0z GGEM/GFS further Southeast w/ DEC 1-3...OV/Lakes/NE snow

[wxguy25]

0z FRI GGEM maintains Plains/OV/GL/NE snow threat DEC 1-3.

BUT w/ NO 50-50 Low in place or block everything hinges on the location of the PV. The GGEM has it a bit further Southeast than the 12z ECMWF which would suppress the s/w a bit more and cause it to track further SE.

Does this mean there is going to be a snowstorm in the I-95 cities? NO! It means that the track of the 500h low/shortwave trough should be from Central TX to the SE lakes which suggests a SIGNIFICANT winter storm for N KS, NRN MO, S WI, N IL, MI, OH, N NY, VT, NH, ME…NORTH of the track of the s/w and SLP area where the deformation zone sets up.









According to the GGEM the SLP would track from SE OK on WED to C PA on THU while deepening to 993mb.

IGNORE the warm bias, the GGEM is noted for it and its one of the reasons why you see the 1000-500mb critical thicknesses warmer than the required criteria for winter precip where I have just mentioned it would be based on the s/w and SLP tracks. Taken at face value they would imply rain for the aforesaid areas, and maybe if we were to be disgustingly objective—and assume a warm thickness bias-- one could argue FRZRA or IP due to a shallow cold layer below a warm wedge caused by elevated WAA.

There could also be YET ANOTHER severe wx episode in the warm sector.

The 0z GFS has a similar scenario. The PV is still strong and suppressive--notice 500mb heights ~486 dm over Hudson Bay. This is a GOOD position for the PV. BUT sill NO signs of a 50-50 low, although the downstream response to the PV forces the ridge to come back over Greenland setting up a weak –NAO.

The GFS s/w is an open wave and the associated trough initially is positively tilted whereas the GGEM is indicating a relatively mature/negatively tilted trough w/ closed low over the South central plains.



By 144hrs the s/w progresses eastward into the OV and COMES CLOSE to phasing w/ an appendage associated w/ the PV as it lifts ENE.



Based on the SLP track this would also be a SN event for the same areas as the GGEM suggested.

The system then merges w/ the PV and causes it to develop a DUAL structure w/ one center pin wheeling around the other. This is known as the FUJIWHARA effect.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_174l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_180l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_192l.gif
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_204l.gif

Ill remind you however the GFS resolution truncates to 77KM (T170) at this range…so please observe w/ CAUTION.

The FUJIWHARA effect describes two storms rotating around a fixed axis while moving in a specific direction. In our situation above the PV as a whole is moving to the East; however the two centers rotate around one another as the entire package moves eastward.

These may be UNSTABLE trends in the data so pay attention to future runs

[Guest]

Nice discussion and as well very nice to see everything starting to trend the way i have been discussing. If any snow imho is to fall in the NE then it will be in Boston on north which even in Boston it should changeover to rain.


BTW the last run of the EC i seen pretty much says the same.

[wxguy25]

Well the 12z GGEM was further northwest again but the 12z ECMWF and GFS after further south.

108hr

120hr

132hr

144hr

I’d also watch the kicker s/w which will push the DEC 1-3 event out of the four corners region and also baste CA w/ the PV in place and strong, some ridging over Greenland and an increasing PNA ridge the stage could be set for a Bigger OV/Lower Lakes/EUS event.

The 12z GFS was MUCH further south w/ the s/w-- taking it from OK on WED to off the MA coast THU.





The SLP moves ENE from the lower MS valley to the DELMARVA region by 138 hours; deepening below 1000mb while exiting off the coast South of CAPE COD and LI.







There appears to be a dual/coupled jet structure over the region w/ one maximum exiting off the NE coast and another moving up from the SW over the MA region. This would place the MA and SNE in the right entrance and left exit regions of the two jet streaks; areas which favor upper-level divergence and UVM on a Synoptic scale which would be enhanced ahead of the s/w.



200mb divergence (dashed lines) /500mb vorticity advection valid 0z THU

850mb convergence/RH valid 0z THU

Notice the area of strong low level convergence moving northward form the Mid Atlantic.

