The same data is available at this site. Please update your bookmarks.
Thank you, and we apologize for the inconvenience.
Please send an email to SR-SRH.Webmaster@noaa.gov with any concerns.
848 FXUS63 KTOP 021139 AFDTOP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 639 AM CDT Tue Sep 2 2014 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 312 AM CDT TUE SEP 2 2014 Analysis at 08Z depicts the upper trough axis rotating through Iowa and Minnesota. Meanwhile the stationary front was positioned from southwest to northeast over eastern KS. Scattered thunderstorms have been ongoing for the past several hours as a result of this boundary. Convection is expected to track south and east away from the CWA this morning. Clearing skies along and north of the boundary where dewpoints reside in the upper 60s and low 70s may develop patchy fog through sunrise. Scattered mid level clouds and surface winds remaining slightly mixed in some locations should prohibit widespread development. Areas south of Interstate 70 see the best chance for patchy fog to form and lift shortly after sunrise. Light winds and mostly sunny skies reside for much of the afternoon with highs in the middle to upper 80s. Focus turns to thunderstorm chances beginning late this afternoon as the aforementioned stationary front lifts northward as a warm front through east central KS. Moisture pools along and north of the boundary with dewpoints progged near 70 degrees. MLCAPE gradient tightens after 21Z with latest guidance averaging near 3000 J/KG. Main question for this afternoon is the strength of the capping inversion. Contrary to the guidance consensus, the past runs of the NAM show a much weaker cap near the boundary, initiating thunderstorms mainly along and south of I 70 between 21Z and 03Z. Confidence is marginal on storms developing during the late afternoon with increased chances this evening as the veering LLJ transports deeper moisture into the area. The stronger updrafts will be capable of large hail and isolated strong wind gusts through early evening. Expect activity to weaken as it tracks towards western Missouri by Wednesday morning. Cloud cover within the warm sector tonight should limit lows to the upper 60s. .LONG TERM...(Wednesday through Monday) Issued at 312 AM CDT TUE SEP 2 2014 Forecast highlights in the long term include hot temperatures and heat index on Wednesday and perhaps into Thursday, timing of a front and associated precipitation chances late Thursday into the weekend, and a significant cool down behind the front. Any remnant thunderstorms should be quick to move east of the area on Wednesday morning. Warm advection through the night and into the day on Wednesday, along with deep boundary layer mixing, ample sunshine, and gusty south winds all point to a hot day on Wednesday. Temperatures are likely to rise well into the 90s, and while the mixing will be deep the airmass above the mixed layer will be quite moist and dewpoints may remain in the upper 60s to lower 70s through the day. This will result in the heat index ranging from 100 to 105 with some potential to climb into the 105-110 range depending on the eventual dewpoints. A building cap through the day will prevent any thunderstorm activity through Thursday morning. Thursday morning lows will be very warm in the 70s, setting the stage for another hot day. A cold front will approach the area from the northwest by late in the day on Thursday as a strong trough moves through North Dakota. Current model timing suggests the front will enter the forecast area by mid afternoon on Thursday with a thermal ridge immediately in advance of the front and another well-mixed boundary layer. Thursday should at least have somewhat drier air available to mix down to the surface so while temperatures may be a bit warmer, the dewpoints should be a bit lower. The end result will be a heat index in the 98-105 range although it seems that Thursday has some potential to be hotter than the current forecast depending on frontal timing. The strongest instability and forcing is expected to be northeast of the area over Iowa where dewpoints will be higher on Thursday, but convergence along the front should be sufficient for at least a chance of thunderstorms by late afternoon into the evening in northern Kansas. Wind shear will be very weak but with the hot conditions could see a localized damaging wind threat materialize. As the low level jet intensifies a bit through the evening, may see increased thunderstorm coverage despite the LLJ being largely parallel to the front. Some model guidance is quite aggressive in producing widespread precip, but with the parallel LLJ and a lack of strong forcing aloft have trended POPs a bit lower through Friday morning...although still a fair chance. The front will hang up over central/southern KS on Friday with faster westerly flow moving overhead along with embedded weak short wave troughs. This points to periodic chances for thunderstorms into Friday night, with chances decreasing during the day on Saturday as the front continues to push farther south. Then have a dry forecast for Saturday night into Sunday before troughing builds into the western CONUS and return flow brings a moisture surge back north with renewed thunderstorm chances for Monday. Post-frontal temperatures Friday through Sunday will be much cooler, with highs likely only in the 70s and lows into the 50s. The main uncertainty in eventual temperatures will be the density of cloud cover, but can say with confidence that it will be well below normal this weekend. && .AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning) Issued at 630 AM CDT TUE SEP 2 2014 Dense fog at KTOP/KFOE is expected to quickly lift shortly after sunrise from LIFR to VFR by 14Z. VFR conditions prevail as a warm front shifts winds to the east and southeast at or below 10 kts. Thunderstorms in the area are possible aft 06Z...however exact timing and location are uncertain at this time. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Bowen LONG TERM...Barjenbruch AVIATION...Bowen