NOAA Updates The Outlook For June 2020 – Very Significant Changes!

Written by Sig Silber

At the end of every month, NOAA issues an update to their Early Outlook for the following month, in this case, June 2020, which was issued as usual on the Third Thursday of the month. Today, ten days later, NOAA has issued their Updated Outlook for June. The changes are very significant. With respect to temperature, the area that was supposed to be EC has changed significantly from the North Central to the extreme Northwest. With respect to precipitation, there is hardly any resemblance to the prior forecast as it applies to the Northwest, the Southeast, the Central Great Plains, and the Mid-Atlantic/New England. The net result is somewhat more drought and a different location for drought involving, in particular, Western Oklahoma, Northwest Texas, and the Rio Grande Valley in New Mexico including all of Eastern New Mexico.

Some housekeeping: On May 24, 2020, we published Part I of our analysis of the NOAA and JAMSTEC Three- to Four- Season Outlook and that can be accessed here. In that report, the June 2020 Early Outlook was issued. This article presents the NOAA update of their Early temperature and precipitation Outlook for June and the most recent Drought Forecast update for the month of June.

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Now let us address the NOAA Update of the June 2020 Forecast.

First, we will compare the NOAA Early Outlook for June 2020 with the newly issued update.

Early Outlook Temperature

Updated Temperature Outlook

Early Outlook Precipitation

Updated Precipitation

Here is the discussion released today:

Prognostic Discussion for Monthly Outlook NWS Climate Prediction Center College Park MD 300 PM EDT Sun May 31 2020

30-DAY OUTLOOK DISCUSSION FOR JUNE 2020

The updated monthly temperature and precipitation outlooks for June 2020 are based on the latest dynamical model guidance, including the NCEP CFS and GEFS and ECMWF ensemble prediction systems, WPC temperature and precipitation forecasts for the first week of the month, the CPC 6-10 day, 8-14 day, and week 3-4 temperature and precipitation outlooks, and current climate conditions. The enhanced phase of the Madden-Julian Oscillation (MJO) propagated eastward across the Western Pacific during late May and is now in the Western Hemisphere. Enhanced convective activity over the Caribbean and southern Gulf of Mexico may enhance precipitation for parts of the southeastern CONUS in the second week of June. ENSO neutral conditions are present at this time and likely to continue into summer.

Dynamical model circulation forecasts for the first week of June predict a mid-level trough over the North Pacific extending along the Pacific coast of North America with an amplified ridge downstream over the central and eastern CONUS. Models including the ECMWF and GEFS ensemble prediction systems indicate a de-amplification of the circulation pattern in the second week of the month, while maintaining troughing from the Gulf of Alaska to the Pacific Northwest and ridging and above normal heights over the Southwest into the southern central CONUS. Uncertainty between model forecasts increases in the second half of the month, while dynamical models generally persist positive 500-hPa height anomalies for much of the western CONUS and, in the cas e of the ECMWF ensemble mean forecast, across the entire CONUS. Weak negative 500-hPa height anomalies persist over parts of the North Pacific in dynamical model forecasts, including the ECMWF, NCEP CFS and the Subseasonal Experiment (SubX) multi-model ensemble (MME), for late June.

The updated June temperature outlook indicates increased probabilities of above normal average temperatures for the month over most of the CONUS under a persistent ridge through at least the first half of the month. Probabilities exceed 60 percent for parts of the Central Plains, where the probabilities of above normal temperatures during weeks 1 and 2 are greatest and predicted to persist in the CPC week 3-4 outlook. Equal chances (EC) of below, near and above normal temperatures are indicated for parts of the Pacific Northwest, where below normal temperatures are likely during much of the first half of the month, under a predicted trough, and a warming is likely later in the month, as 500-hPa heights are predicted to rise. Above normal temperatures are likely for all of the state of Alaska for the June average, under primarily positive 500-hPa height anomalies throughout the month.

The updated June precipitation outlook indicates increased chances of below normal rainfall over parts of the central and eastern CONUS, including parts of the Southern and Central Plains from northern Texas northward across Oklahoma into Kansas and much of Nebraska and northeastward across the Central Mississippi Valley as far as Illinois, under a predicted ridge particularly during the first two weeks of June. An additional area of enhanced probabilities of below normal precipitation is indicated over the Mid-Atlantic region into southern New England, supported by a consolidation of weeks 1 through 4 precipitation forecasts from the NCEP GEFS and CFS. Above normal precipitation continues to be likely for the Gulf Coast region, as in the half-month lead precipitation outlook, due to predicted enhanced convective activity over the Gulf of Mexico by dynamical models primarily during week 2. Dynamical model forecasts, including the ECMWF and GEFS, of likely above normal precipitation extending from the Southeast northward into the Central Mississippi, Tennessee and Ohio Valleys during week 2 decreases the probability of below normal June average precipitation for these regions, despite the prediction of large scale ridging and below normal precipitation for the first week of the month. A predicted trough along the Pacific Coast early in June increases the likelihood of above normal precipitation for the Pacific Northwest in the June outlook. Dynamical model forecasts indicate likely above normal precipitation for parts of Arizona and New Mexico into the Four Corners region during the first week of the month, however precipitation amounts are likely to be small, and dynamical model forecasts predict a drying of this region from the week 2 period forward. Therefore, equal chances (EC) is indicated in the June precipitation outlook for the Southwest region. Above normal precipitation continues to be likely for much of southern Alaska from the Aleutians across the south coast of the Alaska Mainland to the Alaska Panhandle, as indicated by dynamical model forecasts of predicted weak positive or negative 500-hPa height anomalies and potential storm tracks.