It would appear according to the GFS (if this scenario holds) that the large scale environment will be favorable for large scale lift and heavy precipitation w/ pronounced divergence above low level convergence, and DPVA over the region.



Even IF this solution would to verify I highly doubt the big cities w/ perhaps the exception of Boston would get in on any APPRECIABLE snowfall.

[Anonymous]

Great post, wxguy.


-Jeb

[Guest]

good post wxguy. However i as well as a few others thinks the 12z gfs is bunk. Shears everything out and as well that far of a south track just seems to unreasobale with the set up we have at that time.

More or less i am sticking with my ideas on this system thats posted elsewhere. Which more or less implies a good hit for the Lower Lakes, N.OV, and interior NE.

[wxguy25]

good post wxguy. However i as well as a few others thinks the 12z gfs is bunk. Shears everything out and as well that far of a south track just seems to unreasobale with the set up we have at that time.

More or less i am sticking with my ideas on this system thats posted elsewhere. Which more or less implies a good hit for the Lower Lakes, N.OV, and interior NE.

its a typical GFS bias, always too suppressive. I agree with the idea that the GFS is well off base. The 12z ECMWF is probably the best solution right now. Thats one of the reasons why i suggested in my posts that the GFS trends are UNSTABLE.

[Guest]

good post wxguy. However i as well as a few others thinks the 12z gfs is bunk. Shears everything out and as well that far of a south track just seems to unreasobale with the set up we have at that time.

More or less i am sticking with my ideas on this system thats posted elsewhere. Which more or less implies a good hit for the Lower Lakes, N.OV, and interior NE.

its a typical GFS bias, always too suppressive. I agree with the idea that the GFS is well off base. The 12z ECMWF is probably the best solution right now. Thats one of the reasons why i suggested in my posts that the GFS trends are UNSTABLE.

Agreed. I think in anoer couple of days or so the GFS will start to come around as was the case last week.

So far it appears to me so far this year that the EC, GGEM does very well in this time frame while the GFS keeps flipping where as when we get into the 72hr time frame or so the GFS begins to takes over.

[Stormsfury]

The GFS just doesn't appear to be handling SBJ energy worth a crap, and generally speaking, I saw a lot of mishandling of the SBJ in 2002-2003, and I expect the same thing again as long as the SBJ remains active ...

SF

[wxguy25]

The GFS just doesn't appear to be handling SBJ energy worth a crap, and generally speaking, I saw a lot of mishandling of the SBJ in 2002-2003, and I expect the same thing again as long as the SBJ remains active ...

SF

which means the GFS will have a hard time w/ phasing situations. the UKMET usually does a better job in those cases.

[Wnghs2007]

Hmmmmmmmm.....Even thought the 12z EMCWF seems to still have the polar vortex way up there in Canada. And the block up there seems to be gone at the 10 days average. The Eastern US still looks to be pretty cold and as stated from DT...If that 12z is right...DING DONG THE RIDGE IS DEAD!!!!

[wxguy25]

Hmmmmmmmm.....Even thought the 12z EMCWF seems to still have the polar vortex way up there in Canada. And the block up there seems to be gone at the 10 days average. The Eastern US still looks to be pretty cold and as stated from DT...If that 12z is right...DING DONG THE RIDGE IS DEAD!!!!

Block Gone? Thats not what i see. I see a pronounced split flow over E ATL w/ well defined REX BLOCK. I also see the trough amplifying over Scandinavia that would allow the block to migrate NW toward greenland setting up a STRONG -NAO after DEC 9.

IF the Midwest, Lakes and Northeast winter storm DEC 1-3 becomes the new 50-50 low it COULD allow the above scenario to occur. the D 8-10 500mb average does indicate that to a degree.

Below is what a STRONGLY negative NAO looks like from DEC 26 2000.

12z DEC 26 2000

[wxguy25]

http://meteocentre.com/models/ukmet_ame ... _panel.gif

12z UKMET supports 12z ECMWF. SLP tracks from AR to S NE WED and THU.

this would be a SN situation for C MO, N MO, N IL, MI, NW OH, N NY, VT, NH, ME. Wraparound snows could reach areas of PA, NY, and the rest of SNE depending on how much deepening of the SLP occurs.

