Winter Weather Threat for Tuesday 2/24/15

Hey Everyone,

I know a lot of you guys have been wondering what our chances are at seeing some winter weather on Tuesday. Some of the major media outlets have put chances of winter weather on their 5 day forecasts.

Im gonna be blunt and to the point from what I have seen today in every possible weather map and model there is in existence.

Facts
There is a chance of Winter Precipitation on Tuesday morning and through the afternoon.
There is a ton of model uncertainty in regards to the amount of moisture and temperatures during the day on Tuesday.
The only model that is depicting any kind of significant event for Tuesday is the current 18Z NCEP NAM Model.

Not a Forecast! Model Guidance Only!

Above you see the NAM simulated radar for 4AM Tuesday Morning. It is depicting a large area of Snow across most of the State. I am very, very suspect of this for a multitude of reasons. I will list out below as we go below. See the next Photo and below for a description.

This is whats called a SREF Plume. SREF stands for a Short Range Ensemble Forecast. Each color is representative here of precipitation type in Columbia. (Green-Rain, Red-Freezing Rain, Blue-Snow, Pink-Ice,Sleet) At the bottom you will see a date and time stamp in Z time. You will notice around 12Z on Tuesday which is 7AM the snow chances jump to 44.89%. then later in the day the freezing rain chances increase to 59.6%.

Now most of you are thinking wow, looks like really good chances right ? Wrong.


Even though the chances are there, I will go to the next SREF Plume which is showing the amount of QPF (Quantitative Precipitation Forecast) which is measured in inches.

 
As you can see above on Tuesday the total QPF is forecasted to only be around .06" which isn't hardly anything.



With all of this being said, yes there is a legitimate chance of snow on Tuesday however my confidence for tonight will remain quite low given everything that I have looked at. Below I will show the official Snowfall and Freezing Rain Forecasts from the National Weather Service.

Both of these maps are showing the probability of each between tomorrow night and Wednesday at 7:00 PM

This will have to be monitored very closely over the next 12-16Hrs to see if any kind of model agreement can come into place. That would make me a lot more confident in seeing Winter Weather in South Carolina.

Hope everyone has a good night! Expect something tomorrow !


- Chris

Winter Storm Octavia

Hey Everyone,

Im back here on my blog format for tonight to lay out everything in a much better format versus Facebook. First off, I wanna say thank you everyone for all the positive feedback I have gotten. I have managed to get almost 20,000 page views on my Facebook Page in the last 4 days.

Getting on with the Nuts and Bolts of this impending Winter Storm.

It looks very likely that most of South Carolina will experience Winter Weather.

When: Monday Evening through Wednesday Mid Day.

Where: Will cover that below but areas North and West of I-95 should pay close attention.

What will Fall? A little bit of everything. Rain, Freezing Rain, Sleet, and Snow.

Impacts : Hard to say for now but there could be significant impacts such as dangerous slick roads, extended power outages, falling trees, And ice on everything imaginable.

Setup:

During the day tomorrow an area of Low Pressure is expected to begin to develop over Eastern Texas and Louisiana this area of Low Pressure is then expected to move ENE over the Deep South and by Monday afternoon will make its approach on South Carolina. 

I am not expecting anything significant until after 7PM Monday for any portion of South Carolina and Western North Carolina. It appears that moisture will move into the area before then but, due to low dew points and some really dry air in place, it will take a few hours to get the atmosphere wet enough to support precipitation falling to the ground. 

There has been some uncertainties in regards to the exact track of the Low Pressure. This is going to be pretty important. A jog 75 miles each way could mean a Winter Wonderland or just a soggy, raw day. I am hoping that the models come into better agreement over the next 18-24Hrs so I can have a better idea of what to expect. 

Miller A or Miller B ?

