| weathernet |
| (Storm Tracker) |
| Tue Jun 03 2008 01:46 PM |
Increased S. Florida Hurricane Risk? - May Precip. Totals
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Well, May 2008 is now "in the books". Could South Florida be in the crosshairs of a Hurricane landfall this year?
Now that May has passed and preliminary data for May rainfall shows how little rain we received here in S. Florida, I thought to re-visit a previously discussed observation ( and discussion thread ). According to Jim Lushine of NWS Miami, a study of his, has revealed a potential link between rainfall in May and probability of hurricane activity for South Florida:
Exerpt:
"Plotting 75 years worth of May rainfall data, Lushine found the probability of a hurricane striking South Florida ALMOST TRIPLED after a very DRY May. Conversely, the chances of a hurricane striking South Florida after a wet May were three times less."
NWS data for May 2008
Miami, Fl. - 3.81" below normal
Ft. Laud. Fl - 4.00" below normal
W. Palm Beach, Fl - 2.97" below normal
Naples, Fl. - 3.87" below normal
Tampa, Fl. - 2.12" below normal
For those seeking further information: http://www.insurancejournal.com/news/so ... /54367.htm
| craigm |
| (Storm Tracker) |
| Tue Jun 03 2008 03:58 PM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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Hey WN, Your link is broken - here is another one that works from my original post. Fascinating stuff. I was skeptical at first till I saw that he used 75 years worth of data.
http://www.insurancejournal.com/news/southeast/2005/04/28/54367.htm?print=1
| MichaelA |
| (Weather Analyst) |
| Tue Jun 03 2008 05:15 PM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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I wonder if that would also apply to West Central FL. May was bone dry here. It was -2.12 inches for Tampa (2.85 is normal). Heh-heh, I see that is indeed listed.
| weathernet |
| (Storm Tracker) |
| Tue Jun 03 2008 09:58 PM |
Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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Craig -
Hey thanks for "picking up" on the bad link; after you had mentioned that, I did realize that it did look a little short there.
I had heard that Jim Lushine had retired, but then again, he may still be there at the NWS office adjacent to NHC for one more year. Not sure. I had met him couple of times and spoken to him multiple others. Is a real nice and low key guy. I would be interested to see if he did research to further determine even additional correlation with dry and below normal rainfall totals for June as well. Just curious if the data changes or stacks up even worse. Not to say S. Fla. will continue on this "dry heave", but for now......., the pattern isn' t looking too wet for the first week of June. As for whether this data bodes threatening for only Southernmost Florida, I doubt it. My guess is that this is merely natures balancing act of evening itself out. Who can tell if, or exactly what areas might be affected in Florida by a tropical cyclone this year, but remember that it only takes one really good sucker to come north out of the W. Carib. to dump an awful lot of rain that could easily affect over 1/2 the state. Furthermore, add a pinch of "slow motion" when steering currents start to break down, say in middle to late Sept., and even an Arthur type storm would fill up some lakes and green up our lawns.
| AprilDriesse |
| (Registered User) |
| Wed Jun 04 2008 12:30 AM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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It also has been bone dry here in Lee County, but because were now entering rainy season, we get thunderstorms everyday. I think this year will have Florida in its tracks, just because it is so very warm early on in the year.
| Lamar-Plant City |
| (Storm Tracker) |
| Wed Jun 04 2008 06:36 PM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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I can't help thinking that one obvious possible reason for this relationship might be that when May is extremely dry, that means there has been little cloud cover in the the coastal areas and this might allow much more heat energy to build up (I.E. water temperatures). I know the GOM has been warming rapidly in May after stalling a bit due to a wet February and early March. Wonder if any cross correlations have been done with rainfall, water temps and hurricanes. I know there are a zillion other factors involved, but it has been sweltering under those clear blue skies this month.
What do our FLH experts think?
| craigm |
| (Storm Tracker) |
| Thu Jun 05 2008 01:32 AM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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Lamar, you bring up an interesting point about sst's being elevated under extended periods of high pressure influence and also that there are many variables. I think higher surface temperatures help explain intensification but not track. A storm won't track towards warmer water so much as being influenced by areas of pressure differential. I think dry Mays, in Florida or anywhere is a function of strong high pressure. In our case in Florida the ridge of high pressure that camps out in the middle of the Atlantic is very fluid and the western periphery dictates where and when storms turn Northward. Due to the coriolis effect storms are always trying to turn poleward. High pressure blocks this turn. Try and picture the atmosphere in 3D. High pressure areas are like mountains only inverted and low pressure areas are like valleys inverted, this is what allows cloud heights to build - lack of pressure. Hurricanes are deep holes, again inverted. Anyway systems will follow the path of least resistance and that happens to be the valleys. A dry May in Florida indicates a stronger ridge to the west which means less rain and a later turn for any storm in the vicinity, if the ridge doesn't migrate to the east. Last year we had strong high pressure through the whole season. Thats how I envision whats going on but, I've been wrong before.
Bottom line is Lushine's discovery doesn't apply just to S. florida it applies to the whole Gulf of Mexico with less of a threat to the outer bank area. Even then timing is everthing or nothing.
| DarleneCane |
| (Verified CFHC User) |
| Thu Jun 05 2008 09:01 PM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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Was that the same set up when Betsy crossed through Florida into La?
I've heard that theory. Then again is there an indicator how far north that works?
How does a place like Savannah get hit by a storm? The high is holding tight across the whole SE part of the country.
| craigm |
| (Storm Tracker) |
| Thu Jun 05 2008 09:44 PM |
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Re: Increased S. Florida Hurricane Risk? - May Precip. Totals
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Quote:
Was that the same set up when Betsy crossed through Florida into La?
I've heard that theory. Then again is there an indicator how far north that works?
How does a place like Savannah get hit by a storm? The high is holding tight across the whole SE part of the country.
DC, You can never rule out a landfall anywhere along the east coast.
Watch this loop and you can see the fluid nature of the high and low pressure areas. When a storm turns north it is finding a weakness in the high pressure area.
The blue areas are low pressure and the yelow and orange are the highs. You can see how everything is constantly changing however the bermuda high persists over the Atlantic, during Hurricane season,with weaknesses developing periodically which allow storms to escape northward. This is a loop of the Navy model but you will see something similar on all of them.
http://moe.met.fsu.edu/cgi-bin/ngptc2.cgi?time=2008060512&field=Sea+Level+Pressure&hour=Animation