875 FXUS64 KOUN 090507 AFDOUN Area Forecast Discussion National Weather Service Norman OK 1107 PM CST Fri Mar 8 2019 .DISCUSSION... 06Z TAFs. && .AVIATION... Locally dense fog has developed across portions of northern Oklahoma, especially in areas around KAVK. This fog has been between TAF sites and the best signal is that it will continue to be localized up there and likely not to affect the TAF sites. There is some IFR ceilings in the north too that will affect areas around KPNC, but this will become less widespread with time. Low- level wind shear will still be an issue through 15Z with 50 knots or so above the inversion. Showers and thunderstorms are still expected to develop overnight, but will push the timing of this a couple of hours later than the previous TAFs. Surface winds will shift to southwesterly then northwesterly between sunrise and noon with gusty winds expected most of the day. && .PREV DISCUSSION... /issued 814 PM CST Fri Mar 8 2019/ UPDATE... Made some minor changes to PoPs and weather grids based on latest trends. Added mention of patchy fog across portions of northern Oklahoma through about 9z where observations have shown lowering visibilities. Also lowered PoPs before 6z tonight as hi- res models have backed off precipitation signal this evening and upstream obs show radar echoes aloft are fighting a decent amount of mid- level dry air that was observed on the 00z OUN sounding. Still expecting storms will quickly develop after 6z tonight across west Texas and the Texas panhandle as strong shortwave trough and attendant forcing moves over the region. These storms should then move quickly northeastward into our area with hi-res models showing an intensification trend during the 9-12z timeframe as they approach roughly the I-35 corridor where higher moisture/instability will be present. Main threat still looks to be large hail up to golf balls and high winds with the stronger storms. Additionally, although the overall threat remains fairly low, an isolated tornado or two cannot be ruled out across south- central and southeast Oklahoma after about 9z as a brief overlap of favorable low-level shear and instability looks to occur. Most activity looks to clear the area by about 15z tomorrow morning. Ware PREV DISCUSSION... /issued 551 PM CST Fri Mar 8 2019/ DISCUSSION... 00Z TAFS. AVIATION... Some MVFR ceilings (and even patchy IFR ceilings) persist in the central and north central part of the state. KOKC and KOUN seem to be right at the edge of this stratus deck with an improving trend expected over the next couple of hours, but it will likely linger longer in the north including KPNC. Otherwise, widespread mid/high clouds expected over the area overnight. Low-level wind shear will be widespread across the area with southwest winds of around 50 knots within 2000 feet of the surface. Showers and thunderstorms will be widespread across much of the area after 06Z, but will clear most of the TAF sites by 10Z-12Z. Showers/storms are still possible at the western sites (KCSM, KWWR), but the probability is not quite high enough to include a TEMPO group there. Surface winds will shift to southwest then northwest Saturday morning and be quite gusty much of the day. PREV DISCUSSION... /issued 404 PM CST Fri Mar 8 2019/ DISCUSSION... An active weather pattern ahead of us for tonight and the first half of next week. An upper wave currently across the southwestern U.S. will be moving in tonight, destabilizing the atmosphere, and pushing a cold front through late Saturday morning. Showers and thunderstorms are likely to develop late tonight, with the highest probabilities generally along and east of I-44. The strongest instability will be in place east of I-44, with MUCAPE values of 2000-2500 j/kg capable of producing some severe thunderstorms after midnight, with hail up to golfball size possible in the risk area. DCAPE values suggest severe wind gusts of 60 to 70s mph are possible in some of the storm downdrafts, while the wind sheared environment cannot rule out a tornado developing across southeast Oklahoma. The storms should be exiting our area late Saturday morning as the surface boundary pushes through. However, the slightly cooler air will lag to the north, and start to surge in as Saturday night with temperatures cooling back down to freezing across northern Oklahoma, and to the mid 30s to 40 degrees across the rest of our area. For Sunday, expect cooler than normal daytime temperatures, with light rain increasing from the south on Sunday night. Our next weather system will move in early next week, as the upper flow becomes meridional with another wave coming through. Rain chances begin on Monday and increase on Tuesday into Tuesday night with isolated storms possible. The latest model PW values are consistent with next weeks system being a big rainfall producer, and could result in some localized flash flooding hazards. By the end of next week, our area will be tapping from Pacific based to more Canadian air, with more winter-like temperatures making a return. Fire weather conditions will be elevated across far western edges of Oklahoma and north Texas on Saturday afternoon, as the westerly shifting winds will be blowing in dry air off the Texas Panhandle. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 50 64 35 47 / 70 20 0 10 Hobart OK 46 66 33 48 / 60 0 0 10 Wichita Falls TX 53 69 40 51 / 60 10 0 30 Gage OK 42 62 26 49 / 40 0 0 0 Ponca City OK 48 60 30 49 / 70 20 0 0 Durant OK 58 67 41 52 / 90 50 0 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ 99/99/99