Below this paragraph is the 18z GFS Model Run from today and it has hinted at this storm phasing and becoming whats called a Miller Type B Storm. There is also a Miller Type A Storm which has one centered area of Low Pressure that usually remains offshore. Im sure you all are asking yourselves What is a Miller Type B Storm ? Miller Type B storms usually involve the following during Cyclogenisis. (An area of Low Pressure Forming and Strengthening)

• 2 Low Pressures Involved (One Primary Low, and a Secondary Low)
• The Secondary Low develops along the coast as the Primary Low over Land weakens.
• Usually occurs in situations where CAD is in place. (Cold Air Damming or "The Wedge)
• The Secondary Low can become quite intense, quickly. 

Again this only a model run and not a Forecast. 

What to Expect over the duration of the event:

This will likely start out as all snow on Monday evening after 7PM and as Isentropic Lift increases we will see a "nose" of warm air overrun the cold air at the surface. This will result in a change over to Sleet and/or Freezing Rain on Tuesday morning. During the day on Tuesday as temps warm I would expect a changeover to all rain for a few hours before once again, turning back over to freezing rain. This will remain the same until early Wednesday as the system strengthens off the Coast. If this happens, we would see cold air wrap around the Low Pressure and have yet another changeover to all snow. With the Cyclogenisis of the storm there could be a band of heavy snow that sets up somewhere in North and South Carolina.


Other Models: 

All of the other models are in agreement in Winter Precipitation but there a few differences in position, timing, and Precip Type. 

Locations:

For now, I have listed below the official National Weather Service's map of Freezing Rain accumulating greater than .01" see your area with the corresponding percentages.

Until models come into better agreement I am not going to throw any specifics out there. We will save that for tomorrow. 

 

Accumulations:

Given the model uncertainty as of now I cant say for sure who is going to get what and how much of it. Areas that do get the winter precipitation could get upwards of .10" of Ice and 1" of Snow.

In Closing:

I wouldn't be surprised at all for the National Weather Service to issue a Winter Weather Advisory or Winter Storm watch by 7PM tomorrow given the current information. I will be watching this like a hawk tomorrow and will do another write up tomorrow evening. Hope everyone has a great evening and be sure to check back tomorrow!


- Chris

Something In The Making ?

Hey Everyone, 

***Note: If you do not read this entire article you will miss key information***

I know I haven't posted anything in the past few days and for many of you guys, this blog may be new but, I use this format when I need to convey a message a little easier. Facebook limits you so much on how you can deliver a message to your audience. Also just a few other things for all of my new followers.. 

1. I dont post everyday (Obviously Haha) All mainstream outlets do a good enough job for the most part in delivering what the high and low temperature will be 3 days from now. I find interest in the "big thing". I could write some bland numbers with a percentage but, I would drown myself into every other method of getting your weather information. I like to be different. 
2. I do all this on my own time. Not for monetary gain. I pay for all of the data I receive. 
3. An average day of weather models is something like this to me. 

• GFS Models update 4 times per day. So just within the GFS in 24 hours I see 4 distinct model runs. Out to 384 Hrs 
• Euro Models update twice per day. Out to 384 Hrs 
• Canadian Models update twice per day. Out to 384 Hrs 
• NCEP NAM updates 4 times per day.  Out to 84 Hrs
• HRRR (High Resolution Rapid Refresh) - Every Hour! But only goes out to 18 Hours. 

And that's not even all of the data I have access to. 

To put it in perspective with this upcoming storm I am getting extremely interested in, in a 24 Hour period, I will able to see up to 36 different, distinct model solutions.

In other words, Its a lot of work! I very easily put 40 hours a week into my weather forecasts on top of working as much as 65 hours in my career which for those that do not know is a firefighter. 

I have been looking at data for 5 hrs non-stop as of right now and trying to come up with an educated opinion on what is going to happen this Friday. Wait, Friday ? What happened to Tuesday night? The area of Low Pressure is just going to move entirely too far north for us to see any winter weather. 

So without further hesitation, lets talk about Friday....

