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The Jan 9-10 Storm Part 4


Cheeznado

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what y'all think about this:

I think its great... still heavy precip. occurring too at 48 hours!

I hate to sound like a broken record, but the strength of the s/w and the speed that the 200mb low moves out of the way are absolutely key to our precipitation forecast, because a lot of our lift is created by divergence on the right entrance region of a jet streak. The NMM derivation of the WRF shows a jet-streak that is much more favorable for the promotion of divergence and lift over SC and NC, so its no surprise that the amounts are way up. The jet-streak quickly re-orients in an unfavorable position after 36 hours, but by that point the precipitation is already streaming in NC, and higher amounts are assured (per this model simulation)

2v2y743.png

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I think its great... still heavy precip. occurring too at 48 hours!

I hate to sound like a broken record, but the strength of the s/w and the speed that the 200mb low moves out of the way are absolutely key to our precipitation forecast, because a lot of our lift is created by divergence on the right entrance region of a jet streak. The NMM derivation of the WRF shows a jet-streak that is much more favorable for the promotion of divergence and lift over SC and NC, so its no surprise that the amounts are way up. The jet-streak quickly re-orients in an unfavorable position after 36 hours, but by that point the precipitation is already streaming in NC, and higher amounts are assured (per this model simulation)

Agreed. That's been a constant worry to me but it looks like it's getting out of the way just in enough time for increased precipitation amounts...at least the way I see it on some of the latest models regarding increased qpf.

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Looks dryer this run at hr30 compared to hr36 of last run. :thumbsdown: If the models continue with this trend, I won't even see a dusting.

Calm down dude... Greenville, SC is in excellent shape for this storm. No need to get all bent out of shape, especially when the RUC is looks more amplified.

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Calm down dude... Greenville, SC is in excellent shape for this storm. No need to get all bent out of shape, especially when the RUC is looks more amplified.

Everytime this area looks to be in excellent shape we get shafted. Has happened with the last three winter storms here. I sadly expect this time to be no different. I've come to get used to it though.

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Everytime this area looks to be in excellent shape we get shafted. Has happened with the last three winter storms here. I sadly expect this time to be no different. I've come to get used to it though.

This is a far different situation than the last few winters... we have not had such a cold airmass in place like this in a long long time. Folks that are comparing this to 1988 are right on the money.

Latest SREF guidance is interesting. There are still a few members painting widespread areas of 1" plus across WSC and WNC. I really like looking at the individual models, because you can see the "worst case senerio" in regards to convection in the Gulf of Mexico robbing moisture. I have circled the suite of SREF models that over emphasize convection. Even in this case, it looks like WNC and WSC get from .3-.8" in this worst case senerio of precipitation. Not to bad if we consider this our bottom line... if we don't end up with much convection near the gulf, you can throw those models out, and immediately the SREF mean goes way up.

261c6sl.png

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:) I certainly hope you're right Phil. Here is GSP's latest AFD:

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...

-- Changed Discussion --AS OF 300 AM SUNDAY...THE SRN STREAM SHORTWAVE IS STILL EXPECTED TO

DAMPEN AS IT REACHES THE SRN APPALACHIANS MON. SOME DEEP LAYER Q

VECTOR CONVERGENCE AHEAD OF THIS FEATURE SHOULD REACH THE REGION MON

MORNING BEFORE DIMINISHING THROUGH THE AFTERNOON. MODEL CONSENSUS

PLACES THE ASSOCIATED SFC LOW REFLECTION NEAR THE FL PANHANDLE BY

18Z MON. MODEL SOUNDINGS AND THICKNESSES CONTINUE TO SUPPORT MORE

SNOW THAN ANY OTHER PTYPE DURING THE BEST FORCING AND MOISTURE...AS

THEY SEEM TO BE GRADUALLY GETTING A BETTER HANDLE ON THE ARCTIC AIR

IN PLACE ACROSS THE REGION. QPF AMOUNTS...HOWEVER..CONTINUE TO POSE

THE GREATEST QUESTION. CONVECTION FROM THE FL PANHANDLE TO SE GA ON

MON COULD INHIBIT MOISTURE INFLUX INTO THE REGION. THE GFS SEEMS

MORE REASONABLE WITH THE LOWER QPF FOR THIS REASON. SLIGHTLY LOWER

QPF THAN PREVIOUSLY...BUT WITH SLIGHTLY COLDER PROFILES THAN

PREVIOUSLY...YIELDS A SIMILAR SNOW FORECAST. BASED ON ANTICIPATED 12

TO 24 HOUR SNOW ACCUMS RANGING FROM 6 TO 9 INCHES IN THE SW

MOUNTAINS TO 3 TO 5 INCHES ACROSS CHARLOTTE METRO...WILL GO AHEAD

AND POST A WINTER STORM WARNING FOR THE SRN TWO THIRDS OF THE

FORECAST AREA. THE WATCH WILL BE RETAINED TO THE NORTH. TEMPS WILL

BE COOLER THAN ALL MOS SOURCES ON MON WITH THE PRECIP ONSET INTO THE

DRY AIR.

THE POTENTIAL FOR ICING THEN BECOMES THE FOCUS THROUGH THE MON NIGHT

PERIOD. WEAK DEFORMATION FORCING COULD LINGER...ESPECIALLY OVER THE

NC PIEDMONT...AS THE COASTAL WATERS LOW SLOWLY DEEPENS AGAIN.

