2014-2015 Winter Breakdown

As fun as they were at first, with spring just around the corner and temperatures reaching the 60's, we can finally put behind us all those walks across campus filled with snow and ice, snowball fights, and anxiously waiting to see if classes would be cancelled. Before we do, let's look back and reflect on the harsh winter we experienced this year. Here is a breakdown by storm.

Winter Storm Juno: Juno was our first storm of the season with a major impact. Officially, Reagan National received 0.6 inches from the storm, Dulles 2.0 inches, and BWI 1.0 inches. The snowfall totals across the area ranged anywhere from 1-4 inches. Fairfax actually received 4.3 inches because heavier snow bands set up overnight. This storm surprised most of our region. At first, this storm seemed to be a simple clipper that would bring in could air and set us up for a couple inches of snow. The forecast for this storm changed dramatically on Sunday night when the storm track shifted north and transferred it's energy into a huge storm that formed over the Ocean. This set up a situation for a two part storm. The first part of the storm was the clipper. The storm shifted north which meant temps ended up being milder than expected. This resulted in less accumulation in some areas than expected out of the first part of the storm. The second part of the storm. There was a lull in the precipitation between the first half of the storm and the second half of the storm as the clipper dissipated over us. The second wave began Monday night into Tuesday morning as the coastal storm developed.

The very impressive Wind Field of Winter Storm Juno shows how powerful it really was

How did we do on our prediction for this storm? Although it was a complicated forecast, we were pretty much spot on. We predicted 2-3 inches in Fairfax. Because of some heavier bands in the first part of the storm, we observed totals slightly higher than expected here in Fairfax. We also mentioned that some areas may not get much of anything . Overall our prediction was very accurate.

Winter Storm Octavia: Octavia was our second major storm of the season. Officially, Reagan National Airport received 4.7 inches, Dulles 3.9 inches, and BWI 3.8 inches, This storm came up from the south and dropped 3-5 inches of snow across our region. Temperatures were below freezing throughout the entire storm which resulted in a lot of accumulation

A look at the aftermath of Winter Storm Octavia at the White House

Did we get this storm right? We were accurate on some aspects of this storm. Just like we predicted, this storm provided significant accumulation that caused major delays and cancellations. There were two main aspects that we did not predict. The first aspect that we did not predict was there was a dry slot in this storm. We predicted heavy bands of snow between 10 PM and midnight. During this period there was less moisture than expected so snow totals were lower than we expected in the morning. We also predicted that this would be a powdery snow that would accumulate quickly. When temperatures are as cold as they were during this storm, powdery snow is likely. That was not the case for this storm and that resulted in lower than predicted snow totals. Overall we did get the timeline correct but we were a little lower than our range. We predicted snow totals would be more in the 5-8 range with anything below 5 inches a bust. This storm did under perform a little bit but it still caused a significant impact.

Winter Storm Pandora: Pandora arrived on the night of Saturday February, 21st. Officially, Reagan National Airport received 2.6 inches, Washing Dulles International airport 8.9 inches (a daily record), and Baltimore Washington International Marshal Airport 6.3 inches.. This storm ended up having a pretty significant impact on this area. Areas to the north ended up getting more snow as predicted.

Winter Storm Pandora caused drivers to slow on I-81 near Winchester

How Did we do on our prediction for this storm? Although it was a complicated forecast, we were pretty much spot on. We predicted 3-6 inches in Fairfax. Snow totals in Fairfax ranged everywhere from 3 inches to 8 inches in some spots. Southern Fairfax county got around 4 inches where areas in the western part of the county received around 8 inches of snow. Our forecast was pretty accurate for this forecast. Some areas ended up with a little more than expected but overall our forecast was pretty much spot on for this storm.

Winter Storm Thor: Winter Storm Thor arrived on the night of Wednesday March 4th and went into the day Thursday. Temperatures during the day Wednesday were still in the low 40's so the storm began as rain. The storm quickly switched over to a mix and then to snow over night Wednesday into Thursday. The snow began falling rapidly as very heavy bands came across our region. This was quite a storm for March, Anywhere from 4-10 inches fell across our region during this storm. All three airports established new daily snowfall records.

Reagan National Airport- 4+ inches - setting a new daily record for march 5, passing the previous record of 4.4 inches set in 188

Dulles International Airport- 9.4 inches, a record for March 5 crushing the previous record of 1 inch from 2001

Baltimore-Washington International Airport logged 6.2 inches, beating its record for march 5 of 4.0 inches from 1902.

