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dallen7908

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Posts posted by dallen7908

  1. Yesterday's bullish 12Z EPS suite was easy to toss because it was so out of line with previous cycles.  It showed a 22-34% chance* of > 6" of snow during the next 300 hours from DC to the MD/PA border.  The 00Z suite from yesterday gave us a 8-18% chance over 312 hours while this morning's suite gives us a 8-18% chance over the next 288 hours --- back to square one.  Wish they didn't use the same initialization time for each suite - would remove some of the noise. 

    *Obviously, I'm using the term chance loosely, as the percent of members showing > 6" of snow during the medium-to-long-range differs from our actual chances, which for percentages > ~15% are usually less than that for long-range forecasts due to the 10/1 rule and models' cold bias in the long term. 

     

  2. Certainly encouraging signals; could this weekend's storm serve as the 50-50 for next week's storm? 

    Mixed feelings about next Tuesday as I'll be in New England.   Have missed the last two significant snows here .. why not go for three in a row?  

    My snow chase isn't going so well so far ... I'll miss this Wednesday's New England storm because I'm still here, will arrive in time for the rainstorm on Saturday (signing up for the moonlight snow shoe walk that evening may not have been a good idea), and should return to DC before next week's hypothetical storm reaches NE but after it brushes or smashes DC. 

    That said, I'd be ok with being stuck in northern NH for an extra day or two as you deal with the big one.  ... and if my return flight is delayed maybe I'll experience it up there instead. 

     

     

  3. The Euro gives DCA > 5" of precipitation over the next 7 days half of which falls during this system, let's obsess over the 0.1" (almost) that is forecast to be snow. 

    Verbatim, 850 temperatures rise above 0C around midnight Monday morning; before which approximately 0.08" of precipitation falls. They then increase slowly and don't exceed 2 celsius until 0230 AM Tuesday before which approximately 0.5" of precipitation falls.  850 temperatures exceed 10 celsius by 7 PM Tuesday evening 

    1000-500 hPa thickness start at 544 dm and rise slowly. 1000-850 thickness remain steady at 130-131 dm until about 0230 AM Tuesday when they begin rising rapidly. 

     

  4. Snowfall mean may be up from 00 UT but signal is still noisy. 

    Over a 15-day period, the percent of EPS ensembles giving DC-area (northern MD) 3" of snow is 42(52%) for the latest run, which is more than the previous run 26 (42%) but the same as 24-hours ago 46 (54%).  The percent of ensembles giving DC and the northern MD folks a 6" snow is the same as the previous run (~20%) but less than 24 hours ago (~30%). 

    For the last several weeks there have been numerous "threats" in the 10-15 day range that evaporate inside of 10 days ...fortunately a few have re-appeared in the operational model around day 7 with considerable ensemble support. Will be interesting to see if that pattern continues. 

     

  5. 49 minutes ago, BristowWx said:

    The always part meant that the extended always looks better, seemingly, by day and then steps back a night.  Nothing to do with showme, he is just the first expert poster to post in the a.m.....I love that guy he is top three contributor. 

    I agree.  I remember checking one Sunday morning at 8 AM for a Showme post and being disappointed that he chose to sleep in. 

    • Haha 1
  6. EPS continues to highlight a period beginning Sunday evening the 10th for snow opportunities.  15 day mean of 5" is above the noise level and the percent chance for >3" is 50% and >6" is 30%. 

     

    SSS disclaimer: I'd lean towards the 14th on as I will be on vacation from the 14th - 19th near Mount Washington and have managed to miss the last two significant snows in the DC area due to vacation. 

  7. 2 minutes ago, Round Hill WX said:

    I can't speak for the last couple of years, but recently the GEFS has beaten the EPS in skill. This is the 11-15 day range over the last 90 days.

     

    DxxHN6EWwAExMZB.jpg

    Do you know when the forecast mean absolute errors for climatology equal those of the ensembles and GFS? From the above it looks like it could range from day 9-13 depending on guidance. 

  8. 1 hour ago, MN Transplant said:

    That is calling for all-time records in my home territory in southern MN.  The fresh snowpack there will help, but this isn’t 94 or 96.

    I grew up on a farm in northeast Iowa and have never experienced the -34 forecast for Waterloo although have seen it in the forecast on several occasions.  I've experienced many -20 to -25 nights and a few below that but never -34.  Until recently, I believe the all time record in Waterloo was -32 on March 1st.  

     

    Elkader has the all time low in my area of minus 50 something; guess that is safe. 

  9. 06UT GFS COBB http://www.meteor.iastate.edu/~ckarsten/cobb/cobb_help.pdf shows 3+ hours of snow or rain/snow at DCA (4 - ~7 PM Tuesday evening).  Total precipitation is on the 0.5". Temperature at 3 PM is 40 degrees so.  
    Date/hour    FHr  Wind    SfcT   Ptype   SR |Snow||Sleet|| FZRA|| QPF    CumSR|TotSN||TotPL||TotZR|| TQPF   S%| I%| L%
    190129/2200Z  64  32013KT  32.1F  SNOW    8:1| 0.9|| 0.00|| 0.00|| 0.119    8:1|  0.9|| 0.00|| 0.00|| 0.39  100|  0|  0
    190129/2300Z  65  30011KT  33.3F  RASN    0:1| 0.0|| 0.00|| 0.00|| 0.037    8:1|  0.9|| 0.00|| 0.00|| 0.42   66|  0| 34
    190130/0000Z  66  31012KT  31.5F  SNOW   20:1| 1.0|| 0.00|| 0.00|| 0.051   11:1|  1.9|| 0.00|| 0.00|| 0.47  100|  0|  0
    190130/0100Z  67  31010KT  32.8F  RASN    0:1| 0.0|| 0.00|| 0.00|| 0.011   11:1|  1.9|| 0.00|| 0.00|| 0.48   78|  0| 22
    

    Indeed so quiet hear ... and I doubt we're all at Sunday services

  10. 41 minutes ago, Bob Chill said:

    Eps not enthused with the sun/mon coastal. Favors east/ots for now. 

    36, 20, 14, 2% of EURO ensembles give DC area >1, 3, 6,12" of snow with the coastal; so while "not enthused" is arguably correct its encouraging that "disagrees" would be incorrect

    How's that for a convoluted sentence. 

    • Confused 1
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