Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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280 FXUS63 KTOP 170809 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 309 AM CDT Mon Jun 17 2024 .KEY MESSAGES... - Hot and humid conditions both this afternoon and Tuesday afternoon, with heat indices in the mid 90s to near 102 degrees. - Thunderstorm chances in crease for the western and northern counties of the forecast area Tuesday afternoon through Wednesday night. - A few storms across north central KS may be strong to severe Tuesday afternoon and evening with damaging wind gusts and heavy rainfall as the primary hazards. && .DISCUSSION... Issued at 250 AM CDT Mon Jun 17 2024 Early this morning an upper trough has moved inland on the Pacific Northwest coast line. A broad upper ridge was located across the southeast US with a ridge axis extending west into the southern Plains. The 6Z surface analysis showed a lee surface trough across eastern CO, extending southward across eastern NM. A warm front extended from a low pressure center cross southwest NE, northeast across SD into central MN. Today through Tuesday: The Pacific northwest H5 trough will dig east-southeast across the Great Basin, then lift northeast across the central and northern high Plains. The stronger H5 jet max will remain across the central and northern high Plains and portions of northwest KS into NE and MN. This afternoon, the lee surface trough across eastern CO will deepen and the tightest surface pressure gradient will develop across western KS. Southerly winds across the western counties of the CWA will increase to 25 to 35 MPH with some gusts up to 40 to 45 MPH. It looks a bit marginal for a wind advisory issuance. The eastern half of the CWA will see winds increase by afternoon to 20 to 30 MPH range with some gusts of 35 to 40 MPH. The gusty winds will continue into the evening hours. Thunderstorms will develop across western KS ahead of a dryline that will mix east to the CO/KS border. These storms should diminish through the evening hours as they track northeast across west central KS into NE, remaining west of the CWA. High temperatures will reach the lower to mid 90s across the eastern half of the CWA with mid to upper 90s across the western half of the CWA. Heat indicies will range from the upper 90s to around 100 degrees. The far southwest counties may see heat indices reach near 103. Tuesday, low-level CAA across the northern Plains will cause a cold front to move southward across the central Plains during the day. The front will move southeast across northwest KS and approach north central KS by 00Z. There will probably be sufficient convergence for a line of showers and storms to develop ahead of the surface front. Most CAMs show a line of storms developing along the front during the afternoon hours across west central KS and south central NE. The effective shear across the CWA will be less than 20 KTS, but MLCAPES may reach 1500 to 2000 J/KG, so there could be some stronger to severe wind gusts in the line of storms across the northwest counties of the CWA during the late afternoon hours into the evening hours. Highs on Tuesday will reach the lower to mid 90s. Heat indices will run between 95 to 100 degrees. Tuesday night through Wednesdays night: A southern stream upper trough will develop across the southwestern US, as the lead H5 trough lifts northeast into the northern Great Lakes States. Several numerical models including the NAM, GFS and ECMWF show the surface front becoming stationary across the western and northern counties of the CWA before lifting northwest as a warm front late Wednesday night. There may be some marginally severe storms Tuesday evening across north central KS and portions of northeast KS but if storms train along and northwest of the front across north central and northeast KS, there may be some heavy rainfall Tuesday night into Wednesdays, resulting in some minor flooding. The total QPF show nearly 2 inches of rainfall across the northwest counties of the CWA Late Tuesday afternoon through Wednesday. QPF amounts drop off across east central KS with only 0.05" to 0.25" of QPF. If the front pushes a bit farther southeast before becoming stationary, then east central KS may receive more rainfall, but the 00Z model runs show that east central KS may remain dry. Highs along and northwest of the surface front on Wednesday will only reach the lower to mid 80s. The remainder of the CWA within the warm sector should see highs in the upper 80s to lower 90s. Thursday through Saturday: The southeast US H5 ridge axis will expand westward into the southern Plains, as the H5 trough across the the southwestern US retrogrades westward into AZ and southern CA. The surface warm front will lift northward into the northern Plains. Expect dry conditions with temperatures slowly warming into Saturday. Highs on Thursday and Friday will reach the upper 80s to lower 90s, and highs on Saturday will warm into the lower to mid 90s. Saturday night through Monday: The southwestern US H5 trough will lift northeast and phase with a northern stream trough across the northern and central Plains. The resulting low-level CAA will bring a weak front southward across the CWA Saturday night which will provide a chance for showers and thunderstorms across the region Saturday night into Sunday. The southern fringes of the H5 trough may also provide ascent as well. Frontolysis occurs Sunday night and southerly winds return. Expect only a slight cool down into the lower 90s for highs on Sunday. Look for highs to warm back into the mid to upper 90s on Sunday. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1229 AM CDT Mon Jun 17 2024 There may be some low-level wind shear early this morning as a southerly low-level jet around 1200 feet increases to 45 KTS. After 14Z the mixed boundary layer will increase deep enough to cause southerly surface winds to increase to 14 to 18 KTS with gusts of 24 to 30 KTS through the late morning and afternoon hours, and the stronger winds may continue into the evening hours. && .CLIMATE... Issued at 248 PM CDT Sun Jun 16 2024 Record Warm Low Temperatures June 17 Record Forecast Concordia 75 (2018) 77 Topeka 78 (1918) 75 June 18 Record Forecast Concordia 80 (1953) 75 Topeka 81 (2021) 78 && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Gargan AVIATION...Gargan CLIMATE...Flanagan