Near white-out conditions on the National Mall during Winter Storm Thor

So how did we do? Once again this storm behaved pretty much how we thought it would. The uncertainty in this forecast was that it was on the backside of a storm. It started off as rain and we received the back end of it as it turned to snow. The models for this storm were in disagreement on when this changeover would take place. The switch happened pretty much when we expected it . Some bands dropped heavier snow than we thought. The city of Fairfax received 6 inches of snow. Overall this storm behaved exactly how we predicted it and the snow total in the city of Fairfax was right in the middle of the 5-7 inch range that we expected.

So how did we do overall? For the most part we got the forecast relatively within the range of snowfall for the entirety of major storms that came through the DC area. There were a couple that were troublesome due to their last minute changing nature. In the end though forecasting these storms is always a learning experience and a task that is tough as it is enjoyable.

In the beginning of the season, James Luehrs did a pre-winter forecast where we gave a preview of this Winter to come. So how did he do with that seasonal forecast prediction?

(Note: All of these totals and averages are for Fairfax, VA)

Overall Temperature:

Prediction: Slightly below average, but overall warmer than last year.

Actual:Average High temp 

    Winter 2014/2015: 41.2 F

    Normal Average: 46.4 F

    Winter 2013/2014: 42.4 F

As you can see, it was slightly below average, but this winter was in fact colder on average than last year's winter if you can believe it! This was mostly due to the very mild start to winter last year and the relatively mild end to winter.

Snowstorms Amount:

Prediction: 3-5 snowstorms with no "big one" with a strong possibility of an ice storm

Actual: 4 snowstorms and none of them over a foot. There were some storms with mixed precipitation including one in which sleet and freezing rain was the main form of precipitation.

Pretty much spot on on this one. Storm tracks were just not conducive for the big blizzard that we sometimes receive in this region. Most of the heavier snowfall amounts were well into the Northeast.

Snowfall total:

Prediction: 18-24 inches with higher amounts to our North and West

Actual: Approximately 30 inches with higher amounts to the West and North.

So a little off on that prediction, but that was due to some late developing snowstorms that really put a jolt in our overall seasonal snowfall total.

This winter was definitely exciting for us at ForecastGMU, the constant stream of winter weather provided ample opportunity for us to test our forecast skill and we gained a steady stream of followers as well. We hope to keep you up to date this Spring and will continue to get new articles out.

Thank you all so much for the support!

Greek Week Forecast

Spring is in the air, which means it's time for GMU's annual Greek Week. Will the weather be a repeat of last year? Cold? Rainy? Snowy? Sunny?  I'll let you know!

Please note updates are in RED.

Here is an overview of the week ahead….

