Area Forecast Discussion
Issued by NWS Goodland, KS
Issued by NWS Goodland, KS
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441 FXUS63 KGLD 200434 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 1034 PM MDT Thu Sep 19 2024 .KEY MESSAGES... - Dangerous fire weather conditions and significant reductions in visibility assoc/w blowing dust would accompany such a wind shift, if present. - Showers and thunderstorms will develop over much, or all, of the Tri-State area this weekend as a potent upper level low tracks eastward across the Rockies and Central Plains. An instance of flash flooding or river flooding is possible, mainly Saturday afternoon through Sunday morning. Barring a significant change in the evolution of the upper wave, severe weather is unlikely in the Goodland CWA. - Low temperatures in the mid to upper 30s are forecast for eastern Colorado by Monday morning. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 232 PM MDT Thu Sep 19 2024 Across the Tri State region this afternoon, skies are sunny as high pressure continues a transition through the area. Temperatures as of 100 PM MDT are ranging in the mainly in the 80s with some upper 70s in portions of northeast Colorado. With much of the forecast area still on the east side of the surface ridge, the gradient remains northerly with gusts up to 20-25 mph in spots. Areas in Colorado are lighter and should transition to light/variable by sunset. The main wx concerns for the short term period will be the potential for near critical to locally critical fire wx conditions over portions of northeast Colorado for Friday afternoon, increased rw/trw chances late Friday into the upcoming weekend. Weekend precip chances may bring locally heavy rainfall that could bring about flooding concerns. The latest RAP40 500mb analysis is showing zonal flow aloft as a large ridge resides over the lower two thirds of the country. Guidance carries this ridge slightly south and east on Friday, allowing for a transition to SW flow aloft. At the surface, high pressure working through the area tonight will provide tranquil conditions as winds will be light, but will slowly transition to southerly by Friday morning as the ridge moves east of the area. There will be an inverted trough setting up over eastern Colorado that will begin to enhance the southerly flow, especially over our Colorado counties. This gradient, combined with dry conditions setting up on southerly flow, will create increased fire wx concerns for portions of northeast Colorado. Please refer to the Fire Weather section below for more information. Winds may also create some blowing dust concerns and will have to be monitored. There will be a weak shortwave that rounds the northern periphery of the upper ridge Friday night moving up into Kansas. The aforementioned trough to the west will also shift east Friday evening. 20% chance of rw/trw is possible for areas along/east of Highway 83. Weak instability and the NamNest is showing some scattered potential towards the 06z Saturday timeframe. Going into this weekend, guidance brings a closed upper low slowly out of the Desert SW and slowly into the central Rockies. The ridge to the east will slow the progression of the system towards the Plains region after 18z Saturday. 700/850mb low ahead of the 500mb parent will slide east through the CWA Saturday night into Sunday morning. Guidance brings the 500mb low slowly E/NE through the CWA through Sunday, clearing east going into the evening hours. The result of this system and is slow trek across the area, will be a 36-hour period of persistent steady rainfall with rw/trw. The latest WPC QPF for this time remains fairly closer to previous forecast with the potential for a range from 1.30-1.70 inches area- wide. This steady rainfall combined with some localized thunderstorms could bring amounts exceeding 2 inches. This could create some localized flooding concerns that may affect areas river/streams. This will have to be monitored for potential flood watch. WPC does have the entire CWA under a Marginal Risk for excessive rainfall. Gusts could approach the 25-35 mph on the backside of the exiting system Sunday/Sunday night. For temps, highs Friday in the upper 80s to lower 90s will give way to 70s and 80s on Saturday. Going into Sunday, mainly 50s to lower 60s are expected as CAA brings in a nice round of cooler temps(850 mb temps during the day range around +5c). Overnight lows tonight will range in the 50s, 50s/60s Friday night, but for the upcoming weekend, mainly 40s Saturday night and for Sunday night, mid to upper 30s in Colorado and along the border, with lower 40s east of there. Areas Highway 27 and west may have to be watched for a potential Frost Advisory. && .LONG TERM /MONDAY THROUGH THURSDAY/... Issued at 101 PM MDT Thu Sep 19 2024 For the extended period, the latest runs of the GFS/ECMWF both show a cutoff 500mb set up in the Desert SW, allowing for NW flow aloft initially. By midweek, amplified ridging occurs allowing for a return to SW flow aloft, with the low still over the southwest portion of the country. The two models do differ some on the placement of the system during this time. At the surface, high pressure will set up east of the area, with an inverted trough over eastern Colorado. As the upper low swings south through the Rockies on Mon-Tue, there is a 20-30% chance for rw/trw to occur. Guidance has the pop chances out to the Highway 25 corridor, but should be focused closer to inverted trough although it does shift a bit E/SE going into Tuesday. There is a weak shortwave that could work into the upper ridge midweek, but after the precip chances through Tuesday evening, the rest of the week is mainly dry. 850 temps through Tuesday top off around +20c, increasing into the 20s midweek as the upper ridge becomes more assertive over the Plains region. This will allow for a slow increasing temp trend, if only by a few degrees from Monday`s to Friday`s highs. For temps, the Tri State area will see mainly 70s for highs each day. There could be some locales during the day Monday/Tuesday that may only see the upper 60s. Tuesday`s numbers will be highly dependent on how fast cloud cover breaks to allow mostly sunny skies during the afternoon hours. Overnight lows will range mainly in the 40s each night, warmest areas east of Highway 25. Thursday night could have low 50s stretch as far west as Highway 25, but cloud cover/wind dependent. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 1032 PM MDT Thu Sep 19 2024 VFR expected to prevail at both KGLD and KMCK through the TAF period. Surface winds will be light tonight, increasing from the southeast on Friday. && .FIRE WEATHER... Issued at 232 PM MDT Thu Sep 19 2024 Across much of our northeast Colorado on Friday afternoon, RH values are expected to drop into the mid teens to the lower 20s. There is an inverted trough over eastern Colorado that will strengthen by the afternoon hours, creating southerly gusts around 25-30 mph. This will create near critical to localized critical fire wx conditions, especially over western portions of Kit Carson and Cheyenne counties. This will have to be monitored for potential red flag conditions/warning by next forecast shift. && .HYDROLOGY... Issued at 232 PM MDT Thu Sep 19 2024 An efficient 850mb LLJ is expected to start setting up around 21Z Friday and continue until Sunday morning. This LLJ will provide a moist conveyor belt from the Gulf of Mexico into the High Plains. As mentioned above, an organized low pressure system will move into the region Saturday, creating a moderately strong forcing mechanism to start precipitation. Precipitation looks to start in the eastern CWA Friday evening, intensifying Saturday afternoon, and begin weakening Sunday before moving out of the area by Sunday evening. Between 21Z Saturday and 18Z Sunday, nearly the entire Tri-State area will see at least a couple tenths of rain with the potential (~25%) of seeing 2+ inches in that timeframe. If the higher amounts do occur, especially in the eastern CWA, there will be increased flooding concerns. Concerns for flash flooding are low (<10%) with the potential for areal flooding being slightly high at around 20%. There could result in a precipitation range from 1.30-1.70" with localized higher amounts in convection. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...JN LONG TERM...JN AVIATION...024 FIRE WEATHER...JN HYDROLOGY...JN