It’s Meteorological Spring! So Let’s Discuss Freezing Rain!

Current Official Hourly Observation (taken at :53 on the hour)

Current Radar Loop

Saturday  Cloudy

Temps Next 24 Hours (auto-updating)

Today is the first day of Meteorological Spring (a/k/a Fake Spring)! So, of course, most of this update will be about Freezing Rain.

Looking back at February, it was wetter and colder than normal. Snow fell on 4 days, for a grand snowfall total of 0.1″. Yes, you read that right. Zero-Point-One Inches. It took four days for us to get:

Only a slight chance of rain very late tonight. Otherwise, expect an overcast Saturday.

Sunday – Rain + Cold Front = Late Freezing Rain & Wintry Shenanigans?  Morning Low 46 / Afternoon High 58

National Weather Service Text Product Display 2014-03-01 06-25-49 2014-03-01 06-27-28

There is a major winter storm brewing . . . to our Northwest. Predictably, the edge of this winter storm will be close enough to us to warrant discussion, but the big impacts are likely to miss us. We think.

Here’s the weather warning/watches/advisories map as of 6:30 Saturday morning. Notice we are not included in any winter watches or warnings. This may change later.

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Sunday Rain

Off & On (mostly “off”) rain is likely Sunday morning into early afternoon.

By mid-afternoon, heavy rain will arrive, and last through the night. The Hi-Res NAM at 6 PM has a good illustration:

Wintry Precip

Most of the time, the freezing line is behind all the rain, meaning the rain pushes through, then the temps drop under freezing.

Late Sunday night or early Monday morning, some models think the freezing line may be in the middle of the rain. Stated another way, we think the temp may drop below freezing while the precip is still here. Check out the Hi-Res NAM Sunday night at midnight:

Don’t fixate just on the freezing line (drawn in white, above). It will have been almost 60 Sunday afternoon, so for any ice shenanigans to happen, we’ll have to get well under freezing, likely 27 or 28 degrees. Rain and 31 or 32 degrees will slick up your deck, mailbox, garden gnome/pink flamingo, a few bridges/overpasses, and areas at elevation (poor Joelton), but it shouldn’t cause a giant mess on the roads.

Here is the GFS Ice/Freezing Rain/Rain/Snow model through Monday at 6 AM:

Because temps overhead are expected to be warmer than temps on the ground, we think we’ll see freezing rain (falls as rain, hits the ground, then freezes).

What we said yesterday is still true today. An ice storm requires a precise alignment of several atmospheric conditions. It is extremely difficult to exactly forecast this event 36+ hours in advance.

Stay tuned. This could become a big deal, or nothing at all.

Currently, we think extreme N and NW Davidson County may see an ice storm. The SPIA Damage Index measures the potential impact of an ice storm on the utility grid:

SPIA Sunday Night:

SPIA Monday Morning:

Fun Fact: Sunday’s storm system is the same one that brought Tornado Warnings to southern California Friday.

Monday – Snow?  Morning Low 25 / Afternoon High 34

National Weather Service Text Product Display 2014-03-01 06-27-42 2014-03-01 06-28-36 

The storm system will be exiting the Middle Tennessee in the morning. A few snow showers may develop on the back side of it, but no meaningful accumulation is currently expected.

Official Extended NWS Forecast:

Screen Shot 2014-03-01 at 6.29.46 AM

Additional information can be found on Twitter @NashSevereWx.