KATC StormTeam 3 Weather BLOG

Our nice and dry weather will last another couple of days with highs continuing near 90 while lows at night will be in the upper 60s.  Humidity will begin to return Sunday so it will feel more uncomfortable for Sunday afternoon.  A series of upper disturbances emanating from the northwest combined with another weak frontal boundary may produce a few scattered showers late Sunday but activity will be mostly likely Monday into Tuesday. 

Things are looking up in the Weather Lab as drier air and one of the first real changes in our air mass in months is on the way.  A few isolated showers will be possible overnight tonight through first thing tomorrow morning, but drier air advecting into the region will scour out the moisture and the clouds by late tomorrow afternoon.  Tomorrow will be another warm one with highs reaching the lower 90s, but northerly breezes and lower dew points should make it feel markedly better.  The best push of dry air will come for Thursday and Friday with lows dropping into the upper 60s while daytime highs get suppressed into the upper 80s to near 90.  Our quiet and almost comfortable weather should last through Saturday with humidity returning for Sunday with a few showers possible early next week. 

What a difference a weekend makes…Tropical Storm Ernesto got shuttled through Haiti and the Dominican Republic and is just emerging off the Cuban coast as a ragged system.  Upper level shear took its toll on the storm and helped the system take a much more northern course as compared with the projections 48-72 hours ago.  This storm is another reminder that the 3-5 day forecast path is subject to large errors, and just because the cone is pointing toward you doesn’t necessarily mean the storm is coming your way.  Last Friday night on the 10pm show I indicated that the models had split with forecast tracks either toward Florida or toward the Texas/Mexico coasts.  I also pointed out that although the 10pm track was pointed straight at us, it was the best average based on the models…and sure enough it did change. 

Although we do not anticipate this to be a major storm now it could be potentially be a major mess for Florida and up along the East Coast…at least it is not our problem!  

The same upper trough that will eventually steer this system northward will bring us drier more pleasant weather after tomorrow…so get ready for it to almost feel like fall…sorry it will still be near 90 during the afternoon, but at night look for some upper 60s for later this week!   

Program Note: Please tune in to our 1 hour special on Katrina tonight…on my end I will be explaining why the storm became such a monster. 

Rob Perillo

Tropical moisture continues to envelope the region with locally heavy showers and storms likely this weekend.  Rain chances should be highest tomorrow and about 10-20% lower on Sunday.  Our pattern should get back to “normal” early next week with scattered afternoon storms and more heat. 

Next week may be however anything but normal provided Tropical Storm Ernesto follows the current projected path.  Right now Ernesto’s low level circulation is exposed with all the convection well east of the center.  This means wind shear is keeping the storm at bay.  Unfortunately the shear will begin to decrease after 24 hours…and if the storm stays south of the islands (except Jamaica) there will be ample opportunity for strengthening.  Even if Ernesto makes to the Gulf as a tropical storm, Gulf water temperatures in the upper 80s combined with a low shear environment will all spell the possibility of a major storm.  As for the track, we are too far out to determine what the upper air pattern will be along the northern Gulf rim next week.  Computer models are split in two camps: 1) a weakness in the ridge allows for a turn to the north or 2) the ridge builds over the region and pushes the storm more westward.  The third scenario is that the system slows or stalls in the Gulf.  If it’s a big storm, I don’t think that would happen.  So if we average the possible tracks you get something that looks like what the Hydrological Prediction Center is extrapolating…putting us in the thick of things for Thursday/Friday of next week.  As we said yesterday we have plenty of time to watch this system and we can all cheer for more shear, but if this system makes hurricane status by the end of the weekend and stays on track, I would be starting to think about my hurricane plan. 

Rob Perillo

As expected we saw heavy downpours today and expect more of the same tomorrow.  In fact, rain chances are forecast to stay above normal into early next week.  There has been little change from our previous thinking on this wet pattern that we have become immersed in.  So keep the umbrella handy and expect more localized street flooding in heavier storms tomorrow. 

So what’s the skinny on TD #5?  Hurricane hunters appeared to work overtime to close off a circulation with this system so it could be officially upgraded.  TD 5 on satellite imagery looks good enough to be a depression or tropical storm, but dry air on the western side of the system combined with upper level westerly shear will make it rough for this system to develop in the near term.  An upper low to the west of the system should continue to inhibit development by providing shear and dry air, however, if this system survives the next 48 hours it will have ample opportunity to strengthen in the NW Caribbean and ultimately the Gulf of Mexico.  The rest of the road shows above normal water temperatures all the way to the Gulf so there is ample fuel available.  The key will be if TD 5 can encircle itself with a more favorable environment to build on the process of converting atmospheric and oceanic heat, while shutting out the drier stable air to its north and west.  The official NHC forecast makes this system a tropical storm tomorrow and keeps it a tropical storm through 5 days due to considerations of island interactions and negative influences…but as we all know the intensity forecast will likely change, one way or the other, it always does.  It is way too early to tell where this system will ultimately make landfall, but it is conceivable that this system could threaten anywhere in the Gulf, but I would favor the Northwestern Gulf…that means Texas and Louisiana could be in the mix.  But predicting what our upper air pattern will look like a week from now is quite tricky.  If this system were to threaten our area it would be sometime late next week.  A lot has to happen between now and five days from now when the system could enter the Gulf, so don’t let tropical anxiety get to you yet. 

