Meteorological obsession for the next week: Isaac
Already on the front-burner for America’s weather-interested, Tropical Storm Isaac — very likely soon to be Hurricane Isaac — is going to shout down all the politicians this week on your TV. In a way it already has, with the planned delay of any real action at the Republican National Convention in Tampa until Tuesday afternoon. The track of Isaac has been steadily nudged westward, so much that Tampa will probably only get a glancing blow on the low end of tropical storm status. But Isaac, having successfully dodged the mountains of Hispaniola and Cuba, now finds an open field of almost-hot ocean water, no land masses bigger than the Florida Keys and stable conditions aloft that will likely charge it up into a hurricane fairly quickly and possibly a major hurricane (Category 3 or stronger) or almost one before making landfall on the Gulf Coast late Tuesday or so. New Orleans to Apalachicola, Fla., seems to be the most likely spot for landfall, a slice of coast that has been blasted in the past few decades by the likes of Betsy (1965) and Camille (1969) and Frederic (1979) and Elena (1985) and Opal (1996) and Ivan (2004) and Katrina (2005), to name only a few. It’s very likely at this point that Isaac is going to be a big deal, potentially a very damaging hurricane with a large storm surge, and it may continue to be a big deal well inland, with flooding rains and a tornado threat extending far from the coast. Whether that shifts more toward the Tennessee and Ohio River valleys or more toward our region — or both — remains to be seen, as it depends on how an approaching low pressure trough/cold front and a high pressure system to the north interact with Isaac. Right now, you can pencil in a chance of rain for Southwest Virginia related to Isaac for Thursday and Friday. Even if the bulk of Isaac passes west, it may be positioned to pull in some southeasterly winds against the mountains to enhance shower chances — or its remnants could arrive a couple days later, pushed along by a cold front. As is typical with hurricanes and winter storms, you’ll see and hear lots of back and forth this week as various models and well-known forecasters offer different scenarios (I’m sure we’ll post a few on here in comments from time to time, as we have through the weekend). Keep up with the National Hurricane Center for the latest warnings and projected track.
As the week goes along, we’ll take a closer look at the potential effects for Southwest Virginia. Other than possible effects from Isaac, the week looks pretty normal, highs in the 80s, lows in the 60s, and some sporadic showers and storms. Often, this scattered activity tends to dry up a bit as a tropical system moves into the Gulf, as more moisture is consolidated near the tropical system and high pressure builds in response to the deepening low pressure with the tropical system. With a little more sun, a stray 90 or two may be possible for afternoon highs a day or 2 early to mid week — hasn’t happened at Roanoke since August 8.
August 25, 2012 - 11:58 PM
RSS feed 
Will be off the blog some Sunday for family time. Gonna be a busy week ahead! I’ll check in and approve comments every now and then, though.
Another nudge west on the official National Hurricane Center projected track.
http://www.nhc.noaa.gov/graphics_at4.shtml?5-daynl#contents
Not that we don’t need the rain, but every westward nudge put’s the storm where it’s most needed.
Not sure anyone needs 8-17 inches all at once like the HPC is showing for Georgia/Alabama/western Florida Panhandle.
http://www.hpc.ncep.noaa.gov/qpf/p120i12.gif
The remnant low will probably curve back eastward at some point after landfall.
Morning satellite still shows the swirl of clouds over Virginia marking the low that moved inland on Saturday.
http://www.ssd.noaa.gov/goes/east/wfo/rnk/vis-l.jpg
Saturday’s low put 1.96″ in the bucket down this way. Still cloudy & cool here this AM.
Looks like my favorite beach bars will be getting hammered, especially the Florabama Lounge.
I forgot to post this link to the Florabama Lounge:
http://www.florabama.com/
If you click on play the You Tube video on the home page, it shows the damage Ivan did in the area back in ’04. God Bless my Gulf Coastal Brothers & Sisters. Get ready for Issac!
Any Issac obsessors, nice tweet listing on TWC site. Lateset NHC forecast further west although highly uncertain
Updated 11:00 AM National Hurricane Center Advisory for Issac:
http://www.nhc.noaa.gov/graphics_at4.shtml?5-daynl#contents
A HURRICANE WATCH IS IN EFFECT FOR…
* EAST OF MORGAN CITY LOUISIANA TO INDIAN PASS FLORIDA…INCLUDING
METROPOLITAN NEW ORLEANS AND LAKE PONTCHARTRAIN
A TROPICAL STORM WARNING IS IN EFFECT FOR…
* THE CUBAN PROVINCE OF VILLA CLARA
* THE NORTHWESTERN BAHAMAS
* THE FLORIDA EAST COAST FROM SEBASTIAN INLET SOUTHWARD TO OCEAN
REEF
* LAKE OKEECHOBEE
* THE FLORIDA WEST COAST AND THE FLORIDA PANHANDLE FROM NORTH OF
BONITA BEACH TO INDIAN PASS…INCLUDING TAMPA BAY
Of note, NHC now thinking landfall in the Gulfport/Biloxi MS area as a Category 2 late Tuesday night/early Weds. AM. If you live in the New Orleans to Mobile/Pensacola area, time to get moving now!
