August 6, 2019 – Intermediate-Term Weather Report – Pattern Changing

Written by Sig Silber

It may take a week or so but the Monsoon almost appears to be in its end stage but a minimum is is forecast to enter a Break Period but not for a week or so. The weather pattern is shifting to the north. Tonight we provide additional information on how to understand the North Amerian Monsoon which directly or indirectly impacts a very large part of CONUS. And as usual we provided the approximately 25-day Intermediate Term Forecast.

Please share this article – Go to the very top of the page, right-hand side for social media buttons. Also, feel free to send this article to anyone you feel will benefit from it. For those who are interested in the short-term situation, we refer you to our Severe Weather Report which is republished nightly and you can find the latest version by consulting the Directory by clicking here and then clicking on the latest version of the Severe Weather Report which will be near the top of the Directory.

August Forecast Update.

If you missed our Update Article which you can access here, this is a summary.

Status of the Monsoon

We are moving into August so we are passed the point where the statistics set the odds in favor of a late and slow start to the Monsoon. We are now in the heart of the Monsoon Season and the performance of the Monsoon in August may not be much impacted by the slow start.

Let’s go back to our discussion of the typical configurations of the Monsoon especially with regards to severe weather.

I only have this information based on the perspective of Arizona but you can extrapolate the interpretation to beyond Arizona. I show the four maps and the discussion of each map can be found here.

I prepared a little table to provide some information on when the different types might occur during the Monsoon. The full information is in the referenced document.

Notice that during the Monsoon the location of the Four Corners High Migrates not always in a predictable way but there is a pattern to it and you can see that in the graphics above.

So which type of positioning is this?

Let’s look at the MId-Atmosphere pattern.

It looks somewhat like Type IV from the four choices provided. But the High is farther east and north. Is it Type I? I hope not.

Performance of the Monsoon this Year.

I have the data for Arizona. I do not have it for New Mexico as a whole but could put it together –  I assume the Albuquerque NWS will issue something on that soon. In a way I have other graphics that show it for the Intermountain West and use those often in my Thursday Report. But tonight I am presenting the data for Arizona as Arizona is the key Monsoon State. 

Arizona Monsoon Tracker

Back to Monsoon Patterns.

I do have an analysis for New Mexico. But it is different than the one issued by Arizona and it is not focused on severe weather necessarily but useful none the less. You can find it here but I am presenting it in full tonight.

It is a little harder to follow since they do not locate the Four Corners High location as specifically as in the Arizona analysis and it and does not correspond easily to the Arizona analyis. But here it is and I will try to relate it to the Arizona analysis. 

Pattern A: This is like the Arizona Type III and IV patterns.
Upper level high pressure centered over the southern Great Plains allows deep-layer south to southeast flow to develop over the desert southwest on the western periphery of the high. This pattern opens the door to moisture pooling over the Gulf of Mexico, northern Mexico, and the Gulf of California. Monsoon “bursts” are common in this pattern, resulting in significant amounts of precipitation for Arizona and New Mexico. Remnant tropical systems from the eastern Pacific can be especially productive for rainfall over the region in this pattern. If the high pressure system is persistent and does not migrate, the summer can be especially wet over central and western New Mexico. The example below shows the mean 500mb geopotential height field (left) and the total precipitation for August 2006 (right). The 2006 monsoon season was the wettest on record for Albuquerque and for the state of New Mexico.
	August 2006 total precipitation from PRISM Climate Group Oregon State University.

And then

Pattern B:   This is the Canonical Four Corners High.
Upper level high pressure centered over the Four Corners region or southern Colorado allows easterly waves to shift westward across the southern United States into the desert southwest. Easterly waves can also bring significant increases in moisture, particularly if associated with a remnant tropical system or large convective clusters from the Great Plains. These features typically are preceded by subsidence and a down-tick in storm coverage followed by ascent and significant up-ticks in storm coverage. The example below shows the mean 500mb geopotential height field (left) and the total precipitation for July 2008 (right). Remnant moisture from Hurricane Dolly shifted northwest up the Rio Grande Valley during late July 2008 and resulted in significant flash flooding around Ruidoso.  [Editor’s Note: I was there during that event and managed to get our party out of there before the road was closed. The river near the highway was flowing over the highway so it was quite interesting].
	July 2008 total precipitation from PRISM Climate Group Oregon State University.

