javier rosa department of marine and environmental systems florida institute of technology

Sea Breeze Initiated Thunderstorms Relating to Convective Available Potential Energy (CAPE) and

Convective Inhibition (CINH)

Javier Rosa Department of Marine and Environmental Systems

Florida Institute of TechnologyMelbourne, Florida 32901

July 16, 2008

Overview

• What is the purpose for this project?• What is CAPE/CINH?• Why look at CAPE/CINH?• How are values gathered?• Where is area of focus for this project?• Is there a threshold for CAPE in thunderstorms?

Purpose

• Find a threshold for CAPE values in thunderstorms initiated by the sea breeze

• Provide ability to forecast sea breeze thunderstorms using CAPE as a predictor

What is CAPE/CINH?

• CAPE is the integrated area of positive buoyancy

• CINH is the integrated area of negative buoyancy

• CAPE = Instability• CINH = Stability

Why look at CAPE/CINH?• CAPE is needed for

thunderstorm development (accelerating motion)

• CINH can limit thunderstorm initiation (decelerating motion)

• Previous study indicated threshold values for CAPE (Solomon, R., and M. Baker, 1994)

Sounding DataLaunched 3 times a

day (5 AM, 11 AM, 5PM)

CAPE = Positive Buoyancy

CINH = Negative Buoyancy

Most Unstable parcel was used for project

CAPE

CINH

North American Mesoscale (NAM) Forecast Model

• NAM is an atmospheric prediction model

• NAM forecast runs every 6 hours with 3 hour forecast intervals up to 84 hours for each run

• 12 km resolution

1600

1700

1800

1900

2000

2100

2200

2300

2400

2500

Area of Study

• The area of study includes the Cape Canaveral region and its surrounding areas

Methods• Locate sea breeze

thunderstorms using Melbourne radar reflectivity

• Get CAPE and CINH values using sounding data and NAM forecast model

Sea Breeze Boundary

Thunderstorm Initiation

Thunderstorm Initiation

Additional Thunderstorm Initiation

More Storm Initiation

CAPE Statistics Using NAM Forecast Model

-Not statistically different-Cannot differentiate between yes and no cases

CAPE Statistics Using Sounding Data

-Not statistically different-Cannot differentiate between yes and no cases

CINH Statistics Using Sounding Data

-Not statistically different-Cannot differentiate between yes and no cases

Conclusion

• CAPE is not a good predictor of sea breeze thunderstorms based on data set

• CINH was not a factor in limiting thunderstorm initiation

Any Questions/Comments?

Takashi Kida

References• Wilson, J.W., and D.L. Megenhardt, 1997: Thunderstorm

Initiation, Organization, and Lifetime Associated with Florida Boundary Layer Convergence Lines. Mon. Wea. Rev., 125, 1507–1525.

• Weisman, M. L., and J. B. Klemp, 1982: The dependence of numerically simulated convective storms on vertical wind shear and buoyancy. Mon. Wea. Rev., 110, 504–520.

• Solomon, R., and M. Baker, 1994: Electrification of New Mexico Thunderstorms. /Mon. Wea. Rev./, *122*, 1878–1886.