Let’s avoid the temptation to compare our June 29 derecho to Hurricane Isaac
Wednesday’s Weather Journal column: Summer 2012 as a whole not all that hot for Southwest Virginia
Officially estimated sustained wind speeds around the eye wall of Hurricane Isaac are 80 mph very early this Wednesday 
morning. You probably remember that Roanoke’s maximum wind gust in the June 29 derecho was 81 mph. I alluded in the last post to the similarity of wind speeds just to give at least some idea of comparison how the wind was blowing. But let’s resist the temptation to go beyond that in comparing the storms. Roanoke’s 81 mph gust was just that — a gust, not a sustained wind speed. It was the highest officially recorded in Southwest Virginia, and all of National Weather Service-Blacksburg’s forecast area, during the derecho. Wind gusts at Blacksburg and Lynchburg did not break severe criteria of 58 mph. (Scroll down about halfway in the NWS-Blacksburg’s official report on the derecho linked here to see local wind gust reports.) There were certainly much higher gusts away from the official instruments during the derecho, likely 80-100 mph, based on damage (blue dots on the inset map above mark damage or wind measurements of severe force, 58+ mph; black dots are those comparable to hurricane force, 75+ mph). Let’s also remember that when we see gusts reported at various official sites in Louisiana 
that seem lower than the National Hurricane Center estimates. There aren’t going to be many recording stations where the winds around the eye wall are greatest in the southern Louisiana bayous. Also, while the derecho was 15-45 minutes of straight-line winds out of the northwest, the hurricane will give hours of similar to greater sustained winds shifting from one direction to another. And we didn’t have 1-2 feet of rain and any ocean surge in the derecho. We shouldn’t downplay our derecho — it was a very severe storm system with widespread impact we won’t soon forget — but let’s not try to say our storm was worse than what Louisiana is experiencing. They’re different species, let them live in different meteorological cages.
There’s certainly no comparison between weather in Louisiana and Southwest Virginia this week. A cold front that sank south on Tuesday has reinforced our temperatures with a bit more dryness. Expect highs in the 80s 
and lows in the 60s, near late August norms, through the end of the week, with little or no chance of rain. The Hydrometerological Prediction Center special map for Hurricane Issac and its remnants, posted Tuesday evenings, shows the heaviest rain curving well west and north of our region. But it also shows rainfall of around 1/2 to 3/4 inch nosing into Southwest Virginia over the next 5 days. This would be related to a weekend cold front that may push some moisture related to Isaac into our region. We are not going to get the brunt of Isaac’s inland rains — parts of Arkansas, Missouri and Illinois will most likely be in the core of that, where it is so dry there is next to no concern about large-scale flooding despite forecasts of 2-5 inches of rain. But we may get a little bit of Isaac’s moisture, eventually.
August 29, 2012 - 12:42 AM
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Isaac has very good structure and is wobbling sort of in place — already has backed off of land back out to sea once. It’s spinning walls of rain and wind into southern Louisiana repeatedly. Don’t let the Tampa/New Orleans-centered media hype fool you — this will be a major disaster for some parishes in Louisiana, especially south and southwest of New Orleans. Some flooding in the Big Easy and along the Mississippi Gulf Coast, too.
Last evening I had one of my flights fly within
50-75 miles from the approaching outer band on the due north
side of Isaac.
They told me it looked at 37000ft like a gray wall.
What interested me was how far the circulation of Isaac affected
the weather flow of half of the U.S. The line of thunderstorms
that sat over southern Va much of the afternoon and evening
was the only area in the southern US that did not have a southwesterly
flow to it.
We here in the DFW area got a few popcorn showers that continued to
rotate into the Metroplex till almost dark. Isaac has a very
broad circulation to it. A few showers were only on one side of the airport. Causing aircraft to be able to land on one side…but not the other. Looks like tomorrow will be the same.
That area of weather thats bucking the trend over VA/NC is a huge factor in steering Isaac to the north at a crawling pace..This will be interesting to watch in the next few days.
Luckily the Mississippi was very low..many sand bars grounding large vessels. I think thats gonna be needed as this thing creeps along.
I woke up this morning to see that Isaac actually gained strength while 1/2 ashore. Looks like the big thing isn’t going to be Isaac’s intensity, but it’s duration. Hopefully most of those coastal areas are noting but swamps and marshes and there won’t be too much in the way of property loss.
I just watched The Weather Channel briefly, and while Carl Parker (I think he is a good guy, just presents the facts and the possibilities) was talking, it repeatedly showed a radar loop of the entire Louisiana and SW Miss. area between 3:15 AM and 7:05 AM CDT. It clearly showed where the center of circulation was, practically at the coast well south of New Orleans. The thing that stood out was how far the eye moved during that 4 hours ….. NOT AT ALL, at least as far as I could tell. Maybe 5 miles.
