Jump to content

  • Member Statistics

    17,790
    Total Members
    7,904
    Most Online
    manaja
    Newest Member
    manaja
    Joined

December Medium/Long Range Discussion

yoda

By yoda,
in Mid Atlantic

 Share

Recommended Posts

  • Replies 4.8k
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

MillvilleWx
MillvilleWx

Night crew check in after 6 hrs of sleep (Will be heading back to bed shortly) Few thoughts gazing through things: 1. Initial thoughts holding with regards to ptype and where the best spots look to

MillvilleWx
MillvilleWx

What day is it? Ugh Mids suck Anyway, quick thoughts on 18z: I didn’t see any appreciable changes with regards to the overall setup. GFS is jumpy right now and is on the most extreme envelope of we

DTWXRISK
DTWXRISK

.  

Posted Images

BristowWx

BristowWx

Posted
Posted
10 minutes ago, JakkelWx said:

This is when you know that this will be another case of models finally getting it right but only under 48 hours.. that's just under a week from now...

Yeah.  Beats tracking a giant heat blob and hoping east winds will save you from a warm green Xmas.  This will be fun regardless.  Some sort of strong cold front is at least likely... I think. That’s about all.  

  • Like 1
Link to comment
Share on other sites
yoda

yoda

Posted
  • Author
Posted

It will change... but its fun to see the bolded 

Zone Forecast Product
National Weather Service Baltimore MD/Washington DC
341 AM EST Sat Dec 19 2020

DCZ001-VAZ054-191200-
District of Columbia-Arlington/Falls Church/Alexandria-
Including the cities of Washington, Arlington, Alexandria,
and Falls Church
341 AM EST Sat Dec 19 2020

.REST OF THE OVERNIGHT...Partly cloudy. Lows in the upper 20s.
North winds around 5 mph.
.TODAY...Partly sunny. Highs in the upper 30s. Light and variable
winds, becoming south around 5 mph in the afternoon.
.TONIGHT...Mostly cloudy. Lows in the lower 30s. South winds
around 5 mph.
.SUNDAY...Mostly cloudy. A chance of rain and snow showers in the
morning. Patchy fog. Highs in the lower 40s. South winds around
5 mph. Chance of precipitation 40 percent.
.SUNDAY NIGHT...Mostly cloudy. Lows in the lower 30s. South winds
around 5 mph in the evening, becoming light and variable.
.MONDAY...Partly sunny. Highs in the upper 40s.
.MONDAY NIGHT...Mostly cloudy with a chance of showers. Lows in
the mid 30s. Chance of rain 40 percent.
.TUESDAY...Mostly sunny. Highs in the mid 40s.
.TUESDAY NIGHT...Mostly clear. Lows around 30.
.WEDNESDAY...Sunny. Highs in the mid 40s.
.WEDNESDAY NIGHT...Mostly cloudy. Lows in the lower 40s.
.THURSDAY...Mostly cloudy with a 50 percent chance of showers.
Highs in the mid 50s.
.THURSDAY NIGHT...Mostly cloudy with a 50 percent chance of snow
showers. Lows in the upper 20s.
.CHRISTMAS DAY...Mostly sunny with a 50 percent chance of snow
showers. Cooler with highs in the mid 30s.
Link to comment
Share on other sites
CAPE

CAPE

Posted
Posted

For those into snow maps, both the GEFS and EPS have an inch or less for late next week, exception being the western highlands ofc.

Still 5+ days out with some variations in play as usual. My guess is either rain followed by a quick shot of snow, or the usual rain on the warm side of the front followed by CAA.

  • Like 2
Link to comment
Share on other sites
CAPE

CAPE

Posted
Posted

Latest take from Mount Holly-

Thursday into Friday the upper level low that was over the central United States is forecast to merge with another upper level disturbance diving south out of central Canada. The GFS has these two waves constructively interfering with one another with rapid deepening forecast. The ECMWF shows something similar, but is slightly slower. The CMC is by far the slowest here. Either way, the upper level dynamics with this system look very impressive with a 150 kt jet streak and accompanying 150/300 m height falls. Latest forecast soundings show a very impressive veered wind profile. The LLJ is also very impressive, with the 925/850 mb layer average forecast to be around 70 kts. Out ahead of the approaching cold front showers and some embedded thunder will be possible, with a change over to snow on the backside of the cold front also possible.

  • Like 2
Link to comment
Share on other sites
aldie 22

aldie 22

Posted
Posted
2 minutes ago, Ji said:
38 minutes ago, CAPE said:
Looks like the severe thread might get a little action lol.

