Preliminary Winter 2004-05 Forecast

[CaptinCrunch]

Welcome back USAwx1.

[Stormsfury]

Nikolai,

While I believe there is some opportunity for greater snowfall in the DCA area, 30" or greater winters are not all that common (21 of 116 winters since 1888-89):

Code: Select all

Season   Snowfall
1898-99   54.4
1995-96   46.0
1921-22   42.5
1891-92   41.7
1904-05   41.0
1957-58   40.4
2002-03   40.4
1960-61   40.3
1910-11   39.8
1978-79   37.7
1890-91   37.1
1966-67   37.1
1917-18   36.4
1908-09   36.0
1899-90   35.6
1963-64   33.6
1935-36   31.8
1934-35   31.4
1986-87   31.1
1892-93   31.0
1933-34   30.7


Nevertheless, sometimes such winters come in clusters. For example, 1890-91 through 1892-93 and 1933-34 through 1936-36 saw 3 consecutive winters with 30" or more in Washington, DC. Moreover, the 1890s saw 5 such winters.

The last decade to see more than one was the 1960s (3). The 1940s saw none.

a GOOD many of those years followed after a very active TC season ...

[Stormsfury]

BTW…for anyone wondering…this is USAwx1. Nice to be back for the time being after my 5 week hiatus. I won’t be posting as much as I have been but will try to at least 3 or 4 nights a week. Just wanted everyone to know that---yes---I am still alive and well. LOL

Welcome back, my friend ... good to know you're still around ...

[wxguy25]

Welcome back, my friend ... good to know you're still around ...

Thanks. BTW check out the 12z ECMWF. Major phasing episode over the lakes leads top the development of HUGE/cold/displaced PV for this time of the year.

IF ONLY this was the middle of winter we would be talking MAJOR...MAJOR trouble, (or could this be a sign of things to come?) but since its only mid OCT the PV wont last long in that position and race northward into canada reaching Hudson bay on D3. The trough then lifts out after that, so this can possibly be seen as the catalyst for a change in the pattern as the trough re-develops in the west on D4 and 5 and the PV heads back into western CANADA. thats the interesting part, but take note to the strong split in the flow w/ REX blocking pattern over the EPAC---textbook EL NINO-west QBO type sequence of events on the initial and D1.

http://vortex.plymouth.edu/gifs/041015004243.gif
http://vortex.plymouth.edu/gifs/041015004722.gif
http://vortex.plymouth.edu/gifs/041015004752.gif

The PV will pump the ridge to the east of it as it heads into Canada which sends the NAO negative on D4 per the 12z ECMWF Notice the Omega style ridge nosing up toward the southern tip of greenland.

http://vortex.plymouth.edu/gifs/041015004955.gif

Ahead of the system there is the potential for some severe weather along the east coast with this as Strong CVA (leading to intense lift) and corresponding height falls ahead of the potent vort overspread the region. This should be aided by impressive Mid level lapse rates and potent LLJ. You can still get SVR weather even in spite of the probable lack of instability when strong forcing is present.

[Stormsfury]

Yeah ... I noted on the US Weather Watch Forum that PurdueWx posted ECMWF maps that the NEG TILT trough carving out a cutoff low which becomes a PV but is transient, and zips off to the NW faster than a drunk guy realizing that he went home with an ugly woman ...

Impressive line of low-topped thunderstorms/squall line in Eastern/Central TN right now (with very limited moisture returns in the wake of the first s/w which exited early this morning) ...

The links above expired and no longer exist on the vortex server ...

SF

[wxguy25]

Yeah ... I noted on the US Weather Watch Forum that PurdueWx posted ECMWF maps that the NEG TILT trough carving out a cutoff low which becomes a PV but is transient, and zips off to the NW faster than a drunk guy realizing that he went home with an ugly woman ...

Impressive line of low-topped thunderstorms/squall line in Eastern/Central TN right now (with very limited moisture returns in the wake of the first s/w which exited early this morning) ...

The links above expired and no longer exist on the vortex server ...

SF

it's transient for two reasons, the first is that it's simply too early in the season for the PV to be displaced that far south over the lakes. the seasonal position of the westerlies is still too far north to permit it. Secondly, the PV in the means at least through the First part of DEC should be over western Canada or AK and slowly progress eastward through the season.

There will be times though when the rex-blocking pattern develops off the west coast that the trough comes back into the east b/c the jet has to go around it. Add in a negative NAO and some spectacular stuff can happen toward the end of NOV and in DEC. Another Xmas nor'easter?

the second half of the winter looks ALOT more promising in the EUS.

