Weather Page of Jim Blowers

Hurricane Coming?

I heard on the news recently that a tropical wave way out in the Atlantic has become Tropical Storm Fabian, and just tonight it became Hurricane Fabian. It is way out to sea but I want to see if it would affect where I am living (in central Virginia). So I checked the hurricane sites such as Weather Underground's site. It shows the future track of the tropical storm for a few days and shows that it will skirt north of the Caribbean islands, such as the Leeward Islands. But that's not far enough. I want to know if it will hit the mainland United States, and if so, where. There are two sources of this. I tried the Global Forecasting System first. I checked it two days ago and it said that Fabian, which I suppose will become a major hurricane, will hit Miami, then go in the Gulf and hit Fort Walton Beach, Florida, then go off to the northwest and peter out and not affect central Virginia. I checked it again today. The forecast has changed. The 384-hour forecast shows that Fabian will approach Florida, turn up to the north, strike the Wilmington, NC area and make a direct hit on central Virginia. We hardly need this here in Virginia. We have had enough rain this year, and a 6-10 inch deluge, which is what this storm would produce, would cause massive flooding all over the place. I also checked Gary Gray's discussion and he says it may come up the Eastern seaboard, saying that the GFS scenario has Fabian first "taunting Florida" then "slamming hard into the Carolinas". But he notes that there are other models that take it out to sea, and still others that cause it to go poof midsea, sort of like Debby did near Hispaniola in 2001.

I will be monitoring this storm carefully. The local news media don't mention it much at all, and it could conceivably go another way. But it seems like it is going to become another Fran or Floyd. Watch out for those F storms, those storms that have an f-word for their name, such as Fabian. By the way, these links are likely going to become different or invalid in a few days.
posted by Jim on 8/29/2003 04:47:02 PM

Isabel and the GFS [Report 1]

It's late summer and early autumn, so it's hurricane time. And sure enough, there are two hurricanes and two tropical depressions out there. Hurricanes are rather unpredictable creatures. For example, take Fabian. It looked like it was going to curve to the north and go out to sea, and so not harm any land areas. Well that it did, but it unexpectedly gave Bermuda a direct hit, and now they are cleaning up the mess there. It's gone but there is another storm out there, Isabel. It is following the path of Fabian. So where is Izzy going?

It is way to the east of the Leeward islands, and so it will take several days even to get there. After then, will it go out to sea or will it hit the US or somewhere else? This is way off in the future and so a weather prediction or model system is needed that will go out as far as possible. NOAA's Global Forecasting System or GFS goes out to a whopping 16 days! That is time enough to find out what happens to Isabel. For a while GFS was saying that it was going to go out to sea. Then Gary Gray pointed out that the 2003 September 7 12Z (Z means Greenwich Mean time or Universal time) run of GFS shows Isabel slamming into New England, creating a new version of the Great New England Hurricane of 1938. This would happen about two weeks from now, around September 21. Gary Gray points out that he has no confidence in this forecast, because it is so way out in the future.

Indeed, future runs show other things. The 2003 September 7 18Z run shows Isabel once again going out to sea, and the 2003 September 8 0Z run shows it slamming into Nova Scotia and Newfoundland. The 6Z run today says it will go to Ft Lauderdale, Florida, then head into Tennessee, join up with an ordinary low, and create the biggest floods this country has seen since Agnes in 1972. The 12Z run shows it hitting midway between Massachusetts and Maine, and the latest run, 18Z, is even more horrendous. First it heads into the Delmarva Peninsula, right into Baltimore's inner harbor. Then it goes up the Delaware River, into Pennsylvania and New Jersey, giving New York City a big whack. Then it curves into New England. If this happens it will be the most destructive hurricane in history, because this area is heavily populated with a lot of development.

The point here is that the forecast is all over the place. It could hit Florida, it could hit Virginia, it could hit New England or Nova Scotia, it could go out to sea or even hit Bermuda again. That is why we don't see this on the TV weather report. The TV weatherman's job is to predict, and watching a model go from here to there as newer editions go out is not predicting, which requires saying definitely where it will go.

