Written by Sig Silber
HEADLINES (Updated 4:21 PM and 6:13 PM EDT) –
– Severe thunderstorms likely from the Upper Midwest to the Mid-Atlantic through Friday morning
– Excessive rainfall with isolated flash flooding possible over parts of the Upper Midwest through Thursday morning
– Potentially heavy rainfall fueled by monsoonal moisture could produce scattered flash flooding in the Southwest through Friday
– Widespread Heat Advisories and Excessive Heat Warnings are in effect throughout the central US
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
401 PM EDT Wed Jul 28 2021
Valid 00Z Thu Jul 29 2021 – 00Z Sat Jul 31 2021
…Severe thunderstorms likely from the Upper Midwest to the Mid-Atlantic through Friday morning…
…Excessive rainfall with isolated flash flooding possible over parts of the Upper Midwest through Thursday morning…
…Potentially heavy rainfall fueled by monsoonal moisture could produce scattered flash flooding in the Southwest through Friday…
…Widespread Heat Advisories and Excessive Heat Warnings are in effect throughout the central US…
A long, slow moving frontal boundary extending from the Central High Plains through the Upper Midwest to the Mid-Atlantic will be the focus for much of the activity over the CONUS during the short-range period. A low pressure wave set up over the Upper Midwest is expected to interact with upper-level shortwave energy and surface instability to produce both heavy rain and thunderstorms over the region. Taking into consideration the antecedent saturated soils and the potential for rainfall accumulations up to and exceeding 2″ in 24 hours, which could lead to localized flash flooding, the Weather Prediction Center has issued a Slight Risk of Excessive Rainfall for portions of Wisconsin and Michigan through Thursday morning.
As afternoon vertical wind profiles become more favorable, severe thunderstorms and supercells will likely develop throughout the Upper Midwest that hold the potential to produce damaging winds, large hail, and a few tornadoes. Much of Wisconsin and the surrounding areas have the greatest likelihood of experiencing these conditions, therefore, the Storm Prediction Center has issued a Moderate Risk of severe thunderstorms for portions of Wisconsin through Thursday morning.
The low pressure wave and its associated frontal boundary are forecast to move from the Great Lakes area overnight and into the Ohio Valley/Mid-Atlantic by Thursday morning. Though rainfall totals are expected to be a bit lower than the previous day’s, saturated soils throughout the regions due to 150-400% above normal precipitation will still make isolated flash flooding a concern.
Additionally, a moist, unstable airmass extending from the Ohio Valley to the Mid-Atlantic is expected to interact with the advancing cold front to produce linear thunderstorm clusters and supercells. Due to the potential for these storms to produce damaging gusts and possibly a tornado or two, the Storm Prediction Center has issued a Slight Risk of severe thunderstorms for the Ohio Valley, Central Appalachians, and Mid-Atlantic from Thursday through Friday morning.
Shifting focus to the Southwest and Central Great Basin, showers and thunderstorms are expected to continue throughout the period as high pressure aloft aids the transport of monsoonal moisture into the region. Anomalously high precipitable water values are expected to combine with surface instability due to diurnal heating to produce hourly rain rates between 0.5 and 1 inches, with isolated higher amounts possible. Given these high rain rates, antecedent wet conditions, and scattered burn scars throughout the regions, the Weather Prediction Center has issued a Slight Risk of Excessive Rainfall for portions of Arizona, Nevada, Utah, and Colorado from Thursday through Friday due to the potential for localized flash flooding to occur.
Widespread Heat Advisories are currently in effect from the Northern Plains/Upper Midwest to the Lower Mississippi Valley/Southeast as hot afternoon temperatures mix with high humidity to generate heat index values between 100 and 110 degrees, with isolated higher values possible. The main concern with heat index values this high is the onset of heat related illness if the proper precautions aren’t taken. Residents of these 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.
Excessive Heat Warnings are also in effect for portions of Minnesota, Kansas, Missouri, Oklahoma, and Mississippi. In Northern California and the Pacific Northwest, Excessive Heat Watches and Warnings as well as Heat Advisories are in effect for areas where temperatures on Friday are expected to be above average, with highs reaching the high 90s and low 100s.
The Storm Prediction Center has issued an Elevated Risk of Fire Weather for portions of the Northern Plains through Thursday morning due to prevalent dry fuels throughout the region, low relative humidity values, and winds between 15 and 20 mph. Air Quality Alerts are in effect for portions of Washington, Idaho, Montana, Wyoming, and Colorado due to wildfire smoke from ongoing wildfires.
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 Saturday July 31 2021 – Wednesday August 04 2021
Hazards:
– Heavy rain across portions of the Lower Missouri Valley and Middle Mississippi Valley, Sat, Jul
31.– Heavy rain across portions of the Front Range and Central and Southern High Plains, Sat-Sun, Jul 31-Aug 1.
