You may – or may not – have read the updated forecast over on wdam.com, but here is a more technical and detailed look at the potentials and model guidance.
Confidence continues ot increase that a dangerous icing event is about to roll through South Mississippi. The model guidance – as well as the NWS – continues to show a potential for a crippling ice storm for sections of the area.
So far the Freezing rain “bullseye” looks to be to the west of I-59, but depending on how thigns line up during the next 24 hours, that may end up closer to Hattiesburg and Laurel
Latest guidance
The 18z data has been in, but the 00z data is just starting to come in and it features new data from the *checks Twitter* Hurricane Hunters.
The models are hungry! Feeding them some valuable dropsonde data today to help everyone sort out this mess. Scheduled for 20Z takeoff. pic.twitter.com/8eeuK7lomY
— Jeremy DeHart (@JeremyDeHart53d) February 14, 2021
Yes. The Hurricane Hunters were out in the Gulf today. Hopefully any data they gathered will help the models, starting with the 00z runs, get a better handle on how things will play out. So far, here are a few takeaways from the new data
Thundersleet
Probably the best weather term for naming a Heavy Metal band looks like a possibility on the 00z data from the NAM computer weather model.
The sounding data show an elevated unstable layer that may lead to differentiation within the cloud and the potential for a few rumbles of thunder…. While temperatures are near or below freezing in the lowest level of the atmosphere. That may lead to the potential for thundersleet.
Pine Belt Pivot Point
Latest data from the NAM computer model and the HRRR computer model both show that the central sections of the Pine Belt will be the pivot point as the front slide through.
Notice that the temperature between Hattiesburg and Laurel doesn’t change much until the very last frame of that animation. On the light blue side, it is almost all freezing rain the entire time. Ont eh dark blue / green side it is rain changing to freezing rain.
If the pivot point changes from where model guidance is showing it and it moves as little as 10 to 15 miles to the east, it would mean full-on freezing rain nearly the entire time for both Hattiesburg and Laurel. While if that point moves back west, it would mean a delay in a change-over to freezing rain by up to one to two hours – limiting the amount of accumulations (and thus the threat for downed trees, power lines, power outages etc).
So this is a very ‘on the line’ forecast.
So far, this is how it looks
To this point, model data continue to show the colder air – currently parked to our west and northwest – oozing down while precipitation moves into the area. The cold air is now slated to show up mid-morning for most of the area.
The graphic above shows the comparison between all of the available model data for freezing rain accumulation. You can see a fair amount of variability when trying to nail down the fringe areas that may see a light glazing… But the “bullseye” of higher icing looks to be along and to the west of I-59 and back to the NW about 30-40 miles.
That above graphic is a quick glance guide, and can’t be used for specifics, but hopefully it highlights the point that areas within or near that ellipse are the areas of greatest concern for the highest totals of freezing rain in Mississippi.
What to expect
Not much has changed here. Expect power outages, trees down, branches down, impassable roads. Followed by very cold air for our area taking hold on Monday night once the precipitation comes to an end.
If you have to be somewhere Tuesday morning, I would recommend being there by Monday at noon. And where ever you are Monday at noon, I would prepare to be there until Tuesday at noon. Perhaps even until Wednesday at noon.
After precipitation comes to an end, we may have a “flash freeze” event where all of the liquid water left over after the precipitation ends, freezes. And it does so before it can evaporate. That means any area that didn’t get freezing rain and sleet, but just liquid rain, is in a situation where there may still be ice on exposed surfaces.
On top of that, the high temperatures on Tuesday may night be high enough to melt and evaporate all of the ice. That means anything that is leftover will re-freeze Tuesday night and into Wednesday morning.
Forecasts by area
Here is a breakdown of the forecasts by County for Monday:
Northern counties
Simpson County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows below 20 degrees
Smith County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows below 20 degrees
Jasper County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows below 20 degrees
Clarke County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet showers coming to an end
4pm – Some light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows below 20 degrees
HWY 84 Corridor
Lawrence County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet and ice crystal showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows below 20 degrees
Jefferson Davis County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows below 20 degrees
Covington County
7am – Light rain begins to fall.
10am – Rain, changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Jones County
7am – Light rain begins to fall.
10am – Rain, changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Wayne County
7am – Dry and cold.
10am – Rain, that quickly changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Some lingering sleet possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
HWY 98 Corridor
Walthall County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet and ice crystal showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Marion County
7am – Light rain begins to fall. Will turn to freezing rain quickly
10am – Freezing rain, now mixed with sleet, continues
1pm – Sleet and ice crystal showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Lamar County
7am – Light rain begins to fall.
10am – Rain, changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Forrest County
7am – Light rain begins to fall.
10am – Rain, changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Perry County
7am – Dry and cold.
10am – Rain, that quickly changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Greene County
7am – Dry and cold.
10am – Rain, that quickly changes to freezing rain, continues to fall
1pm – Freezing rain showers coming to an end
4pm – Some lingering sleet possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
HWY 26 Corridor
Pearl River County
7am – Light rain begins to fall.
10am – Cold rain continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
Stone County
7am – Light rain begins to fall.
10am – Cold rain continues to fall
1pm – Freezing rain showers coming to an end
4pm – Drying out, lingering light ice crystal flurries possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
George County
7am – Light rain begins to fall.
10am – Cold rain continues to fall
1pm – Rain showers coming to an end
4pm – Some light sleet possible
7pm – Precipitation has ended, very cold air filters in with overnight lows around 20 degrees
The Bottom Line
Not much has changed here.
Be prepared for the potential for wintry precipitation, followed by some pretty cold air. Travel will be difficult Monday before noon. Places will be impassable by Monday afternoon – especially north. And, for some places, it will be almost impossible to drive anywhere overnight Monday and into Tuesday morning.
The good news is that by Tuesday afternoon, things will start to melt and temperatures will be above freezing – barely. And you may be able to get some places. Folks in rurl areas and along county roads that are well shaded will likely still be stuck.
The bad news is that anything that doesn’t evaporate, will likely re-freeze overnight Tuesday and into Wednesday morning. That means another game of “be somewhere by Tuesday at sundown that you are comfortable being until Wednesday at noon.”
But by Wednesday afternoon, we will be back above freezing for a while. And life will get back to normal.
