Tropical Storm Debby

Update--   Below is my current (6/26  1500 GMT ) wind forecast for Debby. 

Clearly the (6/24 2100 GMT)  prediction further down did not pan out so well. Anyone who's ever made a less than stellar forecast would prefer the evidence of it to just fade away, but this deserves a word. 

FACT: The 100+ year hurricane catalog says that ON AVERAGE storms over Debby's part of the Gulf of Mexico  should strenthen with time and accelerate toward the north or northeast.

By slowly losing strength and drifting east at a snail's pace, Debby bucked the average.

If you are a gambler, bucking the average is not unheard of, but it does point out the need to convey forecasts of all types in terms of probabililty. Probability versus  yes or no - it will or it won't. Properly stated probablisiic forecasts can be quantitatively evaluated given enough occurrences, whereas the latter type can't.

Still, everyone would like to be spot-on in prediction, even if they said there was only a 45% chance.

At 6/24/2012  21 GMT  Tropical Storm Debby is about 170 km from the Florida Coast.

Below is wind exceedence forecast at 25%  probability based on current storm position, strength and velocity together with information from the historical hurricane catalog.

Second below is the 5 day wind forecast for Apalacicola FLA. The forecast for there gives 45% chance for winds exceeding 50 kts and 80% chance for winds exceeding 40 kts.

Steven N. Ward   Santa Cruz