Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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527 FXUS63 KGLD 221121 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 521 AM MDT Sun Sep 22 2024 .KEY MESSAGES... - Showers will continue through the mid-day. Total rainfall amounts look to be around 0.25 inch for most of the area. Hazardous weather is not expected. - Low temperatures in the mid to upper 30s are forecast for eastern Colorado by Monday morning, potentially allowing for some patches of frost. There is a concern for fog formation Monday morning, too. && .SHORT TERM /THROUGH MONDAY/... Issued at 247 AM MDT Sun Sep 22 2024 Showers are moving across the area, albeit with less coverage than was forecast 24+ hours ago. These showers, moving from the southwest to the north and northeast and are expected to persist until the late morning. An additional surge of dry is starting to move into the area from the southwest, as easily seen at the 320K level, which will limit the amount of QPF these showers can produce. Around 18Z, the low will start moving out of the area. The following pressure rises and additional dry air in lower levels will end the showers in the southwest first, with the northeastern CWA seeing rain last. By 21-23Z, all of the rain is expected to have moved out of the area. QPF totals from this event look to be around 0.25 inch, significantly lower than what many previous forecasts had. The lower amounts of precipitation have also kept overnight temperatures notably warmer, which gives most of the CWA the potential at a midnight high today, and will increase day-time temperatures slightly. 24 hour maximum temperatures look to be in the mid 50s to low 60s while the day-time highs will be +/-3 degrees of the 24 hour maximums. The cool temperatures are due to the northerly winds, thick cloud cover, and slight evaporational cooling. As the low moves out of the area this afternoon/evening, a surface high will traverse the CWA. Winds will weaken, shift from northerly to southerly, and the sky will clear out as a result. This creates an interesting setup overnight where two things could happen, a mixture of both, or neither (which is looking more possible). Potential one is patchy to widespread fog; with clear skies, light winds, and recent precipitation, the environment is primed for fog formation, with a couple of catches. The light winds that will exist won`t be easterly (upslope) for long, if it all, lowering the fog potential. Also, while an inversion does look likely to form, surface layer moisture looks to be too dry from a lack of heavy precipitation. Most likely scenario is valleys and locations sheltered from the light breezes will see fog form. Confidence in patchy fog is around 20-25%, widespread fog is around 5-10%. Potential two is frost formation, mainly northwest of a line from Kit Carson, CO to Wray, CO. The same conditions that make fog possible overnight could allow for temperatures to drop into the mid 30s, allowing light, patchy frost to form. The big unknown, and limiting factor, for the frost potential is what the dew points will do overnight. If dew points remain around 40 overnight, the potential for frost is near 0. However, if the dew points drop to the mid 30s, patchy frost becomes more likely. Confidence for patchy frost forming is around 15%. As mentioned before, there is a chance (~10%) that both could occur; we could see fog in the eastern CWA and frost in the western CWA. The potential for neither of these possibilities to occur is around 30%. Southeast of the aforementioned line will cool into the low to mid 40s overnight. Monday will see the benefits of the surface high as clear skies and weak southerly winds will dominate. Highs could rebound pretty quickly and warm into the low to mid 70s. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 159 AM MDT Sun Sep 22 2024 Below average forecast confidence. Forecast confidence typically decreases with range -- `below average` in this context is intended to communicate a further reduction in confidence associated with /inherent to/ increased pattern complexity -- e.g. patterns with cut-off waves, multibranched wave interactions and potentially significant forms of constructive/destructive interference or feedback. Guidance continues to diverge Tue-Tue night.. as a pronounced upper level ridge progresses east across the Intermountain West and Rockies. Solutions via recent (00 UTC 09/22) operational runs of the GFS/ECMWF are consistent only in the sense that they remain inconsistent. Both models suggest that some degree of northern and southern stream jet phasing (or interaction) within a complex split flow regime on the eastern periphery of the advancing ridge will foster the development of a closed low somewhere invof the Central/Northern MS River Valley Tue night. Poor model-to-model and run-to-run continuity essentially precludes further discussion, other than to say that.. whatever the outcome, hazardous weather seems unlikely. Steering the forecast toward climatology remains the most viable course of action at this time. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 513 AM MDT Sun Sep 22 2024 Showers moving through the region will lightly impact flight categories at both KGLD and KMCK. KGLD will likely only see the showers over the site until about 13Z. After 13Z, vicinity showers are expected and ceilings will start lowering, down to around 2,500-3,000 feet around 15Z. By the afternoon, showers will be gone, ceilings will have recovered, and by 22Z, light variable winds are expected for the rest of the period. For KMCK, the showers are approaching the airport currently and will persist until about noon local. After that, winds will be light for the remainder of the period. Ceilings are not expected to lower below 3,500 feet for KMCK. However, at both sites, heavier pockets of rain can temporarily lower visibilities down to around 3-5 SM. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...CA LONG TERM...Vincent AVIATION...CA