Category: Forecast Models

There’s been a tremendous amount of buzz concerning the late week winter storm, and for good reason.  This will be a doozie for some (perhaps many) folks.  While most data keeps this storm too far south and east for a big snow for Hoosiers, it’s wise not to write this storm off at this juncture.

A latest scan of the GFS ensembles show 9 of 21 members suggest snow impacts central IN Thursday night.

Source: Weatherbell.com

While we can’t show them here (due to licensing issues), we note 19 of 51 European ensemble members also agree on snow prospects for southern/ central IN.

Experience here (and during my time in the mountains of east TN) suggest time and time again that when surface lows track through the TN Valley, you’ll see a reflection of that low track west of the spine of the Appalachians before the new primary low forms east of the mountains.  This takes place due to the natural impact of downsloping off the Appalachians.  (We’ll bore you with the fascinating impacts of upsloping and downsloping at another time).  🙂  Is that far enough west to provide the “snowy goods” to central IN?  Sometimes yes, and sometimes no.  We’ll continue to keep a very close eye on things as we rumble closer towards late week and we suggest you do as well.

In the near term, challenges also abound.  We still favor a swath of 2-3″ snows through the I-70 corridor tomorrow night-Wednesday morning.  Upper level energy and the higher ratio snow should fluff those amounts up, despite current data tracking amounts south.  We’ll keep a close eye on 00z data.

Much more later!  Have a great evening!

It’s a busy time in the good ole (cozy) forecast office these days as we track (2) notable winter events this week.

Time Line:

• 1st event: Tuesday night-Wednesday
• 2nd event: Thursday night-Friday

12z data is in and has been growing increasingly snowy for Tuesday night and Wednesday for a widespread portion of the area.  At this distance, a “plowable” snow appears likely and we’ll fine tune specific numbers as time draws closer.

12z GFS ensemble members show very good agreement on the snow event ahead Tuesday night-Wednesday. Source: Weatherbell.com

Set-Up:

We expect upper level energy to dig southeast Tuesday morning and “slow” just enough to allow surface low pressure to develop Tuesday afternoon across southern MO.  The surface wave will lift east-northeast into the lower Ohio Valley Wednesday and should spread a widespread swath of snow across central IN.  In looking back at similar events in the past, we note that models usually continue to trend “snowier” with these type set-ups as time draws closer.  This will likely be a rather impactful event, likely greatly hampering the Wednesday morning commute.  Stay tuned.

Just as we begin to clean up from Wednesday’s snow storm, eyes will shift to what may lie ahead in the Thursday night-Friday time period.  The big question that remains with our second storm is the northward extent of the significant precipitation.

Individual ensemble members are much less in agreement when it comes to our late week winter storm threat. Source: Weatherbell.com

The European ensemble look at Day 5 has to make winter lovers smile from the southern Plains into the East. Source: Tropicaltidbits.com

Set-up:

Surface low pressure will develop across OK Wednesday evening and track ENE Thursday into Friday.  The overall pattern supports a significant winter storm late week that will impact a widespread portion of the country.  Looking at the big picture overview suggests we should see a winter storm spread significant snow (and ice for some) out of the central Plains, into the Ohio Valley and on into the Mid Atl and Northeast region.  Of course we know no storm is alike, but leaning on past experience would suggest our second storm comes north a couple “clicks” in the days ahead.  That said, there’s no doubt the northward extent will be limited by the blocking high (a key component to supplying the cold weather “goods”) to the north.  Our advice at this point is to stay tuned closely to the Thursday night-Friday forecast and understand a significant winter storm is a good bet for at least portions of the region.  We’ll have to fine tune the specifics as we move forward.

At the end of the day, hopefully most are realizing this winter, though late, has a lot of “winter” in it.  We’re now dealing with our second surge of bitter arctic air in as many weeks and moving forward, the stormy pattern will continue to rumble through the upcoming 10-14 day period.  This will continue to make-up for the slow start to the snow season.

Looking ahead, given the weakening Nino and a number of other factors, there’s plenty reason to see busy wintry times continue as we rumble through the 2nd half of winter.

Giddy up!