Written by Sig Silber

HEADLINES (Updated 4:25 PM EST) –

– Heavy snow for Iowa, Southern Wisconsin, and West-Central Michigan

– Rain/Freezing rain from the Central Plains into the Midwest; Heavy Rain in Deep South

– Heavy snow for the Cascades and the Northern Intermountain Region

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 – 306 PM EST Tue Dec 29 2020

Valid 00Z Wed Dec 30 2020 – 00Z Fri Jan 01 2021

…Heavy snow for Iowa, Southern Wisconsin, and West-Central Michigan…

…Rain/Freezing rain from the Central Plains into the Midwest; Heavy Rain in Deep South…

…Heavy snow for the Cascades and the Northern Intermountain Region…

An amplified upper-level trough which is currently diving through northwestern Mexico will cross the Sierra Madre and eventually spawn a new surface low pressure system Thursday evening. As the upper-level trough expands, and eventually splits, it will stretch the surface low pressure system out from the Central Plains and into the Great Lakes region tonight. Heavy snow is expected to spread from the Great Plains into the Upper Midwest/Great Lakes through Wednesday, where 4-8 inches of snow is likely with the possibility of localized amounts exceeding 8 inches. Ice is expected from the Middle Mississippi Valley into the Midwest with up to 0.1 inches of ice possible to accumulate around the Iowa-Illinois border. Winter Storm Advisories and Warnings are currently in effect from the Plains into the Midwest. Tonight, scattered to isolated thunderstorms are expected to spread from the Central/Southern Plains to the Midwest and Mississippi Valley tomorrow and eventually the eastern third of the country on Thursday. A Slight Risk of Excessive Rainfall leading to Flash Flooding is in effect for parts of the Southern Plains and Lower Mississippi Valley on Wednesday.

Heavy snow is likely to develop over western Texas tomorrow as cold air surges south on the backside of the system. Between 4-8 inches of snow is likely to fall over this area through Thursday. As the Upper-level trough splits into two distinct pieces of energy, the northern stream will weaken while the southern stream develops a new system over the Southern Plains. The northern stream will produce some snow and rain over the Lower Great Lakes and Northeast Wednesday night into Thursday, while the southern stream is likely to continue pulling Gulf moisture and producing heavy rain from the Southern Plains to the Lower/Middle Mississippi and Tennessee Valleys on Thursday. A Slight Risk of Excessive Rainfall is in effect over parts of the aforementioned area as a result.

Meanwhile, heavy snow and rain will impact the Pacific Northwest as a deep area of low pressure approaches the region on Wednesday. Up to 2 feet of snow may fall over parts of the Cascades with isolated amounts exceeding that figure possible. Around a foot of snow is likely over parts of the Northern Rockies during this period as well.

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 20 hour animation and some other views can be found here

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Day 3 – 7 Hazards

Valid Friday January 01 2021 – Tuesday January 05 2021

Hazards:

– Heavy precipitation across portions of the Pacific Northwest and the Northern Great Basin, Fri-Sun, Jan 1-Jan 3.

– Heavy precipitation across portions of California, the Central Great Basin, the Pacific Northwest, the Northern Great Basin, and the Southwest, Mon-Tue, Jan 4-Jan 5.

– Heavy precipitation across portions of the Northeast, the Central Appalachians, the Middle Mississippi Valley, the Mid-Atlantic, the Upper Mississippi Valley, the Great Lakes, and the Ohio Valley, Fri, Jan 1.

– Heavy rain across portions of the Southeast, the Mid-Atlantic, and the Southern Appalachians, Fri-Sat, Jan 1-Jan 2.

– Heavy rain across portions of the Mid-Atlantic and the Northeast, Fri, Jan 1.

– Heavy snow across portions of the Northern Rockies and the Northern Great Basin, Sat-Sun, Jan 2-Jan 3.

– Heavy snow across portions of the Northern Great Basin, Sun-Mon, Jan 3-Jan 4.

