| Yes and no. Yes, it is a season not a single storm. Tucson NWS is Monsoon Headquarters and they had criteria for determining when the Monsoon started and stopped but it was felt that these were too complicated for Americans so they changed to a calendar start and stop time which works well. |
| The starting point for understanding the NAM or pretty much anything in Meteorology is to think about the time of the year. In the winter, the prevailing westerlies and the jet stream dominate weather in the CONUS. In the summer they still have an impact but other mechanisms can come into play. No time in this article to explain it but the ITCZ moves to the north.
I would like to add that the differential heading of land and water in Mexico causes moist air to rise creating thermal low which kind of shoves the high north of it to the north. The mountains also play a role in sometimes blocking air flows and uplifting air masses which causes precipitation. It is quite complex but we are going to simplify it a bit in this article. |
| This map shows the percentage of annual precipitation that arrives during the Monsoon Season. You can see that the NAM is very important to Arizona, New Mexico, Kansas, Western Texas, and the small part of Southeast California. But it is important to many other states as well. It may not provide a disproportionate part of their annual precipitation but a good monsoon versus a poor monsoon has an impact on many states. As you can see, it is even more important to Mexico. |
| There are more than four types but these are the main ones. We will go into detail on each of them in the body of this article. But it is really simple when you think about a high being clockwise and a low being counterclockwise. Where you have a low west of a high, the air will be shuttled to the north from Mexico. So first look for the position of the main high-pressure area. Then look for where the low is. You will be able to figure out which way the wind will be blowing. If it is coming from where moisture is, it is likely to rain. |
Updated at 3:05 p.m. EST February 17, 2023 to incorporate information on the latest Sudden Stratospheric Warming (SSW) event
On the third Thursday of the month right on schedule NOAA issued what I describe as their Four-Season Outlook. The information released also included the MId-Month Outlook for the single month of March plus the weather and drought outlook for the next three months. I present the information issued and try to add context to it. It is quite a challenge for NOAA to address the subsequent month, the subsequent three-month period as well as successive three-month periods for a year or a bit more.
It is very useful to read the excellent discussion that NOAA issues with this Seasonal Outlook. The CPC/IRI analysis suggests that ENSO will very soon return to Neutral with a La Nino bias and gradually transition to true Neutral, Neutral with an El Nino bias, and then solidly El Nino. Confidence in the first part of that sequence of transitions is higher than in the latter part of the sequence.
NOAA updates many of its weather outlooks daily or even more frequently and in many cases issues a discussion with those outlooks. We provide a daily report which focuses on the shorter-term predictions but has links to all the partial-month outlooks. One of the reports issued by NOAA only gets updated on Fridays and since this covers weeks 3 and 4 it is very important. The discussion that gets issued with this week 3-4 NOAA report is often where possible changes to the weather pattern are first identified.
So we have decided to issue a special report on Fridays in which for a subset of the information we show the actual forecast maps not just provide the links. This makes it easier for the reader. We will also include at the end of the article the other information from the daily article
When the Week 3-4 Outlook is issued on Friday, we have a 28-day view of the future. It is important to recognize that the forecasts do not always work out as predicted. But in the article, there are links to obtain updated forecasts. This is important because it appears that changes are happening and the current view of the next 28 days differs substantially from the Monthly Outlook issued just a few days ago.
At the end of every month, NOAA updates their Outlook for the following month which in this case is September. They also issue a Drought Outlook for the following month. We are reporting on that tonight.
There have been some significant changes in the Outlook for September and these are addressed in the NOAA Discussion so it is well worth reading. We highlighted some of the important changes within the NOAA Discussion.
Of significant interest is the Drought Outlook for September. It is again a big improvement but unfortunately, it probably is a one-month event. We have also included four months of Wildland Fire Potential Outlooks and also a map showing the year-to-date precipitation in the West. We also included a Monsoon Update.
Today is the third Thursday of the month so right on schedule NOAA has issued what I describe as their Four-Season Outlook. The information released also includes the Early Outlook for the single month of September plus the weather and drought outlook for the next three months. I present the information issued and try to add context to it. It is quite a challenge for NOAA to address the subsequent month, the subsequent three-month period as well as successive three-month periods for a year or a bit more.
“The La Niña signature is likely to fade during FMA and MAM 2023, given that La Niña and ENSO-neutral are about even odds”
You can take La Nina out of the forecast, but the warming trend continues. But the Outlook is for a wetter CONUS starting in AMJ 2023. For many parts of CONUS, 2023 will be wetter than 2022. At least that is what NOAA is predicting right now.
NOAA updates many of their weather outlooks and in many cases issues a discussion with those outlooks. On Fridays, they issue a week 3 – 4 outlook which is farther out than the typical 10-day forecast and the discussion is excellent. So we have decided to issue a weekly special report on Fridays.
When the Week 3-4 Outlook is issued, we have a 28-day view of the future. It is important to recognize that the forecasts do not always work out as predicted. But in the article, there are links to obtain updated forecasts. Since we are publishing this article on Sunday we only have a 26-day view of the future. Sorry about that.
We have also taken a look at the state temperature and precipitation rankings for July and Year to Date (YTD). It is not a surprise that they differ. We provided that information in a recent article but thought it useful to repeat it here for those who did not happen to read the other article. There is value in relating the future outlook to the prior month and to the YTD.
NOAA updates many of their weather outlooks and in many cases issues a discussion with those outlooks. On Fridays, they issue a week 3 – 4 outlook which is farther out than the typical 10-day forecast and the discussion is excellent. So we have decided to issue a weekly special report on Fridays.
When the Week 3-4 Outlook is issued, we have a 28-day view of the future. It is important to recognize that the predictions do not always work out as predicted but in the article, there are links to obtain updated predictions.
It is somewhat surprising that there is as much difference between the first 14 days and the second 14 days of the 28-Day Forecast Period. The North American Monsoon is strong throughout the 28-Day Forecast Period. It is stronger at the beginning and slowly returns towards what is a normal Monsoon. Heat will be a hazard.
Today is the third Thursday of the month so right on schedule NOAA has issued what I describe as their Four-Season Outlook. The information released also includes the Early Outlook for the single month of August plus the weather and drought outlook for the next three months. I present the information issued and try to add context to it. It is quite a challenge for NOAA to address the subsequent month, the subsequent three-month period as well as successive three-month periods for a year or a bit more.
The three-month period Jan/Feb/Mar next year seems to be when the overall precipitation situation improves but for some reason the temperature situation does not and may be worse for several months along parts of the Southern Tier. You can take La Nina out of the forecast, but the warming trend continues. For many parts of CONUS, 2023 will be better than 2022. At least that is what NOAA is predicting right now.
Here is what we are paying attention to this evening and the next two days from this afternoon’s NWS Forecast.:
...Excessive Rainfall and Severe Thunderstorms possible across northern tier... ...West cools down as Great Plains into Midwest warm up... ...Critical fire weather conditions to persist across the Great Basin this weekend...
