Written by Sig Silber

HEADLINES –

– Unsettled weather continues over the Northwest

– Light to moderate late effect snow is likely downwind of the Great Lakes

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.

Directory

CONUS Focal Points

Short Range Focal Points

Short Range Forecast Discussion NWS Weather Prediction Center College Park MD – 300 AM EST Mon Nov 16 2020

Valid 12Z Mon Nov 16 2020 – 12Z Wed Nov 18 2020

…Unsettled weather continues over the Northwest…

…Light to moderate late effect snow is likely downwind of the Great Lakes…

Over the Northwest, precipitation is expected to continue today, especially over Washington as a moisture plume takes aim at the state. Additional snow totals are forecast to be over 6 inches for higher elevations of the Cascades, while lower elevations should see rain. This evening and tonight, a brief break in precipitation is likely ahead of an approaching upper-level trough and cold front that will move eastward on Tuesday and spread more precipitation to the region. The Pacific Northwest, the northern half of California, and the Great Basin to Northern Rockies can all expect increasing precipitation chances and eventually lowering snow levels behind the cold front by Wednesday. The Sierra Nevada has Winter Weather Advisories and Winter Storm Watches in place for snow potential. High Wind Warnings and Wind Advisories are also scattered throughout the West.

On the other side of the CONUS, lake effect showers are forecast downwind of the Great Lakes through Tuesday given a favorable upper-level pattern and a cold front passing through tonight. Favored areas east of Lakes Ontario and Erie will likely see at least a few inches of snow. Light snow is also possible for the Central Appalachians, while the northern Mid-Atlantic and Northeast may see non-accumulating snow on Tuesday. Most other areas of the U.S. should remain dry for the next couple days, with the exception of rain showers over the Florida peninsula as a cold front slowly traverses the state.

An upper-level ridge is expected to build in the western and central U.S. ahead of the trough incoming toward the Northwest, underneath which temperatures should warm to above normal by 10 to 20 degrees for much of the West toward the Plains. A handful of record highs could occur in the Southwest and California over the next couple of days as temperatures rise into the upper 80s. Additionally, an Elevated Risk of fire danger is in place across portions of southern California given the warm and dry conditions. Meanwhile in the East, temperatures are expected to cool through midweek behind a cold frontal passage.

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 OR SIMPLY CLICK ON THE IMAGE.

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Day 3 – 7 Hazards

Valid Monday November 16 2020 – Friday November 20 2020

Hazards:

– Heavy precipitation across portions of California, the Pacific Northwest, and the Northern Great Basin, Tue-Fri, Nov 17-Nov 20.

– Heavy rain across portions of California and the Pacific Northwest, Tue-Thu, Nov 17-Nov 19.

– Heavy snow across portions of the Pacific Northwest and the Northern Great Basin, Mon-Fri, Nov 16-Nov 20.

– Heavy snow across portions of the Northern Rockies and the Northern Great Basin, Tue-Fri, Nov 17-Nov 20.

– Heavy snow across portions of the Central Rockies, the Central Great Basin, the Northern Rockies, and the Northern Great Basin, Wed-Fri, Nov 18-Nov 20.

– Heavy snow across portions of the Central Rockies and the Central Plains, Fri, Nov 20.

– Flooding possible across portions of the Mid-Atlantic and the Central Appalachians.

– Flooding occurring or imminent across portions of the Southeast and the Mid-Atlantic.

– Flooding likely across portions of the Mid-Atlantic.

– High winds across portions of the Pacific Northwest, Mon-Tue, Nov 16-Nov 17.

Detailed Summary:

The upper level pattern during the medium range can be summarized with a large long-wave trough situated over the northeast Pacific, a strengthening ridge over the Southwest and Great Plains, and a trough over the Northeast the first half of the week. Warm air advection and large scale upper level divergence supports a wet and active pattern over the Pacific Northwest. The most prominent storm system is a strong surface low forecast to take aim at the west coast of Washington and British Columbia late Monday into Tuesday. Along with heavy coastal/valley rain and mountain snow, the immediate coastline could be subjected to strong winds. The persistent moist onshore flow will keep mountain snow and valley rainfall in the forecast from northern California to the International border most of the period. By mid-late week, Pacific moisture will reach the northern and central Rockies which leads to the opportunity for heavy mountain snow.

Temperature hazards appear to be short of reaching any thresholds but it is worth noting the medium range can expect 5-day temperature anomalies of 8-12 degrees above normal in parts of the Southwest and Plains. These temps are quite warm for this time of year but not to levels that could be deemed “hazardous”. Meanwhile, portions of the Ohio Valley and Mid-Atlantic may witness their first freeze of the season Wednesday and/or Thursday morning. However, the cold shot is a glancing one and not overly-frigid for mid-November, so no below normal temperature area has been issued at this time.

Over Alaska, a cold surface high pressure dominates the mainland with temperatures remaining below normal into the middle of the week. By the second half of the week, a big warm-up over northern Alaska and along the western coast leads to the return of above normal temperatures. The next notable low pressure system should be moving through the Aleutians by midweek. As that storm occludes, a new low may form near Kodiak Island and drift east. Expect wet conditions from the Aleutians and along the southern mainland coast Wednesday and Thursday to potentially reach the Panhandle late week. Precipitation totals and confidence in the storm’s timing/track are not high enough to include a heavy rain/precipitation 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 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 November Drought Outlook

Seasonal Outlook Issued October 15, 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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