Live: Severe Weather Events Issued On August 26 2019 - Monday And Tuesday

Written by Sig Silber

Updated at 5:30 PM EDT August 26, 2019 to reflect the latest update on Dorian.

Focal Points for Monday and Tuesday. Hazards for Days 3 and 7 out to August 30 are shown in the body of the report. The Hazards list will not update until Monday afternoon.

…Well above-normal to record-breaking heat expected across the Southwest and southern Plains on Monday…
…Temperatures to continue climbing across northern California and the Pacific Northwest Monday and Tuesday…

…Strong to severe storms expected across portions of the northern Plains late Sunday into early Monday…
…Strong to severe storms expected across portions of the mid Mississippi valley, Kansas and Oklahoma Monday afternoon and evening…

Looking out 3 to 7 Days

– Heavy rain across portions of the south-central Plains into the Ozarks, and from the upper Midwest to the upper Great Lakes, Mon-Tue, Aug 26-Aug 27.
– Heavy rain across portions of the central Plains, Fri, Aug 30.
– Heavy rain along the Outer Banks of North Carolina, Mon, Aug 26.
– Flooding occurring or imminent across portions of the Northern Plains.
– Flooding likely across portions of the Northern Plains.
– Excessive heat across portions of the interior valley of southern California, Mon-Wed, Aug 26-Aug 28.
– Excessive heat across portions of the southern High Plains, Mon, Aug 26.
– Much above normal temperatures across portions of western Oregon, Tue-Wed, Aug 27-Aug 28.
– Heavy rain across the southern portion of the Alaska Panhandle, Tue, Aug 27.

This article provides continuous updates for a variety of Weather and Weather-Related Threats. Pay attention to how severe weather may impact where you live or travel. For a location of interest on any of these maps, click the map to see the details – perhaps a very detailed map and appropriate text information. These are “Live” maps and continually update. Please pay attention to the Mesoscale Events maps — Mesoscale Events are potentially life-threatening situations.

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Today is August 26, 2019. If you are reading this article later than this date, there may be a later version which you can access by clicking here and selecting the latest version of this article from the top of the Directory and clicking on that. This article is “Live” and the current day graphics will update continually as will the Day 2 graphics, the Day 3 Graphics, the Day 3 – 7 graphics and the week – 2 graphics. So the graphics always update but the latest version of the article has my updated commentary and updated NOAA discussions when we update those which may be daily or every two days depending on how fast conditions are changing. So if you have an older version, e.g. from an email you received yesterday, the graphics are always current but if you want to be sure you have the most current discussions, click here and then click again to go to the most recently published version. It is our goal to provide the most current information and discussion practical.

Possible Hurricane.

We will be providing the Discussions now and updating it at least daily. If the storm intenisifies further we will increase update frequency in coming days. For those who need the most recent update, one can find it here.

