January 20-21 Snow/Ice Threat

[Curt]

Sunday 1/16 12z EURO

Memphis .54 in qpf...starts as freezing rain and goes to sleet and snow. About half looks to be freezing rain to me. The rest is 2-3 inches of sleet and snow.

Nashville-.27 qpf... all snow probably 2-4 inches

Chatt- close to .70 qpf, rain ending as freezing rain or sleet

Knoxville .58 qpf...probably half as rain and half as snow

For Memphis posters...although its still a ways out...the precip types are scattered from north to south in the metro...more snow north, more ice south. We have seen that one play out before here.

[Curt]

12 z GFS is catching on to increased qpf, but not the cold as most are rain ending as frozen precip. GFS as usual in this range has been all over the map from snow and little qpf to a tad warmer and rain. Have to give the EURO some credibility here as its been showing the same run now for 2 days.

[tennessee storm09]

this one is shaping up to be a intersting event to me. going to be fun watching the models pregress this week. could be looking at a major winter storm by late next week. seems like most of our good snows seems to start as rain or fz before going over to all snow.

[Matthew]

I want to say this is a great weather forum. ::flag::I appreciate ALL the moderators on here.  Kevin & Eric to mention along with others but not sure of names.  I continue to learn from you ALL.  So I would just like to say THANK YOU!  It is nice to come to a forum to learn and not read bashing most of the time.  Another winter storm threat!  What a winter!  School days are running out quickly and already out for some.  Could be a year where all the days can not be made up.  My brother in law is director in a close school system.  We stay in touch about upcoming witner mischief.  They just had a board meeting yesterday to discuss make up days if needed.  We just spoke and I told him about the upcoming possibilty.  Also hearing and reading another possible winter storm on this ones heels.  Climo for Nashville is most snow occurs late January thru February.  So maybe we are just getting started.

[jmundie]

You can almost bank on there being ice further south and east than models currently showing. They are not good with low level cold pushing under warm air

[Cyclonicjunkie]

HPC guidance

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
145 PM EST SAT JAN 15 2011
 
VALID 12Z TUE JAN 18 2011 - 12Z SAT JAN 22 2011
 

OVERALL MEAN PATTERN OVER CONUS THIS PERIOD WELL AGREED UPON WITH
SHORTWAVE SPEED AND AMPLIFICATION DIFFERENCES ENOUGH TO WARRANT
LOW CONFIDENCE IN DETAILS. THE BUILDING AMPLITUDE OF THE ERN
PACIFIC RIDGE AND INTERIOR SEPERATE ARCTIC STREAM AMD ITS
INTERRACTION BRING THESE PROBLEMS INTO PLAY THROUGH THE PERIOD.
YESTERDAY UKMET AND ECMWF WERE GROUPED TOGETHER WITH STRONGER SRN
STREAM SHORTWAVE ENERGY EARLY IN THE PERIOD ACROSS THE GULFMEX AND
SERN SEABOARD AND WITH A NEXT DIGGING SHORTWAVE DROPPING DOWN
ALONG THE WEST COAST LATER PERIOD. THESE FEATURES ARE MUCH MORE
SMOOTHED OUT BY ALL MODEL AND ENSEMBLE SOLUTIONS TODAY.

ECMWF HAS THE MOST CONSISTENT CONTINUITY BUT WITH A DAMPENING OF
ITS SHORTWAVES FROM PRIOR RUNS. USING A LAGGED AVERAGE FORECAST OF
ITS PAST FOUR RUNS WOULD YIELD A SOLUTION THIS PERIOD CLOSE TO A
BLEND OF THE 00Z OPERATIONAL ECMWF AND THE 00Z ECMWF ENS MEAN.
THIS MAINTAINS MORE SRN STREAM ENERGY THAN THE GFS DAY 5 ONWARD
ACROSS THE GULF COAST AND ERN SEABOARD.

LOW PRESSURE WILL BE DEVELOPING OFF THE SOUTHEAST SEABOARD DAY 3
TUES WITH SOME RAIN THRU THE SOUTHEAST AND MID ATLC REGION WITH
HEAVIER PCPN POTENTIAL ACROSS NEW ENGLAND. WELL AGREED UPON
REINFORCING COLD SURGE WILL SPREAD SWD THRU THE NRN AND CENTRAL
PLAIN AND OFF THE EAST COAST BEHIND THE EXITING LOW.

AMPLIFYING WRN TROF SHOULD BRING DOWN HIGH PRESSURE BOTH EAST AND
WEST OF THE DIVIDE MID WEEK PROVIDING ENOUGH GRADIENT AND PRESSURE
DIFFERENTIAL FOR A WEST COAST OFFSHORE/SANTA ANA EVENT.

