FLOOD WATCH IN EFFECT FOR THE NEW ORLEANS AREA THRU THURSDAY

[bfez1]

A low pressure system is expected to develop over the plains states
today and move east toward the Gulf states. The upper level wind
pattern in conjunction with moist Gulf flow near the surface... will
become increasingly favorable for heavy rain by this evening. A long
duration episode of rainfall is anticipated with onset Wednesday
evening and continuing intermittently through Friday morning.

Average rainfall amounts of 3 to 6 inches are expected in the watch
area with localized higher amounts possible. The greatest potential
for flooding is expected to be 24 to 30 hours starting late this
evening through Friday morning. Excessive rainfall would cause
several of the area's river basins to be sent into flood meaning once
the Flood Watch expires Friday morning... river flooding problems may
continue or even worsen.

[Rockstock]

Since you are in New Orleans talking about the weather, I will do some math for your atmosphere for worst possible time for an event. Ill post the Times and Math here..Ill start now.

Kevin Martin

[bfez1]

Great---thank you!

[Rockstock]

NEW ORLEANS MATH FORECAST FOR THURSDAY AFTERNOON FROM 12pmCST to 6pmCST EVENING.

This is a 6 hour period forecast.

Dewpoint Forecast shows a dewpoint at 60= 50%
Surface Temperature will be at 67 degrees= 20%
Low Level Jet inflow at 850mb will be at 40-45 knots= 50%
Surface Moisture Carrying Wind= 100%
700MB Dry Air Carrying wind= 100%
Upper Level Jet Stream will be blowing at 105 knots= 50%
500MB vort values= 20%

Probability of Severe Thunderstorms is 56%
So with that 56% it corresponds with my charts on........

Moderate/High Severe Thunderstorm Risk
On a weather map, it would be SEVERE red shading.
Thunderstorm probability is 70%

CAPE=50%

HELICITY=250-300 WEAK TO STRONG TORNADOES POSSBILE!
HIGHEST VALUE F2

Hail values.

75%
100%
75%
75%
50%

added together is 375 or...

Greater than 3/4 inch hail size expected!

Forecast Discussion for the 6 hr period.
A pretty interesting setup you have. Dewpoints will meet up with the temperature to make the atmosphere unstable to support Thunderstorms. The CAPE values are to be near 1500 j/kg..This area will have the highest CAPE during the 6 hr period. Showers and Thunderstorm will develop. Out of the Thunderstorms that Develop, there is a 56% for each one to become Severe. Jet Stream winds will be nearing 115kts. Latest Precipitaion estimates to near 2 inches during this period. More accumulations within Thunderstorm vicinities. The Helicity Levels will be enough to support Rotating Thunderstorms. Supercells are possible with Weak to Strong Tornadoes. The levels show the highest possible tornado would be an F2 Rating. The most helicity is to the Northeast of this area, and well out of range for Violent F4-F5 Tornadoes.

I would putting a Severe Thunderstorm Watch for this period.

Not sure for the Tornado Watch just this yet. But if there was a Tornado Post Watch,lol, i'd be putting one down.

Kevin Martin

[JCT777]

Kevin - your analysis is outstanding. I hope you will be able to continue to contribute this type of analysis for many of the severe wx episodes during the upcoming severe weather season.

[Rockstock]

Yeah, Of course. Severe Weather Season is my chance of getting out of California for a while always. Ill be using this during that period as well while chasing. going to be fun, can't wait

Kevin Martin