Isaac likely will affect U.S. next week, but track, strength very much in question
Tropical Storm Isaac, as of this hour, is not that impressive. Its central circulation has become disorganized and it’s clinging to 45 mph winds, 6 mph above the baseline for tropical storm status. But it’s also not even in the Caribbean, yet, with lots of warm ocean water and a fairly conducive upper air environment ahead of it to grow and strengthen. Largely because of the Republican National Convention being scheduled for Tampa next week (Aug. 27-30),and the fact that that there hasn’t been a Category 3 or stronger hurricane landfall on a U.S. coastline since 2005 (covered in Weather Journal and a USA Today front-page article today) there is going to be a lot of attention — even a little more than usual — on Isaac’s track and strength over the next several days. At this stage, here is what is known: (1) Isaac likely WILL affect the U.S. coast in some form next week and (2) it is not at all certain that it will be a major hurricane (Category 3 or stronger, 111 mph or higher winds) at U.S. landfall, if there is one. Between its current location and the U.S. coast are several land masses that could weaken the storm, particularly the 8,000-10,000-foot “hurricane killer” mountains of Hispaniola. Isaac’s track depends largely on what happens with high pressure to the north of it — the same high pressure that will be bringing us several days of similar weather, with highs near normal (80s highs, 60s lows) and scattered afternoon showers and storms. Since we’re close to football season, think of a running back looking for a hole in the defense to slip through. Isaac will follow whatever weakness develops in high pressure to the north. Detecting when and where such a weakness occurs is a major reason forecast models vary all the way from the Savannah, Ga., to New Orleans with the projected U.S. landfall of Isaac. 
(Inset map shows the 12Z European model’s depiction of Isaac on Thursday morning, approaching the Louisiana/Mississippi Gulf Coast. The “L” and “H” in this case are not about atmospheric pressure, but about winds speeds at about a mile up, with L marking the calm spot of the eye and H marking a 114-knot or 131 mph burst in the eastern eye wall.) As we move forward in time, the forecast models should come into at least somewhat better agreement on Isaac’s track by moving closer on the position and strength of high pressure to the north. Remember that on the tropical atmospheric playground, it’s not big bad hurricanes that are the bullies that push everything around, it’s the bulky, stagnant high-pressure systems.
Southwest Virginia will be affected by Isaac, either directly or indirectly. Direct impacts could occur if the system moves northward from the Gulf or its moisture becomes swept north or northeastward by a frontal system moving southeastward. Flooding rains, gusty winds and tornadoes are possible with inland-moving tropical systems, depending on many factors. Indirect effects, especially with a more westward path, could simply mean more of a southeast wind flow and a tendency to pump up high pressure to the northeast of it. If the latter is the case, Isaac may assist in summerlike heat (mid 80s-low 90s highs) and humidity re-establishing itself next week.
Before it ever becomes an issue for the U.S. mainland, Isaac has the potential to be very troublesome for Puerto Rico, the Dominican Republic, Haiti and Cuba, to name only a few Caribbean nations. It’s still 5-7 days away from the U.S., and the average forecast track miss on hurricanes that far out is about 500 miles.
As if Isaac weren’t enough, we’ll probably soon have Tropcial Storm Joyce following on its heels.
August 22, 2012 - 5:05 PM
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If I had to make an absolute prediction on Isaac hitting the U.S. right now, I would go for Category 2 hit on Appalachicola in the Florida Panhandle. A barely educated guess is all that would be. May be some tendency for a trough/cold front entering the Ohio/Tennessee Valley to nudge it north at some point, east of where the Euro wants to go with it but considerably west of most of the current GFS/hurricane model guidance. Bad news with that track would be that it would be over the open Gulf of Mexico for much longer, with some extremely warm ocean temperatures, and could gain greater strength than if it hopskotches from Hispaniola to Cuba to Florida quickly.
Sea surface temperatures in the Gulf of Mexico. Anything yellow is 30C or 86F. Spots of red are 32C or close to 90. Coolest I see is around 27C, which is 81F, more than sufficient to support tropical cyclone.
http://www.ospo.noaa.gov/data/sst/contour/gulfmex.cf.gif
The gas is in the tank, for sure.
KM – great call on the Blacksburg low temp (51 yesterday). You indeed called it about 10 days ago!
Quagmire- really appreciate your enthusiasm about Isaac, but the comparison to Camille/Katrina makes me yearn for this winter and the inevitable comparisons to Jan. ’96 and March ’93 that will inevitably be made!
Yeah winter of 93, 96, and 09-10 kicked butt! I will order up another if the big man upstairs would allow! LOL
I got lucky, Mike. Got one day when the sky cleared and the winds calmed, even if the surface moisture was so thick it created dense fog. Would have liked to see how cold it could have gotten with dry air. There were more than 300 record lows set, mostly in the central U.S., Sunday through Tuesday.
Randy, was by your mounteen twice this week on the way to Callaway.
Mr. Brand you probably went by my house. I would have waved if I was at home and knew it was you
will have lots of more info in the morning. Good night all
Meanwhile brutal month of August continues. Only one day (Sat. the 18th) had a high in ROA below 90, and even that was 87. Three days have reached 100, and 8 more have reached at least 95. More of the daily lows have been in the 70s than the 60s. Only reached 91 today, and it was bearable.
“Where am I? Oh, Dr. Emmett Brown just took me on a ride in his DeLorean to Roanoke in August 2007, which even had the same lineup of dates and days of the week as August 2012.” Boy, am I ever grateful to be “BACK TO THE PRESENT.” Even if a destructive hurricane is a real possibility for some poor souls somewhere in the Caribbean and the coastal USA.
Thanks for all the links and stuff, KM and CGQ. I had no idea that the possibility exists for Isaac to become another big Gulf hurricane, until I saw the image you posted, KM. As Kevin said, the rocket fuel is sitting in the Gulf …. if Isaac becomes a very naughty boy, goes that way, and lasts until then.
I remember how Katrina was a fairly ordinary hurricane when it went through southern Florida (Category 1, I am fairly sure). Then I remember awakening early one day before work (Friday before it hit Miss. and New Orleans?) and suddenly it had exploded into a monster that filled nearly the entire Gulf. I remember staring at the display on the screen (or maybe it was the images on The Weather Channel) and being in shock. Had trouble believing what my eyes were seeing. I hope Isaac doesn’t come close to doing that.
Just watched the heavily criticized Jay Webb on My 19. He showed what the GFS is showing going way out in time. Landfall near or just north of Tampa, then sweeping N and then NNE and going up the East Coast (I guess either just inland or just off the coast) Heavy rainfall amounts for most of Virginia, with the biggest amounts well east of the Blue Ridge. Looked like possibly 2-3 inches for ROA, less for Bburg of course, more for Lynchburg and Danville (both of those cities could use the rainfall, but probably not all at once), and hardly anything for the counties that border WV. As the great Other John once posted here at least a couple of years ago, take all this “with a grain of salt the size of a Buick.”
Most model guidance is clicking farther west. Saw on Twitter that it appears the circulation center may be farther south than projected which would lead to a more westerly track. I’ll stick to my Appalachicola guess for now — fully realizing we’ll probably get soaked if that happens.
By the way, Kevin, congratulations. You had mentioned at least a week ago (I think) on this blog the (nearly) 7-year gap since the most recent major hurricane to strike the American coast. And today USAT had it as its front-page article. I liked what I read in the USAT article, by the way, which is something I cannot say about lots of their articles. How probably too many folks, especially young adults and teens, have gotten complacent, even though they live in (possibly) harm’s way along the Atlantic or Gulf Coast.
