Written by Sig Silber
HEADLINES (Updated 3:56 PM and 5:05 PM EDT) –
– Heavy rain and scattered flash flooding possible tonight across southeastern New England, the southern Rockies, and the Florida Big Bend region
– Dangerous heat found across the Desert Southwest and Interior Pacific Northwest through Thursday
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
311 PM EDT Wed Aug 04 2021
Valid 00Z Thu Aug 05 2021 – 00Z Sat Aug 07 2021
…Heavy rain and scattered flash flooding possible tonight across southeastern New England, the southern Rockies, and the Florida Big Bend region… …
Dangerous heat found across the Desert Southwest and Interior Pacific Northwest through Thursday…
A mid- to upper-level ridge building from the Southwest into the Pacific Northwest will continue to spread drier conditions across interior sections of the West Coast while shifting most of the monsoonal showers farther eastward from the central and southern Rockies into the High Plains. Locally heavy rain is possible this evening over the southern Rockies/High Plains before diminishing by Thursday. Scattered flash flooding will be a particular concern near burn scars.
Meanwhile, the drying trend brought by the building ridge will lead to above average temperatures across the Desert Southwest northward to the interior Pacific Northwest. High temperatures in the 110s will be common in the Desert Southwest for the next couple of days while upper 90s to 100 degrees are forecast for the interior Pacific Northwest this afternoon. As a result, Excessive Heat Warnings are in effect for the Desert Southwest through Thursday evening while Heat Advisories are in effect for this afternoon across the interior Pacific Northwest. In addition, fire weather danger is forecast to increase over the Great Basin into Thursday.
A system moving east from the Pacific will begin to bring cooler air into the Pacific Northwest on Thursday together with a round of rain/thunderstorms eastward into the northern Rockies. The rain/storms are expected to continue across the northern Rockies into early Friday as the heat spreads further east into the northern/central Plains and upper Midwest, where widespread high temperatures are forecast to reach into the upper-80s and 90s by Friday.
Elsewhere, a frontal boundary is forecast to remain nearly stationary near the Gulf Coast as well as along and just off the East Coast through the end of the week. An axis of heavy rain is forecast to extend along the boundary and associated waves of low pressure. The heaviest rainfall should stay just off the coast; however, a modest influx of moisture is expected to enter southeastern New England tonight and could produce around 1-2 inches of rainfall. Much of this region (besides Cape Cod) has experienced a very wet summer thus far, therefore isolated to scattered flash flooding is possible from eastern Connecticut to coastal Maine. Some heavy rainfall is also possible across northern Florida and the Big Bend region, as well as across southern Texas for the next couple of days.
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 August 07 2021 – Wednesday August 11 2021
Hazards:
– Heavy rain across portions of the Midwest, Sat-Sun, Aug 7-Aug 8.
– Heavy rain across portions of the Southwest, Sat-Mon, Aug 7-Aug 9.
– Flooding possible across portions of the Southeast.
– Excessive heat across portions of the Central/Southern Plains and the Middle and Lower Missouri and Mississippi Valleys, Sun-Tue, Aug 8-Aug 10.
– Excessive heat across portions of the Southern Plains and Lower Mississippi Valley, Sun-Wed, Aug 8-Aug 11.
– Heavy rain across portions of the Alaska Panhandle and Southcentral mainland Alaska, Sun-Tue, Aug 8-Aug 10.
Detailed Summary:
The potential for heavy rain in the Midwest and hot weather in the central part of the country highlight the hazards outlook for the medium range forecast period (Saturday, August 7 – Wednesday, August 11). A shortwave trough will move east across the Northern Plains and Midwest Saturday (August 7) and Sunday (August 8). At the surface, a series of warm fronts will move north across the region, advecting higher moisture northward and further encouraging shower and thunderstorm development. Widespread heavy rain totals of 1 to 2 inches, with locally higher amounts, look likely from Iowa and central/southern Minnesota east across Wisconsin, northern Illinois, and western portions of Michigan. The rain chances are highest further west on Saturday and shift to the east on Sunday.
As this trough departs to the east, heat will return to the Central/Southern Plains as well as the mid- and lower Missouri and Mississippi Valleys beginning on Sunday and last through the end of the period. High temperatures in the mid- to upper 90s combined with dewpoints in the 70s will lead to afternoon heat indices of 105 and higher. Additionally, there will be little relief overnight as temperatures only fall into the mid- to upper 70s. A cold front approaching the region from the north as well as another trough moving across the Northern Tier from the west look to bring cooler temperatures to the northern portion of the outlook area by Wednesday (August 11).
In the southwest, heavy rain is also a concern for southeastern Arizona from Saturday through Monday (August 9) as moisture increases from the south, encouraging the chance for Monsoonal showers. Daily rainfall amounts greater than 0.5 inches appear probable. These showers may continue later into the period and spread further north into Arizona, but there is less consistency across the model guidance for heavier rainfall amounts as the surface moisture does not look to be as high.
Elsewhere, showers and storms look likely to form across the eastern Carolinas along a dying stationary boundary on Saturday. However, rainfall amounts do not look to be particularly hazardous at this time. Additionally, an upper-level ridge will build to the north over the East Coast towards the end of the period. The combination of high temperatures above 90 as well as increasing humidity may lead to afternoon heat indices approaching 100 degrees and overnight lows in the 70s, particularly for southern portions of the Mid-Atlantic. This heat looks to continue beyond the current medium-range forecast period as well. For now, the heat does not look hazardous enough for an outlook area. However, the region will be monitored for a potential outlook area in the future if confidence increases in the potential for more widespread, oppressive, and long-lasting heat.
In Alaska, the chance for significant rainfall of several inches over multiple days has been increasing for southern portions of the mainland and into the Panhandle. A storm system over the Bering Sea will move east across the southern mainland as well as the Gulf of Alaska Sunday morning. Increasing moisture ahead of a warm front moving north towards the coastal Kenai Peninsula, Southcentral, and the northwestern Panhandle will lead to daily showers from Sunday through Tuesday. Rainfall totals over 2 inches are likely with significantly higher amounts possible. Additional showers look likely further south into the Panhandle and may continue later into the period, but the current outlook area was chosen to highlight the region where model guidance is most consistent on the location of significant heavy rainfall. The Alaskan Peninsula may also see some heavy rain as well as high winds Sunday into Monday as the system moves through. However, the rainfall amounts and winds do not appear to be particularly hazardous at this time.
(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 |