Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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209 FXUS63 KGLD 210855 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 255 AM MDT Sat Sep 21 2024 .KEY MESSAGES... - Showers and thunderstorms will develop over majority of the Tri-State area this weekend. Both severe weather and flooding chances are very low (<5%). - Low temperatures in the mid to upper 30s are forecast for eastern Colorado by Monday morning. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 218 PM MDT Fri Sep 20 2024 Current observations continue to show some streaks of mid- level moisture streaming from the southwest with storms developing in Southwestern Kansas. The Tri-State area is more in a dry streak which is keeping cloud cover and precip chances low. There should be some sprinkles and showers for Greeley, Wichita, Logan, and Gove counties, but not anything that should be impactful. This evening and tonight, skies should clear out with the moisture stream shifting more east/south. Winds should lower to around 10 mph. Even with the clearing skies and lowering winds, lows are forecast to remain fairly warm in the 50`s and 60`s as the southeasterly flow across a majority of the area has brough dewpoints in the 50`s and 60`s to the area. Tomorrow, the upper low currently near the CA/NV border is forecast to shift east to near the Four Corners region during the day. This will help push a surface cold front through the area during the morning. With the frontal passage, winds will strengthen to 20-25 mph with gusts up to 35 mph and bring in some cooler and drier air to the area. Meanwhile, additional mid-level moisture is forecast to stream in from the northwest and help saturate the air column. The issue is that by the time the air saturates, the front is forecast to be in the southern part of the area. This will limit the better rainfall to the far southern portions of the area. So for most of the area, temperatures would likely peak around the noon hour, and then remain steady or cool as cloud cover increase and colder air advects in from the north. Rain looks to be limited through the afternoon except for far southern portions of the area. For the evening and overnight hours, the upper low is forecast to begin swinging through the region. This will provide some upper level support for showers and storms to develop along the higher terrain in Eastern Colorado. Showers and storms should then move through across the area with the saturated air unless the higher pressure can move in quickly and undercut storms. Once this line moves through the area, precipitation chances and amounts are forecast to drop off as subsidence begins to take over and drier air is forecast to move in the mid-levels. Sunday, a dreary day is forecast as the lower levels remain saturated and allow for fog and mist to develop. With the cooler air and persistent cloud cover, highs are forecast to only be a few degrees warmer than the lows in the 50`s. Temperatures may end up being dictated by how low/high the dewpoints are. Winds are forecast to slowly lower through the day as the higher pressure moves over the area. The evening and overnight hours are forecast to see skies slowly clear as the upper low pushes east of the area and drier air moves in. This could cause a potential issues where parts of Eastern Colorado could hit 36 degree or less for the first time this season. Looks to be dependent on how low the dewpoints will get with clear skies and light winds. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 245 AM MDT Sat Sep 21 2024 Monday: Guidance suggests that troughing/cyclonic flow aloft will persist over the Central Plains.. on the eastern fringe of an amplifying upper level ridge along the Pacific Coast. Clear skies in the wake of the departing wave may eventually give way to increasing cloud cover late Mon-Mon night.. via cyclonic shear vorticity on the eastern periphery of a strong (~100-115 knot) northerly upper level jet extending southward from Alberta and Saskatchewan to the central Rockies. Sunny skies during the day will foster a warming trend. Expect temperatures warmer than Sunday (albeit still cooler than average).. ranging from the mid 60s (east) to mid 70s (west). Tuesday-Friday: 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. Solutions from current operational runs of the GFS/ECMWF continue to diverge on Tuesday.. albeit less-so than yesterday. Both models suggest that [1] the aforementioned ridge will shift eastward across the Intermountain West (Tue), Rockies (Wed), Central/Northern Plains (Thu) and Mississippi River Valley (Fri).. [2] 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 and [3] that said low will be subsumed by /trapped within, cut-off beneath/ the ridge. The ECMWF suggests that upper low development and subsumption will occur over the Central-Southern Plains.. the GFS suggests it will occur over the OH Valley. Steering the forecast toward climatology appears to be the most prudent course of action at this time. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1036 PM MDT Fri Sep 20 2024 VFR expected to prevail at both KGLD and KMCK through the TAF period. A cold front will shift winds to the northwest then northeast early Saturday morning, gusty through the afternoon. Some showers may begin to move into the area towards the end of the TAF period Saturday night, but with minimal, if any, impacts. && .HYDROLOGY... Issued at 323 AM MDT Fri Sep 20 2024 The forecast continues to call for precipitation this weekend with the low levels becoming saturated through low level moisture advection from the southeast and mid-level advection from the southwest. However, forecast amounts continue to trend down as the best forcing does not appear to line up with when the air is most saturated. The front is forecast to move through early Saturday before the air can saturate. The best chance for rain during the day Saturday is for southern parts of the area as the front passes. Rainfall amounts and chances will be better if the front stalls in the southern portion of the area. The next good chance for rain is overnight Saturday into Sunday as the upper low swings through and brings a chance for showers and storms off the higher terrain in Eastern Colorado. However, a mid-level dryslot may interfere with this round and weaken chances. Amounts around a quarter of an inch or less are suggested with this kind of a setup for the whole event. If the forcing and moisture align better, than amounts of one to two inches become more likely, especially if the front stays over southern parts of the area. Flooding looks to be possible in scenarios where the front over performs and produces a couple of inches early, mainly from Wallace, KS to Norton, KS and south. Overall chance is around 5 to 10%. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...KAK LONG TERM...Vincent AVIATION...024 HYDROLOGY...KAK