Tropical Storm Dorian Discussion Number 10 NWS National Hurricane Center Miami FL       AL052019 500 PM AST [Editor’s Note: Same as EDT] Mon Aug 26 2019
Dorian’s convective pattern has waxed and waned this afternoon due to intrusions of dry mid-level air while the upper-level outflow pattern has continued to expand and become more symmetrical. Although the inner-core convection has decreased recently, a recent burst of strong convection with cloud tops colder than -80C has redeveloped just north of the low-level center. The initial intensity remains at 50 kt based on a an average of satellite intensity estimates ranging from 45 kt to 61 kt from TAFB, SAB, and UW-CIMSS SATCON and ADT. An Air Force Reserve reconnaissance aircraft is scheduled to investigate Dorian by 0000 UTC this evening, and will provide a better estimate of the cyclone’s intensity.
The initial motion is west-northwestward or 290/12 kt. There is no significant change to the previous forecast track or reasoning. The latest NHC model guidance remains in very agreement that Dorian will move west-northwestward across the central Lesser Antilles tonight and into the northeastern Caribbean Sea on Tuesday as the cyclone moves around the edge of the Bermuda-Azores ridge located well to the north. On Wednesday, Dorian should turn northwestward into a small weakness in the ridge, allowing the tropical cyclone to pass near or between western Puerto Rico and the eastern Dominican Republic. By late Thursday and Friday, the ridge is forecast to build back in as an upper-level trough lifts out to the north, causing Dorian to turn back toward the west-northwest in the vicinity of the central Bahamas. The new official forecast track is just an extension of the previous one since the latest model guidance, especially the consensus models, are tightly packed around the previous track forecast.
The intensity forecast remains something of an enigma. The majority of the environmental conditions support at least steady strengthening, with the main hindrance being the very dry mid-level air surrounding the cyclone and occasionally being entrained into Dorian’s inner-core region. The small but robust circulation should continue mix out the brief dry air intrusions, but when an eyewall will form is still uncertain. Given that Dorian will be moving into the convective maximum period later tonight, the intensity forecast still calls for Dorian be near hurricane strength when it passes through the Windward Islands. Interaction with Hispaniola and possibly Puerto Rico should result in some weakening in 72-96 hours, followed by restrengthening on days 4 and 5 when Dorian will be moving over the very warm waters in the Bahamas in low shear conditions. Most of the global models along with the statistical-dynamical SHIPS and LGEM intensity models are now showing pronounced strengthening while Dorian is moving near or through the Bahamas, so the official forecast shows a significant change to the previous one at 96 and 120 hours. However, confidence in the intensity forecast at days 4 and 5 is very low given the uncertainty about how much of Dorian’s core will interact with Hispaniola.
Key Messages:
1. Dorian is expected to bring tropical storm conditions to portions of the Lesser Antilles tonight and Tuesday, where tropical storm watches and warnings are in effect. Hurricane conditions are possible in St. Lucia, where a Hurricane Watch is in effect. Rainfall of 3 to 8 inches is expected from Martinique to St. Vincent, including Barbados, with isolated totals as high as 10 inches possible.
2. Tropical storm conditions are possible in Puerto Rico on Wednesday, where a tropical storm watch has been issued. Rainfall of 2 to 4 inches with maximum totals of 6 inches are possible across Puerto Rico and St. Croix.
3. Watches will likely be issued for portions of Hispaniola tonight or Tuesday, as the threat of wind and rain impacts continues to increase.
4. While uncertainty is high, wind and rain impacts are possible in the Bahamas and Florida later this week and this weekend. Residents in these areas should monitor the progress of Dorian and ensure that they have their hurricane plan in place.
FORECAST POSITIONS AND MAX WINDS
INIT 26/2100Z 12.7N 58.8W   50 KT 60 MPH
12H 27/0600Z 13.4N 60.5W   55 KT 65 MPH
24H 27/1800Z 14.5N 62.6W   60 KT 70 MPH
36H 28/0600Z 15.7N 64.6W   65 KT 75 MPH
48H 28/1800Z 17.1N 66.7W   70 KT 80 MPH
72H 29/1800Z 20.1N 70.2W   50 KT 60 MPH
96H 30/1800Z 23.0N 73.8W   55 KT 65 MPH
120H 31/1800Z 25.5N 78.0W   60 KT 70 MPH

Now, the Day One and Two CONUS Forecasts: These Maps Update Daily.

Day One CONUS Forecast	Day Two CONUS Forecast

These graphics update and can be clicked on to enlarge. You can see where the weather will be

This is the time of the year we pay special attention to Tropical Events

First looking at the Atlantic and the Gulf of Mexico

We will be providing the Discussions now but not updating it every six hours. For those who need the most recent update, one can find it here.

Switching to the Eastern Pacific

And the Central Pacific.

Central Pacific Storms

Updates on individual named storms can be obtained here.

And the Western Pacific

Here is the current daily Short-Term Forecast

August 25, 2019 WPC p.m. short term forecast

Click here for updates to this NWS/WPC Discussion.

Looking out farther out. This report does not update during weekends.

August 23, 2019 Day 3 - 7 Hazards.

Click here for updates of the Day 3 -7 Hazards forecast.

