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Medium Range Discussion Winter 2011-12


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This is much better. Nice cool down for 3 weeks in Feb, good to see finally

Compliments from the Pacific. If the Atlantic wakes up, it would be a lot colder for the east coast. It looks increasingly probable that the eastern third plus the southern plains will be colder than average by Feb 20th... and I doubt the last week of Feb will erase those anomalies.

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nGEeA.gif

pjYyy.gif

epNsA.gif

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Thanks for the explanation, DTK. I believe that addresses the seeming difference.

With respect to the base period, the following language is provided on the daily ensemble runs:

Weeklies: "...The forecast displayed here is the ensemble mean of 16 forecast members from initial conditions of the last 14 days. All anomalies are with respect to the lead dependent model climatology from the hindcast period (1999-2010) without any adjustment."

Monthlies: "...The forecast displayed here is ensemble mean of the latest available 16 or 21 members. All anomalies are with respect to the climatology from entire hindcast period (1982-2010) without any adjustment."

Right, and there is actually conflicting information (the monthlies page I linked earlier says:

"Aomalies are with respect to 1999-2010 hindcast climatology."

Except for SST's, which use the 1982-2010 hindcast climo. This is different than the (uncoupled, lores) CFSv1, which did use a 1981-2006 climo)....but I digress.

There are in fact two climatologies that were produced from the hindcast dataset (1999- and 1982-). I'm guessing this has to be related to the introduction of ATOVS into the reanalysis. I'd honestly have to do some more sleuthing and ask around to get to the bottom of it all.

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The HPC has a lot of interest in the Pacific at this time. And possible additional G-IV/C-130 missions has been tasked as well as the 2 C-130 missions from Alaska.

NOUS42 KNHC 301730

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1230 PM EST MON 30 JANUARY 2012

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

VALID 31/1100Z JANUARY TO 01/1100Z FEBRUARY 2012

WSPOD NUMBER.....11-061

I. ATLANTIC REQUIREMENTS

1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS

1. FLIGHT ONE -- TEAL 71

A. P55/ DROP 9 (45.0N 157.0W)/ 01/0000Z

B. AFXXX 09WSC TRACK55

C. 31/1830Z

D. 16 DROPS AS PUBLISHED ON TRACK

E. AS HIGH AS POSSIBLE/ 01/0600Z

FLIGHT TWO -- NOAA 49

A. P55/ DROP 9 (45.0N 157.0W)/ 01/1200Z

B. NOAA9 10WSC TRACK55

C. 01/0730Z

D. 16 DROPS AS PUBLISHED ON TRACK

E. 41,000 TO 45,000 FT/ 01/1800Z

2. SUCCEEDING DAY OUTLOOK:

A. POSSIBLE TEAL C-130J MISSION FOR

P56/ DROP 9 (44.3N 151.0W)/ 02/0000Z.

B. POSSIBLE NOAA G-IV MISSION FOR

P56/ DROP 9 (44.3N 151.0W)/ 02/1200Z.

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Daryl, are there any stats yet on the CFS2 weekly forecasts? I tried finding some and failed.

I'm sure there are stats/plots somewhere, but I can't find anything online that is regularly generated (I only see the skill posted from the hindcast model for the tri-monthly/seasonal forecasts).

When I'm in the office tomorrow I'll ask someone from the CFS team if/where they have skill from the weeklies in the hindcast model posted.

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I'm sure there are stats/plots somewhere, but I can't find anything online that is regularly generated (I only see the skill posted from the hindcast model for the tri-monthly/seasonal forecasts).

When I'm in the office tomorrow I'll ask someone from the CFS team if/where they have skill from the weeklies in the hindcast model posted.

I'd appreciate it. My CWG post gnerated a question to Jason by a climatologist.

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Right, and there is actually conflicting information (the monthlies page I linked earlier says:

"Aomalies are with respect to 1999-2010 hindcast climatology."

Except for SST's, which use the 1982-2010 hindcast climo. This is different than the (uncoupled, lores) CFSv1, which did use a 1981-2006 climo)....but I digress.

There are in fact two climatologies that were produced from the hindcast dataset (1999- and 1982-). I'm guessing this has to be related to the introduction of ATOVS into the reanalysis. I'd honestly have to do some more sleuthing and ask around to get to the bottom of it all.

Many thanks DTK. Don't worry too much about it. It was just something I came across and wasn't sure about.

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That will most likely yield to enhanced convection in MX and the Caribbean. To be honest, I am thinking if the formation gets together on the 11th like on the 00z GFS, it might as well torch us. The thing with all of these subtropical entities is that they phase into the cold front, and the upstream energy is always too late.

The set-up does not look bad on the 10-11th, maybe if the cold front makes it to the Northeast Coast before the Subtropical Low will there be enough phasing with the upstream energy to create a decent winter event. Will it happen? I'd it say it depends mostly on the speed of the Subtropical Low and how fast it progresses. I honestly do not care what happens but it will be interesting to watch.

p.s. I am happy about running outside tomorrow. I can't wait for the warm temps this week!

TNE

I cant remember seeing a MJO wave of this amplitude.

It looks like we'll finally get some favorable tropical convection though.

ensplume_full.gif

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Two notes on the AO:

1. The daily values for January 29 and 30 have been recalculated. The initially reported values were -4.441 and -4.464 respectively. The recalculated figures are -2.981 and -2.500.

2. Today's reported AO is -2.151. It should be noted that the GFS ensembles tank the AO toward mid-month. That kind of outcome would be consistent with the 2/8-15 period turning out cold in the East, if it verifies.

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Two notes on the AO:

1. The daily values for January 29 and 30 have been recalculated. The initially reported values were -4.441 and -4.464 respectively. The recalculated figures are -2.981 and -2.500.

