Written by Sig Silber

HEADLINES (Updated 6:01 pm EDT) –

“– There is a Moderate Risk of severe thunderstorms over portions of the Midwest

– Above normal temperatures to continue across the Northeast

– Elevated fire weather conditions expected in portions of the Northwest, Rockies and Great Basin”

This article provides continuous updates for a variety of Weather and Weather-Related Threats as well as a general weather forecast. These are “Live” maps that continually update. Please pay attention to the Mesoscale Events maps — Mesoscale Events are potentially life-threatening situations.

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CONUS Focal Points

Short Range Focal Points

Short Range Forecast Discussion NWS Weather Prediction Center College Park MD – 404 PM EDT Mon Aug 10 2020

Valid 00Z Tue Aug 11 2020 – 00Z Thu Aug 13 2020

…There is a Moderate Risk of severe thunderstorms over portions of the Midwest…

…Above normal temperatures to continue across the Northeast…

…Elevated fire weather conditions expected in portions of the Northwest, Rockies and Great Basin...

The Storm Prediction Center has issued a Moderate Risk for severe thunderstorms for portions of the Midwest. An ongoing derecho, currently producing widespread damaging winds is expected to continue to move rapidly east across portions of southern Wisconsin and northern Illinois, including the Chicago Metro area this afternoon. Expect strong to severe storms to continue farther east into lower Michigan and Indiana, while extending south into central Illinois this evening before dissipating overnight.

These storms are developing ahead of a cold front that is forecast to gradually push east from Great Lakes into the Northeast, while settling south into the mid Mississippi and Ohio valleys over the next couple of days. Ahead of the front, above normal temperatures are expected to continue into midweek, with Heat Advisories in effect for portions of the Northeast, including the I-95 corridor from New York to southern Maine. Expect the approaching cold front to bring more widespread shower and thunderstorm coverage across the Northeast and Mid Atlantic late Tuesday into Wednesday, while knocking down temperatures by midweek.

A pair of cold fronts producing windy conditions, but little precipitation, will support elevated to critical fire weather conditions tomorrow across portions of the Northwest, northern Rockies and Great Basin. A Fire Weather Watch is in effect for Tuesday for portions of eastern and central Washington to northwestern Nevada and northern California. Red Flag Warnings are also in effect on Tuesday for portions of central and western Montana, central and western Wyoming, southern Idaho and northern Utah.

We try to keep this up to date but if is not you can find the updated version here.

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.

Thunderstorm Risk

This should play out something like shown in this 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 two maps below break it down by day and may be easier to read.

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

During the winter much of our weather originates in the Pacific. That is why we pay attention to the near-term history of storms arriving.

Temperature

A version that shows a 20 hour animation and some other views can be found here OR SIMPLY CLICK ON THE IMAGE.

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Day 3 – 7 Hazards

Hazards:

– Heavy rain across portions of North Dakota into northern Minnesota, Thu-Fri, Aug 13-Aug 14.

– Heavy rain across portions of the Mid-Atlantic into the central Appalachians, Thu-Sun, Aug 13-Aug 16.

– Flooding occurring or imminent across portions of the Middle Mississippi Valley.

– Excessive heat across portions of the Desert Southwest, Fri-Mon, Aug 14-Aug 17.

– Excessive heat across portions of the southern Plains, Thu-Fri, Aug 13-Aug 14.

– Excessive heat across portions of the lower Mississippi Valley, Sat-Sun, Aug 15-Aug 16

– Much above normal temperatures across portions of the southern High Plains, Thu-Fri, Aug 13-Aug 14.

– Heavy rain across much of the Alaska Panhandle, Sun-Mon, Aug 16-Aug 17.

