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February 8-12 2016 Cold and Possibly Snowy


tnweathernut

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There's excellent cold through the entire column for top down cooling to occur quickly. If it rains at all it will be super cooled rain drops that fall almost all the way to the surface as snowflakes. That should do the trick with no midlevel warm nosing being forecast.

yup.i agree i dont buy the change over Monday to rn/sn here.But, occluded systems suck and bring in warmer air into them,we'll see

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Something that's kinda throwing me off is that most of the local news stations are forecasting mostly rain for Monday in the valley, and it won't change over to Snow until the night hours.

I don't completely understand the thought of no dynamic cooling being forecast.  Even NWS pinpoint now has me as Snow rain mix until 7am then switching to rain until 5PM.  Just doesn't make any sense to me unless they are all seeing the column differently.  I have had a hard time with this going back for several days as there is no mid-level warming modeled and cold just keeps crashing in upper levels while the surface is at or just barely above freezing for many when this starts.  

 

MRX mentioned advisory level snows starting tomorrow night through tuesday night for most areas.  

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Looks like 1-2 for the Knoxville area, then a dusting for valley areas southwest of Knoxville.

Honestly, even in Kingsport I have my doubts at getting over 2". The closer to the Plateau, the lower amounts will be IMO. Closer to the Apps, the better. JC could easily get 3-4". I have my expectations set pretty low. Anything over 2" will be a bonus. Nonetheless, in a winter that has had limited chances to track storms, I am still interested in the event. Long duration light snow will be fun to lool at...

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In other words, this is the RGEM without the adjusted ratio?

Exactly. Also, the entire event is not modeled since it only runs to 48. Usually, these events have surprises both good and bad. Usually have to be on a west facing slope and near some elevation. Knoxville and Kingsport struggle with these events. Though sometimes, things do settle into the Valley. IMBY, any snow is bonus snow from northwest flow events. But w the cold around it may make travel tough, so that will keep it interesting. The Plateau, sw VA, foothills communities, and the Apps should be in a great spot.

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Here is my dilemma with this.  I normally don't trust qpf from the NAM but my distrust on NAM qpf is it usually from my watching it over the years is its usually liberal in qpf, not conservative.  That concerns me with this as dry as the NAM is showing in comparison to the GFS and Euro which are much more generous in qpf for this event.  What they all generally have in common is lift, moisture seems to be the disagreement.  Considering the RGEM with its very limited time on this event looks to me to be echoing closer to the GFS and Euro in qpf, I think I would lean on a blend of GFS/Euro/RGEM.  The NAM being so completely different makes me wonder if its not getting the qpf right.  

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Honestly, even in Kingsport I have my doubts at getting over 2". The closer to the Plateau, the lower amounts will be IMO. Closer to the Apps, the better. JC could easily get 3-4". I have my expectations set pretty low. Anything over 2" will be a bonus. Nonetheless, in a winter that has had limited chances to track storms, I am still interested in the event. Long duration light snow will be fun to lool at...

Yeah I think we could do well here. It seems the GFS has been pretty consistent in showing that as well. Isn't the GFS supposedly pretty good at handling northern energy? I'm pretty excited about the event regardless of the results. Days of flakes flying and cold temps. Plus, it looks like more could be coming toward the end of the week. Could shape up to be a pretty good week of winter.

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Here is my dilemma with this.  I normally don't trust qpf from the NAM but my distrust on NAM qpf is it usually from my watching it over the years is its usually liberal in qpf, not conservative.  That concerns me with this as dry as the NAM is showing in comparison to the GFS and Euro which are much more generous in qpf for this event.  What they all generally have in common is lift, moisture seems to be the disagreement.  Considering the RGEM with its very limited time on this event looks to me to be echoing closer to the GFS and Euro in qpf, I think I would lean on a blend of GFS/Euro/RGEM.  The NAM being so completely different makes me wonder if its not getting the qpf right.

Usplope events are notoriously difficult to predict. They tend to trend north w time. This one seems to be a bit of a different animal in that it "may" involve some areas not used to upslope.

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I say this with basically every storm or event, but it's all about knowing your local microclimate. How well do you do with these type of events? The biggest thing is how much rain falls. Every model and met seems to suggest it will rain for basically everyone below 2500 feet for a good portion of Monday. It doesn't make a whole lot of sense to me based on the upper levels but we have to assume we lose qpf for that. Heights will crash quickly and go over to higher ratio snows from East to West throughout the day. After that it's just how much lake and Atlantic moisture is around to be squeezed out over the next 36 hours. 

