ICAP Weather Commentary
Thursday August 28, 2008
Prepared by: Andy Weingarten, Meteorologist ICAP Energy
***Gustav intensifies, Hannah is forming and autumn is arriving in the west.***
We will have two named storms in the Atlantic basin by later this morning. Gustav is intensifying quickly now that it is away from Haiti. Winds were back to 70 MPH and should be a hurricane soon. The movement overnight was a little south of west which was a little unexpected. It is possible the center passes on the south coast of Jamaica today rather than the north. Some interaction with land may weaken this again later today and tonight. Once past Jamaica, we should be off to the races tomorrow and Saturday with intensification in an ideal environment. The model and hurricane center tracks have shifted west overnight, presumably in response to the SW move.. I think they will continue to edge west today and tomorrow and Texas is still very much in play. The depth of a turn to a more northerly component will be impacted by two things, strength of the storm itself and strength of the trough that forms to the west. The models all seem to agree the trough strength will be pretty strong which shifts the ridge east and allows for a turn. I am fine with that, however if we are a strong storm (Cat3-4) as predicted a wider more sweeping turn and not as sharp a NNW component as shown is possible. Most of the models are still a Louisiana storm, but many have gone land point west of New Orleans now. A couple of the global charts (NOGAPS and UKMET) are showing the upper Texas coast. Until strength of storm and trough are determined I am not confident yet this still doesn’t go west of Houston. TD 8 will become Hannah later today. Its northern position in the Atlantic would make it unusual to come back SW into the Gulf so at this point I don’t see a real threat. But, a couple of forecast charts have enough of a WSW movement next week to make it close. It could at the least be a Florida hurricane threat.
The trough discussed above that tries to turn Gustav north or NW this weekend will put an end to the current hot spell in the interior west. A brisk cold front should go through even the southern areas and head east early next week into the Plains. Some rain is likely with this over the NW. Another front in the Plains will head SE this weekend, but the cooling behind it is minimal. The air should dry out a little, but temperatures over much of the country between the Rockies and Appalachians are still above normal. But, other than ERCOT which is in the 90's, it is almost exclusively 80's which is not much of a heat concern this time of year. the east coast is a little cool the next couple of days in the wake of Fay's remnants, but should moderate to at least normal for the holiday weekend.
Day 6-10 discussion:
The pattern should feature a trough in the west and a ridge over the Lakes and NE. There are some differences within the models on how far east this low comes. The GFS is much broader with it so it has a more widespread cooler area that comes well east into the Plains. I think there is enough amplitude in the pattern to where that is overdone. On the flip side, the European may be too widespread warm. So, a compromise seems in order right now and I went below normal NW and above Lakes and NE. Either Gustav or Hannah could have impacts in the south and there could be pockets of rain cooled air. Steering currents are supposed to weaken so figuring out where they would go longer range is a tough obstacle. The same issue occurred with Fay and near normal seemed to work for most areas so that's what I will put out for now.
Andy Weingarten, Meteorologist
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