Jan 25th Winter Weather Discussion Thread

[Psalm 148:8]

From FFC....They are smart enough to cover themselves.....

 

INTERESTING FORECAST SHAPING UP FOR THURSDAY NIGHT AND FRIDAY
MORNING ACROSS GA. MODELS ARE IN UNANIMOUS AGREEMENT THAT STRONG CAD
WILL BE SETTING UP WITH THE CENTER OF A 1032 TO 1034 MB SURFACE HIGH
OVER NC OR VA BY 12Z FRIDAY. ALOFT...ISENTROPIC PROCESSES WILL
COMMENCE ACROSS THE REGION IN RESPONSE TO A SHORTWAVE TROF MOVING
THROUGH THE GREAT LAKES REGION THURSDAY NIGHT INTO FRIDAY MORNING.
ANALYSIS OF THE 295 THETA SURFACE IN THE GFS AND NAM SHOW ISENTROPIC
LIFT STARTING AFTER MIDNIGHT THURSDAY AND INCREASING THROUGH 18Z
FRIDAY PARTICULARLY ACROSS NORTH AND CENTRAL GA WITH 50 TO 70 MB OF
UPGLIDE AND LESS THAN 10 MB REQUIRED TO SATURATE AND PRECIPITATE. AT
THE SURFACE...COLD AIR ADVECTION OUT OF THE EAST WILL BE
UNDERCUTTING THE WEST SOUTHWEST TO WEST WINDS AT ABOUT 900 MB UP TO
ABOUT 600 MB. MODEL SOUNDINGS FROM BOTH THE NAM AND GFS SHOWING
STRONG WEDGE AT THE SURFACE UP TO 925 MB ESPECIALLY ALONG AND NORTH
OF I20...AND POSSIBLY AS FAR SOUTH AS A LA GRANGE TO MACON LINE.
WARM NOSE AROUND 850 MB IS QUITE WARM AND A POSSIBLE CAUSE FOR BUST
CONCERN AS MODELS INDICATING TEMPS AS WARM AS 44 TO 45 DEG F IN THE
WARM NOSE...HOWEVER...THE COLD WEDGE IS AS LOW AS 21 DEG F AT ITS
COLDEST POINT WHICH WOULD BE MORE THAN COLD ENOUGH TO COMPENSATE FOR
A SLIGHTLY WARMER WARM NOSE. NAM...GFS...SREF...AND ECMWF ALL AGREE
THAT PARTIAL THICKNESS VALUES IN THE 1000-850 MB AND 850-700 MB
LEVELS ALIGN WELL IN THE FREEZING RAIN CATEGORY. ALL THAT
SAID...WILL INTRODUCE FREEZING RAIN POSSIBLY MIXED WITH SLEET
ACROSS MOST OF CENTRAL...NORTHWEST AND NORTHEAST GA THURSDAY NIGHT
THROUGH FRIDAY MIDDAY. ALONG AND WEST OF I75 WILL WARM ENOUGH BY
AROUND NOON THAT FZRA SHOULD CHANGE TO RAIN...HOWEVER POINTS FURTHER
EAST AND NORTH MAY STAY FZRA INTO MID TO LATE AFTERNOON AS THE WEDGE
SLOWLY ERODES. TOTAL QPF NOT ALL THAT IMPRESSIVE..HOWEVER...SINCE
THE PTYPE WILL LIKELY BE OF AN ICE VARIETY...IMPACTS WILL BE MUCH
GREATER PARTICULARLY ON TRAVEL FRIDAY AM. 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.
 

[SnowGoose69]

Lol you guys are right ffc is the kiss of death

This is a pretty marginal event at best...the precipitation probably would have to arrive before 12Z to get the evaporative cooling really going...all in all this is mainly a threat to ATL airport's operations more than anything else.  I think the roads would be okay given the daytime highs are going to pretty warm leading into the event this week.

[franklin NCwx]

Jma is a beast.

[burgertime]

I bet burger, strong, and beanskip like the 6z nam snowfall map.