But nevertheless it is interesting to watch the forecasts. In a sense there is a virtual storm out there, hanging in the future, hitting all these places as time goes by, and as the storm gets closer, its variations will damp out and become more consistent. Then we will know where the real storm will hit. Further, you can get some idea of where it will hit from these forecasts. The runs seem to center around the New England and New York City area, so I think this area is the most likely to get hit. Further, it is not coming in at a usual angle in any of these runs, except those that take it to sea. It looks like it goes out to sea, then it bends to the west or northwest. This makes striking Delmarva, New Jersey, or New York more likely than usual. This is therefore a storm to watch. By the end of the week, we may know just who Isabel is going to visit.
posted by Jim on 9/8/2003 07:58:45 PM

Isabel Day 2: Deep Impact

Isabel is continuing to head north of west. Forecasters have been saying she should head due west, but so far it has not happened. She has reached 20 degrees north, and according to these forecasters, she should now turn west. We will see if she does so.

In the meantime, I have four more Isabel scenarios from GFS. The latest one takes it right into central Virginia, where it piles more rain than we ever need this year. Here is the Isabel summary, where the 0, 6, 12 and 18 are the hours of the runs in Universal Time:

2003 September 7
12 - New England
18 - sea

2003 September 8
0 - Maine
6 - S. Florida
12 - Nova Scotia
18 - Delmarva, Baltimore 2003 Sept 21 2 am EDT

2003 September 9
0 - sea, turning around on 2003 Sept 23 8 pm EDT
6 - Nova Scotia 2003 Sept 23 2 am EDT
12 - Myrtle Beach (another Floyd) 2003 Sept 23 8 pm EDT
18 - S. Florida, then heads up to Central Virginia 2003 September 23

That's the date it strikes Florida. It strikes Virginia a day later, and then heads towards New York City. This pattern of hitting some place on the East Coast has now come with about 75% of the runs. As Gary Gray says, "It remains way too early to say anything solid on that. Suffice it to say that the model trends and unanimity favor some sort of impact." You heard it folks. Deep Impact is coming. It's two weeks away. Where it will strike is anybody's guess - might as well play roulette. But it's likely to impact somewhere, so the entire East Coast should monitor this storm.
posted by Jim on 9/9/2003 08:23:51 PM

Isabel Report 3: Consistency Developing

Here are the runs since yesterday of GFS, showing where Isabel strikes:

0Z - Charleston, SC
6Z - hanging off the coast of central/southern Florida for 4 days, then head to Charleston, SC
12Z - grazes east coast of Florida, then hits NC and gets into Central Virginia, in one day
18Z - hits Miami, then turns north, scrapes the entire Florida coast, goes off the coast along the Carolinas and Virginia, giving them a deluge.

There is some agreement in these runs now. They aren't popping all over the place, Florida one hour, Nova Scotia the next, sea after that, and so forth. They are settling down on a path towards Florida, then coming up the Southeastern seaboard. So it seems that this is where Isabel is headed. The manner is still undecided; one run hangs it around Miami for 4 days, the others move it quickly. But they agree on Florida, Carolinas, and Virginia, and this is the area that needs to watch the most for Isabel. These areas need to keep abreast of the storm.

Further, I notice another storm coming. Unless some mess somewhere develops a wind and circulation, this will be called Juan. It is forming off the coast of Africa right now and will follow the path of Fabian and Isabel. However, it looks like this one will turn out to sea.

2003 September 10 2124. I just got Gary Gray's analysis. He is making a prediction. Yes, this is 10-12 days out, yet he is making a prediction. He agrees with me that the model runs are showing consistency from run to run and among the rather sparse set of models as well. He says the hurricane will move just north of the Bahamas, turn north, then northeast, then hit the Carolinas. He does not say that Florida will be hit, whereas I say it above. He mentions that the GFS has a solution that almost takes it into the Gulf of Mexico before a ridge catches it, pulls it up the Florida coast, then skirts it by the Carolinas. But other models call for it to be farther east, missing Florida. Apparently Isabel is headed our way; it's going to be like Floyd in 1999. I still say interests in Florida and the Carolinas should watch this storm carefully.
posted by Jim on 9/10/2003 04:58:52 PM

Where is it headed? Isabel report 4

This morning I got a jolt. For the past day or so, the GFS runs have been indicating that it would go by peninsular Florida, then head out to the northeast and hit the Carolinas, and Gary Gray came to that conclusion also. I looked at the GFS run this morning and found to my surprise that it was going to go to New Jersey instead! That would have meant hurricane force winds in New York City. The 12Z run took it to eastern Nova Scotia, and 18Z has it pounding the Canadian Maritimes and causing a major disaster there. So now what? Where is this thing going? It is starting to go east and pop all over the place again.

