Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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440 FXUS63 KTOP 171050 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 550 AM CDT Fri Jul 17 2026 .KEY MESSAGES... - There could be an isolated shower or storm this afternoon. - Confidence in a warming trend through the weekend and into Monday is good. Some locations could see triple digits for highs Monday. - A pattern shift by the middle of next week looks to bring about more normal temperatures and a chance for showers and storms. && .DISCUSSION... Issued at 149 AM CDT Fri Jul 17 2026 Water vapor imagery from 07Z showed an upper low over west TX with an upper ridge axis set up from the central Rockies to the upper MS river valley. This placed the forecast area under the influence of the ridging while the mean westerlies remained over the northern and Canadian plains. Surface obs showed a rather relaxed pattern with low pressure across the northern plains and high pressure across the lower MS river valley. The forecast for the next several days is expected to be influenced mainly by upper ridging with the model consensus showing the ridge building across the central high plains through Monday. So the synoptic pattern looks to favor a warming trend with limit chances for precip. This afternoon looks to be a period where isolated storms pop up. Forecast soundings across the region show an uncapped airmass with modest instability which could be enough for an airmass shower. But limited wind shear and no obvious dynamics within the upper ridge should keep any storm that forms of the pulse variety similar to what we had Thursday. Although CAMs don`t show nearly the coverage of showers and thunderstorms. The upper ridge strengthening for Saturday through Monday lower probabilities for precip. Cluster analysis of the 12Z ensembles shows there is not much difference from the models through Monday. And the GFS/ECMWF/Canadian ensembles show pretty reasonable spreads in temps of three to five degrees through Monday. This lends some confidence in the NBM temp forecast for Sunday and Monday. Unfortunately the spreads in dewpoint temps don`t remain as low and the NBM is showing dewpoints mixing out a little more by Monday. Still there is a signal for heat indices between 100 and 105 degrees in the afternoon Sunday and Monday. Some places may see air temps hit 100 degrees Monday. By the middle of next week, cluster analysis shows some differences in the amplitude of the ridge/trough pattern over North America and introduces more variability and spread in the forecast. However the general idea is for the upper ridge to begin shifting west and south by Tuesday. This should bring a better opportunity for perturbations within the pattern in impact the forecast area and also allow temps to trend closer to normal. Operational solutions are pointing towards Wednesday night and Thursday morning for some shortwave energy to move across the area and bring a chance for showers and storms. This is reflected in the NBM forecast pretty well. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 550 AM CDT Fri Jul 17 2026 Predictability of SHRA impacting the terminals remains on the low side, especially with the last couple runs of the HRRR backing off on convection. Still forecast soundings and other model guidance show a signal for isolated convection with the heat of the day. Will keep a VFR forecast and let the day shift evaluate TS potential this afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Wolters AVIATION...Wolters