We have been in a pattern for most of the winter that has involved a big trough (Dip) in the Jet Stream over the Eastern half of the country and where there is a trough, there must be a ridge of mainly dry, warmer than normal temperatures. (See California's Drought)

Anyways this week will be no different. This week most areas north of Pennsylvania will see temperatures below zero at some point and we will see temps on average around 10 degrees below the norm.

Wednesday and Thursday a 500MB Shortwave will slide east from Texas and into the Gulf Of Mexico. This "disturbance" or piece of "Energy" as what it is frequently referred to as will help encourage a broad area of Low Pressure to develop in the Gulf. At the same time a large area of High Pressure should be in place over the Great Lakes Region and will give us a nice shot of cold air coming down the eastern seaboard. See Photo Below for better reference.

Notice the big dip over Louisiana and Texas. This is what a shortwave at 500MB looks like. Its called a "Shortwave" because of the dip or sharp cut in the longer wave. 

Now here is where it gets tricky 

The models are literally all over the place at times over the last 4 days. Yes I have been watching this for 4 days and haven't mentioned it. . The GFS has been trending more towards snow over most, if not all of South Carolina late Thursday night into Friday morning. The Euro also is in agreement but, it has not been in much of a consistent trend over the last few runs. The GFS was in the same boat on the 29th and the first run on the 30th but since has gotten a solid trend going. The next 48-54 hours will really "tell the tell". 

This is what the GFS has done for Friday morning since the 28th. Each pic is a different Model Run. Notice how some model runs has snow across all of the State and some doesn't have anything ?  Yea...The struggle is real. 

This time next weekend we could be seeing white or it could just as easily be a total bust and not even a drop of rain. Its early. Way Early. But the trend is there. All of the "players" are in the right places for us to see some wintery weather. 

One of the biggest factors will be ....

I have made 3 different scenarios. Each comes with its on set of outcomes given that everything else falls into place. 

1. Scenario 1 would likely give us the most precipitation and in this case, snow. However I haven't seen any model that has a "closed" area of Low Pressure moving within 75 miles of Charleston. 
2. Scenario 2 would still give us a chance at seeing snow over most, if not all of the State. However given its distance offshore, moisture would be more limited and any event would have a shorter duration. 
3. Scenario 3..... Most of us, me included will just be mad as we enjoy a dry Friday.

What do i think is the likely Scenario if this actually happens right now at 1:35 on January 31st?

 If you put a gun to my head right now I would say Scenario 2, if it were gonna happen based on current data. 

I Know Everyone Wants To Know:

If we get snow, how much are you thinking we will get? 

And here is where I get really really frank. Its foolish to think snow accumulation totals 6 days in advance, I refuse to even discuss snow totals until we get inside a 84 or 72 hour-ish window. 

The GFS was the Champion for the Blizzard last week in New England. Even though the Euro was the first to show the potential for a blizzard, which was inside of a 5 day window. Things can change very quickly either way. So for now, we can save the "how much" talk until about Tuesday night or into the day on Wednesday. 

In Closing Somewhat, 

I was planning on getting this out before noon but the new GFS model data started to come in so I waited 90 minutes for it to completely load up and get the newest information possible. And guess what, the trend is continuing! See the Gif below of the brand new GFS model run as of noon. 

This newest Run (12Z) is keeping most of South Carolina seeing some sort of Winter Precip between 06Z and 18Z on Friday.

Also below is whats called a meteogram. Call it a "Snapshot" of the next 7 days worth of weather for a given location. This is of course for Columbia. See below the picture for description on what it exactly means. 

1. T2Max - This is what this model run thinks the maximum temperature for this date and time is. This is measured as 2 Meter, or 2 meters off of the ground. 
2. T2Min - Exactly the same as the max only the minimum temperature. 
3. 32 Degree Line - This one's easy, right? Above the line is above freezing, below is well, below freezing.
4. Total Precipitation - This is the total amount of precipitation during the given period and each box represents 12hrs of precipitation.
5. Total Snow - I need not explain.
6. Just the same as 4 but, in a bar graph format showing how much precipitation over a 12hr period.
7. Date and Time: It is formatted like so. 01/12, whereas 01 indicates date, February 1st and time is in Zulu format or 12Z. See the chart below if you're not familiar for quick reference. 

