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Tuesday, September 14, 2004 |
A HURRICANE WARNING IS IN EFFECT FROM GRAND ISLE LOUISIANA TOAt 10 PM CDT, the center of Hurricane Ivan was 295 miles south-southeast of the mouth of the Mississippi River and moving to the north-northwest at the faster rate of 12 mph. Maximum sustained winds remain at 140 mph and minimum central pressure has risen to 932 millibars (27.52"). Hurricane force winds extend outward up to 105 miles from the center and tropical storm force winds extend out up to 260 miles from the center. Some fluctuations in strength are expected during the next 24 hours, but the big picture is that a Ivan will be making landfall as a strong hurricane. For practical purposes, the track forecast is unchanged and the models are in appropriate agreement with each other. As with Charley, a very slight error in where the fateful turn occurs would have a significant affect on the outcome, but not so large of a one that it would get outside of the warning box. It is crucial that people in evacuation areas heed the orders. The worrisome aspect down the line is the forecast for it to stall in the mountains of Alabama/Georgia/Tennessee/North Carolina. That would set the stage for a truly epic rainfall/flood event. But one thing at a time... ...I pray that there isn't something that's being overlooked or misgauged and that the forecast for landfall east of New Orleans is right. I will breathe much easier when there are definitive signs of a recuravature away from Lousiana. Weather comment []11:25:55 PM  trackback []
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| Not for the sake of the forecasters, but for the sake of New Orleans. Wizbang explains the nightmare of a landfalling hurricane that puts New Orleans in the front right quadrant of the storm. It reminded me of something I had read years ago in my (1st edition) copy of Jack William's excellent The Weather Book. It has this as a sidebar note: Hurricane forecasters consider New
Orleans the USA's most dangerous area for strom surge, since a storm
could drive 20 feet of water into the city.
It has a graphic showing the output of FEMA's SLOSH model
that is used to estimate the potential for storm surge. The input
is a category four hurricane passing south of New Orleans, moving
west-northwest. The output is 18-21 feet of water along the east
banks of the Mississippi River and 15-18 feet in New Orleans.While the forecast is for this scenario to not play out, the margin of error is very small, so people should not take any chances. The advice from On the Third Hand is dead on. Weather comment []10:56:54 PM trackback []
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| At 8 PM EDT, the center of Hurricane Ivan was 325 miles south-southeast of the mouth of the Mississippi River. Forward motion is to the north-northwest at the increased rate of 10 mph. Maximum sustained winds remain 140 mph and minimum central pressure is 929 millibars. Hurricane force winds extend up to 105 miles from the center and tropical storm force winds extend up to 260 miles from the center. Up to this point, it looks like scenario one is playing out (see Notes and observations post below). Weather comment []7:58:54 PM trackback []
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AT 4 PM CDT...2100Z...A HURRICANE WARNING IS ISSUED FROM GRAND ISLEAt 4 PM CDT, the center of Hurricane Ivan was 370 miles southeast of the mouth of the Mississippi River and moving to the north-northwest at 9 mph. Maximum sustained winds remain 140 mph and minimum central pressure has fallen to 929 millibars. Hurricane force winds extend 105 miles from the center and tropical storm force winds extend 260 miles from the center. The eye has become better defined in recent hours. Ivan is about to move over an area of exceptionally warm water that could help it strengthen slightly. The expectation remains for Ivan to be a category three hurricane at landfall, due to cooler waters and some shear near the coast. Initial motion is set at 335 degrees, and in the past couple of hours has been almost due north. The forecast track is essentially unchanged (a very slight nudge to the right, I think) and is in the middle of the tightly clustered model guidance. Obviously, if you are in the warning areas, you need to be finalizing preparations and pay close attention to the progress of Ivan. Weather comment []5:08:19 PM trackback []
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| The drama of the oversea path of Frances is nearing an end. The first trough has lifted out and now there are only two players. One is Ivan the other is the second trough that is currently in the mountain states and pushing southeast. It is a bit of a race. If Ivan is quicker than the trough in nearing the coast, then landfall will be on the western half of the envelope. If the trough gets south quick enough, it will be able to turn Ivan to the northeast before landfall, putting landfall on the eastern half of the envelope. The models (and hitherto the National Hurricane Center forecast) are going with the first scenario. At this point in the game, it is very difficult to go against the models without a really strong argument. The second scenario currently appears to be more of an outside chance than likelihood. The UCAR satellite page offers good options for viewing satellite images of the United States. Water vapor offers a pretty good view of the situation. Warnings will probably come out with the 5 PM advisory. Based on extrapolation, I can't see a landfall any further west than Plaquemines, Louisiana (the sotheast part of the state that sticks out the most). Based on the potential for recurvature (northeast turn in this case) before landfall , I can't see landfall any further east than Appalachicola/Panama City. Of course, hurricane force winds extend out about 100 miles from the center, so the windfields associated with that swath I've described are a bit larger. ---------------------------------------------------------------------------------------------------- Looking at the satellite images of Ivan in the past three hours or so outflow to the southwest has clearly improved. ---------------------------------------------------------------------------------------------------- The favored activity of FSU students at the moment is to speculate on the possibility of school being cancelled. To that end, the alerts page is being monitored closely. Due to evacuations in Bay County, the Panama City branch has been closed indefinitely. Right now, classes are on as scheduled, with the next update in status coming at 6:00. With Frances, it seems like it was more of a matter of the state telling the University to shut down, rather than the school coming to the decision on its own. One would expect a similar situation to play out this time. The students, however, being highly safety concious, are pushing for closure for the balance of the week. Regardless, if landfall continues to be forecast west of say Mobile, it is unlikely that school will be closed for any period of time. Weather comment []4:47:37 PM trackback []
