October Discobs 2019

[WEATHER53]

On 10/21/2019 at 5:34 PM, Prestige Worldwide said:

Yesterday’s rainfall in our area 

It looks like a snow map.

[JakkelWx]

Maybe if it was a couple degrees colder.. on the brink of frost this morning. 38 degrees. Sun doesn't rise for another hour or so maybe we can eek out a 35/36 right around sunrise

[WxUSAF]

Low of 40.  No frost in my yard, but some of the neighbors roofs had a bit of frost.

[CAPE]

39 here

[wxdude64]

I broke the 32 barrier about an hour ago, so first freeze of the year here (barely). Currently 31.8/31.0 with a clear sky, saw the ISS go by just before 7am!

[mappy]

35 for the low

4.12" for Oct after Tuesday's rain. 

[EastCoast NPZ]

Another windshield scraper.  Perfect morning.

[WxUSAF]

USDA fields north of greenbelt radiated well as always. Lots of frost. Car thermometer said 37.

[midatlanticweather]

34.2 for a low in Purcellville 

[MN Transplant]

You all and your "radiational cooling".  45.1 for the low at home.

45 at DCA

35 at IAD

[mattie g]

24 minutes ago, MN Transplant said:

You all and your "radiational cooling".  45.1 for the low at home.

45 at DCA

35 at IAD

39 IMBY in Burke. Chilly waiting for the train.

[George BM]

Yeap.

[EastCoast NPZ]

Moderate drought on the heels of a 2 inch rainstorm in the Eastern areas seems odd.

[high risk]

18 hours ago, WxUSAF said:

Euro and GGEM pretty close lately and in today’s 12z. Not sure if that is coincidence or if the GGEM has gotten better lately. @high risk?

 

For sensible weather, that means both give the big cold dump out west next week which modifies as it moves toward us. 

 

    GGEM has made some improvements, but it's still behind the ECMWF and UKMET, although it's been closer to the GFS for medium range synoptic performance in recent weeks....

 

[Kmlwx]

36 minutes ago, EastCoast NPZ said:

Moderate drought on the heels of a 2 inch rainstorm in the Eastern areas seems odd.

It had been in the "severe" category. 2 inches still leaves a deficit. That map is typically a slow adjustment too since hydrology can be a trickle down effect at times. If we don't revert to a super dry pattern, you'll see that improve more next week. 

[osfan24]

GFS looks pretty wet for much of Sunday.

[nw baltimore wx]

Maybe just a fluke this run, but the euro and gfs have pretty solid consensus for central MD.

        

[wxdude64]

Much warmer morning in upper 30's here, about 30% cloud cover and a SSW very light breeze. Temps actually went up a couple degrees since midnight.

[GramaxRefugee]

Morning fog won't let go here in PGCo. I'm a bit surprised.

[Prestige Worldwide]

71 and plentiful sunshine in downtown Rehoboth right now. 

[wxdude64]

In grabbing a bit of lunch, awesome day to be working outside, currently double nickels and partly cloudy, but clouds are increasing.

[George BM]

Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1225 PM CDT Sat Oct 26 2019

   Valid 271200Z - 281200Z

   

...Shower activity ahead of the main frontal convection will limit
   instability and heating across northern and central VA northward.
   However, surface dewpoints in the mid to upper 60s are forecast,
   resulting in SBCAPE less than 250 J/kg across northern VA into the
   northern Chesapeake Bay vicinity. Ahead of the front, backed
   southeasterly winds in the vicinity of a pre-frontal trough will
   result in effective shear values around 30-40 kt. This should allow
   for some organized bowing segments within the QLCS and a few
   damaging wind gusts will be possible as convection quickly moves
   east/northeast.  Strong wind profiles as low as around 1000 feet,
   and backed southeast surface winds will lead to large, curved
   hodographs. If pockets of greater instability occur and
   surface-based convection develops, a weak/brief tornado cannot be
   ruled out across northern VA toward coastal MD....