And then

Pattern C:  This is like the Arizona Type II Pattern.
Upper level high pressure centered west of NM allows low level moisture from the Great Plains to shift southwest into the area as a result of back door frontal boundaries. This can be particularly true when large convective complexes move off the front range of the Rockies. This pattern tends to be quite favorable for the Rio Grande Valley as storms migrate off the Jemez Mountains down the valley. In this pattern, Albuquerque receives precipitation in the 00-12Z period 2.5 times more often than in the 12-00Z period. North to northwest steering flow in this pattern is also highly favorable for the high plains of eastern New Mexico as convection moves off the central mountain chain. Severe thunderstorms are more likely in this pattern for the eastern plains if enough shear is available in the atmosphere. The example below shows the mean 500mb geopotential height field (left) and the total precipitation for September 2009 (right).
	September 2009 total precipitation from PRISM Climate Group Oregon State University.

And then

Pattern D:  This is like Pattern B but the Four Corners High is so large it is choking off the Monsoon.
A sprawling area of upper level high pressure centered directly over New Mexico and Arizona suppresses moisture intrusions into New Mexico, leads to warming mid level temperatures, stronger subsidence, and forces the development of showers and storms to rely heavily on the recycling of low level moisture already in place. Very light steering flow in this pattern leads to slow storm motions and increases the risk for flash flooding from highly localized heavy rainfall. The example below shows the mean 500mb geopotential height field (left) and the total precipitation for July 2007 (right). Note the precipitation maximums across New Mexico are Arizona are more spotty and confined to areas in and around the higher terrain.
	July 2007 total precipitation from PRISM Climate Group Oregon State University.

I have tried to organize the images in a similar way to the Arizona analysis given that the two sets of graphics were intended for different purpose namely precipitation versus severe weather.  But sometimes looking at things from slightly different perspectives is useful. There is not a tremendous amount of difference between the two sets of graphics.

So here is whatI came up with.

	↑ Above to the Left is a set up similar to Type I in the Arizona Graphics (but without the twin Highs that make it a candidate for severe weather) and the Upper Right is similar to Type II in the Arizona Graphics ← Off to the left there is a set up somewhat similar to the graphic above it. But here the Four Corners High is so large it chokes off the inflow from Mexico.
Off to the right is a set-up somewhat similar to Type IV in the set of Arizona Graphics but Albuquerque is discussing it in terms of a more persistant pattern than transient as discussed in the Arizona information.  →

I do  not know if the above is useful or not to readers. I prepared it to help me understand the differences.

Shifting Gears Let’s Take a Look at Tropical Activity

First looking at the Atlantic and the Gulf of Mexico

Switching to the Eastern Pacific

And the Central Pacific.

Central Pacific Storms

Flossie is now forecast to miss Hawaii and with much reduced wind speeds it would have been more beneficial than harmful. We will see.  Flash flooding is always a risk with a tropical event. But hopefully they will get some precipitation from  Flossie and decent surf conditions for a day or so.

Updates on individual named storms can be obtained here.

Recent CONUS Weather

Here is the recent history of the overall atmospheric pattern for North America and the North Pacific.

And now looking at the recent weather.

The 30 Days ending a week ago Saturday	The 30 Days ending last Saturday
Dry area less intense but more widespread. Temperature anomaies a bit less amplified but more so in the Southwest due to poor Monsoon.	Certainly wetter but not yet in Arizona and New Mexico. Certainly cooler in the West and less warm in the NE Quadrant.

The 30 day change was substantial.

Summary of the Forecast

We now provide our usual summary first for temperature and then for precipitation of small images of the four short-term maps. You can click on these maps to see larger versions. The easiest way to return to this report is by using the “Back Arrow” usually found at the top left corner of your screen to the left of the URL Box. Larger maps are available later in the article with the discussion and analysis.

Sometimes it is useful to see the evolution of the forecasts from the 1 – 5 Day, 6 – 10 Day (which NOAA considers to be Week-1 of their intermediate forecast) , 8 – 14 Day (which NOAA considers to be Week-2) and Week 3 and 4 (which after being issued overlap with Week-2). I do not have comparable maps for the Day 1 – 5 forecast in the same format as the three maps we generally work with. What I am showing for temperature is the Day 3 Maximum Temperature and for precipitation the five-day precipitation: the latter being fairly similar in format to the subsequent set of the maps I present each week but showing absolute QPF (inches of precipitation) not QPF deviation from Normal.

