Greg Whitworth/Forecaster/Fire Watch to Winter Storm Watch

For those who are not familiar with Greg Whitworth, he is our local Fox 25 TV forecaster. He is also a storm spotter with Emergency Management. Greg does a fantastic job of keeping us updated via our county radios during tornadoes/other weather events when we are activated by EOC. Following is his latest forecast.

A burn ban has been issued statewide. High fire danger continues today with winds gusting to 40 mph in western Oklahoma. Temperatures fall back below freezing tonight across all but southern Oklahoma. High resolution WRF shows some showers developing over the southeast TX panhandle and moving through western OK overnight before temps fall below freezing. Snow then develops as this precip area moves into colder air near Enid or Ponca City. The majority of the snow should stay back out into the Texas and OK panhandle overnight but make it's way into the state quickly by sunrise. Snow should spread across the northern 1/2 to 2/3rds of the state shortly after daybreak, reaching OKC around 8 a.m. I have knocked tomorrow's temperatures down significantly below MOS because it will be snowing when heating should be occurring. Therefore we will not realize the mid to upper 30s shown by the MOS. This is a typical bias.

Latest look at the WLNS local WRF shows 1.3" of snow in OKC. Accuweather LocalCast has 2" across the northern half of the state with an anomaly of 3" in OKC. What I'm really relying on is the 6Z NAM. It has performed vastly superior to all other models for the last several events. Here's it's forecast.

http://wxcaster4.com/nam/CONUS1_MESO-ETA212_SFC_ACCUMSNOWFALL-KUCHERA_84HR.gif

This would place OKC in a 1-2" situation with 3"+ starting in northern Kingfisher County and 4-5" around Ponca City with higher amounts in SW Kansas. I will update the web Feature graphic with this by 11 a.m.

There will be a tremendous amount of blowing and drifting snow. Given forecast totals, I expect many roads across north-central Oklahoma to be drifted shut and travel along I-35 north of Stillwater past noon may be nearly impossible.

Skies should clear out Friday morning with calm winds, so will go below MOS guidance on temperatures. I did the usual combo of taking the GFS dew point and the warmest MOS and dividing by two which gives us a low of 18. I am now realizing this is likely too warm because the snow tends to cause temps to drop significantly.

Will cut MOS significantly for Friday as snow pack on the ground will cause cold highs. I have already cut Friday by 5 degrees and next shift will likely need to drop it more. Winds will be screaming out of the south and it will be sunny, eating the snow so areas south of OKC that receive little snow will likely realize highs in the 50s.

Saturday looks to cloud up as a weak shortwave passes during the afternoon. GFS shows a front passing around 9 a.m. with winds turning to the north. I kept the same forecast as the previous shift for the most part with much uncertainty in the extended. I have not been watching this time period run to run so I'm a little too unfamiliar with it to make many adjustments.

Winds go light Sunday morning. Models bring some sort of dryline in around Sunday noon with winds staying southwesterly possibly through Monday. This explains why IPS Meteostar shot temperatures upward into the 60s for Sunday and 70s for Monday. This could verify if IPS site is correct. DGEX does not agree with it but DGEX has not been doing well lately. Again I do not have enough confidence to change the previous forecast but next shift should examine the possibility of southwest winds. If the winds indeed go southwest, it is unlikely pops will be needed for Monday. I actually raised pops on Monday before seeing this given the strong shortwave seen on the GFS. It almost appears a surface low parks itself over the state Saturday-Monday. A small variation 75 miles either side could make the difference between rain or no rain. Given the southwest wind bias of the GFS, I think raising pops may have been a good idea.

A significant cold front arrives Tuesday morning. 540 line goes way down south into Texas as 1028 high builds in during the day. I have dropped temps 6 degrees below previous forecast (and MOS) as a result of this. There could be a brief area of snow so I have included 20% pops.

Temperatures rebound quite nicely next Wednesday with highs near 50 again, if not warmer, with plenty of sun.

Another cold front arrives Thursday at 9 a.m. so went below IPS meteostar on temps.


Forecast graphics:
http://www.okcfox.com/newsroom/wx/images/WEB_KOKH_STATE_FORECAST_1.JPG
http://www.okcfox.com/newsroom/wx/images/WEB_KOKH_STATE_FORECAST_2.JPG
http://www.okcfox.com/newsroom/wx/images/WEB_KOKH_7day.JPG


New NAM snow forecast:

http://www.okcfox.com/newsroom/wx/images/WEB_FEATURE.JPG