Wintry Wednesday Ends... Big Storm on the Horizion?

Good evening everyone and welcome back to the old weather blog. London was spared the worst of this winter storm, and to be honest I'd rather us seen all the rain we did than the ice central KY saw. Up next your 5 day Forecast, Storm Review, and a look into the future *Dusts off the old Magic 8 Ball.*

Your 5 Day Forecast for London KY:

Thursday: Mostly Sunny with a low of 23, and a high of 38.

Friday: A Clipper system crosses to our north, bringing us a chance of some light snow, otherwise we'll be mostly cloudy with a high of 32 and low of 27. Total Accumulation for London Dusting to 1".

Saturday: A few morning snow showers wrap up and leaves us with partly cloudy skies by the end of the day. A low of 19, and high of 34.

Sunday: Sunny with a high near 50 and low of 26.

Monday: Ah here comes the fun day, I'll talk about it more in the forecast discussion, but for now all you need to know is a chance of rain changing to snow, with a high of 34 and a low 27.

Forecast Review: Forecast: 46/27 Actual: 42/28 *Note temp is still falling so low could be a little lower*

Not to bad, 4 degree bust on the high is acceptable when there were reports in Knox county of 61! 20 Degree temperature spread in that many miles... CRAZY! None of the models had 60's in here, even the RUC was only putting 50's into southern KY, kudos to the folks out at KYmesonet for their hard work and getting all these observation sites up.

As far as snowfall totals, busted hard but I'm willing to take the hit. We barely got a dusting of snow in London, not an inch but oh well, snow didn't last as long as I thought and the ground was just too warm to hold the snow after a day of rain. BTW a note about the rain from London yesterday from the NWS in Jackson.

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE JACKSON KY
1242 AM EST WED JAN 28 2009

...RECORD DAILY MAXIMUM RAINFALL SET AT LONDON...

THE DAILY RAINFALL TOTAL AT THE LONDON CORBIN AIRPORT WAS 1.54
INCHES ON TUESDAY JANUARY 27TH. THIS IS THE MOST PRECIPITATION EVER
RECORDED ON THIS DATE. THE PREVIOUS RECORD WAS 1.43 INCHES SET IN
1972.

So all and all, a hard forecast period, I'm glad we're done with it. I at least get a few days of breathing before the next challenge of this winter.

Forecast discussion:

Okay so the forecast for the next couple of days is going to be relatively easy compared to the last 72 hours of mess. A clipper system moves in tomorrow and could put down a dusting of snow, here's the GFS's take on it.

As you can see, it's not a very well organized system, so I'm not expecting much from it. Let's move it on to your weekend.


As you can see high presure is in control for Saturday and again on Sunday, on the back side of that high on Sunday temperatures could get above 50. Nice weekend to get out and enjoy because the mess rears it's ugly head on Monday into Tuesday.

WARNING: LONG TERM FORECAST DISCUSSION, Not an actual forecast, but discussion on the possibilities.

Okay wall of text and maps incoming, so considered yourself warned. This storm coming into the picture on Monday has been catching a lot of peoples attention for the last 72 hours. Since we're within the 5 day period it's time to adress it.

GFS for Friday Afternoon: Big time Low pressure off to our south, Temps below freezing at 850, lot's of QPF *Think of this as if everything fell as liquid precipitation in the 6 hour period for the model.* Now lets look at the precipitation total for the entire event according to the GFS.


Assuming that all fell as snow at a 10:1 frozen to liquid ratio, that would mean around 10 inches of snow for over half of KY! I am not forecasting that, that is just what this model is showing.

Time to look at the other long range models, Canadian, European, and Japanese:

Canadian

European


Japanese:


Okay, so all 4 long range models are showing it on the horizon for Monday night/Tuesday Morning. Also the GFS and Canadian Ensembles are showing similar solutions. So game on for massive snow right? Not so fast, Surface temps according to the 12z GFS and Canadian.

Monday Evening GFS:



Tuesday Morning:




Canadian:
Monday Evening:
Late Monday:
Tuesday Morning:

Okay so both of these models show a rain to snow transition. Now time to look at some upper air data, Looking at 3 levels, 300 MB's (30,000Ft) *Jetstream Level*, 500 MB's (18,000ft), and 850 MB's. (5,000ft)

300 MB Jetstream:

GFS:

Euro:


CMC:

Notice in all 3 model's, I've drawn a cross in the middle of the Jetstreak, the areas of most intense wind in the Jet Streak. In the quadrants I've put the astrics are the areas of the most intense lift, a key ingredient in getting precipitation, so the potential for heavy precipitation is there.


Okay 500 MB: Here we're looking at Vorticity, the amount of spin in the atmosphere. More Vorticity = Strong system in layman's terms.


GFS:





JMA:




CMC:





In all 3 Models here we see there is ample vorticity over eastern KY, lots of energy to work with.

Next 850, just going to show the GFS just to show my point with it.



On both these maps, I've circled areas of cold air advection, areas where cold air will move in and bring the temperatures down. Models have a hard time handling temeprature advection, so it's likely temperature will be colder than the models antcipate in these areas.

Okay so what does all this mean. The ingredients are coming together for a snowstorm this part of the country hasn't seen in about 16 years. Henry from Accuweather is calling this storm 75% of the Blizzard of 93. Folks invoking the Blizzard of 93 around here is liking invoking the name of Jesus Christ to a demon possessed person, it causes much gnashing of teeth, and shouts and outbursts of rage. For him to say that means he thinks it's on.

Chris Bailey is about to pull the trigger on a Winter Storm Threat 5 days out, something he very RARELY does. All the ingredients are there for a huge snowstorm, ample mositure, cold air, and a ton of lift.

What can go wrong between now and then... A lot. The models for the last decade have trended Northwestward with dang near every winter storm. What this means is that the storm would go farther west and north than the models would show in the 3-7 day range. An example of this was the early March storm last year which was showing significant snow up to the last 24 hours, and then shifted it's track west of the What else can go wrong, a storm like this requires a phasing of the Jet Streams, something the models don't pick up on very well. If this doesn't happen, our storm is a completely different storm than the one the models show right now.

So where do we go from here? The potential is there for a MASSIVE winter storm for most of the east coast next week. Do we see Blizzard of 93 or similar conditions, I just don't know at this point. From here we take it one day at a time, keep a vigilant eye on every model run, and if it's still showing what it showed today 24 hours before the event, be ready to ride out one heck of the storm.

My Forecast for Monday, Rain changing to snow at this point. This can change between now and Monday. Sorry for the wall of text weather explanation, but I wanted to break this down from a serious Meteorological prospective.