937 FXUS63 KDDC 221716 AFDDDC Area Forecast Discussion National Weather Service Dodge City KS 1116 AM CST Mon Jan 22 2024 .KEY MESSAGES... - Dense fog and freezing fog possible (30-50% chance) from Dodge City to Garden City and points north, mainly 6 to 9 AM time frame. - There is a much greater chance (> 60% chance) of widespread dense fog and freezing fog late this evening through the first half of Tuesday. - Prolonged freezing fog north and west of a Garden City to Jetmore to La Crosse line will likely(> 60% chance) result in rime ice on exposed surface and perhaps some slick spots on bridges and overpasses. - Light rain and freezing rain late Tuesday Night into Wednesday with minimal impacts expected as temperatures slowly warm above 32 degrees through the event. There has been a very slight warming trend in the forecast temperature during this event supporting more plain cold rain vs. freezing rain. && .SHORT TERM /THROUGH TUESDAY/... Issued at 405 AM CST Mon Jan 22 2024 The main forecast challenge and most impactful element in the Short Term period will be fog/freezing fog as low level moisture continues to transport northward toward the colder near surface airmass and snow cover areas. The ground across all of southwest and west central Kansas is either snow-covered or bare areas with soil temperatures around 30 degrees all the way down to about 8 inches. This in itself is an important ingredient for widespread, prolonged dense fog potential with dewpoint temperatures of low to mid 30s degF on the way to our region. The latest 09Z (3 AM CST) observations were showing 32-34F dewpoints south of DDC across far northwestern Oklahoma into the eastern Texas Panhandle. So far, it has mainly been low stratus within this moist axis, mainly due to continued surface winds in the 12-18 mph range. We are monitoring the western edge of this surface moist axis as this will be where the best juxtaposition of low level moisture, cold surface temperatures, and light winds will be...mainly along and west of a Meade to Dodge City to Ness City line. East of there, temperatures will be slowly warming along with the dewpoint temperature through the early morning hours. Latest HREF model shows 1/4 mile visibility probabilities of 50% or greater expanding in coverage after 09Z with a 3-hr window of highest probabilities 13-16Z this morning more or less focused on the central portion of the DDC CWA, including Cimarron, Dodge City north to Ness City west to Garden City. We plan to wait until there is higher confidence in areal extent of this morning's dense fog potential before issuing a headline, but one may be necessary. Regardless, low level moisture of widespread lower to mid 30s dewpoints will continue to advance northward across much of Kansas and wind speed/direction at the surface will become increasingly favorable through the day today for fog development. Wind direction will gradually attain some easterly upslope development, while at the same time weakening in speed, such that by sunset tonight, already low temperature-dewpoint spreads west of Highway 283 will likely become even lower to saturation quite early in the evening. Monday Night and early Tuesday, there is a greater chance (60+%) of widespread fog and freezing fog. The colder areas vulnerable to freezing fog and rime ice formation will mainly be north and west of a Meade to Dodge City to Larned line. Fog will likely be particularly dense over areas of deeper snow pack. The duration of freezing fog (probability of 1/2 mile or lower visibility 9 hours or greater at about 60-70%) will likely lead to riming on exposed surfaces and perhaps on some bridges and overpasses. During the day Tuesday, the MSLP/wind pattern will not change much, so the low level moisture will remain in place and with continued upslope component to the surface wind, any fog will be very slow to erode through midday, and it is quite possible 1/2 mile or less visibility may continue into the afternoon hours Tuesday. HREF shows 30-50% probability of 1/4 mile visibility at 21Z (3 PM CST) Tuesday across west central Kansas (mainly west of U283 and north of U50). On Tuesday, the next storm system will be advancing toward the southern High Plains with main impacts Tuesday Night into Wednesday, which will be discussed in the Long Term section. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 405 AM CST Mon Jan 22 2024 Tuesday and Tuesday Night, the main shortwave trough to affect southwest Kansas will be making its approach on the High Plains. This will not be a major event for our region, but there remains fairly high probabilities of a tenth to one-quarter inch of precipitation. Latest 00Z run of 100-member Super Ensemble continues to favor our southeast CWA (Red Hills region) with 90+ probs of a tenth of an inch, which tapers off to a 30-40% chance of one-tenth of an inch out near the Colorado border. The latest 00Z ECMWF deterministic run is showing a bit less precipitation than previous runs, and the ECMWF ensemble prediction system (EPS) reflects this as well as the probability of 1/4 inch precip for DDC fell to around 30% on this latest 00Z run vs. 45% on the previous 12Z run of the EPS. It is still a little too early to determine if this is the start of a downward trend in forecast amounts or if this latest 00Z run was an off run. The next challenge of precipitation type continues to be a fairly significant one, as temperatures will hover around 30-34F from north to south for much of the period during precipitation late Tuesday Night into midday Wednesday. The absence of low level cold advection along with the rather high ambient low level moisture (by January standards) already in place will likely favor more cold rain instead of freezing rain. That said, we will continue to carry a Rain/Freezing Rain mix forecast for the northwest 1/2 to 1/3rd of the DDC forecast area, particularly northwest of Liberal to Dodge City to Larned line. The grids will reflect up to 0.05" of ice accumulation across west central Kansas counties, but if temperatures warm above 32 degrees faster than currently forecast after sunrise Wednesday, then minimal or no impacts will result from this event. After Wednesday's storm system, yet another storm system in this larger scale pattern will advance on the south central CONUS Thursday Night into Friday, but the track of this late-week storm will favor areas to our south, so at this point, probabilities of precipitation will remain low (20-30 POPs mainly south of Dodge City to Stafford line). && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1108 AM CST Mon Jan 22 2024 South southeast winds at 10 knots or less can be expected over the next 24 hours. Given this persistent flow in the lower levels then the only real change in air mass will be an increase in low level moisture. As a result what improving visibilities and ceilings that may occur between 18z Monday and 00z Tuesday will give way to LIFR conditions by 06z Tuesday fog and stratus returns. Widespread fog will be likely (+80%) with a 60-70% chance for visibilities to be 1/2 mile or less after 06z Tuesday. Temperatures between 06z and 18z Tuesday will range from 30 to 35 degrees so periods of freezing fog may result in rime ice on developing on exposed surfaces. && .DDC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...Burgert