"But seeing they could not See; hearing they could not Hear"
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"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

"The wind blows to the south and turns to the north; round and round it goes, ever returning on its course".

Monday, July 12, 2010

"Surf's Up!" But It's a Small Swell

(Image: Averaged moisture/winds aloft show wave one is passing and another is on the horizon)
Surfers know that the waves associated with an ocean swell come in sets. The same can be said for atmospheric waves of energy associated with a storm system or synoptic weather pattern but which are much more complex due to underlying thermodynamic principles (at a bare minimum).

REVIEW & SYNOPSIS: Central Florida is in between waves this morning as a fairly rare July swell swoops overhead. The first wave of the set came across yesterday and is currently exiting the area as the next one is already on the horizon and breaking on the reefs along the Alt 27 corridor from near Steinhatchee/Deadman's Bay toward Ocala.

On a broader/ general scale, high pressure is center over the Central Gulf of Mexico with another center well east of Bermuda. The systems are just barely connected by a ridge of high pressure near the surface that runs well off the East Coast and through the Florida Straits. Over the state and north of this axis exists a generally flat to slight troughiness in the mid-levels. The source of the swell actually exists well out in the Plains region which is generating the waves and sending them toward the SE U.S. They dampen out as they approach Florida and are just barely providing us with a passing blow...but just enough of one to make things interesting (surfable).

TODAY: First off and most notable is the PWAT value from KSC's latest sounding. Remember when PWAT was down to 0.86" (dang low)? Today it is at 2.24" which is remarkable from a moisture perspective and reminiscent of the values we had two weekends ago when it was cloudy all the time. As such, it is cloudy as I write at mainly the mid-levels..but areal coverage has been decreasing during the past 3 hours per IR satellite loops.
It was quite hot yesterday in some locales with Melbourne tying a record high of 97 (Miami also tied their record high of 95). KSC also reported 97 with a heat index of 115 degrees before the storms moved in. Such will not be the case today due to the lingering cloud cover and generally 'stirred up' atmosphere overhead in the wake of yesterday's wave. Overnight low in Canaveral was 80 degrees (PAFB eked out a 78 for an hour right at sunrise) under the clouds which prevented release of the heat into the atmosphere.

Today will be yet another anomaly type forecast unrepresentative of the typical sea breeze/lake breeze initiated type least initially. Once again, we will have a later onset of the sea breeze today..but not anticipating it will be quite as late as yesterday. Somewhere between 12:30-1:30pm at latest. Highs will make it to near or slightly above 90F across Central Florida, but further south where the moisture just moved in since last night but skies are much clearer they will be flirting with records once again.

In general, skies will clear more during late morning as the first wave moves further away, heating commences, and NVA (negative vorticity advection) clears out. But the next wave will already be on the wax up. Just how this wave will break is in question though.
Everything hinges on (1): how much clearing (and thus heating) we get and thus when, where, and how strong lake and sea breezes release in earnest and begin to have an impact on the surrounding geographically prone areas, and (2): how much this approaching wave will dampen or even strengthen during the course of the early afternoon and thus stirs the atmosphere throughout the layer proportionatly.

The very general low down though is that we can expect a broader area to receive rain today. Cape Canaveral received 1.39" inches yesterday whereas areas very near by received only a trace to none. There was none south of Melbourne - West Palm yesterday as an example. But the first wave opened the moisture gates so today expect they will have a good shot at storms too...just later in the day into the early evening hours.

With heating of the day with some cloud clearing, with what's left of the approaching impulse (wave), sea breeze initiation with heating, tons of moisture around, and nearly 0 convective inhibition we can expect a shot a storms pretty much anywhere along the east coast from West Palm to Jacksonville..the further north one goes the earlier it will be.

Not expecting severe storms, but wouldn't be surprised if some SWS (Special Weather Statements) need to be issued for either localized flooding where some training of storms could occur or for strong wind gusts. On the other head, it wouldn't hurt to be aware that there is the ever so remote chance of a funnel or waterspout should the primest of small scale mesoscale accidents occur.

TOMORROW: Probably the same scenario at play but with much different potential results. For now, we'll leave it there will be another chance of storms since the swell will continue, but just how the wave breaks when it reaches the coast cannot be determined until that wave materializes.

WEDNESDAY: The swell ends and we start to return to a more climatogically generic weather pattern and surface ridging resumes in earnest initially dead overhead then further north toward Friday. There are signs that much of Central Florida could be in an atmospheric 'shut down' later in the week with no storms or showers to speak of...but at this time such notions should remain mute.

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