WxUSAF

Storms firing along the outflow boundary in HoCo and MoCo. Hope I get some rain...

HR^3 has a MCS remnant coming through in the predawn time period.

Woo sprinkles.

Just heard thunder, but looks like the storm will stay to the NW of me while also efficiently robbing the area of CAPE so the next line skips over me.

Woo for scattered gusty showers!!!

My hands have been very dry.

Maybe it did and I just forgot. But I remember having no issues driving to work.

I thought 3/25/13 was ridiculous. I had ~6", nothing on the streets, didn't even get a day off work, and it was all gone by lunch.

My WAG is IAD and BWI at least get a fraction of an inch in February and then all 3 airports get 3" of slop overnight in mid-March that melts by 10am. It's like 12-13 but even worse.

I think that's the idea, yes. So low southern ice and the ridiculously low Arctic ice gives you that insane figure.

Ooof. Holy shi-t.

Saw on Twitter that the IAD sounding had 1.8" of precipitable water, which sets the all-time Dec-Apr record.

What's the most anomalous single day departure on record for the airports? We're looking at a +30 or so for xmas eve?

New paper linking the cold winter of 13-14 with the warm central Pacific SST anomaly. http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL063083/full

10 below normal months at BWI in the period of November 13-February 15. February 15, January 15, November 14, August 14, July 14, April 14, March 14, February 14, January 14, November 13 That's a pretty impressive run given climate and UHI both progressively working against below normal temps. Maybe some of the stat-minded folks can tell us how exceptional it is?

JB is so hilariously ignorant Joe Bastardi @BigJoeBastardi · 5h5 hours ago Amazing how Mars has climate change with atmosphere about the same %co2 as Venus,but much less dense. Isnt that special?

1st time with 4 consecutive BN months at BWI since 1970 apparently? According to Tony Pann.

That's a gimmee today. Same for IAD.

Wow…62F is the record. Lowest record high max of the entire month and only set 2 years ago! That's a gimmee. IAD's record is 61F, also set in 2011. Both of those are probably locks. DCA is 68F. That's going to be close.

Here's a nice reference for the upper air pattern when a KU is about to happen:

^that was the greatest quake meme ever

Speaking of CAPE and following up about the skew-T discussion, the amount of CAPE can be directly calculated from the skew-T by adding up the area between the parcel trajectory (along a moist adiabat) and the environmental temperature profile. So, if there's a lot of room between the two, you can know the CAPE is high before looking at the calculated parameters directly. The "opposite" of CAPE is CIN (convective inhibition) and is also measured in J/kg. CIN occurs when the parcel trajectory will lead it to be colder than the environmental temperature. If the parcel is colder, it's not buoyant in the free atmosphere and needs to be forced to a height in the atmosphere where it is bouyant before it can freely begin to rise. When people speak of a "cap", there means the atmospheric profile has a certain amount of CIN to overcome.

Bingo.

"Vort" refers to vorticity maximum. Vorticity is a measurement of spin in the atmosphere, where positive vorticity refers to counter-clockwise rotation, which in the northern hemisphere, is associated with cyclonic storms. In strict mathematical terms, it is the curl of the velocity vector. Associated with that, an important quanity is "positive vorticity advection (PVA)". Areas experiencing PVA are having the vorticity increase overhead, and that is associated with upward vertical motion and can encourage cyclogenesis. The "X" on a 500mb vorticity chart usually is the location of maximum vorticity within a trough. "Shortwave" (sometimes abbreviated "s/w") is short for "shortwave trough", which I think is also your reference to "trough". However, shortwave troughs are distinct from LONGwave troughs. Shortwaves are embedded in a broader longwave pattern. When people say "we want a trough in the east for cold weather", they are referring to a longwave trough. Shortwaves are associated with positive vorticity maxima (in the northern hemisphere), so many times those 3 words you referenced are used interchangeably even if they technically mean different things. Shortwaves are often associated with baroclinicity (a potentially unstable difference in temperature) and thus can be associated with cyclogenesis and/or thunderstorm development.

I see dtk replying, so I hope he fields the verification score question since I'm not going to. I think the SREFs have some value inside of 72 hours and certainly inside 48. I really enjoy looking at the plume charts to get a sense of the spread and clusters of the different solutions. The NAM certainly struck out this weekend, but I'm certainly not as down on it as zwyts and Ian. Much of my forecasting in the AF was very short-range, so perhaps I just didn't notice if/when the NAM blew a 72 or 48 hour forecast. But it always did pretty well for me, and indeed, we were obligated to use it unless it was really REALLY out to lunch. I use Raleighwx's website for most of my model analysis, but I don't have a favorites menu full of wx links like many on here. I wouldn't worry about GGEM ensembles. The GGEM doesn't go out to 10 days on its home website, so I wouldn't bother looking for it even if it exists.