Thanksgiving storm update - 11/24/15

On Saturday I had an extensive post about last weeks severe weather and an outlook for the "Thanksgiving" storm.  You can read that long post here.  At the end of that post I discussed the upcoming storm.

In that previous post I showed a satellite image with  three features that were going to impact the plains weather.  The first was a low pressure system aloft (labeled L on the previous satellite image) and talked about how it would weaken as it moved south and then east and eventually into the plains.  Today that system had reached the southern Rockies and as expected was contributing to bringing Gulf Of Mexico moisture northward.  This moisture will translate into low clouds, some fog and drizzle later Tuesday night and Wednesday across a large part of Texas, Oklahoma and eastern Kansas.

Here is the latest satellite image as of Tuesday afternoon...(edit on image below - Sandra, not Rick)

Referring back to the satellite image I showed on Saturday....The original "L" is now the "X" over southern Colorado.  The original X1 is now the strong Low off the NW Coast.  The original X2 has moved to north of Hawaii but will likely still be a play maker for the plains (more on that at the end of the post).


More importantly is the storm, the one off the NW coast.  Again, in the previous post I showed the X with the superscript 1 on the satellite image.  At the time it was just a disturbance but as advertised it has since amplified into a power upper storm just off the Washington coast.  It will continue to drop south and become a big upper low over the Great Basin.  The strong jest stream on the west side will eventually translate around and lift out across the plains Wednesday night and Thursday.  The result will be a strong cold front dropping south into the plains and copious amounts of precipitation developing across the region.

The six million dollar question is just in what form will the precipitation fall.  The upper low has not been fully sampled yet by the National Weather Service observation  program as the storm was still off the coast.  But it has become increasing apparent that there will be mixture of precipitation as there will likely be a warm layer aloft with the storm.  The best guess, keeping in mind the limited sampling in the upper parts of the atmosphere, is the following for Thanksgiving Day and Friday...

The freezing precipitation will likely transition from west to east and this map illustrates perhaps the farthest east.  In other words, it will start as rain in areas like Amarillo, Dodge City, Wichita, Topeka, KC, Lincoln (etc.) and then flip to freezing precipitation later Thanksgiving or Friday.  It should remain all liquid across SE KS and most of Oklahoma.

What's my confidence?  Not that high, at least initially.

Snow amounts?  You're going to here everything because the media likes to use computer forecasting models that sometimes just are not capable of modeling the true atmosphere.  I've already heard 6 to 8 inches for Dodge City, yet there is a strong possibility that it may not even flip to snow until late in the storm.  What I'm saying is that it is WAY TOO EARLY to discuss amounts of snow and exactly where the snow will fall.

Here's the kicker....what about the X2 out in the Pacific?  Chances are pretty high that the upper low that forms out west may sit there for a number of days.  Eventually the X2 system will be ingested into the Great Basin storm and will be "kicked out" across the plains.  The most likely time for this will be late in the weekend.  It too should bring additional precipitation and I'm guessing the frozen line will be a bit farther south and east, but details are highly uncertain, if not impossible to say for sure.

Finally, what about Tropical Storm Rick Sandra that is in the bottom of the satellite image?  It will likely become a hurricane as it turns north.  Eventually the remnants will track  northeast and perhaps into Texas and the lower Mississippi Valley.  That will definitely have to be watched as there is a scenario that it would bring extensive flooding rains to that part of the country.  It's not entirely out the question that those remnants could be even farther north!  It'll have to be watched!

The Weather Prediction Center has the following outlook for precipitation through Sunday.   Impressive for anytime of the year, let alone the last part of November!

 
Stay informed by monitoring NWS forecasts at weather.gov.  If you're going to be on the road later this week and weekend, you can go to each states road reports web page.  A quick map to each state's DOT can be found here.

In Kansas you can go to: http://kandrive.org/kandrive/roads/#conditions/-98.41/38.3957/7 

I will not be able to update this post until perhaps the weekend.