Jump to content
  • Member Statistics

    17,598
    Total Members
    7,904
    Most Online
    PublicWorks143
    Newest Member
    PublicWorks143
    Joined

2/14- 2/16 Winter Storm and Arctic Cold


WestTennWX
 Share

Recommended Posts

.LONG TERM...(Monday through Saturday)
Issued at 440 PM EST SAT FEB 13 2021

Isentropic ascent will be ongoing at the start of the period with
a mixture of snow/sleet/freezing rain early Monday, transitioning
to more freezing drizzle during the day as the better lift moves
northward. However, a shortwave trough with strong diffluent flow
will push into the region Monday evening with precipitation rates
quickly increasing. There is even some negative EPV aloft that
could aid in precipitation rates. With this said, models continue
to trend towards more snow potential in the northwest portion of
the CWA with more ice to the southeast. Somewhere in the middle
could see a combination. Given the potential QPF and good chances
of meeting ice or snow criteria for a warning, opted to go ahead
and toss the remaining areas of eastern Kentucky into the winter
storm watch. The snow could be very wet given the warm nose fairly
close to the 0C isotherm aloft.

Precipitation does look to come to an end fairly quickly Tuesday
morning, but colder air will filter into the region along with
some flurries. A brief lull in the weather is expected fro Tuesday
through Wednesday. Another system will take aim on the area
Wednesday night into Thursday. The ECMWF maintains its colder
solution while the GFS is much warmer. Thus, too much spread to
dive into any details at this point, outside to say there may be a
chance for more wintry weather.
  • Like 1
Link to comment
Share on other sites

I guess MRX is in with the NAM as the warming trend. Though it was actually colder at 18z vs 12z and is on an island with the low track. 

I really don’t know what they look at sometimes. If anyone of the mods went warmer it could be the NAM but they wrote the AFD like several mods have been trending all day.


.
Link to comment
Share on other sites

I haven't had a lot of time recently to follow here. But I just wondered where the current boundary is for the artic air/front that I have seen mentioned? Just looking at the current frontal map, it is difficult to tell exactly. I presume that it is backed up on the plateau area... but, just wondering.

Sent from my SM-G965U using Tapatalk

Link to comment
Share on other sites

National Weather Service Nashville TN
244 PM CST Sat Feb 13 2021

.DISCUSSION...

Ok, here we go getting ready to venture into an upcoming winter
wonderland. Forecast is problematic, to say the least. Biggest
problem is the precip type. It is certainly going to be
sufficiently cold enough to support an all snow event west of
middle TN. Across our Plateau, some warmer air may allow rain to
occur for an uncertain duration. In between, a mixed bag. Details
will follow later in this discussion.

Another cold day today. The freezing drizzle has ended and that
allowed for the advisory to terminate at 18Z as scheduled. Hrrr
does elude toward some patchy drizzle perhaps across eastern zones
late tonight. Other models not quite in line so I will include
this light precip.

On Sunday, temps will again struggle and will only warm into the
upper 20s northwest, to the mid 30s along and east of I-65. By
late in the afternoon we will begin to see the approaching 1st
wave of the winter weather assault.

Sunday evening, the wintry precip will move in. Warm noses are
indicated with a variety of the models. Thus, sleet and freezing
rain will be the main types. Amounts with the 1st wave will not be
too heavy. Looks like mostly sleet across the northwest where
temps will be colder. to the east and southeast however, we will
be looking at between one tenth and two tenths of an inch of ice
by midday Monday.

On Monday afternoon, the second and much stronger intrusion of
wintry precip will arrive. Note that the arctic air at that time
will begin to exert more of an influence across all areas west of
the Plateau. With the depth of the cold air on the increase, the
fcst is looking snowier. Furthermore, with temperatures Monday
afternoon and evening ranging between 17F and 22F in our far
northwest, ratios of a little greater than 10: 1 can be expected
for that area. For that reason, the far northwest snow totals will
reach up to 6 inches.

I will be reissuing the winter storm watch. However, I will need
to segment this product into 3 separate groups to cover the rather
wide range in precip type and amounts.

Across the Plateau, warmer air aloft will lead to warmer sfc temps
for that area. They will still receive some ice and a little snow
but amounts over there will be rather low. For the central areas
including Nashville, we are looking at snowfall amounts of 3-4
inches and also ice accumulation of one to two tenths of an inch.

Note that with this storm system, a high multitude of models
support liq qpf amounts of nearly 0.75". Furthermore, this
significant qpf amount is supported by a rather large coverage
area. This means that this is a rather high confidence event in
that our winter warning criteria is nearly a slam dunk. The
Plateau is the only area where warning criteria may not be met.
You see, that warm nose over the lower elevations, is more in
place at the surface for the Plateau counties. The bulk of this
winter weather system is low level driven. Again, its a little too
soon for the warning, but look for it in the next 12-18 hours or
so.

Look for the snowfall to decrease in coverage from west to east
late monday night and into Tuesday morning, when it finally ends.

In the ext fcst, we may have another round of winter weather Wed
nt into Thursday. Lots of uncertainty at this point. The track
will be critical.

Main temperature points worth discussion, teens for lows Tues and
Wed. Highs will generally be in the 30s through the extended
period.
  • Like 2
Link to comment
Share on other sites

3 minutes ago, tnwxwatcher said:

I haven't had a lot of time recently to follow here. But I just wondered where the current boundary is for the artic air/front that I have seen mentioned? Just looking at the current frontal map, it is difficult to tell exactly. I presume that it is backed up on the plateau area... but, just wondering.

Sent from my SM-G965U using Tapatalk
 

I think its pretty close to the eastern edge of the plateau. Temp dropped from 43 to 36 as I drove from Oak Ridge to Mossy Grove (just south of Wartburg). 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...