Sunday’s 12Z GFS Operational Loop is a catastrophic disaster for New Orleans & LA Coast.
http://www.meteo.psu.edu/~gadomski/MRF_12z/mrfloop2.html
Per new GFS run, landfall will be south of Nawlins in the Houma/Leesville area which is a worst case scenario for the Crescent City as the ESE winds will funnel the storm surge into Lake P’train just like Katrina did. Remember Katrina was Cat. 2 when she hit NO. Points east of Mobile look to be less of a direct hit but will see Tropical Storm conditions. Issac then drifts west towards Houston then north to DFW-OKC then curving ENE over the Midwest & New England missing the Mid-Atlantic altogether.
Correction: My bad again…Katrina hit New Orleans as a Cat. 3 not Cat. 2
@ work…have to be brief…KeyWest..last hour..east wind 24gust37 kts…steady increase last 4 hours.
And the forecast track has been nudged even farther west:
http://www.nhc.noaa.gov/graphics_at4.shtml?5-daynl#contents
The central spin of Tropical Storm Isaac can easily be seen on Key West, Fla., radar loop.
http://radar.weather.gov/radar.php?product=N0R&rid=byx&loop=yes
Pretty soon the forecasted track will be in New Mexico.
So, which model and forecaster wins the cupey doll from a week ago when the track was all over the gulf, as far as accuracy? Gonna be a lot of red faces in a day or so. No really unusaul tho.
“Not really unusual tho”. If I ever had a strong suit, it was in poker, not spelling.
Also of interest on the 12z GFS… if you look waaaay out at hour 144, there is another system (is it the soon-to-be Kirk?) coming into the picture southeast of Puerto Rico. It seems to be making a quick turn to the North, staying off of the American coast before making landfall in the maritime provinces of Canada.
12Z Euro Operational Loop for Sunday PM:
http://www.meteo.psu.edu/~gadomski/ECMWF0.5_12z/ecmwfloop.html
Euro holds onto Mobile Bay Landfall on Wednesday then stalls over Lower Alabama (the other LA) on Thursday then drifting east of Memphis on Friday before meandering into the Midwest for the weekend.
Somehow, Kirk has been left in the dust & now is a fish storm.
18Z GFS Operational Run for Sunday:
http://www.meteo.psu.edu/~gadomski/MRF_18z/mrfloop2.html
Kevin, Brandon…someone please verify that this run is a mirror image of the 12Z run. Also Kirk is still in the picture coming very close to OBX on Friday Sept. 7 then going to stir up some fish.
Let’s let it get to shore in the Gulf before we crown a champ, WD. But it seems like the early Euro runs last week were closer with what is likely to be the track of the storm into the central Gulf.
I think the new 5-day precip map from the HPC is way off base. Isaac’s moisture is clearly going to impact Arkansas and Missouri before it curves east to get us a couple of days later.
http://www.hpc.ncep.noaa.gov/qpf/p120i00.gif
The heaviest rain is often east of the center. If the center goes into eastern Arkansas, the heaviest rain may be where HPC depicts it. However, it may well be that the center goes even a little farther west.
Looks like the Day 4-5 map is banking on some upslope flow into the Smokies enhancing rain totals there.
http://www.hpc.ncep.noaa.gov/qpf/95e00p48iwbg_fill.gif
I think the center of circulation will be right over Arkansas in a few days……….and I might be right.
Last two GFS runs take center of circulation all the way to Oklahoma.
Strangely, Euro is now on east side with Mobile, Ala., landfall, while GFS has shifted west almost to Texas-Louisiana border.
I see the shift to the west again that Kevin’s mentioning above, but I can’t shake how creepy it is to see a storm heading for this region on the exact anniversary of Katrina.
Quags, concerning your 1:31 PM cpmment, not only was Katrina a Cat 3 at landfall, but I am pretty sure that it was “top-end” CAT 3 at either 125 or 130 mph. It had been a Cat 4 (140-145 mph winds) when its eye was within 20 miles of landfall, with lots of the winds in the windiest NE quadrant pounding Miss. and ALA. THAT last sentence I am quite sure of, about it being A CAT 4 just before landfall. I forget my scanner, satchel, beverages, you-name-it, once in a while at my postal job, but I can remember all kinds of stuff from my long-term memory. I just saw a TWC special on Katrina that was both fascinating and terrifying. Actual home and news report videos.
wd, unless Asimov makes a VERY unexpected turn in the next 36 hours, I would definitely nominate the Euro as being the best model, and Henry Margusity for having the worst prediction, claiming Asimov would go up the east coast of Florida. Quags gets a lot of credit, too, for predicting very early on that it was likely to hit at least as far west as the FLA panhandle.
Rick gets some credit, too, for pointing out the fact at least 3 days ago that Asimov would have to deal with dry air in the eastern Gulf. TWC folks just mentioned that this evening, saying that Isaac has been fighting that throughout the past couple of days. Good thing that dry air was there. Otherwise Isaac might have gone on steroids and “pumped himself up,” as Arnold Schw. used to say. And even the COLC may claim a little credit, too, depending on how windy Isaac becomes.