Sunday, September 4, 2011

Update on Katia and Lee.

Good morning everyone..This is just a quick update on the tropical systems.. hope everyone has a great Sunday. Katia dropped to a Tropical Storm Again overnight. However once again she as bounced back to a hurricane.  The reason for this up and down, the dry air I talked about in the last blog on the tropical systems. I have noticed that winds might be understated in katia. same buoy reports winds sustained 71.9KTS gusting to 89.4KTS - that equates approximately to 80MPH gusting to 105MPH. This is one of those uncommon instances where the Dvorak T-numbers ( estimates of tropical cyclone intensity based only on satellite images)  understated the wind speeds. The only reason I mention this is because of the media  attention about winds in Irene being overstated and here is an instance where in the absence of a recon flight providing real time data from the center there will be times where the strength is stronger than what it appears. The models keep bringing Katia westward. But like I said in the last blog, Katia would come close enough to scare the east coast. It's still too early to talk about east coast landfall.....But, I still feel Katia will not make a landfall. There are two reasons I feel this way. One is the Trough that should be in-place enough to force Katia to recurve back out to sea. The second is a upper level low (ULL) in the Tennessee Valley. If Lee get involved with this ULL and hangs out long enough in the Tenn. Valley then he will serve to help steer Katia along the coast. If Lee isn't effected by the ULL then Lee would move toward the NEUS a little quicker. Once Lee was in the NE he would help push Katia away from the coast. Either way, Lee is a contributing factor to the eventual path of Katia. It's all intertwined. I'm beginning to think Katia will not reach Major hurricane status. This is impotent because as a Cat 3 she could have pushed back on the trough. moving closer to the east coast.

Tropical Storm Lee is still just off the coast of LA with winds down a little. Some of the moisture associated with Lee will be pulled up into NYS on Monday, The moisture will interact with a slow moving cold front.  This will enhance the rainfall With some areas seeing fairly substantial rainfall. There is uncertainty as to just where the heavier bands will set-up....I think the heavier rain will be just west of the Capital Distract (but this is in no-way certain).  At this time it looks like Lee will track up over the  Appalachians or just west of them.  Lee could be approaching the Area on Thursday. As for how much rain he drops, it would depend on how fast he dissipates over land.

 This is an image of the upper air patterns. You can plainly see the steering patterns for both tropical systems. 

                                   Spaghetti  tracks of both systems.

QPF outlook


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