Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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975 FXUS63 KTOP 140903 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 403 AM CDT Tue May 14 2024 .KEY MESSAGES... - Mostly dry weather is expected today, aside from a stray shower in far eastern KS this morning. - Shower and storm chances (50-80%) return Wednesday into Thursday. Confidence lowers for rain chances into the weekend. - Temperatures stay near average for the next few days, then warm up for the weekend. && .DISCUSSION... Issued at 402 AM CDT Tue May 14 2024 The 500mb low is situated over western MO early this morning, followed by weak ridging over the central Rockies and the next low- amplitude shortwave over the Intermountain West. Another area of low pressure aloft is noted off the coast of CA. At the surface, we are left in a narrow ridge axis between the low in MO and low pressure in the Dakotas and WY. A few deformation showers remain in far eastern KS on the north and west side of the low to our east, and an isolated shower may still clip our eastern counties this morning. The system should move far enough east after sunrise to bring rain showers to a complete end. Most of today is expected to be dry as we find ourselves between the two systems and the ridge passes through the area. Clouds may be a bit slow to move out in far eastern counties, though highs are still forecast in the 70s area-wide, near average for the middle of May. There are low chances (20-30%) for rain to move into central KS after midnight, but forecast soundings take time to saturate and the better ascent arrives toward Wednesday afternoon and especially evening as the shortwave energy ejects out from the upper trough. For this reason, the highest PoPs (50-80%) continue to be focused in the 00-12Z Thursday time frame. Deep-layer shear is forecast to be in the 30-40 kt range, which could support a few more organized storms if a stronger updraft can get going. "If" is the key word there - the best instability (CAPE of 1000-2000 J/kg) looks to be confined to a narrow corridor along the southwest edge of our forecast area, with instability dropping off as you go north and east. Am not sold on stronger storms developing in areas where only a few hundred J/kg of MUCAPE exists. The amount of instability that storms have to work with may depend on how far north a weak warm front can make it during the day Wednesday, so this will bear watching through the next 36 hours or so. Instability and shear both weaken into Thursday, not enough to eliminate chances for thunderstorms, but enough to lower the likelihood of severe weather. There are still some model differences in how the pattern evolves heading into the end of the week - some suggest the southern stream trough phasing into the northern stream by Friday, while others suggest the southern stream develops into a closed low over the area on Friday. The latter scenario has a greater chance of keeping some showers and thunderstorms around on Friday in eastern areas in particular, so lower-end PoPs remain in the forecast. Ensemble solutions diverge further through the weekend into early next week, so confidence in rain chances continuing through this time period is rather low. Saturday currently looks like the warmest day, as the NBM 25th percentile has forecast highs into the 80s for nearly the entire area with the higher end of the guidance pushing 90 for some locations. So it at least appears likely to see warmer temperatures on the horizon as we head into the weekend. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1245 AM CDT Tue May 14 2024 Satellite still shows low-level clouds over much of eastern KS, though some recent obs have showed cigs lifting to VFR. Have decided to resolve this with a tempo of MVFR cigs for the first few hours at TOP/FOE, as there could be some bouncing around before clouds scatter out completely. Have also seen BR/HZ reported at TAF sites as well as a few surrounding sites, so have utilized the tempo group for reduced vis associated with this in addition to the cigs. Otherwise, expect northerly winds for most of the period, increasing slightly to around 10 kt at TOP/FOE this afternoon. Light winds turn to the east/southeast later in the evening. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Picha AVIATION...Picha