Written by Sig Silber
HEADLINES (Updated 4:31 PM EDT) –
– Flash flooding and severe weather potential will spread from the south-central U.S. this evening and tonight into the Southeast on Saturday
– Rain and snow increasing across the West this weekend
– Ongoing fire weather danger is expected for the Four Corners states to the Southern High Plains
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 358 PM EDT Fri Apr 23 2021
Valid 00Z Sat Apr 24 2021 – 00Z Mon Apr 26 2021
…Flash flooding and severe weather potential will spread from the south-central U.S. this evening and tonight into the Southeast on Saturday…
…Rain and snow increasing across the West this weekend…
…Ongoing fire weather danger is expected for the Four Corners states to the Southern High Plains…
A surface low pressure system and its associated fronts are forecast to move from the Southern Plains eastward into the Southeast on Saturday. Moisture flowing in from the Gulf of Mexico combined with these features will continue to produce rain and thunderstorms across those regions. Through tonight, a Moderate Risk of excessive rainfall is in place for central Louisiana and southwestern Mississippi as multiple inches of rain training over that area could lead to numerous flash floods, some of which could be locally significant.
Marginal to Slight Risks of flash flooding as well as Enhanced Risks of severe weather are also in place for portions of the Southern Plains, Lower Mississippi Valley, and the Southeast through tonight. The Southern Plains in particular could see damaging hail of greater than 2″ in diameter with these storms.
Then on Saturday, thunderstorm chances shift to the Southeast. Slight to Enhanced Risks of severe weather are delineated for the Southeast into the Carolinas for tornado, high wind, and hail threats, with flash flooding possible as well. By Saturday night and Sunday, the low pressure system is forecast to deepen over the Atlantic and move northeastward, leading to rain showers across the Mid-Atlantic and Northeast.
Across the western U.S., a couple of rounds of upper-level energy and troughing will push frontal systems into the region and help cause precipitation there, beginning in the Pacific Northwest tonight and expanding south and eastward into the Northern Rockies, Great Basin, and California through the weekend. Precipitation will generally be in the form of snow in higher elevations and rain in lower elevations. The Sierra Nevada is likely to see the heaviest snow through Sunday, with over a foot expected, and Winter Storm Warnings are in place there.
Elsewhere, the north-central U.S. could see light precipitation tonight into Saturday as a front passes through, with light mixed precipitation or snow possible in parts of the Northern Plains, Upper Midwest, and Upper Great Lakes. Rain is likely farther south in the Ohio Valley between the two frontal systems. Then another round of snow could occur across the north-central region again by Sunday with cooler than normal temperatures north of a warm front.
Meanwhile, conditions in the southwestern U.S. look to remain dry over the next couple of days. Dry conditions with low relative humidities and dry ground, as well as enhanced gusty winds from the approaching upper-level troughing, will lead to ongoing fire danger for the Four Corners states into western Texas. A Critical Risk of fire weather is in place today for the Southern High Plains, with Elevated Risks stretching back into the Four Corners today and Saturday. Another round of dangerous fire weather conditions can also be expected early next week.
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 |
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These graphics update and can be clicked on to enlarge. You can see where the weather will be | |
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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 Monday April 26 2021 – Friday April 30 2021
Hazards:
– Heavy rain across portions of the Middle/Lower Mississippi Valley, the Tennessee/Ohio Valley, the Great Lakes, the Mid-Atlantic, the Southern Appalachians, the Southeast, the Southern Plains, and the Ohio Valley, Tue-Thu, Apr 27-Apr 29.
– Severe weather across portions of the Central Plains and the Southern Plains, Tue, Apr 27.
– Flooding occurring or imminent across portions of the Lower Mississippi Valley.
– High winds across portions of the Central Plains, and the Central Rockies, Mon, Apr 26.
– Much above normal temperatures across portions of the Northern/Central Great Basin, California, and the Southwest, Wed-Fri, Apr 28-Apr 30.
– Much above normal temperatures across portions of the Mid-Atlantic, the Northeast, and the Central Appalachians, Tue-Wed, Apr 27-Apr 28.
– Enhanced wildfire risk across portions of the Southern Rockies, the Southern Plains, and the Southwest, Mon, Apr 26.
– Heavy precipitation across portions of the Alaska Panhandle, Wed-Thu, Apr 28-Apr 29.
