Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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209 FXUS63 KTOP 011136 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 636 AM CDT Mon Jul 1 2024 .KEY MESSAGES... - Heat returns over western zones today and along and southeast of a modified cold front working into the area on Tuesday. Heat advisories in effect. - Several storm and rain chances set up across the area this morning and increasing into Tuesday afternoon along the modified cold front. - Storm chances may linger off and on through the 4th of July week with repeated storm chances through at least Thursday with little change to the weather pattern across the area. && .DISCUSSION... Issued at 455 AM CDT Mon Jul 1 2024 Only gradual changes to the overall upper air pattern lead to an active week ahead for off and on rain and storm chances through through the 4th of July holiday. The main belt of the Westerlies remain positioned over the northern tier of the CONUS. An anticyclone is set up over the southern Plains region with subtropical moist plume returning into the central Rockies and working around the apex of the dome of high pressure. Surface high pressure has continued to exit the region with deeper moisture now returning into western Kansas areas setting the stage for heat to return to the area. Also, storm chances generally increase beginning this morning into Tuesday and tend to persist through the week. Showers have been spreading across the area this morning with a few embedded thunderstorms. These should remain non-severe as mid level lapse rates are around 6 C/km and thus lower overall MUCAPE is set up across the area. Shear is also best off to the southwest of the area where the LLJ is strongest. The weak isentropic ascent advecting across the area this morning should allow for showers to and embedded thunderstorms to remain through at least part of the morning hours. Have increased POPs to 60-70 percent to account for more scattered to widespread coverage. As these storms exit the area, insolation resumes today over western areas with increasing moisture in place. A heat advisory remains in effect this afternoon over portions of north central Kansas. The heat expands on Tuesday with consensus solutions not moving the modified cold front into the area from Nebraska until around midday. This should allow for H85 temps to rise into the mid to upper 20C range ahead of the boundary. Mixing heights deepen prior to the boundary working through the area, which should allow most areas south of the Hwy 36 corridor to meet or exceed heat advisory levels with heat index values as high as 108 degrees for at least part of the afternoon. A heat advisory has been issued for Tuesday as well. Regarding the overall severe weather threat, a few storms may be possible later tonight as a vort max works north of the area through Nebraska. A storm or two could still kick off along over northern portions of the area. The probability for this appears low overall. The best severe threat sets up Tuesday along the modified cold front as the heat increases and moisture transport magnitude increases bringing PWs up to around 2 inches, MUCAPES could reach 4000-5000 J/kg. Even though the better shear appears to be well behind the frontal boundary, marginal shear could still allow for development along the boundary. Mostly parallel flow favors stright-line hodographs and possibly splitting storm modes or more interactions which could allow for at least some flooding threat to set up. Hail could be a threat if storms can remain semi-discrete. Wind appears to be a primary hazard with inverted-v type forecast soundings and a mixed layer top around 5-6kft. Higher LCLs would appear to limit the potential for tornadoes but still not ruling the potential out. So all typical sever hazards will need to be watched for come Tuesday afternoon in the vicinity of the boundary. After this, some uncertainty exists on timing and intensity of repeated shortwaves streaming from west to east around the base of the upper trough which looks to remain set up across the central CONUS for much of the holiday week. Keep up-to-date with forecast changes and have safety and backup plans in place as needed. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 628 AM CDT Mon Jul 1 2024 Scattered SHRA and embedded TS continue to move ENE through the region. Cig/Vis could drop into IFR category briefly due to brief heavy rain. Showers and storms come to an end by mid to late morning. Expecting SCT skies by early to mid afternoon with gusty SE winds for the remainder of the period. A strong LLJ develops overhead tomorrow morning but still expecting sfc winds to remain strong enough the result in marginal WS conditions. Overnight storms more likely to remain well north of the terminals during the last half of the period. && .TOP WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for KSZ020-KSZ021-KSZ034-KSZ035. Heat Advisory from noon to 8 PM CDT Tuesday for KSZ021-KSZ022- KSZ023-KSZ024-KSZ026-KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039- KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059. && $$ DISCUSSION...Drake AVIATION...Drake