Area Forecast Discussion
Issued by NWS North Platte, NE
Issued by NWS North Platte, NE
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101 FXUS63 KLBF 172105 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 405 PM CDT Tue Sep 17 2024 .KEY MESSAGES... - Strong to severe thunderstorms are expected to move into western Nebraska Nebraska this evening with the primary threat being damaging wind gusts of up to 80 mph.. - Strong southerly winds gusting up to 50 mph across much of the region will continue to create elevated to near critical fire weather conditions into this evening,mainly west of Hwy 83. - Active weather looks to return this weekend into early next week as another trough within southwest flow aloft tracks across the area. At this time, precise details remain somewhat uncertain. && .SHORT TERM /THROUGH TONIGHT/... Issued at 248 PM CDT Tue Sep 17 2024 After nearly full sun into this afternoon, temperatures have reached well into the 90s with a well mixed boundary layer getting high momentum winds winds aloft to the surface with gusts of 35 to 45mph across central and western Nebraska. Given low humidity and dry fuels west of Hwy 83 there will be enhanced to near critical fire conditions into this evening. A cold front approaching from the west is triggering thunderstorms upstream over the higher terrain and this activity will eventually come off the terrain and move thorugh the panhandle and into the western sandhills early this evening. Dry air is keeping instability limited to the west though mechanical lift and modest lapse rates aloft will fuel initial development. However the dry boundary layer with steep low level lapse rates and widespread DCAPE values of 1400J/kg will aid downward momentum transfer and create robust thunderstorm outflows. There will be potential for significant winds in excess of 75mph as the thunderstorms move in early this evening west of west of Hwy 83, and especially out to Hwy 61. Greater instability to the east will start to wane with loss of daytime heating as the storms continue moving east to the Hwy 83 corridor later this evening, though strops will maintain potential for winds in excess of 60mph through Hwy 83 before diminishing as the continue further east through the overnight hours. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 248 PM CDT Tue Sep 17 2024 While moderate uncertainty continues through the extended period, the latest run of ensembles seems to be favoring the initial closed low over the northern Rockies moving northeastward into southern Canada through the end of the week, while the second closed low takes a more southerly track through southern CA and the Four Corners and moving across the Plains this weekend. The result will be high confidence in temperatures trending cooler with readings generally below normal this weekend and into the first part of next week, though confidence in precipitation is much lower. There is disagreement among ensemble members with varying degrees of run-to-run consistency as to how rapidly and how much the second low fills as it moves into the Plains, as well as exactly how far south the system will dig. This has direct implications for precipitation potential this weekend with potential for a tight north/south gradient between little precipitation north and significant precipitation south, and this is evident with dispersion increasing in QPF plumes through the weekend. Box and whisker plots also show the uncertainty with a range of about 0.40 inches in the 25th percentile to 1.39 inches in the 75th percentile at North Platte for 24 hour precipitation ending Sunday morning, and these numbers become 0.10 and 0.84 at Valentine. So after 2 dry days Wednesday and Thursday we will see a steadily increasing potential for precipitation through the weekend with the possibility for significant precipitation mainly limited to locations from Imperial through North Platte to O`Neill southward. Uncertainty continues into the first part of next week with potential for unsettled conditions in northwest flow aloft. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 1205 PM CDT Tue Sep 17 2024 Primary aviation concerns this period will be strong southerly winds ahead of an approaching cold front, followed by potential for severe storms this evening. Expect winds will be increasing through this afternoon before peaking at TAF sites just ahead of thunderstorm arrival, generally in the 35 to 40kt range. Given strength of gusts at the surface will omit LLWS from the TAFs as winds aloft are not much stronger. Will use a 02Z-04Z window for timing arrival of thunderstorms and potentially severe outflow winds with a quick swing of direction to the west. Will reevaluate timing and peak winds once radar trends become established. Will bring conditions to MVFR with passage of the thunderstorms though a brief period of IFR is possible, especially given potential for blowing dust to accompany arrival of outflow winds. Favorable flight conditions return by daybreak with VFR expected through the latter portion of the valid period. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...MBS LONG TERM...MBS AVIATION...MBS