2. Today's reported AO is -2.151. It should be noted that the GFS ensembles tank the AO toward mid-month. That kind of outcome would be consistent with the 2/8-15 period turning out cold in the East, if it verifies.

The recalculation is a bit deal and minus 4 type events usually last awhile, I don't think you can use than generallization about weaker negative episodes.

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So, what's this MJO thingie going to do if it reaches >2-3 SDs amplitude? If it's on phase 7 -- as it's forecasted -- a very anomalous split flow pattern, with a huge ridge near the west coast (like it's forecasted by all models) it's gonna popup. Also, an active STJ and anomalous low heights are probably on tap for MX, but for the eastern third it has to progress past phase 7, as it doesn't teleconnect well with colder temps/storminess. The good news (for cold lovers) is that the W Coast ridge will probably tap into some arctic air, as it morphs into an -EPO ridge. If it comes to pass and the MJO progresses to phases 8 & 1 without taking a dive into the CoD, then a cold pattern could lock for some time for the east coast...that'll probably be past Feb 10th.

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So, what's this MJO thingie going to do if it reaches >3SDs amplitude? If it's on phase 7 -- as it's forecasted -- a very anomalous split flow pattern, with a huge ridge near the west coast (like it's forecasted by all models) it's gonna popup. Also, an active STJ and anomalous low heights are probably on tap for MX, but for the eastern third it has to progress past phase 7, as it doesn't teleconnect well with colder temps/storminess. The good news (for cold lovers) is that the W Coast ridge will probably tap into some arctic air, as it morphs into an -EPO ridge. If it comes to pass and the MJO progresses to phases 8 & 1 without taking a dive into the CoD, then a cold pattern could lock for some time for the east coast...that'll probably be past Feb 10th.

Yep, I'm definitely in agreement with your thoughts. The main issue that the modeling is that the MJO might struggle to get beyond phase 7 with both the UKMET and ECMWF showing a significant loss of amplitude (with the former never escaping out of phase 7) as the MJO progresses. The GFS continues to be the most bullish with respect to both amplitude and forward propagation of the MJO. This is in large part what supports the continuation of the -AO, one which would be a much more favorable configuration for eastern US cold in comparison to the current regime.

2q8u4d0.gif

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You are defiant but you agree? How?

Haha small typo on my part :axe:

One of the points I have been harping on is the Convective feedback of the MJO that will help enhance the subtropical ridging in the Central pacific. You can see here that the 250 hPa temperature anomalies are +3-4 sigma thanks to the blossoming convection of the MJO, which is completely overwhelming the La Nina signal which would normally produce cooler than normal temperature anomalies aloft in the central and eastern Pacific due to suppressed convection.

2uel2yc.gif

The La Nina signal was present most of January (as evidence in the 1-17-12 GFS analysis image which shows widespread -1.0 sigma temperature anomalies seen above) when the MJO was diffuse and weak, but now that its kicking up and getting into phase 7, it will help to pump the subtropical ridge over the Central Pacific, which will in turn tighten up the polar jet b/w 30-40N across the central Pacific. As the MJO progresses, so to will this jet streak, and so to will the left exit region of the jet, which will enhance storminess across the east Pacific due to increased upper level divergence.

A shift in the development region of mid-latitude cyclones will also shift the trough/ridge configuration that we have seen for a large portion of the season. Where a mid-latitude cyclone develops, there must be a downstream response of ridging in order to support baroclinic development. This ridging will now occur across the west coast of North America which should support a +PNA due to this enhanced ridging. This is why generally MJO's that enter phase 8 and beyond typically lead to a cold signal in the eastern united states, because of the tropical signal forcing a shift in the development region of mid-latitude cyclones. That is also why the GFS and its ensembles have been supporting PNA ridging starting in the 5-7 day range.

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Euro ENS 11-15 are a disaster

I'd wait to jump the gun on the euro ensembles .. They've been quite unreliable with the longer range forecasts ( as most guidance has been.) let's see if the euro weeklies on Thursday agree with Monday nights which showed a 2 week period of a -NAO and +PNA.

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In character with what has been an unusually warm winter, February has gotten off to a warm start. At 6 a.m., numerous East Coast cities had low temperatures in the upper 40s and even 50s. Some cities included:

Baltimore: 50°

Boston: 36°

Bridgeport: 46°

Charlotte: 47°

Harrisburg: 44°

Hartford: 45°

Islip: 48°

New York City: 52°

Newark: 49°

Norfolk: 51°

Philadelphia: 48°

Providence: 37°

Raleigh: 51°

Richmond: 55°

Salisbury: 55°

Washington, DC:

...DCA: 50°

...IAD: 53°

Wilmington, DE: 51°

Finally, yesterday's run of the CFSv2, the final run of January, also indicated widespread warmth in the CONUS and southern Canada for February.

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Two notes on the AO:

1. The daily values for January 29 and 30 have been recalculated. The initially reported values were -4.441 and -4.464 respectively. The recalculated figures are -2.981 and -2.500.

2. Today's reported AO is -2.151. It should be noted that the GFS ensembles tank the AO toward mid-month. That kind of outcome would be consistent with the 2/8-15 period turning out cold in the East, if it verifies.

I would not even refer to a GFS operational NAO/AO forecast past the resolution change.

That said, for where it is even worth tracking on that model (d+8)...the latest NAO forecasts are trending neutral (even positive in some cases) and the AO is also trending weaker.

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Uncle, how does the 1971-1972 analog look so far?

71-72 was a little colder so far...74-75 is a better analog now...We have more snowfall this year than both those years combined before February...

year...Dec...Jan...

71-72...40.8...35.1...

74-75...39.4...37.3...

11-12...43.3...37.3...

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