Written by Sig Silber

Updated at 5:40 pm EDT Saturday May 9, 2020 – “…Arctic blast to engulf the eastern U.S. with cold, gusty, and wintry conditions over Mother’s Day Weekend……Toasty Mother’s Day Weekend for the West Coast, Great Basin, and Southwest……Storm system to generate showers, storms, and some snow from the Midwest to the Appalachians, heavy rain and storms possible in South Florida…”

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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CONUS Focal Points

Short Range Focal Points

Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Sat May 09 2020 Valid 00Z Sun May 10 2020 – 00Z Tue May 12 2020

…Arctic blast to engulf the eastern U.S. with cold, gusty, and wintry conditions over Mother’s Day Weekend…

…Toasty Mother’s Day Weekend for the West Coast, Great Basin, and Southwest…

…Storm system to generate showers, storms, and some snow from the Midwest to the Appalachians, heavy rain and storms possible in South Florida…

A blast of chilly air, gusty winds and a mix of rain and snow can be expected across parts of the Upper Mississippi Valley, Great Lakes and Northeast regions this weekend as a low pressure system moves east from the Central Plains to the East Coast. Some thunderstorms could be severe in the Lower Great Lakes Sunday afternoon. The chance for showers will push into the Mid-Atlantic and Northeast on Monday with some snowfall possible in the central Appalachians. There are numerous Freeze Watches, Warnings, and Frost Advisories are in effect through Sunday morning across the Central High Plains, Northern Plains, and from Alabama to the Northeast. Many daily temperature records are expected to be tied or broken this weekend– with record low max and min temperatures across much of the East today and more record lows in the Southeast and Mid-Atlantic by Mother’s Day morning. Newly bloomed vegetation, as well as, sensitive flower and vegetable gardens may sustain damage if left uncovered in these near or below freezing temperatures. Winter Storm Warnings and Winter Weather Advisories are in effect for a large portion of Maine as a coastal low spins develops with this system and spreads scattered rain and snow along its path. Surface high pressure will slide into the central U.S. from Canada and keep the cooler airmass in place.

Across the West, much warmer weather is in store with summer-like temperatures. Many locations along the West Coast will have afternoon highs reaching the 80s and 90s, which may break daily max and min temperature records. Mother’s Day will feature slightly less intense heat across the western third of the U.S. but still range between 10 and 20 degrees above normal. Temperatures are expected to moderate early in the coming week as a Pacific storm system approaches the coast. Sunday looks to be to be a wet across South Florida and the Keys as moisture streams along a stalled frontal boundary overhead. Thunderstorms in South Florida on Sunday could be severe and produce heavy downpours. Rain amounts across this area will average 2 to 4 inches by Monday.

Click here for the latest complete NWS/WPC Short Range Discussion. (Sometimes we provide part of or even the full discussion above and you can tell because it goes beyond the bullet points. We do that when we think the bullet points do not provide enough information. But the link just provided always takes you to the full discussion with updates twice a day and sometimes we are a bit late updating the bullet points so that link will get you there. You can tell if we are late by the time of the stamped update. This time of the year, NOAA does the updates at around 3 a.m. and 3 p.m. EST. We try to do the updates in our article as close to that as possible but it is not always possible.)

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.

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

Water Vapor.

This view of the past 24 hours provides a lot of insight as to what is happening.

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Day 3 – 7 Hazards

– Heavy rain across portions of California and the Pacific Northwest, Mon-Tue, May 11-May 12.

– Heavy rain across portions of the Central/Southern Plains, the Mississippi Valley, the Great Lakes, and the Ohio Valley, Mon-Fri, May 11-May 15.

– Heavy rain across portions of the Southeast, Mon-Thu, May 11-May 14.

– Flooding possible across portions of the Northern Plains.

– Flooding occurring or imminent across portions of the Middle/Lower Mississippi Valley, the Great Lakes, and the Northern Plains.

– Flooding likely across portions of the Northern Plains.

– Much above normal temperatures across portions of the Central Great Basin, the Northern Rockies, and the Northern Great Basin, Mon, May 11.

– Much below normal temperatures across portions of the Plains, the Mississippi Valley, the Tennessee Valley, the Ohio Valley, the Central/Southern Appalachians, the Great Lakes, the Mid-Atlantic, and the Southeast, Mon-Tue, May 11-May 12.

– Much below normal temperatures across portions of the Northeast, the Central/Southern Appalachians, the Mid-Atlantic, the Upper Mississippi Valley, the Great Lakes, and the Ohio Valley, Mon-Wed, May 11-May 13.

– Much above normal temperatures across portions of mainland Alaska, Mon, May 11.

– Much above normal temperatures across portions of mainland Alaska, Mon-Tue, May 11-May 12.

Detailed Summary:

The medium range period will begin on Monday 5/11 with below normal upper-level heights persisting across central and eastern parts of the U.S., as a potent upper trough settles overhead with shortwave troughs progressing through. This will lead to continued below normal temperatures on Monday and Tuesday, with many record low maximum and minimum temperatures forecast from the Central/Southern Plains to the Northeast. Late frosts and freezes are expected in some areas. Temperatures should remain cool from the Midwest/Great Lakes to the Mid-Atlantic/Northeast through midweek underneath a surface high pressure system, but upper-level troughing will relax farther south and west, bringing temperatures to about normal in the Southern Plains and Gulf Coast states after Tuesday.

Meanwhile over the West, an upper-level ridge over the Great Basin on Monday should shift eastward and relax during the workweek. Above normal temperatures are expected under the ridge, and a few record high minimum temperatures could be set Monday. An upper-level low is forecast to approach the West on Monday and Tuesday, cooling down temperatures and leading to precipitation in the Pacific Northwest and northern California. Heavy rain is possible, with the best chance currently across northwestern California and southwestern Oregon. But some precipitation is forecast all across the Pacific Northwest toward the Cascades and Sierra Nevada, then spreading into the Northern Great Basin and Northern Rockies by Tuesday and Wednesday. Lower elevation precipitation should fall as rain, but higher elevations could see a few inches of snow.

A couple of frontal systems are expected to linger near southern Florida next week, leading to the potential for multiple rounds of locally heavy rain. Another area where heavy rain is possible is from the Central/Southern Plains toward the Mississippi and Ohio Valleys, as moisture interacts with a stationary front to the south which then becomes a warm front around midweek. Currently, rain and thunderstorms are currently forecast to spread from the Plains Monday and Tuesday northeastward to the Middle Mississippi Valley Wednesday and portions of the Ohio Valley Thursday. Then as a front pushes back southward, the Southern Plains could have another round of heavy rain by Friday. However, the timing and details like the extent (especially the eastward extent) and magnitude of the heavy rain are still uncertain and should continue to be monitored.

Over Alaska, much above normal temperatures are forecast to continue over portions of the mainland for the early part of the week, underneath upper-level ridging and south of the influence of the Arctic surface high pressure system over the North Slope. Temperatures should moderate from midweek on, though still remaining somewhat above normal over southern and western portions of the mainland in particular. Ice jam and snowmelt flooding will continue to be threats across some areas of the mainland where rivers have not yet opened up, particularly the Middle Yukon River.

(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. 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 weekly but more frequent updates can be obtained here.

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Tropical Events

This is now beyond the time of the year we pay special attention to Tropical Events other than the Western Pacific.

So 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.

the Central Pacific.	the Eastern Pacific	the Atlantic and the Gulf of Mexico

Updates on individual named storms can be obtained here.

And the Western Pacific

Week 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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