Tuesday, April 18, 2017

Tricky Weekend Forecast

When forecasting, you look at things that you are confident about and things that are still questionable. I'm very confident that it will rain this weekend. I'm confident that many people will see an inch or so of rainfall. I'm confident that a few areas may even see 2.00" of rainfall. I could easily go on TV tonight and say "It's going to rain this weekend" and I'd likely be right. But, we all demand more in a forecast, so we try to nail down the timing and if there will be severe weather. For the weekend, models are NOT in agreement on timing or the track of the low. The TRACK of the low determines the temperatures and just how unstable we will get in Region 8. Model 1 (GFS) has the low tracking NORTH of Region 8 Saturday afternoon. This would leave us with the threat of severe weather on Saturday afternoon and evening. Model 2 (Euro) has the low moving farther south about 12 hours sooner. Click image to enlarge:
As I mentioned, the TRACK of the low determines a lot. This is a comparison of CAPE below. CAPE is the fuel needed for storms. These images are 12 hours apart when the CAPE is most concerning for each model. For model 2 (Euro), I would very little worry about severe weather, if it verified (actually happened). I WOULD be concerned with the setup from Model 1 (GFS). Click image to enlarge:

To summarize:

  • I'm VERY confident it will rain on Saturday.
  • I'm VERY confident that a 1.00" rainfall will be common.
  • Severe threat is still questionable.
  • Timing is still questionable.
  • Stay tuned for updates, we are still a few days out.
Have a great day!

1 comment:

kaw said...

How does Friday look, particularly in the morning and early afternoon?