The following map shows where mesoscale events are occurring or forecast. If you do not see any areas highlight on this map than there are no mesoscale events taking place or forecast. A mesoscale event is a very serious situation for a very small area and detailed information is provided for these events when they occur or are forecast. If a mesoscale event is shown, click on the map and more detail on the event will be shown.

Two different part of the NWS issue this map and they are not always in agreement although they are pretty close. They (Norman Oklahoma and College Park Maryland) issue the alerts when they realize the need so it is best to look on both maps and click one or both if you see areas highlighted.

This next map showing where “Headlines” have been issued for convection (and an animation of the recent movement of storms) should update and you should be able to click on to get additional details but if it does not update when you click on it, click here.

For the Day 2 Outlook click here. For Day 3, click here. For Days 4 – 8 click here. An explanation of the risk codes used can be found here.

There is a slight difference between convection and thunderstorms. The below map shows where “Headlines” have been issued for Thunderstorms. You should be able to click on the map to get additional details but if it does not update, you can click here.

The map below shows the current wildfire risk which becomes more significant as we move into Summer. When you click on this image it takes you to the SPC Fire Warning Page and you get a set of maps for Days 1, 2, 3 – 8, etc. You can then click on those for more detailed information. The map is a bit blurry as I tried to make it a bit larger than the map provided by NOAA but should be able to see where the current wildfire risks are. But if you click on this map, you will get to see three maps that show the risk for different time periods.

Or for the Day 2 Fire Outlook click here. For the Day 3 – 8 Fire Outlook click here.

Now the Day 3 – 7 Hazards Outlook

The orange and red outlined areas are what is of most concerning of the forecasted Day 3 – 7 Hazards. This graphic does not update during the weekend. There is a discussion that goes with this graphic and you can access that discussion here.

The following is provided to help the reader relate the maps to how NWS will describe an area of the U.S.

Now to our More Detailed Report

This graphic is about 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.

In and of itself Atmospheric Rivers are not a definitive predictor of extreme weather but it shows where concentrated “rivers” of moist air are forecast to be impacting North America and that is part of the equation for severe weather.

Mostly I see Ivo

This view shows a fairly low level of activity. But Ivo needs to be watched. It is weakening but moving closer to shore albeit in Mexico.

This view provides a better view of the Northeast, the Antilles and also Europe.

Since the AR imagery was not working recently, we added some substitute images which I will leave in for now. Enjoy.

This is a little different than the AR as it shows all Liquid Water not just thick streams of moisture. Thus it shows more activity than the AR graphic. But if you try to line the two up, you will easily be able to see where the AR is on this graphic. The gray areas are where different satellite images are pieced together to provide a wide view.

And the East Coast

These are a little different then the AR imagery as this shows clouds and AR shows streams of moisture in the atmosphere.

You have to really study this graphic to see the outline of CONUS. Lots of activity around Florida.

Here is the web site where this set of images can be found.

500 MB Mid-Atmosphere View

The map below is the mid-atmosphere 3–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.

It is a fairly zonal pattern. The H shown stands for High but it could also stand for Hot. The Four Corners High? It is certainly not in the best place for it to be to ramp up the Monsoon but the QPF graphics show some but not much moisture for New Mexico.

As of this evening, we see for Day 7 a clear North/South Divide. It will be Hot south of that boundary.

Notice the change in the location of the Four Corners High.

We discuss the various patterns of the Monsoon in our Monday article which can be accessed by going to the Directory here and looking for the most recent version of the Intermediate-Term Forecast Article.

Day 3 Above, 6 Below	Day 4 Above,7 Below	Day 5 Above.

The above is an advanced look. Our most recent 25 Day Intermediate-Term Forecast might provide additional information. The URL for that report changes each Monday so you can find it on the Econintersect.com website or consult the Directory which can be accessed here.

Here are the precipitation forecasts. First the cumulative for Days 1 – 3

This pretty much corresponds to the discussion above.

Then cumulative for Days 1 – 5

This represents five days of precipitation rather than three days as shown in the earlier graphic.

