"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"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".

Wednesday, January 26, 2011

Big Weather Gone Now - But What Really is SEVERE Weather?

(1) Squall line associated with a pre-cold frontal trough of low pressure is embedded with weakly rotating storm pockets is shown in the first image as it crossed East Central Florida during the early evening yesterday.
(2)The second image is taken from WESH TV (Channel 2) with my digital camera as the area approached the intracoastal of Brevard County. The black boxes show the tornado warnings in effect at the time due to the rotations aloft being displayed by Doppler Radar at the NWS in Melbourne, FL
(3) In sharp contrast, the third image is the radar display at 9:15AM this Wednesday morning showing a line of light rain showers associated with the actual cold front proper . BIG difference in radar displays, huh?!
(4) Lastly, the final image is the average mid-level winds and moisture content of the atmosphere throughout just after the time of that second radar display. We see that there is definitely a cold front with moisture decreasing pretty quickly at those levels behind the boundary defined by the drying air mass as it continues moving toward the Southeast. The front was accompanied by an up tick and slight shift in the surface winds and some partial clearing sky conditions. Gusts near 40mph I read somewhere were reported.

RECAP: For the most part, Florida was spared from a situation that could have evolved into a situation much worse than what eventually materialized yesterday. From my perspective, it made for some fun radar viewing, but when the actual activity reached my spot the actual event was nothing more than some rain and a few in cloud lightning flashes. From radar you'd swear it would be much worse. Not everyone had the same experience though.

It is important to understand, that in all discussions here, to recall that the words "Probable' "Could" and "Should" are used most often. Had this been a situation with a high degree of confidence, you would have read (and likely heard though the media) worlds like WILL and IS GOING TO. The potential was there, and could have been higher, for a wide spread severe weather event on Tuesday, but all the elements never did come together over a broad expanse, and just barely did in isolated fashion and when they did the weather elements were poor considering what they are in a certain severe weather event. Which in Florida, compared to the Great Plains, is relatively rare.

But in looking at the Storm Prediction Center's (SPC) Storm Log and the National Weather Service (NWS) Storm reports, the worst of the weather did occur in the area that I had highlighted for yesterday and the day before that, as having the greatest potential for active weather. (note that I just used the word "potential" in that last sentence). The Big Daddy of weather elements was in the form of the expected marginally severe wind gusts, and in at least one wind event recorded near Tampa, flat out straight line winds perhaps as strong as 90 mph for a very brief time.

I am having a hard time getting down to EXACT details this morning, since the SPC storm logs aren't quite in sync with the Storm Reports just yet, namely because new information is still filtering in 'the morning after' while NWS employees head out to assess damage in a few locations and determine what caused that damage (winds or a tornado).

A funnel cloud was observed from Patrick AFB during the storm cell that traversed across the Viera (and lofted someone's backyard trampoline down the street for several hundred yards). Interestingly, the funnel was observed through the use night-time vision goggles!

With this given, best I can tell there was either 2 or 3 tornadoes and a waterspout all over by the Tampa Bay Region, and a tornado near Alva, FL in Lee County (which originally came in as wind damage last night). A few funnel clouds were reported, but whether those were truly funnels or someone not knowledgeable of what they were seeing will remain the great unknown, but pictures would help (even though those can be misleading too, and have been used in the past to "fool" the unwary as portraying a "Sheriff 'Nado"...or tornado look alike that is acutally just scud clouds).

There was 1 injury related to wind damage. My guess is that the tornado that caused damage (I believe the other/others were over open areas) will be rated either EF0 or EF1 on the Enhanced Fujita Tornado Rating Scale. That information will probably be made known today if it isn't already. Far cry from the EF3 tornadoes that hit Central Florida in late February, 1998 and the last strong one I can recall more recently on Ground Hog's Day, 2007.

There was a few hail reports of 0.70" (dime sized) hail (non-severe), and I believe one of 1" near Brooksville (which is considered a size that can be damaging, thus appropriately deemed severe sized). But if you were watching TV last night, you might have noticed that 1, 2, and did is see a 3" (?!) hail size potential being broadcast? These are radar based estimates and measured by Doppler radar well aloft in the atmosphere. But I didn't hear the word "potential' much. Had hail of that size reached the ground as widespread as some folks might have been misled to believe was occurring, this would have been a significant weather event (not even touching the wind side of the story).

Same thing goes with the wind being portrayed. Use of the Doppler Radar came in very handy for providing more than sufficient lead time warnings to the public. Indeed, wide spread marginally severe winds were measured across Central Florida, and a high percent of those state wide occurred in the greatest threat area outlined in previous blog posts (Central Florida from Tampa to Brevard) . There was something like 20 -21 wind reports that have been officially categorized 'Severe" - equal to or greater than 58 mph.