Right now everything is backing up (discontinuous retrogression). So the longwave trough will re-appear in the west and the SE ridge may try to make a stand in the EUS the first 1/2 of NOV.

But getting back to the squall line in TN. Check out the strong vorticity gradient over the region. a change in vorticity of almost 20 units over a short distance of the region, and areas to the east are experiencing strong CVA which is leading to forced ascent and the development of the squall line. You can see the s/w VERY clearly on the WV imagery and 00z RUC analysis. The developing negative tilt to the trough just makes it worse.

[Stormsfury]

Whoa ... dodging a SERIOUS bullet here ...

if the boundary layer air was more humid/warmer (thank you, passage of the first cold front this morning), coupled with a little more in the way of instability ... look out! ... squall line in Eastern TN occurring in SFC temperatures only in the 50's ... a very dynamical s/w indeed ...

SVR WX still possible in the Eastern Carolinas ... in fact, SWS just released from Charleston (scrolling across the screen right now) in regards to late tonight and tomorrow morning before the frontal boundary moves thru ...

[wxguy25]

Of course, if instability was more plentyful, we would be talking about a major severe weather outbreak considering the kind of dynamics that are associated with this system. But there have been several instances, I'll cite two events in the Northeast Last fall and the MAR 2002 Serial Derecho as examples of significant severe weather outbreaks that were dynamically driven vs. more common spring and summer events where you have plenty of low level moisture (high Td's) and warm temps which combine to develop areas of significant instability.

[roebear]

The complete discussion can be found at: http://www.storm2k.org/don.html

Excellent work don, I enjoyed it immensely and will keep an eye on this thread!

You've covered most of the indicators I look at, but I also weight heavily for my own work what I call "natural indicators", pattern changes in my local environment that occurred during months previous to other winters that I have records for going back some 40 years. i.e., almanac type stuff that most here probably have no interest in. I just want to note that all that "stuff" agrees with a very cold winter in my area (PA), but I cannot nail down expected snowfall at this point.

[donsutherland1]

Thanks Roebear for the kind words.

I did give some weight to more local data e.g., with respect to Boston, I noted "A regional precipitation and temperature profile for Boston suggests..."

However, I'm still working on obtaining more local data and tying it to the global indices. Boston is a test case for this.

At the same time, I'm looking further into the PNA and NAO, taking a more global approach that considers possible teleconnective effects to improve accuracy as to the predominant sign of each. I know that a UK-based group has forecast a positive NAO this winter per lagged SSTA data and Northern Hemisphere snowcover. At this point in time, I'm not sure that this will be the case and by mid-November, I'll have my own firmer idea on the NAO.

[roebear]

Thanks Don,
I watch the NAO closely and was not aware of a positive NAO forecast for this winter. I'll be watching your work with interest and trying to dig some of my own up also for this important winter weather indicator.

[Brent]

Nice forecast Don. I like the below normal temperatures here. Hope it snows.

[deguy50]

thanx

[Wnghs2007]

Nice forecast don. Keep up the great work.

[Anonymous]

I have to agree 100% with Don here. I think the storm path will favor Colorado, texas, texas pandhandle lows, west and east gulf lows. I think D.C maybe on the warmside of these lows, although as someone mentioned earier, 1 storm could change that. Don, great job!

[CaptinCrunch]

Don,

As you know the NOAA released their "UPDATED" 2004-05 Winter Outlook, what are your thoughts, agreements, and disagreements with the forecasted outlook.

Thanks,

[gunner1551]

(My preliminary guess at the winter this year in BC)
Well if all the really cold artic air comes down from Canada this winter it doesnt matter were you are you will see some snow (Unless you live in Mexico) and colder temps all around this year. For instance last year in Bc we got about 3 feet of snow in the year. But the year before that we only saw maybe 5 inches all year. And in 2001 we got 4 feet of snow and it was -25 C without wind chill. It really does matter where the cold air hits for the whole year. I am expecting about 3 and a half feet this year in BC this year with some nasty arctic blasts coming down. Last year are ski mountain got a base for over 35 feet packed so i am hoping for another good year.

[donsutherland1]

CaptinCrunch,

Many apologies for the much delayed reply. This has been a very busy week for me.

Briefly, I like how the NOAA temperature forecast is evolving. My area of below normal temperatures is more expansive.

In terms of precipitation, I see below normal precipitation along the Gulf Coast and below normal to normal precipitation running north to the Midwest.

Best wishes.