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What does everyone make of the dry air that seems to be entrenched along the spine of the apps.  Looks like the radar banding is setting up west of KTRI, down toward TYS.  Is the RAP the only model giving a widespread 2-4?

 

I'll be shocked if that doesn't fill in soon.

 

12z Hi-res NAM:

 

2uPIzHo.jpg

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If you believe the 12Z NAM most of the QPF is after lunch, but I think it is a little slow with this fast shortwave in a strong jet stream. Are we at half-time or just getting started? I'm giddy but skeptical. Regarding snow totals: Ratios could make up for wasted virga QPF.

 

First I want to note this system is coming from the southwest. It is not a clipper or front subject to downslope death off the Plateau. Elevation will be less of an advantage since we are all so cold, but I'd still expect the Upper Plateau and Smokies to perform better than the Valley.

 

Nowcasting data includes still developing mid-level clouds in northern Mississippi. New patches on weather radar in south-central Tenn. All this should move east-northeast toward East Tenn. Back edge of main band is about to arrive in Chatty so CHA needs some fill-in west. Looking great from Knoxville to TRI. You all are deeper in the main band and a little more on the track of developing echos.

 

NAM has .10 to .20 liquid which at high ratios would be excellent. I'd half it due to virga earlier; and, I think NAM is too slow. In other words I believe we are at half-time, NOT the first quarter NAM would indicate. Still that looks like 1-2 inches for everyone, except Chatty. Seriously, CHA is already close to the back but I think we might get nearly an inch. North Alabama might snag an inch as well. I like 1-2 inches Knoxville and 2-3 inches TRI. Upper Plateau may reach 3 inches. Smokies should do even better. Southwest NC higher elevations should do well (up to 3") in this set-up too since the main event is southeast of here.

 

EDIT: Just issued MRX area fcst disco looks great. They seem to speed up the system a bit compared to NAM but not as much as I was worried about. Note radar echos southern Middle Tenn. MRX has us in the second quarter, still not quite half-time!

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If you believe the 12Z NAM most of the QPF is after lunch, but I think it is a little slow with this fast shortwave in a strong jet stream. Are we at half-time or just getting started? I'm giddy but skeptical. Regarding snow totals: Ratios could make up for wasted virga QPF.

 

First I want to note this system is coming from the southwest. It is not a clipper or front subject to downslope death off the Plateau. Elevation will be less of an advantage since we are all so cold, but I'd still expect the Upper Plateau and Smokies to perform better than the Valley.

 

Nowcasting data includes still developing mid-level clouds in northern Mississippi. New patches on weather radar in south-central Tenn. All this should move east-northeast toward East Tenn. Back edge of main band is about to arrive in Chatty so CHA needs some fill-in west. Looking great from Knoxville to TRI. You all are deeper in the main band and a little more on the track of developing echos.

 

NAM has .10 to .20 liquid which at high ratios would be excellent. I'd half it due to virga earlier; and, I think NAM is too slow. In other words I believe we are at half-time, NOT the first quarter NAM would indicate. Still that looks like 1-2 inches for everyone, except Chatty. Seriously, CHA is already close to the back but I think we might get nearly an inch. I like 1-2 inches Knoxville and 2-3 inches TRI. Upper Plateau may reach 3 inches. Smokies should do even better. Southwest NC higher elevations should do well (up to 3") in this set-up too since the main event is southeast of here.

Very informative post, thanks for sharing your thoughts. Much appreciated.

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If you believe the 12Z NAM most of the QPF is after lunch, but I think it is a little slow with this fast shortwave in a strong jet stream. Are we at half-time or just getting started? I'm giddy but skeptical. Regarding snow totals: Ratios could make up for wasted virga QPF.

 

First I want to note this system is coming from the southwest. It is not a clipper or front subject to downslope death off the Plateau. Elevation will be less of an advantage since we are all so cold, but I'd still expect the Upper Plateau and Smokies to perform better than the Valley.

 

Nowcasting data includes still developing mid-level clouds in northern Mississippi. New patches on weather radar in south-central Tenn. All this should move east-northeast toward East Tenn. Back edge of main band is about to arrive in Chatty so CHA needs some fill-in west. Looking great from Knoxville to TRI. You all are deeper in the main band and a little more on the track of developing echos.

 

NAM has .10 to .20 liquid which at high ratios would be excellent. I'd half it due to virga earlier; and, I think NAM is too slow. In other words I believe we are at half-time, NOT the first quarter NAM would indicate. Still that looks like 1-2 inches for everyone, except Chatty. Seriously, CHA is already close to the back but I think we might get nearly an inch. North Alabama might snag an inch as well. I like 1-2 inches Knoxville and 2-3 inches TRI. Upper Plateau may reach 3 inches. Smokies should do even better. Southwest NC higher elevations should do well (up to 3") in this set-up too since the main event is southeast of here.