Yep this is going to be a disaster

Yep a nice rainy Christmas with mid to upper 50's sounds about normal to me. Throw in a flash flood and a few tornados while we are at it. At least December 26th will be cold when everyone's power will be out.

  • Weenie 1
Link to comment
Share on other sites
WinterWxLuvr

WinterWxLuvr

Posted
Posted

Place me in the euro camp. IMO there will be no low on a front. There will be a low dragging a front through. We will get warmer than forecast in front of it, it will rain, the front will come through, the wind will exceed expectations, the temps will fall short of modeled lows. This is not the type of setup we have much of a chance with.

  • Like 3
Link to comment
Share on other sites
aldie 22

aldie 22

Posted
Posted
1 minute ago, WinterWxLuvr said:

Place me in the I HATE CHRISTMAS camp. IMO there will be no low on a front. There will be a low dragging a front through. We will get warmer than forecast in front of it, it will rain, the front will come through, the wind will exceed expectations, the temps will fall short of modeled lows. This is not the type of setup we have much of a chance with.

FYP

  • Haha 7
Link to comment
Share on other sites
WinterWxLuvr

WinterWxLuvr

Posted
Posted
49 minutes ago, leesburg 04 said:

Yep a nice rainy Christmas with mid to upper 50's sounds about normal to me. Throw in AS MUCH ALCOHOL AS I CAN GET and a few FEW SHITTY PRESENTS while we are at it. At least December 26th will be cold when everyone's power will be out, WHEN IM HUNG OVER AND TRYING TO TAKE THAT CRAP BACK.

FYP

  • Haha 6
Link to comment
Share on other sites
frd

frd

Posted
Posted

Today 1/3 of the CFS members go for dramatic weakening, ( zonal wind reversal ) but the look in general is a weakening PV over time in two phases. 

Early January may feature a deep- AO dive in my opinion and a significant storm threat.   

 

latest_cfs_u10.png

 

 

  • Like 2
Link to comment
Share on other sites
Ralph Wiggum

Ralph Wiggum

Posted
Posted
5 minutes ago, CAPE said:

Latest GEFS for early Jan. This isn't a good look if you are a polar vortex.

1609740000-Wf2bUcjuT5M.png

I dont consider myself knowledgeable on the 10hPa PV. In layman's terms, what does this weakening SPV translate to down in the trop? These SSWE's are discussed ad nauseum every year anymore it seems, but why? I know we can't say what it means for particular regions, but is it safe to assume with SPV weakening the PV doesn't allow it to 'stack vertically' over the Arctic Circle and can thus cause more displacing of the TPV and lobes to freely roam and wobble around rather than just remain anchored and stationary well to the N? Thanks.

  • Like 1
Link to comment
Share on other sites
CAPE

CAPE

Posted
Posted
1 hour ago, WinterWxLuvr said:

Place me in the euro camp. IMO there will be no low on a front. There will be a low dragging a front through. We will get warmer than forecast in front of it, it will rain, the front will come through, the wind will exceed expectations, the temps will fall short of modeled lows. This is not the type of setup we have much of a chance with.

I am inclined to agree with this, but I have to keep the faith since I apparently called for a while Christmas.:P

Link to comment
Share on other sites
CAPE

CAPE

Posted
Posted
45 minutes ago, Ralph Wiggum said:

I dont consider myself knowledgeable on the 10hPa PV. In layman's terms, what does this weakening SPV translate to down in the trop? These SSWE's are discussed ad nauseum every year anymore it seems, but why? I know we can't say what it means for particular regions, but is it safe to assume with SPV weakening the PV doesn't allow it to 'stack vertically' over the Arctic Circle and can thus cause more displacing of the TPV and lobes to freely roam and wobble around rather than just remain anchored and stationary well to the N? Thanks.

There are some good scholarly papers on the TPV/SPV relationship(and correlation to the AO), and its complex to say the least. They are completely separate entities, and sometimes there is little to no interaction(coupling) during winter. The reality is, for sensible weather, we are far more interested in the TPV, which is actually larger(multiple vortices), and directly influences our weather. We want a pattern that can disrupt and dislodge these vortices, and bring them south. That's how we get the cold down into the midlatitudes. It can happen at times even with a relatively strong SPV/+AO, as occurred 2013-14 with the big EPO/WPO block. In general though, when we have a persistently negative AO winter(which we clearly want) the SPV is a weakling, and it gets that way largely by transfer of heat into the upper trop/strat.

eta- @Ralph Wiggum

Good read here: https://journals.ametsoc.org/view/journals/bams/98/1/bams-d-15-00212.1.xml

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...