"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".

Tuesday, January 25, 2011

Severe Weather 'Potential' Remains Likely For Florida Afternoon/Overnight

If seeing this post on Facebook, you can read the description of what the lines I have drawn in the first (of two images) indicate by opening the link. These are solely of my own doing and are not official by any means. But I would like to mention that this graphic was created prior to seeing the latest official outlook. Also included in this brief post is the latest official Outlook issued by the Storm Prediction Center (SPC) located in Norman, Oklahoma this morning around 7:30AM. Note the similarities in the two images.

The time period for the official outlook is roughly valid from 8AM today to 7AM Wednesday.
morning. The image I have drawn is valid from Noon Today through 2pm Wednesday. So what do those lines mean?

QUICKLY LET'S CUT TO THE CURRENT: To get current this morning, very little change from yesterday's post in regards to when, where, how activity will manifest today/overnight. As we see, I've chosen a wind shift line correlated with the 2 meter ambient air temperature to determine where a developing warm front is located at 7:45AM this morning (the time does not show on the cropped image extracted from the NWS MLB website). It is located very close to where it was reckoned it would be at this time today in yesterday's post. The front is merging with that persistent inverted trough (that was located near the Cape yesterday and the day before at this time) and is pressing north.

By shortly after noon time it will be along the I-10 corridor and eventually make it as far north as South Central Georgia by late this afternoon. Highest dew point air is along the East Coast from just north of KSC to Miami and through the keys. Not much different far south if at all from that at KSC where close proximity of the Atlantic has made all things equal. Expect that within a few hours the entire 60F degree dew point isotherm will be where the warm front is drawn on the image with low and mid 60s dewpoints across the entire state, rising throughout the day. Otherwise, gusty SE-SSE winds becoming southerly late in the day. Highs in the low-mid 70s, warmer South Central and inland.

TODAY: We will have innumerable items of interest at play today and overnight each contributing to storm activity in a variety of convective modes within two distinct time periods. Now for the lines on the first image:

1) The yellow lines depict mode 1 to begin near noon time toward the west coast with conditions conducive for additional development quickly spreading east across all of Central within the bounds of those lines between 1pm -3pm. This will be discrete rain shower and thunderstorm activity, some strong with isolated severe activity. Storm motion should be from the S-SSW around 30-35mph, perhaps even faster. Believe that by this time Central will possibly be in a Severe Thunderstorm Watch, although it may be deemed by SPC that such level of intensity in the storms will be too spotty for a watch issuance, and as such leave it up to local National Weather Service offices to issue warnings as they deem fit (like is done during the summer).

2) We could see a brief break in activity over the east side of the peninsula for a time early evening when an already developed broken squall line will be entering the west coast between 7-8pm along a pre-cold frontal trough. Associated with that boundary will be the strongest combination of mid-level winds which will rapidly overspread the peninsula. Believe that by late afternoon a Tornado Watch will have been issued if not sooner.

WHITE LINES: At this point it is likely we will have to switch solely to mesoscale mode and constant monitoring to watch boundary interactions within the broad line itself for the most active weather as it crosses the state. With that in mind, be attuned to your most favored media outlet, as I highly doubt folks will be glued to the computer for the intricate details concerning the 'why's in regards to what or will shortly unfold.

Although a broad expanse will be impacted in some form or another by this 'line', it looks the best ingredients combined for a potential tornado and strong straight line winds will occur within the bounds of the white lines drawn although as said activity could occur outside of these bounds as well. This would be for the 7-8pm (west side) Curtain Call through the final 5AM Encore (East Central side). 7AM - main show's over.

BLUE LINES: Additional areas of potential severe weather ending far southeast by early-mid afternoon. Believe the brunt of 'the worst' will be off the coast at sunrise Central, if not sooner. But the line of activity will have yet to clear the Southeast zone from West Palm to the Keys.

BLACK LINES: Entire area from beginning to end of period that could have strong storms.

Do not believe hail will be an issue this go around, although some small-non severe sized hail is always possible. Believe this will be primarily a marginally severe wind event. Although shearing wind profiles (and veering with height initially along and ahead of the pre-cold frontal trough) will be at play, they won't be tremendously strong. However, due to the broad swath of these profiles coexisting within a homogeneously moderately unstable atmosphere sustained, rotating storm structures are easily possible which could result in a tornado. Should wind fields come together just right in a concentrated area within this environment, a single storm entity could produce more than one tornado as it takes the trek across the state, or simply put one down and keep it it rides along a mesoscale boundary laid out by surrounding activity.

RAINFALL: Virtually, at some poin,t everyone will have had measurable rainfall when all is said and done. Although there is a touch of doubt extreme far SE. But rainfall totals will vary tremendously contingent upon where the heaviest storms track over Central and South. To the north, the rainfall will be most persistent thanks to strong isentropic lift along and north of the warm front and insanely high helicity values north of I-10.

Big totals seem guaranteed near the north side of Tampa Bay toward the Brevard/Volusia County border, approaching 2.5 -3' here and there , then spottier 1- 1.5" amounts along where the southern extent of the yellow line is drawn, with the most common rainfall totals surrounding these higher totals between 0.5 to 0.75".

New data is yet available at the time of this post, so an additional post or two could follow later today. But do believe, and hope, that folks stay tuned to the TV or have an operational weather radio (with S.A.M.E. alert) in stand-by mode nearby.

BE ADVISED!!: Storm motion will be fast around 30-35mph at least, perhaps up to 40mph at times, so if you can hear thunder approaching, the storm is only a few minutes away! If you are in a severe thunderstorm or heaven forbid, a TORNADO WARNING, heed them! Severe Thunderstorms (particularly the ones that might form over night) can suddenly evolve into tornado producers as they are about to cross over any particular spot on the map, lest that be your house.

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