Tonight I took a look at Gary Gray's take on the storm. He says that the GFS tends to let go of ridges and troughs too soon, and in Isabel's case that would take it farther to the east. The maps indicate a huge high in the north Atlantic that blocks Isabel and makes it go west. He concentrated on other models, including one called ECMWF. So I took a look at that myself. It only goes 6 days and at that time, next Wednesday, it has it out in the middle of the Atlantic, but in a trajectory that would take it to New England. So it sort of agrees with GFS. Gary Gray winds up concluding that it is likely to hit either the Carolinas or New England. So both areas need to watch for this storm.

The other thing I notice about it is Wow!! It is up to 160 mph, making it a Category 5 hurricane. This has me concerned. Sustained 160 mph winds would really cause damage to an area. Even 140 mph winds would, if it should weaken a bit before hitting shore. So that has me concerned about hurricane force (75 mph) winds in my area, which would knock trees down everywhere and cause some roof damage. But it is not the most forceful tropical storm out there now. Typhoon Maemi had 175 mph winds gusting to 205 mph and is forecast to turn northeast and go between Korea and Japan; it is now down to 140 mph.
posted by Jim on 9/11/2003 09:35:16 PM

Isabel looks like Gloria: Report 5

Here are the past few runs' results:

September 12
0Z - Delmarva Peninsula
6Z - Skirting Delmarva, enter at New Jersey
12Z - Delmarva Peninsula, then towards Buffalo, NY
18Z - Delmarva, VA, then towards Buffalo, NY
September 13
0Z - New England
6Z - New Jersey and Long Island

Yesterday the runs were all alike, and they corresponded with other runs too. They imply a landfall somewhere in Eastern Virginia, which had me concerned. Isabel was going to come in at an unusual angle, headed northwest. Then this morning's runs come in saying that it is going to miss Virginia altogether and head to New England, and at 6Z, it came a little closer, heading to Long Island. The other models don't seem to go out far enough, and they are hard to find on the Internet. But I did find GEM, which is a Canadian model, and that one looked really interesting. Isabel would head to Norfolk, skim by Norfolk and Baltimore about 150 miles off shore, then make like it was going out to sea. Then it makes a subtle turn to the Northwest and scores a bulls-eye on New York City, on downtown Manhattan. Considering what happened two years ago, I think New York will be well prepared for this storm if that happens.

But where will it actually go? There is still some variance in the models. I looked at past history and found that Isabel is different from Fran, different from Hugo, different from Floyd. Hugo really concerned me. It hit Charlotte, NC with 85 mph winds, causing power outages to 95% of the city and covering some streets with downed trees, and this is as far inland as Richmond is.

I got a clue this morning from the track. It looks a lot like Gloria in 1985. The path is similar, going north of the Caribbean islands and then heading for the Outer Banks. Like Isabel, Gloria had high winds, up to 150 mph, and a really low pressure besides. As Gloria approached, the winds died down, as Isabel appears to be doing now. Further there was a weak tropical storm named Henri (this was 18 years ago and hurricanes repeat names every 6 years, and 6 divides 18 evenly) just like now that went up the coast before the big storm arrives. Like now, there was a front going across the mid part of the nation, from Wisconsin to eastern Texas.