Every one of the comments here by folks who have witnessed a big hurricane first-hand (even if it was at an inland location) do NOT fall in that category. They know enough to GTF out of Dodge if they are on the coast and a Cat 3+ is headed at them. Too bad it is not true for the general population.
An interesting tweet from Dr. Rick Knabb, director of the National Hurricane Center:
“At any specific time next 5 days, #Isaac has highest chance of being tropical storm; major #hurricane unlikely”
http://ow.ly/daomh
Just an FYI while we are discussing the “tropical storms” – today is the one year anniversary of the earthquake in Mineral (Louisa), VA.
Extremely foggy up here on the ridge this morning.
I was driving and never felt that earthquake. I did feel one of the strong aftershocks in our final weeks of living in a third-floor apartment.
Isaac winds are down to 40 mph, barely tropical storm force, as it continues to struggle to get organized. Models have clustered a little more toward a track near or just west of the Florida peninsula. Appalacichola in the Florida Panhandle, my initial guess on US landfall, is near the center of the National Hurricane Center cone.
http://www.nhc.noaa.gov/graphics_at4.shtml?5-daynl#contents
The central to western part of that cone of uncertainty over the Gulf/Florida area would be a path favorable for heavy rainfall in our neck of the woods late next week.
Dave Tolleris is saying this morning that if the European model, which he favors, wins out, it will bring beneficial rain to the midwest. He really trashed the 06Z GFS.
It looks like we can forget about Joyce………unless you will be Vacationing in Bermuda next week.
The Euro has been consistently farther west than the other models. But even its latest run is farther east than it was — landfall near Pensacola, Fla. in the western Panhandle. Earlier it was bringing it ashore close to New Orleans (see inset map in blog post).
Quag’s Thursday AM Tropical Update for August 23:
Euro model still holding with slight shift to the east as GFS, Canadian & UKMET make significant shifts to the west coming in line with the Euro.
Issac still on track for becoming a HUGE Hurricane for the LA/MS/AL/FL Gulf Coast Region…
As Kevin eluded to above, the 0Z Euro has shifted a little to the east with landfall potential increasing for the Alabama Gulf Coast/Florida Panhandle say the Mobile/Pensacola/Fort Walton Beach area. However, I would still keep the Louisiana Gulf Coast region on my watch list anything can still happen.
A side note, the Alabama/Florida Panhandle area is my second home and 3 of my favorite beach bar/restaurants is in the cross hairs. One of those places is the world famous Florabama Lounge in Perdido Key, FL/AL. The bar sits on the state line. I love this place and it could very well be ground zero for Issac. Another one of my gulf hang outs is A.J.’s at Destin Harbor. But like all other canes before these 2 wonderful establishments have always rebuilt and came back to life better than ever. I sure could slurp down a dozen raw oysters and a beverage right now. yum!
Rather than waste more space, I’ll be back later with the links and report on the 12Z models which will be out soon….
Quags
Kirk is just now coming off Africa and will bear serious watching for the SE US. more shortly
Our weekend family reunion is Labor Day Weekend at the Chapel. Rest assured that Isaac will attend with or without an invitation.
I’m sure the Star Trek fans on here would have a field day with a hurricane named Kirk.
I know I would, Kevin…I’m a Trekkie.
As for hurricanes and evactuations, I’ve had no problem riding out Cat 1/2 storms, but once they hit Cat 3, I’m formulating the exit plan. Having grown up in Virginia Beach, the tidal storm surge would only be a problem where I lived for Cat 4 and above, but street flooding happened in severe thunderstorms if they dumped too much rain too quickly. Winds were more the concern though, given how rapidly many communities were built in the 80′s and 90′s, but any level of flooding would cut us off from emergency services and access to provisions after the storm.
In 1999, we rode out Dennis, Floyd, and Irene. We experienced flooding with all 3, the worst coming with Irene after the drenchings from the first 2. Our street was filled with several feet of water for well more than a day after the storm, with some streets remaining flooded for much longer. My home golf course, where I also worked at the time, was mostly flooded for the first couple days afterward, and the flood waters did not fully receed for 2 weeks. It was a mess.
