Tuesday, February 20, 2018

Rainy Pattern Begins: Round 1

As we have talked about for several days, a rainy pattern starts today. I'm going to ONLY talk about this first round of rainfall in this post. There are several maps floating around showing the 7 day rainfall totals. While those maps have impressive numbers, we need to take each round separately so that we don't start building arks! Here are my thoughts as of right now regarding the rain tonight and tomorrow, Round 1:
  • Rain has already started in some parts of Region 8.
  • It will likely rain ALL DAY on Wednesday.
  • On average, 2-3" of rain is likely across all of Region 8 before Thursday.
  • The precipitation RATES will not be that high, so "flash" flooding is not likely. Flooding is possible.
  • I would be shocked to see anyone get more than 0.50" in a 1 hour period.
  • This is a prolonged rain event. It will not all come at once.
  • We get a little break on Thursday (Scattered Stuff) with Round 2 coming Friday.
So, let's dig into the data. As I mentioned, while rainfall looks impressive, it does not look like the rain intensity will stay high through the entire event. Sure, we may have some brief downpours, but most of the rain is going to be light to moderate. I do not anticipate anyone seeing more than 0.50" in a 1 hour period at any given time. If so, it should be isolated. Models are in general agreement for Round 1, with most showing 2-3" of rain. There are some model runs showing less than 2" in spots AND there are some model run showing more than 4" in spots. These would be extremes. Average is 2-3". Here are four models showing the rainfall totals for tonight and Wednesday:
Now, let's talk about timing. At midnight tonight, the rain is increasing in our western counties. If you are traveling OUTSIDE of Region 8 to the NW, notice the freezing rain:
By morning, everyone is wet:

The rain lingers around ALL DAY, and it will still be raining at 6PM:
Stay tuned for any changes! We will keep you updated on new data with the Region 8 Weather App!


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