First Temperature

And then Precipitation

A. Now we will begin with our regular approach and focus on Alaska and CONUS (all U.S.. except Hawaii).

Water Vapor.

This view of the past 24 hours provides a lot of insight as to what is happening.

You can see from this animation that there is a Western Anticylonic Circulation. It is the Monsoon. The Monsoon High is often referred to as the Four Corners High, it’s favorite location.

Tonight, Monday, August 5, 2019, as I am looking at the above graphic, you see some rain events moving into Arizona and New Mexico from Mexico.

We now discuss Atmospheric Rivers i.e. thick concentrated movements of water moisture. More explanation on Atmospheric Rivers can be found by clicking here or if you want more theoretical information by clicking here. The idea is that we have now concluded that moisture often moves via narrow but deep channels in the atmosphere (especially when the source of the moisture is over water) rather than being very spread out. This raises the potential for extreme precipitation events. You can convert this graphic into a flexible forecasting tool by clicking here. One can obtain views of different geographical areas by clicking here.

This graphic does not cover all of CONUS but it does provide a very good view of what is happening in the Pacific and the North American West Coast.

And this graphic provides a better view of all of CONUS.

This graphic shows the Atlantic.

And Now the Day One and Two CONUS Forecasts (These graphics have recently been revised by NOAA and I think greatly improved).

Day One CONUS Forecast	Day Two CONUS Forecast
These graphics update and can be clicked on to enlarge but my brief comments are only applicable to what I see on Monday night prior to publishing.
You can easily see the convective activity.

Additional useful forecasts are available from our Severe Weather Report which this week can always be located via this directory.

60 Hour Forecast Animation

Here is a national animation of weather fronts and precipitation forecasts with four 6-hour projections of the conditions that will apply covering the next 24 hours and a second day of two 12-hour projections the second of which is the forecast for 48 hours out and to the extent it applies for 12 hours, this animation is intended to provide coverage out to 60 hours. Beyond 60 hours, additional maps are available at links provided below. The explanation for the coding used in these maps, i.e. the full legend, can be found here although it includes some symbols that are no longer shown in the graphic because they are implemented by color coding.

The below makes it easier to focus on a particular day.  The best way to read them is from left to right on the first row and then from left to right in the row below it.

include(“/home4/aleta/public_html/pages/weather/modules/Weather_Map_by_Day_Matrix.htm”); ?>

What is Behind the Forecasts? Let us try to understand what NOAA is looking at when they issue these forecasts.

Below is a graphic which highlights the forecast surface Highs and the Lows re air pressure on Day 7. The Day 3 forecast can be found here. The Day 6 Forecast can be found here.

There really is not an Aleutian Low at this point although there is a Low near Kamchatka with surace central pressue of 1,000 hPa. There is an Arctic High with surface central  pressure of 1020 hpa and a Greenland High with surface central pressure of 1028 hPa. There is a Low over Newfoundland with surface central pressure of 1004 hPa. The Hawaiian High has surface central pressure of 1020 hPa. It is split with a Low with surface central pressure of 1016 hPa between the two lobes of high pressure.And again there is an inverted Trough in the Sea of Cortez extending into the Southwest like what we often see during the Monsoon. We even see what looks like the Four Corners High which is the signature of the North American Monsoon (NAM) with surface central pressure of 1020 hPa. The mid-level high seen on a different graphic is much farther east. The Bermuda High exends into the Southeast but much less than recently and far out to sea has surface central pressure of at least 1020 hPa. 

include(“/home4/aleta/public_html/pages/weather/modules/Air_Pressure_Map_by_Day_Matrix.htm”); ?>

Looking at the current activity of the Jet Stream. The below graphics and the above graphics are very related.

Not all weather is controlled by the Jet Stream (which is a high altitude phenomenon) but it does play a major role in steering storm systems especially in the winter The sub-Jet Stream level intensity winds shown by the vectors in this graphic are also very important in understanding the impacts north and south of the Jet Stream which is the higher-speed part of the wind circulation and is shown in gray on this map. In some cases however a Low-Pressure System becomes separated or “cut off” from the Jet Stream. In that case, it’s movements may be more difficult to predict until that disturbance is again recaptured by the Jet Stream. This usually is more significant for the lower half of CONUS with the cutoff lows being further south than the Jet Stream. Some basic information on how to interpret the impact of jet streams on weather can be found here and here. I have not provided the ability to click to get larger images as I believe the smaller images shown are easy to read.