Tropical Storm Joyce is official now … but, besides Bermuda, expected to be a fish storm.
http://www.nhc.noaa.gov/graphics_at5.shtml?5-daynl#contents
AccuHenry is out on a limb and predicting an EASTERN Florida or Savannah/ Charleston landfall. If I’m not mistaken, none of the models go over there. He says a weak storm will follow the ridging more. I thought a weaker storm was LESS influenced by outside factors compared to an actual hurricane. What gives?
…. just in time for the 12Z GFS to join the club on Isaac making landfall in the Florida Panhandle.
http://tinyurl.com/9vtwzvj
Matt: A very weak tropical system sometimes isn’t picked up by the upper-level flow much and kind of meanders. A very strong hurricane can sometimes warp the atmosphere on its own to kind of do its own thing. It’s the vast majority in the middle that are most affected by upper-level wind dyanmics, especially big high pressure systems.
Thank you GFS for finally coming to the party. As expected, GFS always comes in after a few days. back in a jiffy about the 12Z Euro and Kirk!
In the words of McCoy….D*****T Jim! I’m a Doctor not a Meteorologist!
uh oh…we’ve had mention of Kirk and warp (as in atmosphere in Kevin’s last post)in this thread…could mean trouble (with Tribbles)!!
Euro goes way west…
something’s up…West as in west of Nawlins coming on shore around Chuck Pond
http://www.meteo.psu.edu/~gadomski/ECMWF_12z/ecmwfloop.html#picture
hour 144 Issac is due south of New Orleans heading NW and is weaker compared to Weds. runs
coming on shore between Lafayette & Port Arthur TX on Aug 30 then to Texas for a drought buster. HUGE CHANGE IN MODEL!
So much for the models coming into line …
Kevin, how does all the westward movement affect our weather in SWVA next week?
Adding to the Star Trek themed comments, I think the Data will help to Spot the landfall location more toward the end of the weekend. Hopefully it’s not a Crusher and some sort of Impulse helps keep it from Warping into a major hurricane and impacting free Enterprise in the US. But perhaps it will Risa to the ocasion of helping the drought. And while my neighbor’s last name is Warf, a Klingon is actually far friendler than she is.
I think Isaac has changed his mind since he found out we were not inviting him to our family reunion.
I am now getting the impression that Isaac is either going to hit South Texas or disappear completely. I was looking forward to getting quite a bit of rain out of Isaac. So much for that pipe dream!
OK, the Euro is a very good model, probably the best for long-range tracking — but it has bounced back and forth between landfalls at New Orleans, the Florida Panhandle and the Texas-Louisiana border in just the last 3 runs. Let’s don’t etch it in concrete just yet.
The National Hurricane Center has nudged its projected track for Isaac a little west at 5 p.m.:
http://www.nhc.noaa.gov/graphics_at4.shtml?5-daynl?large#contents
Here is the 12Z cluster of tracks on the hurricane models:
http://raleighwx.americanwx.com/models/atcf/12zatcflateinvest1.gif
And the 12Z GFS Ensembles cluster:
http://raleighwx.americanwx.com/models/atcf/12zatcfensinvest1.gif
And the 18Z hurricane dynamic model cluster:
http://raleighwx.americanwx.com/models/atcf/18zatcfearlyinvest1best.gif
GFS and hurricane models have shifted west of the Florida peninsula, mostly. That is similar to the 12Z GFS operational model and the 0Z Euro run. Yesterday’s and today’s Euro 12Z runs are much farther west. Will the other models chase the Euro? Or will the 0Z Euro idea come back into play and split the distance with the other models?