And here are hour by hour forecasts for outdoor activities…

SUNDAY

Shack Building: 11am-4pm; Greek Week Kick-off: 2pm-6pm; Shack Sitting: 4pm-9pm

11:00 – 39 degrees; Wind: NW 10mph

12:00 – 42 degrees; Wind: NW 10mph

1:00   – 44 degrees; Wind: NW 9mph

2:00   – 46 degrees; Wind: NW 9 mph

3:00   – 47 degrees; Wind: NW 8 mph

4:00   – 48 degrees; Wind: NW 8 mph

5:00   – 49 degrees; Wind: NW 7 mph

6:00   – 48 degrees; Wind: N 7 mph

7:00   – 47 degrees; Wind: N 6 mph

8:00   – 46 degrees; Wind: N 6 mph

9:00   – 41 degrees; Wind: N 6 mph

Monday

Shack Sitting: 9am-9pm

9:00   – 26 degrees; Wind: N 7 mph

10:00  – 28 degrees; Wind: N 7 mph

11:00 – 31 degrees; Wind: N 7 mph

12:00 – 35 degrees; Wind: N 6 mph

1:00   – 37 degrees; Wind: N 6 mph

2:00   – 40 degrees; Wind: N 5 mph

3:00   – 42 degrees; Wind: N 5 mph

4:00   – 43 degrees; Wind: N 5 mph

5:00   – 44 degrees; Wind: NE 3 mph

6:00   – 44 degrees; Wind: NE 3 mph

7:00   – 43 degrees; Wind: NE 3 mph

8:00   – 42 degrees; Wind: E 3 mph

9:00   – 39 degrees; Wind: E 3 mph

Tuesday

Shack Sitting: 9am-4pm; Shack Breakdown 4pm-6pm

9:00   – 30 degrees; Wind: E 6 mph

10:00  – 31 degrees; Wind: E 5 mph

11:00 – 34 degrees; Wind: E 5 mph

12:00 – 36 degrees; Wind: E 5 mph

1:00   – 44 degrees; Wind: E 5 mph

2:00   – 46 degrees; Wind: E 3 mph

3:00   – 48 degrees; Wind: SE 3 mph

4:00   – 49 degrees; Wind: SE 3 mph

5:00   – 45 degrees; Wind: SE 5 mph
6:00   – 45 degrees; Wind: SE 5 mph

Thursday

Amazing Race

2:00   – 44 degrees; Wind: SW 14 mph

3:00   – 46 degrees; Wind: SW 13 mph

4:00   – 48 degrees; Wind: SW 11 mph

Saturday

Field Day

12:00 – 39 degrees; Wind: N 7 mph

1:00   – 41 degrees; Wind: N 7 mph

2:00   – 43 degrees; Wind: N 7 mph

3:00   – 44 degrees; Wind: N 7 mph

4:00   – 45 degrees; Wind: N 6 mph

  

UPDATE!! It looks like the weather has taken a large turn from what was previously forecasted. For the rest of the week, expect wet and cold conditions. Prepare for periods of wintry mixes throughout the week. Temperatures throughout the week will feel chilly at times, so dress in layers! Good Luck to all teams!

-Katie Thomas

Winter Storm Thor: Updated Timeline

George Mason University is closed for Thursday, March 5th. Winter Storm Warning is in effect until March 5, 09:00 PM. Currently, the National Weather Service has issued Winter Storm Warnings for the counties colored in pink. 

Courtesy of NWS

 Over the past couple of days, weather models have been in dispute over the timing and accumulation totals of Winter Storm Thor. This is the timeline we have as of 10 am Thursday, March 5th. 

Courtesy of Weatherbell.com

As you have probably already noticed, rain has started falling around the region. The heavier rain bands will occur around 10 pm. Temperatures are still relatively warm in the lower 40's.

Courtesy of Weatherbell.com

In the early overnight hours, the rain will begin to switch over to frozen precipitation. We will start to see a mixture of sleet and frozen precipitation enter the vicinity  around 4 am. Surface temperatures hover right above the freezing mark. By 6 am a sleet and snow mixture will make its way into our region. It is expected that we could see up to 1/2 of an inch of frozen precipitation by 7am. 

Courtesy of Weatherbell.com

The next major precipitation switch over will occur around 8 am Thursday morning. Starting around 10 am, we will see the sleet mixture switch over to all snow along with surface temperatures dropping below 32 degrees Fahrenheit. Within this period, it is forecasted that we could potentially receive 1-2 inches of snow by 10 am.

Courtesy of Weatherbell.com

By 1pm all falling precipitation will  now be in the form of snow. Temperatures will have drop to the mid-high 20's. Take a look at the graphic to the left. As you can see there will be some stronger snow bands that will dump higher snowfall totals over those areas. Depending on the location of these bands, at this time there could be between 3-5 inches of snow on the ground.

Courtesy of Weatherbell.com

Although Winter Storm Thor begins to move off to the east, snow bands continue to engulf the northern and central regions of Virginia. During this time, Thor will have dropped between a total of 5-7 inches of snow around our region. The surface temperatures will be in the lower 20's.

Courtesy of Weatherbell.com

By 7 pm precipitation will flip over to all rain, however temperatures remain in the lower 20's. Snowfall totals at this time will be around 6-7 inches.








I hope this helps when deciding when to travel, or perhaps leaving for spring break. Stay safe and use good judgement when traveling during inclement weather! Stay with ForecastGMU for Winter Storm Thor updates!
-Katie Thomas

Winter Storm Thor

Winter Storm Warning in effect for our area from Wednesday 12am until Thursday 9pm. 

The name is ironic enough. This storm is going to be "hammering" us with massive amounts of snow on the back end of a rainstorm Wednesday evening into Thursday evening. Snow from Winter Storm Thor has already blanketed regions of the West, Southwest, and South Central including California, Arizona, and Texas.

Models as of this morning are now learning towards the likelihood of a major snow event for the entire metro area. The GFS model for snowfall within the next 72 hours has totals of 8-10 inches. While other models have totals closer to 3-5 inches. Model output such as this is alarming, but forecasters (especially via media) need to remain skeptical in light of the situation and not be swayed easily either way.

48 hour Snowfall forecast (Intellicast)

The problem with forecasting a major snowstorm far in advance is that the some of the development features for the storm are not present within the initial conditions, meaning that some of the forecast has to be left to probability in the longer range. With all that being said, this system might prove to become the largest snowfall of the season.

