Written by Sig Silber
HEADLINES (Updated 10:38 pm EDT) –
“– Areas of heavy rainfall and some flash flooding possible from the Central Plains and Middle Mississippi Valley east to the Mid-Atlantic
– Extreme heat, dry weather and locally elevated fire danger to persist out West
– Tropical Storm Isaias may bring impactful weather to the Southeast coast this weekend”
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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CONUS Focal Points
Short Range Focal Points
Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 403 PM EDT Thu Jul 30 2020
Valid 00Z Fri Jul 31 2020 – 00Z Sun Aug 02 2020
…Areas of heavy rainfall and some flash flooding possible from the Central Plains and Middle Mississippi Valley east to the Mid-Atlantic…
…Extreme heat, dry weather and locally elevated fire danger to persist out West…
…Tropical Storm Isaias may bring impactful weather to the Southeast coast this weekend…
The wettest conditions across the Lower 48 look to occur from the Southern Plains and Middle Mississippi Valley to the Mid-Atlantic due to waves of low pressure developing along an elongated frontal boundary. A slight risk for excessive rainfall and a swath of Flash Flood Watches are in place from central Kansas to the southern and central Appalachians this evening. There is also a slight risk for severe weather across the Southern Plains, through central Arkansas, and into western Tennessee. By Friday, the front across the east-central U.S. will slightly dip south into the Mid-South forcing heavy showers and storms to develop over the Lower Mississippi and Tennessee Valleys. As a result, a slight risk for flash flooding is effect in these regions as well as the central Appalachians. While a cold front swings through the South Central U.S. on Saturday, an upper level trough over the Mississippi Valley will continue to generate low pressure over the Ohio Valley, thus keeping the threat for flash flooding in the forecast across the region the first half of the weekend.
While much of the Plains witness cooler than normal temperatures heading into the weekend, extreme heat and locally elevated fire danger engulfs much of the Pacific Northwest, Great Basin and the Southwest U.S. as a strong ridge of high pressure develops overhead. More record high temperatures are expected in parts of these regions on Friday as temperatures approach and exceed the century mark for many interior deserts. In fact, portions of the Desert Southwest are likely to see temperatures range between 110 to 120 degrees Friday afternoon. The abnormally hot weather combined with very dry air and locally gusty winds will enhance the fire danger as a result, with the biggest concerns across the Northwest given the potential for lightning strikes associated with some dry thunderstorm activity. The Storm Prediction Center features elevated risks for fire weather in the Northwest and central Great Basin this evening and on Friday.
Tropical Storm Isaias (pronounced ees-ah-EE-ahs) is currently just off the northern coast of Hispaniola and tracking west-northwest this afternoon. Isaias will pass south of the Turks and Caicos tonight and track along the southern periphery of the Bahamas on Friday. The latest forecast calls for the storm to approach the eastern coast of Florida on Saturday and remain very close to the Southeast coast this weekend. There is the potential for heavy rain, strong winds, and significant coastal impacts but the storm’s future track and intensity are still unclear. Please consult the latest National Hurricane Center public advisories for more information.
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
Hazards:
– Heavy rain across portions of northern New York, as well as from eastern Florida northward through the Carolinas and all of the Mid-Atlantic, Sun-Mon, Aug 2-Aug 3.
– Heavy rain along the Mid-Atlantic coast into central and southern New England as well as coastal Maine, Tue-Wed, Aug 4-Aug 5.
– Flooding possible across portions of northern and central Plains.
– Flooding occurring or imminent across portions of the northern Plains.
– High winds across portions of eastern Florida, Sun, Aug 2.
– High winds across much of the Mid-Atlantic and southern New England coastal areas, Mon-Tue, Aug 3-Aug 4.
– Significant waves possible near the North Carolina coast, Mon, Aug. 3.
– Heavy rain across portions of the Alaska Panhandle and southern Alaska, Sun-Wed, Aug 2-Aug 5.Detailed Summary:
During the medium range period, attentions will surely be drawn to the East Coast where tropical cyclone Isaias could potentially bring significant impacts from Florida all way up to New England. The initial synoptic setup will be an amplifying omega block pattern over western Canada in conjunction with a positively-tilted trough lingering across the eastern-central U.S. This pattern will likely bring Isaias close to the East Coast early next week as the tropical cyclone tracks around the southwestern and western periphery of the Bermuda High. It appears that all of the East Coast will be under a threat of heavy rain associated with Isaias starting from Florida during the weekend and then gradually working its way up the East Coast Monday and Tuesday. Based on the latest forecast track of Isaias from the National Hurricane Center (NHC), it appears that much of the East Seaboard, except perhaps the Georgia coast, will have a good chance of experiencing high winds as Isaias nears. Significant waves are also possible on Monday near the North Carolina coast as Isaias could move across at a close distance. High seas may expand in coverage along the East Coast should Isaias intensify further as a hurricane. Please consult the NHC for the latest updates on Isaias. Farther inland, a wave of low pressure forming along a frontal boundary ahead of the lingering trough over the eastern-central U.S. should lead to heavy rain over northern New York Sunday into Monday, before slowly edging further to the east.
Meanwhile, an upper-level ridge will remain a dominant feature over the western U.S. Temperatures should be about 5 to 10 degrees above normal across much of the interior western U.S. before an upper trough brings cooler air into the Pacific Northwest and the northern Rockies by early next week. High temperatures are expected to top 115 degrees for the hottest locations in Desert Southwest Sunday and Monday before moderating very gradually toward the middle of next week. Over the northern and central Plains, much cooler than normal temperatures will remain in place behind the aforementioned slow-moving trough.
Over Alaska, the pattern appears to get more active during the medium-range period as a couple of significant occluded cyclones are forecast to impact the southern periphery of the state. This appears to be more of a prolonged rain event than heavy rain falling in a short time-frame. A heavy rain area is indicated on the map from the southern coastal sections of Alaska down along the Panhandle from Saturday into Wednesday. There could be another occluded cyclone that may bring heavy rain into the Panhandle by next Thursday but uncertainty is currently too high to specify a heavy rain 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
We will resume more detailed coverage when the summer is over.
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Tropical Events
This is now beyond the time of the year we pay special attention to Tropical Events other than the Western Pacific.
So 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.
the Central Pacific. | the Eastern Pacific | the Atlantic and the Gulf of Mexico |
Updates on individual named storms can be obtained here.
And the Western Pacific
Week 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
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. |
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 |
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 |