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Good day everyone!
As I was publishing this synopsis, the SPC added a MARGINAL risk for Severe Thunderstorms in the Day 1 Outlook:
The Storm Prediction Center (SPC) has designated an ENHANCED risk of Severe Thunderstorms in the Day 2 Convective Outlook across much of MS…NWRN AL…WRN TN AND KY…EXTREME SRN IL AND INDIANA…
There is a SLIGHT risk FROM SRN IL AND INDIANA SWD TO THE CNTRL GULF COAST…
There is a MARGINAL risk IMMEDIATELY SURROUNDING THE SLIGHT RISK AREA…
Based on information contained in the outlook, and analysis of forecast sounding parameters and values using F5 DATA Severe Weather software, based on a combination of the NAM-WRF and GFS 06Z runs, some values are offsetting others. The SPC outlook indicates wind shear will be quite strong across the region, and stronger than instability. This setup based on forecast parameter definitions, generally hampers supercell thunderstorm development. On the other hand, forecast sounding data at the moment, shows SRH (Storm Relative Helicity) values at around 350 – 450, and STP (Significant Tornado Parameter) values of 3 – 6, within the outlined areas in the following maps, would indicate some storms embedded within the line in the enhanced risk area, could be tornadic. Based on the STP scale, values greater than 1 indicate the probability of significant tornadoes increases dramatically.
The affected region will be under the influence of a strong upper level (250 mb) jetstreak, on the order of about 140 – 160 knots. This pretty much creates strong divergence in the upper portion of the atmosphere, along with “tilting”, as mentioned in the SPC outlook. Tilting of the thunderstorm prevents rain from falling back into the “updraft”, which keeps the thunderstorm fueled. (http://www.tornadochaser.net/jet.html).
I will be looking at this again in the morning, with the new early morning runs…analyzing newer forecast soundings, and will try to have an update published before 11:00 a.m.
On a very brief note, the Arctic Oscillation is forecast to take a dip into the negative once more, but at the moment, doesn’t appear to be as strong of a dip as the previous. However, expect colder temperatures to once again head south during the next 5-6 days
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS