Area Forecast Discussion
Issued by NWS North Platte, NE
Issued by NWS North Platte, NE
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939 FXUS63 KLBF 111947 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 247 PM CDT Sat May 11 2024 .KEY MESSAGES... - Daily high temperatures remain near seasonal to above seasonal through the work week. Overnight lows mostly in the 40s, limiting any frost concerns this week. - Widespread chances of showers and thunderstorms tomorrow afternoon, with little to no severe weather expected. - The best chance for showers and thunderstorms comes Tuesday night into Wednesday morning, with some question on the potential for severe storms. Slight chances (less than 30 percent) of showers persist most days of the week. && .SYNOPSIS... Issued at 245 PM CDT Sat May 11 2024 Upper air analysis and satellite imagery place an upper level cut off low over northern Arizona. Further west, another wave is noted across the northern Pacific Ocean, with a ridge off the West Coast and a trough behind it. At the surface, high pressure is the dominant feature over the Plains. The major weather story has been the recent space weather activity, with the aurora visible last night and an ongoing G4 geomagnetic storm this morning and early afternoon. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 245 PM CDT Sat May 11 2024 Tonight, as the upper level low slowly tracks east, areas of showers and potentially thunderstorms are possible across portions of southwest Nebraska. The most likely area for rain tonight is along and south of a line from roughly Oshkosk to Broken Bow. Given the very limited forcing, no severe weather is expected with thunderstorms this evening. The other big weather story this evening remains the active space weather that caused aurora sightings across Nebraska and a fain amount of the United States last night. The ongoing solar activity has been quite intense, with possible impacts on radio and GPS. The Space Weather Prediction Center has extended their warning for Geomagnetic K-Index of 7 or greater, which may create an additional chance to see the aurora across western and north central Nebraska tonight. However, the biggest challenge will be sky cover this evening. Clouds are expected to move in this evening, with possible precipitation, again along a line from Oshkosh to Broken Bow. Areas to the north may be a bit more lucky with sky conditions, but will merit keeping an eye on for those hoping to get another chance at the aurora. The latest space weather information and aurora forecast can be found at swpc.noaa.gov. Chances of showers and thunderstorms continue on Sunday through Monday morning, as the upper level low is closer in proximity to the south and a cold front sweeps down from the north. Though thunderstorms are expected, the severe potential is low at this time, with marginal amounts of CAPE and fairly weak shear values. Current CAM guidance keeps storms tomorrow afternoon rather spotty in nature, keeping expected rain totals fairly limited, generally under one quarter of an inch. However, showers and storms may produce some locally heavier amounts, with expected PWAT values ranging from one half inch to one inch. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 245 PM CDT Sat May 11 2024 The upper air pattern remains fairly progressive over the course of the week. By Monday afternoon, the upper level low is expected to be over eastern Kansas, with nearly zonal flow aloft over wester and north central Nebraska. The nearby upper level low may still provide enough forcing for some light showers, mainly across southwest Nebraska and the Sandhills, however, guidance remains fairly spotty on this. Ensembles are a bit more optimistic for precipitation greater than or equal to one one-hundredth of an inch (around 90 percent chances across), but limited to the southern portion of the state for one tenth of an inch or greater. By Tuesday, the upper level pattern supports the best chance of showers and thunderstorms next week. An upper level shortwave begins to deepen across Wyoming. A surface system tracking through the region late Tuesday afternoon into the early morning hours of Wednesday will be the focus for showers and thunderstorms. For now, the severe weather threat is still a bit in question, but given the support and forecast soundings, will definitely be worth keeping an eye on. Though there is still some variance in the individual models, there has been some consensus in a narrow tongue of CAPE nearly along Highway 83, with just enough shear support to support severe convection. However, there still is some question model to model in how much CAPE and shear will be available. After the shortwave trough lifts to the north, the upper level pattern remains mostly to the north and south of the region. There is still a little uncertainty in the actual track of the upper level flow, and ensembles pick up on that uncertainty. Ensembles highlight that chances of measurable precipitation for the rest of the week remain generally in the 20 to 30 percent range. With the upper level pattern remaining fairly progressive, daily highs should remain nearly seasonal to above seasonal throughout the week. For reference, seasonal daily highs are in the low 70s across the region. As for overnight temperatures, generally expected temperatures will be in the 40s throughout the week, which will limit the chances for frost across the region. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1215 PM CDT Sat May 11 2024 Sfc low pressure across Manitoba will move east and be located across nrn Ontario by 12z Sunday. Meanwhile, an upper level disturbance across the srn Rockies this afternoon will move very slowly east and be located across the Colo Plains by 12z Sunday morning also. This system has the potential to produce isolated showers and thunderstorms along and south of I-80 tonight which become scattered in the same area by 18z Sunday. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Richie SHORT TERM...Richie LONG TERM...Richie AVIATION...CDC