If you're a #BOTS fan then you're going to love the next 3 weeks!

Good news #BOTS fans! Just about all of the wx computer models are showing a very active storm track through the midwest and Ohio Valley. Buckle up! It's going to be a fun ride. We'll start out with some light snow showers and flurries tomorrow on 1-7-24. After that, the fun and games begin.

Right now, the cold air and /or the PV (Polar Vortex) is split into Siberia and Canada. Check these out: (The pink and purple colors represent the coldest air.)



Temperatures will stay close to normal until January 13th and then the polar vortex looks move into town around the 15th.


Take a look at the CFS forecasted temperature for January 19th. (-9F)


The cold air looks like it will be in place until 2-7-24. After that, we return to our average temperatures for February. 

On the flip side, those of you in the south, as in southern Texas, Louisiana, Arknasaw, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina and Virginia will see severe weather with the possibility of damaging winds and tornadoes between 1-8 and 1-9. 

So how do things look for Bloomington, Indiana? Well, I have my eyes on January 13th. This is NOT a forecast because it could end up being rain or clear skies but look at this! (INTENSE heavy snow *if* it were to happen according to the GFS)


Today through January 19th animation:


The Canadian model has more rain changing-to-snow type systems.


Also, it's interesting to see the European model agree with the GFS model on the January 13th storm.



Here is the latest analysis from the National Weather Service:
National Weather Service Indianapolis IN
313 PM EST Sat Jan 6 2024

.Key Messages...

- Drizzle/patchy fog through the rest of the afternoon.

- A weak system tonight will bring additional light snow with
amounts up to an inch north of Indianapolis.

- Few changes to forecast with storm system Monday night into early
Wednesday; primarily rain and gusty winds expected much of the
event, with a brief burst of light snow accumulations possible at
the onset and ending Monday night and Tuesday night. Impacts to the
Wednesday morning commute possible.

- Yet another strong winter storm is possible in the Midwest late
next week into the weekend. Much too early for details but continue
to watch for possible impacts.

&&

.Short Term...(This evening through Sunday)
Issued at 312 PM EST Sat Jan 6 2024

Rest of Today.

Lingering low clouds and abundant near surface moisture has led to
occasional drizzle with lowered visibilities across central Indiana.
Temperatures at Indianapolis have only varied by 3 degrees between
31 and 34 since midnight and with sunset approaching, not expecting
any more than a 1 degree increase through the rest of the day.  With
surface temperatures just above freezing, there haven`t been any
impacts from the drizzle but will continue to monitor this ahead of
the loss of the minimal daytime sun. ACARs soundings combined with
IR satellite show that the top of the cloud layer lacks ice which is
leading to the drizzle vs snow as seen earlier.

Tonight.

This cloud layer will begin to deepen later into the evening and
overnight hours with ice nucleation expected to begin around 7-8PM
which will coincide with a weak wave that is expected to move across
the northern counties to bring another quick hitting snow. There is
little to no vorticity with this system with snow being driven more
by lift within the 600mb to 850mb layer which is much less
substantial than what was seen during the overnight hours last night.

This snow should generally remain isolated to points along and north
of I-70 with amounts no greater than an inch for most spots with
most areas seeing closer to 0.50". Temperatures tonight will remain
near steady state with lows in the low 30s with westerly winds
beginning to strengthen as pressure gradients briefly tighten across
the forecast area.

Sunday.

Similar weather is expected for tomorrow with some lingering low
clouds in the morning with drier air gradually working in.  Non-zero
instability will arrive by the afternoon with dry adiabatic lapse
rates up to the top of the boundary layer at around 3kft with drier
air above it. This could have led to some brief convective snow
showers/light rain if the top of the cloud layer had been a bit
cooler combined with a weaker cap at the top of the boundary layer,
but with those limitations expect just a few areas of heavier
sprinkles or perhaps light snow mid to late afternoon with much of
the precipitation ending by noon.

&&

.Long Term...(Sunday night through Saturday)
Issued at 312 PM EST Sat Jan 6 2024

Very active long term period across central Indiana, with at least a
couple of impactful systems likely for the region.

The first round of the week comes Monday night into early Wednesday.
A very strong low pressure system will pull quickly northeast out of
the Texas Panhandle into central Illinois and northwest Indiana late
Monday into Tuesday evening. Ensemble guidance is very well
clustered with a low track near or just northwest of the northwest
corner of the forecast area, which will keep central Indiana in the
warm sector and all rain for the bulk of the event.

However, Monday night presents an opportunity for a quick burst of
accumulating snow on the leading edge of the precipitation, despite
borderline near surface temperatures - forecast profiles show a deep
near-isothermal layer near or just below 0C, and with the onset of
strong frontogenetic forcing at the nose of the low level jet Monday
night, dynamic cooling may offset midlevel warm advection for a few
hours either side of midnight and allow for a burst of briefly heavy
snow to accumulate, potentially up to an inch or two, primarily from
Indy northward.

However, strong low and midlevel warm advection as we approach
daybreak Tuesday will rapidly produce a changeover to rain, with
rain continuing through the day on Tuesday. Precipitable water
values continue to exceed climatological 90th percentile much of the
event, with probabilistic guidance showing rainfall amounts in
excess of a half inch a virtual certainty (90%) and in excess of an
inch a significant likelihood (50-60+%), which may put a slight dent
in the longer term drought conditions. Some minimal upright
instability is present in some forecast profiles, and given the
strong dynamics present throughout the depth of the troposphere,
some elevated convection/embedded thunder cannot be ruled out, but
remain uncertain and will not include for now.

As the low continues to wrap up and move rapidly northeast into the
central Great Lakes, onset of cold advection Tuesday night will
promote a potentially rapid changeover back to a mix or all snow,
with potential for another brief burst of accumulations in the
plentiful wraparound moisture before precipitation tapers off late
Tuesday night into Wednesday morning as the column dries from aloft.
Will have to monitor for possible impacts to the Wednesday morning
commute.

Some of the guidance suite produces a weak clipper-type system
moving through the Great Lakes late Thursday into Friday, with
additional potential for light snow or a mix across portions of the
area, particularly north.

Models then show another strong low somewhere in the region Friday
night into Saturday, but extremely large ensemble spread and model-
to-model inconsistencies give very low confidence on precipitation
types and amounts - but another round of impactful precipitation is
on the table.

It remains very important to avoid keying in on one model, one run,
or one cherry-picked extreme solution, particularly for the late
week system, and to instead monitor trends and updates from trusted
sources as the week wears on.
Enjoy and have a great weekend!

















No comments:

Post a Comment