Current	Day 5
You can see the current pattern here. The pattern is fairly far north.	The pattern is forecast to shift east and will be predominately zonal.

Putting the Jet Stream into Motion and Looking Forward a Few Days Also

To see how the pattern is projected to evolve, please click here. In addition to the shaded areas which show an interpretation of the Jet Stream, one can also see the wind vectors (arrows) at the 300 Mb level.

This longer animation shows how the jet stream is crossing the Pacific and when it reaches the U.S. West Coast is going every which way.

Click here to gain access to a very flexible computer graphic. You can adjust what is being displayed by clicking on “earth” adjusting the parameters and then clicking again on “earth” to remove the menu. Right now it is set up to show the 500 hPa wind patterns which is the main way of looking at synoptic weather patterns. This amazing graphic covers North and South America. It could be included in the Worldwide weather forecast section of this report but it is useful here re-understanding the wind circulation patterns.

500 MB Mid-Atmosphere View

The map below is the mid-atmosphere 7-Day chart rather than the surface highs and lows and weather features. In some cases, it provides a clearer less confusing picture as it shows only the major pressure gradients. This graphic auto-updates so when you look at it you will see NOAA’s latest thinking. The speed at which these troughs and ridges travel across the nation will determine the timing of weather impacts. This graphic auto-updates I think every six hours and it changes a lot. Thinking about clockwise movements around High-Pressure Systems and counterclockwise movements around Low-Pressure Systems provides a lot of information.

include (“/home4/aleta/public_html/pages/weather/modules/500_Millibar_by_Day_Matrix.htm”); ?>

Here is the seven-day cumulative precipitation forecast. More information on how to interpret this graphic is available here.

Four – Week Outlook: Looking Beyond Days 1 to 5, What is the Forecast for the Following Three + Weeks?

I use “EC” in my discussions although NOAA sometimes uses “EC” (Equal Chances) and sometimes uses “N” (Normal) to pretty much indicate the same thing although “N” may be more definitive.

First – Temperature

6 – 10 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on August 5, 2019 was 4 out of 5

8 – 14 Day Temperature Outlook issued today (Note the NOAA Level of Confidence in the Forecast Released on August 5, 2019 was 3 out of 5).

–

Looking further out.

Now – Precipitation

6 – 10 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on August 5, 2019 was 4 out of 5)

8 – 14 Day Precipitation Outlook Issued Today (Note the NOAA Level of Confidence in the Forecast Released on August 5, 2019 was 3 out of 5)

Looking further out.

Here is the 6 – 14 Day NOAA discussion released today August 5, 2019

6-10 DAY OUTLOOK FOR AUG 11 – 15 2019

Today’s GFS, ECMWF, and Canadian ensemble mean solutions are in good agreement over the forecast domain for the 6-10 day period. A ridge is forecast over western Alaska and a trough is predicted over the Alaska Panhandle and the Pacific Northwest. Downstream, model solutions continue to indicate a ridge over the central CONUS, and a trough over the eastern CONUS. The manual 500-hPa height blend is based primarily on the ensemble means from the GFS and ECMWF models. The resultant manual blend indicates strong positive 500-hPa height anomalies over much of western Alaska, while weak 500-hPa height anomalies are predicted over most of the CONUS except for the northeastern COUNS where strong negative 500-hPa height anomalies are indicated.  

Above normal temperatures are favored over the Pacific Northwest coast south to much of the southern CONUS. This is due, in part, to above normal SSTs near the Pacific. Above normal temperatures are also favored over the Southern Rockies, the Central-Southern Plains, and the Lower Mississippi Valley, due to the anomalous ridge aloft. Above normal temperatures are likely for the Gulf Coast, the Florida Peninsula, and the southeastern CONUS, consistent with the consolidation tool. Near to below normal 500-hPa heights over the Northern CONUS lead to enhanced probabilities of below normal temperatures over the northern and central Rockies, the Northern Plains, the Upper Mississippi Valley, the Great Lakes, the Ohio Valley, parts of the Middle Atlantic, and the Northeast. Above normal temperatures are most likely for southwestern mainland Alaska, the Aleutians and the Alaska Panhandle underneath above normal 500-hPa heights and also due to the influence of above normal sea surface temperatures. 

