Wintry 1/7/17-1/10/17 Winter Storm

[Flurry]

What is everyone's gut say for the next GFS?

at this point it does not matter. We have huge 00z runs tonight . Need see some improvement

Sent from my SM-G900V using Tapatalk

Still learning. Why are 00z runs so important?

they have the new upper air data ingested . I believe 18z has some but not the full set like the 00z runs

Sent from my SM-G900V using Tapatalk

The new data is ingested and then burped back up in the form of new model runs...LOL 

 

[Arcc]

If the precip is there, the NAM would be a good sleet producer Deep South. Atleast the cold air is there.

 

[accu35]

NWS bham

Sent from my SM-G900V using Tapatalk

Sweet

 

[richardjacks]

the 18z NAM has that look on he precip shield I have seen many times...a sharp cutoff on the northern extent as it fills to the west then another area moves south cold air aloft sinks in....when in reality it winds up being all one area. Also the start time for Alabama is looking a little earlier than the GFS.

 

[SnowHusky]

See, even the NAM agrees that the low won't go that far south like the GFS is showing...good Lord that GFS model needs help sometimes lol

 

[scott36093]

From BMX...

Models are now in much better agreement with the handling of a
portion of the positively-tilted trough left behind over Oregon
as it heads toward the Southern Plains on Friday. As an Arctic
airmass continues to press southward, the Plains shortwave may
induce a Gulf low with isentropic lift spreading over the region.
With the support of all the global models and many ensemble
members, this forecast update features the first aggressive step
toward a possible high-impact winter storm on Friday into early
Saturday. The strength of the airmass moving southward in advance
of the storm system suggests temperatures could fall well below
freezing during the event which would lead to higher than normal
impacts. Those details will need to be refined in later updates.
The HWO will be updated to include a low confidence chance of
accumulating sleet and snow. Confidence will be raised if models
continue on course.

 

[MBell]

NWS Peachtree City raised the POPS for my area to 50% for both Friday night and Saturday.  Currently calling for a RN/SN mix with a low of 33 Friday night.   That's certainly putting more weight in the GFS camp. Here's their long term discussion for the weekend storm:

.LONG TERM /Thursday through Tuesday/...
Long term forecast largely overshadowed with winter weather
potential for late Friday into Saturday. As previously mentioned,
many contributing factors must align for accumulations to occur,
but models seem to be coming into better alignment with the
potential for accumulations. Winter precip looks to begin Friday
evening (well after school release time), and continue into the
overnight period. Have opted to increase pops for the 00z- 18z
period Saturday, and with model temperatures cooler than
previously forecast, this spreads snow chances farther south and
east with this forecast package. For now, given the uncertainty
with the placement of the moisture axis and the timing of the cold
air into the state, have opted to not include accumulations at
this time. Several ensemble model members are suggesting a couple
inches of snow, but others are going with no accumulations at all.
As far as the more mainstream deterministic models, the CMC has
the moisture axis farther north, across the Atlanta metro area and
northward, with the better chances across the far northern metro
counties. The GFS suggests accumulations are possible across the
Atlanta metro, but keeps the best axis south of the southernmost
metro counties. For the ECMWF, the contributing ingredients do
not appear to line up to promote snowfall accumulations.
Confidence in the forecast is increasing as the latest model runs
(and run- to- run solutions) seem to converge to a similar
solution, and expect this to continue into into late week.

After the winter system moves out of the area, temperatures remain
chilly, and any accumulations would likely stick around into late
weekend.

And what area would that be?  I am showing 26 for my low Friday Night with Snow.

 

[Arcc]

Another observation. The NAM would act much more like a overrunning threat than a true Miller A. Your precip is gonna come from the moist SW flow than the wimpy slp in the gulf.

 

[richardjacks]

While the 18z nam shows just about a perfect storm strack for I-20, it is hour 84 on the NAM... not the best track record.

 

[richardjacks]

Another observation. The NAM would act much more like a overrunning threat than a true Miller A. Your precip is gonna come from the moist SW flow than the wimpy slp in the gulf.

Which is another reason why the precip is prob underdone.