Rob Perillo

A good chance of storms will stay in the forecast as abundant tropical moisture looms across the region.  Daytime heating along with impulses from a nearly stationary front draped over the northeastern part of the state and the lack of high pressure ridging will all conspire to keep our chance of getting wet well above normal through the weekend…and maybe into next week. 

Next week should be an interesting one provided the disturbance east of the Windward Islands gets more organized.  Today the disturbance appeared to be getting more concentrated on the southern part of the tropical wave that it has been following.  The northern part of the wave however, has had a fair bit of dry air and Saharan dust intruding which has been a mitigating factor for development of most waves this season.  Development with this system will become likely if it can separate itself from the dust.  Unfortunately, the tropical models I looked at today develop this system aggressively (but the models have a lot of climatology (not as much current meteorology) built in), but there is the distinct possibility for development into something more than a category 1 storm prior to threatening the Gulf.   To boot, high pressure may not be strong enough next week to protect us from Gulf intruders so as we said yesterday, we’ll be keeping a very close eye on this potential system.  Incidentally, the next named system will be “Ernesto”.  Elsewhere, Tropical Storms Debby in the far Eastern Atlantic is likely to recurve in the open Atlantic. 

Rob Perillo

Elevated rain chances will be the mainstay in the forecast through the rest of the week and into the weekend…perhaps into a good part of next week as well.  Basically, the ridging aloft has weakened opening the door for daytime heating induced showers and storms.  In addition, the atmospheric precipitable water has increased substantially lending to very heavy downpours with the storms.  Winds aloft are quite light lending to very slow storm movement; this will lead to the possibility of localized street flooding in some of the storms.  The Gulf will add to the equation funneling more thunderstorm fuel in the form of tropical moisture through the weekend and into next week. 

The Gulf should also be wide open for tropical waves/disturbances into next week with the models beginning to bird-dog a system that will approach the Gulf next week.  The models are grabbing onto a tropical wave that is roughly 800-900 miles east of the Windward Islands…so this system bears watching.  Extrapolating the model data brings this impulse to our doorstep by late next week.  Elsewhere, TD#4 is looking a little better on satellite imagery late this afternoon so tropical storm status may be possible by late tonight or tomorrow.  This depression should stay an Atlantic system as it moves NW and eventually NNE, or it will shear apart if it tries to take a more westerly course.  

Rob Perillo

Our rain chances will go above normal over the next several days as high pressure retreats back to the west.  In addition, deeper tropical moisture will begin to build into the region.  Most storms will be produced by daytime heating most days, while a few upper disturbances may roll in from the north and east, further enhancing our rain chances.  This pattern will likely persist into the weekend…perhaps beyond. 

Meanwhile, in the tropics there is plenty of tropical moisture pooling in the western Caribbean with a surge of this moisture expected to push into the Gulf.  This moisture could add more fuel for scattered showers and storms later this week and into the weekend.  Much farther to the east Tropical Depression #4 formed south of the Cape Verde Islands.  Current indications are that this system will become a tropical storm (Debby) and will continue to move to the west-northwest.  Too early to tell whether this system will be a player in our part of the hemisphere, but first blush would keep this as an Atlantic system.   

Rob Perillo

The upper low in the west-central Gulf will continue to head westward toward the Texas and Mexico coastlines tomorrow with scattered storms the result over Acadiana.  Coverage of the storms should be a little better than today, but drier more stable air should move in for Sunday thus lowering the rain probabilities. Another upper and surface disturbance should again enhance our rain chances beginning late Monday and continuing into Tuesday.  Typical summer weather will follow mid-late next week with a possible surge of tropical moisture returning to the region for late next weekend.  Daytime highs will continue on the low-mid 90s this weekend and much of next week. 

The tropics remain very quiet, but the computer models continue to advertise that it will change.  A disturbance that has emanated off of the African coast has plenty of potential to develop, but we have 10-14 days to watch it before we’ll have to worry about it, if at all.  The models have also been flagging that something will develop in the SW Caribbean and surge toward the southern Gulf late next week, but as of this writing I can’t seem to identify what the models are grabbing on to.  Sometimes in this area the models get fooled by future Pacific systems as they can’t decipher what ocean the tropical surge will develop in.  Bottom line: be ready for us to be talking about something by late next week.  Program note: “Lessons from the Gulf” KATC’s Hurricane Special will air again Saturday evening at 5:00pm.  Have a good weekend. 

Rob Perillo

The big heat yielded to big thunderstorms this afternoon as the upper low in the Northeast Gulf helped destabilize the atmosphere.  The result was some intense thunderstorm activity this afternoon and evening that produced better than 7,000 cloud to ground lightning strikes per hour for several hours.  We had sporadic reports of damaging winds and hail.  Winds gusted to 40-60mph in the heavier storms while mostly pea to marble size hail fell in more moderate storms.  I did get a couple of reports of quarter size hail in Rapides Parish. 

The forecast over the next several days will call for more scattered showers and storms, but the strength of the storms should be less than those of today for tomorrow, with more garden variety splash and dash showers and storms Friday and Saturday.  It won’t be as hot, but it will still be hot with highs in the mid-90s tomorrow and low-mid-90s on Friday.  Our heat wave should resume into next week with decreased rain chances beginning Sunday.   Highs should be back into the mid-upper 90s starting Sunday and continue until at least Wednesday.  Low and behold a weak frontal boundary may get close to us toward the end of next week so maybe a break in the humidity is in the offing.  Although tropical activity will begin to ramp upward in the next week or two, at least we can look forward to the slim possibility of cool fronts getting closer to us as we head toward September! 

Rob Perillo