″.  What happens in “real-life” and on the computer are almost always two different things but the model is highlighting the potential for heavy rains….hopefully most of this will remain offshore.

Meanwhile Alex continues to churn and slowly intensify in the Southwestern Gulf of Mexico with landfall expected south of the Texas border Wednesday evening/night.  Alex should become a hurricane later tonight as drier more stable air on the northwestern flank of this system has kept the system a tropical storm today.  That drier air appeared to be getting sealed out of the system late this afternoon so the storm is likely very close to a hurricane as of this evening.

Gusty easterly winds offshore the Louisiana coast will likely ramp up Wednesday while swells from the south make for 4-8 foot seas close to home but deep water areas toward the oil spill will likely push into the 8-12 foot range.   Tides along the coast were running 1 foot above normal today and should continue to near 2 feet above normal Wednesday.  A Coastal Flood Advisory continues as of this evening for elevated tides expected through Thursday.

As expected, the U.S. Drought Monitor upgraded all of Acadiana’s status to a “Moderate Drought”.  Rainfall deficits have been running about 8-12 inches below normal this year with most areas receiving less than one half of an inch over the last 6-8 weeks.

Fortunately rain chances will increase this weekend but activity will be mostly scattered in nature but there could be a few spots that could get some relief.  Sunday into Monday may be a little more interesting as the atmosphere may become more conducive to meso-convective complex development.  These are larger scale thunderstorm clusters that can generally get a much larger area wetter.  Upper level winds will be on the rather light side combined with a healthy plume of deeper tropical moisture some areas may actually get some relief from the drought.   Check with our FutureCast Models and Power Doppler 3000 for the very latest throughout the weekend

Rain chances should decrease somewhat into next week, but it appears that Acadiana’s overly dry pattern should change favoring at least some slight rain chances and the prospects for more meso-convective complexes as we finish off the last couple of weeks in the month.

The latest pictures today courtesy of NASA’s MODIS website clearly show the oil spill and some of the containment that is occuring at this time.  Unfortunately winds and seas will stay elevated through the entire weekend making operations offshore that much more difficult.  In addition based on NOAA’s latest assessment the slick and crude will encroach upon coastal Plaquemines Parish tonight.  Based on a continuation of surface winds and coastal tides I have put together a threat zone through Monday based on the ongoing forecast. 

I am not however an expert oceanographer nor are these official NOAA projections (as the forecasts officially are only for 24 hours out), but based on current surface winds and currents in the Gulf of Mexico it appears that some oil may travel as far west as Grand Isle by Monday.  

I would not be surprised to see this slick affect the entire Louisiana coastline through the next week to 10 days unless the slick is miraculously contained much sooner than the 2-3 week minimum projection at this point. 

To make matters worse with the gusty south-southeast winds tides will increase to 1-2ft above projected normal lunar tides raising water levels as high as 3ft above normal mean low water.  This would allow the contaminated water to drive deeper into Louisiana’s coastal marshes.   In addition, scattered shower and thunderstorm activity will become more likely at the accident site Friday through Monday…hopefully the fresh water run-off from the storms will help the marsh but it will likely hamper containment activities.  Stay with KATC for additional updates.  Rob 

After looking for a high resolution visible satellite picture from the NASA MODIS website I found that you can clearly see not only the smoke from the grass fires in Vernon Parish this afternoon but if you zoom in closely on the High Resolution Link (warning this is a large file) you will be able to see the oil slick offshore from the platform that exploded last week migrating southeastward in the Central and Southern Gulf of Mexico.  The Louisiana Coast has been fortunate not to be contaminated with this slick as brisk west to northwest winds have dominated across the area since Saturday.  Normal currents in the Gulf migrate westward across the Northern Gulf of Mexico but the predominate winds have been over-riding the natural current forces.  Later this week however, southeasterly winds will return to Acadiana and Louisiana opening the window of opportunity for the slick to migrate toward the Louisiana Coastline.  The slick appears to span much greater than 30 miles as reported earlier today.  This image comes from a NASA polar orbiting satellite which circles the Earth several times a day at roughly 120-150 miles above the earth which allows for much higher resolution images (but fewer pictures) as compared with typical geostationary orbiters that are parked 22,000 miles above the planet.

As for the fires in Vernon Parish, they were initiated by by a burning railroad box car that was filled by wood.  This allowed for three distinct grass fires to ignite leaving a smoke plume to fan southeastward with the prevailing northwest winds Monday afternoon and evening.  The fires were reported under control as of late Monday afternoon

Be sure to check with KATC’s Wind Forecast Maps regularly for the latest on prevailing winds.

With less than 2 months before the official beginning of the Atlantic hurricane season, Colorado State hurricane forecasters Drs. Klotzbach and Gray issued their April 2010 Hurricane Forecast today and it appears to be much busier than last year due to an expected weakening of El Nino and above average sea surface temperatures in the tropical Atlantic.  Their forecast is a resumption of the 20-25 period of enhanced/increased tropical activity as compared with the long-term average.  The group continues to indicate that we remain in a several decade active pattern that started in the mid-1990s. 

The forecast for this year calls for 15 tropical storms (the long term average is 10), 8 hurricanes (the long term average is 6), and 4 major, Category 3 or greater, storms (long term average is 2).  Much of the forecast hinges on whether El Nino will fade for the prime-time part of the season which is August through October.  

“We expect current moderate El Niño conditions to transition to neutral conditions by this year’s hurricane season. The predicted weakening of El Niño conditions combined with a very strong anomalous warming of the tropical Atlantic are the primary reasons why we are increasing our forecast.” according to Dr. Klotzbach who has taken the reigns from Dr Gray in the seasonal hurricane forecasts issued by the group.

If the forecasters are right the risk of a severe, Category 3 or higher storm striking somewhere between the Florida Panhandle to Brownsville will increase from a long-term average of 30% to 44%.  These projections are similar to their forecasts that were issued for the very busy 2004, 2005 and 2008 hurricane seasons.   

Although it remains impossible to pinpoint where the storms are going to strike, based on the data revealed in the report, expect a very active tropical pattern for the latter part of August through the first week of October.