A meteorologist just posted this... as you can see, they have to ask questions too. He's referring to this height anomalies chart (pressures): http://www.daculaweather.com/images/2013_01/f384.gif

"Usually by days 10-16 or sometimes sooner, all the anomalies get smeared out by model ensemble spread. I have been watching these charts for years and can't recall such a persistent cold trough as I have seen lately. It could just be the GFS ensembles going extreme but run after run after run??? Is it onto something for the first week of February??? "

1pm temps around the country. Notice the cold air pooled just north of the border
http://www.daculaweather.com/4_ui_us_st_new.php

Atlanta NWS was saying this in the afternoon discussion:
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MOST OF THE LONG TERM PERIOD SHOULD BE QUIET AS THE SOUTHEAST
REMAINS ON ANTICYCLONIC SHEAR SIDE OF JET WRAPPING AROUND BROAD
LONG WAVE TROUGH COVERING THE ERN 2/3RDS OF THE CONUS. DRY COLD
FRONT SHOULD PUSH THROUGH THE STATE TUES WITH COOLER AND MUCH
DRIER AIRMASS...RH MAY DROP TO 15-20PCT TUES AFTERNOON.

DRY PATTERN WILL CONTINUE THROUGH FRIDAY WHEN LARGE SHORTWAVE
TROUGH WILL APPROACH THE AREA. 12Z GFS ABOUT 12HRS FASTER THAN 00Z ECMWF WITH THIS SYSTEM...BUT OTHERWISE IN GOOD AGREEMENT ON
OVERALL STRENGTH AND ORIENTATION.

OTHER CONCERN WITH THIS SYSTEM IS THREAT FOR WINTER PRECIP AS GFS SHOWS SECONDARY SHORT WAVE DIVES IN BEHIND MAIN SYSTEM AND NEARLY CLOSES OFF UPPER LOW OVER FAR NORTH GA 12Z SAT.

ECMWF SLIGHTLY DIFFERENT ON SECOND WAVE BUT SIMILAR PATTERN WITH DEEPER TROUGH AND COLDER AIR. HAVE INTRODUCED CHC OF RAIN/SNOW OR ALL SNOW SHOWERS TO FAR NORTHERN COUNTIES FOR FRI NIGHT. REST OF FCST LOOKS GOOD.

SNELSON

But they were calling for 3-5" Thursday, so they've lost a lot of credibility with me.

Here's a write up they did about the last event. Explains a little about what happened.
http://www.srh.noaa.gov/ffc/?n=rainsnow011813

Once thing that was ot entirely correct in their story was the fact that the models were all pretty unaminous in showing a "hole" of no snow over northeast Georgia/NW South Carolina. Our main hope was dynamically created snow as the low passed us overhead. Some people that were fortunate enough to experience some of the thundersnow, reported snow flakes as big as cotton balls.

Has anyone here experienced thundersnow? In case you're asking what in the world is thundersnow, it's simple a thunderstorm with snow instead of rain. It has to be one of the most incredible weather phenomena I've ever experienced. When there is lightening, the whole sky takes on an errie glow and if the snow is coming down hard enough, the thunder is very muted. In a good thundersnowstorm, it's just like a mini blizzard with snow coming down so hard you can hardly see.

Does anyone remember the Storm of The Century in 1993 here? We had thundersnow then. http://en.wikipedia.org/wiki/1993_Storm_of_the_Century

Once thing that was ot entirely correct in their story was the fact that the models were all pretty unaminous in showing a "hole" of no snow over northeast Georgia/NW South Carolina. Our main hope was dynamically created snow as the low passed us overhead.

Has anyone here experienced thundersnow? In case you're asking what in the world is thundersnow, it's simple a thunderstorm with snow instead of rain. It has to be one of the most incredible weather phenomena I've ever experienced. When there is lightning, the whole sky takes on an eerie glow and if the snow is coming down hard enough, the thunder is very muted. In a good thundersnowstorm, it's just like a mini blizzard with snow coming down so hard you can hardly see. Some people that were fortunate enough to experience some of the thundersnow the other day, reported snow flakes as big as cotton balls.