 

[Arcc]

Another observation. The NAM would act much more like a overrunning threat than a true Miller A. Your precip is gonna come from the moist SW flow than the wimpy slp in the gulf.

Which is another reason why the precip is prob underdone.

Yep really getting a Snowjam vibe from the NAM.

 

[ATLwxfan]

Henry Margusity is poo pooing the snow chances. Thinks things shift north to the Tennessee valley. That guy is always wrong so we are in good shape!


Sent from my iPhone using Tapatalk

 

[whizrtr]

From BMX...

Models are now in much better agreement with the handling of a
portion of the positively-tilted trough left behind over Oregon
as it heads toward the Southern Plains on Friday. As an Arctic
airmass continues to press southward, the Plains shortwave may
induce a Gulf low with isentropic lift spreading over the region.
With the support of all the global models and many ensemble
members, this forecast update features the first aggressive step
toward a possible high-impact winter storm on Friday into early
Saturday. The strength of the airmass moving southward in advance
of the storm system suggests temperatures could fall well below
freezing during the event which would lead to higher than normal
impacts. Those details will need to be refined in later updates.
The HWO will be updated to include a low confidence chance of
accumulating sleet and snow. Confidence will be raised if models
continue on course.

Wow. BMX is getting on board. Has Matt joined this forum yet?

 

[deltadog03]

Here is a good look on how the energy *IMHO* is actually trending toward the GFS.....Look how much less interaction and how the 18z NAM is further south with energy vs like the euro....

12z NAM

18z NAM

I know its the silly NAM, and at HR84 for that matter, but I honestly feel like the euro is the outlier here...I really do.

 

[Flo]

Shawn and anyone else involved, I just want to thank you for creating a place for people not in North Carolina to follow winter weather.

 

[Stormlover]

Henry Margusity is poo pooing the snow chances. Thinks things shift north to the Tennessee valley. That guy is always wrong so we are in good shape! j  Go Henry!


Sent from my iPhone using Tapatalk

 

[Flo]

What is the difference in all the models? Where do they get their info that makes them flip and flop?

 

[richardjacks]

From BMX...

Models are now in much better agreement with the handling of a
portion of the positively-tilted trough left behind over Oregon
as it heads toward the Southern Plains on Friday. As an Arctic
airmass continues to press southward, the Plains shortwave may
induce a Gulf low with isentropic lift spreading over the region.
With the support of all the global models and many ensemble
members, this forecast update features the first aggressive step
toward a possible high-impact winter storm on Friday into early
Saturday. The strength of the airmass moving southward in advance
of the storm system suggests temperatures could fall well below
freezing during the event which would lead to higher than normal
impacts. Those details will need to be refined in later updates.
The HWO will be updated to include a low confidence chance of
accumulating sleet and snow. Confidence will be raised if models
continue on course.

Wow. BMX is getting on board. Has Matt joined this forum yet?

The was this morning's disco

 

[GaWx]

Whereas surface pressures over Maryland (for example) when the surface low is in the NE Gulf are up near 1032 mb on the 12Z GFS, near 1030 mb on the 12Z JMA, and near 1028 mb on the 18Z NAM, they are a measly 1020 mb on the 12Z Euro. It would be better if those pressures for low level cold air purposes were higher than 1020 mb.

 

[whizrtr]

From BMX...

Models are now in much better agreement with the handling of a
portion of the positively-tilted trough left behind over Oregon
as it heads toward the Southern Plains on Friday. As an Arctic
airmass continues to press southward, the Plains shortwave may
induce a Gulf low with isentropic lift spreading over the region.
With the support of all the global models and many ensemble
members, this forecast update features the first aggressive step
toward a possible high-impact winter storm on Friday into early
Saturday. The strength of the airmass moving southward in advance
of the storm system suggests temperatures could fall well below
freezing during the event which would lead to higher than normal
impacts. Those details will need to be refined in later updates.
The HWO will be updated to include a low confidence chance of
accumulating sleet and snow. Confidence will be raised if models
continue on course.

Wow. BMX is getting on board. Has Matt joined this forum yet?

The was this morning's disco

Ah, will be interesting to see if they shift given the 12z Euro