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.
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.
At the end of last week, the outlooks for April shifted. I couldn’t bring myself to post about a change to upcoming wetter conditions on April Fool’s Day. The last 6 month’s we have seen a repeated disappearing act of storms. They would show up in the computer models as strong storms over a week away. Then they would slowly disappear into sunshine and warm conditions. Sigh.
So, here we are again. Two storms are over the horizon. One should arrive towards the end of next week. The second is about a week out. An animation of the 6-10 day, 8-14 day and one month outlooks is below. Each storm looks strong. It only takes a few to fill-in a precipitation deficit. Average April precipitation since 1950 is about 2 inches. The computer models snow just over two inches in the next two weeks.
We will see. This would help delay the fire season.
The computer models keep dropping a significant storm into the long-range forecast. If you look at the image from my last post, it shows significant precipitation around March 4, 2016. The forecasts do point to some precipitation this weekend, but not the large amount in that image. The problem is that the big storm is always just over the horizon. Below is the outlook for Monday, March 14. It’s almost identical to the image in my last post.
As we move away from a very warm and dry February, we have to wonder if March will fulfill its historic reputation for the wettest time of year. The computer models keep pointing to a change in the storm track that will push storms over Arizona. We will see. Not much to blog about when it’s sunny and warm.
Warm and dry has become the February story. The wet cold start has faded into sun and occasional high winds. There have be a few times the outlook was positive for wet conditions. It hasn’t happened.
Is it unusual for February to be dry during an El Niño winter. I think the data are pretty messy and there really isn’t enough to be very meaningful. Since 1950, the average for February precipitation in Flagstaff is about 2 inches. There are very wet and fairly dry Februaries during El Niño years.
Most of the areas that normally benefit from El Niños are benefiting this year. We continue to be way ahead on 12 and 24 month total precipitation.
The GFS model shows a possible weak storm at the end of the month, and a stronger storm at the start of March.
The 3 month outlook from the Climate Prediction Center continues to look positive from a precipitation point of view.
There is still time left this winter for more snow. March is typically the wettest month of the year. I think more is on the way.
Thanks to an Eastern Pacific hurricane and very strong northerly storm track, the next couple weeks will be very dry in Arizona.
I keep looking at the longer range forecasts, the GFS computer model and the Climate Prediction Center outlooks. It seems like the 6-10 day outlooks have a huge amount of variability. Last weeks snow was never clearly in any of them. One day the 6-10 would be dry. The next day it would be wet. Nothing solid. Yesterday everything had next weekend looking very wet. Today, Thanksgiving weekend looks dry.
I bet it is harder to run the models with the current conditions. There isn’t a great analog available between the Blob, El Nino and the very cold North Atlantic. So, hang on, it could be a rough ride with unexpected storms and dry periods.
The 3-month outlook from the Climate Prediction Center seems to have Flagstaff in the greater than 50% chance of above average precipitation. Southern Arizona could be even wetter.
And now, news from Munich, DE. We had our first snow on Saturday night. No real accumulation. We had an early dinner, then we went to an organ concert at Saint Peter’s Church near Marienplatz. When we came outside, huge flakes were falling. We walked across Marienplatz and went up to the Café Glockenspiel and watched the snow fall as we had dessert. It was beautiful.
The Christbaum on Marienplatz isn’t very healthy. It had a very dry summer that weakened it. It will be hard for it to make it through Christmas. The needles are falling off.
It’s been a while since my last post. This is all thanks to Apple. I bought a new laptop because using my big MAC in Germany isn’t practical anymore. We just don’t have the room for it. After a week of using the new laptop, the arrow keys broke. The first chance I had, I took it to the Apple Store to have it replaced or fixed. They wanted to fix it, but the part would take some time. I could still use the computer, but not easily. Then I took it back when the part came in. They said I would receive a message in 3-5 days. After a week I called. They told me it would be another week before they got to it. Sheesh. I feel like just gave Apple a loan of over a thousand bucks for a month! This is not Steve Jobs’ Apple!
Deep cleansing breath in…and out.
So, I missed blogging about the rain last week. With the airport receiving 1.27 inches of rain, Flagstaff is well on its way to an above average rainfall month. The average October precipitation in Flagstaff since 1950 is 1.54 inches. With the outlooks for the next few weeks, we should easily surpass the average.
I’ve taken the current 6-10 day, 8-14 day, 3-4 week, 1 month and 3 month outlooks and made an animated gif. This is below.Most of Arizona is comfortably inside the above normal chances for above average rainfall for all time periods. El Nino and the disappearance of the Ridiculously Resilient Ridge are driving this. I wonder when the first big snow will show up. It could be this month.
Also, the North Atlantic is colder than normal. This can also mean a wetter than normal winter. I plan to do some more on this topic when I get my laptop back. The spreadsheets are on the laptop.
In the last two months, the Climate Prediction Center has not been very accurate with their 1-month precipitation outlooks. July and August precipitation amounts were close to average. September’s precipitation amount is running well below average. On the other hand, they we right about April, May and June. The long-range outlooks continue to show a strong, El Niño winter.
They have now released an Experimental 3-4 week Outlook. This was a gap in their forecasting portfolio. On their home page, They had outlooks for 6-10 days, 8-14 days, 1 month, 3 months, Hazards and Drought. Below is the current 3-4 week precipitation outlook.
Looks very wet. However, in their discussion they state:
Following ensemble prediction system forecasts from the CFS, ECMWF and JMA, the forecast for the week 3 and 4 period favors above-median precipitation for the Southwest region extending eastward across Texas into parts of Louisiana. This is somewhat consistent with statistical forecasts based on El Niño, however this tool does not appear to have great skill for precipitation forecasts under El Niño conditions at this time of year, indicating the probable influence of additional climate variability on the precipitation pattern.
So, we will have to wait and see. I think late September through November are the toughest months for forecasting Northern Arizona’s weather.
It appears the Ridiculously Resilient Ridge and the related Pacific Blob are going away. Deep details are at The California Weather Blog. The Ridge created the Blob, which reinforced the Ridge, which reinforced the blob, and so on. The ridge is breaking down. The Blob should also disappear over the winter. This is very good news for California and may help reinforce a strong El Niño winter for Arizona.
One last thought, the Atlantic Multidecadal Oscillation is continuing to look like it has shifted. This could be a strong long-term signal for wetter conditions in Arizona.
I think I mentioned several times last summer NOAA’s GFS model predictions of the monsoon season impressed me.They seemed remarkable accurate. I say seemed, because I don’t think I ever did or saw any statistical analysis to prove it. We will see how they do this year.
For now, the model has the season walking slowly up to the season. If you remember last summer it started in earnest. This year, I think we will start to some thunderstorm action at the end of this week, but probably not the real start until closer to the 4th of July. This is normal.
The current El Nino conditions and the warm blob off the coast of California continue to cause me some concern. The image below is the most recent global sea surface anomaly picture from NOAA. There is plenty of warm water to generate the moisture needed for a strong monsoon season. I still worry that jet stream winds might not cooperate One of the reasons there are few strong Atlantic hurricanes in El Nino conditions is due to the high level winds that shear the tops of the clouds off as storms develop in the Atlantic or the Gulf of Mexico. Could these winds impede our monsoon season?
I don’t know. Also, I don’t think there is any clear data on any effect from El Ninos on monsoon precipitation. We will have to wait and see. For now, enjoy summer. The warm temperatures may not last long.