200 FXUS63 KGLD 180016 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 616 PM MDT Mon May 17 2021 .SHORT TERM...(This evening through Tuesday night) Issued at 315 PM MDT Mon May 17 2021 Overview: A deamplifying upper level low, presently situated over the Desert Southwest, will slowly progress eastward across the southern Rockies tonight through Tuesday night. Through Tonight: An MCV (emanating from widespread convection yesterday evening), initially situated invof southern Greeley/Wichita counties at sunrise, currently (as of 21Z) situated invof Goodland.. will continue to weaken/deamplify as it lifts north toward the Nebraska border. Convection associated with this feature has steadily weakened during the past few hours, and will likely continue to weaken.. as activity progresses northward into an increasingly stable/capped airmass. Convection presently developing along the I-25 corridor in southern CO and central/ northern NM is anticipated to merge/coalesce into a NW- SE oriented line this evening.. approaching southwest portions of the area (i.e. Cheyenne county, CO and Greeley/Wichita counties, KS) around 04Z. However, the approaching convective line will encounter an increasingly unfavorable /worked-over/ airmass with northern extent.. and simulated reflectivity forecasts via the HRRR and NAM NEST suggest that rapid weakening is likely thereafter.. with activity more-or-less dissipating by 06-08Z. With the above in mind.. severe weather is not anticipated in the WFO Goodland CWA. Given that ongoing convection associated with the lingering MCV has already begin to weaken.. locally heavy rainfall /isolated flash flooding/ appears unlikely from this point onward. Tue-Tue night: Scattered convection may develop over portions of the area Tue aft/eve.. though recent runs of the HRRR and NAM NEST suggest that coverage is very much in question. Given that the thermodynamic environment upstream of the region will be altered (to some degree) by widespread convection this evening, and that forcing will, once again, largely be tied to mesoscale features (directly or indirectly) associated with convection.. considerable uncertainty persists. .LONG TERM...(Tuesday night through Monday) Issued at 332 PM MDT Mon May 17 2021 The long term period is looking drier than the start of the week with temperatures that are slightly above average. In spite of the drier pattern, chances remain nearly daily for rain and storms. Wednesday continues to see the upper level low that moved in from the west diffuse out into the larger flow as a ridge sets up in the east and a trough sets up in the west. This general upper level pattern then should persist through the remainder of the period leaving the Tri-State area in southwest flow. Near the surface, higher pressure will slowly move in through the remainder of the week. However, low pressure systems may come off the Front Range each day and could increase synoptic lift and rain chances. The air aloft looks to dry out through Friday which should lower cloud cover and chances for precip. However, guidance suggests that moisture gets pulled northward during the weekend though how much is uncertain. What this means is that Wednesday still looks to be a transition day with precip chances decreasing and cloud cover decreasing through the day. There is still a chance for storms and a few could become severe though confidence is not great in that regard. High temperatures are forecasted to be in the low 70's. Thursday and Friday are looking drier and warmer with high temperatures reaching up into the low 80's and sunnier skies during the day. There still could be some isolated storms that form with dewpoints reaching the upper 50's and lower 60's, but the low synoptic forcing and drier air aloft is expected to lower the overall coverage. Some may become severe with lapse rates approaching 8-9C and MLCAPE getting above 1000 J/KG but this is remains uncertain for now. This weekend and into Monday looks to be similar to the end of the week but with a few changes. First, moisture is expected to move in aloft from the south which would increase moisture available for storms that form though nothing producing extreme amounts. Secondly, the upper level trough is forecasted to move north and east and flatten the ridge. At the same time, lower surface pressure is forecasted to move into the northern Plains. Depending on how far south it moves, the low pressure maybe able to add some synoptic lift to the area. Finally, the cold front mentioned in previous forecasts is looking less certain on when/if it would move through the area with latest guidance suggesting Monday. Given the inconsistencies in the handling of this front and slow movement of the trough, I am currently leaning towards a warmer forecast for the weekend. Temperatures are currently forecasted in the upper 70's but expect this to vary some as the weather pattern becomes clearer. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 534 PM MDT Mon May 17 2021 The scattered showers currently extending along the northwest Kansas and southwest Nebraska border will continue lifting northward across over the next few hours with another area of more widespread showers and thunderstorms lifting northeastward out of southeast Colorado across western Kansas into southwest Nebraska between 06-12Z. Areas of fog are possible overnight. There is a lul in showers expected Tuesday morning with additional thunderstorm development expected generally after 17Z. GLD will see mainly MVFR conditions primarily due to low ceilings through 05Z. After 05Z, conditions will deteriorate and vary between IFR and LIFR due to low ceilings and visibility with fog rain showers with isolated thunder through 14Z. After 14Z, expect low ceilings and LIFR conditions to persist. MCK will drop from MVFR to IFR with intermittent LIFR between 06-19Z and thunderstorms mainly between 09-11Z. After 19Z, MVFR conditions are expected along with scattered thunderstorms. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...VINCENT LONG TERM...KAK AVIATION...LOCKHART