August 20, 2022: 48-Hour Weather Report and Intermediate-Term Outlooks; Tropical

Here is what we are paying attention to this evening and the next 48 hours from this evening’s NWS Forecast.

...Significant heavy rainfall event may lead to major flash flood impacts
in the Southwest...

...More heat expected across interior California and the Pacific
Northwest...

...Thunderstorms could become severe over the Midwest today and
thunderstorms and possible flooding rains will spread across the
South/Southeast and then up the Mid-Atlantic by the weekend...

Continuation of the NWS Short Range Forecast (It is updated twice a day and these updates can be found here.

Much of southern Arizona and New Mexico could have prolific rainfall and
widespread significant flash flooding conditions into the weekend as a
mid-level low and anomalously high moisture associated with a remnant
tropical wave help to enhance storm development associated with an already
very active monsoon season. WPC has a Moderate Risk for excessive rainfall
covering southeast Arizona and southwest/central New Mexico, Slight Risk
spanning from western Arizona to the Texas panhandle and Marginally
encompassing those areas and into the Four Corners/Rockies region. Areal
average rainfall totals of 2-3 inches, with locally higher amounts
approaching 5-7 inches, may lead to numerous instances of flash flooding.
Urban locations in addition to areas of complex terrain, slot canyons,
arroyos, and burn scars are especially vulnerable for flash flooding and
can quickly turn into very dangerous situations.

The focus of the heavy rainfall is expected to shift eastward into the
Southern Plains and persist in proximity to a wavy, stationary front
stretching from the Southeast into the Southern Plains. Several inches of
rain are forecast along a nearly west-east axis from the Texas Panhandle
to the Gulf states, with the heaviest amounts focusing over northeast
Texas, southern Oklahoma, southern Arkansas and northern Louisiana. Much
of this part of the country has had drought conditions, but multiple days
of moderate to excessive rainfall may quickly lead to areas of flooding.
WPC parts of Southern Plains covered by a Slight Risk for Sunday into
Monday. Further north, widespread showers and thunderstorms will continue
along a frontal system moving from the Northern Plains into the Midwest
into the weekend. Instability associated with an upper low rotating across
the northern Plains toward the Midwest could trigger severe thunderstorms
later today into tonight from Iowa into northern Missouri and western
Illinois.  This system will likely trigger additional strong to severe
thunderstorms as it approaches the Great Lakes later Saturday into Sunday
morning.

The heatwave will persist over California and the Pacific Northwest.
Numerous heat-related advisories are in place as temperatures are forecast
to reach into the upper 90s to low 100s today for portions of the interior
Pacific Northwest and northern Great Basin. Some moderating of the daily
temperatures will occur by Saturday with the approaching upper-level, with
a few degrees cool down expected. The central valleys of California, the
heat is forecast to peak on Saturday where afternoon temperatures are
expected to reach into the low to mid-100s. In contrast, much of the
Southwest, Great Basin and Southern Rockies will be well below normal due
to the extensive cloud cover and prolonged rainfall. Daily maximum
temperatures will stay in the 70s to lower 80s. Below normal highs are
also forecast for the Southeast (low to mid-80s) and for the Northern
Plains (low to mid-70s) under the upper low, with temperatures increasing
a few degrees closer to normal Saturday. Hotter temperatures in the upper
80s to around 90 degrees will return to the Mid-Atlantic and New England
with otherwise tranquil conditions expected into the weekend.

Maps that relate the forecast to geography can be found by clicking  Here for Day 1 and Here for Day 2.

Here is a 60-hour animated forecast map that shows how the short-term forecast is expected to play out.

If it needs to be updated click here.

HAZARDS OUTLOOKS

Click here for the latest complete Day 3 -7 Hazards forecast which updates only on weekdays.  Once a week probably Monday or Tuesday I will update the images. I provided the link for readers to get daily updates on weekdays. Use your own judgment to decide if you need to update these images.

Worldwide Tropical Forecast

(This graphic updates on Tuesdays) If it has not been updated, you can get the update by clicking here

Detailed Maps and Reports for the Western Atlantic and the Pacific Oceans

Below are three maps that summarize the situation for the Atlantic, Eastern and Central Pacific. Additional information can be accessed by clicking HERE

First the Atlantic

Click to view the forecast map and have access to additional information https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=5

Then Eastern Pacific

Click to view the forecast map and have access to additional information https://www.nhc.noaa.gov/gtwo.php?basin=epac&fdays=5

Then Central Pacific

Click to view the forecast map and have access to additional information https://www.nhc.noaa.gov/gtwo.php?basin=cpac&fdays=5

And the Western Pacific

Click to view the forecast map and have access to additional information https://www.metoc.navy.mil/jtwc/jtwc.html

Some Intermediate-Term Outlooks

Links to “Outlook” maps and discussions for three time periods. Days 6 – 10, Days 8 – 14, and Weeks 3 and 4.  An outlook differs from a forecast based on how NOAA uses these terms in that an “outlook” presents information from deviation from normal and the likelihood of these deviations.

You have to click on the links because they do not update automatically and I do not want to have stale images in the article. But it is not difficult to click on a link and you get a large image plus a discussion. On Fridays in a separate article, we will show the images and provide a link in this article that article. But remember what you will see is the images as of Friday. But here you can get the current images simply by clicking on them. Then hit the return arrow at the upper left of your screen to return to the article. You will not find this information easily anywhere else.

The following is provided to help the reader relate the maps and the discussion that comes with the maps to how NWS will describe an area of the U.S.

https://i0.wp.com/www.wpc.ncep.noaa.gov/bndrys1.gif?w=1100&ssl=1

Days 6 – 10 Days 8 – 14 Weeks 3 and 4
https://www.cpc.ncep.noaa.gov/products/predictions/610day/ https://www.cpc.ncep.noaa.gov/products/predictions/814day/ https://www.cpc.ncep.noaa.gov/products/predictions/WK34/

Right now you can find these maps here (We show them every Friday there but you can click above and find them).

World Forecast for Day 6 (Currently Set for Day 6 but the reader can change that)

World Weather Forecast produced by the Australian Bureau of Meteorology. Unfortunately, I do not know how to extract the control panel and embed it into my report so that you could use the tool within my report. But if you visit it Click  Here and you will be able to use the tool to view temperature or many other things for THE WORLD. It can forecast out for a week. Pretty cool. Return to this report by using the “Back Arrow” usually found top left corner of your screen to the left of the URL Box. It may require hitting it a few times depending on how deep you are into the BOM tool. Below are the current worldwide precipitation and air pressure forecasts for six days out. They will not auto-update and right now are current for Day 6. If you want the forecast for a different day Click Here  I will try to update this map each day but you have the link so you can access the dashboard and get a wide variety of forecasts.

I mostly rely on the reader to interpret world maps. For this map, areas of expected precipitation for the date and time shown are clearly shown.

The number of High-Pressure systems shown is called the Wave Number. Maybe I will discuss WN someday. But it shows how many Rossby Waves there are around the World. Sometimes they are hard to count. Counting Low-Pressure systems should provide the same WN.  Rossby Waves are the way the temperature distribution of the Planet remains in balance. It is basically the science of fluid dynamics.  It can be very helpful in predicting the movement of weather patterns.

Month to Date Information

Month to date Temperature can be found at https://hprcc.unl.edu/products/maps/acis/MonthTDeptUS.png

Month to date Precipitation can be found at  https://hprcc.unl.edu/products/maps/acis/MonthPNormUS.png

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