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End of January Winter Weather Possibilities

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3 hours ago, Mountainbuck said:

Excited to see the trend in those 🤪

 

8 minutes ago, matt40 said:

Hoping for some great news on this evening models!

Not much change in the GFS for Monday & still not picking up the 2nd system...at all.

Euro is up next.

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5 minutes ago, stevepolychronopolous said:

 

Not much change in the GFS for Monday & still not picking up the 2nd system...at all.

Euro is up next.

Baby steps in the good direction with the placement of the jet streak for the Tuesday system. Didn’t translate to the surface, but still a positive. 2nd system is there it’s just super suppressed, which is possible with the magnitude of the upcoming arctic outbreak. We won’t talk about the torch that follows for the rest of the run...

Will be surprised if the Euro doesn’t back off a bit from the 12z run.

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The NAM is out of its range at 84 hrs, but for whatever it may be worth it does look a lot better than the GFS. Slower and more similar to the Euro with the placement and angle of the jet streak, which will determine whether we see an ana or kata cold front.

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45 minutes ago, KingOfTheMountains said:

The NAM is out of its range at 84 hrs, but for whatever it may be worth it does look a lot better than the GFS. Slower and more similar to the Euro with the placement and angle of the jet streak, which will determine whether we see an ana or kata cold front.

Can you explain the difference? 

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3 minutes ago, Athens said:

Can you explain the difference? 

Cold fronts generally come in 2 different variations anafronts and katafronts, although in reality most cold fronts are often split with part being ana and part being kata. Katafronts are what we've had over the last week or so. They have most of the precipitation ahead of the cold front. Anafronts are the opposite, they tend to have most of the precip behind the cold front. We need Tuesdays system to be the latter if we want snow. Now there are a few ways to try and spot them, but the method I use is a general rule of thumb that a cold front to the left of the jet streak is ana and to the right is kata.

To help visualize this I'll show 2 different examples. First is a map of the jet stream for this past Wednesday's storm that we know was rain with a few flurries behind, so kata. Notice how we are to the right of the strong streak in the jet stream.

1423149745_namconus_uv250_us_1(1).thumb.png.a63677b835d6181d8437418828ace8e7.png

And then the jet streak from the 12z euro. Notice how N GA is to the left this time, indicating that it should be mostly an anafront. 1938537274_download(6).thumb.png.4ed45a996d7b717b3e412abb7e004870.png

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Small scale back from 12z on the euro especially for the far north counties, but nothing too significant given how far out we still are. So for now, the model wars will continue. Both scenarios could happen. It may be last minute before having much confidence. What happens with the system along the east coast Sun./Mon. will have impacts on our system. 

0z GFS vs 0z Euro

246061545_download(8).thumb.png.ef1e72a815146498a4e6a4a6caa64d64.png136750784_download(9).thumb.png.0219076e739a5060e1b9f2749a000d44.png

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Ensemble support continues to go the wrong direction though. Without ensembles on board I will not be confident in this event. They were the first to abandon us with the last “threat” and were right to do so.

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Might get a dusting tonight. That is a pretty potent little disturbance swinging through 

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Wow I can really feel the confidence increasing for our storm 😂😂😂🤥🤥🤥 oh this winter is about to be tossed in the garbage can as far as I am concerned STINKS

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Seems they are more concerned with blackice on Wednesday morning, than snow on Tuesday. 😥🤔😭😭

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Good morning! First, a word from our sponsor. 

Quote

Primary concern in the extended forecast period continues to be the
wintry precipitation Tuesday. Still significant differences in the
medium-range models concerning mainly the amounts of precipitation
and the timing/duration of the mixing/change-over from liquid to
frozen precipitation. GFS and Canadian models continue to be faster
and noticeably lower in QPF than the ECMWF. This appears to be due
to the stronger, slower and more southerly track of the short wave in
the European solution. I have stuck with a model blend for now
(namely the NBM for most parameters and WPC QPF) with precipitation
type driven by a non-diurnal temperature trend during the day
Tuesday. This yields a potential for advisory-level or higher
snowfall amounts across the higher elevations of the far north.
Otherwise, only trace amounts are generated across north Georgia,

including into the northern and western metro Atlanta area. No
accumulations expected across central Georgia. Confidence that we
will see some kind of rain/snow mix across much of north Georgia is
fairly high, confidence on accumulations remains low at this time.

