Wednesday, September 30, 2015

Late Week Flooding/ Hurricane Joaquin Update:

Joaquin became a hurricane earlier today and continues to slowly drift southwest towards the Bahamas. In the meantime, a cold front has pushed through and stalled along the east coast. The forecasting challenge over the next few days remains how and to what degree these features will interact with each other this weekend.
The majority of weather guidance (including the GFS, GFS ENSEMBLE MEAN, UKMET, CMC, and most of the tropical models) want to take Hurricane Joaquin up the eastern seaboard before making landfall along the mid-Atlantic coast---somewhere between the Carolinas and Delmarva. On the other hand, the EURO (a model well known for its accuracy) steers Hurricane Joaquin northeast and out to sea. It'll really all come down to how much interaction there is between Hurricane Joaquin and the trough over the east... basically whether it can suck the storm in or not. I think both solutions are plausible and make sense meteorologically. Minuscule changes in the mid and upper levels will make all the difference so I don't feel comfortable locking in on a solution just yet.
With that said, a big take away is that regardless of what happens with Joaquin, we'll still see plenty of deep, tropical moisture brought in and dumped along the front as it builds westward---starting across Hampton Roads tonight and eventually working its way through the rest of the state tomorrow night into Friday. Since the ground is very saturated, flooding is expected. A persistent onshore flow will also lead to coastal flooding/erosion beginning tomorrow night and lasting through the weekend. A land-falling Hurricane Joaquin would just exasperate things with additional heavy rainfall and strong, gusty winds over the second half of the weekend.
If you live along the coast or in any sort of flood plane, have your evacuation route/plans in order. This is going to be a high impact event in Virginia---just to what extent is to be determined.

Update:
Some interesting data here.... the black line represents the recorded track of Hurricane Joaquin....the red line is the euro predicted path from 12z while the green is the gfs predicted path from 12z. Euro clearly doing better so far---not sure how or if this will correlate down the road...but offers a bit more credence to the European model.

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