That radar loop also showed where the heaviest rains were, and the immediate New Orleans area was one of the hardest hit. One area called the New Orleans shoreline (shoreline of Lake Pontchartrain??) has already received 6.65 inches. Even if the recently reinforced levees hold in New Orl., there has got to be some street flooding in such a low-lying area.
Jesse Ferrell from Accuweather has a pretty neat article and several examples of Isaac from HRRR, something he says wasn’t around in 2005 when Katrina hit. Rather interesting..
Friends in Baton Rouge still waiting on Mr. Isaac. Some wind. Not much rain yet but I’m seeing that it is nearly stalled and could take the rest of the day to get to Baton Rouge. All that rain on the way is bound to hurt. One says lights are starting to flicker but they are prepared with a generator.
Looks like Baton Rouge is just about to get whacked with its first heavy squall band. And then keep getting whacked most of the rest of the day.
Isaac, so far, like Debbie has had the effect to cool the gulf waters considerably while causing little destructive wind damage. A lot of this heat energy was lost to space and a lot was transported toward the arctic polar region. General global cooling. Like Debbie, there is an atmospheric river flowing northward up along the western Atlantic. Debbie’s flow was almost due north while Isaac is more northeast. Enormous amount of heat loss and transport with these two storms only equaled by media hype that is where the most wind was generated.
But still need to keep an eye on Isaac because, well you know, it’s the weather.
It’s being reported on Twitter by NBC that the leader of Plaqumines Parish, in Louisiana is describing the surge and flooding going over 12-foot levee now as “worse than Katrina.”
About half a million are without power now. Wind gusts have topped 60 mph in the New Orleans area the last 6 hours — sustained winds generally 40ish. One unconfirmed 107 mph gust in Terrytown, La., just south of New Orleans.
The wind is rough, but as has been noted, it’s the water and the duration that are the big problems with Isaac.
It won’t be a Katrina on a large scale, with the same level of wind damage/storm surge over such a large area. But it may be a comparable water disaster for some parishes in Louisiana south/southwest of New Orleans. And some of those areas are getting the north/east quadrant of an eye wall this time, not the back side as in Katrina.
Some have discussed the nationwide wind pattern being influenced by Isaac, and here’s the best way to see it.
http://hint.fm/wind/
Doug, call me anything you like, but if you call me late for supper, then you are in trouble.
My brother in SW Missouri is getting pretty excited about the possibility of getting a couple inches of Isaac rain. They are in Exceptional (the worst) Drought.
Tropical Storm Kirk is out there. A fish storm. Sorry, Star Trek fans.
http://www.nhc.noaa.gov/graphics_at1.shtml?5-daynl#contents
Blacksburg Mike will find this interesting, since he momentarily called the current hurricane “Ivan” in a comment yesterday. AP just put on Twitter than Hurricane Irene was slamming the Mississippi and Louisiana Gulf Coast on the 7th anniversary of Katrina.
Something about the letter “I” with U.S. hurricanes.
Thanks, Rick, for allowing me permission. And the phrase about avoiding calling you late for supper was exactly what my Dad used to say. Thanks. Meanwhile, Kevin was the Link-Man with Kirk. I can just hear Shatner now: “Zulu (or was it Sulu?), where are you taking me?!?!?” Possible reply: “On toward morning, Captain.”
TWC showed someone’s neighborhood, probably in that Plaquemines Parish, and one small house was almost totally under water, and another house flooded up to the 2nd floor. Like a lot of us have been saying, this is a serious storm, although not in Katrina’s league. This is probably the worst damage from a hurricane or tropical storm in the USA since at least 2010, isn’t it, Kevin? (NOTE that I said “USA”).
Rick, thank you for the link to the Wind map. Amazing!
Kevin, I’ve seen the models forecasting most of the effects of Hurricane Irene/Isaac/Ivan to go north and west of us here in Roanoke. The storm appears to be moving slower than forecast at this point. If that is true, does that mean we have a better chance for rain from this storm or is it less likely we see any direct effects?
Patrick: Most of the forecast models are shifting a little west with the inland low of Isaac now that it is slowing down — so I don’t think it’s slowing down will have much effect on it getting to us. We may get some moisture from it when it ends up in the Ohio Valley over the weekend.
Doug: Irene last year is considered the 7th costliest hurricane in US history. Depends on how much you count inland flooding in New England into the total, I suppose.
