Will Lushine's SFL May Rainfall Theory Hold True For 2007?

[Blown Away]

A few more days left in May and SFL rainfall is below average. The May totals were above average during mid May, but the last week or so have been pretty dry overall, except for S Miami Dade county. I know it's not hardcore science, but it is an interesting theory and mother nature has to balance the water deficit in SFL. Come June 1, this theory will be officially on the clock.

http://www.insurancejournal.com/news/so ... tm?print=1

http://www.sfwmd.gov/curre/rainmaps/monthly.html

[wxwonder12]

what is May's total rainfall so far?

[Blown Away]

what is May's total rainfall so far?

2.47" for the SFL district, which is @76% of the average.

[Tampa Bay Hurricane]

We've had no rain this month...ok maybe .10 inch one day but
other than that it has not rained in over a month.
I look at this theory as a thermodynamic balancing
act.

Mother Nature may send a tropical system later this
season to balance the dry conditions out,
as dry and hot weather allow for more thermal
energy to accumulate, and that thermal energy
generates more moisture and unstable thunderstorms,
potentially enhancing the strength of tropical systems
in the vicinity of Florida for later in the season.

[JonathanBelles]

IT seems like more than a month. All that .1" ran off in the road anyway.

[WeatherEmperor]

I wanna take this one step further by talking about the huge ridge of high pressure that has been sitting over the SE states this spring. I believe this is the 4th driest spring on record for the SE states. I understand Lushine's theory talks about the less rainfall south florida receives, the higher the chances are of being struck by a hurricane. But what about the persistant ridge over the SE. Would that also increase the chances of a south florida hurricane strike?

<RICKY>

[windstorm99]

If you see the early pattern setup this late spring it looks to be a slow June. Shear levels look to be High as fronts continue to be driven down the East Coast of the U.S. Now will the last through July and August only time will tell.

[MiamiensisWx]

I wanna take this one step further by talking about the huge ridge of high pressure that has been sitting over the SE states this spring. I believe this is the 4th driest spring on record for the SE states. I understand Lushine's theory talks about the less rainfall south florida receives, the higher the chances are of being struck by a hurricane. But what about the persistant ridge over the SE. Would that also increase the chances of a south florida hurricane strike?

<RICKY>

That is the basis for the dry May theory. According to Lushine, persistent ridging reduces precipitation over the state of Florida. The month of May marks the typical transition to the rainy season in Florida. Surface ridging tends to reduce thunderstorm activity. In addition, persistent dry conditions could indicate the continued presence of a ridge over the Southeast. If these conditions are present (during May), this could indicate potential tropical cyclone strikes because of the development of an upper-level ridge. According to Lushine, the presence of strong ridging (and dry conditions) in May could indicate a pattern trend that may persist during the hurricane season.

I believe this is the summary of Jim Lushine's theory. Personally, I believe that its success rate is a mixed bag. Many wet Mays featured tropical cyclone strikes. Ultimately, timing is the key factor. I was simply explaining Jim's theory.

[WeatherEmperor]

I wanna take this one step further by talking about the huge ridge of high pressure that has been sitting over the SE states this spring. I believe this is the 4th driest spring on record for the SE states. I understand Lushine's theory talks about the less rainfall south florida receives, the higher the chances are of being struck by a hurricane. But what about the persistant ridge over the SE. Would that also increase the chances of a south florida hurricane strike?

<RICKY>

That is the basis for the dry May theory. According to Lushine, persistent ridging reduces precipitation over the state of Florida. The month of May marks the typical transition to the rainy season in Florida. Surface ridging tends to reduce thunderstorm activity. In addition, persistent dry conditions could indicate the continued presence of a ridge over the Southeast. If these conditions are present (during May), this could indicate potential tropical cyclone strikes because of the development of an upper-level ridge. According to Lushine, the presence of strong ridging (and dry conditions) in May could indicate a pattern trend that may persist during the hurricane season.

I believe this is the summary of Jim Lushine's theory. Personally, I believe that its success rate is a mixed bag. Many wet Mays featured tropical cyclone strikes. Ultimately, timing is the key factor. I was simply explaining Jim's theory.

Oooh okay I understand it better now. I want to ask one more thing. I believe around this time last year we underwent a pattern change that brought many fronts and trofs of low pressure down the east coast which favored a more recurvature situation. So far this year we have seen that high pressure just sitting over the SE. Are there any indications that we might see a pattern change this year?

<RICKY>

[MiamiensisWx]

Oooh okay I understand it better now. I want to ask one more thing. I believe around this time last year we underwent a pattern change that brought many fronts and trofs of low pressure down the east coast which favored a more recurvature situation. So far this year we have seen that high pressure just sitting over the SE. Are there any indications that we might see a pattern change this year?

<RICKY>

It is important to remember some key elements. Firstly, the persistent ridging has been at the surface. As tropical cyclones are steered by the upper levels, the current pattern would not bring well-stacked tropical storms or hurricanes into Florida. The ridging during May of 2004 was also a surface feature. In addition, timing is the key factor with respect to tracks. Upper-level ridging tends to establish during the heart of the season. Troughs can bring systems into Florida (see Ernesto, Cleo, and Wilma). Because of this point, I believe that the dry May theory has some weaknesses.

We may observe a pattern change over the next few days. As the current system over the Great Lakes erodes the ridging, we may get some precipitation during the first weeks of June. Despite this change, I believe that it's not always a good indicator of conditions during the season. The position of tropical cyclones (and the timing of troughs and ridges) is the most important factor. We should monitor conditions during the heart of the season.

This is just my two cents.

[MiamiensisWx]

The SFWMD region enters June with below average rainfall totals. A district deficit of 1.57 inches encompasses the south Florida region. Rainfall totals are below average throughout the area.

http://www.sfwmd.gov/curre/rainmaps/monthly.html

[JonathanBelles]

I think 92L will level some of the deficits somewhat.

[Aquawind]

I think 92L will level some of the deficits somewhat.

Nice way to start June alright! I am pumped for some falling liquid. Our precip chances at NWS just went from 30% tomorrow to 70%!

[hial2]

I think 92L will level some of the deficits somewhat.

but not in May!

[Blown Away]

SFL got alot of rain from Barry, 4+" in some spots, but the calendar May was very dry.

[Jinkers]

I've heard this analogy of dry May and a hurricane hitting south florida, don't remember where I heard it from, but I think it was soon after Andrew, someone mentioned it to me, so I've always wanted a wet May-lol

[boca]

Because of Barry it helped our situsation alittle but next week were back to hot and dry conditions just to erase what Barry did.

[windstorm99]

Yea boca temps in the lower 90's with 30 percent at best for rain chances.

[Stephanie]

The theory is interesting because I believe that alot of once drought stricken areas are only helped by tropical systems. Really think that there is some kind of correlation between drought and tropical systems because of Mother Nature's way of "balancing" the atmosphere.

[jinftl]

From NWS Miami stats for the month of May...all major reporting stations were below normal in terms of rainfall. Departures from normal were:

Miami -0.24"
Fort Lauderdale -3.49"
West Palm Beach -2.21"