Big cities w/ the exception of Boston and perhaps NYC...its ALL RAIN.

[Stormsfury]

The block is definitely there ... and the wild card NOW becomes 93L (Invest) ... a well-defined and cut off gale center, which has about a 24-36 hour window to potentially acquire subtropical characteristics. Irregardless, a pronounced blocking signature in the ATL ...

The 3 day avg. from the ECMWF continues to show encouraging signs, including signs of the Aleutian Low trying to push into place, SE ridge is squashed flat, some signs of some blocking in the C PAC with an elongated and positively tilted trough under another ridge NNE of HI (which seems a little suspicious, but COULD be interesting down the road). But right now, we're stuck/dealing with a +WPO pattern ...

SF

[Wnghs2007]

EEK...What I meant was the high....Up In the Artic Circle that keeps the PV on this side of the pole. Its sort of gone. If I find anything close to that high its north of Alaska. But heck Im an amature so what would I know.

[Stormsfury]

EEK...What I meant was the high....Up In the Artic Circle that keeps the PV on this side of the pole. Its sort of gone. If I find anything close to that high its north of Alaska. But heck Im an amature so what would I know.

Ah ok ... the high at the NP with 513dm heights isn't exactly that high ...

SF

[Wnghs2007]

This is what I meant....Well this is not as great as A high as iit was a few runs ago but it was still there.



THEN...Its all gone...Basically



There you go.

[wxguy25]

The block is definitely there ... and the wild card NOW becomes 93L (Invest) ... a well-defined and cut off gale center, which has about a 24-36 hour window to potentially acquire subtropical characteristics. Irregardless, a pronounced blocking signature in the ATL ...

The 3 day avg. from the ECMWF continues to show encouraging signs, including signs of the Aleutian Low trying to push into place, SE ridge is squashed flat, some signs of some blocking in the C PAC with an elongated and positively tilted trough under another ridge NNE of HI (which seems a little suspicious, but COULD be interesting down the road). But right now, we're stuck/dealing with a +WPO pattern ...

SF

OLGA in 2001 comes to mind here which developed from an upper low near 30N/50W between NOV 20 and NOV 30.

http://www.weather.unisys.com/hurricane ... /track.gif

The strong ridge that developed the northeast of it would eventually be mechanism which sent the NAO negative and of course led to the displacement of the vortex and arctic outbreak of late DEC and early JAN 2001-02.

Otherwise as we all know that winter bit the dust. And the good news is that MOST of us will not see another winter like that in our lifetimes.

I agree the SE ridge is gone but You DON’T get a SE ridge muchless a pronounced one if A) the PV is displaced, B) there is a 50-50 low and strong blocking.

You could be right about the sub-tropical tough, and the ridge developing to the NW of it. If the energy cuts off, then we COULD see a rex block develop off the west coast.

As far as the pacific goes, the North pacific low will be displaced west of the Aleutian low position b/c the cool pool is developing further back to the west between the tip of the Aleutians westward to JAPAN and the Kamchata Peninsula while the warm pool is reconfigurating over the western GOA.

As long as that’s the case the North PAC low will be located west of the Aleutian low position.

https://www.fnmoc.navy.mil/products/NCO ... nomaly.gif

This would mean that a predominant RNA pattern is the order.

[Wnghs2007]

https://www.fnmoc.navy.mil/products/NCO ... nomaly.gif

This would mean that a predominant RNA pattern is the order.

Hey man...To see a POSITIVE PNA pattern coming up on the map of above wouldnt we want to see some very WARM like dark red anomilies over the NE Pacific in the GOA. I just am trying to remember.

[wxguy25]

No. Its more significant to see a cold pool near the Aleutian islands and a warm pool in the GOA surrounding the NW coast of North America. e.g,

https://www.fnmoc.navy.mil/products/OTI ... nomaly.gif

[wxguy25]

We’re not at the point yet where we can get a sustained +PNA pattern, but its getting close. We can expect to see more variability in the PNA index vs. the persistent RNA pattern we were seeing.