Isaac has been a crazy and unusual storm to track. Seemed the core (eye wall) never had a chance to develop fully until right before the first landfall Tuesday tonight. It fought dry air as well, but once the core developed – like a foundation for a house, the storm was able to grow stronger… unfortunately right as the hurricane was moving ashore. Hurricanes also do their best to survive… in other words, the center will try to stay near open water as long as it can. We saw that today. Praying to the poor folks who were hit the hardest – I know they were told to evacuate though… but they are still people. Like any major weather event, meteorologists will take the unexpected and unusual parts of this hurricane and use the information to further our ability to forecast. Hats off to the emergency managers, NOAA & NHC for flying extra aircraft into Isaac for more info and to researchers who deployed mobile radars near the storm to gather extra data that may one day help us with the next storm.
“The center will try to stay near open water as long as it can.”
Im not sure I understand the intent of this idea.
It almost sounds like thats an opinion that a hurricane has willful
guidance.
Hurricanes are guided by relative pressures surrounding them..coriolis
effect and upper winds.
All weather moves by trying to seek atmospheric equalibrium.
Just like the Mississippi flows south ..its not willful…just seeking balance.
I guess Monday is when some of Isaac may get to us? The heaviest moisture might get rung out in WV just before it gets here, accroding to the CPC.
http://www.cpc.ncep.noaa.gov/products/predictions/threats/hazards_d3_7.png
Continuing to remember Camille, the latest model guidance is provocative.
NHC follows CFDL and HWRF north (but not as far as they go west). All the other models on this graphic expect Isaac’s remnant to turn east and veer south, toward us. http://www.skeetobiteweather.com/picservice.asp?t=m&m=09&av=4
I’m glad that I ended my 12:44 comment with a question. Thanks, Kevin. I just looked up Irene, and now Mr. Negative Memory (me) remembers. “Goodnight Irene” was the one I serenaded, but which turned her back on SW Virginia and nailed the barrier islands of NC. Wiped out more than one bridge, if I remember correctly (which would be “for a change”).
Is there any website you would recommend Kevin or anyone, to find out how much of the dollar damage was done in NC, and how much in New Jersey, and how much in the western New England states (A lifelong friend just told me a few days ago that Vermont was hit pretty hard, with several rural bridges getting destroyed or badly damaged.)? Probably over 80% easily in NC with long bridges getting swept away…
joe, I also was a bit puzzled by Jamey’s comment about the hurricane trying to stay near open water. I hope that he re-visits here and explains. I have seen lots of trop storms and hurricanes make landfall and keep right on going inland at very good speed (see my comment above about the 1938 New England hurricane …. it raced through New England).
Above Rick commented that his brother is waiting hopefully for Isaac to pay him a visit in Missouri. Kevin, have any of your loved ones, friends, etc. in Arkansas gotten in touch with you about at least some possible drought relief?
Wikipedia has an article on Irene. Wikip. claims that it was the 5th costliest hurricane. Maybe it is including the estimated $500 M pricetag for Puerto Rico, whereas your source Kevin (NWS? NOAA?) is not. Anyway, the US total was estimated to be $15.6 B, probably not including Puerto Rico, because it was listed separately. Further on down the article Wiki claimed that the Irene damage was $19 B, just a bit more than Ivan’s $18.8 B. Weird numbers. However one analyzes her, Irene was one very, very bad girl.
At this point I’m not sure Isaac will remain a recognizeable entity even if its old low center turns our way eventually. Likely the moisture gets spread out as it comes inland, and the old low center of Isaac slowly unwinds. Camille in 1969 remained a rather tight-circulating depression all the way from Tennessee to here — and actually started re-intensifying when it could draw a little inflow off the Atlantic.
But you gotta keep an eye on old tropical systems. Some very strong storms wither quickly while other fairly weak ones keep on chugging well inland.
Watching the far outer bands of Issac in Georgia and hoping that it is bringing some relief to their drought.
joe, what’s the word on how Texas will fair on this? Extent and where?
Looks like Issac might curl our way by late in the weekend.
http://www.hpc.ncep.noaa.gov/qpf/p120i00.gif
Look at this cold air mass building in central Canada 10 days out on the 12Z Euro.
http://blogs.roanoke.com/weatherjournal/files/2012/08/TempAnomaly12ZEuro10days.gif
Don’t know if it’s right or not, but it will be fun to look at for fall lovers.
Very little if any effect on Tx..
Far east Tx in the piney woods west
of Shreveport may get a bit of rain
and some gusty winds but nothing unlike
what they would get in a average thunderstorm.
We here in Dallas are getting surface winds around
the circulation..050 at 12 kts now…(out of the northeast).