 

The other thing will be how fast the waves move through, how much snow falls in wave one in your area, etc. Even on frigid days when the sun coming out on this high ratio snow will melt it away. I could see half an inch falling, then it melting, another half falling, that melting etc etc.

 

There is a second clipper coming Friday or Friday night that might squeeze out an additional dusting to an inch in places.

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Yeah I think we could do well here. It seems the GFS has been pretty consistent in showing that as well. Isn't the GFS supposedly pretty good at handling northern energy? I'm pretty excited about the event regardless of the results. Days of flakes flying and cold temps. Plus, it looks like more could be coming toward the end of the week. Could shape up to be a pretty good week of winter.

Silas, I agree. Can't be all bad if the flakes are flying. Definitely deserves a thread. Also, a quick drive to the mtns and many can still experience the event. Sometimes we get zero in KPT w these events. We just drive to Roan Mtn State Park and often see quite a bit even at lower elevations. Looks like the northern Valley has a shot though.

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Usplope events are notoriously difficult to predict. They tend to trend north w time. This one seems to be a bit of a different animal in that it "may" involve some areas not used to upslope.

I agree this one does seem to be a different animal.  Its strength is really notable.  Usually with these lows seeing Winter Weather Advisories even the occasional WSW in the upper midwest isn't uncommon, this one however has full on Blizzard warnings (of course due to tight pressure gradient) as far south as central Iowa, as a testament to the strength of this low.

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One of the things though that has me a little more optimistic is the national radar mosaic is showing as pretty primed with moisture for this early.  Even the juicy GFS doesn't model quite this much qpf as being represented on current returns as far south as Kansas and Oklahoma (Tulsa radar) at this early early stage of the game.  Though I would venture virga that far south, but a sign of moisture none-the-less.

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Winter Weather Advisory has been issued for the Plateau.

CLAY-PICKETT-JACKSON-PUTNAM-OVERTON-FENTRESS-DE KALB-WHITE-

CUMBERLAND-WARREN-GRUNDY-VAN BUREN-

INCLUDING THE CITIES OF...CELINA...BYRDSTOWN...GAINESBORO...

COOKEVILLE...LIVINGSTON...JAMESTOWN...SMITHVILLE...SPARTA...

CROSSVILLE...MCMINNVILLE...ALTAMONT...SPENCER

107 PM CST SUN FEB 7 2016

...WINTER WEATHER ADVISORY IN EFFECT FROM NOON MONDAY TO 6 PM CST

TUESDAY...

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A WINTER

WEATHER ADVISORY FOR SNOW...WHICH IS IN EFFECT FROM NOON MONDAY

TO 6 PM CST TUESDAY.

* TIMING...NOON MONDAY UNTIL 6 PM CST TUESDAY.

* MAIN IMPACT...HAZARDOUS TRAVEL CONDITIONS.

* TOTAL SNOW ACCUMULATIONS...1 TO 2 INCHES WITH LOCALLY HIGHER

AMOUNTS.

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URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE MORRISTOWN TN

332 PM EST SUN FEB 7 2016

...WINTER STORM TO IMPACT THE REGION MONDAY MORNING THROUGH AT

LEAST TUESDAY NIGHT...

.A COLD FRONT IS FORECASTED TO MOVE IN FROM THE NORTHWEST

OVERNIGHT AND BRING WITH IT MUCH COLDER TEMPERATURES AND SNOW. SNOW

WILL MOVE IN FROM THE NORTHWEST OVERNIGHT INTO MONDAY MORNING.

DEPENDING ON HOW FAST THIS SYSTEM MOVES...SNOWFALL COULD BE SEEN

MONDAY MORNING BEFORE TEMPERATURES WARM UP DURING THE DAY AND THE

SNOW THEN TRANSITIONS TO RAINFALL FOR THE REST OF THE DAYLIGHT

HOURS. ONCE TEMPERATURES DROP BELOW FREEZING ON MONDAY NIGHT THEY

WILL REMAIN BELOW FREEZING THROUGH AT LEAST TUESDAY OR WEDNESDAY.

WHILE IT MAY NOT BE SNOWING DURING THE ENTIRE TIME DURING THE

ADVISORY THE COLD TEMPERATURES WILL MAKE THE THREAT FOR

ACCUMULATING SNOWFALL PRESENT DURING THE FIRST HALF OF THE WORK

WEEK.