Alright, 

Finally the End. Hope this begins to shed some light on what I have been looking at and thinking for the upcoming week. I will go on the record and say that as of right now, I am not forecasting snow. Its just too early and I still have marginal confidence in this. Gimme 54 hrs and Ill have a better feeling about it...

As always thanks for reading, share with your friends and follow me on other social media outlets I have listed below. I will be glad to answer any questions other than how much snow are we going to get. 

Twitter: ChrisJacksonSC

Instagram: Chris09Jackson

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Till Next Time Friends!

- Chris 

8PM Weather Update. 1/11/2015

Hey Everyone,

I have been looking over all of the weather data for the last couple days trying to get a grasp on this possible Freezing Rain event on Wednesday Morning. Note that I said Freezing Rain. Snow isn't on the table for Wednesday Morning, sorry but, just telling it like it is. I also decided to make a post on my blog here so I can better convey my message and add graphics into my post. I will also say that there is an outside chance at some snow on Thursday as Low Pressure will move Northeast off the Coast. Anyways, lets get into it.

This is the official National Weather Service Freezing Rain Probability Forecast. Notice the distance from 0-70% is less than 75 miles.  This is the probability of at least .01" of Freezing Rain. 

Tuesday Night and early Wednesday morning, an area of high pressure in the Northeastern part of the Country will give us the "wedge", a layer of cold air at the surface.

The million dollar question is a two part question,

A.) How far south will the cold air make it by the time the moisture arrives ?
B.) How much moisture will we have ?

Here are my thoughts,

Timing and Temperature

Wednesday morning I think there will be areas of freezing drizzle and maybe light rain. However, I do not foresee this being anything significant in South Carolina. However folks in North Carolina, may be in for a little more ice. Areas from Winston Salem over to Raleigh and down to Fayetteville could see more significant ice that could cause issues.

By Wednesday morning in the Columbia area temps will be flirting with 32 Degrees and predicting where it will be freezing and where it wont is next to impossible. It all depends on how far south the cold air makes it and that is yet to be seen. Below is the latest GFS model run and note how at 7am Wednesday morning they have Columbia at 33 degrees and surrounding areas at 32 degrees. Its going to be that close and I wont know until as soon as maybe 12-18hrs in advance. So Stay Tuned on that.

7AM Wednesday Morning Surface Temps. This is a model not a forecast. Note the "U" Shape feature in Southwestern Georgia into Eastern Alabama. Thats how far South the "Wedge" will come down the eastern Appalachians. 

How Much Precipitation

This storm system will not provide an abundance of rain during the time frame that we will be near the freezing mark. This is why I am not foreseeing anything significant for Wednesday morning. An area of Low Pressure will develop and move off our Coast by later in the day.

My Prediction

I think late Tuesday night and into early Wednesday morning there will be a large area of light freezing precipitation in the area and then will change over to rain during the day on Wednesday sometime in the late morning hours till around lunch time.

As of now I do not see any need to go out and do the bread and milk grocery store scramble.

All in all, whatever we get I do not see this being a significant winter weather event in the Midlands of South Carolina.

For Reference I have listed 2 more photos below with captions.

This is the Sperry-Piltz Ice Accumulation Index. This is a good ball park idea of what type of impacts you can expect given the accumulation amounts of Freezing Rain and with accompanying Winds. 

This is a great example of how different percipitation forms. This is a visual representation of what ive been saying for the last few days. 

In Closing,

I will be doing a forecast every day this week due to the impending storms and updates as needed. There is also a chance of "something" Thursday evening but, I am not even ready to talk about that. Hope everyone has a great evening and thank you all again for all the support.

Chris