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Saturday, August 18, 2012

This will wake you up

GFS has major hurricane (Isaac?) off Long Island on the first of Sept! Shades of last year!


Euro and GFS have a ridge in the Atlantic that is too strong for a system to hit directly from the Atlantic. Instead, they take Isaac into the Caribbean and around the ridge up into Florida or the Eastern Gulf. From there its possible to get up the seaboard. Keeping an eye out still. It hasn't developed yet and the stronger it gets the more likely it will head more north. Staying weak will push it further west.

8-21 update morning

The euro keeps it weak and passes over Jamaica befo it tightens up and hits the central gulf coast. GFS is just north of Jamaica, passes over Cuba, hits near the Keys, then again near S Carolina. These are the furthest south and west tracks. Gfs ensembles all take it up the east coast. Euro ensembles all through the Carribean. The hurricane models mostly take it near to the north or over Hispaniola, then up the East Coast. Cmc and ukmet are also tonthe right of the gfs. Right now the storm is starting to gain a Central dense overcast in the center, but remains a fast mover and subject to moderate shear. Once it slows down more, it should develop more. The earlier it does that, the further north it goes.


Isaac still hasn't wrapped itself up, despite its core staying away from land. Its weakness resulting in a further west movement. Also, the trough coming through the US, which seems so strong, has stalled in the southern half of the country. So, the Euro, per above, was correct so far in the end game. Todays run of the Euro is scary for NOLA. The storm intensifies as it nears, and stalls just to the east of Lake Pontchartrain, keeping northerly winds of at least 40mph driving water toward the city for about 48 hrs. The rains first arrive in NO at 12z Tuesday the 28th and continue until 6z on Friday. This would be extreme. Wind wise, just to the east of NO is hit rather hard with 36 hrs or longer of hurricane strength winds. Problem with the Euro model is that the wind chart maxes as 75kts and the rain chart maxes at 5inches. Both of these will be exceeded.
CMC follows the Euro, but not as strong
UKMET follows CMC- like Euro but weaker
NAM follows CMC, but doesnt go stronger than 996 and winds don't go above 45kts at the surface. Flight level winds never above 55kts.

GFS runs so far today track it southwest of NO, just over the delta. IT too slows the storm down as it reaches the coast. This puts NO in the windier section and storm surge from the gulf, which I trust more than a surge from LP (as in Katrina). GFS doesn't strengthen Isaac to a hurricane though.

HWRF takes it to 100kts, just to west of NOLA
GFDL takes it into E Texas, with 66kt being the top wind

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