Severe Weather Discussion for May 6 – May 8, 2007.
– Active severe weather day for Oklahoma and Kansas. Primary threats are destructive hail, tornadoes, and damaging winds.
– Severe thunderstorms will occur across parts of Texas/Oklahoma on Monday and Tuesday. Generally, primary threats are large hail and damaging winds, there will be a localized enhanced area for tornadoes. At this point the tornado threat area is difficult to pinpoint.
– Excessive rainfall will pose a flooding threat for parts of the region. Tough to pinpoint this area, but much of the area has decreasing FFG values and this threat will be monitored.
Very amplified flow continues across the U.S. today as a longwave ridge is over the eastern U.S. with a closed and cutoff low across the SW U.S. The result is meridional flow across the region from 500mb to 200mb. Lack of frontal intrusions into the region continues to allow deep layer tropical moisture to flow north, resulting in dewpoints well above normal in the upper 60s/low 70s. As such, morning CAPE values are around 3000 J/Kg. CAPE values will only increase throughout the day as moisture continues to advect north and temperatures warm. A line of storms is ongoing in northwest Oklahoma and this will produce outflow boundaries across this part of the region. With a weakening cap, severe thunderstorms are expected to develop during the next few hours across parts of the region. A tornado watch is up for western and central Oklahoma. Any isolated storms will have high supercell potential and attendant tornado threat.
The threat tomorrow should be lessened by activity today, but there will still be a severe weather threat. On Monday, the threat appears to shift south and puts Texas in the better chance.
Upper system will move very little through Tuesday as the longwave ridge remains in-place to the east. As such, flooding will be possible due to frequent rainfall. Flash Flood Guidance values are low in some areas due to above normal rainfall this spring.
Risk area for any part of OK/TX (valid: 05/07 Day 1, Day 2):
– Slight: 100%, 100%
– Moderate: 75%, 40%
– High: 0%, 0%
Level 3 – Monitoring, but probably can't go.
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