Written by Sig Silber

HEADLINES (Updated 5:54 PM EDT) –

– Some late-season snowfall is expected across the northern Rockies to northern High Plains

– A low pressure system will bring moderate to heavy rain across the Midwest this weekend with severe weather possible across the central Plains toward the lower Mississippi

– Unsettled weather will enter the Pacific Northwest and Northern Great Basin Monday before shifting into the Northern High Plains next Friday

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 405 PM EDT Fri May 07 2021

Valid 00Z Sat May 08 2021 – 00Z Mon May 10 2021

…Some late-season snowfall is expected across the northern Rockies to northern High Plains…

…A low pressure system will bring moderate to heavy rain across the Midwest this weekend with severe weather possible across the central Plains toward the lower Mississippi…

More active weather is forecast to move across the mid-section of the country toward the northeastern U.S. into the weekend as a low pressure system intensifies along a frontal boundary. The low pressure system is currently in its formative stage as it spreads late-season snowfall across the northern Rockies to the nearby High Plains.

As an upper-level trough exits the western U.S. and interacts with the frontal boundary, the low pressure system is expected to intensify more rapidly as it tracks across the central Plains into the Midwest during the weekend. A swath of moderate to heavy rain to expected to expand across the Midwest into the Ohio Valley late Saturday into Sunday, possibly reaching western New York by Sunday evening.

Farther south, severe weather is possible in the central Plains on Saturday, pushing toward the lower Mississippi on Sunday ahead of a cold front. Meanwhile, additional mountain snow is expected across the northern Rockies while showers and some thunderstorms are expected to develop over the central Rockies and High Plains ahead of a warm front.

Farther east, scattered showers and thunderstorms are expected into this evening across the lower Great Lakes and the Mid-Atlantic as a couple of weak low pressure systems move across. Some wet snow is also possible over the higher elevations of the central Appalachians tonight. Rain showers and a few thunderstorms may linger into Saturday afternoon over parts of the Northeast before the weak low pressure systems move out to sea.

In terms of temperatures, broad upper-level troughing will keep temperatures below normal from across the northern tier states to much of the eastern U.S. into Saturday before warm air spreads into the Carolinas on Sunday. Very warm temperatures will also be found across the southern High Plains on Saturday south of the intensifying low pressure system, where fire weather risk is elevated to critical into the southern Rockies. The fire weather risk is forecast to be critical across parts of interior northern California as well on Saturday.

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 Monday May 10 2021 – Friday May 14 2021

Hazards:

– Heavy rain across portions of the Southeast, the Lower Mississippi Valley, and the Southern Plains, Mon-Wed, May 10-May 12.

– Heavy rain across portions of the Southeast, Wed, May 12.

– Heavy rain across portions of the Mid-Atlantic, Thu, May 13.

– Heavy rain across portions of the New England, Fri, May 14.

– Flooding occurring or imminent across portions of the Ohio Valley.

Detailed Summary:

The primary concern through the medium-range forecast period (Monday, May 10th through Friday, May 14th) will be for multiple areas of heavy rain over central and eastern portions of the U.S. A low pressure center will be located over the Mid-Atlantic Monday morning with a trailing cold front through the Southeast to the Southern Plains. The cold front will push to the southeast on Tuesday before stalling north of the Gulf Coast and remain quasi-stationary. Multiple waves of low pressure will move eastward along this boundary across the Southern Plains and into the Southeast through Thursday.

Widespread heavy rain is expected across the Southern Plains and Southeast Monday through Wednesday as these disturbances move eastward and rich Gulf moisture is advected inland, overrunning the quasi-stationary boundary. Opted for one large area for simplicity and to account
for uncertainty in where the heaviest rainfall may fall each day as the disturbances transverse the
boundary. The heavy rain will extend further eastward to include eastern portions of Georgia and
South Carolina on Wednesday as the waves progress to the east and one area of low pressure begins to better organize off the coast of South Carolina. Previous heavy rain across much of the Southern Plains and Southeast has contributed to high soil moisture, leaving many of these areas susceptible to flooding from the additional heavy rainfall through the period. The low pressure center off the Southeast coast will begin to lift to the north along the Atlantic Seaboard Thursday into Friday, passing east of the New England Coast by the end of the period. Heavy rain is likely across eastern portions of the Mid-Atlantic Thursday and into Southern New England and the southwest coast of Maine on Friday as the low passes just offshore.

Elsewhere, cool, moist upslope flow behind the front draped across the South along with a trough of low pressure moving southeastward over the Northern and Central Rockies will lead to the chance for rain across the Central High Plains on Monday. Snow is also forecast for portions of the Central Rockies and it is likely some of the precipitation over the Plains will mix with snow. Due to the mixed nature of the precipitation and expected light nature of any snow accumulations, neither a heavy rain nor snow outlook was included. Higher snow accumulations are possible in southeast Wyoming and into the Colorado Front Range, but should remain below a hazardous threshold and isolated to the higher mountain peaks.

For Alaska, a Pacific storm system will move into the Bering Sea by Thursday, with associated frontal boundaries moving east across the Aleutian Islands and the Gulf of Alaska into Friday. There is an indication that heavy rain is possible with this system from the Aleutian Islands east across the Alaskan Peninsula and into southern mainland Alaska. However, significant differences between the models with respect to both the timing and placement of the heavy rainfall preclude an outlook area 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

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.

May 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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