Wednesday, January 17, 2007
Winter Storm Update
Plenty of uncertainty still exists with our upcoming winter storm. I'm sure that's not a shocker to you. The NAM's timing at this point seems to be more for Saturday night into Sunday afternoon. The GFS supports a faster solution that moves the winter weather in by Saturday afternoon and ending by Sunday morning. Our upper level storm is currently over southern California, and this will create the lift for the forecasted winter weather.
Looking at the 0Z NAM data, temperatures look cold enough Saturday night for snow to fall; however, warm air advection around 5,000 feet looks to take place toward Sunday morning. This warming may change the snow to more of a rain/sleet mix for Sunday morning.
The GFS supports a colder solution. The 850 mb -5C isotherm cuts north of I-40, which would create the possibility for heavy snow to fall Saturday night across northwest Arkansas. The GFS also paints snow for the River Valley.
There is still too much of a difference between models to confidently say what will happen. I'm feel good to say that everybody will see some sort of winter precipitation, but we're not ready to forecast snowfall totals.
Here's a couple of interesting winter weather rules of thumb:
1. It takes about 1200ft of warm air to melt snow.
2. Sleet is the result of a warm layer greater than 1200ft melting the frozen precipitation as it falls. The precip them falls through a freezing layer at least 4,000 feet thick.
Looking at the 0Z NAM data, temperatures look cold enough Saturday night for snow to fall; however, warm air advection around 5,000 feet looks to take place toward Sunday morning. This warming may change the snow to more of a rain/sleet mix for Sunday morning.
The GFS supports a colder solution. The 850 mb -5C isotherm cuts north of I-40, which would create the possibility for heavy snow to fall Saturday night across northwest Arkansas. The GFS also paints snow for the River Valley.
There is still too much of a difference between models to confidently say what will happen. I'm feel good to say that everybody will see some sort of winter precipitation, but we're not ready to forecast snowfall totals.
Here's a couple of interesting winter weather rules of thumb:
1. It takes about 1200ft of warm air to melt snow.
2. Sleet is the result of a warm layer greater than 1200ft melting the frozen precipitation as it falls. The precip them falls through a freezing layer at least 4,000 feet thick.
Posted by Drew Michaels at 8:05 PM
15 Comments:
Just let it snow in the rivervalley!!Thats what I pray anyway..
Thanks for the update Drew. Pretty close to what I was thinking. Yes the NAM does make us have issues for sure.
Snow Angels. Yaay!
I think the reason the models are having trouble handling the next storm system is because it is still offshore the southern California coast. Once all the energy is inland later today, the models will be able to take a much better sample of observations and I believe they will come into better agreement. New WX discussion out shortly....
Justin Povick
Sunrise Meteorologist
n.w.s. tulsa still has the rivervalley getting snow and sleet!!
other stations and national weather service are saying 5 to 7 inches for nwa should i believe them?
lets hope you can..
other stations and national weather service are saying 5 to 7 inches do u support that prediction?
we need an update..
Again this storm system is still offshore the California coast, so the models are not recieving a good sampling of the upper air obs. I wouldn't be surprised to see some VERY LARGE CHANGES in the models the next 12-24 hours. Therefore the chance remain for snow as far south as Fort Smith, though it it TOO early to make a call for several inches of snow.
I already put out my morning weather blog update and it sould be viewable soon.
Justin Povick
Sunrise Meteorologist
If the models differ so much...how can you go to air with 5 to 7 inches of snow..that takes balls! Can you imagine if this turns out to be sleet/rain...NWS will look like complete fools.
Will we have school on Monday?
I dont know its realy falling out there and also we have a 100% chance of more tommaro in NWA, so I dont know. In fact I dont think anyone knowes untill it happends
I've heard cold rain, mix, dusting to 1'', 1-3'', 2-4'', and even 5-7''. So who knows what could happen.
its white!!!!!!!
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