 

Even though it looks more like an ice storm I'm liking the trend of the NAM...but in the end it's the NAM out to 60+ hours. I do like that it seems to get slightly colder for MBY...that storm last week has me a little miss trustful of the lol even though this is a totally different setup.

[burgertime]

JMA....for historical reasons....I'll believe it when it's over....it's hard to see but anything above that pink line should be snow. 

 

[strongwxnc]

Ahh... Moblie now and cannot bring the map up. Dang

I bet burger, strong, and beanskip like the 6z nam snowfall map.

[franklin NCwx]

Ahh... Moblie now and cannot bring the map up. Dang

mobile too but it paints a 3-6 swath across sothern nc from around Murphy to almost the nc coast

[NCSNOW]

JMA....for historical reasons....I'll believe it when it's over....it's hard to see but anything above that pink line should be snow. 

Wouldn't that be nice. Do you have precip totals off euro for Greensboro, Raleigh ,Charlotte. James made it sound like maybe .25 for most in NC I'm guessing. Thanks a mill!

[FallsLake]

^{RAH this morning not impressed with the amount of precip on models. In fact their title to the event was "...A FADING POTENTIAL OF A WINTERY MIX FRIDAY INTO FRIDAY NIGHT?" They are concerned about the trend towards less precip. Maybe with the 6Z NAM and hopefully the 12 models the trend will reverse. **They also mentioned the possibility that some could receive a light dusting tonight (mainly north of US-64).} 

 

[burgertime]

Wouldn't that be nice. Do you have precip totals off euro for Greensboro, Raleigh ,Charlotte. James made it sound like maybe .25 for most in NC I'm guessing. Thanks a mill!

 

Euro was around .25 - .30 for all of NC. 

[beanskip]

Who cares what those goofy snowfall maps show, it's an ice sounding for almost the entire event.

I bet burger, strong, and beanskip like the 6z nam snowfall map.

[burgertime]

Who cares what those goofy snowfall maps show, it's an ice sounding for almost the entire event.

 

I think the reason they are doing that is because of the thickness profile...the snow maps anyways. 

[franklin NCwx]

Who cares what those goofy snowfall maps show, it's an ice sounding for almost the entire event.

I guess Mark did, clearly you don't. It is helpful with seeing where the max qpf strip is put down and that is over southern nc

[Lookout]

Woohooo!!! Kiss of death, Atlanta is on board http://www.daculaweather.com/4_afd_ffc.php

 

 

lol at channel 2 and 5 going from 56 to 39/45 for highs respectfully friday. (and even that's too warm...especially east/ne of town where nam is showing temps staying in the 20s most of the day and below freezing until it's over).

 

Good discussion from ffc (unlike yesterday) but they went from mid 50s to a high of 34 for many areas friday in one forecast cycle with the freezing rain. Smart but for the regular joe, they are probably thinking wtf.

[msuwx]

Who cares what those goofy snowfall maps show, it's an ice sounding for almost the entire event.

Yes, 6z NAM was IP and ZR for CLT. 

[beanskip]

If you are interested in QPF maxes I recommend the handy dandy QPF MAPS that accompany most model runs.

I guess Mark did, clearly you don't. It is helpful with seeing where the max qpf strip is put down and that is over southern nc

[deltadog03]

lol at channel 2 and 5 going from 56 to 39/45 for highs respectfully friday. (and even that's too warm...especially east/ne of town where nam is showing temps staying in the 20s most of the day and below freezing until it's over).

 

Good discussion from ffc (unlike yesterday) but they went from mid 50s to a high of 34 for many areas friday in one forecast cycle with the freezing rain. Smart but for the regular joe, they are probably thinking wtf.

Yes sir, I think that was mr Nelson doing the disco. I was talking to him, on chat, last night about some of these model solutions. With that said, RPM has really backed off this am. Lol

[SnowGoose69]

Yes, 6z NAM was IP and ZR for CLT. 

Yeah, mostly SN too for RDU but with screaming WSW flow in the mid-levels and the temps near 0c I think I'd go with PL for RDU and mostly ZR at CLT and GSP.

[strongwxnc]

I love a good snow map For at least I can have 6 hours of fantasy snow before the next model run

 

Who cares what those goofy snowfall maps show, it's an ice sounding for almost the entire event.