Could affect air travel if they get too much of a crosswind
if it nudges more to the NW. Our main runways here are north-south.
It would surprise me if we even get a 30 knot wind.
Shreveport last hour has winds from the Northeast 16 with gusts to 26..
Dallas forecast now for mid morning tomorrow winds from due north..
13kts gusting to 23 kts…no precip in forecast.
Interesting that there was a storm named Irene in 2005 and 2012. WUWT?
Make that 2005 and 2011.
Looking at that area of cold air in south central Canada reminds me …. I think I will peek at the NAO and AO and see what they have been doing and are expected to do. I think the last time I looked at least 2 weeks ago they were both close to neutral.
But meanwhile poor Louisiana and the Gulf coast counties of Mississippi continue to get dumped on. I think someone in Biloxi claimed that the storm surge was 10 feet in one spot in that area.
Wow. Really weird stuff on the GFS outlooks page for the AO. AO dipped into negative country for about 5 days in mid-August, but has been alternating around the 0 level since then. I will try to post a link (Postal Link-Man!!) to that GFS Outlooks. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_mrf.shtml Note that the 10-day outlook takes the AO right through the floor for 3 straight days starting (I think) on the 4th.
The hurricane name list for the Atlantic is recycled every six years. The World Meteoroloigcal Organization decides every year which storms have become deadly/destructive/infamous enough to have their names retired from the list. Irene was retired after 2011.
Scroll down a bit on this link for a list of retired names:
http://www.nhc.noaa.gov/aboutnames_history.shtml
The NAO continues to alternate between dips well into negative territory and then rebounds in a positive direction, but not above the zero line. Amazing. The NAO has not been positive since May, except for a couple of two-day blips into very small positive readings. This would possibly be Winter 2009-10 all over again if this had been winter. The 7-day GFS outlook for the NAO shows a 3-day bubble into positive readings starting on Labor Day, but the 10-day and 14-day outlooks do not agree, showing a persistent (slightly negative) bias. The Postal Link: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index_mrf.shtml
We haven’t had a truly cold autumn since I moved here in Oct. 1997, at least that I can remember. I remember that autumn 1976 was unusually cold (what Yankees call “early”), and it DID lead into a very cold winter …. the brutal winter of 1977. But I doubt if there is any reliable relationship between a cold autumn and a cold winter …. even if by a rare circumstance we got one (a cold autumn, that is). Of course the Snow Haters are rooting for a cold November ….. November 2009 especially and November 2010 (the latter after Nov. 7th) were warmer than normal, but lead into cold winters.
Goodby Isaac. You created somewhat of a stir but now you’ve lost your heart so go sprinkle your remains across the mid west.
From the 4 pm CDT NHC Tropical Storm ISAAC Forecast Discussion:
“THERE REMAINS NO INDICATION IN ANY OF THE NHC MODEL GUIDANCE THAT ISAAC WILL BE ABLE TO ACQUIRE ANY BAROCLINIC ENERGY THAT COULD CAUSE IT TO STRENGTHEN INTO A SIGNIFICANT EXTRATROPICAL LOW WHILE IT IS OVER THE UNITED STATES.”
Kevin, what is baroclinic energy?
Mark: Basically, the energy developing along a boundary between contrasting air masses. Most of the more substantial inland remnant lows from tropical systems convert in this manner.
It would be unusual for a late August hurricane to become a strong extratropical low over the continental U.S. because of the typically stagnant late summer air patterns. This is more likely to occur in late September and October.
Don’t know if anyone else caught it, but my family saw a large meteor tonight in South Rke County. Looked like a green-tinted fireball. Quite a sight!
Just saw a report of the the same meteor on Twitter from North Carolina.
The CPC (Climate Prediction Center) has also picked up on the possible movement of that cold air into the east-central USA on the 8-14 day outlook. Take a gander (or “goose,” … or whatever): http://www.cpc.ncep.noaa.gov/products/predictions/814day/index.php
Missouri, Iowa, Illinois, southern Wisc., Indiana, KY, OHIO, WV all in the 40% chance of being cooler than normal. All of SW Virginia (VA west of the Blue Ridge) seems to be in the 33% area.
Maybe I won’t be returning to work on a full-time basis during a heat wave next Wednesday. I work this Friday, and it may be only the 2nd day of August 2012 in Roanoke that reaches 90*. TWC is predicting 92. I bet NWS is in the upper 80s on their forecasts. I hope TWC is wrong.
Anyone else have a problem during the last few hours logging onto the Weather Underground website (www.wunderground.com)? I first tried the NEXRAD radar, then the forecast for ROA, and got a screen that I have never seen before, and that did not allow me to get out of it.
