Good afternoon NBC Action Weather Bloggers,
Watch NBC Action News for Kansas City's most accurate forecast (5 years in a row) tonight at 5, 6, and 10 PM as this storm approaches us this weekend. And, don't forget our new weekend morning news at 8 AM Saturday & Sunday!
Are you excited yet? Do you think you will be let down again? There is no way the entire viewing area will have accumulations of snow, which means someone will get no accumulation out of this storm. And, others could end up over 6 inches of snow by Sunday afternoon. Who will be in the heaviest band? Could the rainfall be enough to cause significant flooding? Is there any chance of freezing rain, sleet, a mixture? What about thunderstorms? These are just some of the questions that we have to try to answer in the next 36 hours as this very potent storm approaches our area.
Look below at the watervapor satellite photo from late this morning. The storm is now looking impressive, spinning over Arizona. It has a lot of Pacific moisture already surging our way:
This storm, that you can see over Arizona right now, is forecast to eject out across Missouri on Sunday. It will move fast, but if you get into the comma head of this storm it will last into early Sunday afternoon. Trying to find out where this deformation zone is going to set up is one of the biggest forecast challenges we face again. And, the storm has some cold air with it, but it won't become a significant snowstorm until a shot of colder/drier air gets pulled into the storm early Sunday morning. Below you can see the forecast from this mornings NAM model valid at 6 AM Sunday. I pointed to the 540 thickness lines. One surge of cold air is about to explode southward as the storm ejects. And, there is just enough cold air aloft with the storm itself. These will phase together and become a huge Wisconsin, northern Illinois snowstorm late Sunday. We are in the developing area and it poses a big problem for weather forecasters. How fast will this cold air get here. And, it will depend on the track of the storm as it ejects, which is anything but certain at this time.
The two precipitation forecasts from the GFS model are shown below. The first one shows the wet potential for this storm. The ground is already saturated from our wet winter and frozen ground. So, it will not take much to produce significant flooding. 1 to 2 inches of rain and there will be flooding. Any more than 2 inches will begin creating some serious flooding. This is another thing we will be monitoring. Again, the track of the Arizona storm is crucial. If it goes a bit farther south the rainfall pattern shown below will shift with it.
This last map below is the precipitation forecast from the GFS model for the 12 hours of 6 AM to 6 PM Sunday. This would mostly be snow. On this model that is not a lot for Kansas City, so don't get too excited yet. However, the NAM has a much wetter solution. We may be in between the two solutions. The dark green is 1/4 inch liquid. The second shade, over KC is only 1/10th inch liquid.
The rain should move in late Saturday. If you are tracking this storm, one key and very important indicator of the storm coming out farther north will be late Saturday. If the rain shield moves in early, then the storm is very likely a bit farther north. As of early this afternoon we believe it will begin late Saturday afternoon with a cold rain. Thunderstorms are possible. The rain would changeover to snow early Sunday morning, and be over by 3 PM Sunday. There will be a huge difference in snowfall totals depending on whether it lasts for 1 hour or 6 hours? We just don't know yet. And, another factor we must pay close attention to is the surface temperature. Is there any chance of freezing rain as the rain moves in Saturday night?
We will have extensive details on our newscasts tonight. After the new data comes out, our 10 PM show will be our most confident one! Let us know which questions you want us to answer on the air.
Have a great FRIDAY!
Gary