Those of you in the JAX area please read:

[USAwx1]

the JAX nexrad has detected both a mesocyclone and TVS (tornado vortex Signature) with a cell entering Nassau county FL from the west. This storm is capible of producing a tornado, may have hail to 1" w/ it and wind gusts greater than 60 Mph.

it's moving to the ESE at about 7 KT and will probably miss the JAX area to the North and move out to sea.

Nassau county is under a tornado warning until 645 PM EDT.

the area remains under a severe thunderstorm watch until 9 pm edt.

[Lindaloo]

Thanks USA! Heads up Jek and Mary.

[USAwx1]

That cell has now moved into northern DUval county where a tornado warning is currently in effect.

[Anonymous]

Well, looks like most of the worst storms have moved off the coast now...

Code: Select all

 AT 615 PM EDT THE GENERAL PUBLIC REPORTED A TORNADO OVER DOCK
JUNCTION. RADAR INDICTED THAT THE PARENT THUNDERSTORM WAS MOVING
EAST AT 20 KNOTS.


Storms trying to refire along the line north of Jax... But I think that will be short-lived due to it being late in the Evening. there were many reports of severe weather around Jax earlier in the day as well including a funnel cloud in Union county. Most active I saw though was trash cans being blown across Beach Blvd

[Stormsfury]

Very unusual to see such strong TVS signatures this far south considering it's the dead of summer. However, it's also very unusual to see a 100kt jet in the upper levels diving this far south (with this unusually amplified pattern as well) ... the very strong diffluent flow will continue throughout the weekend, and a new SFC low will probably develop and keep things very active for the next several days across the Southeast, eventually working northward back into the Mid-Atlantic by the weekend.

SF

[USAwx1]

That's an unusual situation also. To have a system which resembles a nor'easter at this time of year.

[Anonymous]

Very unusual to see such strong TVS signatures this far south considering it's the dead of summer. However, it's also very unusual to see a 100kt jet in the upper levels diving this far south (with this unusually amplified pattern as well) ... the very strong diffluent flow will continue throughout the weekend, and a new SFC low will probably develop and keep things very active for the next several days across the Southeast, eventually working northward back into the Mid-Atlantic by the weekend.

SF

Any chance then for more severe weather next few days? SPC doesnt have Jax in a Slight risk area tomorrow or Saturday... But NWS Jax seems to think at least that we are going to get wet especially Saturday.

Code: Select all

FRI...LACK OF ORGANIZED PVA WILL LEAD TO LESS BUT MORE UNIFORM
COVERAGE OF MAINLY AFTN TSTMS. HOWEVER...THIS FCST IS CONTINGENT ON
NO IMPULSES MOVING RAPIDLY SE ON BACKSIDE OF ABNORMALLY DEEP ATLC
TROF. NEEDLESS TO SAY...THERE IS A LOT OF UNCERTAINTY WITH THIS
FCST. MAV MOS SHOWS VERY HIGH POPS...WITH MORE THAN 80% ACROSS S
ZONES. THINK THIS IS OVERDONE...BUT ALSO DON'T BUY LACK OF
SIGNIFICANT POPS IN ETA. SO...WILL USE GFS PRECIP FIELD BUT SCALE
BACK ROUGHLY 20%. THANX FOR COORD MLB/TBW!

SAT...MODEL DIFFERENCES CONTINUE WITH GFS DEVELOPING SIGNIFICANT SFC
LOW NR KATL. NO SUCH DEVELOPMENT IN ETA SUITE. HOWEVER...MOS NUMBERS
CLOSE SO WILL GENERALLY BLEND WITH ROUGHLY 60% AREA-WIDE.

[Stormsfury]

Jeky, that excerpt from JAX is an excellent writeup.

Let's start with the lack of organized PVA (positive vorticity advection). discussed in the AFD. Unlike the last couple of days, the organization of convection won't be as substantial, and more in the order of what we'd typically see in summer.

However, a precautionary note to add ... models do not pick up discrete little pieces of energy (or s/w = shortwaves/ripples/etc.) very well and especially in fast flow such as this with this unusually deep trough. And IF an undetected ripple in the NW flow rounds the base of that trough, well, all bets are off, and another round of particularly nasty weather could affect the area ... otherwise, expect more of the typical (maybe slightly better than normal chance of convection, however) diurnal convection.

SF

[Anonymous]

Cool-sounds good, thanks

[Josephine96]

Is only North Florida in the potential severe weather threat? Or may we get some too..

I know we can actually have tornadic thunderstorms sometimes from our seabreeze collisions but I was just curious lol

[Stormsfury]

Is only North Florida in the potential severe weather threat? Or may we get some too..

Best dynamics lie in Northern Florida and to get that strong of a jet streak (stream) that far south in July would be asking for snow in Southern Florida in winter ... extremely rare. However, the high heat and humidities with local boundaries along with at least some decent mid-level streaking, and healthy divergence aloft should enhance the threat for any convection that can get going down there could easily be severe, but probably not tornadic.

I know we can actually have tornadic thunderstorms sometimes from our seabreeze collisions but I was just curious lol

And most all of Florida's tornadoes come from the collision of seabreeze boundaries and/or outflow boundaries meeting, clashing, and/or converging upon one another, and most are short-lived, relatively weak tornadoes ...

SF

[GrimReaper]

Where was I when all this was going on???? I might be down in St. Johns, but I didn't hear any of this. Well looks like today might be just as fun!!! Hang on Jek,my friend!!
-Grim