Written by Sig Silber

HEADLINES (Updated 5:59 PM EST) –

– Heavy snow for the Sierra Nevada Mountains, mountains of the Great Basin, and the Central Rockies Friday through Saturday

– Heavy lake effect snow downwind from Lakes Erie and Ontario through Friday.

– Snow to develop over parts of the Upper Midwest Saturday

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.

Please share this article – Go to the very top of the page, right-hand side for social media buttons. Also, feel free to send this email to anyone you feel will benefit from it.

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 – 226 AM EST Thu Jan 21 2021

Valid 00Z Fri Jan 22 2021 – 00Z Sun Jan 24 2021

…Heavy snow for the Sierra Nevada Mountains, mountains of the Great Basin, and the Central Rockies Friday through Saturday…

…Heavy lake effect snow downwind from Lakes Erie and Ontario through Friday…

…Snow to develop over parts of the Upper Midwest Saturday…

A front extending across the interior Gulf Coast States will have moisture pooling along the boundary and will produce rain from parts of the Southern Plains eastward across the Southeast through Friday.

Meanwhile, a reinforcing cold front will sweep across the Great Lakes tonight, producing favorable cold westerly to northwesterly flow across the unfrozen Great Lakes. Lake-effect snow showers will increase in coverage and intensity this evening and continue through Friday. Locally-heavy snow accumulations are likely with the heaviest totals expected over western and northwestern portions of New York State, downwind from Lakes Erie and Ontario; northern portions of the Lower Peninsula of Michigan, downwind of Lake Michigan; and along the north coast of the Upper Peninsula of Michigan, downwind of Lake Superior through Saturday.

A front over the Pacific Northwest will advance southeastward to the Southwest through Friday and into the Southern Rockies Saturday. The system will produce coastal rain and higher elevation snow over parts of southern Oregon through California and snow across the Intermountain Region into parts of the Northern Rockies through Friday. Later Friday, higher elevation snow will develop over parts of Northern/Central California. The higher elevation snow will expand across the terrain of the Great Basin, Southwest, and Central/Southern Rockies along with lower elevation rain. The rain will also shift into Southern California on Friday evening. By Saturday morning, the rain and snow will end over the Pacific Northwest and most of Northern California, yet continue over Southern California, the Sierra Nevada Mountains, and the Great Basin into the Central/Southern Rockies.

Overnight Friday through Saturday, a front over South-Central Canada will move southward into the Upper Midwest. In conjunction with upper-level dynamics over the Central/Southern Rockies, snow will develop over parts of the Northern/Central Plains into parts of the Upper/Middle Mississippi Valley.

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 Sunday January 24 2021 – Thursday January 28 2021

Hazards:

– Heavy precipitation across portions of Southern California, the Central and Southern Appalachians, the Mid-Atlantic, the Great Lakes, and the Ohio Valley, Mon-Tue, Jan 25-Jan 26.

– Heavy precipitation across portions of the Central Plains and the Middle Mississippi Valley, Mon, Jan 25.

– Heavy rain across portions of California, Wed-Thu, Jan 27-Jan 28.

– Heavy rain across portions of the Lower Mississippi Valley, the Central Appalachians, the Tennessee Valley, the Middle Mississippi Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, the Southern Plains, and the Ohio Valley, Sun-Mon, Jan 24-Jan 25.

– Heavy snow across portions of the Pacific Northwest and the Northern Great Basin, Sun, Jan 24.

– Heavy snow across portions of California, the Central Great Basin, the Pacific Northwest, and the Southwest, Sun-Mon, Jan 24-Jan 25 and Wed-Thu, Jan 27-Jan 28.

– Heavy snow across portions of the Central Great Basin and the Southwest, Mon-Tue, Jan 25-Jan 26.

– Severe weather across portions of the Lower Mississippi Valley and the Southern Plains, Sun, Jan 24.

– High winds across portions of the Aleutians, Tue-Wed, Jan 26-Jan 27.

Detailed Summary:

The medium range period (Sunday, January 24 to Thursday, January 28) will continue to feature a fairly typical January weather pattern, with multiple areas of potentially impactful wintry precipitation. Starting with the end of this upcoming weekend and early next week, upper-level energy is expected to eject out of the Southwest and into the south-central United States. This will help increase moisture transport from the eastern Pacific and western Gulf of Mexico. Combined with an approaching cold front, the expected atmospheric set up will allow for potentially heavy rain from far eastern sections of the Southern Plains, throughout much of the Tennessee and Ohio valleys, as well as into the southern Appalachians. There are high probabilities of greater than 1 inch of rain for these areas, with potential local amounts greater than 2 inches. On the northern periphery of the precipitation shield there is the potential for impactful snow and freezing rain. This includes areas from the Midwest to Northeast. At the moment, confidence is highest across the northern Mid-Atlantic and an area spreading from far northeast Kansas to northwest Illinois regarding impactful wintry precipitation between Monday and Tuesday. A stripe of heavy snow could also stretch between these regions across the Upper Ohio Valley and Lower Great Lakes, but confidence is low on exactly where this occurs. Along and east of the central Appalachians, cold air should remain in place long enough to support snow, sleet, and/or freezing rain from the Shenandoah Valley to central Pennsylvania. Further north, the northern edge of the precipitation shield will likely be sharp and snowfall amounts will drop off significantly across northern Pennsylvania and the Tri-State Region. Be sure to check back for the latest forecast as slight adjustments are likely over the next several days. By next Thursday, forecast models are starting to converge on yet another winter storm threat that could impact the Ohio Valley and Mid-Atlantic. Given it is still seven days out and confidence is low, no areas were added to the hazards chart today.

Much needed precipitation will continue to impact the Southwest and West Coast during the medium range forecast period thanks to a persistent upper-level trough. Heavy snow will be found from the Cascades to the Sierra Nevada between Sunday and Monday. Heavy precipitation will make it as far south as Southern California, with rain along the coast and snow across the Transverse and Peninsular ranges. Heavy snow will also be a concern Monday and Tuesday across the Mogollon Rim in Arizona, as well as higher elevations in Utah and Nevada. By Wednesday, there is the potential for an atmospheric river across northern California that may meander southward by Thursday. This could lead to several feet of snow across the central and northern Sierra if forecast trends continue, with 1 to 2 inches of rain possible in the lower elevations. There is still considerable spread with the location and timing, as the axis of heavy precipitation could be delayed until late Thursday.

Across Alaska, temperatures are forecast to remain well above average throughout western portions of the state Sunday and Monday. By Tuesday, a potent low pressure system is expected to enter the Bering Sea and could produce high winds along the Aleutian Islands through Wednesday.

(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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