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OKpowdah

Moderator Meteorologist
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Everything posted by OKpowdah

  1. Using October northern hemisphere 500mb heights, equatorial sea surface temperatures, and the QBO, and projecting the October 2013 pattern on all previous years, here are the "weights" I get for each year: ftp://ftp.cdc.noaa.gov/Public/incoming/timeseries/octanalog9.txt Check comparison of the October 2013 pattern to the analog mean pattern: And then moving the analog means forward in time: NOVEMBER DECEMBER JANUARY Notice that the November pattern also aligns reasonably with what we are seeing unfold: the developing +NAO/-PNA pattern and ridging in the SE US. Based on the analog composite, December is a warm pattern everywhere east of the Rockies. The January pattern has the potential to be cold and stormy for the Northeast US. The biggest signal is in that central to eastern Pacific trough, anchoring ridging over the western US. There's also disconnect in the AO and NAO. The continued west-based +NAO while coupled with above normal heights on the other side of the arctic can produce some shots of arctic air into the Northeast. Just wanted to share a quit and dirty analog run. Happy switch back to standard time everyone!
  2. While sensible weather in the US definitely didn't work out for the October analogs, the 500mb pattern features verified: Ridging over the north Pacific, lower heights across eastern Canada, ridging over the northeast Atlantic, ridging over western Asia -- overall mid latitude ridging and a positive index annular mode.
  3. OKpowdah

    Weekend winter storm

    We've all seen the multiple 1040mb+ arctic highs that are projected to roll down the lee of the Rockies. There's a lot of uncertainty in the timing of the cold front, along with amount of moisture that gets lifted behind front. The NAM is printing out a very icy scenario for parts of Oklahoma (albeit it is the NAM at 78-84hrs). The Euro also produces wintry precip. Whereas the GFS keeps precip ahead of the front. I don't have time to really write up something, but I thought we should consolidate discussion in this thread, for the upcoming wintry period across the region.
  4. OKpowdah

    Weekend winter storm

    There's light snow being reported in the TX panhandle at 26/23, but with conditions like 32/20 in western OK, I'm guessing nothing is reaching the ground there right now.
  5. OKpowdah

    Weekend winter storm

    Dendritic growth zone is right around 500mb, and there's a nice deformation zone at 500mb aligned from C KS down into NE OK. There's a band of stronger lift on the warm side, and you can also see the RH gradient tightening toward the axis of dilatation. Need to overcome dry air at the sfc, but once that happens, there's probably a good burst of snow in the late morning across C OK.
  6. OKpowdah

    Weekend winter storm

    Some of the heaviest snow/sleet tomorrow in Oklahoma is projected to coincide with a 1040mb high overhead.
  7. There could be some improvement of understanding, if we dropped the one dimensional indices and actually looked at the pattern. My guess is some people would be helpless without their three letter acronyms
  8. So far, the analogs for November have nailed the major teleconnections: North Pacific ridging, lending to a -PNA, and +NAO --> east based -NAO, and the overall positive annular mode. However, the details in the longitudes of the three ridge axes have made a difference.
  9. Lock it up. For those of you with #QPFfetish
  10. OKpowdah

    November weather dicsussion

    Pretty classic inverted trough on the 00z CMC for Sunday. Very different from GFS or Euro
  11. GFS, Euro, CMC all toying around with some wintry weather for the central and southern plains on Friday.
  12. OKpowdah

    November weather dicsussion

    Just a bit of disagreement over the NAO domain..
  13. OKpowdah

    November weather dicsussion

    Amazingly enough, much of Oklahoma is reaching the same target tonight.
  14. 0z Euro still putting together a show for the Plains around day 8. Big differences from the GFS, which tends to break ridging in the west, cutting off part of the trough in the southwest, and the arctic air trying to dive south is deflected northeast.
  15. OKpowdah

    The early speculation on winter 2013-14

    Tip, I don't see how you can think the Pacific doesn't influence the AO domain. In the more fundamental sense, take the distribution of tropical forcing in the equatorial Pacific, sketch a Hadley circulation accordingly, which will move the "Ferrel cell" ball bearing, thus putting some vertical torque on the polar cell. Or just take tropical forcing and the polar jet and see where the lower wavenumber Rossby rays go. All sorts of interaction. And unfortunately no matter how many three letter acronyms someone wants to come up with, it will always be a nonlinear system.
  16. OKpowdah

    November Weather Discussion

    Makes some sense that polar ozone would be at a surplus since we've been in this very prolonged Nina regime -> suppressed Pac convection and less water vapor punching into the stratosphere to destroy ozone. So the BDC has had full loads to drop off at the poles.
  17. That's a major pattern reversal, and as is usually the case, LR model forecasts were a little too quick with communicating it downstream (hence the chillier start to November in the east). But anyway by day 2 we have the massive Aleutian ridge, by day 4 the ridge breaks, and by day 6 huge full latitude trough in the west, and ridge in the east. What LR models are agreeing on now is a decent arctic intrusion into the western trough, and one heck of a temperature discontinuity in the central and southern Plains by around day 8-9. Looks like a classic Plains cold front.
  18. OKpowdah

    Griteater's Winter Outlook '13-'14

    Just came across this. Excellent discussion man! Well done.
  19. OKpowdah

    November Weather Discussion

    As "fakegfs" tweeted yesterday, the Euro is even better than the GFS at trolling.
  20. OKpowdah

    November Weather Discussion

    Timing the rest of the pattern against that wavebreak is crucial. The position of that massive ridge doesn't change, nor the amplitude or timing the break. It's what the break is acting on. Crashing against rocks or sand
  21. OKpowdah

    November Weather Discussion

    we'll keep you safe
  22. OKpowdah

    November Weather Discussion

    lol I mean, once you get enough of a consolidated PV max, the whole baroclinic positive feedback process kicks in ... surface circulation, and warm advection helping form ridging downstream, upstream of the Quebec shortwave. And so on. And in this case, with such a strong baroclinic zone, the timescale for this is super short. But we first need to get past that "critical amplitude" ..all or nothing
  23. OKpowdah

    November Weather Discussion

    One of the big issues we can't get past next week is the +NAO pumping up heights over the southeast. That just enhances the mass gradient (that's already there with the strong baroclinicity). The s/w energy in question is running into 250mb heights around 1056dm with WSW winds >150kts. Pretty hard to compress and amplify against. So you have this PV filament (string of shear of vorticity) that we want to consolidate into curvature vorticity, but 150kt WSW winds are constantly shooting any tiny PV maxima that develop eastward. So we're just left with that PV filament pushing SE while being stretched off to the NE and no potential for amplification of any sort.
  24. 12z GFS through day 5, maximum 500mb heights: PASY: 5771m PASN: 5754m
  25. When the technique fails ... lol. It's classifying the scene as uniform CDO region.
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