 

EDIT: Just issued MRX area fcst disco looks great. They seem to speed up the system a bit compared to NAM but not as much as I was worried about. Note radar echos southern Middle Tenn. MRX has us in the second quarter, still not quite half-time!

 

Cuj4Yau.gif

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Be fun to do a follow-up to this one...the models really struggled with this one until the last minute in terms of real weather in the TN Valley.  It is a great example of how southern stream energy can get a mind of its own.  Any storm that is "turning the corner" in Georgia should be watched until it exits the SE.  Was really enjoyable to track.  Let's see if we can do it again. 

 

edit:  Also, ALL winter the arctic fronts have been slower than estimated or didn't go as far south as modeled.  I think we benefited ever sow slightly with southern stream moisture catching the boundary that took its time sinking south.

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The 700mb humidity told the tale, we had a little bit of lift and good 700mb humidity was modeled long before the QPF responded. When it's so cold if you can saturate that level of the atmosphere, you will usually receive snow with even mild lift.

 

The humidity was higher, longer, the further south and east you went, you guys in that zone got the most snow as a result.

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It was a very intriguing storm to track. I was also really impressed with the RAP model with this event, it pretty much nailed it. It also done extremely well for this area with the Christmas 2010 storm, back when it was known as the RUC.

I ended up with 3.2 inches here and got down to 0 last night, which was well below the forecast low. That's the coldest temperature I have recorded all winter (or ever lol), previous was 2.3 with the first extreme arctic blast 2 or 3 weeks ago.

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Special Weather Statement

SPECIAL WEATHER STATEMENT

NATIONAL WEATHER SERVICE NASHVILLE TN

356 PM CST THU JAN 30 2014

TNZ005>011-022>034-056>066-075-077>080-093>095-310400-

STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-

HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-

SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-

WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DE KALB-WHITE-

CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-

GILES-

INCLUDING THE CITIES OF...DOVER...CLARKSVILLE...SPRINGFIELD...

GALLATIN...LAFAYETTE...CELINA...BYRDSTOWN...CAMDEN...ERIN...

WAVERLY...DICKSON...ASHLAND CITY...NASHVILLE...LEBANON...

MOUNT JULIET...HARTSVILLE...CARTHAGE...GAINESBORO...COOKEVILLE...

LIVINGSTON...JAMESTOWN...LOBELVILLE...CENTERVILLE...HOHENWALD...

FRANKLIN...BRENTWOOD...COLUMBIA...LEWISBURG...MURFREESBORO...

WOODBURY...SMITHVILLE...SPARTA...CROSSVILLE...SHELBYVILLE...

TULLAHOMA...MANCHESTER...MCMINNVILLE...ALTAMONT...SPENCER...

WAYNESBORO...LAWRENCEBURG...PULASKI

356 PM CST THU JAN 30 2014

...WEATHER PATTERNS WILL CHANGE NEXT WEEK AND BRING INCREASED

STORMINESS TO MIDDLE TENNESSEE...

FOR WEEKS NOW...MIDDLE TENNESSEE WEATHER HAS BEEN STRONGLY

AFFECTED BY THE NORTHERN JET STREAM...CHARACTERIZED BY REPEATED

EPISODES OF COLD AIR. IN ADDITION...ATMOSPHERIC MOISTURE HAS BEEN

VERY LIMITED...AND MEASURABLE SNOWFALL HAS BEEN CONFINED MAINLY TO THE

CUMBERLAND PLATEAU.

THE SOUTHERN JET STREAM...WHICH TYPICALLY SPREADS INCREASED ATMOSPHERIC

MOISTURE FROM THE GULF OF MEXICO UP ACROSS OUR AREA...HAS BEEN

ABSENT FROM OUR WEATHER PICTURE FOR A NUMBER OF WEEKS. HOWEVER...

THAT IS EXPECTED TO CHANGE NEXT WEEK...AS SEVERAL LOW PRESSURE

SYSTEMS ARE FORECAST TO DEVELOP OVER THE GULF COASTAL REGION AND

SPREAD PRECIPITATION UP ACROSS MIDDLE TENNESSEE. AT THE SAME

TIME...THE NORTHERN JET STREAM WILL CONTINUE TO SEND COLD AIR

SOUTHWARD OUT OF CANADA. THIS COMBINATION...OF COLD AIR FROM THE

NORTH AND INCREASED ATMOSPHERIC MOISTURE FROM THE SOUTH...WILL

MAKE FOR AN INTERESTING WEATHER PATTERN NEXT WEEK.

