Written by Sig Silber

HEADLINES (Updated 4:23 PM anmd 10:19 PM EDT) –

– Severe thunderstorms likely from the Middle Mississippi Valley to the Mid-Atlantic through Friday morning

– Excessive rainfall with isolated flash flooding possible over parts of the Northeast through Friday morning

– Widespread Heat Advisories and Excessive Heat Watches/Warnings are in effect for much of the central US and Pacific Northwest

– Potentially heavy rainfall fueled by monsoonal moisture could produce scattered flash flooding in the Southwest and Central Great Basin for the first half of the weekend

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

356 PM EDT Thu Jul 29 2021

Valid 00Z Fri Jul 30 2021 – 00Z Sun Aug 01 2021

…Severe thunderstorms likely from the Middle Mississippi Valley to the Mid-Atlantic through Friday morning…

…Excessive rainfall with isolated flash flooding possible over parts of the Northeast through Friday morning…

…Potentially heavy rainfall fueled by monsoonal moisture could produce scattered flash flooding in the Southwest and Central Great Basin for the first half of the weekend…

…Widespread Heat Advisories and Excessive Heat Watches/Warnings are in effect for much of the central US and Pacific Northwest…

A low pressure wave positioned over the Lower Great Lakes with a cold front trailing southwest through the Ohio Valley to the Central High Plains and a warm front pushing ahead over the Mid-Atlantic and Northeast will be the focus for much of the activity affecting the eastern half of the CONUS during the short-range period. An unstable, moist airmass within the warm sector is expected to interact with upper-level shortwave energy and forcing at the surface via the cold front to generate scattered thunderstorms as well as multicell clusters. Due to the potential for these storms to become severe and produce damaging gusts and possibly a tornado or two, the Storm Prediction Center has issued a Slight Risk for severe thunderstorms for the Ohio Valley, Central Appalachians, and Mid-Atlantic through Friday morning.

Because southeastern Pennsylvania, southern New Jersey, northern Delaware, and northeastern Maryland have the greatest likelihood of experiencing these conditions, an Enhanced Risk of severe thunderstorms has been issued for these areas. Taking into consideration the potential for localized flash flooding in the Northeast due to antecedent saturated soils and expected rainfall totals of 1 to 3 inches with the passage of this system, the Weather Prediction Center has issued a Slight Risk of Excessive Rainfall for the region through tomorrow morning.

Overnight tonight the western tail end of the cold front is expected to become stationary over the Central High Plains and combine with a low pressure wave that slowly drifts from southern to northern Colorado. As the wave becomes embedded within the front it is expected to lift further north into Nebraska with a warm front extending out to the east across the state. This warm front will serve as the focus for convective development on Friday as it interacts with a moist and unstable boundary layer. As afternoon vertical wind profiles become more favorable a cluster of severe thunderstorms will likely develop. Seeing as these storms could generate large hail and gusty winds, the Storm Prediction Center has issued a Slight Risk of severe thunderstorms for parts of eastern Nebraska from Friday morning until Saturday morning. Localized flash flooding will be possible Friday through Saturday along a northwest-southeast axis from southern South Dakota to Tennessee due to the potential for these storms to produce rainfall totals of 1 to 2+ inches in 24 hours. Southeastern Missouri will be at greatest risk for flash flooding on Saturday, therefore, the Weather Prediction Center has issued a Slight Risk of Excessive Rainfall for the area beginning Saturday morning.

Shifting focus to the Southwest, Great Basin and Central/Southern Rockies, showers and thunderstorms are expected to continue throughout the period as the pressure pattern aloft aids the transport of monsoonal moisture into the aforementioned regions. Anomalously high precipitable water values are expected to combine with upper-level energy as well as surface instability due to diurnal heating to produce heavy rainfall on top of already moist soils. Given the potential for high rain rates, antecedent wet conditions, and scattered burn scars throughout the affected areas, the Weather Prediction Center has issued a Slight Risk of Excessive rainfall for parts of the Southwest through Friday morning due to the possible occurrence of localized flash flooding.

On Friday, the flash flooding concern is expected to spread north into the the Central Great Basin and Central Rockies, prompting the issuance of Slight Risk areas in those regions for Friday along with the Southwest.

By Saturday the flash flooding risk is expected to shift even further north into the Northern Great Basin while simultaneously abating in the Southwest. As such, for Saturday a Slight Risk for Excessive Rainfall has been issued for the southern Oregon/Idaho border and parts of the Central Rockies.

Widespread Heat Advisories are currently in effect from the Central Plains/Ohio Valley to the Lower Mississippi Valley/Southeast as hot afternoon temperatures and high humidity are expected to mix to generate heat index values between 100 and 110 degrees, with isolated higher values possible. Excessive heat warnings are also in effect for parts of Kansas, Missouri, Oklahoma, and Mississippi. Throughout northern California and the Pacific Northwest Excessive Heat Watches and Warnings as well as Heat Advisories are also in effect for areas where temperatures on Friday are forecast to be 10+ degrees above average, with highs reaching the upper 90s and low 100s. The main concern with these hot temperatures and/or high heat index values is the onset of heat related illness if the proper precautions aren’t taken. Residents within the previously mentioned regions are urged to drink plenty of fluids, stay in air conditioned rooms, stay out of the sun, and reschedule strenuous activities to the early morning or evening to safeguard their health.

Elsewhere, tropical moisture being pumped into the Gulf Coast states and Florida will help fuel the development of daily showers and thunderstorms through Saturday. Anomalously high precipitable water values over Florida could allow rain rates within these storms to reach 1.5 – 2 inches per hour, which may lead to isolated flooding, primarily in urban areas, through Friday morning. Lastly, Air Quality Alerts are currently in effect for portions of Idaho, Montana, Wyoming, Colorado, Minnesota, and Iowa due to smoke from ongoing wildfires out west and in Canada being advected into their areas by the prevailing northerly-northwesterly winds.

