2024 Hurricane Season Official Forecast – Posted May 25, 2024

By Sig Silber May 25, 2024ClimateNo Comments

In this article, I present NOAA articles about the Atlantic Hurricane Season. One is the Outlook for this season and the other is a review of the 2023 Hurricane Season with an informative YouTube. I interweave these two a bit and hope that I do not confuse the reader. Then I provide some additional information on Atlantic Hurricanes and how they are influenced by the Atlantic Multidecadal Oscillation (AMO), the Bermuda High, and the phase of ENSO.

Some may have to click on “Read More” to access the remainder of this article.

NOAA Updates its ENSO Alert on February 8, 2024 – The El Nino Advisory Continues. The La Nina Watch Begins – Timing of the Transition is Uncertain

By Sig Silber February 9, 2024weatherNo Comments

On the second Thursday of every month, NOAA (really their Climate Prediction Center CPC) issues its analysis of the status of ENSO. This includes determining the Alert System Status. NOAA again describes their conclusion as “ENSO Alert System Status: El Nino Advisory La Nino Watch”

The timing of the transition is not very clear which will impact the reliability of the Seasonal Outlook to be issued next Thursday.

We have included an interesting animation from and a link to an ENSO Blog article by Tom Liberto

CLIMATE PREDICTION CENTER ENSO DISCUSSION

The second paragraph is what is important:

“The most recent IRI plume indicates a transition to ENSO-neutral during spring 2024, with La Niña potentially developing during summer 2024. Even though forecasts made through the spring season tend to be less reliable, there is a historical tendency for La Niña to follow strong El Niño events. The forecast team is in agreement with the latest model guidance, with some uncertainty around the timing of transitions to ENSO-neutral and, following that, La Niña. Even as the current El Niño weakens, impacts on the United States could persist through April 2024 (see CPC seasonal outlooks for probabilities of temperature and precipitation). In summary, a transition from El Niño to ENSO-neutral is likely by April-June 2024 (79% chance), with increasing odds of La Niña developing in June-August 2024 (55% chance).”

Below is the middle paragraph from the discussion last month.

“The most recent IRI plume indicates El Niño will gradually weaken and then transition to ENSO-neutral during spring 2024 . Some state-of the-art dynamical climate models suggest a transition to ENSO-neutral as soon as March-May 2024. The forecast team, however, delays this timing and strongly favors a transition to ENSO-neutral in April-June 2024. There are also increasing odds of La Niña in the seasons following a shift to ENSO-neutral. It is typical for El Niño to peak in December/early January, but despite weakening, its impacts on the United States could last through April (see CPC seasonal outlooks for probabilities of temperature and precipitation). In summary, El Niño is expected to continue for the next several seasons, with ENSO-neutral favored during April-June 2024 (73% chance).”

We now provide additional details. The level of uncertainty with respect to how this El Nino will play out has increased a bit.

CPC Probability Distribution

Here are the new forecast probabilities. The probabilities are for three-month periods e.g. JFM stands for January/February/March.

Here is the current release of the probabilities:

This chart shows the forecasted progression of the evolution of ENSO from the current El Nino State to Neutral and by the summer to La Nina. This kind of bar chart is not very good at showing uncertainty.

Here is the forecast from last month.

The analysis this month and last month are different. This month the probability of El Nino in MAM is much more than was expected last month. That is important.

NOAA Updates Its Seasonal Outlook on November 16, 2023 – El Nino Weather through Late Spring

By Sig Silber November 17, 2023weatherNo Comments

On the third Thursday of the month right on schedule NOAA issued their updated Seasonal Outlook which I describe as their Four-Season Outlook because it extends a bit more than one year into the future. The information released also included the Mid-Month Outlook for the following month plus the weather and drought outlook for the next three months. I present the information issued by NOAA 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 the twelve successive three-month periods for a year or a bit more.

First, Let’s Take a Look at the (mid-month) Outlook for December. It will be updated on the last day of November.

Then I present a graphic that shows both the preliminary Outlook for December and the three-month outlook for DJF 2023-2024. So you get the full picture in one graphic. For some, that may be all they are interested in. Others will be interested in the longer-term predictions and also the rationale supporting the predictions which is mostly provided by the NOAA discussion.