THE FIRST LOW PRESSURE SYSTEM NEXT WEEK IS FORECAST TO SWING FROM

TEXAS TO PENNSYLVANIA AND WILL LIKELY BRING ALONG SOME HEAVY

RAINFALL NEXT TUESDAY AND TUESDAY NIGHT. THERE MAY BE SOME

THUNDERSTORMS RUMBLING THROUGH AS WELL. THIS WILL BE FOLLOWED BY

SOME MUCH COLDER AIR ON WEDNESDAY...ALONG WITH A CHANCE FOR LIGHT

SNOW. TEMPERATURES WILL FALL FROM THE 50S AND 60S TUESDAY...INTO

THE 30S ON WEDNESDAY.

DRY AND COLD WEATHER IS FORECAST FOR NEXT THURSDAY.

HOWEVER...A SECOND LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP

OVER THE GULF COASTAL REGION LATE NEXT WEEK...ON FRIDAY OR

SATURDAY. SINCE CHILLY AIR WILL ALREADY BE IN PLACE OVER MIDDLE

TENNESSEE...IT IS POSSIBLE WE COULD BE LOOKING AT SOME WINTRY

PRECIPITATION AS WE HEAD INTO NEXT WEEKEND.

SPECIFIC DETAILS OF THE WEATHER NEXT WEEK...REGARDING THE TIMING

AND INTENSITY OF PRECIPITATION...AS WELL AS THE TYPE OF

PRECIPITATION...WILL BECOME MORE CLEAR AS WE GET CLOSER TO THE

ACTUAL EVENTS. HOWEVER...SUFFICE IT TO SAY THAT MIDDLE TENNESSEE

WEATHER WILL UNDERGO SOME FREQUENT CHANGES NEXT WEEK... AND IT

WILL BE A TIME WHEN YOU WILL WANT TO KEEP AN EYE ON YOUR LOCAL

FORECAST IN ORDER TO KNOW WHAT CHANGES TO EXPECT...AND WHAT TYPE

PRECIPITATION MAY BE COMING DOWN THE PIKE.

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Impressive that they put this out so early. I wish MRX did more things like this, but they are generally a bit behind with graphics and always much more sparse with discussion that surrounding forecast offices.

 

I do hate that the battle zone always seems to set up over some part of Tennessee. This one looks like it could be a classic 1-40 and north storm on the Euro. I'd like to see it be an I-20 to I-64 storm.

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0z Nam lays down a nice little swath of snow on Sunday, very similar to GGEM.

Memphis to Dickson to Nashville to Upper Cumberland and points north and west. 2-4 inches.

 

Taken verbatim most of that clown map is not snow.  BNA goes over to snow/sleet at hour 81 with very little precip left.  It is very close but too warm from 700mb down to 850mb.  00z GFS came in a bit colder as well.  Sunday night is looking more and more interesting.

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My point forecast for Sunday night/Monday.

 

Sunday Night - Rain showers likely before 1am, then snow showers likely. Mostly cloudy, with a low around 30. Chance of precipitation is 60%

 

Monday - Snow showers likely before 10am, then rain showers. Partly sunny, with a high near 40. Chance of precipitation is 60%

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The 06z NAM really drops the hammer on East Tennessee from 40 north, with the Sunday night system, 8-14 inches for the KY/VA border areas with 3-5 over the Nashville area.

 

We're going to be on the borderline for it. JKL says moderate to significant totals possible for their CWA and says it'll be a mostly snow event for them,

 

Nash has Snow/Sleet for their CWA north of 40. 

 

East Tennessee NAM 10:1 snow map.

 

6znam310.jpg

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06z GFS is slightly warmer and therefore snow totals are much lower.

 

The NAM has the 850 and surface freezing line pretty close to 1-40 or just north of there with very heavy precip over running. It's gonna be a tight rain/snow cutoff. Heavy wet snow for those who get cold enough, heavy rain just on the edge.

 

The NAM has a look I'm very familiar with, some of my best snows have fallen from it and the snow line usually sets up right around the Campbell/Anderson line, drops towards Crossville in the West and runs up towards Kingsport in the East. The tier of counties along the border can have a monster snow event out of that set up.

 

That said, small shifts can make a major impact as you see how narrow that band of heavy snow is on the maps. The front stalls a little further south and most of Tennessee can get a thump, a bit further north and we sit in rain and watch it snow in Kentucky.

 

This is getting to be a serious enough look for most of the state to have a shot at something wintry and it's within 72 hours, so I'm starting a thread.

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