747 FXUS63 KGLD 201109 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 509 AM MDT Sun Aug 20 2023 .SHORT TERM...(Today through Wednesday Morning) Issued at 247 AM MDT Sun Aug 20 2023 Ridging remains across the area along with warm temperatures essentially east of the Colorado state line. Temperatures ranged from the mid 60s in Colorado to the low 80s over eastern portions of the areas. Guidance is hinting at an area of fog/stratus to develop along a Yuma County to Sheridan county corridor around sunrise so went ahead and added in patchy fog for this time period as a plume of higher dew points pushes into the area briefly along with easterly winds which is typically favorable for fog/stratus development. As for today the hot temperatures continues. The same theme with dew points exceeding expectations again continued Saturday, so I will keep going with this theme for my forecast especially for the east. As a result of this, I have went ahead and issued a Heat Advisory for Norton and Graham counties as heat indices are forecasted again to reach at least 105 degrees. Across western portions of the area, a surface low is forecast to develop across north central Colorado. As this occurs winds will become breezy to gusty from the south gusting to 35 mph at times. Drier air will work into the area allowing RH values to fall into the low to mid teens. The inherited Red Flag Warning looks on track for the eastern Colorado counties. Into western Kansas, mainly Cheyenne through Greeley. RH values look to fall into the mid teens, however winds look to be more iffy at 20- 25 mph. There is a chance that they could be a little bit stronger if the surface low sets up further east than currently forecast so this will be something that will need to be watched through the day. Overnight lows are currently forecasted int he mid 60s to mid 70s across the entire area as winds will switch to the SW. Monday, breezy SW winds will be common across the entire which will help air temperature warm up quite a bit across the area as the ridge remains. High temperatures are currently forecast to range form the upper 90s to mid 100s. Confidence is high enough to go ahead and issue another Heat Advisory for counties along and east of Highway 83 where dew points in the upper 50s to low 60s are forecast to remain. As mentioned winds will be stronger across more of the area, the main question will be how warm will western counties get and how dry. RH values are currently forecasted in the upper teens to low 20s west of Highway 25. Uncertainty regarding RH values have precluded me from issuing a Fire Weather Watch as this, although the winds are for sure there; upcoming forecasts will need to be monitored for any potential lower dew point trends. Winds overnight will remain breezy which will again help keep overnight temperatures in the upper 60s to mid 70s across the area. Tuesday, a bit more uncertainty exists with temperatures and dew points. Highs are again forecasted to be in the upper 90s to mid 100s across the area. There are however signals that dew points will be lower across the entire area. If this is the case then heat indices will be lower than actual air temperatures. Currently have heat indices up to 103 forecasted across Norton and Graham counties. If an upward trend continues for these two counties then an Excessive Heat Warning may need to be considered as this would be the fourth consecutive day of heat indices in excess of 105 degrees. Winds will again be breezy across the area, gusting up to 40 mph. The main question for fire weather though is again RH values as they are currently forecasted in the upper teens to low 20s across nearly the entire forecast area. Again this will need to be monitored for potential fire weather highlights due to this prolonged period of hot and dry conditions. Overall for the short term period, hot conditions will continue through at least the middle of the week. A few near record to record highs are possible today and Monday (see the climate section below for more info on this). .LONG TERM...(Wednesday through Sunday) Issued at 112 AM MDT Sun Aug 20 2023 The latest runs of the GFS/ECMWF continue to show 500mb ridging over the central Mississippi River Valley midweek timeframe, but begins to retrograde and amplify over the central/southern Plains as well as the eastern Rockies late Friday through the upcoming weekend. Previous runs of this guidance did have zonal flow by this time. The change will impact the push of mid level moisture into the cwa as it rounds the upper ridge from the west-southwest. At the surface, low pressure will set up along the Front Range Wednesday, pushing east into the Plains region, meandering over Kansas for the remainder of the forecast as a front. The boundary will be the focus for precipitation over the area late week. The movement/placement of the front will shift the wind regime from S/SW for Wednesday and Thursday, to N/NE on Friday then easterly for next weekend. These winds will allow for an increase in low level moisture, with PW values increasing to around 1.2" to 1.5". With the boundary layer being extremely dry leading up to the increased low level moisture influx late week, looking for locally heavy rainfall to occur. Low SBCape/MUCape values during this time, but DCape does increase to 1400-1500 j/kg with inverted-V soundings suggests if any storms do occur, wind will be the main threat. This weekend with best PW values, little to no instability showing up, so expecting mainly rain. Western locales will see the best chances for rw/trw, especially during the daytime hours, but could overspread the CWA going into the evening/overnight periods. Based on the latest 850mb temps, Wed-Thu will be the warmest days in the extended. Gradient ahead of the boundary/front will bring gusts up to 25-30 mph. With humidity ranging in the low to mid 20s, not concerned about fire weather, but should be monitored nonetheless as subsequent drying leading to the midweek timeframe could lower the potential min RH expected each day. For temps, the region will see the midweek timeframe as the warmest portion of the extended forecast. Highs on Wednesday and Thursday will range from the mid 90s west into the low 100s east, especially east of Highway 83. For Friday on into next weekend, cloud cover and expected precipitation will bring a wide range Friday from the lower and mid 80s west, to the lower and mid 90s east. Lower and mid 80s on Saturday will give way to mid 80s area-wide Sunday. Heat indices will remain around/just below forecasted highs. Overnight lows Wednesday night will have a range from the mid 60s west into the mid 70s east. There will be a cooling trend for the remainder of the week into next weekend, where mid 50s to lower 60s are expected. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) Issued at 451 AM MDT Sun Aug 20 2023 Fog and stratus potential exists for the start of the period with MVFR ceilings already occurring at KMCK. Moist low levels at KGLD should support this same potential as well through at least 14-15Z; there may be a very narrow corridor of IFR to LIFR visibilities on the leading edge of the stratus. Stratus and or fog should dissipate mid morning. Will then be watching for winds to shift to the south at KGLD and gust up to 25 knots during the afternoon. Winds at KMCK will be more SSE gusting near 20 knots. Forecast soundings do show a strong signal for LLWS Sunday night into Monday morning so will be including in this TAF. && .CLIMATE... Issued at 247 AM MDT Sun Aug 20 2023 Record Highs For August 20th: Goodland: 104 degrees in 1987 McCook: 101 degrees in 2007 Burlington: 101 degrees in 2001 Hill City: 109 degrees in 1911 Record Highs for August 21st: Goodland: 102 degrees in 1943 McCook: 104 degrees in 1929 Burlington: 103 degrees in 2003 Hill City: 105 degrees in 1918 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Heat Advisory from noon to 8 PM CDT Monday for KSZ003-004-015- 016-029. Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for KSZ004-016. CO...Red Flag Warning from noon today to 7 PM MDT this evening for COZ252>254. NE...Heat Advisory from noon to 8 PM CDT Monday for NEZ081. && $$ SHORT TERM...Trigg LONG TERM...JN AVIATION...Trigg CLIMATE...Trigg