Written by Sig Silber

HEADLINES (Updated 4:53 PM EDT) –

– Heavy rain and severe thunderstorms possible from the Southern Plains to the Ohio Valley through Thursday

– Fire danger narrows to the Southern/Central High Plains this evening

– Above average temperatures to be found across both the eastern and western United States

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 319 PM EDT Tue Apr 27 2021

Valid 00Z Wed Apr 28 2021 – 00Z Fri Apr 30 2021

…Heavy rain and severe thunderstorms possible from the Southern Plains to the Ohio Valley through Thursday…

…Fire danger narrows to the Southern/Central High Plains this evening…

…Above average temperatures to be found across both the eastern and western United States…

A busy spring weather pattern is in store for the central U.S. and portions of the East over the next few days. The focus for the active weather will be driven by an upper-level low currently located over the Southwest and a slow-moving frontal boundary that extends from the Northeast to the southern High Plains. The biggest weather hazard associated with this system will be multiple days of thunderstorms and heavy rain that will extend across a large section of the country from Texas to the Ohio Valley.

The Storm Prediction Center has issued a slight risk of severe thunderstorms for three separate areas this evening. The areas of concern include central Wisconsin, portions of northeast Colorado, southwest Nebraska, and northwest Kansas, as well as much of the Southern Plains from south-central Texas to western Missouri. Damaging wind gusts and large hail may accompany the developing thunderstorms, with isolated tornadoes possible across the Southern Plains and central High Plains. Heavy rain could also lead to isolated flash flooding in these regions tonight. Meanwhile, high elevation snow is expected to continue across the central and southern Rockies through Wednesday afternoon. Winter Storm Warnings remain in effect across north-central Colorado for snow accumulations up to 12 inches.

As the frontal boundary slowly inches eastward on Wednesday, additional thunderstorms and multiple rounds of heavy rain are forecast to occur from the Southern Plains to Ohio Valley. The best chance for severe weather will be confined to central Texas and Oklahoma, where SPC has highlighted the region as having a slight risk of severe thunderstorms.

However, thunderstorms will impact other areas and are likely to bring summer-like downpours across the Ohio and Lower/Middle Mississippi valleys. Thus, WPC has issued a Slight Risk of Excessive Rainfall across a large area from southwest Ohio to south-central Texas. Through Thursday night, as much as 2 to 4 inches of rain could fall across this region, with locally high amounts possible. This could lead to instances of scattered flash flooding for locations that receive multiple rounds of heavy rain.

Elsewhere across the Lower 48, much of the West, Mid-Atlantic, and Southeast will remain dry through Thursday. High temperatures will soar 10 to 20 degrees above average and into the 80s on Wednesday and Thursday throughout the Mid-Atlantic and interior Northwest. Fire weather will also remain a concern through this evening across the southern and central High Plains, where Red Flag Warnings have been issued.

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 Friday April 30 2021 – Tuesday May 04 2021

Hazards:

– Flooding possible across portions of the Central Plains, the Middle Mississippi Valley, the Lower Mississippi Valley, the Southern Plains, and the Ohio Valley.

– Flooding occurring or imminent across portions of the Lower Mississippi Valley.

– Flooding likely across portions of the Lower Mississippi Valley.

– Much above normal temperatures across portions of the Central Plains, the Central Great Basin, the Northern Plains, the Northern Rockies, the Central Rockies, California, the Northern Great Basin, the Pacific Northwest, and the Southwest, Fri-Sat, Apr 30-May 1.

– Much above normal temperatures across portions of the Central Plains, the Central Rockies, the Central Great Basin, the Northern Plains, the Southern Rockies, the Middle Mississippi Valley, the Upper Mississippi Valley, the Southern Plains, and the Southwest, Sat-Sun, May 1-May 2.

– Heavy precipitation across portions of the Alaska Panhandle, Fri, Apr 30.

Detailed Summary:

This upcoming medium range period (Friday, April 30 – Tuesday, May 4) will feature a progressive pattern over the continental U.S. with initially very strong upper level systems gradually deamplifying into a more east-west zonal flow. The upper trough that’s currently impacting the southwestern states will move steadily eastward over the next couple of days and in its wake, a strong ridge will build in during the latter part of the week. As a result, there’s going to be a pretty big temperature swing from below normal temperatures to much above normal readings over the West, which will eventually overspread much of the central U.S. during the weekend.

High temperatures on Friday and Saturday will range from 15-20 degrees above normal from the southwestern states through the Great Basin, northern Rockies and out into the northern Plains. Record highs in the 80s to low-mid 100s are possible Friday from the Great Basin into western Arizona and inland sections of central-southern California, with additional records possible Saturday over the desert Southwest.

The ridge is going to start flattening out over the weekend, so while above normal temperatures will push eastward into the central and southern Plains over the weekend, the positive anomalies won’t be as significant. Triple-digit heat will develop over southern sections of Texas early next week, but with dew points relatively low, heat indices are not expected to be excessive.

A big forecast challenge for this period is determining where there may be areas of organized heavy rainfall. A piece of the trough that’s over the Southwest may get left behind over northern Mexico/southern Texas later this week and only slowly advance across the Gulf Coast states during the weekend. There has not been good agreement among the models with this feature, but if it evolves in this manner, there is the potential for heavy rainfall across the Texas Gulf Coast eastward into the lower Mississippi Valley. The problem is that the large variety of solutions makes it quite difficult to pinpoint where heavy rain may fall, so will hold off drawing a hazard area and re-evaluate this system tomorrow.

Over Alaska, a series of short waves and associated surface features rotating around a Gulf of Alaska low will bring copious amounts of Pacific moisture into the central and southern Panhandle later this week. The main slug of moisture and heaviest precipitation will likely be in the Day 2-3 timeframe, but a trailing trough will support another round of at least moderate precipitation on Friday. Conditions should generally improve over the weekend.

(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

Atlantic and Gulf of Mexico

Nothing to report

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

And then Precipitation

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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

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

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
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

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