Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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153 FXUS63 KTOP 292328 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 628 PM CDT Tue Oct 29 2024 .KEY MESSAGES... - Wind gusts around 50 mph through Wednesday morning. - Thunderstorms are likely tomorrow (100%), some severe with damaging wind around 70 mph, hail up to the size of half dollars and a few tornadoes. - Widespread rain is likely (60-80%) Saturday through Tuesday of next week with several inches of accumulation. && .DISCUSSION... Issued at 201 PM CDT Tue Oct 29 2024 A deepening surface trough and tight pressure gradient, combined with a well-mixed boundary layer are leading to widespread wind gusts of 50-60 mph this afternoon. These wind gusts will continue through Wednesday morning as the boundary-layer is expected to be mixed through the night. Tomorrow, a deep upper-level and surface trough will move into Kansas. Forecast conditions have grown increasingly favorable for severe storms tomorrow afternoon and evening. The front is now forecast to move through a bit later in the day tomorrow, allowing for ample destabilization ahead of the front and an opportunity for the upper-level wave and low-level jet to coincide across eastern Kansas tomorrow evening. The 12 UTC suite of models now favor isolated, discrete cells developing in an environment characterized by ML CAPE of 1,500 J/KG, effective shear of 50-60 knots and SRH of 300-500 m2/s2. This favorable parameter space in combination with strong forcing via the cold front, upper-level wave and low-level jet could produce some higher end severe weather with wind gusts around 70 mph, a few tornadoes and hail around half dollar size. There are a few scenarios depicted in the forecast model data. One that appears to be growing more favorable is the formation of some isolated cells ahead of the cold front across portions of eastern Kansas (generally east of Manhattan an I-70 and south) tomorrow afternoon (1-2pm) and a line of storms developing along the cold front across central and north central Kansas. As the front progresses eastward through the afternoon and into the evening storms along the front are expected to strengthen as the upper-level wave moves overhead and combines with an impressive 50-60 knot low-level jet. Bowing segments and supercellular structures within the the line are likely given the strength of the shear and forcing. All threats would be possible in these features as with isolated cells that form ahead of the line. A few flies in the ointment so-to-speak could be cloud cover tomorrow afternoon and the shear orientation with respect to the cold front. Cloud cover could lead to slightly lower instability and shear vectors could lead to more upscale growth which would lead to more of a wind threat and less of a tornado or hail threat. We get a break Thursday and Friday as high pressure sits overhead. Numerous periods of showers and thunderstorms appear likely Saturday through Tuesday as a deep, slow-moving upper-level trough develops across the western CONUS and the central Plains remain in a favorable location to be impacted by waves exiting that trough. Ensembles indicate anywhere from two to as much as six inches of rainfall is possible through next week. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 628 PM CDT Tue Oct 29 2024 Gusty south winds continue through the period with gusts of 35-40kts expected. Confidence is increasing in MVFR stratus building in Wednesday morning although uncertainty remains in onset time and whether this stratus deck breaks up during the afternoon. There could be a few storms during the afternoon ahead of a cold front, but confidence in timing and location of these initial storms is too low to include in TAF. Storms are more likely as the front passes near the end or just beyond this TAF period. && .TOP WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 7 AM CDT Wednesday for KSZ008-KSZ009- KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026- KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055- KSZ056-KSZ058-KSZ059. && $$ DISCUSSION...Jones AVIATION...Flanagan