dallen7908

The problem with the mean is that the distribution is becoming increasingly skewed because the mean is low and bounded by zero.  N=136 is a healthy sample size. 

"The Week 3-4 Temperature and Precipitation Outlooks are based primarily on operational dynamical guidance including the GEFSv12, CFSv2, ECMWF, JMA, and experimental guidance from the Subseasonal Experiment (SubX) multi-model ensemble (MME) prediction systems, with additional considerations for Madden Julian Oscillation (MJO) states, the El Niño Southern Oscillation (ENSO), decadal climate trends, and the evolution of the pattern from the Week-2 forecast ."

From last Friday's CPC forecast.  While pattern chasing should be be looking at the JMA or MME too? 
 

"Details we just can't know yet."

Details --> Whether or not there will be an east-coast storm

Details --> Whether it will snow in Washington, DC

Too bad CAPE isn't referring to the latter. 

... did you also observe a complete flip in the ensemble means of surface temperature for days 10-15?  That would be a more interesting ... and probably still wouldn't be too surprising. 

If you think we do wind well here you haven't been around much

Yes whenever it's windy here from mid-November through early April, the answer to the question: "Snow storm in (interior) Maine?" is usually yes

I usually root for a warm October - it seems to be  correlated with a cold/chances-for-snow winter.  Of course, I'm sure the correlation if it exists is 0.1 or so. 

It'd be kind of cool to watch opening day in a flizzard - but other than that I'm ready to move on too. 

1/3 7.5

1/7 2.25

1/16 2.25

1/28 0.5

2/13 0.1" (briefly reached 0.1" when T dropped to 34 during a snow shower just before 9) 

3/12 0.4"

13" for the winter (College Park)

College Park

no accumulation yet on the sidewalk driveway etc  but certainly accumulating on the mulch and even on the grass.

Transitioned from vertically-falling snow to fatties about 10 minutes ago - perhaps a good sign

Temperature has creeped up a bit over the last half hour but it could be due to some stray light sneaking into the dog house (our dog has never entered it) where the sensor is ... 

38 and sleet in College Park

Just dropped under 40 here in College Park has fallen 9 degrees since 6 AM - moderate to heavy rain 

14 minutes ago, WesternFringe said:

Serious question (and I am not complaining- I am excited about any snow tomorrow):

Why does NWS have Staunton in the 1-2" range on their expected snowfall map, but has a 66% probability that Staunton will get over 2"? 

Aren't those two things mutually exclusive?  They both have the 10:26 am time stamp.  As a teacher of math, I am befuddled by this. 

63 degrees here NW of Staunton

The probability values are an experimental automated product obtained using output from an ensemble of models.  It is one of several tools including models, satellite, radar, and observations used by forecasters when obtaining the forecast value of 1-2". 

Same plot shown above but for the College Park area. Nice omega within DGZ but as is usually the case; a warm nose to worry about

Spring Indeed

63/48 +/- 5 degrees beginning Monday and continuing as far as the ensembles can see ... 

I was a teenager in northeast Iowa during the 1978 storm;; I spent the evenings listening to coverage from powerful WWWE.  I was in the DC area during the 1993 storm; walking across snow/sleet drifts without sinking brought back memories of running across snow drifts as a youth in Iowa.

I'm cautiously optimistic that areas in the >50% category (below) will have accumulating snow (> a trace) over the next 5-days.  

The EPS snowfall mean at College Park for the next 15 days is 0.3" of which 0.1" "occurred" this morning.  The mean exceeded the 75th PCTL, which was ~0.15".  The GEFS snowfall mean for the next 10 days is also low ~0.1" mostly due to one member which gives us 3" on the 6th. 

This is quite unusual for February - in almost any pattern.  I'd be nervous to take the "under" of these model "forecasts". 

... Yes of course the ensemble mean adds little given how non-dispersive the members are and how skewed the precipitation distribution is at range but an ensemble of ensemble PCTLs is still useful, e.g., the 10th, 50th, and 90th percentiles of ensembles based on more than one operational model

1 hour ago, Weather Will said:

Latest ensemble runs for snow….

Indeed, the percent of EPS members giving the DC-area > 3" of snow during the 27 Feb - 2 Mar period has dropped to 2% after bouncing between 15 and 25% over 7 cycles (3 1/2 days).  Of course, there are only 2 possible outcomes.  So if the best you can do is 25% you're probably headed to nada in the end.  Hoping for a dead cat bounce over the next cycle or two to keep us interested.  

T-3 weeks to Hail Mary time.  Hopefully, we'll experience a few "forward breaking waves" before then.

You need to squint hard to see the 27 February event at BWI on the NAEFS; a weak signal is seen at Norfolk, VA.  The percent of EPS members giving DC 3" of snow/sleet/freezing rain(10:1) through 12 UT March 2 has equalled 22, 14, 26, 20, and 18% over the last 5 cycles (22% value is from 00 UT last evening

Guess this is what happens when an inch of (forecast) freezing rain is assumed to be snow.   See earlier posts for a more clear but still fuzzy picture of what we may face if the cold-bias of the GFS disappears between now and next Friday. 

For what it is worth, the percent of EPS members giving DC greater than 3" of snow/sleet through 0 UT Feb 26 (10 days from yesterday evening) has increased from 2 to 8 to 18% over the last 3 cycles (00 UT Feb 15, 12 UT Feb 16, and 00 UT Feb 16).  The modeled window for snow begins on the evening of the 24th. 

1/3 7.5

1/7 2.25

1/16 2.25

1/28 0.5

2/13 0.1" (briefly reached 0.1" when T dropped to 34 during a snow shower just before 9) 

12.6" for the year in College Park

Glad to see "around an inch" in the NWS forecast rather than the dreaded "up to an inch" or "less than a half-inch".  Of course the CWG is going with the dreaded "T to 1" for those of us east of the fall line with the latter to cover measurements on "grass and mulch".

Encouragingly much of any accumulation may occur when it is light between 6:45 and 9:00 AM or so. 

18 minutes ago, psuhoffman said:

There is a system coming through the west next week but its marginal if its going to drop enough snow to be worth a trip out there.  Mammoth CA might get a decent dump middle of next week.  It looks pretty bare elsewhere.  

Mount-Sainte Anne might be an option depending on track

7 minutes ago, psuhoffman said:

I’m 10 times more upset that all guidance is showing a huge rainstorm followed by a hard freeze all the way to the arctic circle destroying the surface at every ski resort right better Presidents’ Day weekend.   Even out west is a mess where they’ve had little snow in a month. I can’t even find a damn place to ski that will have powder anywhere in the lower 48 next weekend. 

"... And every time I hear westerners rag on the “ice coast,” I take pride in the fact that most of them would struggle to ski it. Keeping your edge at 50 miles per hour on ice, feeling the chatter of your skis up your spine, requires more skill than taking face shots of cold-smoke powder.

So, to my uncle’s question: Why would anyone ski the East? For starters, it will make you a superior skier. "

Jay Bouchard from Outside Magazine

Trend over the last 4 GFS runs -