Model solutions predict weakly enhanced monsoon moisture leading to above normal precipitation from the southwestern New Mexico northeastward to much of the Great Plains. Above normal precipitation is likely from the Pacific Northwest eastward to the Great Plains, and parts of the the Upper and Middle Mississippi Valley, due to potential frontal activity in these regions. Enhanced above normal precipitation is also favored for the the eastern Gulf Coast region, the Ohio and Tennessee Valleys, consistent with the consolidation tool. Below normal precipitation is likely over the central and southern Rockies, much parts of Texas, related to the subtropic ridge over the southern CONUS. Below normal precipitation is favored across the southern coast of mainland Alaska, the Alaska Panhandle and the Aleutians, underneath forecast near to above normal 500-hPa heights. Above normal precipitation is favored for central and northern Alaska consistent with combined ECMWF ensemble guidance.

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Above average, 4 out of 5, due to good agreement between models on the predicted 500-hPa height pattern, offset by some disagreement due to timing of specific features.   

8-14 DAY OUTLOOK FOR AUG 13 – 19 2019 

During Week-2, the predicted 500-hPa circulation pattern is similar to the pattern for the 6-10 day period. The manual blend and each of the ECMWF, and NCEP GFS ensemble means continue to predict weak 500-hPa height anomalies over most of the CONUS. A trough over the West Coast and a trough over the eastern CONUS are forecast to persist. 

Below normal temperatures are most likely across the northwest, north-central,  and northeastern CONUS, due to forecast near to below normal 500-hPa height. Ridging and/or weak positive 500-hPA height anomalies lead to enhanced probabilities of above normal temperature over most of the southern CONUS, with the highest odds of above normal temperatures forecast across Texas, consistent with the consolidation tool. Above normal temperatures are probable for much of Alaska underneath forecast above normal 500-hPa heights during the Week-2 period.

The predicted 500-hPa height pattern and influx of anomalous moisture result in increased chances of above normal precipitation from the Pacific Northwest  extending east into parts of the Northern Plains, the Mississippi Valley, and parts of the Tennessee and Ohio Valleys. Near to above normal precipitation is likely over parts of the Southeast, the eastern Gulf Coast, and the Northeast, consistent with the ERF Autoblend tool. Below normal precipitation is favored  to persist across the central and southern Rockies, the Southwest, Texas during Week-2 due to predicted ridging aloft. There are increases chances of above normal precipitation across much of mainland Alaska , except for the southern coast of Alaska and the Alaska Panhandle, consistent with the consolidation tool.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, due to good agreement between models on the predicted 500-hPa height pattern, offset by some disagreement among the temperature and precipitation forecast tools.    

The next set of long-lead monthly and seasonal outlooks will be released on August 15.

Analogs to the NOAA 6 – 14 Day Outlook.

NOAA normally provides two sets of Analogs.

A. Analogs related to the 5 day period centered on 3 days ago and the 7 day period centered on 4 days ago. “Analog” means that the weather pattern then resembles the recent weather pattern and the recent pattern is used to initialize the models to predict the 6 – 14 day Outlook.

B. There is a second set of analogs associated with the Outlook. It compares the forecast (rather than the prior period) to past weather patterns. I have not been regularly analyzing this second set of information. The first set applies to the 5 and 7 day observed pattern prior to today. The second set relates to the correlation of the forecasted outlook 6 – 10 days out and 8 – 14 days out with similar patterns that have occurred in the past during a longer period that includes the dates covered by the 6 – 10 Day and 8 – 14 Day Outlook. The second set of analogs also has useful information as it indicates that the forecast is feasible in the sense that something like it has happened before. I am not very impressed with that approach. But in some ways both Approach A and B are somewhat similar. I conclude that if the Ocean Condition now is different then the analogs and if the state of ENSO now is different than the analogs that is a reason to have increased lack of confidence in the forecasts and vice versa.

They put the first set of analogs in the discussion with the second set available by a link so I am assuming that the first set of analogs is the most meaningful and I find it so. But NOAA prefers the first set (A) as it helps them (or at least they think it does) assess the quality of the forecast.