There are some details that could change this, but generally speaking, the farther west of Mobile, Ala., or so it tracks, the less direct impact our region would likely see from it. The Florida Panhandle region would likely bring the low very near an Appalachians track, and that typically soaks us. Hitting the peninsula of Florida probably would swing the bulk of the rain a bit east of us, perhaps through central and eastern Virginia. These are sweeping generalities at this point that could change with details of frontal placement and location of upper-level troughs and high-pressure centers that cannot be precisely located a week in advance.
I love how sometimes people look at one model and all of a sudden dismiss the whole scenario playing out here…. it happens with snow storms alot, and now with hurricanes…. chances are at this time Saturday we will be talking about a whole different equation….I for one am guilty of this sometimes, but then I have to sit back and realize that we are days away from a landfall, and things will change alot between now and then….
18Z GFS still on track for FL Panhandle/Alabama Coast for a Florabama Slamma http://www.meteo.psu.edu/~gadomski/AVN_18z/avnloop.html
Anyone want to bet the Euro on the next run comes back east?
Nice trekking there Other John. You’d be one intestested in my story. Paramount Pictures stole my idea of First Contact in 1995 and used it for the movie, “Star Trek – First Contact” in 1996. I really should have protected that paperwork with a copywright……might have made some money. Took me a while to get over that one.
Looks like some of the parched central U.S. is headed for a non-tropical-related dousing in the next few days:
http://www.hpc.ncep.noaa.gov/qpf/p120i00.gif
Lots of dark red areas on Drought Monitor map linked below covered by some shades of blue and purple above.
http://www.droughtmonitor.unl.edu/
Hey Other John, John I talk to on Facebook, Nick from Ellet Valley, Rick, and all you other typical winter peeps I missed:
Check it out:
http://forecast.weather.gov/showsigwx.php?warnzone=MTZ002&warncounty=MTC029&firewxzone=MTZ105&local_place1=&product1=Winter+Weather+Advisory
First winter headlines of the season for the lower 48!
Nice find, Zach. I visited Glacier in the early 90′s. Got within 100 yds of a grizzly tearing into a beaver lodge. Another hike, saw a wolverine at 150yds……that’s close enough. Great park.
My third favorite meteorologist (behind Myatt and Singleton..but then again, Corfont sure is pretty to look at!) is on duty at the Weather Channel. He always has frank, unopinionated weather information in laymans terms (like we get here). Check out Jim Cantore. I believe AccuHenry is S-O-L on his hype for an eastern Florida landfall, and I’m normally a fan of his. I’m not seeing much of a northerly turn yet..Isaacs definitely going into the Gulf.
Quagmire-you say Isaac will be “Huge”? You are really out on a limb here, as I have not seen any legit reason to think it will be any larger than a Strong Cat 2 or Weak Cat 3 at best when it makes landfall in the gulf coast states. And the comparisons to Camille/Katrina made yesterday seem to really be a stretch. But in the end, if you are right, you certainly will get credit for calling it first.
Matt: I can’t claim to be a meteorologist — degree and career are in journalism — so the others can move up your list a notch!
Blacksburg Mike: National Hurricane Center would definitely agree with you, at least through 120 hours — no more than a 2 percent chance of even attaining Category 3 strength, per table below. (It has a 21 percent chance of dissipation by Tuesday!)
http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/234951.shtml?table?large#contents
A more westerly track into the heart of the Gulf for a longer time might raise these percentages.
A cool lightning display from the tall clouds just north of Hokieburg tonight.
That really stinks, Rick…and that was my favorite of the TNG movies.
Zach, I would be the same John from FB…I can’t wait for snow…
Some of northwest Roanoke/adjacent Roanoke County had a little pop-up storm about 5 p.m. Airport reported thunderstorm at that hour, but no official rainfall.
Saw some of that lightning blinking in the clouds to the west of Roanoke about 8:45 p.m. on my way back into the Roanoke Times office.
