Area Forecast Discussion
Issued by NWS North Platte, NE
Issued by NWS North Platte, NE
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228 FXUS63 KLBF 050837 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 337 AM CDT Fri Jul 5 2024 .KEY MESSAGES... - Severe weather is possible early Saturday afternoon through early Saturday evening. The hazards are large hail, wind damage and locally heavy rainfall which could cause flooding in some areas. - Additional showers and thunderstorms are possible Sunday but the risk of severe weather is low. - There are little or no rain chances Monday through Thursday. && .SHORT TERM /THROUGH SATURDAY/... Issued at 330 AM CDT Fri Jul 5 2024 Satellite and radar show a weak UA disturbance across ern WY and wrn Nebraska this morning. The disturbance is the result of midlevel frontogenesis embedded in strong northwest flow. This disturbance will move southeast through swrn Nebraska this morning and early this afternoon producing light showers and isolated thunderstorms. POPs use the short term model blend plus the RAP, HRRR, NAM, GEMreg and HREF. They are limited to 30 percent and the reason for this is dry air below 700mb. Winds aloft at h500-300mb are very strong, 40- 60kts, and this will greatly limit vertical development given the PWAT less than an inch. Attention is drawn to the prospect of severe weather advertised by the models Saturday afternoon and into the evening. Winds aloft will be strong, 30-50kts at h500-300mb and moisture will be on the increase with PWAT increasing to 1.0-1.25 inches. Wind speeds at h700mb and below will be 20kts or less and the resultant hodograph is fairly straight suggesting storm splitting will occur. The weak low level winds also support low tornado potential. Per SPC outlook, it is less than 2 percent for this event. The 15 percent significant hail outlook by the SPC is probably warranted given the strong shear and cold air aloft, -12C at 500mb. PWAT of 1.50 inches or higher is more common with July hail storms but that`s for baseball size hail. The timeline is early afternoon through early evening. The trigger is an upper low across srn Alberta which will drop south into ND and steepen lapse rates across Nebraska. The focus is a warm front across srn Nebraska. It is in this area the WPC outlooked for a marginal excessive rainfall risk contingent on upscale growth which is possible Saturday night. The warm front will try and lift north and moisture transport will be on the increase. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Issued at 330 AM CDT Fri Jul 5 2024 The upper low across Alberta will move into ND Saturday and be followed by a second reinforcing disturbance Sunday. The result will be additional height falls across Nebraska and the models show a second and perhaps a third round of showers and thunderstorms which could last into Sunday evening. This rain activity will develop in a cool moist environment but remain post-frontal. A cold front will be moving through the srn Plains. After Sunday, northwest flow continues but drier air will move in aloft. There are no significant rain chances Monday through Thursday in the blended forecast solution. There are several reasons for this. Winds aloft will become weak, less than 20 kts at h500mb, warmer air will move in aloft and the low level focus will be north or south of Nebraska. Still the northwest flow aloft will carry disturbances south and provide upper level support. The GFS and ECM one such disturbance will pass through Nebraska Wednesday. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1220 AM CDT Fri Jul 5 2024 VFR conditions are expected to prevail across western and north central Nebraska through tonight. Scattered showers are possible for far southwest Nebraska terminals early this morning, before another round of widely scattered showers and thunderstorms are possible this afternoon area wide. Additionally, winds strengthen from the northwest this afternoon, with gusts of 15 to 20kts anticipated. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Brown