dallen7908

Percent of EPS members giving College Park, MD > 1, 3, 6, and 12" of snow/sleet during the next 10 days

Verbatim the 12 UT EURO day-10 storm would be a painful miss for you. Miller-A up the coast snow west of I-95 in NC ... Banana high etc. All in the game for now.

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.

22-34% of EPS members give the DCarea-PSUland > 6" of snow during the next 12 days. Much stronger signal than the previous 4 cycles where the percentages were 14-20%, 10-16%, 14-16%, and 6-18%.

Did Europe or anyone benefit from the SSW this year? Saw somewhere that the return of ENSO-like conditions could lessen the impact of the favorable MJO phases we are forecast to enter. That would be an ironic ending to winter and unwelcome support for your point.

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.

Euro's >6" of snow/sleet line runs east-west across MD perhaps 15 miles south of PA border

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.

Gradient pattern FTL? Forum Civil War?: Over the next 96 hours, 76% of 00UT EPS members give Westminster > 3" while only 6% of the members give Upper Marlboro the same.

Is it likely that the mean storm track in the upcoming gradient pattern will set up somewhere within the gray area?

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.

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

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.

Snow storms disappear and re-appear in the 6-10 day time frame. Noise Pattern changes disappear and re-appear in the 8-14 day time frame. Noise I'll keep the faith in a change to a favorable pattern at least for a few more forecast cycles

Hopefully, but it may be a wait; the EPS mean snow fall for College Park is 1.7" over the next 15 days. 18% of the ensembles give > 3" for snow/sleet during that period

Moderate snow now in College Park

SN- with a bit of rain mixing in - College Park

According to the EURO my high temperatures for January 31 - February 6th will top out in the 20s, 30s, 40s, 50s (twice), 60s, and 70s. Each day will be warmer than the last with the high temperatures ranging from 23 to 71.

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.

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.

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

Need some ratio help here

For my area, the EPS mean snowfall over the next 15 days is almost 3" (all during week 2), which is unusually low for a skewed mean this time of year. The percent of EPS ensembles with at least 3" of snow during this period is a disappointing 28%.

All I'm saying is that there's a chance with a discrete threat only a week plus a few hours away