Then cumulative for Days 1 – 7

The areas that have cumulative seven-day precipitation increase. You can see where QPF is accumulating.

Florida and Eastern Oklahoma and points north are forecast to be active.

Remember the commentary is generally as of last Night unless updated which is indicated in the lede paragraph. The graphics auto-update so the commentary may not be up-to-date beyond the initial date of publication.

We have to start worrying about heat being a hazard.

The Southwest is where the temperature will really be turned up. We now see some plus 110F temperatures forecast. It is becoming late August so it is less likely to have such extreme temperatures now, just hot. But the heat is widespread.

Looking ahead to next week.

Usually, nothing shows in this graphic for the following week as it is usually too far out to be forecasting severe weather. But this graphic auto-updates.

Current watches, warnings, and advisories issued by the agencies of the National Weather Service. Hazards should show up in the various maps but the below links will take you to all outstanding watches and warnings in each category which may include some categories not covered in the various maps or difficult to find. So if there is a category of interest, click on the appropriate link below.

Below you will see a number of different maps which are updated in real-time, making this a “live” report. If a part of one or more of the maps shows an area that is highlighted, you can click on it and get the full current report. By having the reader click on these active situations rather than having GEI do so, you will not miss any events in which you might have an interest and which we had not noticed and the page will not get cluttered with warnings, etc that have since expired.

Our focus here are events that are likely to last in the range of six hours but there can be longer or shorter events that are addressed by the Storm Prediction Center which is the main source of the information in this article. Long-term major events like a Hurricane are more likely to be in a separate article. But that may not always be the case. Since in general, all the links on this page transfer you into the NOAA system, in order to get back into this article you need to either close the tab to which you were transferred or click back on the tab that has this article.

Convective Outlooks
Live Warning Maps which If Severe Weather is Shown can be Clicked on to get more detail about these events. If there is a current warning shown on the map, click on the map for additional information related to the event.	These maps are updated as risks are identified.
This is the current graphic showing any mesoscale discussions (MD’s) which are in effect over the contiguous United States. Please read the description of the purpose of our MD’s for further information. Details on all valid MD’s may be found on our Current Mesoscale Discussions page.
This is today’s forecast for organized severe thunderstorms over the contiguous United States. Please read the description of the risk categories for further information. You may find the latest Day 1 Outlook available as well as all Outlooks issued today online.	Today’s Outlook

This is tomorrow’s forecast for organized severe thunderstorms over the contiguous United States. Please read the description of the risk categories for further information. The latest Day 2 Outlook is available as well as all Outlooks that have been issued today.	Tomorrow’s Outlook

This is the day after tomorrow’s (day 3) forecast for organized severe thunderstorms over the contiguous United States. Please read the description of the risk categories for further information. The latest Day 3 Outlook is available as well as all Outlooks that have been issued today.	Day 3 Outlook

This is the day 4-8 forecast for organized severe thunderstorms over the contiguous United States. The latest Day 4-8 Outlook is available as well as all Outlooks that have been issued today. Note: A severe weather area depicted in the Day 4-8 period indicates a 30% or higher probability for severe thunderstorms (e.g. a 30% chance that a severe thunderstorm will occur within 25 miles of any point).	Day 4-8 Outlook

The Thunderstorm Outlooks depict the probability of thunderstorm across the contiguous United States in 4 or 8 hour time periods. The probabilistic forecast directly expresses the best estimate of a thunderstorm occurring within 12 miles of a point. The three probabilistic forecast thresholds are 10, 40, and 70 percent.	Thunderstorm Outlook

Fire Weather Outlooks
This is today’s forecast for organized wildfires over the contiguous United States. Please read the description of the risk categories for further information about this product.	Today’s Outlook

This is tomorrow’s forecast for organized wildfires over the contiguous United States. Please read the description of the risk categories for further information about this product.	Tomorrow’s Outlook

This is day 3-8 forecast for organized wildfires over the contiguous United States. Please read the description of the risk categories for further information about this product.	Day 3-8 Outlook