Does anyone remember the Storm of The Century in 1993 here? We had thundersnow then. http://en.wikipedia.org/wiki/1993_Storm_of_the_Century

-17ºF this morning in International Falls MN this morning. The arctic air will be working its way south and the leading edge should arrive here tomorrow afternoon. You can view daily weather extremes here: http://www.daculaweather.com/4_world_extremes.php

This map shows surface temperatures that are updated hourly:
http://www.daculaweather.com/4_ui_us_st_new.php

I've been in thundersnow. As a matter of fact, the storm we had in January two years ago produced a little of it. The storm of 1993 had a LOT of it. Lightning popping around our house in Oakwood and snowing so hard you could barely hear the thunder. That storm was kinda scary. If you can send me your email address (send it to my county email), I will send you a picture I think you will like.

Done!

Very interesting HPC Extended forecast discussion from just a little while ago
http://www.daculaweather.com/4_hpc_extended_disco.php

They have sent several NOAA flights over the northern Pacific over the last few days and are sending another one today, to sample the upstream atmosphere by dropping radiosondes. They normally do this in hurricanes or ahead of hurricanes to help them better establish strength and track of a particular system. I asked a meteorologist specifically what they were looking for, this was his thought:

"The uncertainty is in the Day 6 and beyond time frame. The main concerns are the short waves crossing the Pacific and the interaction with the stalled Arctic boundary. Also of concern is the Kelvin Wave as well as the increased activity should the MJO finally move into an 8/1 scenario. That would tend to favor a stormy pattern across the West/Great Basin and on ENE as a noisy STJ become established. What we'll need to watch is the January 28th, +/- a couple of day’s time frame. There are indications that a potent system will develop across the Southern Rockies/Southern Plains as the Western Ridge breaks down and the EPO/PNA regime become more favorable for Southern tracking storm as we enter the late January/early February time frame. That said there remain a great deal of uncertainty as to just exactly how the pattern evolve and who/where will benefit from the upcoming pattern, IMO."

Upstream from us at Birmingham
http://www.daculaweather.com/4_afd_bmx.php

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
300 PM CST SUN JAN 20 2013

.DISCUSSION...
THE MODELS STILL HAVE THAT SNOW SHOWER "LOOK" TO THEM FRIDAY
NIGHT...STRONG COLD ADVECTION AT THE SURFACE AND THE TEETH OF THE
UPPER VORT MAX MOVING THROUGH. I'VE KEPT THAT MENTION IN THE
FORECAST...ALTHOUGH CONFIDENCE OF MEASURABLE PRECIP IS QUITE LOW.
WILL CONTINUE TO MONITOR. GIVEN THE HIGHER CONFIDENCE OF COLDER
TEMPS ON SATURDAY...I HAVE GONE SIGNIFICANTLY BELOW THE MAVMOS
GUIDANCE (WHICH HAS A BIG CLIMO COMPONENT IN IT) DURING THE DAY ON
SATURDAY.

Steve, in all seriousness do sites like weather.com and weather underground not look at the same stuff you do. Because they are all calling for mostly mid 60's over the next ten days---nothing like what I read above. Who wants a snowstorm today and 60's tomorrow anyway. That's just nasty.

I know Weather.com uses the GFS forecast and all of them go with climo much past 5 days, they figure they can't be too far wrong if they do. Even the NWS does the same thing.

Pitiful isn't it... ;-)

Oh... weather.com bought wunderground.com

See the image on this page:
http://www.daculaweather.com/4_forecast_gwinnett.php

I believe we'll be a little bit below those temps, they still blend climo in.

http://www.daculawea...ended_disco.php

I'm liking the sound of this more and more...a few excerpts:

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
407 AM EST MON JAN 21 2013

VALID 12Z THU JAN 24 2013 - 12Z MON JAN 28 2013

GIVEN THE COLD ANTECEDENT CONDITIONS...THIS
SYSTEM WILL LIKELY RESULT IN CONSIDERABLE ICE/SNOW AMOUNTS ALONG
AND NEAR THE TRACK OF THE LOW.

...UPDATE...

ALL PARAMETERS FOR DAYS 3 AND 4 WERE UPDATED TO REFLECT A 00Z
UKMET/00Z GEFS MEAN COMPROMISE...
WHICH IS MUCH SLOWER AND SOUTHWARD WITH THE LOW TRACK FROM THE
SOUTHERN PLAINS TOWARD THE OHIO VALLEY.