The "severe" category comes in to play for both the wind and hail category because it has been determined through extensive research that when either of those parameters reach a certain threshold damage can result. Thus, as interesting as a deluge of pea sized hail can be while experiencing almost constant lightning and a hard blowing wind, that is not 'severe' by definition. It might be scary, but "Scary Doe Not Equal Severe" (all the time).

RAINFALL: I received 1.60" inches of rain, most of which fell with passage of the squall line. In viewing over civilian/volunteer reports transmitted to COCORAHs (The Community Collaborative Rain, Hail, and Snow Network)...this total was just above averaged totals reported over a vast expanse of Florida. The area that received the least was the Panhandle There were a few reports over 3", but not where the Doppler Radar estimate showed it to be (NW of Daytona Beach). Probably because no one lives at that location who reports or has a rain gauge.

TODAY: As noted by the images above, a cold front went through close to 10AM this morning. Winds just over head are 30-55mph today and some strong gusts accompanied the front as a result. But as the low pressure center culprit for yesterday's weather pulls away during the course of this afternoon along the Atlantic Coast to just east of New York City by this evening, the pressure gradient will relax by late afternoon and the mid-level trough supporting those winds and overhead early today will also be lifting north. So essentially, winds will decrease most notably after peak heating today.

Cloud Cover: It is totally cloudy as I type right now. But in looking at the latest surface observations, and viewing the visible satellite imagery, as well as other upper level information...skies may very well be clearing over my head as I click on the " Publish Post" button for this very post. In other words, rapidly clearing sky conditions early in the afternoon, working South during the afternoon.

Temperature/Wind Regime: Wind to remain mainly due west today at 12-20mph with gusts to just above 30mph early, with winds and gust progressively decreasing throughout the day. Winds becoming more NW over night but light. No wind over 15mph foreseen beyond today through this time next week. Temperatures today will portray wide spread mid-and some upper 60s (warmer start further south so they will see low-mid 70s before frontal passage then level off). Temperature will fall below 60F as the sun sets and only slowly fall through the course of the mid-late evening, with the majority of our remaining woken hours in the mid 50s.

THURSDAY: Temperature will take a steeper drop after midnight when the driest air will have moved in. Cool to cold (depending on one's sensitivity to the lower dew point air/some light wind/temperature combination), with the mercury in the low-mid 40s over a vast expanse of Florida real estate. Colder far north.

High pressure will be nosing SE from the U.S. InterMountain Region toward the western Gulf of Mexico, then east across the Gulf of Mexico during the weekend with no other systems of 'wet nature' to impact the state for quite some time to come. The Caboose to the Train of Weather Makers the past two weeks has pulled out of station as of Frontal Passage this morning!!

BEYOND: We will see perhaps two or three more weak, elevated cold fronts pass across the state in days to come which will break through (at the surface) the high pressure building east ward across the Gulf of Mexico. At time, high pressure will be directly overhead the state which would lead to a few mornings of a frost potential further north if it is overhead at daybreak, but either way the net affect of the two combined will mean a brief period of more northerly winds and colder air, followed by westerly winds and modifying (slowly warming) temperatures. But all in all, once we take the baby out with the bath water, on average we'll have lows in the 40s and highs in the 60s with temperatures uniformly spread a few times to even the far Southern Portions of the state. A morning or two might have the same morning low in Central as what is felt as far south as Miami. But they'll see the warmer afternoon highs back into the 70s first. Some periods of high cirrus clouds will be thrown into the mix as well, but lack of a more moist, onshore wind component for any respectable length of time will preclude formation of a prolific, coastal stratocumulus deck of clouds.

BEYOND, BEYOND?: Don't forget, I keep the Magic 8 Ball handy for those long range outlooks, that are so far "Out There" that even a High Powered Telescope strong enough to see craters on a planet in another galaxy (do those exist?) can see them with clarity. But we are likely still in a drought despite the rainfall of yesterday that equated to probably no more than a drop in the bucket in the long run. Thus, we need to look for another chance of rain. Right?!

For now, watching the storm breeding ground of the Texas Gulf Coast by this time next week. Chances are appearing, but the view is still fuzzy and the 8-Ball is getting dusty, that another short train of systems might be in the making after 6-9 days rest of vacation time away from the state. But wet storms in Florida in February? Sometimes, not so good from the severe weather aspect.

More concerning Florida's Severe Weather Potential in the weeks to come in another post before the weekend. We are just now entering the more climatologically favored time period for Synoptic Scale Severe Weather (i.e, not of the small scale/micro-mesoscale type associated with summer thunderstorms).

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