Here are today’s analogs in chronological order although this information is also available with the analog dates listed by the level of correlation. I find the chronological order easier for me to work with. It also helps the reader see the impact of the phases of the PDO and AMO which are shown. The first set (A) which is what I am using today applies to the 5 and 7-day observed pattern prior to today.

* I assign values that are consistent with the trend so I am doing some subjective smoothing with respect to the Phases of the AMO and PDO shown in this table. (t) = a month where the Ocean Cycle Index has just changed from a consistent pattern or does change the following month to a consistent pattern.

The spread among the analogs from July 23 to August 19 is 27 days which is wider than last week and suggests the ability to have a bit less confidence in the forecast which NOAA describes as difficulty pinning down the timing of changes. That makes sense. I have not calculated the centroid of this distribution which would be the better way to look at things but the midpoint, which is a lot easier to calculate, and fairly accurate if the dates are reasonably evenly distributed, is about August 5, 2019. These analogs are describing historical weather that was centered on 3 days and 4 days ago (August 1 or August 2. So the analogs could be considered to be slightly out of sync with respect to weather that we would normally be getting right now in that we may be getting weather that is a few days early but it is not significant.

For more information on Analogs see discussion in the GEI Weather Page Glossary. For sure it is a rough measure as there are so many historical patterns but not enough to be a perfect match with current conditions. I use it mainly to see how our current conditions match against somewhat similar patterns and the ocean phases that prevailed during those prior patterns. If everything lines up I have my own measure of confidence in the NOAA forecast. Similar initial conditions should lead to similar weather. I am a mathematician so that is how I think about models.

Including duplicates, there are three El Nino Analogs, four Neutral analogs, and three La Nina Analogs. This suggests that we are in ENSO Neutral now but a bit confusing with with both El Nino and La Nina Analogs.  The pre-forecast analogs this week are supportive of McCabe B which is “More wet than dry, but Great Plains and Northeast are dry”. This is consistent with the NOAA forecast and adds to my confidence in the NOAA forecast. In general, these analogs are more relevant in Fall, Summer, and Spring than in Summer.

include(“/home4/aleta/public_html/pages/weather/modules/McCabe_background_information.htm”); ?>

Historical Anomaly Analysis

When I see the same dates showing up often I find it interesting to consult this list.

A Useful Read

Some might find this analysis which you need to click to read interesting as the organization which prepares it focuses on the Pacific Ocean and looks at things from a very detailed perspective and their analysis provides a lot of information on the history and evolution of ENSO events.

Some Indices of Possible Interest: We should always remember that the forecast is driven by many factors some of which are conflicting in terms of their impacts. Please pay more attention to the graphics than my commentary which does not update on a regular basis once the article is published. The indices will continue to update. I provide these indices as they are important guidelines to the weather. It is in a way looking at the factors that are impacting the weather. There were developed because weather forecasters found them to be useful.

Here is another way of integrating all forecasts into a single graphic.  These forecasts extend out further into the future than the forecasts presented earlier. But they do not show the recent history.  Also, the set of four does not include the AO but instead the WPO so it is not the same but may be useful.

The MJO is an area of convective activity along the Equator which circles the globe generally in 30 to 60 days. The location of the convective activity not only impacts the Equator but also the middle latitudes. Most people are not familiar with the MJO but at certain times it plays an important role Worldwide re weather and for CONUS.

This is the Summary from the weekly NOAA analysis of the MJO.

It is sometimes useful to look at the recent history of the MJO.

The MJO Index (more information can be found here) indicates where the MJO has been and this Hovmoeller Graphic shows this. The Index is shown for the parts of the Equator where the MJO is most usually found.

Forecast Models.

There are a lot of models and I try to read the results from all of them. For access to a variety of models, I refer readers here. This weekly report summarizes things. Here is another useful source of information.

Now the first of the three graphics we typically present which shows where the MJO is now and how it got there. 

This shows the recent history.  MJO is now in Phase 4 but inside the circle of minimum impacts. What next?

And then a forecast.  On this GFS graphic, the light gray shading shows the tracks which fit with 90% of the forecasts and the dark gray shading shows a smaller area that fits with 50% of the forecasts The large dot is the current location.

And then the ECMF forecast.

Then side by side.

The new NOAA combination graphics were too difficult for me so I am not showing the original graphics which do not have NOAA commentary but auto-update.

And we also look at the low-level wind anomalies.

