Post by Zack Fradella on Nov 19, 2007 14:17:31 GMT -6
The long, dry, boring, sunny, warm, non-eventful, la nina type pattern is about to come to a close.
The sucky part?
We are going to go from one extreme to another. Instead of sunny, warm days; we are going to see cold, wet days.
It all begins on Tuesday when a strong jet max rotates around the southern side of the Aleutian Low. This will pump a large ridge into NW Canada, allowing for the pattern to amplify downstream in the US Plains. What this all means is the cold air from Canada will be taking a trip south for the Thanksgiving Holiday.
Our weather begins to go downhill on Wednesday when a strong cold front will be plowing towards the Gulf Coast. The bulk of the precipitation should stay well north of our area as the best lift drives into the Ohio Valley. However, any precipitation that does fall will most likely be Wednesday Night into Thanksgiving Morning. It should be noted that some of the storms associated with the cold front could be strong to severe with damaging winds and maybe an isolated tornado.
Now we get into the tricky part of the forecast. The first trick will be timing the frontal passage as some models differ in their solutions. The GFS looks to bring the front through around 9AM Thanksgiving Morning, the EURO around 8AM, and the NAM around 6AM. Since models usually are too slow with canadian fronts, I will go with a 6AM pass Northshore/8AM pass Southshore. The second trick is forecasting temperature falls on Thanksgiving Day. If you are a warm air lover run outside around 6-7AM, and you will be around a toasty 70 degrees. Cold air lovers should sleep in till about 9AM when the temperatures will falling from the 60's into the 50's. As with any frontal passage expect winds to go up to about 15-25mph making temperatures feel even colder.
Thanksgiving Day Temp Timeline
6AM---------70F
9AM---------63F Windy, Cloudy
Noon--------58F Windy, Mostly Sunny
3PM---------56F Windy, Mostly Sunny
8PM---------45F Northshore/ 50F Southshore Windy, Clear
In my opinion, Friday should be a perfect day for Christmas shopping as long as you bundle-up. Morning temperatures will range from the 30's Northshore to the 40's Southshore. Expect the winds to continue to be between 10-20mph. High temperatures will top out in the lower 50's, which is all dependent on cloud cover. We could easily stay in the 40's for highs if clouds remain in place, but I feel we should see a few peaks of sun to bump us into the lower 50's.
The Weekend Mess
The weekend will be a whole different ballgame as a vort max slides down the backside of the Central US trough. This vorticity maximum will either cut-off a low in Northern Mexico, or just progress Eastward as a phased system. This is where things get downright impossible to forecast. One thing that is for sure is an area of low pressure will develop in the Gulf of Mexico in response to this approaching upper trough. Another for sure thing is Saturday and Sunday will be ugly.
Where does this low form? How does it track?
Those two questions determine our weather from Saturday afternoon until Sunday night. A low tracking South of our coastline would mean a cold and rainy Saturday/Sunday. A low tracking right over SE La would mean huge temperature differences from Northshore to Southshore, which is basically impossible to pinpoint at this time. Also, a low tracking to our North would spell for a dangerous severe weather threat and warmer conditions.
The sucky part?
We are going to go from one extreme to another. Instead of sunny, warm days; we are going to see cold, wet days.
It all begins on Tuesday when a strong jet max rotates around the southern side of the Aleutian Low. This will pump a large ridge into NW Canada, allowing for the pattern to amplify downstream in the US Plains. What this all means is the cold air from Canada will be taking a trip south for the Thanksgiving Holiday.
Our weather begins to go downhill on Wednesday when a strong cold front will be plowing towards the Gulf Coast. The bulk of the precipitation should stay well north of our area as the best lift drives into the Ohio Valley. However, any precipitation that does fall will most likely be Wednesday Night into Thanksgiving Morning. It should be noted that some of the storms associated with the cold front could be strong to severe with damaging winds and maybe an isolated tornado.
Now we get into the tricky part of the forecast. The first trick will be timing the frontal passage as some models differ in their solutions. The GFS looks to bring the front through around 9AM Thanksgiving Morning, the EURO around 8AM, and the NAM around 6AM. Since models usually are too slow with canadian fronts, I will go with a 6AM pass Northshore/8AM pass Southshore. The second trick is forecasting temperature falls on Thanksgiving Day. If you are a warm air lover run outside around 6-7AM, and you will be around a toasty 70 degrees. Cold air lovers should sleep in till about 9AM when the temperatures will falling from the 60's into the 50's. As with any frontal passage expect winds to go up to about 15-25mph making temperatures feel even colder.
Thanksgiving Day Temp Timeline
6AM---------70F
9AM---------63F Windy, Cloudy
Noon--------58F Windy, Mostly Sunny
3PM---------56F Windy, Mostly Sunny
8PM---------45F Northshore/ 50F Southshore Windy, Clear
In my opinion, Friday should be a perfect day for Christmas shopping as long as you bundle-up. Morning temperatures will range from the 30's Northshore to the 40's Southshore. Expect the winds to continue to be between 10-20mph. High temperatures will top out in the lower 50's, which is all dependent on cloud cover. We could easily stay in the 40's for highs if clouds remain in place, but I feel we should see a few peaks of sun to bump us into the lower 50's.
The Weekend Mess
The weekend will be a whole different ballgame as a vort max slides down the backside of the Central US trough. This vorticity maximum will either cut-off a low in Northern Mexico, or just progress Eastward as a phased system. This is where things get downright impossible to forecast. One thing that is for sure is an area of low pressure will develop in the Gulf of Mexico in response to this approaching upper trough. Another for sure thing is Saturday and Sunday will be ugly.
Where does this low form? How does it track?
Those two questions determine our weather from Saturday afternoon until Sunday night. A low tracking South of our coastline would mean a cold and rainy Saturday/Sunday. A low tracking right over SE La would mean huge temperature differences from Northshore to Southshore, which is basically impossible to pinpoint at this time. Also, a low tracking to our North would spell for a dangerous severe weather threat and warmer conditions.