078 FXUS63 KOAX 121120 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 520 AM CST Wed Feb 12 2020 ...Updated FOR 12Z Aviation Forecast Discussion... .DISCUSSION... Issued at 340 AM CST Wed Feb 12 2020 The main forecast concerns are rain/snow chances today, snow amounts today into this evening and wind chills tonight into Thursday morning. So plenty to deal with in the short term. Water vapor satellite loop early this morning showed a closed low over far northern Chihuahua Mexico. Mid and high level clouds were streaming northward from the southern Plains ahead of this feature. Meanwhile a trough in the northern stream of the mid tropospheric split flow pattern was digging southeast from MT. Surface analysis at 3 am showed a cold front stretching from northern MN to near the ND/SD border then back into eastern MT. As expected, locally in eastern NE and southwest IA, temperatures have been fairly mild overnight with south/southwest winds. Ahead of the front today, temperatures should top out in the lower and possibly mid 40s. Cold air will move into the far northern parts of northeast NE by 9 am or so and so highs there will only reach the 30s. A very sharp change in temperatures and a blast of strong winds will move through the Omaha, Council Bluffs and Lincoln metro areas between 3 pm and 6 pm. It roads are wet, there could be a flash freeze, with roads icing over rapidly. We will not issue an advisory for this area for now, but it is possible that one may be needed later today based on timing of precipitation. Showery precipitation is likely based on forecast soundings showing fairly steep lapse rates from 85o mb to 700 mb. There will also be some frontogenesis to help add to the modest large scale forcing. Will keep the previously issued Winter Weather Advisory for our northern tier of counties from 10 am to 6 pm today. Combination of some light snow, possibly up to around an inch, strong winds causing blowing snow and sharply colder temperatures are the main reason for the advisory in the north. Snow amounts elsewhere in the area should range from a trace up to half an inch or so, with a small chance of snow amounts near an inch outside of the advisory area. Winds will increase to 25 to 30 mph with gusts possibly over 40 mph. Tonight, issued a Wind Chill Advisory, starting with the first segment near the SD border at 6 pm and then adding counties with time from north to south through the evening. It does not look like we will get to -20 F wind chill at the KS border, but since KS has a lower Wind Chill criterion, we will match up. Wind Chill Advisories in eastern NE and southwest IA are generally issued for values of -20 to -29. Snow showers should end in northeast NE by 5 or 6 pm and then end by 10 or 11 pm in far southeast NE and the southwest corner of IA. Clouds will also decrease from northwest to southeast through the evening as cold high pressure builds in. Look for lows tonight to reach -3 to -10 in the northern half of the forecast area and about 3 above to -2 south. Winds will also slowly decrease a little later tonight into Thursday morning. Highs on Thursday in eastern NE should mostly reach 9 to 19 and 7 to 13 in western IA. Lows Thursday night will probably be during the evening hours, with milder air trying to move in with south winds later Thursday night into Friday. Brisk south winds of 15 to 30 mph are likely Friday, which should help push highs into the 30s. The wind will still make it feel pretty cold though. Dry weather is expected on the weekend, at least for now, with highs in the 40s to lower 50s. Sunday night into Wednesday. There is a fairly high amount of model variance in regards to precipitation potential and even the surface pattern for Sunday night into Monday. The operational 00Z GFS is mainly dry, but the ECMWF shows decent potential for light to moderate precipitation. For now will keep some POPs in the 20 to 40 percent range. By Tuesday afternoon and into Wednesday, the dry pattern should return. Temperatures Monday should still be fairly mild, Tuesday looks colder (highs mostly in the 30s), and then temperatures should moderate a bit for Wednesday. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) Issued at 520 AM CST Wed Feb 12 2020 A strong cold front will push through the area today. VFR conditions this morning will deteriorate this afternoon. Rain showers or a mix of rain and snow will be possible ahead of the front with snow showers behind the front. MVFR conditions and possibly brief IFR conditions could occur in the snow showers. Winds will become north or northwest 20 to 25 knots behind the front with gusts 32 to 37 knots. Conditions will trend back to VFR at KOFK by 23Z and then to VFR for KOMA and KLNK by 02Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Wind Chill Advisory from 8 PM this evening to 11 AM CST Thursday for NEZ030>034-042>045. Wind Chill Advisory from midnight tonight to 9 AM CST Thursday for NEZ078-088>093. Wind Chill Advisory from 10 PM this evening to 9 AM CST Thursday for NEZ050>053-065>068. Winter Weather Advisory from 10 AM this morning to 6 PM CST this evening for NEZ011-012-015>018. Wind Chill Advisory from 6 PM this evening to 11 AM CST Thursday for NEZ011-012-015>018. IA...Wind Chill Advisory from 8 PM this evening to 11 AM CST Thursday for IAZ043-055-056. Wind Chill Advisory from 10 PM this evening to 9 AM CST Thursday for IAZ069-079-080-090-091. Winter Weather Advisory from 10 AM this morning to 6 PM CST this evening for IAZ043. && $$ DISCUSSION...Miller AVIATION...Miller