Written by Sig Silber
HEADLINES (Updated 10:28 PM EDT) –
– Moderate and Enhanced risk of strong to severe thunderstorms over portions of the central US Thursday and Friday, respectively
– Showers and potentially severe thunderstorms continue in the Northeast before being ushered offshore overnight by a passing cold front
– Cold spell in store for the northern Great Plains, Midwest, and Northeast Thursday into Friday
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.
Readers can scan through this article or jump to where they want to go via the links to the right. To get back to the Directory, hit the back arrow at the top of the URL bar on your screen. But in many cases, one of my Editors has graciously inserted a Return to Directory link to click so that is even easier. This is so high tech that I hardly believe it. |
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CONUS Focal Points
Short Range Focal Points
Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EDT Wed May 26 2021
Valid 00Z Thu May 27 2021 – 00Z Sat May 29 2021
…Moderate and Enhanced risk of strong to severe thunderstorms over portions of the central US Thursday and Friday, respectively…
…Showers and potentially severe thunderstorms continue in the Northeast before being ushered offshore overnight by a passing cold front…
…Cold spell in store for the northern Great Plains, Midwest, and Northeast Thursday into Friday…
Throughout the Great Plains showers and thunderstorms will continue overnight and spread eastward as a low pressure system moves across the central US, deepening along its path. It is expected that several of these thunderstorms will become severe, bringing with them intense damaging winds, very large hail, and potentially strong tornadoes.
At present, the Storm Prediction Center has issued a moderate risk of severe weather for portions of Nebraska and Kansas. In addition to the severe weather threat, heavy downpours from thunderstorms could result in flash flooding.
The Weather Prediction Center has issued a slight risk of excessive rainfall for portions of the central Plains through Thursday morning. As the system progresses east, so will the areas of concern for severe weather and flash flooding.
For Thursday, the Storm Prediction Center has issued an enhanced risk of severe thunderstorms across parts of the southern and central Plains and the Middle Mississippi Valley, where very large hail, significant severe wind gusts, and the potential for several tornadoes to develop will be the hazards of concern. The Weather Prediction Center has flagged a similar area as being at slight risk for excessive rainfall and flash flooding. Having been pushed south and east by a descending area of high pressure, showers and thunderstorms are expected along the Gulf and East Coasts on Friday.
A strong cold front trailing off a deep Canadian low pressure system will pass through the Northeast overnight. Ahead of the front warm temperatures and shortwave instability are expected to aid the development of showers and thunderstorms, some of which may become severe and produce damaging winds. Behind the cold front a high pressure system in southern Canada is forecast to build and spread east, transporting colder arctic air south into the northern Great Plains, Midwest, and Northeast. On Thursday and Friday, daily highs across these regions will likely drop as much as 15 to 20 degrees below normal into the 50s and 60s.
Out in the Pacific Northwest, a low pressure system moving onshore Thursday morning will bring widespread rain to the area, with mixed precipitation and even some wet snow possible in the northern Cascades. As the system moves inland the rain is forecast to expand eastward into the northern Rockies, some of which may transition into wet snow at higher elevations overnight as temperatures drop behind a cold front. The northern Cascades could see wet snow lingering into Friday morning 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 |
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These graphics update and can be clicked on to enlarge. You can see where the weather will be | |
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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 Saturday May 29 2021 – Wednesday June 02 2021
Hazards:
– Heavy rain across portions of the Central/Southern Plains, and the Middle Mississippi Valley, Sat-Tue, May 29-Jun 1.
– Flooding possible across portions of the Central/Southern Plains, and the Middle Mississippi Valley.
– Flooding occurring or imminent across portions of the Central/Southern Plains, and the Middle/Lower Mississippi Valley.
– Flooding likely across portions of the Northern Rockies.
– Much above normal temperatures across portions of California, the Great Basin, the Pacific Northwest, and the Northern Rockies , Mon-Wed, May 31-Jun 2.
– Heavy rain across portions of the Alaska Panhandle and mainland Alaska, Sat-Sun, May 29-May 30.