[CAPE]

Mid 70s tomorrow with marginal risk of severe. woohoo. Late October football weather.

[frd]

Interesting he mentioned this , seems a lot of his followers are wondering what the hell he is talking about. Could be he wants some likes of the comment or maybe he believes it. 

Depends what side of the fence you are one. But, at the 12 hour mark that is a crazy jet stream. 

 

 

 

[WxUSAF]

Maue  recognizes the impact and reality of climate change, but his response after that seems often to be “suck it libs”, which earns him lots of maga followers who then get annoyed he acknowledges climate change. It’s weird.

[high risk]

Interesting Sunday morning for sure.    All guidance has some sort of squall line feature approaching DC Metro around mid-morning.   The HRRR sweeps it through most of the region, but the 00z NAM nest basically rips it apart as it arrives.        Even in the "worst case" HRRR scenario, it looks to be slightly elevated which would limit the wind damage threat, but it's close to being surface-based, so the MRGL risk is probably a fair call for now.

[yoda]

1 minute ago, high risk said:

Interesting Sunday morning for sure.    All guidance has some sort of squall line feature approaching DC Metro around mid-morning.   The HRRR sweeps it through most of the region, but the 00z NAM nest basically rips it apart as it arrives.        Even in the "worst case" HRRR scenario, it looks to be slightly elevated which would limit the wind damage threat, but it's close to being surface-based, so the MRGL risk is probably a fair call for now.

LWX in their AFD did mention a slight chance of a weak spinup

[Kmlwx]

It's about as good as we can get for this time of year short of a massively dynamic storm. I can recall a decent severe day in mid-November back when I was in high school. Maybe 2006? 

[yoda]

2 minutes ago, yoda said:

LWX in their AFD did mention a slight chance of a weak spinup

Evening updated disco from LWX:

Quote

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
By daybreak, a line of showers and storms will be approaching
the West Virginia Panhandle. This line, located just in advance
of the system`s surface cold front, will be situated beneath
strong mid-upper level forcing for ascent associated with differential
cyclonic vorticity advection ahead of a mid-level shortwave, as
well as the ascending branch (right entrance region) of the
upper jet. Conditions at the surface will be stable, but strong
temperature and moisture advection associated with the low-level
jet will produce instability aloft in advance of the line,
enabling elevated thunderstorms to develop along the line. This
line is expected to translate eastward through our forecast area
through the morning, and potentially into the early afternoon
hours. The main forecast question tomorrow is whether surface
based instability will be able to develop to the east of the
Blue Ridge in advance of the aforementioned line. Solid cloud
cover and showers will be ongoing in advance of the line, which
should act to limit heating at the surface and resultant
instability. Most model soundings show close to a moist neutral
profile through the lower atmosphere. However, if some surface
based instability were to develop, we`d have a parameter space
in place supportive of severe thunderstorms. With that in mind,
the Storm Prediction Center currently has portions of northern
Virginia, DC, and southern/central Maryland in a marginal risk
for severe weather.

In terms of specific threats, damaging winds will be possible
with any stronger downdrafts that form, given the nearly 60
knot low-level jet in place just above the surface. A brief,
weak tornado or two associated with mesovortices along the
leading edge of the QLCS can`t be ruled out either, given large
curved hodographs at low-levels and 0-3 km line-normal shear
values in excess of 30 kts. But again, these threats are very
conditional and will be tied to whether surface based
instability is able to develop. In terms of timing, this line is
expected to move across areas east of the Blue Ridge between
roughly 10 AM and 1 PM.

[high risk]

7 minutes ago, yoda said:

LWX in their AFD did mention a slight chance of a weak spinup

 

     The low-level shear will be fantastic.    It's just a question of whether the storms can become surface-based.    Right now, it appears that they won't, but it's not impossible.    Having the line arrive as late as possible, with no showers out ahead,  to allow for heating in advance is the scenario that would make things extra interesting around here.