Written by Sig Silber

HEADLINES (Updated 3:55 PM and 6:68 PM EDT) –

– Midsummer heat found throughout the northern and central Plains

– Elevated fire weather concerns continue across the northern Rockies and northern Great Basin

– Isolated chances for severe thunderstorms and flash flooding possible for the Lower Great Lakes and Northeast today

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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For those interested in longer-term forecasts, we just published the new NOAA Seasonal Outlook and it can be accessed here.

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CONUS Focal Points

Short Range Focal Points

Short Range Forecast Discussion NWS Weather Prediction Center College Park MD

125 PM EDT Tue Jul 20 2021

Valid 00Z Wed Jul 21 2021 – 00Z Fri Jul 23 2021

…Midsummer heat found throughout the northern and central Plains…

…Elevated fire weather concerns continue across the northern Rockies and northern Great Basin…

…Isolated chances for severe thunderstorms and flash flooding possible for the Lower Great Lakes and Northeast today…

A persistent, but gradually weakening upper-level ridge over the central U.S. will provide a continuing stretch of above average temperatures across the northern and central Plains through at least midweek. Widespread high temperatures into the upper 90s and low triple digits are forecast here, which is slightly lower than what was felt yesterday. These warm temperatures and lack of rain will likely worsen the ongoing severe to exceptional drought found throughout the region. Excessive Heat Warnings remain in effect across eastern Montana.

Farther west, the combination of extreme drought, gusty winds, and thunderstorms will produce fire weather concerns for the northern Great Basin and northern Rockies through Thursday. Thunderstorms ahead of an advancing cold front entering the Pacific Northwest today are likely to produce little rainfall, but lightning could reach the dehydrated terrain and spark new wildfires, with drying expected behind a modified Pacific cold front moving slowly through the region.

The areas with the greatest chances of seeing summer storms include the Northeast, Lower Great Lakes, Southeast, and Southwest. A cold front crossing the Lower Great Lakes with thunderstorms in tow are forecast to shift into New England and coastal sections of the Northeast tonight and Wednesday; some storms could be severe tonight.

For the Southeast and Gulf Coast States, a lingering frontal boundary bisecting the region will be the focus for additional rounds of slow-moving thunderstorms today before lifting slowly northward Wednesday and Thursday. The main concern with these storms will be associated with heavy rainfall and scattered flash flooding tonight, with the threat fading in coverage and intensity on Wednesday and Thursday.

The Southwest Monsoon is expected to continue with scattered chances of thunderstorms through much of this week. As a result, isolated instances of flash flooding will remain a possibility between the Southwest and central Great Basin, especially on Thursday.

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 40 hour animation and some other views can be found here

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Day 3 – 7 Hazards

Valid Friday July 23 2021 – Tuesday July 27 2021

Hazards:

– Heavy rain across portions of the Southern Rockies, the Central Great Basin, and the Southwest, Fri-Tue, Jul 23-Jul 27.

– Heavy rain across portions of the Great Lakes, Sat, Jul 24.

– Flooding occurring or imminent across portions of the Central Plains, the Middle Mississippi Valley, the Southern Plains, and the Ohio Valley.

– Flooding occurring or imminent across portions of the Central Plains, the Middle Mississippi Valley, and the Southern Plains.

– Flooding likely across portions of the Central Plains and the Middle Mississippi Valley.

– Excessive heat across portions of the Middle Mississippi Valley, the Lower Mississippi Valley, the Southern Plains, the Ohio Valley, and the Tennessee Valley, Sun-Tue, Jul 25-Jul 27.

– Excessive heat across portions of the Northern Plains, Thu, Jul 23 and Mon, Jul, 26.

– Excessive heat across portions of the Central Plains, the Upper Mississippi Valley, and the Northern Plains, Fri, Jul 23 and Mon, Jul26.

– Excessive heat across portions of the Central Plains and the Middle Mississippi Valley, Mon-Tue, Jul 26-Jul 27.

