Written by Sig Silber
HEADLINES Updated 4:21 PM and 4:51 PM EDT) –
– The potential for flash flooding and severe weather continues across portions of the Northern Plains and Midwest
– Heavy rain and flooding possible for the Mid-Atlantic Friday
– Uncomfortable and potentially dangerous heat continues throughout much of the central and eastern United States, as well as the Desert Southwest
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.
Readers can scan through this article or jump to where they want to go via the links to the right. To get back to the Directory, hit the back arrow at the top of the URL bar on your screen. But in many cases, one of my Editors has graciously inserted a Return to Directory link to click so that is even easier. This is so high tech that I hardly believe it. |
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CONUS Focal Points
Short Range Focal Points
Short Range Forecast Discussion NWS Weather Prediction Center College Park MD
400 PM EDT Thu Aug 26 2021
Valid 00Z Fri Aug 27 2021 – 00Z Sun Aug 29 2021
…The potential for flash flooding and severe weather continues across portions of the Northern Plains and Midwest…
…Heavy rain and flooding possible for the Mid-Atlantic Friday…
…Uncomfortable and potentially dangerous heat continues throughout much of the central and eastern United States, as well as the Desert Southwest…
A persistent frontal system as well as a shortwave trough moving across the Northern Tier of the U.S. will continue to lead to the chance of heavy rain, flooding, and severe weather across portions of the Northern Plains and Midwest. A quasi-stationary front draped from the Lower Great Lakes westward through Nebraska should begin to lift slowly northward as a warm front throughout the day Friday. Widespread showers and thunderstorms expected overnight tonight along the boundary and will continue on Friday. There is a Slight Risk (level 2 of 4) for excessive rainfall Friday for portions of southeastern Minnesota and central Wisconsin as another 2 to 4 inches of rain are expected on top of heavy rain that is already falling across the region today.
Additionally, the Storm Prediction Center has issued a Slight Risk (level 2 of 5) for severe weather for northern Iowa, southeastern Minnesota, and central Wisconsin as isolation south of the boundary will help support more robust thunderstorms with the threat of large hail and high winds. The shortwave approaching from the west on Friday will also help to begin to push the frontal system eastward across the Northern High Plains, and thunderstorms are expected to develop along and ahead of the front.
The Storm Prediction Center has issued a Slight Risk of severe weather for portions of southeastern Montana and the western Dakotas mainly for the threat of large hail. As the shortwave and frontal system continue east, thunderstorms are expected to develop again on Saturday with another Slight Risk highlighted by the Storm Prediction Center for portions of southern Minnesota into northwestern Wisconsin.
Further east, a cold front will push southward through the Northeast on Friday and begin to stall across the Mid-Atlantic Friday evening. There is a Slight Risk of excessive rainfall for Friday from eastern Pennsylvania and northern Maryland east into central and northern New Jersey. Showers and storms along the boundary may produce a couple inches of rain over a region with recently saturated soils due to heavy rain from Henri. Showers and storms will continue on Saturday as the front remains quasi-stationary.
Heat will also be a major story throughout the forecast period. Ahead of the fronts, highs in the mid- to upper 90s are forecast from the Mid-Atlantic and Carolinas west through the Ohio Valley, Mississippi Valley, and into the Central Plains on both Friday and Saturday. High humidity will lead to heat indices closer to 100.
Temperatures will also rise into the 90s over the Great Lakes region on Saturday. There will be little relief from the heat at night, as lows are expected to remain well above normal and only fall into the low to mid-70s.
In the Desert Southwest, highs in the 110s are expected on Friday, and an Excessive Heat Warning remains in effect for the area through Friday evening. The high temperatures will cool a little on Saturday but still generally be in the upper 100s to lower 110s.
Elsewhere, showers and storms are likely along the Gulf Coast as moisture increases ahead of T.D. Nine, which is forecast by the National Hurricane Center to move northwestward into the Gulf of Mexico. Some Monsoonal showers and storms are also possible across Arizona and New Mexico on Saturday.
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
The below does not update and is a still rather than the 40-hour animation of the recent past. But if you click on it you will get the upadated animattion. If it does not upload completely you need to hit the refresh button.
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Day 3 – 7 Hazards
Valid Sunday August 29 2021 – Thursday September 02 2021
Hazards:
– Heavy rain across portions of the Southeast, the Middle Mississippi Valley, the Lower Mississippi Valley, the Southern Plains, and the Tennessee Valley, Sun-Mon, Aug 29-Aug 30.
– Heavy rain across portions of the Central Plains, the Middle Mississippi Valley, the Upper Mississippi Valley, and the Northern Plains, Mon, Aug 30.
– Heavy rain across portions of the Lower Mississippi Valley, the Central Appalachians, the Tennessee Valley, the Middle Mississippi Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, and the Ohio Valley, Tue-Wed, Aug 31-Sep 1.
