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  1. 22 points
  2. 20 points
  3. 20 points
    My thoughts.... A high impact wintry event will move through the region. A strong low pressure system will track northeast from the Southern Plains into the midwest. With the high offshore, warm air advection will increase and correspond with a warm front pushing northward. Isentropic lift will combine with increased mid level vertical velocities and frontogenesis forcing leading to the development of precipitation late Friday night and Saturday which is highly probable to become moderate or heavy at times. Wind gusts of 20 mph are possible as well in this timeframe. The precipitation should start everywhere as snow but the warm air advection will be potent (strong LLJ) with the high not in an ideal place to keep cold air around for an extended period. The snow should quickly change to rain Saturday morning across Delmarva and coastal New Jersey south of Atlantic City. Further north the snow will last a few hours longer in the Philadelphia and central New Jersey regions changing over by noon. In Northern New Jersey, the Lehigh Valley and Southern Poconos cold air is likely to hang on throughout most of the day before seeing a changeover to rain. A period of sleet and freezing rain is also probable at many locations in the transition as the mid-levels warm faster than the surface. For some of the valleys north and west, it may be more of a challenge to scour out the low level cold resulting in an extended period of ice. Models are notorious for getting rid of low level cold too quick. One thing that could allow the cold to hang on longer would be the formation of a secondary low off the NJ coastline, which is a possibility shown on some ensemble members. First guess snow totals with a few locations listed for each range. Will likely change based on track and intensity of system in the coming days. Ratios may start out in the 10-15:1 as snow growth looks favorable in the -10 to 20C layer along with the favorable lift described above. 4-6 for Mount Pocono, Wantage, Reading, Allentown and Somerville. 2-4 for Wilmington, Philadelphia, Mount Holly and New Brunswick 1-2 for Dover, Millville northeast into the Pine Barrens Less than an inch is currently expected for Georgetown and Cape May. Temperatures will continue to rise Saturday night in the warm sector. However, the forcing which results in widespread rain and snow Saturday takes a break Saturday night resulting in a dry slot or just some scattered rain showers. An 8-9 Standard deviation spread with the ensembles for temperatures is present in this timeframe, really high uncertainty.
  4. 18 points
  5. 17 points
    LOVE sticky snow, best snow for photos!
  6. 16 points
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  8. 16 points
  9. 15 points
    If your house is lit up let's see it. This is my house this year. I add new things each year.
  10. 14 points
    From Mrs WMW, on the farm in East Fallowfield
  11. 14 points
    Had a Cooper's hawk stop by in the middle of the storm. 4.25" is the final it seems here
  12. 13 points
    So times are a changing. We currently right now have a very zonal flow (flow is west to east) You can see that from this map. When the flow is zonal like this it is very easy to see why we aren't cold. The air is coming straight from the Pacific. Note, that even though we do have a -nao signature, it's displaced to far north and also the air in Canada, while cold is of Pacific origin. Also note, do to the zonal flow, all the cold air is bottled up north of the border. You need amplification in the pattern or a further south -nao to force the cold south. This zonal flow is also connected well with phase 4 MJO which shows a very flat flow/ridging. (Above) current green anomalies showing the tropical forcing pushing out of the IO region and towards Indonesia This zonal flow though will not last and we can trace the pattern shift back to Asia with a strong closed low that I have marked X. Note the looping feature, the wave break from this disturbance gets the ball rolling in the Pacific with pumping a ridge out ahead of it. The ridging caused from the wavebreak becomes a very stable feature as each each low on the wave train in the pacific only reinforces it. As we get further down the road in the 10-15 day period, the MJO also starts supporting a west coast ridge/east coast trough. While the robust convection currently wanes, the area of forcing still continues to move towards the dateline and then the maritime continent and Africa. The tropical forcing of phases 7->2 take the rest of Dec and into early Jan for it to run it's course. So that is also supporting a persistent trough signal in the east for the rest of DEC into the first week of January. Now a result of a wavebreak in Asia pumping up the heights into Alaska and the West Coast and then later on the MJO signal backing that up, we get this look. This is what we call meridonal flow. Basically flow that is more north to south representing an amplified pattern. Unlike the zonal flow you can clearly see where the air is coming straight from. The amplitude allows for the cold air to come south. This would set up below normal temperatures and would increase snow/ice chances. Below is the day 10 ensemble forecast off the EPS. This h5 map is basically the holy grail for any fan of cold and wintry weather. You have a +pna to give you the amplitude in the pattern to allow shortwaves to strengthen and to send the cold air south. The -nao slows the pattern in the Atlantic down blocking in areas of low pressure and high pressure. You also have a -AO which displaces cold anomalies that are usually found at the pole south into the mid latitudes. This is another source for bringing cold air south. Furthermore, due to the h5 configuration of an Aleutian low and Siberian high, this is a classic wave 1 disruption in the Stratosphere which we can see below. Wave 1 hits on the Stratospheric polar vortex are a good signal that cold air is on the move south. With that being said, the MJO forcing progression into cold phases and the continued hits on the Stratospheric PV Colder than normal December is gaining some ground. If these Ensemble outputs are correct snow chances are going to go up.
  13. 13 points
  14. 13 points
    400 pm 6.5 inches!!! Four inches mainly in the last two hours.
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  16. 12 points
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  18. 12 points
    A few pics from my drive home today, minus the deck pic.
  19. 12 points
    farmland a stones throw away from the hood in Lower Makefield, man it's was cold standing next to an open field with wind howling
  20. 12 points
    Despite the fact that we didn't get the projected totals, this was a hell of a storm and was well worth the hype. It's not very often you get 2-3" of sleet. A foot plus in LV and berks counties. 2ft plus in the poconos and almost a third of an inch of freezing rain in nj and delaware in mid march
  21. 12 points
    fresh coating on baxter with last squall
  22. 12 points
    Sunrise this morning in East Fallowfield
  23. 12 points
    I believe in always giving credit where credit is due and I gotta give alot of credit to Tony on this one, he made an excellent call on the backing NW, well done. I was 100% wrong on thinking this was going to stop at i95. Even though I didn't get much snow the fun of just tracking and sharing ideas on this storm makes it all wroth while. I'm glad everyone to the south and east got hit good today, it's been a rough season so far for those areas.
  24. 12 points
    I am eating a cannoli and watching it snow. For the first time in 35 years I can sit back and enjoy it.
  25. 12 points
    Just my 2 cents but... I don't see much if any sleet or mixed pcpn up to phl this run. With the upper low tracking ene rather than up the coast, it will be hard to get enough warm air this far north to get mix. Using the ECMWF, the zero line at h8 is S of State of Delaware. Even though some warmer air may be up to 800 or even 750 mb, I dont see it making it up here. I also looked at the GFS and it seems too cold for any mix based on track and soundings. GFS soundings for Sat night imply embedded convection with some instability around 600 mb and above. Psbl thundersnow if it forms, I do see a difference between the 72hr GFS and ECMWF and this has to do with the circulation around the closed upper low to the south. Visually the GFS seems a bit more expansive than the ECMWF. In my mind this means the GFS also means a more northern extent to the very heavy snow and if it forms, any thundersnow. Something to watch when we get closer is for an inverted trough to form off the east coast that will suggest the track of the sfc low and how far north the core of the system can get. I know this is old style fcstg, but if the trough does not get up to the Jersey coastal waters, then all pcpn should be snow since the warmer air will be staying to the south.
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