Here is a Hovmoeller version which shows more than two time periods as above but a longer history. Along the bottom which is the current week, you can see the westerlies. The key takeaways are

A. There has been another WWB but no sign so far of another Kelvin Wave.

B The MJO has been active.

Remember that the MJO is one of many influences on the weather.

B. Beyond Alaska and CONUS Let’s Look at the World which of course also includes Alaska and CONUS

It is Useful to Understand the Semipermanent Patterns that Control our Weather and Consider how These Change from Winter to Summer. These two graphics (click on each one to enlarge) are from a much larger set available from the Weather Channel. They highlight the position of the Bermuda High which they are calling the Azores High in the January graphic and is often called NASH and it has a very big impact on CONUS Southeast weather and also the Southwest. You also see the north/south migration of the Pacific High which also has many names and which is extremely important for CONUS weather and it also shows the change of location of the ITCZ which I think is key to understanding the Indian Monsoon. A lot of things become much clearer when you understand these semi-permanent features some of which have cycles within the year, longer period cycles and may be impacted by Global Warming. We are now moving into Mid-August. We should now be starting to leave the Summer Pattern. For CONUS, the seasonal repositioning of the Bermuda High and the Pacific High are very significant.

World Forecasts

1. Today (Source: University of Maine)

2. Short-term set for day six but can be adjusted (BOM – Australia)

3. 8 – 14 Day (NOAA/Canada/Mexico Experimental NAEFS))

4 Tropical  Activity

1.  Forecast for Today (you can click on the maps to enlarge them)

And now precipitation

Additional Maps showing different weather variables can be found here.

2. Forecast for Day 6 (Currently Set for Day 6 but the reader can change that)

World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately, I do not know how to extract the control panel and embed it into my report so that you could use the tool within my report. But if you visit it Click Here and you will be able to use the tool to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. Return to this report by using the “Back Arrow” usually found top left corner of your screen to the left of the URL Box. It may require hitting it a few times depending on how deep you are into the BOM tool. Below are the current worldwide precipitation and temperature forecasts for six days out. They will auto-update and be current for Day 6 whenever you view them. If you want the forecast for a different day Click Here

Again, please remember this graphic updates every six hours so the diurnal pattern can confuse the reader.

Now Precipitation

3. And now we have experimental 8 – 14 Day World forecasts from the NAEFS Model.

First Temperature

Then Precipitation

4. Tropical Hazards.

C. ENSO SUMMARY of Current Status. 

This section is organized into three parts.

1. Current Sea Surface Temperatures (SST)

2. Current Nino 3.4 Readings

3. The Surface Air Pressure Pattern that confirms the state of ENSO.

1. Current and Recent Sea Surface Temperatures (SST)

A major driver of weather is Surface Ocean Temperatures. Evaporation only occurs from the Surface of Water. So we are very interested in the temperatures of water especially when these temperatures deviate from seasonal norms thus creating an anomaly. The geographical distribution of the anomalies is very important. To a substantial extent, the temperature anomalies along the Equator have a disproportionate impact on the weather so we study them intensely and that is what the ENSO (El Nino – Southern Oscillation) cycle is all about. Subsurface water can be thought of as the future surface temperatures. They may have only indirect impacts on current weather but they have major impacts on future weather by changing the temperature of the water surface. Winds and Convection (evaporation forming clouds) is weather and is a result of the Phases of ENSO and also a feedback loop that perpetuates the current Phase of ENSO or changes it. That is why we monitor winds and convection along or near the Equator especially the Equator in the Eastern Pacific.

My focus here is sea surface temperature anomalies as they are one of the two largest factors determining weather around the World. If we want to have a good feel for future weather, we need to look at the oceans as our weather mostly comes from oceans and we need to look at surface temperature anomalies (weather develops from the ocean surface

It is the ocean surface that interacts with the atmosphere and causes convection and also the warming and cooling of the atmosphere. So we are interested in the actual ocean surface temperatures and the departure from seasonal normal temperatures which is called “departures” or “anomalies”. Since warm water facilitates evaporation which results in cloud convection, the pattern of SST anomalies suggests how the weather pattern east of the anomalies will be different than normal.

