Area Forecast Discussion/OK/Greg Whitworth/Fox 25

** Potential for Slick roads north of I-40 from the western state line to north sides of OKC and northeast up the Turner Turnpike into Tulsa, then north of highway 412 east of Tulsa
**** Dense fog this morning, some ice where temperatures are below freezing
**** Temperatures may continue to rise tonight after dark
**** Second round of cold air, possible more winter mix coming
**An upper level storm over the southwestern US will eject eastward today, passing over Oklahoma, especially the northern counties. Meanwhile, southeast to south winds will pull moisture into the cold airmass over Oklahoma, gradually warming temperatures.Rain is expected to develop across the state as the upper level storm approaches. South winds should drive temperatures above freezing in most areas by 10 a.m. A weak frontal boundary stretches along and slightly north of I-40 this morning and has provided some transition between airmasses but is slowly eroding away.A warm front near the Red River (as I forecast last Sunday) will gradually make it's way into southwest OK. It is expected to pass through Altus but may not make it through Lawton. South of the front, highs should be near 60, while north of the front, across the majority of the state, temperatures will slowly climb into the 40s by afternoon. BUFKIT data from NAM handled this with reason with some minor model errors.Due to the nature of the saturated airmass with fog in the morning, temperatures will have a tough time warming. Increasing south wind speeds should cause temperatures to continue climbing after dark tonight. Today's high will likely be Tuesday's morning low.A weak front will drive in from the west overnight going into Friday, turning winds westerly. It may then be followed by a front out of the north, gradually turning winds northeast across the northern half of the state. Forecasters are all over the place with this one. I kept the 52 previously forecast. Skies look mostly sunny which should be a refreshing change to have a day with light winds and sun. However, I am concerned the day could turn out to be colder than 52. National snow analysis fromhttp://www.nohrsc.noaa.gov/nsa/shows snowpack to our northeast. A northeasterly wind over the snowpack could be colder than a northwesterly wind where there's no snowpack. Unfortunately I didn't think to look at this before laying down the numbers.Another arctic front is forecast by most models to arrive around 21Z (3 pm) Saturday. History, and the previous arctic front, has proved that these often come in earlier than forecast. The last front came in about 5 hours early. As a result of this being an arctic airmass, I am pushing the time frame for frontal arrival up to 10 am (16z) and dropping the high temp on Saturday to 48 which might be generous.GFS/DGEX both wanted to clear the skies on Sunday after the frontal passage. History has also show that after some moisture return, an arctic airmass will hold clouds in place. I have discounted GFS/DGEX and kept it cloudy from Saturday straight through Monday. There looks to be several weak waves coming in from the west to spread clouds over us.ECMWF shows this next arctic airmass doesn't have quite the density or 850 mb cold values the last one was screaming at us. Therefore, I'm a bit puzzled why GFS and other forecasters have the nubmers so cold on Monday morning. I went ahead and kept it, and with light winds and clouds we should not get out of the teens if that morning low is correct.South winds kick in Monday night so we have a second case where the high temperature for Monday may be after dark and be the same as the Tuesday morning low.Model runs since Sunday have shown a system coming in the 23rd. I was about to write this in the last discussion but decided it was too far out and uncertain to mention at the time. I have introduced high pops at 40% Tuesday to account for consistency with the timing and strength of the incoming shortwave and cold front. Precipitation type looks to be a mix at this time but of course there's plenty of uncetainty and the GFS is not handling it well at all.With northwest winds on the 24th I do not think it will get out of the 20s given that the front and associated high look similar to the one coming in on Saturday. This could set us up for a cold Christmas but at this time I do not see any precipitation. Our only hope for snow will be the 23rd.
If you have any good photos of freezing fog, weather related accidents, ice, etc, feel free to send them to weather@okcfox.com I'm trying to set up where these discussions will come from weather@okcfox.com ..If I can get the server to save the email list.
OKC 30/47 47/52 39/48 16/23 10/18 18/33 15/28Pops 70% Thurs, 20% Sat, 40% Tues, 20% Wed.