Friday, September 24, 2004

Hurricane Jeanne Update 242300L At 11 PM EDT, the center of Hurricane Jeanne was estimated to be 315 miles east of Florida's southeast coast.  Jeanne is moving to the west at 12 miles per hour and maximum sustained winds of 100 mph.  Minimum central pressure is 964 millibars. Hurricane Jeanne Advisory Number 46 Intensity is held the same as the NHC waits for new observations from the Hurricane Hunter.  The forecast track  has shifted inland a little bit.  (Slightly better view of the forecast track).  Expectations still are for Jeanne to make landfall as a category three. Hurricane Jeanne Discussion Number 46 In focusing on the track forecast in my previous post, I neglected to mention the issues regarding Jeanne's intensity.  While Sea Surface Temperatures and upper level winds seem to be favorable for strengthening, Jeanne's structure will impede her.  Frances' large eye kept her from doing any kind of rapid intensification in the final day before landfall and Jeanne is similarly hindered.  Weather comment []11:17:24 PM   trackback []

Hurricane Jeanne Update 241700L AT 5 PM EDT...2100Z...THE HURRICANE WATCH IS UPGRADED TO A HURRICANE WARNING ALONG THE FLORIDA EAST COAST FROM FLORIDA CITY NORTHWARD TO ST. AUGUSTINE...INCLUDING LAKE OKEECHOBEE. A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED IN THE WARNING AREA WITHIN THE NEXT 24 HOURS. AT 5 PM EDT...A HURRICANE WATCH HAS BEEN ISSUED FOR THE NORTHEAST FLORIDA AND GEORGIA COASTS FROM NORTH OF ST. AUGUSTINE NORTHWARD TO ALTAMAHA SOUND GEORGIA. A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE IN THE WATCH AREA IN THE NEXT 36 HOURS. At 5 PM EDT, the center of Hurricane Jeanne was 400 miles east of southeast of the Florida coast and moving to west at 12 mph. Maixmum sustained winds are 100 mph and hurricane force winds extend 45 miles from the center. Minimum central pressure is 965 millibars (28.50") Hurricane Jeanne Advisory Number 45 Satellite imagery is starting to show signs that Jeanne is strenthening. Based on the minimum central pressure, the winds might actually be a fair bit stronger than reported in the advisory. Heading is set at 275 degrees but the motion might actually be due west at this moment. The models have a good bit of divergence in the timing (and therefore position) of Jeanne's turn to the northwest and north. Jeanne is forecast to make category three (115 mph winds) before landfall. Hurricane Jeanne Discussion Number 45 Obviously it is get ready ASAP time for the east coast of Florida. The one bit of good news is that the wind field is significantly smaller that Ivan and Frances (and just a bit larger than Charley's IIRC). The worrisome aspect is how much debris from previous storms is still laying around. The Florida-Times Union (in Jacksonville) had a front page story a day or two ago detailing how only 50% of the debris from Frances had been picked up (and keep in mind that Jacksonville was a good bit away from the center of the storm). All of that debris has the potential to become damging projectiles when Jeanne passes over. Once again my synoptic meteorology professor had an interesting storm discussion. He is becoming exasperated with history repeating itself with regards to certain models (GFS for one) that have consistently mishandled the strength of high pressure ridges. Readers of this blog during Frances will remember that the GFS model was the worst in weakening the ridge to the north (for a while the model was forecasting that Frances would turn to the north and run up the east coast towards North Carolina and at one point the NHC was taking the model into account for their forecast track which had Frances making landfall in Jacksonville). A very similar situation is ocurring with this storm. Their is a high pressure center just off the coast of North Carolina. For the past day or so, the GFS model has had the center too weak and not in the correct position. The result of the GFS' placement of the ridge is that it has Jeanne turning to sea before making a true landfall. Since the GFDL uses the same initialization as the GFS, it is plagued with the same issues. One thing that worries him is that even the UKMET model, which has handled the ridge better than the GFS, was already a little bit off in its handling of the ridge six hours into its forecast (i.e. at 2 PM today). (Summary of model's forecast tracks for Jeanne ) For the reasons stated above, the GFS and GFDL are almost certainly wrong. The UKMET track is reasonable, and while NOGAPS is an outlier, it does have some credibility. Because of this, people in central Florida should be making some preparations as well and keeping an eye on Jeanne's progress. The water vapor loop offers a good view of the action. If you look just to the east of North Carolina. you can see the clock-wise circulation of the high pressure. This is forcing Jeanne to move to the west. The only thing that keeps a near exact repeat of Frances' track from occurring is the front that extends from Michigan to Louisiana and is moving to the east. This will force the high pressure center to the east, which would cause Jeanne to turn northwest and north around the peripehery of the center and then northeast along the front. As always, the $64 question is the timing and extent of these events... stay tuned... Weather comment []6:03:04 PM   trackback []

Reporting for Duty! /me gives a John Kerry patented Land-Ahoy! salute that a drill sergeant would chew out a recruit for rendering. It's been an insanely busy week of meteorology homework.  I had quite a daunting test in Atmospheric Dynamics today, which I was well prepared for. My schedule is now clear for hurricane watching... Jackpotzrebie, Weather comment []5:30:55 PM   trackback []