Detailed Summary:

The medium range period (Thursday, Aug. 13 to Monday, Aug. 17) will feature a slow-moving front stretching across the eastern U.S. Models are showing increasing support for heavy rain to fall over portions of the Mid-Atlantic into the central Appalachians through the medium range period. In addition, remnant energy associated with a decayed front could be reinvigorated as a low pressure center possibly forms near the Carolina coast and then tracks toward the Outer Banks. The National Hurricane Center has begun watching for any signs of tropical cyclone formation regarding this system. In any event, the presence of the slow-moving front together with the alleged development of the new low pressure system will keep a good chance of showers and thunderstorms for the Mid-Atlantic for late this week into the weekend. It appears that daytime heating will enhance the thunderstorm chances each day during the late afternoon to early evening hours while lulls in the precipitation will tend to occur at night. By next Monday, the low pressure system should be moving off the Mid-Atlantic coast but a cold front moving in from the Ohio Valley may bring some heavy rainfall into southern New England.

A cold front dipping into the northern Plains on Thursday will possibly interact with a low pressure wave associated with another frontal system just to the south. This will increase the threat of heavy rainfall associated with strong thunderstorms across eastern North Dakota into northern Minnesota Thursday and Friday. The threat of heavy rain is expected to decrease as the front moves into the Great Lakes during the weekend.

Meanwhile, the upper-level ridge over the Southwest is forecast to strengthen and move westward during the medium-range period. This will increase the threat of excessive heat in the desert areas where afternoon temperatures of 115 degrees or higher are forecast from Friday through next Monday, with record daily high temperatures likely by Sunday. Temperatures in the southern High Plains will also soar well into the 100s on Thursday and Friday under the strong upper ridge. Humidity will be sufficiently low to keep the heat from being too oppressive there. On the other hand, high humidity across the southern Plains into the lower Mississippi Valley will allow heat indices to possibly soar above 105 degrees in the afternoon, where a couple areas of Excessive Heat are highlighted.

As for Alaska, models are showing increasing support for a fairly vigorous occluded cyclone to approach and make landfall over southeastern part of the state during the weekend and into next Monday. Therefore, heavy rain will appear possible next Sunday to Monday for the Panhandle. Elsewhere, rather warm high temperatures into the 70s are forecast for southern Alaska as the next occluded cyclone tracks into the Aleutians.

(This is updated only during the week) Note the first list is weather highlights, this list is hazards. Not sure there is that much of a difference but they come from two different parts of NOAA. The Day 3 – 7 Hazards List does not update on weekends. But it is still useful as it remains valid for the period of time it covers. Of course, all forecasts are subject to change. Later we show a map of the hazards. Perhaps we should show them together.

Click here for the latest complete Day 3 -7 Hazards forecast which updates only on weekdays. It includes the full discussion which I do not update in this article but only present the highlights.

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Ski Snow Reports

We will resume more detailed coverage when the summer is over. During the summer we might add some drought information in this section.

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Tropical Events

This is now beyond the time of the year we pay special attention to Tropical Events other than the Western Pacific.

So I am replacing the large with three small maps but you can click on them to get larger versions. Even though they are small maps you should be able to tell if there is activity and If I see activity I will make the map where there is activity full size.

the Central Pacific.	the Eastern Pacific	the Atlantic and the Gulf of Mexico

Updates on individual named storms can be obtained here.

And the Western Pacific

Week Tropical Forecast

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Intermediate-Term Weather Forecast

And shifting to the Alaska and CONUS Intermediate-Term Weather Forecast showing from left to right, Days 1- 5, 6 – 10, 8 – 14 and Weeks 3 – 4 You can click on these maps to have them enlarge, there are larger versions in the Addendum (More Weather the link is shown at the end of this section, and there are larger versions of these maps in the Addendum. Also, the discussions that go with these forecast maps can be found here (first two weeks) and here (Weeks 3 and 4).

First Temperature

And then Precipitation

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Mesoscale Events

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 parts 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.

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.

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Now the Day 3 – 7 Hazards Outlook Maps

The orange and red outlined areas are what is 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.

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Now to our More Detailed Weather 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.

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.

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

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

Then cumulative for Days 1 – 5

Then cumulative for Days 1 – 7

Now we look at the forecast for the Maximum Temperature three days out.

Looking ahead to next week.

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Additional Tools to Obtain Watches and Warnings

Below you will see a number of different maps that 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 is 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.

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.
Convective Outlooks
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 thunderstorms 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

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