Severe Weather Situation #006

Severe thunderstorms are popping up in Central Texas at this time.

At 7:33pm CDT... GOES satellite data and radar confirmed strong to potentially severe thunderstorms were in Central Texas.

These storms have warranted severe thunderstorm warnings at this time.

Threats out of these storms include... Golf Ball size Hail... and damaging winds in excess of 60 mph.

Specific Concerns...

A severe thunderstorm in ECTOR COUNTY in West Texas is showing a combination on velocity radar indicating that weak rotation may be occurring.

People in ECTOR COUNTY and in WEST ODESSA...ODESSA...GOLDSMITH...NORTH COWDEN...GARDENDALE will be affected by this storm.

This storm is also producing cloud to ground lightning.

Weather Explained: Lapse Rates

What are Lapse Rates?

Lapse Rates is what tells the decrease of temperatures the higher you go in the sky. It is also a measure of instability. The more difference there is between levels, the more instability there is.

How can you tell if the atmosphere is unstable?

Values in images less than 5.5-6 degrees in the images are considered very stable, while values near 9.5 degrees is considered incredibly unstable.

Below is a Sample Image from March 18, 2011.

In this image, we definitely see good instability in the Plains into the Midwest.

March 18 Severe Weather Forecast Discussion

This is a forecast discussion concerning a potential severe weather event early next week.

FORECAST DISCUSSION

We do have potential for a severe weather event, mainly across the Central Plains west into the Southern Great Lakes.

I'm sure you are wondering what the heck that image above means.

Well, that image is a picture of the 12z GFS Lapse Rates. A Lapse rate is the temperature change with height. The faster the temperature decreases with height, the more unstable the atmosphere is.

In the Central Plains, there does appear to be a good deal of instability as the temperature may be rapidly decreasing with height.

The Weather Centre feels this time is the appropriate time to issue a Severe Weather Event Image (SWEI). The SWEI is below.

The Weather Centre has outlined the Central Plains to southern portions of the US as the greatest potential for a severe weather event. The Southern Great Lakes and Midwest portions are also under a lower potential for a severe weather event. The image below represents the risk level for the Greatest Potential area on Monday.

This has been a forecast discussion from The Weather Centre.

Slight Radiation reaches Sacramento, CA

Traces of radiation have been found by monitors in areas of Sacramento, California. These traces are from the damaged nuclear facilities in Japan.

At this time the traces are far below levels that would harm humans.

March 17 Severe Weather Forecast Discussion

This is a Forecast Discussion about a potential severe weather situation in in next week's midweek.

OVERVIEW

Enough energy may be available Monday-Tuesday so that strong storms may develop. Possibly in the form of a squall line.

LIFTED INDEX

A measure of the lifted index is a measure to tell how unstable the atmosphere may be. When the Lifted Index goes below 0, that is when instability begins to develop in the atmosphere.

Below is the most recent image from the 12z GFS image.

Based on this image, some instability will be in a formation that appears suitable for a squall line. At this time, The Weather Centre is not very concerned with this severe weather event, but we will definitely watch this situation.

CAPE

CAPE is a measure of instability in the atmosphere. When levels go above 2000 j/kg, it is a sign of developing instability in the atmosphere. Below is the latest image in the 12z GFS.

CAPE values also show the prospect of a fairly weak squall line that may begin to dissipate as it moves east.

HUMIDITY

Humidity can play a big factor in the severe thunderstorm. Humidity is supplied by the Gulf of Mexico. The image below details the humidity values expected in the air.

This image definitely shows fairly high values of humidity in the range of potential severe weather. The Weather Centre will issue a map on this potential outbreak.