Current Sea Surface Temperature (SST) Departures from Normal for this Time of the Year i.e. Anomalies

First the categorization of the current Monthly Average SST anomalies.
The Mediterranean, Black Sea, and Caspian Sea	Western Pacific	West of North America	North and East of North America	North Atlantic
The Mediterranean, Black Sea and Caspian Sea are slightly warm The Persian Gulf is warm. .	Very warm northeast of Japan	Waters in Bristol Bay and the Chukchi Sea are extremely warm. Gulf of Alaska  warm Warm offshore of British Columbia Warm in Sea of Cortez and west of Baja.	Hudson Bay Cool to the south but warm west and east. Davis Strait very warm Waters offshore of Nothern East Coast are warm but cool farther out to sea.	North Atlantic quite warm.
Equator	Central Pacific very slightly warm.  Eastern Pacific Cool. ENSO Neutral
Africa	West of Australia	North, South, and East of Australia	West of South America	East of South America
Cool off Somalia	Cool	Cool to the  Southwest Cool to the northeast but offshore.	Cool	Warm 40S to 50S and farther south offshore.

Then we look at the change in the anomalies. The SST anomaly is sort of like the first derivative and the change in the anomaly is somewhat like a second derivative. It tells us if the anomaly is becoming more or less intense.

I am only showing the currently issued version of the NINO SST Index Table as the prior values are shown in the small graphics on the right with this graphic. The same data in graphic form but going back a couple of more years can be found here. The full table of values can be found here. NOAA considers Nino 3.4 shown in the graphic as the best indicator of Equatorial Surface Temperature Anomalies associated with different phases of ENSO. There is a duration requirement to be a recorded El Nino or La Nina but to have El Nino Conditions the Nino 3.4 index needs to be +0.5C or warmer and to have La Nina Conditions the Nino 3.4 Index needs to be -0.5C or cooler.

ENSO Considerations

This graphic brings the Nino 3.4 up to date and is easy to read.

Here is a daily version

Starting with Surface Conditions.

TAO/TRITON GRAPHIC (a good way of viewing data related to the part of the Equator and the waters close to the Equator in the Eastern Pacific where we monitor to determining the current phase of ENSO. It is probably not necessary to follow the discussion below, but here is a link to TAO/TRITON terminology.

And here is the current version of the TAO/TRITON Graphic. The top part shows the actual temperatures, the bottom part shows the anomalies i.e. the deviation from normal.

This may help put the above graphics in focus.

The following graphic

is somewhat similar to the graphic above but it updates every five days not once per week. The date shown is the midpoint for the five-day average. It shows a lot more detail than the above graphic. You can see some water at depth that is anomalously warm. But the depth of the warm anomaly is becoming less and there is cool water below it.

3. The Surface Air Pressure that Confirms the Nino 3.4 Index

And of course, Queensland Australia is the official keeper of the SOI measurements.

SOI = 10 X [ Pdiff – Pdiffav ]/ SD(Pdiff) where Pdiff = (average Tahiti MSLP for the month) – (average Darwin MSLP for the month), Pdiffav = long term average of Pdiff for the month in question, and SD(Pdiff) = long term standard deviation of Pdiff for the month in question. So really it is comparing the extent to which Tahiti is more cloudy than Darwin, Australia. During El Nino we expect Darwin Australia to have lower air pressure and more convection than Tahiti (Negative SOI especially lower than -7 correlates with El Nino Conditions). During La Nina we expect the Warm Pool to be further east resulting in Positive SOI values greater than +7).

D. Putting it all Together.

Weak El Nino Modoki Conditions have peaked and are now transforming to ENSO Neutral.

E. Relevant Recent Articles and Reports

Weather in the News

Nothing to report

Weather Research in the News

Nothing to Report

Global Warming in the News

Nothing to report

Useful Reference Information

Understand How the Jet Stream Impacts Weather

include(“/home4/aleta/public_html/pages/weather/modules/Jet_Streak_Four_Quadrant_Analysis.htm”); ?>

include(“/home4/aleta/public_html/pages/weather/modules/MJO_and_ENSO_Interaction_Matrix.htm”); ?>

Standard Pressure Levels

include(“/home4/aleta/public_html/pages/weather/modules/Standard_Pressure_surfaces.htm”); ?> include(“/home4/aleta/public_html/pages/weather/modules/Table_of_Contents_for_Part_II.htm”); ?> include (“/home4/aleta/public_html/pages/weather/modules/AO_NAO_PNA_MJO_Background_Information.htm”); ?>