SEVERE WX THREAT Sunday: Could be widespread wind damage...

[WXBUFFJIM]

Good afternoon everyone. While wintry weather is one big topic regarding this weekend's storm system, a second topic will be severe weather. Severe weather could potentially be widespread with widespread damaging wind being the main threat later in the day on Sunday.

http://www.spc.noaa.gov/products/outlook/day3otlk.html shows the day 3 outlook from the storm prediction center in Norman, Oklahoma. Severe weather threat exists from lower Michigan southward into Missouri, Illinois, Arkansas, and even down into places that does not need severe weather, east Texas, Louisiana and even Alabama once again. A digging upper trough will shift eastward from the central Rockies eastward into the Middle Mississppi Valley through the day on Sunday. A 120 knot mid level jet will be in place along with the system becoming negatively tilted. The events described above combined with the huge thermal or temperature gradient will hence intensify the surface low pressure area. As the low pressure moves rapidly from the central plains to the northern Great Lakes region through the day Sunday, the trailing cold front will accelerate eastward as well. Colder drier air behind the cold front will combine with warm moist air ahead of the front. That combined with some instability and very strong dynamic forcing aloft will enhance the severe weather potential. The main severe weather mode will be damaging winds as most of the storms will form into a big squall line. Some lightning is possible, but many of the storms will be low topped. It will not take much thunderstorm activity to enhance the downward transfer of the winds because winds aloft, even 5000 feet above the ground will be above severe criteria. 120 knot mid level jet, even higher winds in the upper levels. Certainly this all points to a widespread very damaging wind event Sunday afternoon into Sunday night.

Cities in the path of this severe weather threat include Quad Cities, Chicago, Green Bay, St Louis, Little Rock, Memphis, New Orleans, Houston, Beaumont, and Jackson as well. All persons in and around this area should prepare to seek shelter on the lowest floor of their home or business if a severe thunderstorm or tornado warning is issued. Widespread damaging winds are a possibility and can be as damaging if not even more damaging than an actual tornado because damaging straightline winds have a bigger width than tornadoes do. Preparations are not a bad idea also just in case widespread severe weather becomes a more immient threat.

Stay tuned.

Jim

[JCT777]

That is a situation that does indeed have to be watched. It is rare to get severe weather that far north (Chicago, Wisconsin, lower MI) in late November, but the setup with this storm makes it possible.

[pawlee]

BRUTHA... I AM THAYRE!!!! p

[Dan]

I wouldn't be suprised if the Mississippi Valley eastward to the Appalachians get another decent rainfall out of this next system. Not as much as the last storm, but still a decent rainfall. An inch or two of rain dosen't sound like a lot, but Flash Flood Guidance is very low from the Tennessee Valley into the Southern and Central Appalachians.

[CaptinCrunch]

Forecast for the Dallas/Ft. Worth area calls for a slight chance of showers and Thunderstorms Saturday night and Sunday, only about 20%. Highs Sunday in the lower 60's to upper 50's and low's in the mid 30's. Monday calls for partly cloudy skies with high's in the lower 50's and lows in the lower 30's.

[Mr Bob]

This will be moving a lot faster and the main dynamics will be lifting rapidly northward unlike the last trough which dug very far south....Mississippi Valley does well but just west of Apps into the Mid Atlantic will not do as well this time....given the current model trends. Would be surprised to see a third of last weeks totals...

[Colin]

Thanks for the analysis, Jim...this will have to be watched for sure.

[JCT777]

Agreed, Mr. Bob. From the Apps east this will IMO be garden-variety showers late Monday into early Tuesday.

[ColdFront77]

Here is forecast from this late afternoon and evening for central and north-central Florida...


Sumter county, FL forecast issued at 8:45 pm EST

Monday. Partly cloudy with a 30 percent chance of showers and thunderstorms. Highs in the mid 70s.

Tuesday. Partly cloudy. Slight chance of showers and thunderstorms. Lows around 50. Highs around 70.


Marion county, FL forecast issued at 5:00 pm EST

Monday. Partly cloudy with a 20 percent chance of showers and thunderstorms. Highs in the mid 70s.

Northern Lake county, FL Forecast issued at 4:00 pm EST

Monday. Partly cloudy then becoming mostly cloudy. Slight chance of showers and thunderstorms in the
evening. Highs in the upper 70s. Chance of rain 20 percent.