Written by Sig Silber
HEADLINES (Updated 5:26 PM EDT) –
– Showers, thunderstorms, and the potential for flooding across the central and eastern U.S.
– Additional rounds of heavy rain and thunderstorms found throughout the Southwest
– Excessive heat builds into the Northern Plains and Intermountain West this 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
406 PM EDT Fri Jul 16 2021
Valid 00Z Sat Jul 17 2021 – 00Z Mon Jul 19 2021
…Showers, thunderstorms, and the potential for flooding across the central and eastern U.S….
…Additional rounds of heavy rain and thunderstorms for the Southwest…
…Excessive heat builds into the Northern Plains and Intermountain West this weekend…
A slow moving frontal system will progress east across the central and eastern U.S. through the short-term forecast period. Showers and thunderstorms are expected to continue along and ahead of the front in the presence of a seasonably moist airmass. Widespread rainfall of 1-2 inches is likely over the weekend from the Northeast and Mid-Atlantic southwestward through the Southern Plain. A Slight Risk for Excessive Rainfall remains in effect through tomorrow morning for portions of the Lower Great Lakes and Ohio Valley where locally higher amounts of 3-5 inches of rain are possible. The greatest risk for flooding will be further east on Saturday where a Moderate Risk is now in effect for southern New England, southern New York, northeastern Pennsylvania, and northern New Jersey. A broader Slight Risk is in place for the northern Mid-Atlantic, New York, and southern New England. Locally heavy rainfall amounts of 2-3 inches and higher are possible.
Attention is focused on the Moderate Risk area due to the consistent heavy rainfall seen over the region recently leading to already saturated soils. Some areas have seen rainfall between 300 to 500% above normal in the last week. Heavy rainfall and the potential for flooding will be a concern elsewhere further south and west along the front from the Carolinas west through the Southern Appalachians, Tennessee Valley, Mid-South, and Southern Plains. Broad Marginal Risks for excessive rainfall are in effect for these areas on both Saturday and Sunday.
In the Southwest, daily showers and thunderstorms sparked by the continued influx of Monsoonal moisture will lead to the potential for flooding. Marginal Risks for excessive rainfall are in effect for both Saturday and Sunday across portions of the Desert Southwest and Southern Rockies. Heavy downpours look to remain somewhat isolated, but slow moving storms with instances of 1-2 inches of rain may pose a risk for flash flooding, especially over any burn scars or in more urban areas.
Besides the heavy rainfall, a heatwave across the Northern Tier of the country will become an increasing concern into the weekend as a ridge builds in over the West. High temperatures will begin to peak first and foremost in eastern Montana, where an Excessive Heat Warning will take effect Saturday afternoon. Highs in the low 100s Saturday may approach the mid 100s on Sunday. The heat will continue to expand on Sunday to include the northern Intermountain West, Plains, and Midwest. Highs in the low 100s are forecast for Idaho, northern Utah, and northern Nevada, with highs in the mid to upper 90s expected elsewhere across the region. An Excessive Heat Watch is in effect for the eastern Snake River Valley in Idaho.
Elsewhere, thunderstorm chances will increase on Saturday and Sunday across the Central and High Plains as the western end of the front remains stationary to the east of the Front Range of the Rockies and a shortwave moves southward across the region. Some instances of heavy rain with rates of up to 1.5 inches per hour are possible on Sunday, and a Marginal Risk is in effect for portions of the Central Plains.
The cold front moving across the East and associated showers and storms will bring a cool down to the Mid-Atlantic and Northeast, with high temperatures dropping into the 70s for New England and the 80s further South by Sunday. Below normal temperatures for mid-July are also expected behind the front across most of the eastern U.S. and Plains.
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 July 18 2021 – Thursday July 22 2021
Hazards:
– Heavy rain across portions of the central Plains to the lower Mississippi Valley, as well as portions of the Mid-Atlantic, Sun-Mon, Jul 18-Jul 19.
– Heavy rain across portions of the southwestern Texas, Tue-Thu, Jul 20-Jul 22.
– Heavy rain across portions of the Mogollon Rim to the Gila Mountains in Arizona, Sun-Thu, Jul 18-Jul 22.
– Flooding possible across portions of the mid-Mississippi Valley, the Great Lakes, and the Ohio Valley.
– Flooding occurring or imminent across portions of Florida and the mid-Mississippi Valley.
– Excessive heat across portions of the Snake River valley and northern Rockies, Sun-Mon, Jul 18-Jul 19.
– Excessive heat across portions of the northern High Plains, Sun-Tue, Jul 18-Jul 20.
– Much above normal temperatures across portions of the central and northern Great Basin, the northern to central Rockies, across the northern Plains, and into the upper Midwest, Sun-Thu, Jul 18-Jul 22.
– Much above normal temperatures across portions of the central Rockies, northern Plains, and into the upper Midwest, Wed-Thu, Jul 21-Jul 22.
– Heavy rain across portions of northwestern Alaska, Tue-Wed, Jul 20-Jul 21.
Detailed Summary:
During the medium range forecast period (Sunday, July 18th to Wednesday, July 22nd), an upper-level trough settling across the Great Lakes and the Northeast will extend a cold front southwestward into the central Plains. The front is forecast to gradually push through the central U.S., then into the East Coast and across the Deep South by the middle of next week. Model guidance continues to indicate the likelihood of moderate rainfall ahead of this slowly advancing front but with a fair amount of uncertainty regarding if and where low pressure waves will form and develop along the front.
The development of these frontal waves will be important in determining if and where heavier rainfall and thunderstorms will be triggered. The highest chance for marginally heavy rain appears to be across portions of the Mid-Atlantic as well as from the central Plains to the lower Mississippi Valley on Sunday and Monday. Other areas of heavy rainfall are possible especially near where low pressure waves form near the front. By Tuesday and into midweek, models are indicating a good chance of heavy rain lingering across southwestern Texas as the front stalls across the area.
Over the southern Rockies into the Desert Southwest, monsoonal moisture will keep a good chance of showers and afternoon/early evening thunderstorms through the medium-range period. Most areas should see rainfall below hazard levels but the upslope portion of the Mogollon Rim to the Gila Mountains in Arizona appears to be under the highest threat of heavy rain through the middle of next week when models indicate an increasing influx of the moisture from the south.
Meanwhile, the heatwave is expected to continue from the central and northern Great Basin eastward across the northern Plains and into the upper Midwest under a persistent upper ridge through much of the medium range period. The highest temperature anomalies are expected over the northern High Plains, where high temperatures into the triple digits are forecast through midweek next week. Excessive heat is thus indicated for this area. Excessive heat is also indicted along the Snake River valley and parts of the northern Rockies Sunday and Monday when the heat is forecast to be most intense. In addition, much of the Dakotas, northeast Wyoming, and the western half of Minnesota are experiencing severe to exceptional drought that will likely worsen due to the persistent heat and lack of rain.
Alaska will likely enter an extended period of wet weather toward the middle of next week as a series of occluded cyclones is forecast to steadily move across the Bering Sea toward Mainland. Latest model guidance has generally backed off regarding the predicted rainfall amounts across western Alaska with the associated upper trough sliding farther southeast to develop a low over the Gulf of Alaska. Only a small area of heavy rain is indicated over portions of northwestern Alaska Tuesday to Wednesday ahead of the arrival of the first cyclone. However, widespread moderate rainfall can be expected to make steady progress across much of Alaska through the middle of next 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.
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 |