So to determine where Isabel is going, look at how it differs from Gloria. Gloria's Henri, for instance, developed out of nowhere off South Carolina and then went up the coast in a straight line. 2003's Henri developed in the Gulf of Mexico instead, crossed Florida and petered apart a while in the Atlantic before moving west to hit the coast, then move northward. This does not tell much about where Isabel is going, but we need to look at differences between the storms to give us a clue.
posted by Jim on 9/13/2003 08:18:41 AM

Isabel Report 6: National Guard Shortage

I have seen all of the runs of GFS today and they all say pretty much the same thing: Isabel is going to just miss the Outer Banks, come ashore somewhere around Norfolk, ride up the Chesapeake to Baltimore, then head straight for Rochester, NY. The population potentially affected by hurricane force winds is huge: Washington, DC, Baltimore, Philadelphia, maybe even New York, and then the upstate New York State cities, especially Rochester.

It is apparently not losing its maximum wind speed much, now about 155 mph. The weather forecast seems to say it will be 120 mph at landfall - a Category 3 hurricane. I am not sure what this will mean to places on the periphery of its clouds; I can't find the maps that show predicted wind speeds out to whichever radius. But they are powerful. If they hit the Outer Banks that powerful, it may redraw the geography. It may destroy the Oregon Inlet Bridge, but it may also fill in the inlet, meaning that they would simply pave an at-ground road instead of building a bridge. But another inlet will open up elsewhere, requiring the bridge there, perhaps somewhere on Pea or Hatteras island. That was open before at Pea Island and there is an abandoned bridge there which crossed that inlet.

After the hurricane, rebuilding will need to take place, and usually the National Guard is called out to help. But when we call on the National Guard this time, there may be no Guard we can call on, or inadequate Guard, because these troops are all in Iraq. They may have to borrow from Guards in other states, even though they are short too. It seems to me that we didn't need to pile all those troops in Iraq - they are needed in the states at times.
posted by Jim on 9/14/2003 07:43:30 PM

Report 7: Isabel surprises

Just as it seems the models are in agreement and Isabel is headed right up the Chesapeake Bay straight towards the Washington Monument with 120 mph winds, Isabel pulls some surprises. They were talking about some shear affecting her progress. Today she got clobbered by it and her winds, despite an incredible tornado-like 236 mph gust in the clouds, dropped from 145 mph to 125 mph. Her huge eye, as if it suddenly looked into the bright sun, shrunk and shrunk until it vanished. She is predicted to hit another shear tomorrow and become even weaker, but she may grow stronger over the warm Atlantic, but then she may get weaker in coastal waters. It's a "good news, bad news" game. And now she has pulled another surprise tonight. The GFS, ETA, and all of the "SHIPS" runs now show Isabel hitting further south in North Carolina, like at Morehead City, then heading northwestward into western Virginia, Tennessee, and West Virginia. The Canadian GEM still shows her shooting up the Chesapeake but not as severe as before.

So what does it mean? Maybe Washington, Baltimore, and especially Hampton Roads are off the hook. It would be headed straight for Richmond, but go south of there and because of crossing over all that land, it weakens to tropical storm force with some hurricane winds over water. There would be no major catastrophic storm; as Gary Gray says, the Atlantic Coast won't fall off into the sea.

But keep alert, because more surprises may be coming. She may head to New England. She may hit South Carolina and produce floods there. She may even get into western Virginia, wheel around, and head back to Philadelphia and New York. Hurricanes are notoriously unpredictable and we should keep alert. Gov Warner was right in calling a state of emergency in Virginia. Hope he can deal with this emergency without the National Guard troops that can't help because they are in Iraq.
posted by Jim on 9/15/2003 07:11:59 PM

Isabel the Windy Storm

This is my last report on Isabel. It was hard to see from radar just where this storm was going. Its wobble first had it seemingly scraping the coast, then at another time, it seemed to be headed straight to Raleigh. But it followed pretty much what the models and NOAA had been saying about what the storm would do. Floyd in 1999 was a rainy and floody storm. Isabel was a windy storm - not too much rain fell.

I was afraid of the high winds that would come here. They were predicting 75 mph winds for Petersburg. They canceled my place of work for two days, so I was at home when it occurred. In the morning it was a gentle but steady breeze. It started to increase by lunchtime. It seemed like it was almost calm at ground level - our maple tree did not sway much, but the tall trees, about six stories high, swayed back and forth. In the afternoon, the wind got much fiercer, blowing twigs off the trees, but then it eased up about 3 pm to 5 pm. They started picking up after 5 pm, and we lost power at 1729 (5:29 pm). At that time the center of the storm was just crossing into Virginia. I did not get any more visual pictures after that; the TV station was broadcasting over radio, and I could hear what the weatherman was saying. At 1852 a roar occurred outside. When it arrived, the trees in our back yard started bowing way to the left at a 45 degree angle or more, and one tree bowed over straight. It was falling down! It landed harmlessly along our back yard boundary, although it missed our telephone box by about two feet. The storm continued from 7 pm to 10 pm, howling and producing more wild bendings of the tree. I heard that the TV station recorded a gust of 63 mph - on the boundary between whole gale force and storm force - now I know what a whole gale is like. Sure enough, it uproots trees. After 10 pm the winds died down considerably, and the rain ebbed to a mere drizzle. Hardly any rain, but the wind was still fast and howling. I went to bed and heard them and it seemed soothing in a way, like there was something going on out there and I was safe in bed - it was the same sort of feeling as when I get when I hear a train pass about two miles way.

The next morning, I went out at 7 pm. Guess what? There was a party going on in the street. The weather was beautiful. There was lots of clear sky and some altostratus clouds, and it was nice and cool. We went out in the neighborhood to see the damage. I found out that a tree had fallen on another tree near our house. On one corner of our house, about 10 feet away, there are three trees and I was afraid that a storm some day would blow them on our house and cause serious damage. So I wanted to get rid of them, but an association board member and a tree surgeon told me that they were sturdy trees - the house would go before them. So I never got around to having them chopped down. Good thing I didn't. One of those trees protected my house from being hit from the tree behind it in my neighbor's yard. If I had had those trees removed, the tree from the neighbor's yard would have damaged my house. I will probably leave them there, then; they are guardian angel trees. The neighborhood had lots of trees down, including an attractive willow. Two houses were damaged by a tree hitting a corner of their house.

Phone service went out with the power, and I figured I would have to wait a day or two for power. But surprise. It came on at 1519 yesterday (2003 September 19), and so did the phone service, but not cable TV. But still I seem to be in a favored class. 325,000 out of 425,000 customers of Virginia Power currently don�t have power. So cable TV (and high-speed Internet) seem to be small potatoes. It does indeed affect me still. The gasoline stations are closed because of lack of power, and those that are open have huge lines at them. This suggests what will happen when the Big Petroleum Shortage Rollover occurs, probably near the end of the decade, from what some geologists say. The banks are closed, and I am afraid to use ATMs for fear they will swallow my card. It was to be an active weekend, but Isabel wiped out four, or possibly six, events that I was maybe going to.

It was the worst storm ever to have hit the area that I lived in. It was worse than Fran and Floyd. Fran gave us a 2.5 hour power outage, and we never lost power during Floyd. The only storm that comes close was the Great Christmas Eve Ice Storm of 1998, which caused a 21-hour power outage at my house. The unusual thing about it is that 16 days before, on 2003 September 8 (it looked like it would hit on the 24th then) I knew that it could hit the East Coast. At that time I saw a virtual storm coming. Well, the virtual storm headed straight towards the real storm and came together right over my head.

Look at my weather page. I had not changed this in a while, but I am going to be converting this to a page on Isabel, including all the blogs that I have made to Blogtrek on this hurricane.
posted by Jim on 9/21/2003 09:42:45 AM

Predictable/Unpredictable

With situations of the kind that hurricanes posed, it seems that things are either in fine agreement or they are haywire all over the place. There is no middle ground. With Isabel, the first few runs were all over the place: sea, Florida, Baltimore, New England, Nova Scotia. But then after a few days they consistently pointed a finger at North Carolina and Virginia. There was no mildly unpredictable phase. It is either precise enough to predict accurately or you can say absolutely nothing about it.

Similar situations happen in mathematical systems. For example, in estimating a quantity, such as the length of the tropical year in solar days, 365.2422, the first three decimals are just about absolutely accurate. The fourth one is about right, the 2, but it is fuzzy and I have heard estimates that begin with 365.2421. After that the digits are totally unpredictable and depend on the irregular rotation of the earth. Another example would be to observe that if x is the square root of 2, then x = 1 + 1/(1+x) so if one guesses a value for x, substitute it into 1 + 1/(1+x) and make that your revised value of x, one may hope to obtain sqrt(2). If you set x = sqrt(2) you get sqrt(2) back, but if you are off by a little bit, say x = 1.414213562373, then the next few approximations are about this value but they lose a decimal place of accuracy each iteration. Still, it is good enough for practical purposes. When this gets back to the units digits, the whole thing becomes unpredictable. Try it out on a spreadsheet and you see what I mean.

