Potential for beneficial rainfall this week

bob

Thanks Mike. As you can see on the home page, just over a third of an inch of rain in Sw Cape Coral and glad to see it! Also good to see widespread rain with higher totals in most areas.

bob
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Sit back, relax and enjoy the show!

CONVECTIVEMIKE

Really inquisitive if all the rain we have gotten this winter compared to the dry winter last year here will lead to higher humidity levels and a deeper moisture laden layer causing better probabilities for t-storm activity this summer due to the ground having an increased moisture content. What do you think ?

alorfi

Unlike areas in the middle of the continent, latent soil moisture has very little impact on precipitation here in Florida given we are already surrounded by bathwater all summer long. Also, unlike most other places in the country, we actually receive MORE rainfall during the summer when larger-scale weather forces are benign. Most of our summer rainfall occurs as a result of collisions between the Gulf and Atlantic seabreezes. Because the Atlantic ocean is larger, the east-to-west seabreeze is stronger, so the convective activity down the spine of the peninsula generated from the collisions with the Gulf breeze typically move toward the west coast of Florida. This why we generally see late-day storms here on the west coast.

However, there are features that can distrupt this prevalent pattern... and we saw a lot of these "interruptions" last year. Any strong zonal flow (any synoptic feature that produces a prevalent wind direction) can preclude the seabreeze collisions. For example, a low pressure rotation to our north will result in a prevalent WSW flow, so any showers that develop over us will quickly move inland and we miss our afternoon convection. Sometimes high pressure can cause subsidence as well. Tropical systems tracking north of us completely mess up our seabreeze interactions and usually result in unbearably hot and rain-free afternoons.

Our wettest summers occur when we have few disruptions to our "normal" pattern. This entails a strong Bermuda high that yields a prevalent ESE flow drawing deep moisture from the Caribbean that collides with the Gulf coast sea breezes. These slow-moving storms dump copious amounts of rain and once this pattern establishes itself, it can last for weeks. Last year was so dry, in my opinion, because we never saw high pressure off the eastern seaboard until July and we kept having interruptions from other features.

As for an outlook toward this summer, I would think the cooler ocean temperatures could lead toward more benign synoptic features and that would yield above-average rainfall. But of course, convective activity is so localized that forecasts rarely verify in one particular spot. I had called for above-average rainfall this winter, but some areas keep getting missed while I'm looking at 12.01 inches since Dec. 1 at my station in North Port and 10.46 inches during the same time period at another station in Punta Gorda. Here in the Cape, I'm at 4.38 and areas to our south such as Naples are in the 7-inch range. Obviously, you folks up in the Tampa area have enjoyed a very wet winter. Go figure.

CONVECTIVEMIKE

I was recently looking today at the Seasonal Outlooks that are up on the Climate Prediction's page and they are pointing to an extremely hot and dry pattern for us in Florida unntil Early Autum(September to be exact) with only precipitation increasing for the upcoming Autumn and Early winter whilst temps are still going to be abaove avg until Dec. when next winter is supposed to be Normal for Florida standards

alorfi

Again, our primary mechanism for rainfall during the summer is the seabreeze interactions in the middle of this unusual peninsula, so long-term seasonal outlooks are worthless during the summer. During the rest of the year, we have "normal" weather, meaning, our rainfall occurs primarily from cyclonic systems and frontal boundaries, but our summer weather is so different from the rest of the continent that seasonal outlooks are inapplicable.