Sunday, February 18, 2007
LATE WEEK SEVERE STORM POTENTIAL
As talked about in the previous entry, the system that was at the time off the coast of Japan has now moved across about half of the Pacific Ocean. It is showing up nicely on satellite imagery just south of the Aleutians and long range global forecasting models still are developing quite an intense surface low just east of the Rockies by Thursday as this trough transverses across the country.
This storm will have a lot of jet energy to work with, not only aloft but in lower levels too. A 50kt + low level jet at 850mb (5000ft.) has been successively proged around the Friday eve. time frame. These winds are more or less out of the due south, whereas winds at 300mb are out of the west south west. A jetstreak looks to pass through the base of the trough close to the Friday eve / Saturday morning period and this will further deepen the trough and strengthen the low. Winds within have been advertised as high as 130kt. This directional shear, or turning of winds with height will likely aid in the development of some strong to severe thunderstorms.
Moisture at this point looks to be available as most of the week ahead we will have southerly and south westerly winds. Lapse rates look to be descent too with a lot of cold air wrapping in aloft of this system and it looks as if there are several waves within the flow in addition to the associated cold front to initiate convection.
Time frame wise, the one year anniversary of the March 12, 2006 tornado is just around the corner and historically, big weather events have happened in our area over the month of February. We will continue to monitor developments with this storm system.
Keep it tuned to 4029 we’ll keep you advised both on-air and on the web!
This storm will have a lot of jet energy to work with, not only aloft but in lower levels too. A 50kt + low level jet at 850mb (5000ft.) has been successively proged around the Friday eve. time frame. These winds are more or less out of the due south, whereas winds at 300mb are out of the west south west. A jetstreak looks to pass through the base of the trough close to the Friday eve / Saturday morning period and this will further deepen the trough and strengthen the low. Winds within have been advertised as high as 130kt. This directional shear, or turning of winds with height will likely aid in the development of some strong to severe thunderstorms.
Moisture at this point looks to be available as most of the week ahead we will have southerly and south westerly winds. Lapse rates look to be descent too with a lot of cold air wrapping in aloft of this system and it looks as if there are several waves within the flow in addition to the associated cold front to initiate convection.
Time frame wise, the one year anniversary of the March 12, 2006 tornado is just around the corner and historically, big weather events have happened in our area over the month of February. We will continue to monitor developments with this storm system.
Keep it tuned to 4029 we’ll keep you advised both on-air and on the web!
Posted by Ted Zarras at 5:31 PM
1 Comments:
Ted it's interesting to note that most of the 2006 tornadoes in Arkansas happened in the month of March...
Welcome to severe weather awareness week across Arkansas. Now is the time to talk to your family about severe weather safety!
The GFS continues to paint an impressive severe weather story for Saturday. I'm thinking we'll likely have a strong cap to deal with on Friday due to the south to southwesterly winds aloft; however, an active low level jet may support elevated hail producing storms late Friday night into Saturday morning, but the big storms will hold off until Saturday evening. By Saturday afternoon, a dry line across central Oklahoma will likely erupt as a jetstreak erodes away the cap. Severe storms will race our way for Saturday evening, and the wind shear will likely support rotating storm cells capable of large hail and possible tornadoes.
I know the CAPE numbers are unimpressive at this point, but don't let that fool you. We'll probably have some gulf stratus to work with, and the models have a hard time handling that aspect. With the strength of the winds aloft, we'll mix out and see sunshine by Saturday afternoon. I have seen CAPE values jump from 500 to 3000 in a matter of a few hours, especially if a dry slot develops ahead of the dry line. We'll be watching it...great job Ted on keeping everybody informed!
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