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 Sunday August 01 2021 – Thursday August 05 2021

Hazards:

– Heavy rain across portions of the Northern Rockies, northern Great Basin, Central Rockies, Central and Southern High Plains, Southern Plains, Mid-South, and the interior Northeast, Sun, Aug 1.

– Heavy rain across portions of the Southeast and southern Mid-Atlantic, Sun-Thu, Aug 1-Aug 5.

– Heavy rain across portions of the the Southern Appalachians, Southeast, Tennessee Valley, Lower Mississippi Valley, and the Southern Plains, Mon-Tue, Aug 2-Aug 3.

– Heavy rain across portions of the Southeast, Mon-Thu, Aug 2-Aug 5.

– Excessive heat across portions of the Southern Plains and Lower Mississippi Valley, Sun, Aug 1.

– Heavy rain across portions of western mainland Alaska, Sun, Aug 1.

Detailed Summary:

Multiple threats for heavy rain, specifically across the South, highlight the hazards outlook for the medium-range forecast period (Sunday, August 1 – Thursday, August 5). The period will feature an upper-level ridge over the central/western U.S. and a trough over the Midwest and Northeast that will begin to dig into the central/southern U.S, with a closed low expected to form. A low pressure center will be located over the eastern Great Lakes region, with a warm front extending into New York and a cold front extending west across the Midwest, Plains, and along the Rockies. Additionally, a quasi-stationary boundary will be draped across the Carolinas west through the Southern Plains. As the low pressure center over the eastern Great Lakes moves eastward, increased moisture advecting northward with the warm front into the interior Northeast will lead to the threat of showers and thunderstorms producing 1-2 inches of heavy rain on Sunday (August 1).

There is a significant signal for widespread heavy rain across the South as showers and thunderstorms form along and ahead of the quasi-stationary front and the cold front moving southward, with additional reinforcement from the closed upper-level low. Daily rainfall totals between 1-2 inches and locally higher appear likely. The quasi-stationary front in place across the eastern Carolinas along with the cold front moving in from the north will trigger showers and thunderstorms beginning Sunday.

The quasi-stationary front will begin to move to the southeast towards the Florida Panhandle as the cold front continues to push further south on Monday (August 2), expanding the coverage of showers and thunderstorms deeper into the Southeast. The cold front will become stationary across the Carolinas and Georgia, leading to multiple days of heavy rain that look to continue through the end of the forecast period on Thursday (August 5).

To the west, the cold front looks to move southward farther and faster, with showers and thunderstorms likely developing along the quasi-stationary front and ahead of the cold front across the Southern Plains through the Mid-South and Tennessee Valley on Sunday, and then across the Lower Mississippi Valley and Gulf Coast on Monday into Tuesday (August 3). The cold front is forecast to become quasi-stationary here as well, but the threat for heavy rain looks to shift just offshore into the Gulf. The threat for heavy rain may continue into Wednesday and Thursday along the Gulf Coast if the front does not progress as far south as currently forecast.

Showers and storms associated with an active and expanding Monsoon, as well as an influx of moisture from the Gulf moving northward across the High Plains, will bring the threat of heavy rain to the Rockies and High Plains. Showers and thunderstorms producing 1-3 inches of heavy rain are expected to continue on Sunday across portions of the Front Range of the Rockies as well as the Central and Southern High Plains. Additionally, an anomalously high increase in moisture farther north into central/southern Idaho and eastern Oregon will lead to the threat of 1-2 inches of heavy rain on Sunday. It is worth noting that while the location and intensity of any additional heavy rain threats may not be consistent or widespread enough for outlook areas, model guidance indicates the potential for at least isolated instances of heavy rain elsewhere throughout the region as the Monsoon continues.

Also, on Wednesday (August 4), a shortwave will round the base of the trough ahead of the western portion of the stationary front in New Mexico and Texas. The continued influx of moisture from the Gulf ahead of the front may lead to the chance for heavy rain with showers and thunderstorms developing across southeast New Mexico and west Texas. However, have opted to wait to introduce an outlook area for today until there is more consistency in the model guidance for heavier rain totals.

In addition to the threat for heavy rain, excessive heat will also be a concern across the South before the cold front passes through and storms increase. A combination of high temperatures in the upper 90s to 100 degrees along with dewpoints in the 70s will lead to widespread heat indices between 105 to 110 across portions of the Southern Plains and Mid-South on Sunday. There will be little relief overnight as lows dip only into the upper 70s. This excessive heat is likely further east into the Carolinas as well. However, given the multiple heavy rain outlook areas already noted, opted not to include an outlook area for excessive heat to keep the focus on the heavy rain threat, although an outlook area is warranted.

In Alaska, a low pressure system moving northeast across the Arctic Ocean with a trailing stationary front draped over the western mainland will bring continued chances for heavy rainfall over both the southern Seward Peninsula and portions of the southwest mainland as well as portions of the western Brooks Range on Sunday. Heavy rain may also effect additional areas outside of the noted outlook areas, but these outlook areas were chosen to highlight the locations where model guidance showed the most agreement for significant rainfall. Another storm system will move east across the Bering Sea with a warm front and cold front extending to the southeast over the eastern Aleutians and western Alaskan Peninsula on Tuesday and Wednesday. Showers triggered by these fronts may produce some heavier rain totals between 1-3 inches. However, the heavy rain threat looks to remain isolated and an outlook area will not be introduced for now.

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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