Written by Sig Silber

HEADLINES (Updated 4:39 pm and 7:04 pm EDT) –

– A developing slow moving tropical storm will threaten the Texas Gulf Coast late this weekend into next week

– Much needed rains on tap Friday night into Saturday for the Pacific Northwest into the Northern Rockies. Flash flooding and debris flows possible over burn scars

– Dry conditions, fire weather threat and poor air quality to continue across California

– Below average temperatures this weekend for areas east of the Mississippi River

– Frosts likely Saturday and Sunday morning from the Great Lakes into the Northern Mid-Atlantic, western and Upstate New York and interior New England

– Above average temperatures expected from the Southwest into the Central and Northern Plains

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.

Directory

CONUS Focal Points

Short Range Focal Points

Short Range Forecast Discussion NWS Weather Prediction Center College Park MD – 308 PM EDT Fri Sep 18 2020

Valid 00Z Sat Sep 19 2020 – 00Z Mon Sep 21 2020

…A developing slow moving tropical storm will threaten the Texas Gulf Coast late this weekend into next week…

…Much needed rains on tap Friday night into Saturday for the Pacific Northwest into the Northern Rockies. Flash flooding and debris flows possible over burn scars.…

…Dry conditions, fire weather threat and poor air quality to continue across California…

…Below average temperatures this weekend for areas east of the Mississippi River…

…Frosts likely Saturday and Sunday morning from the Great Lakes into the Northern Mid-Atlantic, western and Upstate New York and interior New England…

…Above average temperatures expected from the Southwest into the Central and Northern Plains…

A developing tropical system over the southwest Gulf of Mexico is expected to move very slowly over the weekend. An initial slow northward movement Friday night into Saturday will be followed by an equally slow westward movement for the remainder of Saturday and Sunday. This storm has the potential to be a prolific rain producer for the Texas Gulf coast beginning Sunday and possibly continuing into much of next week across the western Gulf coast given the expected slow movement. In addition to the very heavy rain potential, high winds and storm surge will also be a threat along the western Gulf Coast.

Much needed rains are expected to fall Friday night into Saturday across portions of the Pacific Northwest into the Northern Rockies. While these rains will bring some relief from the recent fires and hazardous air quality, they will also pose a of threat of flash flooding and debris flows across the recent burn scar regions.

No relief from the dry weather farther to the south across California where a fire weather threat and hazardous air quality from ongoing fires will continue through the weekend.

Above average temperatures will continue this weekend from the Southwest, across the Great Basin, Rockies and into the Central and Northern Plains. Below average temperatures likely this weekend for nearly all areas to the east of the Mississippi River. Frosts are likely both Saturday and Sunday morning from the Great Lakes into the Northern Mid-Atlantic, western and Upstate New York and interior New England.

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.

– Return to Directory

Day 3 – 7 Hazards

Hazards:

– Heavy rain across portions of the Pacific Northwest and the Northern Great Basin, Wed-Thu, Sep 23-Sep 24.

– Heavy rain across portions of the Southeast, the Lower Mississippi Valley, and the Southern Plains, Mon-Fri, Sep 21-Sep 25.

– Flooding possible across portions of the Southeast, the Mid-Atlantic, and the Southern Appalachians.

– Flooding occurring or imminent across portions of the Southeast and the Southern Appalachians.

– Flooding likely across portions of the Southeast and the Southern Appalachians.

– Much above normal temperatures across portions of the Central Plains, the Upper Mississippi Valley, the Northern Plains, and the Northern Rockies, Thu-Fri, Sep 24-Sep 25.

– Much above normal temperatures across portions of the Central Plains, the Middle Mississippi Valley, the Upper Mississippi Valley, and the Northern Plains, Mon-Tue, Sep 21-Sep 22.

– Much below normal temperatures across portions of the Northeast, the Central Appalachians, the Tennessee Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, the Great Lakes, and the Ohio Valley, Mon-Tue, Sep 21-Sep 22.

– Much below normal temperatures across portions of the Mid-Atlantic, the Northeast, and the Great Lakes, Mon, Sep 21.

– High significant wave heights for coastal portions of the Southern Plains, Mon-Thu, Sep 21-Sep 24.

– Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Mon-Tue, Sep 21-Sep 22.