ADDITIONAL WEAK DIVERGENCE ALOFT NEAR THE EXIT REGION OF THE

TRAILING JET STREAK WILL ARRIVE MON NIGHT AS WELL. THE LEADING EDGE

OF THE STRONG MID LEVEL DRY PUNCH WILL WRAP SLOWLY ACROSS THE AREA

FROM SW TO NE MON NIGHT. THE SUDDEN DRYING WILL ALLOW ANY LINGERING

PRECIP TO CHANGE OVER TO FREEZING DRIZZLE OR VERY LIGHT FREEZING

RAIN AS ICE NUCLEI DISAPPEAR. HOWEVER...IT COULD TAKE MOST OF THE

NIGHT FOR A COMPLETE CHANGEOVER TO REACH THE NRN TIER OF THE

FORECAST AREA. GIVEN THE LIMITED QPF...ICE ACCUMS SHOULD STILL BE

LESS A TENTH OF AN INCH MOST AREAS.

THE NRN CONUS UPPER LEVEL LOW PRESSURE SYSTEM WILL DEVELOP EWD FROM

THE UPPER MIDWEST LATE MON NIGHT TO THE UPPER OH VALLEY BY LATE TUE.

ALL OF THE DEEP LAYER MOISTURE AHEAD OF THIS SYSTEM SHOULD BE NORTH

OF THE REGION BY TUE...BUT DRIZZLE OR FREEZING DRIZZLE COULD LINGER

GIVEN THE SW FLOW AND MOIST LOW LEVELS. WENT MUCH COOLER THAN MOS

AGAIN FOR TUE TEMPS WITH SLOWLY DISSIPATING CAD BETWEEN THE COASTAL

AND OH VALLEY SYSTEMS.

STRONGLY CHANNELED VORTICITY ALONG THE SRN PERIPHERY OF THE DEEP 500

MB SYSTEM WILL BRUSH THE FAR NRN TIER OF THE FORECAST AREA TUE NIGHT

THROUGH WED...BUT ANY QPF WOULD BE QUITE LIMITED. A BETTER CHANCE OF

PRECIPITATION WILL BE FOUND IN INCREASING NW FLOW MOISTURE NEAR THE

TN BORDER TUE NIGHT THROUGH WED. ADDITIONAL LIGHT SNOW ACCUMS WILL

BE POSSIBLE IN THE UPSLOPE PREFERRED SECTIONS OF THE SRN

APPALACHIANS THROUGH WED.-- End Changed Discussion --

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This is a far different situation than the last few winters... we have not had such a cold airmass in place like this in a long long time. Folks that are comparing this to 1988 are right on the money.

Latest SREF guidance is interesting. There are still a few members painting widespread areas of 1" plus across WSC and WNC. I really like looking at the individual models, because you can see the "worst case senerio" in regards to convection in the Gulf of Mexico robbing moisture. I have circled the suite of SREF models that over emphasize convection. Even in this case, it looks like WNC and WSC get from .3-.8" in this worst case senerio of precipitation. Not to bad if we consider this our bottom line... if we don't end up with much convection near the gulf, you can throw those models out, and immediately the SREF mean goes way up.

261c6sl.png

I am with you Phil. This thing is so on! If you look at the NAM temps (not QPF), they fit the bill for our areas. The snow ratios will be insane at the start (will help make up for qpf eaten up by the dry air) and the GFS/RUC precip totals are inching up there! Lastlly, the NAM is showing a strong CAD sig up to the end of the storm. I am betting on most of this being snow, with changover the last few hours of the storm to snow/ip and then a slow freezing drizzle to end the storm. This has 1988 written ALL OVER IT! One other thing to watch is the coastal lp as well. The way I look at it? We are a lock for some snow/wintry weather. Everything else is bonus from here? At least we are not SEARCHING for "what if's" to try to FIND a way that wintry weather "might happen". This is a classic SE storm, like back in the day! :drunk:

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The southern 2/3 of the NWS-GSP zone is now under a Winter Storm Warning. The 1-09-11 morning discussion is a very well thought through one by GSP (as always-they always seem to have their act together!). A snippet from the discussion talks about the decrease in moisture from the models. However, they reconize that the 850's are trending colder, so this makes up for the decrease of qpf with better snow ratios! They also mentioned prolonged deformation in the NC Piedmont. I am patiently waiting the GFS 06z run to see if there is any change with the QPF in regards to trends. The only thing that concerns me now is the mention of convection robbing moisture from us during the height of our the storm, when we have our best lift. Wishing everyone luck. This shall be a fun ride! :snowman::scooter:

EDIT: I forgot to mention that I spot checked discussions from various NWS Offices from Bama to the Carolinas and it appears that the orginal forecast low temps had to be adjusted DOWN. This means that there is more cold air settling in and could possibly help down the road with delaying the effects of the warm nose = longer duration of snow. :weight_lift:

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I am with you Phil. This thing is so on! If you look at the NAM temps (not QPF), they fit the bill for our areas. The snow ratios will be insane at the start (will help make up for qpf eaten up by the dry air) and the GFS/RUC precip totals are inching up there! Lastlly, the NAM is showing a strong CAD sig up to the end of the storm. I am betting on most of this being snow, with changover the last few hours of the storm to snow/ip and then a slow freezing drizzle to end the storm. This has 1988 written ALL OVER IT! One other thing to watch is the coastal lp as well. The way I look at it? We are a lock for some snow/wintry weather. Everything else is bonus from here? At least we are not SEARCHING for "what if's" to try to FIND a way that wintry weather "might happen". This is a classic SE storm, like back in the day! :drunk:

Well in that case, I wish I knew what the 88 storm brought here, buuttt considering I was one at the time I don't. Guess I will google. Nevertheless, things are trending positive it looks like you guys are saying.

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