Cold and dry air moves across the forecast area from west to east by
late in the day with only lingering light rain in eastern portions of
the forecast area into the early evening. Wouldn't be surprised to
see a few areas with a light rain/snow mix into central Georgia late
in the afternoon/early in the evening, but no accumulations across
that area.

With that being said, the Euro has been the most consistent in what it's showing, so I'm going with that solution right now. I believe the Gulf wave will be stronger based on persistence as we haven't seen weak Gulf waves at all this winter.  Here's what I think will happen.

Snap346062350-26.jpg.1160becb042ca741740c224110ed98f5.jpg

This has great ensemble support right now and it seems to be getting stronger. Below is the ensemble mean.

Snap346062351-26.jpg.7d2ab696c9d3927093a63b33ffd808d9.jpg

 

So that is my first guess on what might happen. Again, I don't make the forecast, that's the job of the National Weather Service so take this with a HUGE grain of salt. No wait.... salt melts ice and snow. Take it with an ice cube. ❄️

 

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18 minutes ago, NorthGeorgiaWX said:

Good morning! First, a word from our sponsor. 

With that being said, the Euro has been the most consistent in what it's showing, so I'm going with that solution right now. I believe the Gulf wave will be stronger based on persistence as we haven't seen weak Gulf waves at all this winter.  Here's what I think will happen.

Snap346062350-26.jpg.1160becb042ca741740c224110ed98f5.jpg

This has great ensemble support right now and it seems to be getting stronger. Below is the ensemble mean.

Snap346062351-26.jpg.7d2ab696c9d3927093a63b33ffd808d9.jpg

 

So that is my first guess on what might happen. Again, I don't make the forecast, that's the job of the National Weather Service so take this with a HUGE grain of salt. No wait.... salt melts ice and snow. Take it with an ice cube. ❄️

 

They seem timid. 

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Why forecasts beyond 2 days out change A LOT 

Ok…I’ve been trolling the local ATL weather personalities Facebook pages and have seen all sorts of confidence of what is GOING TO happen Tuesday.  This is why I mention stuff and don’t hype it up.  The area in the circle is the upper level piece of energy that will be responsible for whatever happens on Tuesday.  As you can see it’s located in the Gulf of Alaska.  Any area that is not over land is data sparce regarding actual data sampling of the atmosphere.  Basically what that means is the PREDICTED event on Tuesday is based on computer models that have pieces of energy over areas that are not sampled to its maximum.  Our piece of energy will not be over land until Sunday  when it will be sampled properly.  Often we see decent shift up until 2 days out and this is the reason.  So anyone saying that their confidence is growing is basing that on energy that is minimally sampled.  Personally I think the best course of action is to mention the potential and wait until maximum data is available before making any sort of irrational posts or predictions.  More often than not this ends up being the best method.

Rant over.

Jason 

You can also follow me on Instagram @dahlonegaweather
 
#gawx #weather #georgia #dahlonega

 

Jason is always the voice of reason for the Dahlonega area!!

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13 minutes ago, Dahlonegawinter said:

Why forecasts beyond 2 days out change A LOT 

Ok…I’ve been trolling the local ATL weather personalities Facebook pages and have seen all sorts of confidence of what is GOING TO happen Tuesday.  This is why I mention stuff and don’t hype it up.  The area in the circle is the upper level piece of energy that will be responsible for whatever happens on Tuesday.  As you can see it’s located in the Gulf of Alaska.  Any area that is not over land is data sparce regarding actual data sampling of the atmosphere.  Basically what that means is the PREDICTED event on Tuesday is based on computer models that have pieces of energy over areas that are not sampled to its maximum.  Our piece of energy will not be over land until Sunday  when it will be sampled properly.  Often we see decent shift up until 2 days out and this is the reason.  So anyone saying that their confidence is growing is basing that on energy that is minimally sampled.  Personally I think the best course of action is to mention the potential and wait until maximum data is available before making any sort of irrational posts or predictions.  More often than not this ends up being the best method.