Detailed Summary:
In the medium-range forecast period, which includes the Memorial Day weekend, a front extends from the Mid-Atlantic southwestward to the Central Gulf Coast into the Southern Plains. An area of low pressure over the Mid-Atlantic will have stronger wind associated with the pressure gradient over the Great Lakes on Saturday, with Lake Erie having the high wind the longest. The wind speed will not meet the criteria for an area of high wind. As waves of low pressure move offshore on Saturday, the pressure gradient associated with the waves of low pressure will produce stronger wind off the Northeast and the northern Mid-Atlantic Coast on Saturday into Sunday. With the holiday weekend coming, boaters are encouraged to check with the local forecast office for any marine advisories.
A wave of low pressure along the tail end of the front mentioned above will move eastward from the Central High Plains over the Central/Southern Plains on Monday into Wednesday. The system will produce an area of heavy rain is depicted over parts of the Central/Southern Plains on Saturday through Tuesday. There is uncertainty if the heavy rain will continue over parts of the Southern Plains on Wednesday. As a result, the heavy rain area was not continued into Wednesday. However, there may be changes in the models with the placement of heavy rain over the region on Wednesday, which will be monitored to see if a change will be needed. Furthermore, the GFS is producing heavy rain over the Northeast on Wednesday. In contrast, the ECMWF model has less rain over the Northeast without the feature producing heavy rain over the Northeast. The GFS was dismissed in this case.
Upper-level ridging will develop over the Pacific Northwest into California on Sunday into Wednesday. The upper-level ridging will allow temperatures to get into the upper 80s to the middle 90s over the Northwest and the 90s into the 100s over parts of California. With this in mind, an area of much above normal temperatures is directed over Monday into Wednesday.
Furthermore, high pressure over the Eastern Pacific and a heat trough over California will produce strong winds offshore and near the coast. Still, at this time, the wind speed is below the criteria for an area of high winds. However, the situation will need to have an eye kept on the wind to see if the wind will meet the criteria later. With the holiday weekend coming, boaters are encouraged to check with the local forecast office for any marine advisories.
For Alaska, an area of low pressure along the Aleutians will move into the Gulf of Alaska by Sunday. Moisture associated with the low will stream into the coastal regions producing heavy rain from parts of the Kenai Peninsula eastward to the Inside Passage on Saturday and Sunday. At this time, the precipitation seems to be rain, but some of the higher peaks will still get snow.
(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 (or maps) weekly (or more often when the situation is changing rapidly) 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.
More information can be found here.
May Drought Outlook.
Seasonal Outlook Issued May 20, 2021
Here is the short version of the discussion that was released with the new forecast.
Latest Seasonal Assessment – Drought improved across parts of Texas, northeastern Colorado, central Wyoming and the Northeast in the past month due to heavy rainfall, while drought developed or intensified in many parts of California, the Pacific Northwest, Northern Intermountain West, Northern Rockies, and the Carolinas due to increasing precipitation deficits. Drought persistence or development is favored for most of the West and High Plains, based on elevated probabilities of below normal precipitation and above normal temperatures for June-July-August. Drought removal or improvement is expected across east-central Texas along with most of Oklahoma due to heavy recent rainfall and additional heavy rainfall forecast for the rest of May.Lack of a rainfall signal from monthly and seasonal precipitation outlooks supports drought persistence across the Midwest. The Great Plains and Corn Belt will be closely monitored in the monthly drought outlooks through the summer. The wet monthly and seasonal outlooks along with the onset of the convective season strongly support removal across the small drought areas in southern Florida. The persistence forecast for the Northeast is based on a weak rainfall signal and likelihood of above normal temperatures during June-July-August along with a favorable time for soil moisture discharge.
Alaska is forecast to remain drought-free through the end of August. Drought is favored to persist across Puerto Rico during the next few months. Drought development and persistence is forecast across the leeward sides of the Hawaiian Islands.
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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. Sorry for any confusion but the NHC maps do not update during the Winter except if there is activity. We leave them in simply because if there is a storm NOAA will start to update the relevant map even though it is not normally updated during the off season. The maps are a bit small but if you click the map you can see the date and time when it was updated.
| the Central Pacific. | the Eastern Pacific | the Atlantic and the Gulf of Mexico |
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Atlantic and Gulf of Mexico
The Eastern Pacific
NA
The Central Pacific
NA
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
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And then Precipitation
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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. |
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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. |
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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
| 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. |
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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 | |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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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