Detailed Summary:
The main upper-level feature causing impactful weather in the medium range period (Monday, April 26 – Friday, April 30) will be an upper trough/low dropping southward through the Northwest and continuing eastward through the central U.S. through the middle part of the week, while a potent frontal system moves just ahead of the trough. These features will spread precipitation to much of the U.S. along with other hazards. First, precipitation is likely across the Intermountain West. Higher elevation heavy snow is expected in higher terrain. Locally heavy precipitation is also possible across portions of the Northern/Central Rockies. Meanwhile, winds are expected to increase ahead of the trough on Monday, with much of southern Colorado seeing the possibility for high winds. Along with the windy conditions, low relative humidity and dry ground will likely lead to dangerous fire weather conditions for the Southern High Plains on Monday.
As the upper-level trough and front move east, Gulf of Mexico moisture will be steered into the central U.S. and enhance rainfall amounts near and ahead of the front and associated surface lows. Current forecasts show heavy rain progressing eastward from the Southern Plains Tuesday into the Middle/Lower Mississippi Valley as well as the Tennessee/Ohio Valley Wednesday, with some rain spreading into the Southeast and Southern Appalachians on Thursday. Heavy rain amounts could also stretch into the Midwest to Upper Great Lakes region as a surface low and warm front move north, with Wednesday looking to be the most active day, though some rain is also possible (and potentially a bit to the West) on Tuesday. Rain showers will spread into the eastern third of the country by Friday despite there being less signal for heavy amounts to continue into that day. Severe weather is also a possibility given the pattern, and the Storm Prediction Center has outlook-ed the potential for severe weather on Tuesday across the Southern/Central Plains. Some areas across the southern tier will be sensitive to additional rainfall after the heavy rainfall event late this week, as well as rainfall events earlier this month.
Temperatures will generally be cooler than average behind the cold front and upper-level trough, with above normal temperatures ahead of the front and underneath the upper-level ridges in both the east and west coasts. We could reach much above normal temperatures in the Northeast and West mid to late next week as model trends appear to signal at strengthening ridges over those respective sides of the country.
An additional threat early next week will be a fairly deep surface low moving as a nor’easter and impacting the northeastern U.S. Sunday into Monday. The tight pressure gradient could cause a period of gusty winds along coastal New England on Sunday, and as the low tracks into southeastern Canada Monday, enhanced winds are possible especially across higher terrain areas of northern New England. Precipitation in the form of rain is likely at least for eastern portions of Maine as well.
Then toward midweek next week, chances for precipitation increase in the Northwest. Details regarding the timing and amounts of this precipitation remain in question at this point, so while it is possible that some areas especially in the Cascades could see heavy amounts, no area is depicted at this time.
Over Alaska, the anomalously warm temperatures being experienced especially into the North Slope in the near term/short range timeframe will be gradually cooling closer to normal by early next week. Some periods of precipitation are possible for the Aleutians and Alaska Peninsula, but below hazardous criteria. Heavier precipitation amounts with the possibility for coastal rain and inland snow are possible for southeastern parts of the Alaska Panhandle around Wednesday as moisture increases there.
(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
New Feature – Ski Reports. (We may be a tad premature but not by much). It is difficult to find reports that auto-update on-screen (and they are very long) but these links will get you to them – If you have additional suggestions make them in the comments section after every GEI Article and we may add those links. We will try to not have too much overlap as that can add to the confusion.
We will update the above map (or maps) weekly (or more often when the situation is changing rapidly) but more frequent updates can be obtained here.
Snow Forecasts.
Day 1
Day 2
Additional snow information can be found here and here.
We also include drought information in this section.
More information can be found here.
April Drought Outlook..
Seasonal Outlook Issued April 15, 2021
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Tropical Events
I am replacing the large with three small maps but you can click on them to get larger versions. Even though they are small maps you should be able to tell if there is activity and If I see activity I will make the map where there is activity full size and when available add other related maps. Sorry for any confusion but the NHC maps do not update during the Winter except if there is activity. We leave them in simply because if there is a storm NOAA will start to update the relevant map even though it is not normally updated during the off season. The maps are a bit small but if you click the map you can see the date and time when it was updated.
| the Central Pacific. | the Eastern Pacific | the Atlantic and the Gulf of Mexico |
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Atlantic and Gulf of Mexico
The Eastern Pacific
NA
The Central Pacific
NA
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
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And then Precipitation
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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. |
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Here are the precipitation forecasts. First the cumulative for Days 1 – 3
Then cumulative for Days 1 – 5
Then cumulative for Days 1 – 7
Now we look at the forecast for the Maximum Temperature three days out.
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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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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