Rant over.

Jason 

You can also follow me on Instagram @dahlonegaweather
 
#gawx #weather #georgia #dahlonega

 

Jason is always the voice of reason for the Dahlonega area!!

That's why I say what I posted is a guess simply based on what I know right now. We have days of changes left to go. 😉

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NWS Huntsville

Quote

Although temporal differences remain among the latest suite of global models, a
consensus of the guidance suggests that a powerful arctic cold front
trailing southwestward from the surface low will enter northwest AL
at some point during the mid/late evening hours on Monday and push
steadily southeastward through the entire CWFA by 9-10Z. It still
appears as if prefrontal shower activity will increase as the front
intercepts a plume of deeper moisture across our region. However, of
more concern is the potential for postfrontal precipitation, which
could occur in a fairly wide band given strength of lift downstream
from the mid-level trough axis. The precipitation will initially
transition to a mixture of freezing rain/sleet as temperatures
drop immediately in the wake of the front, but should eventually
transition entirely to snow as temps fall below freezing through the
depth of the vertical column. At this point, we suspect most
locations could receive between 1-2 inches of snow, with up to one

hundredth of an inch of ice accumulation in a few spots. Even with
clearing skies, strong advection of arctic air into the region will
ensure that daytime max temps stay around 30 degrees or lower for
most of the region.

 

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1 minute ago, Armystrong88 said:

So basically nothing for Athens and Gainesville?

It's really hard to say right now. Gainesville stands a better chance at the moment.

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Marginal systems are always harder to predict. This could go either way in terms of precip amounts, and the other concern is how quickly the cold air moves in, in relation to the timing of the precip.

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Keep in mind, it doesn't take a lot of snow to bring us to a stand still. Just look at "Snow Jam 2" and you can see the results. That system was overrunning moisture from a Gulf wave, but we did have some cold air in place ahead of time. Snow Jam 2 reminds me more of what could occur around the 2nd. 

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The cold is starting to push...

Quote

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
557 AM CST SAT JAN 26 2019

...NEW RECORD LOW MINIMUM TEMPERATURE SET AT MADISON WI...

A RECORD LOW MINIMUM TEMPERATURE OF -23 DEGREES WAS SET AT
MADISON WI THIS MORNING...SATURDAY JANUARY 26 2019. THIS BREAKS THE
PREVIOUS RECORD OF -21 DEGREES SET IN 1963.

 

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NWS Birmingham is leaning toward the Euro as well. They always have very good AFD's

These are located at the menu at the top of the page. http://wx.northgeorgiawx.com/afd_bmx2.html/

Quote

A deep longwave trough will be in place Monday night with upstream
vorticity maxima digging toward Alabama. A cold airmass will be
racing southward across the Plains and Midwest with a tightening
temperature gradient along an approaching cold front. The front
should largely be void of precipitation at 6PM Monday, but west-
southwest 850-500mb flow should result in quality moisture
advection. A sharpening shortwave and the nose of an approaching
upper-level jet should induce isentropic lift and 850-500mb
frotogenesis, causing post-frontal precipitation to break out to

our west. Operational and ensemble model guidance remain in good
agreement with this scenario which may feature a rapid transition
from rain to snow on Tuesday morning as the front sweeps through.
Between the GFS and ECMWF/NAM, there are some key differences with
the handling of the shortwave and strength of the cold airmass. At
face value, the ECMWF/NAM solution would yield a high impact for
areas near and north of I-20, due to the potential for convective

snow and temperatures falling into the 20s. The GFS appears
flatter with the trough and warmer, with less overlap of cold air
and precipitation. My hunch is that the GFS is a little too flat,
and our forecast will lean toward the more bullish ECMWF/NAM idea.
Snowfall amounts up to 1.5 inches appear possible near and north
of I-20 with amounts dropping off quickly to the south and east.

Higher amounts cannot be ruled out with future updates. Though
amounts are not expected to be particularly impressive, impacts
could be relatively high if temperatures fall below freezing
before the snow ends.

 

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