Area Forecast Discussion
Issued by NWS Amarillo, TX

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060 FXUS64 KAMA 211651 AFDAMA Area Forecast Discussion National Weather Service Amarillo TX 1151 AM CDT Sat Sep 21 2024 ...New AVIATION... .KEY MESSAGES... Issued at 311 AM CDT Sat Sep 21 2024 - Thunderstorms are very likely today across the Texas and Oklahoma Panhandles. Some of the thunderstorms could be severe, with the primary hazards being large hail and damaging winds. A tornado or two are also possible this afternoon through early this evening. - The thunderstorms today through Sunday morning could also produce very heavy rainfall which could lead to flash flooding, especially from this evening through tonight across the central and southern Texas Panhandle. - A cold front will bring in much cooler temperatures on Sunday with highs in the 50s to 60s across the combined Panhandles. && .SHORT TERM ... (Today through Sunday night) Issued at 311 AM CDT Sat Sep 21 2024 An active weather day is in store for the Texas and Oklahoma Panhandles. Widespread showers and thunderstorms are very likely today through Sunday morning. Some of these thunderstorms have the potential to be severe, with the primary hazard being large hail and damaging winds, but a tornado or two cannot be ruled out. The more widespread threat will be heavy rainfall which could lead to flash flooding. Cooler temperatures are expected both today and tomorrow with a cold front passing over the region on Sunday. The well advertised H500 low pressure system currently is located across the far southern tip of Nevada and is slowly moving off to the east. Out ahead of the system, plentiful low to mid level moisture continues to stream in across the Southern High Plains and a shortwave trough is providing ample lift to generate showers for some areas this morning. With the amount of moisture in the low to mid levels, the light showers may continue the rest of the morning provided subtle lift remains over the region. Looking towards later this morning into the afternoon hours, PVA associated with the strong upper level low will make its way across the Southern Plains. This wave will be associated with strong H700 theta-e advection across eastern New Mexico into west Texas. Numerous thunderstorms and showers should develop across this area starting later this morning and should continue into Sunday morning. Initially discrete storms, potentially supercells, look to form across eastern New Mexico and quickly track northeast with the strong southwest to northeast oriented flow across the region. Skinny CAPE profiles are depicted by forecast soundings along with a lot of sfc-6km shear on the order of 50 to 60 kts. Given the above parameters, a few severe storms look possible even though temperatures are forecast to only be in the 70s to low 80s. The primary hazard looks to be large hail with the mid levels cooling combined with the high shear. However, a tornado or two is certainly possible, especially if discrete supercells can remain along a stalled front across the western TX Panhandle. The severe potential will need to be closely monitored throughout the day today as there are certainly quite a bit of caveats, but the overall set-up will support some severe storms early this afternoon through this evening. The more widespread hazard looks to be heavy rainfall associated with these storms. Forecast PWAT values around 1.5 inches across the entire area are above the climatological max for this time of year. The 21/00z HREF probabilities for 1 inch of rain per hour are on the order of 30 to 70 percent for some locations across the Panhandles. Rain rates upwards of 2 to potentially 3 inches per hour are not out of the question given the aforementioned skinny CAPE profiles and the anomalously high PWATs. Storms look to be fast movers, which may limit the overall flash flood threat, but multiple rounds of heavy rain could move over some locations which would lead to a flash flood threat. This is especially the case going into tonight into Sunday morning. Thunderstorms with high rain rates could train along the stalled boundary during the late evening into the night time hours. Current model guidance has the front located across the southern Texas Panhandle during this time frame with a LLJ setting up with wind speeds of 30 to 40 kts. With all that being said, a Flood Watch has been issued for most of the Texas Panhandle from this afternoon through Sunday morning. Cannot rule out additional areas in the southeast being added to the watch should the front move a bit further southeast than currently forecast. The H500 low pressure system will weaken and move northeast towards the Central Plains on Sunday. As this occurs, a cold front should propel southward across the Panhandles and should be through the entire area by the afternoon hours. The front should push any rain showers or thunderstorms to the south and the rain chances should end by late afternoon for the CWA. The front will push in the coolest air of the season thus far with H850 temperatures progged to drop down to the upper single digits Celsius. Highs on Sunday look to be in the 50s to the north with 60s to maybe low 70s south. With the widespread cloud cover and the cold air mass moving in, NBM temperatures perform very poorly in these scenarios. Have continued the trend of lowering highs on Sunday using other blended guidance while noting there is room to go cooler if some of the hi-res models turn out to be correct. Muscha && .LONG TERM ... (Monday through Friday) Issued at 311 AM CDT Sat Sep 21 2024 Cooler temperatures will continue into early next week but will gradually warm back up late in the work week back up into the low to mid 80s. After a brief break in the rain chances on Monday, rain chances return Tuesday and Wednesday across the Texas and Oklahoma Panhandles. Upper level troughing looks to remain in place across the Panhandles early next week. This will keep the cooler airmass in place over the region which will suppress highs mainly below 80 on Monday and Tuesday. A low pressure system is forecast to dig south across the Rockies towards the Southern High Plains on Tuesday into Wednesday. Model guidance deviates tremendously on the evolution of this low pressure system. In any case, this system will bring a return of precipitation chances to the forecast area starting early Tuesday morning and continuing through Wednesday. At this time, the latest ensemble guidance suggests the better rain chances may remain to the west and south of the Panhandles, but models have been all over the place with whether or not the low will close off and slow down or be progressive. This leads to high uncertainty in the forecast from Tuesday onward, but the overall trend looks to be increasing temperatures into the 80s and drier conditions towards the later half of next week. Muscha && .AVIATION...
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(18Z TAFS) Issued at 1127 AM CDT Sat Sep 21 2024 Less than favorable conditions for flying are anticipated, especially after 21Z. Intense thunderstorms are expected across much of the combined Panhandles mainly between 21Z and 06Z Sunday. These storms could produce severe hail, erratic winds, and torrential rainfall, maybe even a short lived tornado in the southwest TX Panhandle. The torrential rainfall may reduce visibility as low as LIFR at times. After 06Z, storms may remain with low CIGs still impacting conditions at the terminals. By 12Z winds may start to shift to the north around 20 kts with higher gusts possible through 18Z Sunday behind a front. 36
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&& .PRELIMINARY POINT TEMPS/POPS...
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Amarillo TX 58 65 46 75 / 90 30 10 0 Beaver OK 53 60 43 71 / 90 50 0 0 Boise City OK 48 56 40 73 / 90 20 0 0 Borger TX 59 66 45 77 / 90 40 10 0 Boys Ranch TX 56 65 44 77 / 90 20 0 0 Canyon TX 58 67 44 75 / 90 30 10 0 Clarendon TX 62 70 48 74 / 90 60 20 10 Dalhart TX 51 59 40 74 / 90 10 0 0 Guymon OK 50 58 39 73 / 90 40 0 0 Hereford TX 58 68 44 77 / 90 20 10 0 Lipscomb TX 58 64 45 72 / 90 40 10 0 Pampa TX 58 65 44 73 / 90 40 10 0 Shamrock TX 63 72 48 74 / 90 60 20 0 Wellington TX 65 74 50 75 / 80 70 30 10
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&& .AMA WATCHES/WARNINGS/ADVISORIES...
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TX...Flood Watch through Sunday morning for TXZ001>004-006>009- 011>014-016>019-317. OK...None.
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&& $$ SHORT TERM...05 LONG TERM....05 AVIATION...36