108 FXUS64 KAMA 202136 AAB AFDAMA Area Forecast Discussion...UPDATED National Weather Service Amarillo TX 436 PM CDT Mon May 20 2019 .UPDATE... Doing quick update to POPs, mainly to lower some in the west. Not removing them completely in west mainly out of respect for very strong lift that remains over the area, but lack of moisture may preclude precip all together AMA to DHT and SW. Given very wrapped up H5 low to the NW and moisture moving around the base, have included some slt chc to chc POPs across the north on Tuesday as well. Last but not least, have issued a high wind watch for the SW four counties where all models agree on wind speeds and gusts approaching warning criteria of sustained 35 kts and gusts to 50 kts. If other models trend toward more agressive GFS, we may need to consider more counties in a warning surrounding the original four, assuming we upgrade the watch tomorrow. && .PREV DISCUSSION... /Issued 1236 PM CDT Mon May 20 2019/ ..UPDATED FOR AVIATION DISCUSSION...SEE BELOW... PREV DISCUSSION... /Issued 1223 PM CDT Mon May 20 2019/ MESOSCALE UPDATE... .Severe weather outbreak likely this afternoon... * Synoptic Overview: The synoptic pattern could hardly be more favorable for a Plains severe weather outbreak with veering wind profiles, tons of instability, yada yada yada (it's all there). * Mesoscale: Morning convection continues early this afternoon northwest of a stationary boundary that basically lays across US 60 from Amarillo to Canadian. This boundary desperately wants to lift north as a warm front in response to the approaching upr system, but continues to be reinforced by outflow from ongoing convection and is basically lodged in place. SE of this bndry, an explosive warm sector is developing with MLCAPE values that may eventually push to near 5000 J/kg in the SE TX Panhandle! Effective shear values will be an eye popping 60-70 kts. Down lower, 0-1 shear and effective helicity values will be sufficient for low level rotation, especially given strong stretching aided by 0-3km MLCAPE values pushing 250 J/kg. While the warm sector will be plenty dangerous itself, the aforementioned stalling outflow boundary may even result in an enhanced tornado threat from roughly Amarillo to Pampa if it is able to modify thermodynamically before any storms ride it. * Timing: Based on recent satellite/obs trends showing an area of strong pre-dryline convergence, surfaced based convection in our area should begin in earnest somewhere 30 miles either side of I- 27 by 2 PM. The worst of the threat will be over for the Panhandles by around 9 PM, though another round of storms could result in a flash flooding threat in the eastern TX Panhandle through midnight. * Caveats: There aren't many. The main caveat would be with a weak EML/cool-ish temps at h7 allowing too much convection, with storm interactions possible. However, in the Panhandles, when in doubt, discrete wins out (or at least quasi-discrete). * Threat Area: The greatest threat is confined by US 60 to the north, with all areas along and southeast of US 60 under the gun, including Amarillo, Canyon, Pampa, Canadian, Wellington, Wheeler, Clarendon, Miami, Claude, and Shamrock. * Hazards: The potential for strong tornadoes is the greatest concern, but everything from very large hail (bigger than baseballs possible), damaging straight line winds, and flooding are all parts of this event. Simpson PREV DISCUSSION... /Issued 1207 PM CDT Mon May 20 2019/ DISCUSSION... Please refer to the mesoscale discussion for updates on weather for today. As the upper level system moves into northern Kansas by tomorrow morning, residual thunderstorms may still be across the northern Panhandles, but precipitation chances will decrease through Tuesday. Active weather is expected to continue through the remainder of the forecast period. With a positive tilted trough in the west and a large anti-cyclonic flow in the east, above average PWAT values will funnel in Gulf of Mexico airmass into the region and with diurnal heating, we may see several days of thunderstorms across the Panhandles. Some of these storms could be strong to severe. High temperatures throughout the week into the weekend will rise into the mid and upper 80s. Meccariello AVIATION... MVFR/IFR conditions are likely throughout most of the 18Z TAF period. in conjunction with low cigs, TSRA conditions are most concerning from the start of the TAF period 03Z-06Z Tuesday. Localized chaotic winds are possible within a passing thunderstorm over ther TAF site. Low cigs will continue through 12Z Tuesday and then eventually clear out from south to north as the main low pressure system exits the region. TAf sites might become VFR before the end of the TAF period but exact timing of clouds will be updated in future TAFs. General winds will be ranging from SE-SW between 10-20 kts. Meccariello && .AMA Watches/Warnings/Advisories... TX...Flash Flood Watch through Tuesday morning for the following zones: Armstrong...Carson...Collingsworth...Donley...Gray... Hansford...Hemphill...Hutchinson...Lipscomb...Ochiltree... Roberts...Wheeler. High Wind Watch from Tuesday morning through Tuesday evening for the following zones: Deaf Smith...Oldham...Potter...Randall. OK...Flash Flood Watch through Tuesday morning for the following zones: Beaver...Texas. && $$ 88/88