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    Precipitation type - newly added

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    • JimInSanDiegoJ
      JimInSanDiego Moderator
      last edited by

      My guess is having lived in a northern part of the US in the past, we called it sleet. The difference is raindrops fall but freeze before hitting the ground. Hail bounces around up in the air adding layer and layers. Sleet is a cold weather issue and hail is a warm weather issue.


      JamesInSanDiego
      San Diego, CA USA

      1 Reply Last reply Reply Quote 4
      • Gkikas LGPZG
        Gkikas LGPZ Moderator Meteorologist @Tomber42
        last edited by

        @tomber42
        Smaller than hailstones. Less than 5 mm in diameter.

        JimInSanDiegoJ 1 Reply Last reply Reply Quote 1
        • JimInSanDiegoJ
          JimInSanDiego Moderator @Gkikas LGPZ
          last edited by JimInSanDiego

          Also, sleet tends to be softer pellets where hail is frozen rock hard.


          JamesInSanDiego
          San Diego, CA USA

          1 Reply Last reply Reply Quote 2
          • Tomber42T
            Tomber42 Moderator
            last edited by

            Ahh.. Ok, now I know.. in German. we say Graupel

            Greetings from Tomber

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            • MarienkaM
              Marienka @Tomber42
              last edited by Marienka

              Hi @Tomber42 , it's different. We don't actually have a "hail" icon nor a layer for it. Hail normally occurs in rainstorm or thunderstorm, and is the result of strong updrafts that repeatedly carry growing chunks of ice upwards into the clouds. Unlike freezing rain, graupel or ice pellets (that are softer and smaller in size), hail is hard as stones, bigger in size and causes extreme damage (dents in metal etc)... In general, hail is difficult to predict as there are quite a few ingoing influences and complicating factors that interfere with the course of the storm.

              As @JimInSanDiego correctly summed it up: Hail is a warm weather issue, while freezing rain or ice pellets (sleet) are manifestations of cold weather.

              Best wishes
              ~ Marie

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              • MarienkaM
                Marienka @Marienka
                last edited by Marienka

                Here is a quick tutorial to describe the differences between: hail, graupel (soft hail / snow pellets), ice pellets (sleet) and freezing rain. Wikipedia puts it this way:

                HAIL is a form of solid precipitation. It is distinct from ice pellets (American sleet), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. [...] Unlike other forms of water ice such as graupel, which is made of rime, and ice pellets, which are smaller and translucent, hailstones usually measure between 5 millimetres (0.2 in) and 15 centimetres (6 in) in diameter.
                In more detail: https://en.wikipedia.org/wiki/Hail

                GRAUPEL (from German language), also called SOFT HAIL or SNOW PELLETS, is precipitation that forms when supercooled water droplets are collected and freeze on falling snowflakes, forming 2–5 mm (0.08–0.20 in) balls of rime. Graupel is distinct from hail, small hail and ice pellets: the World Meteorological Organization defines small hail as snow pellets encapsulated by ice, a precipitation halfway between graupel and hail.
                In more detail: https://en.wikipedia.org/wiki/Graupel

                ICE PELLETS (American: SLEET) are rain drops that have frozen before they hit the ground. When they hit the ground, they bounce. Ice pellets are also called sleet and can be accompanied by freezing rain. In winter, precipitation usually begins falling out of a cloud as ice particles.
                In more detail: https://en.wikipedia.org/wiki/Ice_pellets

                FREEZING RAIN is the name given to rain precipitation that freezes on contact on surfaces maintained at temperature below freezing by the ambient air mass. Unlike sleet, a mixture of rain and snow, ice pellets, or hail, freezing rain is made entirely of liquid droplets. The raindrops become supercooled while passing through a sub-freezing layer of air hundreds of meters above the ground, and then freeze upon impact with any surface they encounter...
                In more detail: https://en.wikipedia.org/wiki/Freezing_rain

                Best wishes
                ~ Marie

                1 Reply Last reply Reply Quote 4
                • MarienkaM
                  Marienka
                  last edited by

                  Here I found some interesting link with illustrative pictures:
                  Will it [freezing] RAIN, SLEET or SNOW?

                  http://www.weather.gov/source/zhu/ZHU_Training_Page/winter_stuff/winter_wx/winter_wx.html

                  Best wishes
                  ~ Marie

                  1 Reply Last reply Reply Quote 5
                  • A
                    artmunich
                    last edited by

                    And what is wet snow? What's the difference between wet snow and rain with snow?

