Stormy Weather II

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  • Serial_Apologist
    Full Member
    • Dec 2010
    • 37619

    Originally posted by Lat-Literal View Post
    A lull around midday with little ice on the road. Just snow on the gardens and some pavements. Now it is snowing again - heavily. I thought this wasn't supposed to be happening?
    Those pesky convergence zones that materialise outy of nowhere! All it takes is for slipstreams within an otherwise homogeneous airstream to converge, often as result of pressure systems on either side being re-positioned in relation to each other, and it's like lorries converging at a point where three lanes suddenly become two and there's nowhere for the air to go but up! Something very similar happened on Friday, but with warm humid air advancing northwards across Sussex and Surrey coming up against a tightening pressure grade further north bringing in cold east winds from the N Sea ahead of the current cold spell. Introduced cold air at altitude is a major generator of showers, and in that instance at about 5 pm resulted in a nice little thunderstorm, with all of four flashes of lightning in the Tottenham area. It really should have been possible to forecast this particular area of snow - I think something may have been mentioned on the lunchtime forecast, but at that moment a low-flying aircraft came across!

    Comment

    • BBMmk2
      Late Member
      • Nov 2010
      • 20908

      !C here today. Had quite a bit of snow falling but none settled yesterday. We are having a flurry right now.
      Don’t cry for me
      I go where music was born

      J S Bach 1685-1750

      Comment

      • Lat-Literal
        Guest
        • Aug 2015
        • 6983

        Originally posted by Serial_Apologist View Post
        Those pesky convergence zones that materialise outy of nowhere! All it takes is for slipstreams within an otherwise homogeneous airstream to converge, often as result of pressure systems on either side being re-positioned in relation to each other, and it's like lorries converging at a point where three lanes suddenly become two and there's nowhere for the air to go but up! Something very similar happened on Friday, but with warm humid air advancing northwards across Sussex and Surrey coming up against a tightening pressure grade further north bringing in cold east winds from the N Sea ahead of the current cold spell. Introduced cold air at altitude is a major generator of showers, and in that instance at about 5 pm resulted in a nice little thunderstorm, with all of four flashes of lightning in the Tottenham area. It really should have been possible to forecast this particular area of snow - I think something may have been mentioned on the lunchtime forecast, but at that moment a low-flying aircraft came across!
        Thank you.

        Will it all melt by lunchtime?

        It doesn't look like it will do.

        Comment

        • DracoM
          Host
          • Mar 2007
          • 12962

          Wonderful day oop 'ere - brilliant sun, blustery easterly, cold, but manageable. Could Spring be far behind?

          Comment

          • Serial_Apologist
            Full Member
            • Dec 2010
            • 37619

            Originally posted by Lat-Literal View Post
            Thank you.

            Will it all melt by lunchtime?

            It doesn't look like it will do.
            The strength of the late March sun will quickly melt snow cover on south-facing slopes, but with shade temperatures probably not exceeding + 2 C on northern slops such as this one where I live, I would expect snow to survive in shaded hollows for at least another day. It should all be gone by Thursday here in the SE, but where those deep drifts are in Wales and the SW, that's another matter!

            Comment

            • Serial_Apologist
              Full Member
              • Dec 2010
              • 37619

              Originally posted by DracoM View Post
              Wonderful day oop 'ere - brilliant sun, blustery easterly, cold, but manageable. Could Spring be far behind?
              Temps should be back to the seasonal norms everywhere by Thursday - just in good time for a rainy weekend!

              Comment

              • BBMmk2
                Late Member
                • Nov 2010
                • 20908

                How likely is it for another blast from the beast from the East, say around my area? SA?
                Don’t cry for me
                I go where music was born

                J S Bach 1685-1750

                Comment

                • Serial_Apologist
                  Full Member
                  • Dec 2010
                  • 37619

                  Originally posted by Brassbandmaestro View Post
                  How likely is it for another blast from the beast from the East, say around my area? SA?
                  Sorry - too soon to say, but not in the forseeable!