TNZ012>016-035-037>040-042-044-080445-

/O.NEW.KMRX.WW.Y.0005.160208T1200Z-160210T0000Z/

SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-MORGAN-UNION-GRAINGER-

HAMBLEN-NORTHWEST COCKE-NORTHWEST GREENE-WASHINGTON TN-

INCLUDING THE CITIES OF...ONEIDA...LA FOLLETTE...TAZEWELL...

SNEEDVILLE...ROGERSVILLE...WARTBURG...MAYNARDVILLE...RUTLEDGE...

MORRISTOWN...NEWPORT...GREENEVILLE...JOHNSON CITY

332 PM EST SUN FEB 7 2016

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 AM MONDAY TO 7 PM EST

TUESDAY...

THE NATIONAL WEATHER SERVICE IN MORRISTOWN HAS ISSUED A WINTER

WEATHER ADVISORY FOR SNOW...WHICH IS IN EFFECT FROM 7 AM MONDAY TO

7 PM EST TUESDAY.

* EVENT...A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA AND

BRING WITH IT COLDER TEMPERATURES AND CHANCES FOR SNOW. LIGHT

SNOW COULD OCCUR DURING THE EARLY MORNING HOURS ON MONDAY BEFORE

TEMPERATURES WARM UP DURING THE DAY SWITCHING PRECIPITATION OVER

TO RAINFALL. COLD AIR THEN RETURNS MONDAY NIGHT AND REMAINS OVER

THE AREA...ANY PRECIPITATION THAT FALLS AFTER MONDAY NIGHT WILL

BE SNOW. DURING THE EVENT PLACES COULD SEE 1 TO 2 INCHES OF SNOW

WITH LOCALLY HIGHER AMOUNTS POSSIBLE.

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This would be a much better event if not for the nearly inexplicable switch to rain through the day Monday.

 

It also will serve to illustrate all the ways we struggle to get snow here if it switches to rain. The 540 is usually a good indicator of rain/snow at 1000 feet in elevation, less than 540 and it gets greater and greater odds of all snow. The area will be north of the 528 thickness for the whole event. 850s are also a decent indicator of snow being capable of reaching the surface. The 850s will be very cooperative for the entire area, well below 0c. The mid and upper level winds don't even get out of the SW, they are from the West then North West though the event.

 

One day you have OHX talking about snow falling with temps at 43 degrees with this kind of upper level set up, yet every model and forecast says rain.

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Well, it's now only the Central and Southern Valleys that don't have an advisory. This is just my guess (and I could be wrong), but I think that the Central Valley (Knox, Anderson, Northern Blount, Northwest Sevier, Jefferson) will get an advisory closer to the system moving in. The Southern Valley will probably be the ones left out.

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MRX AFD:

 

 

 