                    Gkikas LGPZG 1 Reply Last reply Reply Quote 0
                    • Gkikas LGPZG
                      Gkikas LGPZ Moderator Meteorologist @artmunich
                      last edited by

                      @artmunich
                      https://en.wikipedia.org/wiki/Rain_and_snow_mixed

                      http://theweatherprediction.com/habyhints2/650/

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                      • eshtewiE
                        eshtewi
                        last edited by

                        0_1538980019654_134 (2).jpg

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                        • A
                          asakalli
                          last edited by asakalli

                          Dear All, Dear @Marienka
                          may I ask the algorithm behind this new overlay? I'd like to use the same algorithm to calculate the type of precipitation in my country. I'm running WRF model for my research activities at the Iskenderun Technical University. Thank you very much for your response in advance.
                          Happy new year to all.

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                          • ivoI ivo referenced this topic on
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                            esheesle @Marienka
                            last edited by

                            @Marienka How often is this overlay updated? It appears to be only hourly maybe?

                            SutyS 1 Reply Last reply Reply Quote 0
                            • SutyS
                              Suty Administrator @esheesle
                              last edited by

                              @esheesle It depends on the model, you check, and the plan you have. Premium is usually updated 4 times per day and you can check data with 1h step. Free offers 2 updates and 3h steps.
                              5970a7b5-ca7f-44bc-b214-8f4ca4550f80-image.png

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                              • briannaessB
                                briannaess | Premium
                                last edited by

                                In general, I like having this overlay, though I wish it were combined with Radar. However, my primary complaint is that "Rain" is colored as light blue, which is often associated as snow on many other precipitation type maps offered by other services. I would suggest changing the color of Rain to green to be consistent with other maps to avoid confusion.

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                                • S
                                  stpdgld
                                  last edited by stpdgld

                                  The precipitation type map shows predominantly dark gray and white. Those colors are not in the legend, so may I ask what those colors represent? I assume the dark gray represents no precipitation, but when I look up the current weather in the white areas, no precipitation exists there as well. Freezing point doesn't seem to be a factor either. Thanks! Screenshot 2025-01-11 120440.png

                                  idefix37I 1 Reply Last reply Reply Quote 0
                                  • idefix37I
                                    idefix37 Sailor Moderator @stpdgld
                                    last edited by idefix37

                                    @stpdgld
                                    White is in the legend even it is a sort of light gray to make the word “snow” in white letters readable.
                                    Grey is where there is no precipitation. This is quite obvious.

                                    36BEC7E6-E7DC-4F2C-A0BC-F56F9A449258.jpeg

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                                    • S
                                      stpdgld @idefix37
                                      last edited by

                                      @idefix37 Okay, thanks. I had a feeling the color shade was wrong in the legend, but when I looked up current weather in the white areas, it was not currently snowing in those locations.

                                      idefix37I 1 Reply Last reply Reply Quote 0
                                      • idefix37I
                                        idefix37 Sailor Moderator @stpdgld
                                        last edited by idefix37

                                        @stpdgld
                                        What model did you use for Precipitation types?
                                        Then are you talking about your own observations or the model snow forecast?

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                                        • S
                                          stpdgld @idefix37
                                          last edited by

                                          @idefix37 ECMWF and I compared it against a report from the Aviation Weather Center.

                                          idefix37I 1 Reply Last reply Reply Quote 0
                                          • idefix37I
                                            idefix37 Sailor Moderator @stpdgld
                                            last edited by idefix37

                                            @stpdgld
                                            If you compare Precipitation type layer to observations, there is some chance that ECMWF forecast does not match these observations.
                                            A prediction is not a report.
                                            But this layer and the local forecast by ECMWF are consistent.

                                            1A3D721D-9C29-4AE6-8D24-3B2FD162355E.jpeg

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