– Heavy precipitation across portions of the Alaska Panhandle, Tue-Wed, Sep 22-Sep 23.

– High winds across portions of the Alaska Panhandle, Tue-Wed, Sep 22-Sep 23.

Detailed Summary:

The medium range period (Monday, Sep 21 – Friday, Sep 25) features a pair of deep upper level troughs over the northeast Pacific and off the Northeast coast, while ridging aloft sets up over the Northern Plains. The start of the period calls for a couple more days of much below normal temperatures in parts of the Northeast and Mid-Atlantic. Daily mean temperature anomalies look to hover around 12 degrees below normal and some daily record cold lows and highs are also expected. Patchy areas of frost are also likely Monday and Tuesday morning over the interior Northeast and northern Mid-Atlantic. Temperatures will moderate to near normal levels the second half of the week as the air-mass modifies and a milder regime moves in from the Upper Midwest. While the East Coast sees the return of typical September-like temps, a more late summer-like trend develops in the Northern Plains as upper-level ridging builds in aloft. Parts of the North-Central U.S. can anticipate an abnormally warm start to the week with another round of much above normal temperatures possible late week in the northern Rockies and Plains. Precipitation-wise, the large upper trough over the northeast Pacific sends a swath of beneficial precipitation towards the drought-stricken Pacific Northwest. Several inches of rainfall are possible in the Olympics and Cascades.

While much of the Lower 48 can expect drier than normal conditions overall, the water hazards during the medium range period are highlighted by Tropical Storm Beta in the western Gulf of Mexico. Beta poses a significant flood threat stemming from Brownsville on north through the upper Texas coast and into southwest Louisiana. Beta is forecast to become a hurricane this weekend and weaken as it ingests dry air from a cold front approaching from the north and west next week. While the storm’s intensity drops to a degree, the storm becomes caught between three areas of ridging: one in the tropical East Pacific, one over the north-central U.S., and another over Florida. This causes weak steering flow that forces the storm to meander near the Texas coast. Exactly where it sets up along the coast will determine which locations receive heavy rainfall, for how long, and where the worst coastal impacts occur. Given the opportunity for multiple days of brisk onshore flow, storm surge and coastal flooding are concerns along the northwest Gulf Coast. A significant waves hazard has been drawn along the Texas coast to account for these coastal threats. There is also the potential for tropical storm force winds, most notably on the northern and northeastern flanks of the storm, but confidence in which locations experience those wind hazards remain unclear since Beta could remain more offshore. Confidence in the forecast beyond day 5 is low, but there is ensemble guidance that suggests Beta could head northeast and bring the heavy rain threat to parts of the western Louisiana and the Lower Mississippi Valley late next week. Major Hurricane Teddy, meanwhile, will be closely monitored for potential coastal hazards and strong winds near the New England coast. Currently, the strongest wind speeds look to remain offshore and wave heights are forecast to remain below threshold but this could change should the storm come closer to the New England coast.

The busy weather pattern across Alaska refuses to back down through next week. A powerful storm system is forecast to pass over the Alaskan Peninsula Monday and across the Gulf of Alaska through late week. Gusty winds are possible over the Aleutians, as well as potentially across south-central Alaska, though it will depend on the exact low track. High winds are most likely for southern coastal parts of the Panhandle Tuesday into early Wednesday, but some locally high winds are also possible along the Gulf Coast and near Kodiak Island. The most widely observed hazard with this system will be heavy precipitation from the Alaska Peninsula toward the Kenai Peninsula the first half of the week, then reaching the Panhandle mid-week. Heavy snow accumulations are anticipated in the higher elevations along the coast. Precipitation should remain primarily in the form of rain throughout most of the Panhandle, and heavy rain is forecast to begin late Tuesday and persist through Thursday. There is the potential for yet another area of low pressure to usher in more rainfall to the Panhandle next Thursday and Friday, but confidence in totals meeting heavy rainfall criteria are low 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.

– Return to Directory

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.

During the summer we might add some drought information in this section.

New Seasonal Outlook Issued August 20, 2020

– Return to Directory

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

– Return to Directory

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

– Return to Directory

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.

– Return to Directory

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.

– Return to Directory

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.

– Return to Directory

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

– Return to Directory