Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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195 FXUS63 KTOP 221921 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 221 PM CDT Sat Jun 22 2024 .KEY MESSAGES... - Isolated storms, some severe, are possible late this afternoon through early evening. Damaging wind gusts are the main hazard. - After a brief reprieve from the high humidity Sunday, heat indices from 105 to 110 are expected Monday and Tuesday afternoons respectively. - Cooler temps and late evening storm chances return midweek onward. && .DISCUSSION... Issued at 220 PM CDT Sat Jun 22 2024 Water vapor imagery this afternoon highlights the upper ridge anchored over the southern plains while weak southwesterly flow and an embedded shortwave trough push eastward through the northern plains. Current analysis shows the frontal boundary entering north central portions of the CWA while a mostly uncapped upstream environment has sfc CAPE values exceeding 3000 J/KG at the current hour. Limiting factors for more widespread storm development are the poor midlevel lapse rates and lack of strong convergence along the boundary. Nevertheless, CAMs are persistent in widely scattered convection developing in the 4-5 PM time frame, pushing southeast along the front through early evening. Steep low level lapse rates, effective shear values less 30 kts, and DCAPE approaching 1500 J/KG signals damaging wind gusts from collapsing storms being the primary hazard. There is a lower possibility for hail and would only be confined to cells that maintain a strong updraft. Winds weaken from the north tonight behind the front with a low possibility for valley fog to develop around sunrise. With the temp/dewpoint depressions around 3F and possibility for winds to stay up near 5 mph, confidence was not high for mention in the forecast. Sfc ridge axis crosses through the region Sunday, bringing slightly cooler and less humid conditions with highs in the low 90s in the afternoon. Unfortunately this is short lived as southerly sfc flow returns Monday, as the region wedges between the midlevel ridge to the south and the northern stream jet. Heat indices up to 110 are likely Monday, while Tuesday`s indices approach 107 potentially as dewpoints rise back into the lower 70s. Heat headlines are anticipated for early next week. Both ensembles from GFS/ECMWF are advertising an embedded shortwave trough making its way southeast Monday evening into Tuesday, bringing storm chances through the day Tuesday. This would remove the excessive heat concern, highly dependent upon the timing of the wave, looking to be closer to the Tuesday evening period. Upper ridge axis shifts to the east by Wednesday, causing more uncertainty in where overnight MCSs track - from Nebraska to possibly northern Kansas each evening through Saturday morning. A stronger, cold front may track through the region by Friday evening, providing much needed heat relief next weekend. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1207 PM CDT Sat Jun 22 2024 VFR at terminals with anticipated fropa occurring from 00Z to 02Z west to east. TSRA coverage still remains limited aft 22Z along the boundary, however given the consistency in guidance of development near KTOP/KFOE, opted to keep mention of VCTS thru 02Z. Patchy fog cannot be ruled out at KTOP/KMHK aft 10Z, with some uncertainty on wind speeds and low level moisture. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Prieto AVIATION...Prieto