                  Comment

                  • cloughie
                    Full Member
                    • Dec 2011
                    • 22115

                    Originally posted by Serial_Apologist View Post
                    Sorry - too soon to say, but not in the forseeable!
                    A lovely, wrap up well, sunny day here, 8 degrees!
                    Last edited by cloughie; 20-03-18, 15:58.

                    Comment

                    • Serial_Apologist
                      Full Member
                      • Dec 2010
                      • 37619

                      Last of the snow now gone here; wind's dropped following this morning's light rain showers along a weak cold front moving south; but it still feels cold! The latest suggests a possible cold Easter weekend, with sleet, hail, snow and thunder showers brought down on a strong northerly behind a deepish low in the N Sea, this time: comments to the effect of white Easters being more common than ditto Christmases - which is apparently true!

                      Comment

                      • BBMmk2
                        Late Member
                        • Nov 2010
                        • 20908

                        Originally posted by Serial_Apologist View Post
                        Sorry - too soon to say, but not in the forseeable!
                        It'll be damn cold though!
                        Don’t cry for me
                        I go where music was born

                        J S Bach 1685-1750

                        Comment

                        • ferneyhoughgeliebte
                          Gone fishin'
                          • Sep 2011
                          • 30163

                          Originally posted by cloughie View Post
                          A lovely, wrap up well, sunny day here, 8%!
                          Ditto this afternoon in this bit of the Pennines - in fact, I "wrapped up" a little too "well" and got a bit too warm for comfort!
                          [FONT=Comic Sans MS][I][B]Numquam Satis![/B][/I][/FONT]

                          Comment

                          • Serial_Apologist
                            Full Member
                            • Dec 2010
                            • 37619

                            Originally posted by Brassbandmaestro View Post
                            It'll be damn cold though!
                            Well, temperatures tend to rapidly yo-yo in that type of weather set-up at this time of year, through to May: Sunny periods between showers can bring temperatures well up in the sunshine, but then they dip when a large shower comes along and emits large amounts of freezing cold air from on high. Customers sat outside pubs and restaurants enjoying the spring sunshine are suddenly taken by surprise! It's one of those seeming paradoxes that ground conditions too cold in January to lead to convection and showers forming can be warm enough to spark off cloud growth resulting in snow showers in spring. This is why in a January northerly the forecasters always predict showers around the coasts, these having formed over the relatively warm seas, while inland will have clear, cloudless sunshine - asnd incidentally some of the best visibilities ever on offer. The air above the cold ground is too cold and therefore lacking in the necessary energy to be able to ascend. On the other hand, I've known a couple of inches of snow falling in the space of half an hour from one of those April snow showers to then completely melt within another hour.

                            Comment

                            • BBMmk2
                              Late Member
                              • Nov 2010
                              • 20908

                              Originally posted by Serial_Apologist View Post
                              Well, temperatures tend to rapidly yo-yo in that type of weather set-up at this time of year, through to May: Sunny periods between showers can bring temperatures well up in the sunshine, but then they dip when a large shower comes along and emits large amounts of freezing cold air from on high. Customers sat outside pubs and restaurants enjoying the spring sunshine are suddenly taken by surprise! It's one of those seeming paradoxes that ground conditions too cold in January to lead to convection and showers forming can be warm enough to spark off cloud growth resulting in snow showers in spring. This is why in a January northerly the forecasters always predict showers around the coasts, these having formed over the relatively warm seas, while inland will have clear, cloudless sunshine - asnd incidentally some of the best visibilities ever on offer. The air above the cold ground is too cold and therefore lacking in the necessary energy to be able to ascend. On the other hand, I've known a couple of inches of snow falling in the space of half an hour from one of those April snow showers to then completely melt within another hour.
                              I remember just last year, in April, when temps were around 20C !

                              Sunny today!
                              Don’t cry for me
                              I go where music was born

                              J S Bach 1685-1750

                              Comment

                              • greenilex
                                Full Member
                                • Nov 2010
                                • 1626

                                Southampton Water just perfect this morning when the dog and I took the ferry across to Hythe: sunshine, gentle breeze, friendly fellow passengers and the prospect of a picnic on the Holbury road.

                                Slightly choppier on the way back, and we were pleasantly worn out.

                                Comment

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