Written by Sig Silber

HEADLINES (Updated 4:48 pm EDT) –

“- There is a slight risk of severe thunderstorms and slight risk of excessive rainfall over parts of the Lower Great Lakes and parts of the Eastern Ohio Valley

– There is a slight risk of severe thunderstorms over parts of the Upper Mississippi Valley/Upper Great Lakes into the Central Plains

– There is a slight risk of excessive rainfall over parts of the Middle/Lower Mississippi and parts of the Central/Southern Plains”

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 402 PM EDT Thu Jul 16 2020

Valid 00Z Fri Jul 17 2020 – 00Z Sun Jul 19 2020

…There is a slight risk of severe thunderstorms and slight risk of excessive rainfall over parts of the Lower Great Lakes and parts of the Eastern Ohio Valley…

…There is a slight risk of severe thunderstorms over parts of the Upper Mississippi Valley/Upper Great Lakes into the Central Plains…

…There is a slight risk of excessive rainfall over parts of the Middle/Lower Mississippi and parts of the Central/Southern Plains…

A front draping across the Lower Great Lakes/Ohio Valley to the Southern Plains northward to the Northern High Plains will be the main focus for severe thunderstorms and areas of heavy rainfall expected to impact by the Lower Great Lakes/Ohio Valley Thursday evening into Friday morning. Meanwhile, a trough of low pressure moving across the Northern Plains into the Upper Midwest. The boundary will trigger showers and thunderstorms over the region through to Friday morning. Heavy rain associated with the thunderstorms will mainly localized scattered flash flooding over parts of the area through Friday morning.

As the next upper trough from the Pacific Northwest approaches, the Northern Plains will be under an increasing threat of severe thunderstorms on Friday ahead of a warm front and a developing low pressure system.

The excessive heat across the South has moderated to more tolerable levels but heat advisories are still in effect today across the interior sections of the lower Mississippi Valley. Finally, some monsoonal showers and thunderstorms are expected to linger over the central and southern Rockies into the weekend.

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

This loop showing the prior 40-hours provides perspective. We have not yet figured out how to make this loop update but it is still useful for a few days. An updated version and some other views can be found here.

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Day 3 – 7 Hazards

Hazards:

– Heavy rain across portions of the Northern/Central Plains and the Upper/Middle Mississippi Valley, Sun-Mon, Jul 19-Jul 20.

– Flooding occurring or imminent across portions of the Upper Mississippi Valley and the Northern Plains.

– Flooding likely across portions of the Middle Mississippi Valley.

– Excessive heat across portions of the Central Plains, the Upper/Middle Mississippi Valley, the Great Lakes, the Ohio Valley, and the Central Appalachians, Sun, Jul 19.

– Excessive heat across portions of the Middle/Lower Mississippi Valley, the Ohio Valley, the Tennessee Valley, and the Southeast, Sun-Mon, Jul 19-Jul 20.

– Excessive heat across portions of the Mid-Atlantic, the Northeast, and the Central Appalachians, Sun-Wed, Jul 19-Jul 22.

– Much above normal temperatures across portions of the Great Lakes, the Central Appalachians, the Ohio Valley, the Mid-Atlantic, and the Northeast, Sun, Jul 19.

– Heavy rain across portions of the Alaska Panhandle and mainland Alaska, Sun-Mon, Jul 19-Jul 20.

Detailed Summary:

The medium range period (Sunday, July 19 – Thursday, July 23) will continue to feature a summer-like pattern with heat across the Southwest into the central/eastern U.S. as high pressure persists south of the jet stream located across the northern states. Hot temperatures combined with high dewpoints will lead to high heat indices over much of the Mississippi Valley, the Tennessee/Ohio Valleys, and Southeast early in the week. Warm overnight lows are expected as well, exacerbating the heat threat. The heat in the central U.S. is expected to subside somewhat as a front pushes through Sunday, but heat indices over 105 could remain across the Lower Mississippi and Tennessee Valleys through Monday, but these high heat indices look to become more isolated later in the week. Additionally, high heat indices over 100, even approaching 110 in some places, are forecast across the Mid-Atlantic region to the New York City area for the first half of next week, leading to an Excessive Heat area there. Farther north, the Lower Great Lakes and Northeast can expect temperatures several degrees above average, especially Sunday when highs should be in the 90s. The Desert Southwest, southern Texas, and the Florida peninsula should also remain hot, but all those areas are around or just a few degrees above normal for this time of year. The main consistent spot where temperatures could be below normal is the Northern Plains on the cool side of a front.

Rain and thunderstorms are possible in the vicinity of fronts moving through north-central and eastern parts of the country through the period. One potential focus for organized convection early next week is a frontal boundary forecast to stall over the Middle Mississippi Valley and Central Plains. Heavy rain could occur as copious amounts of moisture flow into this boundary. The exact placement of the heavy rainfall amounts will change depending on the positioning of the front. Rain and thunderstorms are also expected along the Eastern Seaboard, but model guidance is not currently consistent on areas where the rain could focus to become heavy. Southwestern Florida could see heavy rainfall around Tuesday, but heavy amounts may remain offshore. Another area to watch for heavy rain potential is eastern North Carolina from midweek onward, but model guidance continues to vary.

Over Alaska, moisture streaming ahead of a low pressure system tracking across the southern coast could lead to heavy rainfall for the Panhandle early next week. Showers are also likely over interior Alaska through the period, but organized heavy rainfall is not expected there. Some rain may also spread into the Aleutians around midweek as another low pressure system moves across. A cold upper-level trough will lead to cooler than normal conditions across much of the state, but especially over the North Slope, where high temperatures could be as much as 30 degrees below average through Tuesday, and low temperatures could be below freezing.

(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.

We will update the above map weekly but more frequent updates can be obtained here.

There is not much snow left.

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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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