Written by Sig Silber
HEADLINES (Updated 4:27 pm and 9:15 pm EDT) –
– Temperatures will be 10 to 20 degrees above average over the West Coast and 10 to 15 degrees below average over the Upper Midwest
– Air quality alerts, red flag warnings, and heat advisories extend from parts of the West Coast to the 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.
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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 Forecast Discussion NWS Weather Prediction Center College Park MD – 402 PM EDT Wed Sep 30 2020
Valid 00Z Thu Oct 01 2020 – 00Z Sat Oct 03 2020
…Temperatures will be 10 to 20 degrees above average over the West Coast and 10 to 15 degrees below average over the Upper Midwest…
…Air quality alerts, red flag warnings, and heat advisories extend from parts of the West Coast to the Plains…
A broad upper-level ridge and associated high pressure at the surface will remain over the West Coast through Friday evening. This will allow temperatures to become 10 to 20 degrees above average over the region. Air quality alerts, red flag warnings, and heat advisories have been posted over the West From the Plains to California. In contrast, a deep upper-level trough extends from east of the Rockies to the East Coast. Embedded in this trough are a few fronts one will linger over the southern tip of Florida producing showers and thunderstorms through Friday evening. Energy moving through the trough will trigger rain and showers over parts of the Upper Midwest to the Mid-Atlantic/Northeast trough Friday. Some of the rain will be mixed with snow over parts of the Upper Great Lakes on Thursday into Friday. Beneath the upper-level trough, temperatures will be 10 to 15 degrees below average.
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.
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.
A version that shows a 20 hour animation and some other views can be found here OR SIMPLY CLICK ON THE IMAGE.
– Heavy rain across portions of the Florida Peninsula and North Carolina coast, Sat-Sun, Oct 3-Oct 4.
– Heavy rain across portions of the northern Mid-Atlantic to central and coastal New England, Mon-Tue, Oct 5-Oct 6.
– Flooding occurring or imminent across portions of northeastern Florida.
– Flooding likely across portions of northeastern Arizona.
– Much above normal temperatures across portions of northern California, northern Nevada, and interior Pacific Northwest, Sat-Wed, Oct 3-Oct 7.
– Heavy precipitation across portions of the Alaska Panhandle and southern coast of Alaska, Sun-Mon, Oct 4-Oct 5.
– Heavy precipitation across portions of the Kenai Peninsula, Sat, Oct 3.
At the start of the medium range period (Saturday, Oct 3 – Wednesday, Oct 7), global models show very good agreement that a longwave trough will be the dominant feature across the central to eastern U.S. as an upper-level ridge lingers across the West. However, solutions quickly diverge thereafter as the ECMWF and CMC continue to predict a rather significant low pressure system to develop near the New England coast early next week. On the other hand, the GFS continue to show very little of such development. What the ECMWF and CMC indicate is the phasing of an Alberta clipper with a coastal low forming near the Mid-Atlantic coast. Given the rather amplified upper pattern to start with, it appears that the ECMWF/CMC solutions represent a more reasonable outcome than that of the GFS which shows a gradual weakening of the Alberta clipper as it moves toward the Great Lakes. Therefore, a heavy rain area has been introduced across portions of the northern Mid-Atlantic to central and coastal New England for Monday and Tuesday. In addition, it would be possible that the coastal sections will be impacted by increasing winds and waves depending on the eventual strength of the low pressure system.
Meanwhile, a continued feed of tropical moisture ahead of and along a stalled front will keep a good chance of heavy rain for the central to southern portion of the Florida Peninsula likely through the middle of next week. The National Hurricane Center is also watching the potential for a tropical cyclone to develop and move across the western Caribbean for early next week. In addition, there is increasing model support for a wave of low pressure to form along the stalled front off the Carolina coasts which is forecast to phase with the Alberta clipper as mentioned earlier. This low pressure wave is forecast to bring heavy rain near the coast of North Carolina during the weekend.
Much of the western U.S. will see warmer than average temperatures through the period under the influence of the upper-level ridge. Temperatures across portions of northern California, northern Nevada, and interior Pacific Northwest are forecast to remain more than 12 degrees above normal through the medium-range period. This could keep the fire risk high across these areas. The warm air will then work its way eastward across the Plains behind a warm front early to middle of next week. Meanwhile, the chilly air that covers much of the eastern two-thirds of the country this weekend will gradually moderate to around normal by the middle of next week.
Over Alaska, an active pattern will lead to fast and frequent energetic oceanic cyclones to push onshore across the southern part of the state through early next week. Heavy precipitation will be likely over the Kenai Peninsula on Saturday in association with the first cyclone, spreading eastward into the northern part of the Alaska Panhandle Sunday and Monday associated with the second cyclone. The second cyclone is expected to bring gale-force winds to the coastal sections of southern Alaska on Sunday. By the middle of next week, a strong front could be moving through the Aleutian Islands.
(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.
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.
We also include drought information in this section.
New Seasonal Outlook Issued September 17, 2020
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
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).
And then Precipitation
For those interested in more detail, there are additional weather maps and information in the MORE WEATHER Addendum. The link to the Addendum is here.
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.
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.
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.
|Current watches, warnings, and advisories issued by the agencies of the National Weather Service. Hazards should show up in the various maps but the below links will take you to all outstanding watches and warnings in each category which may include some categories not covered in the various maps or difficult to find. So if there is a category of interest, click on the appropriate link below.|
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.|
|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|