Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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184 FXUS63 KGLD 201722 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 1122 AM MDT Mon May 20 2024 .KEY MESSAGES... - Enhanced Risk for severe storms this evening from Yuma County east along the Kansas and Nebraska border area. A Slight to Marginal Risk elsewhere. In the Enhanced Risk area, supercells capable of producing large to very large hail, damaging winds and tornadoes will be possible, with the risks elsewhere being large hail and damaging winds. Locally heavy rainfall and flash flooding will be possible in the Enhanced Risk area, mainly in southwest Nebraska. The severe risk will continue well into the overnight hours. - Patchy frost possible in northeast Colorado late Tuesday night and early Wednesday morning. && .UPDATE... Issued at 1117 AM MDT Mon May 20 2024 Based on the latest CAMs(HRRR, RAP and NamNest), have decided to add Dundy county in SW Nebraska to the ongoing Flood Watch. Still looking for a start time around 00z Tuesday, initiating in Colorado, overspreading SW Nebraska before lifting out of the CWA. No other changes at this time. Will monitor guidance for possibly adding Yuma county in Colorado to the current Watch. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Issued at 220 AM MDT Mon May 20 2024 Cold front is making its way through northeast Colorado early this morning and will continue to slowly makes its way through the forecast area today. Initially winds will be northwest, but by this afternoon will start to see them turn northeast and by late this afternoon moist, easterly upslope winds will be in place across a majority of the forecast area. A shortwave trough embedded in the southwesterly flow aloft will move into eastern Colorado late this afternoon and across the forecast area tonight, providing synoptic scale lift for convection. Storms are forecast to enter the northwest corner of the area, Yuma County, by around 00z, in a weak to moderately unstable environment of 1000-2000 j/kg, and deep layer shear values of around 50 kts. CAMs strongly suggest supercells will be possible as they move east along the Kansas and Nebraska border area this evening in multiple rounds. Best tornadic environment will probably be in the early evening when a surface based supercell is possible, but with increasing CIN as they track east storms will more likely become elevated and be capable of producing large to very large hail as well as damaging winds. The severe risk may extend well into the overnight hours with another shortwave trough moving through. In addition to the severe risk, heavy rain will be possible, especially across southwest Nebraska where higher percentile QPF shows 1-2 inches possible. Since heavy rain fell in Hitchcock/Red Willow counties last night and Sunday morning, decided on a Flood Watch since those counties are already seeing nearly saturated conditions and will be more susceptible to flooding with the additional heavy rain. Rain will continue into Tuesday morning for areas north of Interstate 70, but more stratiform with stable conditions and surface winds turning northwest as the front surges south again. This should allow some afternoon sun and temperatures to warm into the 60s and 70s. Another shortwave trough comes out of Colorado Tuesday night with another round of showers and isolated thunderstorms. Instability is very weak and no severe storms are anticipated on Tuesday. Additional QPF amounts are generally between a tenth and a quarter of an inch with this system. Precipitation winds down overnight but clouds may persist. Depending on the amount of clearing that occurs, some patchy frost will be possible in northeast Colorado with lows in the mid to upper 30s. On Wednesday will see zonal flow aloft with dry conditions during the day and high temperatures in the low to mid 70s. Another shortwave moves across Wednesday night with scattered showers and isolated thunderstorms, but once again instability is weak and no severe storms are expected. Rainfall amounts Wednesday night are currently forecast to be less than a tenth of an inch. Low temperatures will be in the mid 40s to lower 50s. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Issued at 133 AM MDT Mon May 20 2024 An active weather pattern continues into the long term period as a series of shortwaves move through the region, providing additional chances (generally around 20-30%) for showers and storms. At the start of the long term period, an approaching shortwave trough is lending to southwesterly flow aloft as an upper low is centered near the borders of ID/WY/MT. A surface low is forecast in the lee of the Rockies by Thursday afternoon-evening with model guidance suggesting convection developing out ahead of it. Friday will again see chances for showers and storms as another shortwave progresses through the flow during the afternoon-evening. Lesser confidence as we head into the weekend; however, guidance keeps shower/storm chances with a wave moving through in the Saturday- Sunday timeframe. As mentioned previously, better moisture and instability is forecast to reside across eastern portions of the area during much of the period. Regarding temperatures, highs are forecast in the low to middle 80s for Thursday, cooler in the 70s for Friday, followed by a mix of middle 70s to low-middle 80s through the remainder of the long term. For low temperatures, expecting generally middle 40s to low-middle 50s. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1058 AM MDT Mon May 20 2024 Both sites have the potential to see convection occur later in the forecast period. Timing of this will shift as the onset occurs and updates sent as needed. For KGLD, mainly VFR conditions are expected through the forecast period. There could be a period of MVFR conditions from 02z-05z Tuesday with ceilings lowering as the potential for VCTS increases. Winds will be veering through the period with north 10-20kts through 20z, then shifting east-southeast. By 09z Tuesday, becoming southwest around 10kts and eventually north-northwest around 15-25kts from 12z onward. For KMCK, a mix of MVFR/IFR ceilings is expected through the forecast period. 03z-07z Tuesday VCTS is possible along with light to moderate rainfall. Visibility could drop into the 5-6sm range. Winds, mainly east-northeast 10-15kts through 13z Tuesday then northwest 15-25kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...Flood Watch from 6 PM MDT /7 PM CDT/ this evening through late tonight for NEZ079>081. && $$ UPDATE...JN SHORT TERM...JN LONG TERM...CC AVIATION...JN