Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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811 FXUS63 KTOP 271046 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 546 AM CDT Thu Jun 27 2024 .KEY MESSAGES... - Thunderstorms tonight may pose a wind risk as they move in from the west. - Chances for severe storms look to be higher Friday afternoon and evening with supercells presenting an hail, wind and heavy rain risk. - Hot and humid conditions Friday are forecast to make it feel like it is between 103 and 109 degrees Friday afternoon. && .DISCUSSION... Issued at 237 AM CDT Thu Jun 27 2024 An upper ridge was centered over northern Mexico per the 07Z water vapor with an upper low over the Pacific Northwest and shortwave energy lifting into the northern Rockies. At the surface, weak ridging over the upper Midwest had nosed into northeast KS. This had displaced the deeper moisture south along the Red River valley and Gulf Coast. The main change to the forecast today was to delay POPs for eastern portions of the forecast area until the late afternoon or evening. Models show the better moisture return developing through the high plains with some influence from the surface ridge hanging on over northeast KS. This keeps the deeper moisture axis to the west with model progs developing little if any instability over the forecast area and in fact show dewpoint temps mixing out a little. This should make it feel a little cooler, but increasing mid and high clouds from the west could limit insolation through the afternoon also keeping highs in the mid and upper 80s. For thunderstorm potential, think this should mainly be driven by what convection develops off the high plains. Forecast sounding show some mid level saturation with a weak vort max passing west to east. This may be enough for some isolated rain showers in the afternoon. But with the lack of instability, the severe risk is going to have to come from the storms developing to the west. A developing warm air advection pattern into north central KS could bring in some elevated instability that could sustain convection moving in from the west with mainly a damaging wind risk. Forecast soundings are not as aggressive with the elevated instability advecting into eastern KS and the risk for severe storms may be quite a bit lower as storms move from west to east tonight. For Friday, think there should be a pause in precip chances through mid day as subsidence from overnight storms works east. This is expected to allow for a very hot and humid airmass to develop by Friday evening as a shortwave trough propagates east over the northern plains and brings a weak boundary into northern KS Friday night. Wind fields are forecast to be better for organized convection and with MUCAPE between 4000 and 5000 J/kg. This could lead to a few supercell storms developing along the boundary with a damaging wind and hail risk. PWs are also forecast to be very high at over 2 inches. This should lead to the potential for torrential rainfall and localized flash flooding should storms train over a location. Forecast highs in the 90s combined with dewpoints in the lower and middle 70s looks to create heat indicies in the 103 to 109 range for a good portion of the forecast area. Models show little change in the pattern through the middle of next week with upper ridging remaining just south of the forecast area and the mean westerlies staying north. Some amplification in the ridge could bring hot temperatures back to the area to start off the work week. Another frontal boundary looks to slip south by Wednesday. With this potential focus, the forecast has higher chance POPs (40 to 50 percent) Tuesday night and Wednesday. Otherwise precip chances look to be driven more by mesoscale features on the fringes of a surface high that is forecast to nose into the central plains through the weekend. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 546 AM CDT Thu Jun 27 2024 Areas of fog, mainly in the valleys and low lying areas, should lift as the boundary layer begins to mix around 14Z. VFR conditions should persist into the evening. There are some signs for isolated elevated -SHRA this afternoon, but limit coverage will preclude mentioning in the forecast. Will amend is the SHRA look to be more widespread. Think the better chances for TS will be overnight as the low level jet increases along with WAA. Coverage may still be scattered so will only have a VCTS for the favored window. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Wolters AVIATION...Wolters