Mike, I don’t know why you are saying goodbye to Isaac in your 9:02 PM comment. Perhaps because he/it is no longer a hurricane and there is no longer an eye? But the circulation around Isaac right now and for the past 12 hours or so is MUCH better organized than practically the entire time that Asimov was over the Gulf, or even before then.
Also, I saw a forecast rainfall map for the next 5 days, and interestingly it showed that SE Iowa was expected to get 4+ inches from the remnants of the I-boy. Lots more rainfall and power outages will be caused by him, methinks.
About to discuss likely inland consequences of Isaac in new blog post.
looks like so far most people that saw it were
right at the VA/NC border..
http://lunarmeteoritehunters.blogspot.com/
That little weather system in central Va last Friday applied about +- 4 ” of rain in some areas. I think it was quite a bit more along the coast. When I saw the radar images it looked like it covered about 10 – 12 counties. That was weather. Where was the Weather Channel hype?
We will see next week what the rain totals are for TS Isaac. We all know where the Weather Channel was on this one.
I am 6 ft tall and can reach almost 8 ft. I can jump to reach 10 ft. I would expect to see storm surges as high as I can reach if I lived on the gulf coast. Expect it or move.
Why do I think of a submarine with screen doors when I think of New Orleans?
I just checked the National Weather Service report for the New Orleans International Airport. As of this post the three day total rainfall is 8.31 inches. The max wind was around 45 mph with some gusts to 68 mph over a 4 hour period.
There are some folks suffering in Plaquemines Parish, Louisiana, tonight with loss of property. I just refuse to downplay their plight because it wasn’t a worthy enough hurricane or because they live near a coast. Also 600,000 without power. That’s 20 percent of the June 29 derecho outages, but it may not be done yet. As the storm moves north, even 45-50 gusts from the east on deciduous trees braced against west winds naturally will cause additional power outages.
New Orleans is where it is because there has to be a city there to populate critical shipping infrastructure for the nation. It doesn’t necessarily have to be a city of a half-million as it was pre-Katrina, but there has historically been an important city there and will continue to be as long as we produce oil and ship and receive merchandise around the world. And it will continue to get hit by hurricanes from time to time, about once every 8 years historically has one passed within 50 miles of New Orleans.
As for whether this was hyped on TV networks too much or not, I will leave to the media critics.
Heres an article from the WSJ..
Note that as Isaac makes its significant
easterly turn brought about by upper winds
and an increased pressure gradient from the
Northwest its rainfall potential jumps
to a forecast of northwards of 7 inches
for northern Ky and Wva..
Stay tuned.
http://blogs.wsj.com/dispatch/2012/08/30/though-isaac-weakens-rainfall-still-enormous/
Kevin, I’m sure you have probably looked at this.
http://www.ospo.noaa.gov/data/sst/contour/gulfmex.c.gif
I have followed the claims of CAGW and got quite interested in the atmospheric and ocean circulations and temps. Always check out sea temps behind a storm system. Debbie and Isaac were real chillers.
The IR maps showing out flows from a storm system reveals tremendous heat energy transport. Debbie, while nearly stationary for many days produced an atmospheric river in the sky up the Atlantic coast to the Arctic region.
A question that I have pondered much is (considering all caveats): How much water is suspended in a hurricane, or, how much is evaporated from the sea over a given time frame? Thinking in terms of cubic miles H2O? How could I calculate a reasonable estimate of the heat loss through radiative transfer to space from the satellite IR images? Watts/meter^2/time frame utilizing the satellite data?
With regards to the outflow to the east of Debbie or Isaac, would the equivalent condensed water be equal to the flow over Niagara Falls? More? Less?
I haven’t been able to find the sources of information if it in fact exists. I could possibly do some general mathematical guesses for some vague idea but I sure someone somewhere more motivated and knowledgeable has attempted to quantify this. Any links or discussion would be appreciated and that info will be added to my vast wealth of useless knowledge!
Inquiring minds want to know. I think you will get the gist of my inquiry. Kevin, feel free to email me if you like.
Mike: Glad you posted that sea surface temp map link — so much so, I’m going to post it on the newest blog thread when I get it up later. We pay a lot of attention to this before a storm, interesting to see it afterward.
Let me see if I can find something for you on this. Somewhere I’ve seen an estimate on hurricane/water suspension/evaporation — of course, it will vary from storm to storm, based on size and other factors.
You may need someone with a more technical physics background for some of this. But let me see if I can you get rolling the right direction.
Thanks for the reply.
The primary link to get that chart is:
http://www.ospo.noaa.gov/Products/ocean/sst/contour/index.html