SHORT TERM (TODAY THROUGH TUESDAY)... WEATHER THROUGH THE
REMAINDER OF THE DAY WILL BE PLEASANT WITH MOSTLY SUNNY SKIES AND
HIGHS TOPPING OUT IN THE 50`S ACROSS MUCH OF THE AREA. THINGS WILL
QUICKLY START TO CHANGE OVERNIGHT AS A LOW MOVES ACROSS THE GREAT
LAKES REGION AND THE ASSOCIATED COLD FRONT SWEEPS THROUGH OUR AREA.
CLOUD COVERAGE WILL INCREASE AFTER THE SUN HAS SET AND
PRECIPITATION WILL MOVE IN FROM THE NORTHWEST. TEMPERATURES ALOFT WILL
COOL MUCH MORE QUICKLY COMPARED TO SURFACE TEMPS AND THIS WILL BE
THE BIGGEST CONCERN WITH REGARDS TO PRECIPITATION TYPE. IF THE
SURFACE COOLS OFF QUICKER WE WILL SWITCH TO SNOW MUCH FASTER, BUT
IF IT DOESN`T AND WE REMAIN SEVERAL DEGREES ABOVE FREEZING THEN IT
WILL LIKELY BE RAIN. MODELS ARE IN DISAGREEMENT WITH THE
TEMPERATURES NEAR THE SURFACE WITH THE GFS/NAM BEING MUCH COLDER
COMPARED TO THE ECMWF AND OTHER MODELS. THIS HAS LEAD TO A LOW
CONFIDENCE FORECAST WHEN IT COMES TO THE MONDAY MORNING COMMUTE AS
ONLY A COUPLE OF DEGREES COULD MEAN THE DIFFERENCE BETWEEN A WET
COMMUTE AND ONE THAT INVOLVES A COUPLE OF INCHES OF SNOW.
WITH THAT
SATED, WE HAVE GONE AHEAD AND ISSUED A WINTER WEATHER ADVISORY FOR
EARLY MONDAY MORNING THROUGH TUESDAY NIGHT. IF TEMPERATURES REMAIN
WARM ENOUGH THEN PLACES IN THE ADVISORY AREA MIGHT NOT SEE SNOW
UNTIL MONDAY NIGHT...HOWEVER, IF SNOW MOVES IN FASTER OR
TEMPERATURES ARE SLIGHTLY COOLER THAN FORECASTED THEN THE MONDAY
MORNING COMMUTE COULD BE SNOWY IN SOME PLACES.
SO WE HAVE ERRED ON
THE SIDE OF CAUTION AND STARTED THE ADVISORY IN THE MORNING ON
MONDAY. REGARDLESS, THE TEMPERATURES IN THE VALLEY WILL WARM ENOUGH
TO LIKELY SWITCH OVER TO RAIN DURING THE DAYTIME HOURS. WITH THE
STEEP LAPSE RATES AND COLD TEMPERATURES ALOFT, IT`S NOT OUT OF THE
QUESTION TO HEAR A RUMBLE OF THUNDER DURING THE DAY WITH THE
RAINFALL
.
TROUGH WILL REMAIN OVER THE AREA ALLOWING FOR VERY COLD
AIR TO CONTINUE TO INVADE INTO OUR REGION AND TEMPERATURES ON
TUESDAY WILL LIKELY REMAIN BELOW FREEZING FOR MANY PLACES. ANY
PRECIPITATION THAT DOES OCCUR ON MONDAY NIGHT INTO TUESDAY WILL
REMAIN IN THE FORM OF SNOW. QPF DOES LOOK LIGHT WITH THIS EVENT AND
THEREFORE WILL RESULT IN A RATHER SLOW SNOWFALL ACCUMULATION DURING
THE FIRST PART OF THE WEEK.

.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...FRIGID WEATHER PATTERN
REMAINS IN PLACE WEDNESDAY INTO THURSDAY AS ADDITIONAL ENERGY DROPS
SOUTH THROUGH THE BASE OF THE EASTERN U.S. UPPER TROUGH.
TEMPERATURES WILL BE WELL BELOW NORMAL BOTH DAYS WITH MAXES
REMAINING BELOW FREEZING ACROSS NEARLY THE ENTIRE FORECAST AREA ON
WEDNESDAY AND OVER MUCH OF THE NORTHERN TWO THIRDS OF THE REGION ON
THURSDAY. LIGHT SNOWFALL STILL POSSIBLE TUESDAY NIGHT EVERYWHERE BUT
TRANSITIONS TO MORE OF AN OROGRAPHIC SITUATION IMPACTING MAINLY THE
HIGHER TERRAIN OVER SOUTHWEST VIRGINIA AND ALONG THE TENNESSEE AND
NORTH CAROLINA BORDER FOR WEDNESDAY. WEDNESDAY NIGHT INTO THURSDAY
THERE STILL MAY BE A FEW SNOW SHOWERS POSSIBLE IN THESE MOUNTAIN
LOCALES BUT ANY SNOW SHOULD BE OVER FOR THE REMAINDER OF THE
FORECAST AREA. MODELS NOT ENTIRELY ON THE SAME PAGE BUT STILL HINT
AT AN ALBERTA CLIPPER TYPE SYSTEM FOR THE POSSIBILITY OF SOME LIGHT
SNOW AGAIN FRIDAY INTO FRIDAY NIGHT. KEPT SLIGHT AND LOW CHANCE POPS
IN FOR THIS POSSIBILITY. SATURDAY AND SUNDAY APPEAR TO BE DRY AT
THIS TIME AS THE OFFENDING EASTERN TROUGH MAY FINALLY SHOW SOME
SIGNS OF SHIFTING OFF TO THE ATLANTIC.
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Everything about this screams snow as the p-type. Especially with steep lapse rates and heavy precip. There's simply no way so much upper level cold won't transfer down through the column under heavy rates. I've gotten 8 inches of snow at 36 degrees. I've seen heavy snow falling at 42 with good upper level support. 

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Everything about this screams snow as the p-type. Especially with steep lapse rates and heavy precip. There's simply no way so much upper level cold won't transfer down through the column under heavy rates. I've gotten 8 inches of snow at 36 degrees. I've seen heavy snow falling at 42 with good upper level support. 

I know, I absolutely have seen it so many times over the years.  

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