The top row is what is now called the Mid-Month Outlook for next month which will be updated at the end of this month. There is a temperature map and a precipitation map. The second row is a three-month outlook that includes next month. I think the outlook maps are self-explanatory. What is important to remember is that they show deviations from the current definition of normal which is the period 1991 through 2020. So this is not a forecast of the absolute value of temperature or precipitation but the change from what is defined as normal or to use the technical term “climatology”.

Notice that the outlook for next month and the three-month outlooks are somewhat different with respect to temperature and also to some extent precipitation. This tells us that January and February will be different than December to some extent.

The full NOAA Seasonal Outlook extends through December/January/February of 2025. All of these maps are in the body of the article. Large maps are there for December and the three-month period Dec/Jan/Feb. Small maps are provided beyond that through February of 2025 with a link to get larger versions of these maps.

NOAA provides an excellent discussion to support the maps.[Author’s Note: many other meteorological agencies see this El Nino being stronger than NOAA does so there is more than usual uncertainty relating to the more distant months.]

NOAA Updates their Seasonal Outlook – June 17, 2023

By Sig Silber June 17, 2023weatherNo Comments

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 July plus the weather and drought outlook for the next three months. I present the information issued by NOAA 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. A seasonal drought outlook is also issued.

It is very useful to read the excellent discussion that NOAA issues with this Seasonal Outlook. The overall level of confidence in the Seasonal Outlook is addressed in the NOAA discussion. It is best to read the full discussion but here are some of the highlights:

Re ENSO:

“NOAA’s CPC forecast calls for more than a 90 percent chance of El Niño persisting through JFM 2024 with a 56 percent chance of a strong El Niño (> 1.5 degrees C) during NDJ 2023.”

For July:

“Above normal temperatures are favored from the Four Corners region, across the central and southern Great Plains, the Southeast, and the Northeast.”
“A weakened monsoon during July across eastern Arizona and New Mexico is predicted”
“a strong subtropical ridge, which would favor above-normal precipitation from the southern Great Plains northward and into the Mid-Atlantic”
“a storm track across the northern Great Plains and into the Ohio River valley”

For JAS 2023:

“The highest probabilities (more than 50 percent) of above-normal temperatures are forecast across parts of California, the Pacific Northwest, Great Basin, Southwest, Gulf Coast, and East.”
“elevated probabilities of below-normal precipitation for parts of the Southwest, Pacific Northwest, and Great Lakes, while above-normal precipitation is favored across much of the Great Plains, parts of the Middle to Lower Mississippi Valley, Northern Rockies, and Florida Peninsula.”

Beyond JAS 2023:

“Above-normal temperatures remain the most likely outcome throughout much of the U.S. from ASO to OND 2023.”
“Beginning in NDJ 2023-24 through JFM 2024, predicted El Niño conditions result in enhanced chances for above-normal temperatures across the northern tier of the CONUS”
“During the winter 2023-24, above-normal temperatures are favored across the East”
“Precipitation outlooks during the fall 2023 through the winter 2023-24 relied upon El Niño composites and the consolidation tool with an increased chance of above (below)-normal precipitation across the southern (northern) tier of the CONUS.”
“The largest probabilities (50 percent for above) are forecast across parts of the Southeast from NDJ 2023-24 through JFM 2024 based on a strong, reliable wet signal associated with El Niño.
“During the spring and summer 2023, the precipitation outlooks are based mostly on decadal trends.”

November 3, 2022: U.S. 48-Hour Weather Report and Intermediate-Term Outlooks; Tropical and World Precipitation

By Sig Silber November 4, 2022weatherNo Comments

Here is what we are paying attention to this evening and the next 48 hours from this evening’s NWS Forecast.

...Moderate to heavy mountain snow moving across the central Rockies today
into early Friday...

...Severe thunderstorms likely across the southern Plains on Friday ahead
of and along a potent cold front...

...Above-average temperatures across northern Plains and Midwest today;
spreading eastward this weekend...

...Atmospheric River will bring widespread rain and high-elevation snow
across the Pacific Northwest...

