The Climate Prediction Center released new 6-1o day, 8-14 day and 1 month outlooks on Thursday. Even though Flagstaff’s July precipitation is half of normal for this point in the month, the next month of the monsoon season should be above average. Below is an animation of these outlooks.
It’s been chilly an draining in most of Europe for the last few weeks. It’s been warm and dry for a couple of weeks in Northern Arizona. Thunderstorm activity will increase over the next few days and hopefully continue for most of the rest of the month. I think I mentioned July 19th in my last post. This should be right on time. It’s going to change for Northern Arizona, but I don’t think it will change for Europe.
The southwesterly flow on the monsoon season is returning to Arizona. It looks like a return to normal, but I’m not sure it will be enough. Currently, July is 0.58 inches below average for the month to date. It looks like Flagstaff will receive over an inch by the end of the month. This would leave us short of the normal roughly 2.5 inches.
With over 1.25 inches of rain since June 15, Flagstaff has enjoyed a strong start to the monsoon season. However, that will change. A series of strong, Eastern Pacific tropical storms far to the south are going to distract the moisture flow. These storms are not going to head northward along the coast. The current forecasts have them moving to the west-northwest almost due north of Hawaii before looping back towards Washington State. After today, the changes for rain drop substantially. Isolated thunderstorms will start this week. By next weekend and through July 19, the chances for precipitation drop to nearly zero.
The Climate Prediction Center published a new 1-month outlook on June 30. It shows most of Arizona with better than normal chances for above average July precipitation.
We all know that the 4th of July is the typical “start” of monsoon season in Northern Arizona. So, anything earlier in my mind is early. As I sit in Munich and enjoy an even thunderstorm and a cool (not cold) weißbier, the computer models are telling me it is going to start very wet.
From the Climate Prediction Center, Friday’s 6-10 and 8-14 day outlook are strongly on the side of a very wet start to the season. Personally, I don’t believe they have the best record on monsoon forecasts, but I hope they are correct. And that they are correct because they have improved their modeling capability.
Here is the total precipitation forecast from their GFS model for the next 10 days. Notice some areas are to receive as much as 2-3 inches of rain.
I still worry that a strong start will result in a quick season.
With the already wetter than normal June (over half an inch above average), the start of the monsoon season should be wetter and earlier than average. Yesterday’s rain in the Flagstaff area is just a taste. It should dry out one more time before next week. While the 1-4 week outlooks all call for above average precipitation, I’m not sure how long it will last with the on-coming La Nina.
Below are the outlooks for 6-10 days, 8-14 days and 3-4 weeks. They all show above average expectations of above average precipitation. After last winter’s dry conditions, this should help the Northland. As La Nina emerges, I am afraid that the season will start strong, but finish quickly and lead to a long dry phase.
I mentioned to a few people I saw in Flagstaff yesterday that I thought there was a chance the monsoon season would start in earnest next week. The warm/hot temperatures we will experience over the next few days will drive formation of the thermal low pressure system in southwestern Arizona. (Visit my Monsoon Mechanics website for more detail)
Watching the computer models, the monsoon flow from Mexico has come in and out of the outlooks. Yesterday, I thought that Wednesday or Thursday would kick of the season with some level of regular storms. Today, it doesn’t look so certain. In most years, the computer models poorly predict of the thunderstorm activity during monsoon season. I still think it will be a bit early. In any case, the typical 4th of July start looks certain.
Here is the newest 8-14 day precipitation outlook. Since it comes on a weekend day, I have doubts about its accuracy. But, it does point to an pre-4th of July start of monsoonal storms.
I’m still not sure I believe what is showing up in the computer models and forecasts. Although, it makes sense. It looks like a burst of monsoonal moisture is one its way for this weekend and next week. One week out, the forecast is calling for cooler, possibly below normal temperatures, and thunderstorms.
The current heat wave can generate the thermal low needed to kick-off the season. We’ll see.
To date, May has been chilly and wet. Flagstaff is ahead of average on precipitation by over an inch, and on temperature by 3.7 degrees. The average daily high has only by 62.2 degrees, which is 6 degrees below normal. I look at the month and maybe a bit deeper in this El Nino compared to others in the future.
The big news is that this week should not only bring normal, but beautiful sunshine and above average temperatures. These should be the warmest temperatures of the year so far. I think, the storm track has finally moved off to the north in the first step to the summer weather pattern. Now, the heat should start to build so that the monsoon low can develop later in June. This means strong winds should be less frequent, too.
As I sit in Hong Kong, I am wondering about the curious similarities in Flagstaff’s and Munich’s winter and spring. Both had relatively warm and dry winters. And now, both are having cold, wet Mays. With yesterday’s (I think that means Tuesday, jet lag and the international dateline make me wonder)…With yesterday’s precipitation, this May be came one of the 10 wettest May’s in since 1950. Only 8 times since 1950 has May been this wet. More importantly, at 1.52 inches, we are above 1 standard deviation from the norm.
Clearly, this is great for limiting the fire season in May. Last winter was dry, but still we are close to normal for the water year which starts September 1. Since January first, we are only 0.85 inches below normal. Not all that bad. Last winter should have been wetter, much wetter than normal because of the strong El Niño, right?
All too often, we learn that the more we know, the more we realize how much we don’t know. The National Weather Service is always careful to point out that El Niño conditions in the Pacific point to a general trend of warmer and wetter winters for Northern Arizona. This year we bucked the trend, and added on a cold wet May as the El Niño conditions literally evaporated in the Equatorial Pacific Ocean.
La Niña is uniformly predicted to follow. If you believe the experts, it could be one of the coldest La Niñas in quite a while. Next year should see a much cooler trend for a considerable part of the planet.
For the next few weeks, cool but drier conditions seem to be on the way for Northern Arizona. Don’t be surprised a significant freeze hits before the end of the month. I keep thinking that Munich or Flagstaff has had their last snow. Then, one or the other has one. When will winter end?
But, what about Tulips! We went to the Keukenhof in the Netherlands in the last few weeks. Our visit was the very definition of cold and wet. It snowed a bit while we were there. That kept the crowds down in the morning of our visit. Amazing!
I see these posts from people wishing for the end of winter on Facebook after the recent bit of snow. It is only April. We’re expecting snow next week in Munich. It looks like you shouldn’t put your snow shovel away in Flagstaff, either. The 6-10 and 8-14 day outlooks from the Climate Prediction Center have two things in common. Both are cold. Both are wet. The colors really speak for themselves. The computer models are indicating significant snow fall. Both time ranges are still far in the future, so we will have to wait.