– Much above normal temperatures across portions of California, the Central Great Basin, the Pacific Northwest, the Northern Rockies, and the Northern Great Basin, Sat-Mon, Jul 24-Jul 26.

– Much above normal temperatures across portions of the Central Plains, the Northern Plains, the Great Lakes, the Northern Rockies, the Middle Mississippi Valley, the Upper Mississippi Valley, and
the Southern Plains, Fri-Mon, Jul 23-Jul 26.

Detailed Summary:

Heavy rain associated with the Monsoon in the Southwest as well as hot weather across the Central/West U.S. remain the primary headlines for the medium-range hazards forecast period (Friday, July 23 – Tuesday, July 27). Additional moderate to heavy rain is expected to spread from Northern Tier into the Northeast this weekend into next week ahead of a frontal system.

Over the Desert Southwest, daily heavy rain associated with the Southwestern Monsoon is expected to continue through the entirety of the forecast period, with a steady influx of moisture progressing slowly northward. Locally enhanced rainfall is possible over the region ahead of a weak upper-level low retrograding westward, with the usual caveat of uncertainty regarding the timing and placement of weak features at the medium range. Regardless of shortwave influences, the persistence of deep moisture over the region through the next week supports a broad heavy rain footprint over the area. Moreover, areas containing inundated soils from previous rain or burn scars will be especially sensitive to heavy rainfall. Accordingly, the Heavy Rain area was expanded over much of Arizona into South Utah to address this possibility.

More excessive heat and above average temperatures are on the way for the interior Pacific Northwest and Central U.S. as a high pressure center migrates into the Central Plains from the Gulf of Mexico later this weekend. Meanwhile, an upper ridge will take shape over the Great Basin in the wake of a closed low over Central Canada. High temperatures are forecast to remain 5-10 degrees above average throughout the Much Above Normal Temperatures areas, generally in the mid-upper 90’s.

Excessive Heat is likely over the Dakotas on Friday as maximum heat indices approach 110 degrees. Heat indices abate somewhat over the Northern Plains as a cold front ushers in dry continental air this weekend, but high temperatures will generally remain above average in the 90’s. One more round of Excessive Heat is possible over the Northern Plains on the 26th as Gulf moisture returns north and heat indices hit 100-105.

Further south in the Central/Southern Plains, the persistent high pressure center overhead combined with the tropical airmass will make for unpleasant heat to begin next week. In the Central Plains, several days in a row of heat indices hitting 105 combined with appreciable ensemble probabilities of low temperatures exceeding 80 degrees prompted the addition of Excessive Heat in the area through the 27th. Over the Ozarks, the Excessive Heat area was expanded until the 27th to correspond with the forecast 110 degree heat index area.

Ahead of the aforementioned front in the Great Lakes, thunderstorms producing moderate to locally heavy rainfall are possible on Saturday before the front pushes east by Sunday. Some higher rain amounts are possible over the Northeast/New England early next week, but uncertainty regarding the timing and placement of the front and associated frontal waves precludes a Heavy Rain area at this time.

For Alaska, rain showers are expected for the eastern Kenai Peninsula on Saturday and east into the Panhandle on Saturday and Sunday ahead of a storm system over the Gulf of Alaska. There is reasonable convergence between guidance for marginally hazardous rainfall totals, in the area, but dry antecedent conditions will limit any impact from the rain. Additionally, generally below normal temperatures are expected across the mainland through the period, particularly in the Far North. These temperatures are not expected to be hazardous at this time.

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 snow coverage in the Fall

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Drought Coverage

We include drought information in this section.

More information can be found here.

July Drought Outlook.

Seasonal Outlook Issued May 20, 2021

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Tropical Events

Atlantic and Gulf of Mexico

The Eastern Pacific

The Central Pacific

Updates on individual named storms can be obtained here.

And the Western Pacific

Weekly 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

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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