This system is quite a complex frontal system with warm air pushing out ahead of the front and cold air moving in later on. The warm moist air moving in tonight into tomorrow is not as warm as once projected earlier in the week. Highs tomorrow will stay in the 40s throughout the day. A strong system of moisture will move into the region from the South Central region bringing warm saturated Gulf and Pacific air with it. By midday Wednesday, rain will begin to fall in moderate amounts. Behind it a large swath of cold air pushes southeast from the Midwest behind a very large cold front. This cold front will plummet temperatures late Wednesday and they will continue to fall into Friday morning. The active and strong jet will intercept this cold air and steer this system directly towards the Mid-Atlantic along with the sufficient moisture.

Then comes the fun part. Later Wednesday, temperatures will start to approach the freezing mark. A change over to snow requires the entire column of air to cool below freezing. If any sufficient part of the air from upper cloud levels to ground is above freezing enough to melt the ice crystals than the changeover might not happen immediately. If it does though, accumulation may start to pile up Wednesday night into Thursday morning shifting snowfall totals higher than some are projecting. Sleet may mix in within the first couple hours of the changeover.

Currently the highest totals of the storm are projected to be in the Northern and Western portions of West Virginia, Maryland and Virginia and lower totals projected to be seen in Southern and Eastern suburbs of DC.

With many different snowfall forecasts out there, I will just use NOAA's Probabilistic Snowfall forecast as my reference to likelihood of different 24 hour snowfall totals.

Starting at 18Z Wednesday (1 pm Wednesday until 1 pm Thursday):

Probability of at least 1 inch of snowfall

Probability of at least 2 inches of snowfall

Probability of at least 4 inches of snow

Probability of at least 6 inches of snow

Probability of at least 8 inches of snow

So what the maps are telling us, is that there is a good amount of confidence that there will be at least 4 inches of snow, but less confidence of totals in the higher end of the range.

Timeline for Winter Storm Thor:

Wednesday Morning: Rain will begin to pick up around 6-7:00 am and will continue throughout the morning. Temperatures at this time will hold in the low to mid 40's and will stay that way until the afternoon. It will be a steady rain at this point. No showers or downpours.

Wednesday Midday/Afternoon: Rain will continue at this point. It may die down a bit midday, but will pick back up in the afternoon. Temperatures will reach a high of 48 around 2 pm, then begin to slowly fall through the later afternoon hours. Rain intensity will pick up after 5 pm.

Wednesday Evening: Rain showers will and wind will increase as the sun goes down as temperature begins to sharply decrease. Temperatures will be in the mid 30's by 8 pm and could be below freezing by 10pm. Look for a changeover to snow to be around this point. The time of the changeover is important due to how much of the precipitable water falls and sticks as snow as opposed to rain. This could shift accumulation totals farther up or way farther down than forecasted.

Wednesday Night: All snow expected by this time. Accumulation may start to pick up after midnight, or like in situations in past storms this winter season, it may continue to accumulate by this point. Expect around 0.5-1 inch of snow on the ground by 2am.

Thursday Early: Snow will start to pick up in intensity by the early morning hours of Thursday and accumulate at rates of at least of 1 inch an hour or higher. By sunrise there could be anywhere from 2-4 inches of new snow on the ground including on the streets. Temperatures will stay consistent in the upper 20s with wind gusting out of the NNW at 20-25mph. Visibility at this time will be very low. 

Thursday Morning/Midday: Snow will continue through the morning hours at relatively high accumulation rates, though these rates may diminish after 11 am. Total snowfall by 11am should be around 3-4 inches. Temperatures will continue to fall through the day. Temperature will be below 25 by 12 pm.

Thursday Afternoon: Snow will finally start to dissipate and turn to more snow showers/flurries by early afternoon before completely ending by 6 pm. Temperatures will continue to drop as wind continues to gust out of the NNW at 20-25 mph. Additional accumulation by this time around 1-2 inches.

Thursday Evening: Skies will begin to clear by sundown on Thursday. Temperatures will drop into the upper teens and eventually mid-single digits overnight. Wind chill values will be well below 0. Record lows possible in western suburbs.

Snowfall Forecast: 4-8 inches with high variability. Tomorrow's update will help narrow that down a bit.

Impact: Medium-Medium High-with plenty of time to prepare, road crews are going to be out in full force making sure that this storm has a minimum amount of impact on the roads. That being said, look for road conditions to drastically deteriorate by early Thursday.

Notes on Delays/Cancellation: It is way too early to state any conclusion on whether there will be a delay or cancellation Thursday. Though if I were to have put odds on it right now? I will put it at 50-60 percent chance of at least a delay and 30-40 percent chance of a full cancelation.

Another update is coming tomorrow, so stay tuned. A more detailed picture will become clearer after tomorrow morning's model runs. Thank you all for checking in!

-Jamees