Visual Consistency Testing.

It is useful to see how the full-month forecast fits with the set of partial-month forecasts that we have. These will continue to update in this article. It is important to remember that with the partial-month forecasts, we generally have about 25 days of the subsequent month to look at when we do this at the end of the month as we are doing now. It depends on what day of the week the month ends. So this month, which ended on a Sunday, we are missing a forecast that includes the last four days of the month. So we are in great shape for the visual consistency testing this month.

First Temperature

The new monthly forecast is to the right. Does it appear to be reflective of the four parts of the month for which we have forecasts? →			↑ ← The Week 3 – 4 forecast was updated Friday May 29 so we may want to update the commentary when the Week 3 – 4 update is reissued on June 3, 2020. But that probably will not be necessary. At this point, we have forecasts for 26 days of the 30 days in June and the fit looks pretty good. But where is the cool anomaly shown in the short-term forecasts?

And Precipitation

The new monthly forecast is to the right. Does it appear to be reflective of the four parts of the month for which we have forecasts? →			↑ ←The Week 3 – 4 forecast was updated Friday May 29 so we may want to update the commentary when the Week 3 – 4 update is reissued on June 3, 2020. But that probably will not be necessary. At this point, we have forecasts for 26 days of the 30 days in June and the fit looks pretty good

Because the end of the month forecast was issued on a Sunday, we see no point in publishing the prior Week 3 – 4 Discussion as the monthly discussion is a lot more current.

Sometimes it is useful to compare the three-month outlook to the forecast for the first of the three months. It shows how much the pattern changes over the three-month period.

One can mentally subtract the First-Month Outlook from the Three-month Outlook and create the Outlook for the last two months in the three-month period.

And with respect to drought, this was also issued on May 31, 2020.

Latest Monthly Assessment – Drought intensification and development occurred during May across the central to southern Great Plains due to insufficient rainfall coupled with periods of above normal temperatures. According to the U.S. Drought Monitor valid on May 26, drought coverage across Kansas increased from 6.85 to 27.46 percent since late April with Oklahoma experiencing an increase from 3.94 to 14.44 percent. Additional development is likely across the central to southern Great Plains during early to mid-June with the combination of above normal temperatures and below normal precipitation. Development is also favored across parts of New Mexico and Wyoming. Much of the eastern U.S. remains drought-free, but development is forecast across parts of New England where short-term precipitation deficits are increasing and the updated June outlook calls for elevated probabilities of above normal temperatures and below normal precipitation.

Heavier rainfall during mid to late May resulted in improving drought conditions across southern Texas along with much of the Gulf Coast and Florida. Continued improvement or removal of drought is forecast for these areas, based on the likelihood of above normal precipitation through at least the first half of June. Meanwhile, drought persistence is most likely across ongoing drought areas of the West and North Dakota. Persistence is also favored for drought across Puerto Rico and Hawaii, while Alaska is likely to remain drought-free through the end of June.

Looking back on May to relate the forecast for June to the actuals in May

First May Temperature (30 out of 31 days).

And then May Precipitation (30 out of 31 days).

We then show the new forecast and the prior month actuals (less one day) side by side.

Conclusion

The purpose of this article was to present the updated Outlook for June 2020 and compare it with the Early Outlook. It is not to critique the updated Outlook for June based on our opinions but we point out possible inconsistencies if we find them. We have assessed the extent to which the monthly outlook seems to fit with the other forecasts provided by NOAA. In reality, all forecasts are obsolete when issued as the situation changes day by day or six hours by six hours i.e. each new model run. In our other articles, we continually examine the current forecasts from NOAA including the Day 1- 5, 6-10, 8-14 and Week 3 and 4. So we are continually looking at approximately 25 days into the future.

On June 11, 2020, IRI/CBC will issue their ENSO forecast and we will present that and critique it. It is an ongoing process and we attempt to provide our readers with the best current assessment of the next approximately 25 days (except when we cover the Four-Season Analysis or medium-frequency cycles such as ENSO), so our analysis is pretty much ongoing. We also publish a “LIVE” Weather Article which updates in real-time to reflect NOAA Weather Headlines and for those interested provides detailed information down to current warnings in place. All of our reports including past versions of these reports can be located via the Directory/Archive which can be accessed here.