Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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653 FXUS63 KTOP 111120 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 620 AM CDT Tue Jun 11 2024 .KEY MESSAGES... -Temperatures trend upward through midweek with the hottest day expected to be Thursday when heat index values could approach advisory levels. -Strong to severe storms could also occur late Thursday along a surface front. -Slight chances (20-30%) for storms will remain in the forecast through the upcoming weekend. && .DISCUSSION... Issued at 356 AM CDT Tue Jun 11 2024 Early today, a mid-level trough axis is traversing the Upper Midwest. An associated weak surface boundary is moving through Nebraska. That front looks to stall north of the forecast area and wash out this afternoon. Thus, have adjusted POPs to remain less than 15 percent in northern sections of KS given weak lift along the dissipating boundary. The temperature trend continues an upward progression today with highs this afternoon about three to five degrees warmer than yesterday. The pressure gradient increases across the forecast area on Wednesday, resulting in stronger southwesterly winds. Continued WAA with the southerly flow will help boost temperatures into the low and mid 90s. Moisture will also continue to increase through midweek. Our next cold front will move into the area on Thursday. With strong southwesterly flow and pre-frontal compression, confidence continues to increase in near advisory level heat index values occurring Thursday afternoon. Highs could reach 100 degrees in central KS with the rest of the area reaching the mid 90s. Dew points are forecast to be in the upper 60s and low 70s as moisture pools ahead of the aforementioned boundary. That will result in heat index values between 100 and 105 degrees area-wide. A Heat Advisory may be necessary as we approach this timeframe. Additionally, strong to severe thunderstorms could develop along the front in northeastern KS Thursday afternoon and evening. The very hot and humid air mass will allow for abundant instability with ensemble models showing a 50-70% chance of at least 4,000 J/kg of MUCAPE. Shear will be present but more on the weak side, with models showing around 30 kts of effective bulk shear. Thus, the main concern with storms will be damaging wind gusts and hail. Deterministic models show Thursday`s front stalling across the forecast area on Friday. Additional storm development could occur if the front remains in the area, so did increase POPs slightly to account for this possibility. A mid-level trough then moves out of the southwestern CONUS and over the central High Plains on Saturday. Will keep some low end POPs in the forecast for portions of the weekend as that wave moves over. Confidence on timing is not high right now given differences in model evolution of the system. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 618 AM CDT Tue Jun 11 2024 VFR continues through the 12Z TAF period. Southwest winds will increase late morning to near 10 kts, and decrease again around sunset. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Teefey AVIATION...Teefey