Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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340 FXUS63 KGID 300601 AFDGID Area Forecast Discussion National Weather Service Hastings NE 101 AM CDT Thu May 30 2024 .KEY MESSAGES... - Thunderstorms will move into the area during the late evening-overnight hours with gusty winds and small hail possible. - Strong to marginally severe thunderstorms possible on Thursday the main concerns for large hail and damaging wind gusts. - Precipitation chances (50-70%) throughout the day on Thursday and decreasing throughout the day on Friday (20-50%). - Scattered precipitation chances this weekend (20-60%) and into next week, mainly during the late afternoon-overnight hours. && .DISCUSSION... Issued at 400 PM CDT Wed May 29 2024 This Evening and Overnight... A line of thunderstorms over the western High Plains will move east into the area late this evening-overnight, with precipitation chances for most areas arriving after midnight. Weak instability and shear will help to keep storms marginally severe at most as they enter the forecast area. Areas west of Hwy 283 are in the SPC day 1 risk for severe thunderstorms, with wind gusts to 60 mph and small hail possible. Storms are expected to weaken as they continue to move east across the area overnight. There is some uncertainty in how widespread this line of storms will be, with 12z HREF ensemble members in agreement that the line will become split as it propagates east. Thursday and Friday... Scattered showers and thunderstorms will be ongoing to start the day on Thursday. How widespread cloud coverage is from these storms will impact precipitation chances for the rest of the day. Areas that see sustained clearing will likely be able to destabilize sufficiently to break the "cap" and have scattered afternoon thunderstorms. Western portions of the area appear to have the best chances to see clearing, as the 12z HREF members indicate showers/storms may continue across eastern portions of the area late Thursday morning. A cold front will enter northwestern portions of the area Thursday afternoon which will provide an additional source of lift for thunderstorm development. Shear values of 25-30Kts combined with instability of 1000-2000 J/Kg will allow for a few strong to marginally severe thunderstorms to develop. The main severe weather concerns would be for large hail and damaging wind gusts. Severe weather concerns will decrease overnight as stability increases. Scattered showers and thunderstorms will continue overnight (25-70%). ECMWF and GFS ensembles indicate PWAT values will be around 150% of normal which could lead to locally heavy rainfall of 2-3 inches. Areas that receive multiple rounds of storms will have the highest chances to see localized flooding. Scattered to isolated showers and thunderstorms will come to an end during the day on Friday. Thunderstorms over the western high plains may impact western portions of the area late Friday evening, though there is uncertainty on how far east these storms make it. Highs on Friday will be in the 70s. This Weekend... A series of shortwave troughs will move through the area this weekend. While the GFS and ECMWF still differ some on the strength and timing of the troughs, it appears that thunderstorms are possible (30-60%) during the late afternoon-overnight hours each day. Moderate instability will be in place on Saturday, with storms developing off the lee of the Rockies. Storms that enter the area would have the potential to be severe. Highs on Saturday will be in the upper 70s to low 80s. Instability will be higher on Sunday as temperatures climb into the mid to upper 80s, along with higher dewpoints. Warmer air aloft on Sunday may inhibit thunderstorm development, however a cold front moving through the area may provide enough forcing for thunderstorms to develop. Thunderstorms that develop on Sunday would have the potential to be severe. Details on the timing, evolution and type of any severe weather chances this weekend will become clearer as the event gets closer. Next Week... Precipitation chances (15-45%) linger into next week, with the highest chances occurring during the late afternoon-overnight hours each day. A more impactful shortwave will move through on Tuesday, though there is still model disagreements on the timing and strength of this trough. Behind this shortwave a ridge will begin to build over the western United states. ECMWF and GFS ensembles disagree on the strength and placement of this ridge, however warmer and drier weather would move in towards the middle-end of next week. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1255 AM CDT Thu May 30 2024 Primarily VFR during the period, though non-zero chance for MVFR CIGs afternoon into overnight. Tricky forecast due to uncertainties regarding thunderstorm timing, coverage, and intensity. First this morning, cluster of weakening thunderstorms will push in from the W next few hrs. This activity is forecast to weaken beyond 09Z, but isolated pop-up thunderstorms will be possible to redevelop just about anytime through the remainder of the overnight, and even through much of the daytime hrs. Tried to back off the VCTS to VCSH during periods where chances are lowest. Conceptually speaking, would expect an increase in thunderstorm chances by late afternoon and into the evening, but very low confidence in details (timing/coverage) continue as forcing is nebulous. CIGs will fluctuate lower in and near convection, but should remain primarily VFR 4-8K ft. There are some indications for CU with MVFR worthy bases to develop this aftn, but coverage is uncertain. At least MVFR CIGs become increasingly probable (50-60%) beyond 00Z Friday, but will tackle this in later TAFs. Winds outside of convection should be primarily SErly 9-14kt with gusts near 20kt. Convection this morning should give at least a 2-3hr window for a wind shift to gusty W/SW winds, but think a turn back to SErly will occur by sunrise. This evening winds will gradually back to E then NE at 5-9kt. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Davis AVIATION...Thies