Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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518 FXUS63 KGLD 161123 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 523 AM MDT Mon Sep 16 2024 .KEY MESSAGES... - Warm and windy conditions are forecast for today and Tuesday with highs generally around 90. Winds are forecast to gust to 30-40 mph today and 35-50 mph tomorrow. - Storms are possible during the afternoon/evening hours today and tomorrow, though tomorrow has the better chance (40-80%). Severe weather is possible tomorrow with gusts up to 65 mph possible. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 308 AM MDT Mon Sep 16 2024 The short term forecast remains active with strong winds the next two days and chances for storms. Early morning storms continue to impact eastern portions of the area, largely driven by the presence of low/mid level moisture and lower level convergence cause by the LLJ. Storms have been sub- severe and the increase in winds saw earlier this evening has not been occurring so the jet does not appear to be mixing down as efficiently. These storms should leave the area around or shortly before sunrise. For the morning and early afternoon hours, skies are forecast to initially clear off underneath southwest flow aloft and allow temperatures to warm around 90. Meanwhile, the upper low/trough over the Western CONUS is forecast to begin shifting slightly to the east. This will tighten the height gradients over the area and allow winds to strengthen to around 30 kts in the 850-700mb layer. With the heating and mixing through the day, this will allow for surface wind gusts up to 35-40 mph through the day. Later in the afternoon and during the evening, the area will have another chance for storms with lower pressure along the Front Range creating a convergence zone along the Palmer divide as the southwest flow brings in some mid-level moisture from the southwest. The low level jet is forecast to develop again during the evening hours and help carry storm chances east across the area. Coverage is currently forecast to be isolated to scattered with the overall lack of forcing and drier air in the lower levels. But similar to recent days, will need to keep an eye for how much the jet enhances storm development and maintenance. Storms should generally remain sub- severe with gusts generally below 50 mph, but a storm or two could produce a gust up to 60 mph. I`m more worried about a scenario similar to yesterday evening where the jet may briefly mix down before the inversion fully sets up. In short, expect another windy evening. The rest of the night will see storm activity slowly taper off and lows drop into the 60`s while winds remain somewhat elevated around 15-20 mph as the upper trough moves closer to the area. Tuesday, the upper low is forecast to move through the Rockies. This will continue to tighten the height gradients with winds around 40 kts possible in the 850-700mb level. With clear skies to start, ample mixing should occur and allow for surface wind gusts around 35 to 50 mph through the day. Temperatures are forecast to warm to around 90 again no warm air advection as the system nears. Widespread/concentrated blowing dust is not expected as local research suggests the winds are just weak enough with 2km lapse rates to steep to contain any dust. However, any recently plowed field or source region for dust may see localized visibility reductions. Later Tuesday afternoon and into the evening, the upper trough and surface low pressure system are forecast to swing through the area. With the upper southwest flow bringing in moisture and the brief southeasterly surface flow forecast to bring in some moisture, storms are expected to fire up along the Palmer Divide and then track east through the area. As long as storms don`t gust out and surface winds ahead of the line of storms maintain a more southeasterly orientation, there should be enough moisture and lift to have decent storms move through as a line or multiple clusters. This will give the area a good chance for rain with POPs generally in the 40-80% range. Severe storms will be possible more with the earlier storms in Eastern Colorado and counties just to the east when there is a higher chance of storms being organized or discreet. Overall instability is forecast to be marginal (MUCAPE around 1500 J/KG) with effective shear low to generally unidirectional winds. However, the overall strong flow and roughly linear mode will make it possible to see a few gusts to 65-70 mph. As a side note, previous events have shown that winds tend to be sub-severe when the overall surface flow is strong until near or after sunset. In short, a chance for marginally severe storms moving across the area is possible. Tuesday night should see storms exit the area around or shortly after 2-3am central time. As the upper trough continues to lift north, the surface gradient is forecast to weaken as the main low pressure center lifts north as well. As long as the inversion sets up, the stronger winds aloft should also decouple through the night and allow winds to lower getting close to sunrise. This should allow for lows in the 50`s for any locales that have storms clear out earlier in the night. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Issued at 136 AM MDT Mon Sep 16 2024 The latest runs of the GFS/ECMWF both show with the passage of the system for Tuesday night, upper ridge re-amplifies over the Plains region setting up SW flow aloft for the two day period. At the surface, there will be a low over eastern Colorado that meanders eastward on Wednesday w/ a front extending over northern tier zones. Guidance on Thursday sets up another low over Colorado on Thursday as well, but this system will not push east until Friday. So with SW flow aloft for Wed/Thu and a southerly flow during the daytime hours, the region will see near to above normal warmth each day. The position of the low each day will dry conditions for portions of the area each afternoon. RH values Wednesday will range in the mid teens to lower 20s from Highway 27 and west. On Thursday, mid and upper teens spread further east towards the Highway 25 corridor. As a result, increased fire wx conditions will ensue. Winds each day remain below criteria(25 mph). For Friday on through Sunday, both models will bring the broad shortwave over the western portion of the country into the Rockies and lifting E/NE by Sunday night. There is some inconsistency as to the timing/placement of the upper system which will affect QPF potential/duration. A 700mb trough/low will traverse the CWA during this time, interacting with a cold front to trigger rw/trw. High pressure to the east will stall the eastward advance of this system. This will allow for decent precip chances Fri(20-30%), Fri night(40- 60%), Sat(30-40%), decreasing to 20-30% Saturday night as the system begins to lift out of the area. Lingering 15% chances in the far northeast early Sunday morning before dry wx ensues late Sunday onward. While the potential for strong storms is possible as the front moves through the area, will wait to see how the system progresses to highlight further. System track favors the highest QPF potential in the E/NE zones where WPC QPF has over an inch possible. For temps, looking for highs on Wednesday to range in the 80s, with a mix of 80s and 90s on Thursday. On Friday as a cold front begins to work into the area, a wide range from the upper 70s to the upper 80s is expected, warmest along/east of Highway 25. For the upcoming weekend into next Monday, a cool down with 70s expected. Overnight lows will transition from the 50s and 60s Wednesday and Thursday nights, to a mix of 40s to lower 50s(east) from Saturday night onward. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 518 AM MDT Mon Sep 16 2024 For KGLD... VFR conditions are forecast for the period. Winds will generally remain from the south around 15-20 kts with gusts up to 30 kts. Will need to be careful this evening (0-6Z) as there is a 20% chance for a passing shower/storm and a chance that winds may briefly get stronger similar to yesterday (but more likely to be limited to 40 kts or less). For KMCK... VFR conditions are forecast through the period. winds will remain roughly from the south at 15-20 kts with gusts to 30 kts. There is a 20% chance for a storm to move through during the 00-12Z timeframe from the west. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...KAK LONG TERM...JN AVIATION...KAK