Each day in August, I'll update this first post with the forecast, both long and short term. As a general rule, up to 7 days is a pretty accurate forecast, beyond that it's educated guessing and largely dependent upon how well the models are doing at that moment. If you have any specific weather questions or comments, even if it's for an area other than WDW, please post and I'll answer throughout the thread. I'll also post weather tidbits every so often. Without further delay, let's get to the forecast:
Weather at WDW - Updated Sunday pm, August 31, 2008 :mickey:
So, as of Sunday afternoon we're up to about 4,200 views of this thread for the month of August. That has to be some sort of Intercot record. You'd think you folks were interested in the weather. :D
The outer feeder bands from Gutav will sweep across FL today and some tomorrow, mostly in the morning, bringing periods of heavy rain and a high of 88 each day. Neither day will be a rain out, but when it does rain will be tropical type rains so be ready. Tuesday through Friday WDW will be caught in sinking air from all sides with the remnants of Gustav to the west and Hannah to the east. Current models take Hannah past FL's east coast, but the west side of the storm is the "dry" side and right now it looks like through Friday WDW will have highs 91-93 with only very isolated afternoon thunderstorms. It will be VERY humid. Next Saturday and Sunday a little disturbance kicks up and there will be scattered thunderstorms with highs 90-92.
Now for voodooland...As always, tropical systems can disrupt the long term forecast, but for now September 8-11 looks like highs 90-92 with scattered afternoon thunderstorms. A front moves in on the evening of the 11th which really won't kick off many more thunderstorms, but the humidity will be lower for the 12th and highs Sept 12-16 should be upper 80s with only isolated afternoon thunderstorms. The models are keeping the tropics quite active, though, so that will need to be watched.
Travel Impact :plane: :truck: :drive:
At 12:00 pm CDT, Lake Charles, New Orleans, and Mobile are all closed due to Gustav. Expect a LOT of delays across LA, east TX, AR, MS, and maybe even AL today, tomorrow, and Tuesday. Some delays could occur across FL tomorrow due to high winds, but shouldn't be too major.
Tropics :fan:
***UPDATED 9:15 pm CDT***
No change on the Gustav information. Tornado warnings are starting to break out and pressure is dropping, though latest winds were still at 115 mph (Cat 3). There's some change in the Hannah info below.
Gustav weakened substantially overnight in the face of strong southerly wind shear and interaction with the terrain of Cuba. The eye became ragged and convection decreased. Winds dropped to 115 mph at early afternoon. Winds are expected to increase back to 130 mph, keeping it a Category Three hurricane. Slightly cooler water, continued wind shear and dry ir entrainment are working against any further intensity increase.
With the faster motion, Gustav will make landfall during the late morning hours on Labor Day. However, faster motion also means increased storm surge. That landfall will likely come over southern Terrebonne Parish.
Tornadoes will be a problem, especially within about a 200 mile radius of the center. Once inland, the GFS stalls Gustav over West Louisiana; this could set up a very dangerous flooding threat for Louisiana, the southern part of Arkansas, and the western half of Mississippi this week. If the stall happens, some spots could see 15 to 20 inches of rain in the corridor from Jackson to Shreveport.
Let's talk about coastal impact:
LA COAST - increasing showers, winds rising to over 25 mph this afternoon into tonight. Showers already showing up off Louisiana coast. Tropical storm force winds arrive after midnight, strong tropical storm force winds by daybreak, overspreading the area. Hurricane force winds reach coast by midmorning tomorrow. Sustained hurricane force winds in New Orleans from late morning though late afternoon. Winds push water into Lake Ponchartrain through the morning and into the south shore. As hurricane passes, winds shift and shove water against north shore. Worst case, trajectories midmorning blow water into eastern New Orleans. Of particular concern will be the area in eastern St. Bernard and and where St. Bernanrd meets Plaqueemines and west of Lake Borgne, where Orleans and St. Bernard meet. 14-15 feet of surge could happen here. Slidell will have an easterly fetch for a long, long period of time, which will cause serious tidal flooding, even though winds will likely not reach hurricane force.
MS/AL/FL
Increasing surf and riptides. Easterly winds gusting to over 25 mph starting this afternoon. Tropical storm force winds arrive after midnight. Winds stay above tropical storm force until midafternoon when winds will shift to southeast, allowing water to levels to rise. Tides will rise to 6-8 feet in places.
MORE ON STORM SURGE
Louisianans remember Betsy, which follwed a similar track in 1965. Betsy was about the same intensity as Gustav now. But Gustav is expected to intensify. Faster storm helps with storm surge. This may be critical. Official forecast calls for 18-25 foot storm surge in locations east of the center track. Some notes: A worst case on the Mississippi Coast would be around 17 feet, but I don’t think that is going to happen with the predicted wind trajectories on the current track. Same for Lake Ponchartrain, especially after storm passes to west. In Lake Maurepas, 14-15 feet. Prior to the passing of the eye, the south shore of Lake Ponchartrain may see 13-14 feet, which is more than Katrina. Water will pour into the West Back from the south. Surge heights in that area could be 10-12 feet. The rule is that one mile of wetland can knock down one foto of surge. In St. Charles, water will likely reach US-90, which is well inland.
Now, about Hannah. Those of you heading to WDW I know are concerned about this one. Things are basically the same this evening. Peak winds are remaining at 45 mph with shear preventing development, but that will change. The latest NHC track at 8 pm EDT still has Hannah as hurricane making landfall around Savannah, GA Friday afternoon. As WDW would be on the western side it shouldn't deal with any rain impact, though the heat would be higher as a result. The models continued to diverge tonight on Hannah, which concerns me more than it did this afternoon. The UK has stayed with it's original idea of taking Hannah south towards Cuba, over the FL Keys and into FL around Tampa. The NOGAPS, which earlier was taking Hannah into GA has now switched back to the idea of a Daytona landfall on Thursday. Those two remain outliers from the other models which still take Hannah up into SC/NC depending on the model, but as I mentioned with both Fay and Gustav, we have to watch these outliers because sometimes that particular model picks up on something before the other models do. And sometimes it's just off its rocker. The fact that the NOGAPS has readjusted south says something may be going on, but that's not for sure. The GFS, GFDL, and HWRF all bring it into the Carolinas late Friday or Saturday. Right now I'd say it's a 60-40 chance that WDW won't be impacted, but let's see what the morning models have to say and what features are popping up that will impact this storm's movement.
Invest 97 is going to struggle to develop for the next 2-3 days as it moves throuh unfavorable conditions and it may or may not grow into anything more. Right now the models bring it towards the Bahamas late this week, but we'll have to see if it hangs together to become anything. Invest 98, not far behind, will most likely become a tropical depression. It will probably become Ike pretty soon. Or maybe Josephine depending on what 97 does. However, right now the models are curving 98 out to sea with no threat to the US coast.