I'm a little concerned about the lack of blocking so far. The west block keeps getting crashed by Pacific lows, the NAO block is too far north and not doing us any good at all, and this keeps the really cold air from pushing any further south. There is a very tight gradient with the very cold temperatures to the north of it, and to the south... well, that's us.

What we'll get starting this afternoon will bring us back to slightly below normal for a day or two with a quick warm-up before the next system arrives toward the end of the week. This still falls in line with the timeline in my original post of stormy weather for the 24-25th (maybe 26th) with colder air behind that.

Great article about MJO's or the Madden-Julian oscillation. As we head toward Phase 8 (which is favorable for cold here) and hopefully colder weather, this article by Paul Roundy, a professor of Meteorology, explains the MJO and how it effects our weather. Here's an image of the temp anomalies in the various phases: http://www.daculaweather.com/images/MJOPhasesJFM.jpg

http://blog.timesunion.com/weather/the-tropics-affect-our-weather-madden-julian-oscillation/1257/

http://www.daculaweather.com/4_mjo_phase_forecast.php

I like watching this water vapor loop of our side of the Northern Hemisphere. It helps to see the global weather patterns and the flow of the systems. Notice the weak western ridge and how it's causing the flow to ride over the top... and that is good, although it needs to be stronger. In the east, you can see how the systems that exit the US just ride straight out to sea. We need to see a ridge out there (the NAO block) instead. That would force the flow to buckle and cause it to dive further south our direction.

http://www.daculaweather.com/4_nh_wv_loop.php

Latest AFD regarding Friday and the weekend. Trending colder with a slight chance of some wrap around snow.

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
SOMEWHAT MORE ACTIVE LONG TERM PATTERN DEVELOPING. NW FLOW PATTERN WILL TRANSITION TO ZONAL FLOW BY THURS. SHORTWAVE PROGGED TO DROP SE INTO THE MIDWEST STATES FRI WITH FRONT TRAILING INTO MID MS VALLEY. THIS FRONT AND ANTECEDENT WARM/MOIST ADVECTION SHOULD BE SUFFICIENT FOR WIDESPREAD LIGHT-MDT RAIN EVENT. APPEARS INSTABILITY WILL NOT BE ENOUGH FOR EVEN ELEVATED CONVECTION SO HAVE KEPT TSRA OUT OF FCST.

STRONG ARCTIC HIGH PUSHING IN BEHIND FRONT. ALTHOUGH CLIMATOLOGICALLY RARE TO SEE SNOW WITH NW FLOW ALOFT BEHIND FRONT...COULD SEE SOME FLURRIES OR LIGHT SNOW SHOWERS BEFORE PRECIP ENDS...ESP IF UPPER LOW COULD BECOME MORE CLOSED OFF THAN CURRENT MODEL RUNS SHOWING. AS IT STANDS NOW BASED ON 12Z GFS/12Z ECMWF...WILL PROBABLY NOT SEE ANY SNOW BUT HAVE ADDED SLT CHC OF RAIN OR SNOW SHOWERS TO FCST TO ACCOUNT FOR UNCERTAINTY IN POSSIBLE OCCLUSION OR MORE INTENSE ARCTIC
AIR IN LATER MODEL RUNS.

INTENSITY OF COLD AIR COULD BE QUITE STRONG. 12Z ECMWF HAS TAKEN A TURN FOR THE COLDER COMPARED WITH 00Z RUN AND 00Z ECMWF MOS WAS ALREADY QUITE A BIT COLDER THAN GFS MOS TEMPS. WILL CONTINUE TO MONITOR THIS BUT WOULDNT BE SURPRISED IF TEMPS TREND COOLER WITH SUBSEQUENT MODEL FCSTS.

Weather Underground is calling for SEVENTY TWO next Tuesday and Wednesday. If that pans out, I'm putting a tiller to the garden and getting ready for an early start this year. Ain't missing out like last year.

Birmingham is having a hard time believing temperatures that are 6 standard deviations below normal...

