The Graphic you see above was issued by the Storm Prediction Center valid for Thursday. A large portion of the Delta is encircled in the Moderate Risk Area.
The above graphic is a Helicity Forecast from the NAM. Helicity describes the turning of the winds with height. You may also hear this described as "Streamwise Vorticity." Directional shear is very important in the development of Mesocyclones, which produce Tornadoes. Seeing Helicity forecast this high by the models is very impressive.
The clincher for this system is the track of the low. The Guidance is not in agreement on the placement of the Low Pressure. The position of the Warm Front will be a big player in the highest risk areas for Tornadoes.
The European Model forecasts a nice Jet Streak in position over the threat area. The risk area is beneath the right rear quadrant of the Jet Streak, which means the winds are diverging aloft. Diverging winds aloft, means convergence at the surface (Good for Storms.)
Above is a forecasted sounding from the NAM for Thursday night in Greenville, MS. The Models are terrible at forecasting the Thermodynamics for a severe storm event, but something to note is the amount of moisture present throughout the entire column. The green line is Dewpoint, the red is Temperature. The closeness of these lines represents high Relative Humidities. Thunderstorms with strong updrafts can tap into this moisture column and produce heavy rainfall rates. There is no deficit for moisture with this event.
The heaviest rainfall should be in the Northern portion of the Mississippi Delta. The best uplift mechanisms are still well to the north of us, but that doesn't rule out severe weather at all.
I'll post some more information later today as things get fine tuned. Please Comment!
No comments:
Post a Comment