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| At 10 AM CDT, the center of Hurricane Ivan was 435 miles south-southeast of the mouth of the Mississippi River and heading north-northwest at 8 mph. Maximum sustained winds are down to 140 mph with hurricane force winds extending up to 100 miles from the center. Minimum central pressure has shot up to 932 millibars (27.52"). It appears that hurricane warnings will start going up this afternoon. A hurricane watch currently extends from Morgan City Louisiana to St Marks Florida Even with its reduced strength estimate, the advisory could still have Ivan a touch too strong. Nevertheless, it is still expected that Ivan will be at least a category three hurricane at landfall. The heading of the storm is set at 330 degrees. Forecast track shifted to the left slightly and corresponds most closely to the FSU superensemble. Also at this hour, the NHC bestowed a named upon tropical depression eleven, making Jeanne the tenth named storm of the season. People in south-eastern Louisiana, the coastal areas of Mississipi and Alabama, and western-most Florida should be finalizing their preparations without delay. PaperFrog in Pensacola gave us a view of what's going on there and will have evacuated to higher ground by Wednesday morning. Weather comment []11:14:23 AM trackback []
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| At 8 AM EDT, Hurricane Ivan was 450 miles south-southeast of the mouth of the Mississippi River and moving to the north-northwest at 9 mph. Winds have decreased slightly to 155 mph and minimum central pressure is up to 925 millibars (27.31") Hurricane force winds extend 100 miles out from the center and tropcial storm force winds extend up to 225 miles out. Weather comment []9:31:12 AM trackback []
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| Ivan related news from Gulf coast newspapers this morning... We're still not out of the woods (Tallahassee Democrat) Ivan inches closer (Pensacola News Journal) Evacuatation begins (Pensacola) Military bases brace for hit, prepare to assist at shelters (Pensacola) Casinos wonder if Ivan that dreaded storm (Biloxi/Gulfport Sun Herald) Boats headed for safety (Biloxi/Gulfport) [From the Times-Picayune] (New Orleans) Stores struggle to meet swift surge of demand (New Orleans) Eyes on Ivan (New Orleans) La. Utility workers doing about face (New Orleans) Oil workers evacuated from Gulf (New Orleans) Weather comment []5:27:23 AM trackback []
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| At 5 AM EDT, Hurricane Ivan was 85 miles northwest of the western tip of Cuba and 575 miles south-southeast of the northerrn Gulf coast, moving to the northwest at 9 mph. Maximum sustained winds remain 160 mph and minimum central pressure is 924 millibars (27.29") A hurricane watch remains in effect from Morgan City Louisiana to St Marks Florida. Ivan could actually be slightly weaker than the advisory states. Forward motion remains set at 320 degrees. The track forecast and the reasoning behind it is essentially unchanged. The dearth of new satellite images only just ended, so it will be a couple of hours before a useful loop is reestablished. Kind of hard for me to make any intelligent comments without them. Weather comment []5:08:50 AM trackback []
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| At 2 AM EDT, Hurricane Ivan was 55 miles northwest of the western tip of Cuba and moving to the northwest at 9 mph. Maximum sustained winds remain 160 mph and estimated minimum central pressure is 922 millibars (27.23") Sigh. No new satellite images in the past two hours...it's naptime now. Weather comment []4:51:33 AM trackback []
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| At 11 PM EDT, Hurricane Ivan was 40 miles west-northwest of the western tip of Cuba and moving to the northwest at 9 mph. Maximum sustained winds remain 160 mph and minimum central pressure is 914 mb (26.99"). A hurricane watch is posted from east of Morgan City Louisiana to St Marks Florida. Heading is set at 325 degrees. The forecast track was again shifted to the west and is just east of the FSU superensemble track. Just got back home after spending some time doing synoptic meteorology and atmospheric dynamics homework with a classmate. We both disagreed with the forecaster's description of the motion being northwestward with a north-northwestward wobble; we see it as the opposite. Looking at the forecast models so far: In its latest (00Z) run, the GFS shifted a little to the east from its run 6 hours earlier. NOGAPS is essentially unchanged and is left of the GFS. The Canadian model shifted east and is east of the GFS and NHC forecast. According to the discussion, the NHC track is near the GFDL track, which would seem to make it unchanged. It's going to be interesting to watch... people in the watch areas need to be getting ready for and paying close attention to Ivan. Keep in mind that hurricane force winds are extending outwards 100 miles from the center and tropical storm force winds are extending out 200 miles. Weather comment []12:54:47 AM trackback []
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© Copyright
2004
Charles Fenwick
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Last update: 10/2/2004; 11:03:35 PM .
Last update: 10/2/2004; 11:03:35 PM .