 

 

I guess Mark did, clearly you don't. It is helpful with seeing where the max qpf strip is put down and that is over southern nc

[DaculaWeather]

Yes sir, I think that was mr Nelson doing the disco. I was talking to him, on chat, last night about some of these model solutions. With that said, RPM has really backed off this am. Lol

Stellman did that long term. Who ever TDP is there, he does a great job with discos. I've sent them several emails lately commending him on how detailed he was. They are all getting better I think.

[Lookout]

Yes sir, I think that was mr Nelson doing the disco. I was talking to him, on chat, last night about some of these model solutions. With that said, RPM has really backed off this am. Lol

You can tell him that discussion was good. Edit, dacula is right..it was stellman. baker did the short term and I can only assume they must have agreed.

 

btw, channel 11 (with their insanely stupid "wizamater" or whatever it's called) is still showing 56 friday for atlanta lol

[deltadog03]

Ya y'all are right. I thought it was, my bad. Great disco though! RPM still shoes sub freezing 2m temps fri down to SGA.

[scsnowgirl]

GSP....

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...

AS OF 3 AM EST WED...THE MAIN CONCERN FOR THE SHORT TERM PERIOD WILL

BE THE POTENTIAL FOR ACCUMULATING WIDESPREAD WINTRY PRECIP ON FRI AS

THE LATEST MODELS HAVE TRENDED MUCH COLDER WITH TEMPS DURING THIS

PERIOD.

QUIET CONDITIONS TO START THE PERIOD ON THURSDAY AS WEAK H5 RIDGING

BUILDS IN FROM THE WEST AND THE UPPER TROUGH AXIS MOVES OFFSHORE.

STRONG CANADIAN SURFACE HIGH PRESSURE CENTERED OVER THE WESTERN

GREAT LAKES REGION THU MORNING WILL MOVE EASTWARD INTO THE UPPER

OHIO VALLEY BY 00Z FRI WHICH WILL LEAD TO CAA NORTHERLY FLOW OVER

THE REGION TOWARD LATE THURSDAY. EXPECT PARTLY CLOUDY SKIES WITH

TEMPERATURES A FEW DEGREES BELOW NORMAL FOR MOST LOCATIONS ON

THURSDAY. FOR THURSDAY NIGHT...HIGH PRESSURE WILL NOSE DOWN INTO THE

CAROLINAS AND BECOME CENTERED ACROSS THE EASTERN NC PIEDMONT.

MEANWHILE...LOW PRESSURE OVER THE NORTHERN PLAINS WILL MOVE INTO THE

MIDWEST BY THU NIGHT. A WARM FRONT OVER THE DEEP SOUTH WILL PUSH

INTO THE TN VALLEY AT THAT TIME BRINGING INCREASING LLVL MOISTURE

LEADING TO THE DEVELOPMENT OF PRECIP OVER THE WESTERN ZONES EARLY

FRI.

MODELS HAVE TRENDED SLOWER WITH ONSET OF PRECIP FRI MORNING AS THE

HIGH CENTERED JUST TO THE EAST WILL PERSIST THROUGH THE MORNING

HOURS. THIS WILL LEAD TO MUCH COLDER MORNING LOWS WITH DRIER

CONDITIONS OVER MUCH OF THE REGION FRI MORNING. THE LATEST MODELS

FINALLY BRING WARM FRONT PRECIP INTO WESTERN HALF OF THE CWA BY 15Z

FRI AND INTO THE REST OF THE FA BY 18Z FRI. TEMPERATURES LOOK TO BE

MUCH COLDER DURING THE DAYTIME ON FRI AS A COLD AIR DAMMING

WEDGE PERSISTS AT LEAST THROUGH LATE FRI AFTERNOON.

THEREFORE...HIGHS ON FRI WILL RUN NEAR FREEZING ACROSS MUCH OF THE

REGION WHICH WILL LEAD TO A WIDESPREAD WINTRY MIX PRECIP EVENT.

