Area Forecast Discussion
Issued by NWS Amarillo, TX
Issued by NWS Amarillo, TX
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297 FXUS64 KAMA 281734 AFDAMA Area Forecast Discussion National Weather Service Amarillo TX 1234 PM CDT Tue May 28 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM ... (This evening through Wednesday night) Issued at 1232 PM CDT Tue May 28 2024 Multiple outflow boundaries are apparent via multiple means which resulted from last night`s MCS and this morning`s elevated convection. Much of the area is seeing either no clouds (western Panhandles) or partly cloudy skies, but there are pockets of mostly cloudy skies. Nonetheless, dew points are in the 50s to low 60s across much of the area with temperatures already climbing into the 80s as of 12 PM. The quality of low-level moisture may wane some as diurnal mixing occurs, but MLCAPE values between 1500-2500 J/kg should be achievable by mid to late afternoon. By then, the westward moving outflow should be over or just west of Amarillo as a dryline pushes east into the southwestern TX Panhandle, and the cap should be sufficiently eroded for thunderstorms to develop. Forecast wind profiles are favorable for the development of supercells (effective shear 40-50 kts, 180 degree turning of the winds from surface to 500mb). However, weak low-level shear is expected this afternoon which creates a straight hodograph, suggesting splitting supercells would be favored. Given the moderately unstable environment, steep lapse rates, and decent shear within the hail growth zone, hail up to Tennis Balls (2.50") will be possible. Given the steep lapse rates below mid-level moisture which increasingly becomes drier and warmer toward the surface, damaging winds will also be possible, with some wind gusts between 70-80 mph possible. The tornado threat is certainly mitigated by the previously mentioned weak low-level winds, but can`t rule out a tornado with any right-moving supercell that can latch onto a boundary. However, current thinking is that any right-moving supercell would move out of the CWA given its motion and the currently favored area of convective initiation (southwest TX Panhandle). A secondary round of strong to severe thunderstorms may begin in the late afternoon hours. A shortwave trough will approach the northwestern combined Panhandles, developing thunderstorms in southeastern Colorado. These thunderstorms may be discrete/semi- discrete initially but grow upscale once they move into the northwestern combined Panhandles. These storms should also strengthen owing to moving into greater instability. Here, very large hail and damaging winds may be the initial threat but as the storms grow upscale, damaging winds should become the primary threat with large hail just below it. Can`t rule out a 70-80 mph wind gust early on in the MCS`s life. The strong to severe thunderstorm threat should wane past around 9-10 PM, but can`t rule out an additional strong to severe thunderstorm before Midnight. Isolated areas of flash flooding may be possible in urban areas, or with any slow right-moving supercell, given the very moist environment. Vanden Bosch && .LONG TERM ... (Tomorrow through next Monday) Issued at 1232 PM CDT Tue May 28 2024 A temporary break in the activity going into the day on Wednesday for most areas as a small amplitude ridge moves over the Panhandles. Later Wednesday night, a disturbance moving over the central Rockies may provide a chance for some showers and thunderstorms, but this would favor the far northern combined Panhandles. Going into Thursday, our next chance for more widespread strong to severe thunderstorms return. Will have to watch observational trends closely, including cloud cover, LL moisture return, etc. Overall setup appears to have a dryline setting up near the TX/NM stateline with a good easterly sfc flow. Latest data indicate with this that the dryline to help initiate thunderstorm chances should first start in the western Panhandles before moving east throughout the afternoon hours. The environment at this time should support a high CAPE and relatively low shear environment, which would favor severe weather parameters being large hail and damaging winds as the primary threats. Boundary convergence may enhance low level winds for a tornado threat as well. With PWAT values nearing the 99th percentile, and not a strong of steering flow, training and/or back building thunderstorms with heavy rainfall rates may also cause localized flooding. We will also be watching a cold front moving south the second half of Thursday which can also be a local catalyst of lift for thunderstorm development as well. Thunderstorm chances continue Friday into the weekend as the main southern CONUS synoptic pattern remains in place. Exact timing and ingredients for how strong thunderstorm may get will be determined as we get closer with time as more data is available. Temperatures on Friday will be below average, but for the remainder of the forecast period, temperatures will be above average. Meccariello && .AVIATION... (18Z TAFS) Issued at 1217 PM CDT Tue May 28 2024 The main forecast issue for the next 24 hours will be the potential for thunderstorms at all TAF sites later this afternoon into this evening. These thunderstorms may produce large hail and strong downdrafts with erratic winds at the surface. Have attempted to time the storms based on latest forecasts, but better clarity should exist once storms develop. Amendments will likely be needed. Otherwise, MVFR ceilings are possible later tonight into early tomorrow morning. Vanden Bosch && .PRELIMINARY POINT TEMPS/POPS... Amarillo TX 58 78 61 85 / 50 30 50 40 Beaver OK 58 80 60 85 / 60 30 50 60 Boise City OK 54 79 58 85 / 70 40 40 50 Borger TX 60 84 63 88 / 50 30 50 50 Boys Ranch TX 58 84 62 91 / 50 40 50 40 Canyon TX 56 79 60 87 / 40 30 40 30 Clarendon TX 58 76 60 80 / 50 40 50 50 Dalhart TX 54 81 58 86 / 60 40 40 40 Guymon OK 56 80 59 85 / 70 30 50 50 Hereford TX 57 82 61 91 / 40 30 40 30 Lipscomb TX 59 79 62 82 / 60 40 50 60 Pampa TX 58 78 61 82 / 50 30 50 50 Shamrock TX 59 79 61 80 / 50 40 50 60 Wellington TX 60 79 62 80 / 50 40 50 60 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...None. OK...None. && $$ SHORT TERM...52 LONG TERM....29 AVIATION...52