– Heavy snow across portions of the Northern Rockies, Sun, Jan 3.

– Heavy snow across portions of the Central Plains, the Middle Mississippi Valley, the Great Lakes, and the Upper Mississippi Valley, Fri, Jan 1.

– Heavy snow across portions of the Northeast, Sat, Jan 2.

– Severe weather across portions of the Southeast and the Mid-Atlantic, Fri, Jan 1.

– Flooding possible across portions of the Middle Mississippi Valley and the Ohio Valley.

– Heavy precipitation across portions of the Alaska Panhandle, Fri-Sat, Jan 1-Jan 2.

– High winds across portions of the Aleutians, Fri, Jan 1.

– High significant wave heights for coastal portions of the Aleutians, Fri, Jan 1.

Detailed Summary:

A pretty active weather pattern will usher in the New Year for much of the eastern half of the country and the Pacific Northwest. Starting in the east, a storm system will track from the south-central Plains into the upper Midwest during Friday, then push into New England on Saturday. To the west of the storm track, a narrow band of moderate to heavy snow is possible, with the current guidance suggesting that it extends from northeastern Kansas across southern Iowa and Wisconsin, and northern sections of the lower peninsula of Michigan. Precipitation may be mixed with sleet and freezing rain at times over parts of this region, which would limit the total accumulations. Farther east through the lower Great Lakes, Mid-Atlantic states and southern New England, Friday will feature a period of mixed precipitation at the start of the event, but changing over to rain as warmer air from the south infiltrates. Cold-air damming may prolong the period of freezing rain/sleet over central/eastern Pennsylvania into New York and southern New England. At this time, a cool rain is expected over the major metro areas of Philadelphia and New York City. Along the trailing cold front, heavy rainfall and the potential for severe weather exists over the southeast, mainly across South Carolina, Georgia, and the Florida Panhandle on Friday.

On Saturday as the low shifts into New England, there’s a chance for heavy snow across the northern half of Maine as the cold air remains locked in place. The trailing cold front will remain active with showers and thundershowers possible over the eastern Carolinas, southeast Georgia, and the northern Florida Peninsula. One area of high uncertainty is the degree that low pressure develops along this front later Saturday-Sunday. Several models show a fairly well-defined low moving through the Mid-Atlantic states early Sunday, then strengthening off the east coast as it tracks up along the southern New England coast. If this scenario were to play out, the potential exists for an area of moderate to heavy snowfall over sections of eastern New York into southern New England late weekend into early next week.

The other region of unsettled weather in the lower 48 will be across the Pacific Northwest, northern California, and the northern Intermountain region. A parade of storm systems will impact the region with heavy coastal/valley rainfall and snow at the higher elevations. On Friday, a front will cross the region, with the heaviest precipitation mostly confined to Washington and Oregon from the Cascades westward. A more substantial system with deeper moisture and stronger onshore flow will move in later Saturday through early Sunday, affecting much of the same area, but with notably higher amounts (locally 2-4′). This system will also bring moderate to heavy snowfall across the higher elevations in northern and central Idaho and eventually the Tetons in western Wyoming. There will be a relative respite Sunday evening into Monday morning before another front slams onshore. However, expect the heaviest precipitation to spread farther down the west coast into northern/Central California. The models then support potentially yet another storm for Tuesday impacting the Pacific Northwest.

Over Alaska, the main story will be the extremely intense cyclone that will track into the north-central Pacific later this week. The primary impacts will be over the western and central Aleutians where high winds and seas will predominate Thursday-Friday. Conditions will improve over the weekend as this low weakens. Farther east, the same series of storm systems impacting the Pacific Northwest will take aim at the southern part of the Panhandle. While precipitation is likely throughout the Day 3-7 period, the front with the deepest moisture is expected to produce the most significant amounts Friday-Saturday.

(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 weekly 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.

New December Drought Outlook

Seasonal Outlook Issued November 19, 2020

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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.

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

Atlantic and Gulf of Mexico

And the Eastern 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

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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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