– Heavy rain across portions of the Northern Rockies, Sat-Sun, Jul 31-Aug 1.
– Heavy rain across portions of the interior Northeast, Sun, Aug 1.
– Heavy rain across portions of the Southern Plains, Mid-South, and Tennessee Valley, Sun, Aug 1.
– Heavy rain across portions of the Western and Central Gulf Coast, Lower Mississippi Valley, and the Southeast, Mon-Tue, Aug 2-Aug 3.
– Heavy rain across portions of the Southeast, Sun-Wed, Aug 1-Aug 4.
– Excessive heat across portions of the interior Pacific Northwest, Sat, Jul 31.
– Excessive heat across portions of the Southern Plains and Mid-South, Sat-Sun, Jul 31-Aug 1.
– Heavy rain across portions of mainland Alaska, Sat-Sun, Jul 31-Aug 1.
Detailed Summary:
Multiple threats for heavy rain across the CONUS and Alaska highlight the hazards outlook for the medium-range forecast period (Saturday, July 31 – Wednesday, August 4). The start of 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 significantly into the Southern U.S. A low pressure center over Canada will move to the east, with a trailing cold front moving to the southeast across the Plains and Midwest and into the Southeast along the northwesterly upper-level flow as the trough digs into the South.
A second, quasi-stationary front will be draped from the Carolinas west into the Missouri Valley. Organized thunderstorms are expected to develop on Saturday (July 31) along the quasi-stationary front and any mesoscale boundaries produced from overnight convection across the Lower Missouri Valley and Middle Mississippi Valley. Heavy rain of 1 to 2 inches is forecast, with locally higher amounts of 3 inches and above possible.
As the low pressure center over Canada moves eastward, a secondary low is forecast to develop over the eastern Great Lakes with a warm front extending to the southeast, moving to the northeast across the interior Northeast on Sunday (August 1). Increased moisture advecting northeast with the warm front will lead to the threat of showers and thunderstorms producing 1-2 inches of heavy rain across the area.
Later in the period, 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, with additional reinforcement from the cold front moving in from the northwest and a closed low developing at the base of the upper-level trough. Daily rainfall totals between 1-2 inches and locally higher appear likely, particularly over the Carolinas. A weak low pressure center over the Carolinas along with the quasi-stationary front already in place will lead to showers and thunderstorms beginning Sunday (August 1). The cold front from the northwest will begin to move across the region, with the quasi-stationary boundary beginning to move further to the southeast towards the Florida Panhandle.
The cold front will become quasi-stationary across the Southeast by Tuesday, continuing shower and thunderstorm chances through at least Wednesday (August 4). Further west, the cold front looks to move southward a bit faster, with showers and thunderstorms possible across the Southern Plains through the Mid-South and Tennessee Valley on Sunday and across the Lower Mississippi Valley and Gulf Coast on Monday (August 2) and Tuesday (August 3). The cold front is forecast to become quasi-stationary here as well, and if the front does not progress as far south as currently forecast the threat for heavy rain may continue into Wednesday along the Gulf Coast.
Precipitation 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 around 1-2 inches of heavy rain are expected both Saturday and Sunday across portions of the Front Range of the Rockies as well as the Central and Southern High Plains. The cold front pushing in from the northeast may help to enhance this rainfall on Sunday. Showers and storms will continue into Monday as this front stalls along the High Plains, but an extension of the outlook area was not included for now given the lighter nature of the forecast rainfall in the current model guidance. Additionally, an anomalously high increase in moisture further north into central and southern Idaho will lead to the threat of heavy rain on both Saturday and 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.
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 precipitation increases. A combination of high temperatures in the upper 90s to low 100s along with dewpoints in the 70s will lead to widespread heat indices between 105 to 110, locally as high as 115, across portions of the Southern Plains and Mid-South Saturday and Sunday. There will be little relief overnight as lows dip only into the upper 70s to low 80s. This excessive heat is likely further east across the Southeast to southern South Carolina 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. Excessive heat is also a concern for the interior Pacific Northwest at the beginning of the period, with highs in low to mid-100s continuing through Saturday for northeastern Oregon, eastern Washington, and northwestern Idaho.
In Alaska, a low pressure system moving northeast across the Arctic Ocean with a trailing cold front moving onshore over the western mainland will bring continued chances for significant heavy rainfall over both the southern Seward Peninsula and portions of the southwest mainland as well as portions of the western Brooks Range on Saturday. This will continue into Sunday as the front becomes stationary. Some of the heaviest rainfall may approach climatological extremes for these areas. 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.
(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.
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
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 |