Thursday, August 27, 2009

Hurricane Season

Well, here comes Danny. Just in time to make my Friday afternoon flight from Connecticut to Maryland interesting. As of this writing NOAA's Hurricane Center is forecasting this predicted track for the storm:

And that translates into a forecast map for 0000Z Saturday (i.e., about my ETA at VKX) from NCEP that looks like this:

Looking at the raw Model Output Statistics, the NAM forecast for 00Z at Andrews AFB (KADW) -- about four miles from VKX -- suggests that I should expect a ceiling of 500 to 900 feet and 2 to 3 miles visibility with wind out of the southeast at about 5 knots and a precipitation probability around 60%. That forecast, converted into a synthetic radar reflectivity graphic, looks like this:

The other commonly used model, the GFS, is, as usual, more optimistic. It calls for ceiling between 3000 and 6500 feet and visibility more than 6 miles. That model doesn't really have the ceiling and vis coming down until about 09Z.

So, if the GFS forecast verifies there's no problem. If the NAM forecast verifies then N631S and I will be once again enjoying the RNAV 6 approach at VKX (which has a minimum descent altitude of 680 feet MSL). If the low end of the NAM model shows up then it will probably be off to the alternate, which will be the ILS at Manassas (KHEF), and a rented car for the drive home.

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