Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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744 FXUS63 KTOP 201032 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 532 AM CDT Fri Sep 20 2024 .KEY MESSAGES... - Marginal risk (level 1 out of 5) possible overnight Friday due to possible nocturnal storms forming along the nose of the LLJ. Wind and hail may be possible with the most intense storms that do form. - Most every location across the area should see a very good chance of seeing meaningful rainfall through Saturday and Sunday night periods. North of I-70 still looking to see some of the higher amounts of around 2 inches or possibly greater in some spots. - Back to an early fall pattern returning to a generally dry conditions with temperatures in the 70s for highs and 50s for the lows into next week. && .DISCUSSION... Issued at 333 AM CDT Fri Sep 20 2024 The evolution of the upper air pattern continues to remain on track for a wet weekend ahead - which is more than welcome by most standards due to the dry conditions in place. The upper low over the northern Plains has lifted into south central Canada leaving the weak front over eastern Kansas left to stall out. This boundary will begin to return north as a warm front through the day today (Friday) as the next upper low over southern California begins to lift into the central Rockies and eventually through the central Plains. The southern Plains ridge is flattening and the ridge axis is shifting to the southeast. Today should be one of the last warm days before temperatures begin to head to a more fall-like and near-normal pattern for next week. Clouds begin to build late day into this evening as the southwestern CONUS upper low begins lifting northeast. A lead shortwave is forecast to emerge from the central Rockies into the overnight period Friday. A moderately strong LLJ also becomes active with the nose and convergence zone generally into north central and northeastern Kansas before veering overnight. With the warm moist advection resulting, a few storms could form which may pose a wind and hail risk overnight. Then, heading into Saturday - especially by Saturday evening into Sunday - the parent upper low more fully arrives on the scene. There remains generally good agreement amongst guidance that a modified surface ridge from the north will be sliding into the central Plains as this storm system builds with increasing DCVA into northern and northeastern Kansas areas. Deep saturated profiles with PWATs nearing 2 inches along with strong midlevel frontogenetical responses and convergent moisture transport should come together to provide a good chance for nearly all spots across the area to see meaningful precipitation over a 24-36 hr period. Still focusing on some of the heavier amounts generally along and north of I-70 with up to 2 inches and locally higher amounts possible. All other areas could see at least an inch of much needed rainfall. Flash flooding concerns remain low for now due to the nature of the event duration and very dry antecedent conditions in place with rivers and creeks being low. Into next week, after this system fully exits the area into Monday, expect much cooler conditions to help conditions feel more fall- like. Right now, a northwest flow pattern looks to keep the area void of any major storm systems and thus have kept a drying trend in place for the balance of the forecast period generally from Monday through the work week. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 520 AM CDT Fri Sep 20 2024 Keeping VFR conditions for now. There are some indications there may be ground fog around sunrise this morning mainly at KTOP as low level dewpoint depressions are minimal but the wind may be just strong enough to prevent MIFG from forming. Too much uncertainty for the last 6hrs of the period where it may be possible that isolated to scattered showers and storms could form so have opted to hint at saturated mid levels with BKN100. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Drake AVIATION...Drake