Why does this happen? Both the hurricane and the iteration formula are unstable equilibria. If you are right on the money, you remain so, but if you are not, you eventually get thrown off the track. And that is what happened to the first few predictions for Isabel, 12 days ago.
posted by Jim on 9/15/2003 07:11:17 PM

Isabel and Dark Skies

Isabel caused a lot of power outages, damage to homes caused by trees, and other destruction. But when it left, it left behind a jewel. I went outside yesterday (2003 September 19) to see the stars, and I saw the darkest, most brilliantly star-studded sky that I have ever seen from my house. About 80-90% of the surrounding area did not have power. Therefore, the sky glow from light pollution was a lot less. I could easily see all the stars of the Little Dipper, and the Milky Way was visible from horizon to horizon. I went out with my telescope to try to see Mars, but I had trouble aligning my telescope, and I think part of it was that it was running on batteries. I did see it eventually and saw a dark stripe across the middle of the Red Planet. It was a real treat seeing a sky so dark from my house and I realize that this is something that occurs only about once every 50 years, when a hurricane as powerful as Isabel comes through here. I know that a teen-age woman named Jennifer Barlow has been trying to get people to turn off their outside lights in order to provide for a dark sky; in particular, declaring a Lights Out day. That was not too successful. It seems that Jennifer couldn't get people to turn off their lights. But Isabel could, and did. What is this society we belong to coming to anyway, when we need a hurricane to be able to see the night sky? I say make every day a Hurricane Isabel day. If you could not turn on an outside light during Isabel, then don't turn it on at all. I know some lights are needed for safety, but these may be far fewer than most people think. If everyone would do this, dark skies and knowledge about astronomy, especially among young people, would return.

posted by Jim on 9/21/2003 09:43:44 AM

Isabel and nautiluses

On 2003 September 17, Hurricane Isabel changed from its normal spiral galaxy-like shape to a spiral shape reminding me of a nautilus. It was interesting how the storm looked on radar when it was about 24 hours from landfall. The hurricane looked like a smaller copy of itself with a spiral tail coming from it. This means that the smaller copy looked like an even smaller copy of itself with a tail coming from it. A nautilus has a similar structure, and it is remarked that the ratio of the size of the nautilus to the smaller copy of itself is 1.618033989 or (sqrt(5)+1)/2, the golden ratio. However, Isabel's spiral did not fit that description. I used Paint Shop Pro to make an estimate of the sizes of the smaller copy of Isabel and its tail, and found the ratio to be somewhere between 1.29 and 1.35. This means that the tail is not in a square box, like it is for the nautilus. It is more of a rectangle, and one can build spirals with any kind of a winding ratio. I wonder if this ratio of about 1.32 is common among hurricanes or if anyone has studied it. I tried to estimate the rotation speed. I got first of all about one rotation every 12 hours and then a little while later, it was one every 6 hours. I tried to make a prediction of intensity levels based on this - it would get strong on Thursday afternoon, then weak later in the afternoon, then really strong at night in two separate bands. I was pretty much correct - I observed these things actually happening.

What caused the nautilus structure? I think that all spirals, including spiral galaxies and hurricanes, have this type of structure, although it may look like a disk. Most hurricanes and unbarred spiral galaxies have several spiral arms that make it look like a solid disk. Isabel caught a collection of cold, dry air in its western periphery, and this cold air got into it destroying some spiral arms. Only one was left, and this enables one to see the spiral structure easily. It looked like Isabel had several eyes at one point. In any case, it did not affect the predicted (which turned out to be actual) effects of Isabel, as one of the worst hurricanes of our lives.

posted by Jim on 9/21/2003 09:41:16 AM

Hurricane Isabel, 2003 September 17-19: the Windy One

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