591 FXUS64 KAMA 102347 AFDAMA Area Forecast Discussion National Weather Service Amarillo TX 547 PM CST Mon Feb 10 2020 .AVIATION... 00z TAF Issuance...IFR conditions for AMA through the early morning hours before becoming MVFR through the remainder of the period. DHT and GUY will see the potential for MVFR conditions as early as 06z to 09z and continuing through the period. The precipitation from today has now pushed east of all three TAF sites. Snow will begin to push into the north and west with DHT/GUY both including a TEMPO for light snow as early as 06z to 09z. AMA will see the onset of snow a few hours later around 12z. After 18z, the snow potential decreases with a lull in the precipitation through the TAF period. There is another potential to see a secondary band of precipitation after 00z tomorrow. Winds will remain below 15 knots through the period with gusts up to 20-25 knots possible in the early morning hours. Rutt && .PREV DISCUSSION... /Issued 239 PM CST Mon Feb 10 2020/ SHORT TERM...Tonight through Tuesday night... Active weather expected through the short term periods. Current satellite shows and upper low off the coast of southern California, broad southwesterly flow from the Bay of California into the Missouri Valley, with a lead disturbance in this flow over West Texas leading to light precipitation across the southeastern half of the TX Panhandle. At the surface, cold front that pushed south yesterday is located between Interstate 10 and the Rio Grande with a second cold front to our north draped across NE, pushing south. First order of business is the ongoing mixed precipitation ahead of the aforementioned lead disturbance. With our morning RAOB showing a warm nose of about 4C, current surface temperatures hovering around freezing and surface dew points in the 20s, getting some reports of light freezing rain/drizzle and sleet across the southeastern TX Panhandle. Expect this cold rain/FZRA/sleet mix to continue for the remainder of the afternoon and early evening with light snow to become dominant as the second cold front mentioned above approaches, so will keep the Winter Weather Advisory going. Attention then turns to the snow event early Tuesday morning through Tuesday night. Upper low expected to move eastward over the Gadsden Purchase with guidance in general agreement an additional lead shortwave will eject northeastward and reach the Panhandles around 12z Tuesday. Broad ascent due to the approaching upper low combined with additional PVA ahead of the shortwave should lead to at least light snowfall across much of the CWA. Additionally, stronger ascent is expected to focus on a 700mb frontogenetic zone draped roughly along a TCC-PYX axis. It should be noted that guidance has backed off a bit on instability above this zone, with EPV* values closer to zero compared to previous runs. Main limiting factor for snow, besides a bit less instability than previously thought, will be dry air in the 600-500mb layer, which includes the dendritic growth zone for this event. Still think snow production will occur given strong ascent, but have reduced forecast snow amounts a bit in deference to the trend toward larger dewpoint depressions in the DGZ. Despite the lower overall totals, timing of this event will coincide with the morning commute, so broad impacts are still likely. Potential second round of snow Tuesday may arrive Tuesday night, as EC/NAM depict another disturbance arriving just ahead of the main wave. With several ensemble members and operational runs not depicting this yet, have simply elected to increase PoPs a bit during this time period. With forecast snow amounts now broadly below 6 inches and the main snow event now around 12 hours from onset, will replace the Winter Storm Watch with a Winter Weather Advisory. Ferguson LONG TERM...Wednesday through Monday... Shortwave trof exits east of Texas and Oklahoma Panhandles during the day on Wednesday, with support for light precipitation in southeast sections. Low pops for morning light snow and afternoon light rain are retained for southeast sections on Wednesday. Dry mainly northwest flow aloft expected through Thursday following trof's departure. Flow aloft becomes southwest on Friday as next shortwave trof moves through northwestern CONUS. This trof or its remnants should pass forecast area Saturday night or Sunday morning, bringing a slight chance of light rain to southeast sections. At the surface, north winds resume on Wednesday as weak cold front associated with shortwave trof moves through. Modest warmup expected with highs on Wednesday generally in the lower- to mid- 40s. Continued cool on Thursday as reinforcing surge of cold air moves in from the northeast. Warmer on Friday with highs near normal as southwest winds resume. Saturday and Sunday expected to be warmest days of the forecast with highs in the 50s and lower-60s. Warmup ends on Monday with next cold front. Cockrell && .AMA Watches/Warnings/Advisories... TX...Winter Weather Advisory until 6 AM CST Wednesday for the following zones: Armstrong...Carson...Collingsworth...Deaf Smith...Donley...Gray...Hemphill...Hutchinson...Lipscomb... Ochiltree...Palo Duro Canyon...Potter...Randall...Roberts... Wheeler. Winter Weather Advisory from 9 PM this evening to 6 AM CST Wednesday for the following zones: Dallam...Hansford... Hartley...Moore...Oldham...Sherman. OK...Winter Weather Advisory from 9 PM this evening to 6 AM CST Wednesday for the following zones: Cimarron...Texas. && $$ 23/11