New Orleans to Panama City looks to be the target area.
http://www.ral.ucar.edu/hurricanes/realtime/plots/northatlantic/2012/al092012/track_early/aal09_2012082400_track_early.png
That’s one of the worst regions for storm surge potential. Long shallow water for several miles out to sea really augments the waves.
NW-moving storm into that region probably would not have much of a direct impact on us, though it might get caught up by a front and move our way a couple of days later.
Anyone on Twitter who is interested in hurricane reconnaisance flights should be following @HRD_AOML_NOAA. This is NOT the Air Force reconnaisance but some special flights being conducted by NOAA. They have been live-tweeting on their flights in and out of Tropical Storm Isaac.
Good light show from West Virginia tonight too…
Here’s some idea of where the GFS Ensembles (series of slightly different model runs from GFS) take Isaac not only to landfall but afterward. Many of those tracks would bring at least some of the moisture our way. Some would bring a ton of it.
http://blog.memphisweather.net/2012/08/thursday-evening-update-on-tropical.html
On the above comment, I tried to link a graphic within the blog. Let me see if I can go find the original. The blog entry is interesting looking at Isaac from a perspective west of us (Memphis).
Not quite the same graphic, but similar idea:
http://wxtalk.files.wordpress.com/2012/08/08-22-12-isaac-gfs-ensemble-tracks.png
The article was a good read.
Other John and Hokie Trax, I was out walking the dogs and saw the skies lighting up. I didn’t get a chance to check radar but I thought it was north of Blacksburg. Yep – I saw it from up here on the ridge!
Coyotes here are becoming more vocal lately. It either means the weather is changing or they are striking out on their own and claiming their territory. Have heard them twice this week.
Hurricane center shifts west with track. Center of cone is Alabama-Mississippi Gulf Coast. New Orleans is in it. Tampa barely is, now.
http://www.nhc.noaa.gov/graphics_at4.shtml?5-daynl?large#contents
NHC projected track reminds me most of Hurricane Georges in 1998.
http://weather.unisys.com/hurricane/atlantic/1998H/GEORGES/track.gif
Pronounced “Zhorzh” NOT the plural of “George.”
In other tropical news, Joyce has already been demoted to a depression. She’s been sucking on some dry air. May regain storm status later, but expected to curve away from the U.S.
http://www.nhc.noaa.gov/graphics_at5.shtml?5-daynl#contents
Too bad they don’t give firestorms names. In many tv shows and in the S.T. movies, Capt. Kirk would often yell, “FIRE!!”
It sure looks like Henry Margusity has continued the amusing, nearly always entertaining Accuweather tradition of laying a big fat egg with outlooks and predictions. Henry claimed Isaac is headed up the east coast of Florida? Think again, HM. I just watched Brent Watts on “7″ and he showed the forecast tracks of about 8 models, and they were in general agreement. If those models are correct, Isaac will be heading in the general vicinity of the Gulf Coast of FLA, not the Atlantic side. Zippo had it going over the Atlantic coast or even up the middle of FLA.
Quags, I haven’t looked at posts past roughly noontime today, but like you I am fearful that Isaac will indeed strengthen quite a bit if it stays west of Florida, and get to be at least a “2.” But I do not know the reasons why some trop storms or hurricanes go berserk once they get into the Gulf, while many others don’t strengthen all that much. I need a tutorial from KM on that. Maybe he can expand on that in the upcoming days. I bet what the winds aloft are doing play a role in that.
Slight adjustment to my 11:49 PM comment. When I typed “in the general vicinity of the Gulf Coast of FLA” what I meant was that one or perhaps two models had a Fla. Gulf coast landfall while all the others took it west of Florida’s “west coast.”
Kevin, thanks for linking to the descriptive article by blogs Memphis weather. In the 5th map, the one in green and violet, a couple of those tracks were eerily similar to Camille. Making a Miss. or Bama landfall, going north, then a sharp turn east through KY into Virginia.