THE MOST PUZZLING PART OF THIS FORECAST PACKAGE...AS IT HAS BEEN FOR
THE LAST FEW DAYS...IS THE TEMPERATURE GUIDANCE OVER THE NEXT 5-7
DAYS. MODELS ARE STRUGGLING MIGHTILY WITH HOW COLD IT WILL BE AT
NIGHT AND HOW WARM IT MAY GET EACH DAY. I DON'T THINK I'VE EVER SEEN
A 6 STD IN THE ENSEMBLE GUIDANCE...AND COUPLE THAT WITH A 20 DEGREE
RANGE IN THE GFS ENSEMBLES THURSDAY AND THURSDAY NIGHT...WE COULD
GET THINGS HANDED TO US COME VERIFICATION TIME. WON'T MAKE ANY
MAJOR CHANGES RIGHT NOW AND HOPE FOR SOME BETTER GUIDANCE WITH
UPCOMING MODEL RUNS.

Jan 24 - 25 - Stormy - Coming Friday
Jan 26 - 29 - Cold shot - Saturday 26th
Jan 28 - 29 - Warm-up = Tommy tills his garden
Jan 31 - 02 - Reinforcing good cold shot -
Feb 02 - 04 - Warm-up = Tommy plants his garden
Feb 05 - 07 - Stormy/ good cold shot
Feb 07 - 11 - Stormy/ cold shot = Tommy's garden freezes twice :-)

Could be a little warm up in between those two Jan cold shots but I highly doubt 70's then. We'l see who's correct! :-)

From a local meteorologist this morning:

6z GFS has a nice light freezing rain/sleet event across much of north GA for at least the first half of Friday. The sounding for Dahlonega at 1pm Friday which shows temps in the 20's. Backing it up a bit to the 1am Friday sounding shows solid below freezing wetbulb column before the precip arrives. So IMHO that could equal a brief start as sleet/snow before the mid levels warm to change all precip to sleet/freezing rain.

Something to watch for sure.

From another...

The southern extent of the ZR keeps getting further south in GA. The 18z 1/21 GFS had gotten down to Cumming/Gainseville. The 0z 1/22 GFS had reached all of the way down to Marietta with a tiny amount (~.01") The 1/22 6z GFS is all of the way down to the southside of Atlanta at the airport with a tiny amount while it gives Marietta nearly .10". It is mainly about the colder trends right now as the models play catch-up with the intensity of the cold, dry air that will be in place initially. All of this is being shown without the aid of cold easterly winds. The modeled winds are still SE and, yet, there is some ZR that is trending further south. Imagine how much more significant this could get if the runs start showing ZR locking east winds as well as heavier precip. With the potential event still 78 hours out, there's still plenty of time for this to evolve. Analogs and climo are keeping me on my toes with this threat.

What channel Tommy?

PLEASE don't let them mess with it! :-)

Oooooooo.... really good news. If you like cold. I wish I could bold in the comments...

PROGNOSTIC DISCUSSION FOR 8 TO 14 DAY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST TUE JANUARY 22 2013

THE ENSEMBLE MEANS AND DETERMINISTIC RUNS FOR WEEK 2 HAVE COME INTO BETTER AGREEMENT OVER THE PACIFIC-NORTH AMERICA DOMAIN, ESPECIALLY IN THE VICINITY OF ALASKA. THE GFS, EUROPEAN AND CANADIAN-BASED MODELS ALL AGREE THAT THE EASTERN
PACIFIC RIDGE WILL REACH THE WEST COAST, BUT MORE IMPORTANTLY AMPLIFY ACROSS ALASKA AND MUCH OF THE ARCTIC OCEAN.

HAVING TWO DISTINCT POLAR VORTICES PREDICTED IN THE 500-HPA GEOPOTENTIAL HEIGHT FIELD (ONE CENTERED OVER HUDSON BAY, AND THE OTHER CENTERED ALONG THE NORTHERN COAST OF RUSSIA), WOULD ENABLE DELIVERY OF BITTERLY COLD ARCTIC AIR FROM NEAR THE NORTH POLE SOUTHWARD ACROSS CENTRAL CANADA AND INTO THE CENTRAL AND EAST-CENTRAL CONUS. ODDS FOR ABOVE-NORMAL TEMPERATURES ARE STILL ENHANCED ACROSS PARTS OF THE SOUTHEAST EARLY IN THIS PERIOD, IN ADVANCE OF THE ANTICIPATED ARCTIC AIR OUTBREAK.