NOAA Updates its Four Season Outlook on October 20, 2022 – Yet Another La Nina Winter

By Sig Silber October 21, 2022weatherNo Comments

Preparing to say goodbye to La Nina early in 2023. Now it looks like La Nina will remain until Spring.

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 November 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. NOAA seems to be more confident about making predictions beyond six months. They even predict a good monsoon next summer which they never do this far in advance.

I will be writing a subsequent article on the challenges to the Agriculture Sector in certain parts of CONUS.

NOAA Updates its Four Season Outlook on September 15, 2022 – One More La Nina Winter

By Sig Silber September 17, 2022weatherNo Comments

Preparing to Say Goodbye to La Nina Early in 2023. It seems as if it is taking forever but if the forecasters are correct, we are talking about four to six months from now.

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 October 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. NOAA seems to be more confident about making predictions beyond six months. They even predicted a good monsoon next summer which they never do this far in advance.

September 9, 2022 Looking Ahead 28 Days Plus our usual 48-hour report.

By Sig Silber September 10, 2022weatherNo Comments

After the first week, there is a change in the pattern with more moisture in the Northern Tier and more heat first in the Great Plains and then drifting to the East. The anomalies in the second half of the 28-day period moderate.

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 (which most will read on Saturday) 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.

The regular 48-hour forecast article is included in this article and follows the 28-Day Analysis.

This week we also show the state rankings for August and compare them to the state rankings year to date (YTD).

NOAA Updates July Outlook – June 30, 2022 – Not Much Change – Some Ocean Indicators are Surprising

By Sig Silber July 1, 2022weatherNo Comments

Updated at 2:30 am EDT July 2, 2022 to incorporate the Week 3 – 4 Outlook which suggests that the second half of July will not be as cool in the Northwest but perhaps less warm elsewhere and the Monsoon may be less robust but some other areas will be less dry.

At the end of every month, NOAA updates their Mid-Month Outlook for the following month which in this case is July. They also issue a Drought Outlook for the following month and update the three-month Drought Outlook. We are reporting on that tonight. The updated Outlook is very similar to the Mid-Month Outlook. This is surprising since the Mid-Month Outlook was issued two weeks ago and there usually are more changes in that period of time.

For temperature, the shape and location of the large dry anomaly have changed a bit. The cool anomaly in the Northwest is now slightly larger. For precipitation, the area where an above-average Monsoon is forecasted is a little larger and shifted a bit to include more of New Mexico. there is a new small dry anomaly

We provide partial-month Outlooks for the first 22 days of July which allows us to somewhat assess if the Monthly Outlook is consistent with the partial-month Outlooks and it generally is. But we will not be able to answer that question definitively until the Week 3-4 Outlook is issued tomorrow. We will provide an update at that time.

We also provide enough information for readers to understand any changes from the Mid-Month Outlook and we try to figure out why these changes were made. Many of the changes are explained in the NOAA discussion which is included in the article. The partial-month forecasts that we have provided show how NOAA thinks this will play out as the weather pattern evolves during July.

There is also a discussion of the ENSO condition which is ever so slightly different than what NOAA used to develop the Mid-Month Outlook. But there is a fairly strong signal that this La Nina will end in late winter 2022/2023. The impacts on weather may not be noticed until Spring. But that is just the current forecast and can change.

We have also begun our tropical storm coverage. Yes, it is that time of the year. We are also providing special coverage of the Monsoon by providing the links to those daily updates.

NOAA Issues their Four-Season Outlook on June 16, 2022 – One or Two Month Delay in Southern Tier Shedding La Nina Weather

By Sig Silber June 17, 2022weatherNo Comments

.Updated at 5 pm EDT on June 18 to incorporate the Week 3 – 5 Outlook issued on June 17 which is somewhat different than the full-month outlook so it is of some interest.

Change Appears to be Coming – but a bit slower than it looked last month.

Even though the IRI analysis issued last week seems to show the La Nina will end perhaps a bit sooner than previously forecast, the weather outlooks seem to show weather impacts lasting a month or two longer. Uncertainty in the ENSO forecast introduces greater than usual uncertainty in the Seasonal Outlook. But the decadal trends are strong so we see a lot of that in the longer-term outlooks.