Severe Weather Discussion for April 7 and 9-10, 2008.
– Active severe weather event is expected for much of Oklahoma through
the overnight hours. Primary threats are tornadoes, destructive hail,
and damaging winds.
– Significant severe weather event is possible across much of Texas on
Wednesday. In Oklahoma an excessive rain event is also likely.
– Chase Status is increased to Level 4.
Little change to prior forecast and reasoning. Many parameters are
in-place for an active severe weather for Oklahoma, except moisture.
Elevated moisture has been returning to the region the past few hours
and the surface appears to be catching up. With the clock at 1pm, 60F
dewpoints are close to the Red River. 12z models are in good
agreement that southwest Oklahoma is the prime spot for severe
weather. Storms are expected to initiate between 5-6pm and increase
during the overnight hours. The most significant threat may occur
between 7-9pm as the low level jet develops.
Upper system will pass over the area tonight and rapidly move
northeast away from the region by Tuesday afternoon. By early
Wednesday a large longwave trof will start developing in the western
U.S. In response to this feature, deep layer tropical moisture will
stream north across the region. A Canadian cold front is still
expected across Oklahoma and this will remain place through Wednesday
night. Models want to move this boundary north and I have doubts
about that issue. I think this is one event where we'll remain the
cold sector. This will also lead to widespread excessive rainfall
across the region. Models continue to show 3-5 inches for eastern
parts of Oklahoma.
12z NAM shows the warm front just south of I-20 and this looks
reasonable on Wednesday. Areas to the south will be in the warm
sector and face a significant severe weather threat during the
afternoon and evening hours. More details on Tuesday.
Risk area for any part of OK/TX (valid: 04/08 Day 2):
Level 4 – Heading to Lawton this afternoon.
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