IT IS IMPORTANT TO EMPHASIZE THAT THE EXPECTED SPATIAL EXTENT OF THIS VERY COLD AIR HAS BEEN TEMPERED SOMEWHAT DUE TO DIFFERENCES BETWEEN THE VARIOUS SURFACE TEMPERATURE TOOLS, AND MAY BE FARTHER SOUTH AND EAST THAN WHAT IS CURRENTLY
INDICATED.

Models are still showing some form of wintry precip sometime during the day on Friday. Temperature profiles indicate a sleet/freezing rain type of event. Precip amounts would be light, but .1-.25" of freezing rain would be a nightmare. One met just commented:
"My point is that if there were to be ~0.25" of freezing rain on Friday in much of N GA, it shouldn't be trivialized by any means. That would be a pretty sig. winter storm in its own right and wouldn't have been exceeded in over 7 years in terms of ZR amounts in Atlanta at least."

Nice write up on the Stratospheric Warming http://www.climatecentral.org/news/stratospheric-phenomenon-is-bringing-frigid-cold-to-us-15479

PLEASE READ: http://www.daculaweather.com/4_afd_ffc.php

HPC PROBABILITIES BASED ON
MODEL CONSENSUS SHOWING GREATER THAN 80 PCT PROB OF 0.01 INCH OF
FREEZING RAIN...WITH THE DETERMINISTIC FORECAST SHOWING A SWATH OF
0.10 TO 0.25 INCHES FROM NORTHWEST GA...SOUTH THROUGH THE ATLANTA
METRO EASTWARD ALONG I20 INTO SC. WILL LET LATER SHIFTS HONE IN ON
BOTH AMOUNTS AND TIMING AS THE EVENT UNFOLDS.

I'll have a new post about this ice storm later this afternoon. See the image I just uploaded.

Yes! And let me say this... .1 - .25" of ice is serious. With the ground very wet still, trees will come down, power lines will come down... this is potentially a VERY big mess.

I absolutely HATE ice storms. You can't even play in them. At least the roads are too warm to freeze.

Freezing Rain Advisory just issued:

...POTENTIAL FREEZING RAIN EVENT ON FRIDAY...
.A COLD FRONT WILL MOVE THROUGH THE SOUTHEAST ON FRIDAY BRINGING
PRECIPITATION TO THE AREA. COLD AIR AT THE SURFACE...ESPECIALLY
WEDGED ALONG THE NORTH GEORGIA MOUNTAINS...WILL RESULT IN
PRECIPITATION FALLING AS FREEZING RAIN AND SLEET.
...FREEZING RAIN ADVISORY IN EFFECT FROM 6 AM TO 1 PM EST
FRIDAY...
THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A
FREEZING RAIN ADVISORY...WHICH IS IN EFFECT FROM 6 AM TO 1 PM EST
FRIDAY.
* LOCATIONS...PORTIONS OF NORTH GEORGIA...GENERALLY WEST AND SOUTH
OF A LINE ELLIJAY TO CUMMING TO GAINESVILLE. PORTIONS OF CENTRAL
GEORGIA...NORTH OF LINE FROM FRANKLIN TO GRIFFIN TO EATONTON TO
CRAWFORDVILLE.
* HAZARD TYPES...FREEZING RAIN.
* ACCUMULATIONS....LESS THAN A TENTH OF AN INCH OF ICE...BEFORE
THE FREEZING RAIN TURNS TO ALL RAIN AND MELTS.
* TIMING...6 AM TO 1PM EST FRIDAY.
* IMPACTS...ICE WILL CAUSE ROADWAYS AND SIDEWALKS TO BECOME
SLIPPERY...MAKING TRAVEL DANGEROUS ESPECIALLY ON BRIDGES AND
OVERPASSES.
* WINDS...EAST 5 TO 10 MPH WITH GUSTS UP TO 20 MPH.
* TEMPERATURES...AROUND 30 IN THE MORNING WARMING TO AROUND 40 BY
AFTERNOON.
Instructions:
A FREEZING RAIN ADVISORY MEANS THAT PERIODS OF FREEZING RAIN OR
FREEZING DRIZZLE WILL CAUSE TRAVEL
DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS. SLOW DOWN AND USE
CAUTION WHILE DRIVING.