– Heavy rain across portions of the Southwest, Wed-Thu, Sep 1-Sep 2.
– Flooding possible across portions of the Great Lakes and the Upper Mississippi Valley.
– High winds across portions of the Southeast, the Lower Mississippi Valley, and the Southern Plains, Sun-Mon, Aug 29-Aug 30.
– High significant wave heights for coastal portions of the Southeast, the Lower Mississippi Valley, and the Southern Plains, Sun, Aug 29.
– Heavy rain across portions of mainland Alaska, Thu, Sep 2.
Detailed Summary:
The track and resulting hazards generated by Tropical Depression Nine is the headliner through at least the first half of the medium range period (Sunday, Aug 29 – Thurs, Sept 2). Tropical Depression Nine is forecast to organize and strengthen over the next 24 hours and make landfall in northwest Cuba late Friday. It will enter the Gulf of Mexico tracking northwest while encountering light levels of vertical wind shear and passing over the very warm waters. The stage is set for T.D. Nine to rapidly intensify, perhaps all the way up until landfall, along the central Gulf Coast. Latest ensemble guidance has become more clustered over the central Louisiana coast, but some members are as far west as the Upper Texas coast or as far east as Mobile Bay. There is still some uncertainty regarding exact landfall, which not only varies by location but also timing. Some guidance suggests landfall could be Sunday afternoon or some time Monday night. Regardless, the expectation is for a dangerous hurricane to take aim at the Louisiana coast bringing life threatening hazards to parts of the central Gulf Coast and into the Lower Mississippi Valley.
Hazards will vary depending upon intensity and track with areas just north and east of the storm most at risk for greater impacts. Life threatening storm surge and inland flooding is possible ahead of and just east of the storm’s expected track. Rainfall totals exceeding 12 inches are anticipated somewhere along the central or eastern Louisiana coast with torrential rainfall rates potentially leading to dangerous flash flooding into south-central Louisiana. Destructive hurricane force winds will be focused along the coast and a little further inland, or so long as the storm can maintain hurricane status.
As the storm pushes further inland, so will its tropical storm force wind field where a swath of wind damage is likely to include (but is not limited to) downed trees, power lines, and structural damages to homes and businesses. Also, northeast of the storm’s track will likely contain a severe weather threat as tornadoes may develop across parts of the Deep South late Sunday into Monday.
Eventually, the flood threat becomes the primary hazard of note by Tuesday and Wednesday as T.D. Nine’s remnant tropical moisture becomes focused along a frontal boundary inching south through the Tennessee Valley, southern and central Appalachians, and Mid-Atlantic. Specific locations in these regions have received heavy rainfall and dealt with areas of flash flooding in recent weeks, so rainfall on the order of 2-5 inches could promote additional flash flooding concerns in these areas. Please visit the NHC website for the latest track and intensity forecast information in the days to come and follow the advice of local officials for those in the path of T.D. Nine.
There is another tropical system that could also leave its mark on the U.S., more specifically in the Southwest. Tropical Storm Nora is forecast to strike the Baja California peninsula and weaken as it tracks north. Its remnant moisture is expected to be transported north ahead of an upper trough diving into the Pacific Northwest. Latest 12Z Euro ENS mean has PWATs nearly 2 STDs above normal out to days 5-6 in the Four Corners region. Guidance remains unclear as to when the heaviest rounds of showers and thunderstorms pass through Arizona and into the heart of the Four Corners region, but ample moisture courtesy of Nora could lead to areas of heavy rainfall and flash flooding in parts of the region next week.
Also, another round of heavy rainfall within a cluster of thunderstorms is possible in parts of the North Central U.S. late Monday into early Tuesday just north of a warm front forecast to track into the region. Localized flash flooding is possible in the highlighted area of the Midwest.
Over Alaska, the start of September looks stormy as another occluded storm system is expected to impact the state, this time generating moderate to heavy rainfall over the Aleutians, east towards the upper Peninsula, and along the west-central Gulf coast. Roughly 2 to 3 inches of drenching rain is possible for the southern coastal portion of the upper Peninsula, Kodiak Island, the Kenai Peninsula, and areas surrounding the Cook Inlet. There may also be some gusty winds It is possible for heavy rainfall to extend farther east along the eastern half of the Gulf coast and potentially towards the northern Panhandle by day 7, but confidence in totals and timing is low at this time. Temperature-wise, a more autumn-like start to the period on Sunday gradually warms up into next week to more seasonal levels by mid-week.
(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 snow coverage in the Fall
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Drought Coverage
We include drought information in this section.
More information can be found here.
August Drought Outlook.
Seasonal Outlook Issued August 19, 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
For those interested in more detail, there are additional weather maps and information in the MORE WEATHER Addendum. The link to the Addendum is here. |
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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
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. |
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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 | |
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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 |