MODEL SOUNDINGS SUGGEST THAT A WARM NOSE WILL BE PRESENT IN THE

H85-H7 LAYER WITH SUB/FREEZING SURFACE TEMPERATURES DURING THE

DAYTIME HOURS. THIS WILL LEAD TO AREAS OF FREEZING RAIN MIXED WITH

SLEET/ICE PELLETS FOR MOST LOCATIONS THROUGH FRI AFTERNOON...THEN

CHANGING OVER TO RAIN BY EVENING WITH THE WEDGE ERODING. TOTAL

ACCUMULATIONS FROM THE WINTRY MIX PRECIP WILL RANGE FROM A HALF AN

INCH TO AN INCH DURING THIS EVENT. POPS REMAIN IN THE LIKELY

CATEGORY LATE FRI MORNING THROUGH THE AFTERNOON BEFORE TAPERING OFF

BY LATE FRI EVENING.

A DRIER AIR MASS MOVES IN BEHIND THE DEPARTING FRONTAL SYSTEM FOR

MOSTLY DRY CONDITIONS FRI NIGHT. THE NC MOUNTAINS HOWEVER WILL

SEE NORTHWEST FLOW UPSLOPE PCPN...WITH SNOW/ICE PELLETS DOMINANT PER

TOP DOWN TECHNIQUE. OVERNIGHT LOWS WILL CONTINUE TO BE 3-5 DEGREES

BELOW NORMAL GIVEN THE COLD AND DRY AIR MASS.

[Nraleigh]

JB this am says the storm for Friday looks to be a Friday Fizzler.

[Lookout]

JB this am says the storm for Friday looks to be a Friday Fizzler.

 

That's because it doesn't much effect the center of the weather universe..the mid atlantic and northeast. If it doesn't happen there, it doesn't happen at all.

[WhiteoutWX]

It's dubious to rely on the NAM for QPF totals, especially for this range. It's infamous for overdoing precip amounts. I would like to see the GFS come in wetter before I would feel better about this.

[franklin NCwx]

That's because it doesn't much effect the center of the weather universe..the mid atlantic and northeast. If it doesn't happen there, it doesn't happen at all.

he made three post about it yesterday as im sure he was getting nervous thst the trend was south of dc.

[eyewall]

SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...AS OF 310 AM WEDNESDAY....A FADING POTENTIAL OF A WINTERY MIX FRIDAY INTO FRIDAY NIGHT?VERY COLD AIR IN PLACE... SYSTEM MAY SHEAR OUT TOO MUCH TO DELIVERSIGNIFICANT PRECIPITATION...THE LATEST MODELS CONTINUE TO TREND COLDER AND EVEN DRIER NOW THANIN PREVIOUS RUNS WITH REGARDS TO THE POTENTIAL WINTER WEATHER EVENTFRIDAY INTO FRIDAY NIGHT. AT LEAST TWO OF THE OPERATIONAL MODELS(GFS AND NAM) ARE NOW FORECASTING LESS THAN 0.05 OF QPF. OTHERMODELS AND ENSEMBLE MEMBERS CONTINUE TO INDICATE JUST ENOUGH QPF TODELIVER WINTER P-TYPE PROBLEMS FOR OUR REGION. THE LATEST EC STILLFORECASTS AROUND 0.25 LIQUID FOR OUR NW ZONES... TAILING OFF TOAROUND 0.10 IN THE SE. HOWEVER... THE DRIER TRENDS WITH THE 00ZMODEL SUITE ARE CERTAINLY THE HEADLINER. IF THESE TRENDSCONTINUE...THEN CENTRAL NC WOULD HAVE VERY LITTLE IMPACT FROM THISEVENT.WE WILL CONTINUE TO LEAVE OUR CURRENT FORECAST OF A POTENTIAL WINTERWEATHER ADVISORY EVENT FOR FRI AND FRI EVENING... ESPECIALLY IN THEAREAS CURRENTLY MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK.THE ARCTIC (VERY DRY) AIR MASS IS FORECAST TO BE IN PLACE THURSDAYNIGHT INTO EARLY FRIDAY DRIVEN BY A 1035+ MB SURFACE HIGH THATBUILDS DOWN THE EASTERN SEABOARD FROM PA/NY. DEW POINTS ARE FORECASTTO BE IN THE 0-10 RANGE AT 12Z/FRIDAY WITH TEMPERATURES BETWEEN15-20 ACROSS CENTRAL NC. THIS SETS THE STAGE FOR THE POTENTIAL LIGHTWINTERY MIXTURE FOR FRIDAY AND FRIDAY NIGHT. HPC HAS BEEN LEANINGTOWARD A DRIER FORECAST GIVEN THE TRENDS IN THE MODELS... BUT STILLLEANS TOWARD A BLEND OF THE GEFS MEANS AND THE OPERATION EC.VIRTUALLY ALL MODEL SOLUTIONS SHEAR OUT THIS SYSTEM AND WEAKEN ITCONSIDERABLY AS IT MOVES ACROSS THE APPALACHIANS TO THE EASTERNSEABOARD FRIDAY INTO FRIDAY EVENING. GIVEN THE EXTENSIVE VERY DRYAIR IN PLACE... IT MAY BE DIFFICULT TO OVERCOME THE NOW WEAKER LIFTTO GENERATE QPF. THE LIGHTER QPF AND DRIER MOISTURE PROFILE ALSOAFFECTS THE P-TYPE SOMEWHAT... AS SOME MODELS SUGGEST INADEQUATEMOISTURE IN THE ICE NUCLEATION REGION FOR SNOW. THE LIGHTERPRECIPITATION WOULD LIKELY BE LIGHT SLEET OR LIGHT FREEZINGRAIN/RAIN DEPENDING ON THE SURFACE TEMPS FRIDAY. IN ADDITION...THERE IS CONSIDERABLE EVAPORATIVE COOLING POTENTIAL... BUT LACK OFQPF WOULD MEAN LESS COOLING ALLOWING SURFACE TEMPERATURES TOPOSSIBLY GO ABOVE 32 FRIDAY. HOWEVER... COLD AIR IS NOT AN ISSUE...BUT VERY DRY AIR AND A MORE SHEARED SYSTEM ALONG WITH LESS MOISTUREARE BIG ISSUES.

 

 

 

Can we delete the thread yet?

[WeatherNC]

JMA....for historical reasons....I'll believe it when it's over....it's hard to see but anything above that pink line should be snow. 

 

Since were posting Earl Barker model page maps, how about the UKMET, a run the HPC is discounting as being too amplified...

 

 

I still think there will be some changes over the next 24 hours, as the vorts in question move onshore over NA and are sampled via the RAOB network.  The question really is how much, if any, of the southern stream energy forecasted to move into northern California gets ingested into the northern parcel as it comes down from MT into the northern/central Plains.  The NAM leaves the bulk of it behind over central CA in the form of a ULL.  This is the only model showing that and therefore I would throw it out as T is stepped down range.  GFS appears on the weaker side of guidance, UKMET/GGEM on the wetter.  EC splits the difference roughly, a tenth or two for most areas with lackluster saturation through the column.  As I mentioned last night, I would become concerned if we started seeing amounts avg'ing less than a couple tenths, hopefully the QPF bleeding stops today and we see it come back around towards measurable amounts of precip.

[Cold Rain]

Since were posting Earl Barker model page maps, how about the UKMET, a run the HPC is discounting as being too amplified...

ukmet.JPG

I still think there will be some changes over the next 24 hours, as the vorts in question move onshore over NA and are sampled via the RAOB network. The question really is how much, if any, of the southern stream energy forecasted to move into northern California gets ingested into the northern parcel as it comes down from MT into the northern/central Plains. The NAM leaves the bulk of it behind over central CA in the form of a ULL. This is the only model showing that and therefore I would throw it out as T is stepped down range. GFS appears on the weaker side of guidance, UKMET/GGEM on the wetter. EC splits the difference roughly, a tenth or two for most areas with lackluster saturation through the column. As I mentioned last night, I would become concerned if we started seeing amounts avg'ing less than a couple tenths, hopefully the QPF bleeding stops today and we see it come back around towards measurable amounts of precip.

Good post. I agree. I think in the next 2-3 cycles, we'll see the QPF comes back as the energy in question gets sampled better.