AN AREA OF LOW PRESSURE MAY DEVELOP ALONG THE ERN GULF
COAST/SOUTHEAST DAY 5 THURSDAY AND MOVE NEWD UP ALONG OR OFF THE
LOWER MID ATLC COAST. THIS REMAINS UNCERTAIN WITH ONLY 00Z/12Z
ECMWF AND TO SOME DEGREE THE 00Z CMC SUPPORTING MUCH IF ANY
DEVELOPMENT AND WITH LOW ENSEMBLE SUPPORT. HAVE CHOSEN TO USE A
MODIFIED ECMWF TO TAKE THIS SYSTEM NEAR THE NORTHEAST BENCHMARK
ALONG A CLIMO TRACK WITH LOW CONFIDENCE. SECOND FAIRLY WELL AGREED
AMPLITUDE OF THE NRN STREAM INDICATES A SECOND VERY STRONG COLD
SURGE DROPPING THRU THE NRN PLAINS DAY 5 THURSDAY AND DRIVING TO
THE EAST COAST DAY 6 AND 7 FRI/SAT WITH SOME OF THE COLDEST AIR
THIS SEASON AS REFLECTED BY THICKNESS VALUES AND H850 TEMPS.
HIGHER CONFIDENCE IN THE PATTERN BY NEXT WEEKEND AS INDICATED BY
TELECONNECTIONS/FORECAST MJO INDEX ENTERING PHASE 7 AND 8/
POSITIVE PNA AND NEG AO/NAO PATTERNS AND GOOD OPERATIONAL AND
ENSEMBLE AGREEMENT YIELDING A MILD WRN CONUS AND FRIGID EAST.
WIDESPREAD AREAS OF SINGLE DIGIT AND BELOW ZERO LOW TEMPERATURES
CAN BE EXPECTED OVER THE NORTHEASTERN QUARTER OF CONUS NEXT
WEEKEND.
ROSENSTEIN

[dwagner88]

To be honest, I'll be happy to sit this one out. Especially when the p type appears to favor ice vs. snow here. If I miss any more school, I'm gonna have to go later in May. Hope everybody else gets slammed though!

[Woodvegas]

RGEM is headed in the right direction. As of now it would be more of an overrunning event per the ECMWF and Canadian models which could result in FZ for some. The 12Z GFS shows a more deveoped low.

12Z RGEM:
http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

12Z GFS:

[tennessee storm09]

like to share what i have read on some other fourms, fwiw. read were they are sending out more recon planes out to gather more weather data fot this upcoming week time period. thought that was kind of interesting. arreas mentioned were texas, louisiana, arkansas and east oklahoma. very interesting

[ajatwister]

right now it look exactly like the january 2010 event... warm nose and everything. bleh. things will change though. hopefully.

[tennessee storm09]

right now it look exactly like the january 2010 event... warm nose and everything. bleh. things will change though. hopefully.

that turned out to be a heck of a system for me on january 29th. 2010. got right at 10 inches here in jackson.

[Sbeagles]

I'm am away for the weekend so I'm following on my phone. I can't see any models but from reading what you all are are saying it sounds mighty interesting. I'm no where near ready for winter to be over  so bring it on. Good luck with this one everyone and hope for snow not ice.

[jmundie]

right now it look exactly like the january 2010 event... warm nose and everything. bleh. things will change though. hopefully.

This set up is not modeling anything like that event. This is a wave of low pressure riding a cold front. Cold air at the surface will be leaking underneath the precip.

We haven't had one of these in a while.

I think Larry cosgroves map back in the other thread looks like a good forecast

[shooting70]

This set up is not modeling anything like that event. This is a wave of low pressure riding a cold front. Cold air at the surface will be leaking underneath the precip.

We haven't had one of these in a while.

I think Larry cosgroves map back in the other thread looks like a good forecast

Jmundie,i have a few things to ask. Do you think larry cosgrove may shift the track a bit further southward later on?The euro and cmc has the low more over southern mississippi,along with the HPC. To me,the gfs didnt look that good.Low further north and more developed,and if that happened,our area wouldnt see much winter wx,except maybe at the tail end,like curt was alluding too. The other thing i wanted to ask is why do you think the hpc is kinda in dissaray about this storm?Whats throwing them off now.They mentioned the models and ensembles are not agreeing all of a sudden.thanks

[jmundie]

I think theres more of a chance it goes further south. Theres some mighty cold air pushing in from the plains