KNAU and Arizona News
Fri May 10, 2013
Rain! KNAU Meteorologist Lee Born Talks Weather
This week's rain storms brought the first precipitation in weeks to northern Arizona. KNAU's Gillian Ferris Kohl talks with meteorologist Lee Born about the rain and the summer weather forecast.
GFK: Finally! Some rain.
LB: Yeah, it has been a while. It's been a few weeks since we've seen any precipitation. But, April was super dry, it was the 10th driest April in 115 years since record keeping began. And we had very little moisture, less than 1/10" April. And, in fact, you have to go all the way back to March the 9th to find more than a tenth of an inch of precipitation here in Flagstaff. So when we got some rain this week, that was the first time in almost 2 months that we saw over a tenth of an inch of precipitation. So, it's dry around here to say the least.
GFK: Where do we stand right now for precipitation compared to previous years?
LB: In 2013, right now we're at 68% of normal. If we go all the way back to September 1st, it was a dry fall back in 2012 and this dry spring hasn't helped much and we're at 9 1/2" when we should be up around 16 1/2". Dry, for sure. You know, 2012 was also a very dry year, I think it was the 14th driest calendar year, somewhere in there.
GFK: I was pleasantly surprised by the thunder and lightning a couple of nights ago. And I'm curious if there's a difference in character between spring thunderstorms and summer thunderstorms.
LB: It's always fun to have the thunder and lightning around here, for sure. And fortunately, it was accompanied by a little bit of moisture because often times this time of year we get the dry lightning which isn't good. What we have right now is this area of cut-off low pressure. It's in the upper levels of the atmosphere. It's a big spinning pool of cold air in the upper levels of the atmosphere, really cold! Like, if you look at the balloon launches that they put out from the National Weather Service, it gives us a profile of the atmosphere. You don't have to go up but several thousand feet and the temperature is already at zero degrees. And that's what we call an unstable atmosphere. And so, when these warm air bubbles are rising, they keep rising until they cool and condense and make showers, and sometimes, in this case, some thunderstorms as well. And similar to what we see during the monsoon; we don't have quite the moisture that we have during the monsoon when we get that tropical air in here. But, this storm when it came in earlier in the week, also brought a little bit of tropical moisture with it and just enough to kick off some fairly light showers around the region.
GFK: What's monsoon season looking like this year? What's the prediction?
LB: Well, unfortunately Gillian, there is no real long-term forecast on monsoon like we have on winter outlooks. It's not really based on what the ocean temperatures are doing and El Nino and La Nina. The monsoon always seems to come usually on time; some years better than others. But there's really not a lot of indicators as to what makes for a strong monsoon or a lesser monsoon season. So unfortunately, we really can't say whether it's going to be a good one or a bad one. But we WILL have one.
GFK: What's our weekend weather looking like, Lee?
LB: Warmer. Drier. And the storm system will be out of here by Saturday, but there'll be enough lingering moisture for a partly cloudy day, I think. A bit warmer, temperatures will jump up here and I think we'll be close to 70 on Saturday. And on Sunday, most of the moisture will have moved out and we'll be seeing some 70 degree temperatures here in Flagstaff and much drier, sunny weather across the region.
Lee Born is KNAU's in-house meteorologist, based in Flagstaff.