Area Forecast Discussion
Issued by NWS Amarillo, TX

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000
FXUS64 KAMA 230926
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
426 AM CDT Sat Sep 23 2017

.DISCUSSION...
Closed upper low over the Great Basin region to move east and then
northeast into the central and northern Rockies by Monday before
weakening into an open wave. Abundant mid and high level tropical
moisture to lift northward out of Mexico into the Panhandles by
tonight through early next week. Upslope surface flow will advect
low level Gulf moisture into the forecast area today through the
weekend before a cold front moves through the Panhandles Sunday
night and early Monday. Convection chances will be on the increase
today through much of next week, however the best chances will be
mainly after 21Z today and 00Z Sunday through Sunday and into
early next week. Initially, some of the convection this afternoon
and this evening may become strong to marginally severe with wind
being the main threat but hail up to quarter size could also
accompany the strongest convection. Heavy to very heavy rainfall
which could result in flooding or flash flooding remains the
greatest threat from convection later today and tonight through
Sunday and possibly Monday.

Another closed upper low is forecast to develop over the Great
Basin region by the middle of next week which should dig south
into the southwestern states and Four Corners region during the
latter half of next week. An upper ridge is forecast to build in
over the Panhandles ahead of this closed upper low late next week
which should allow for drier conditions. Cool surface high will
remain over the forecast area behind the cold front through most
of next week allowing for normal or slightly below normal
conditions across the Panhandles.

Schneider

&&

.HYDROLOGY...
Most of the short term hi-res models indicating convection with
very heavy rainfall primarily affect the western portions of the
Panhandles after 00Z Sunday. The RAP and the hi-res ARW are the
earliest with the heaviest rainfall between 21Z today and 00Z
Sunday. Otherwise, the HRRR, NAM and hi-res NMM holding off the
heaviest rainfall until after 00Z Sunday. All of the short term
models are in good agreement that heavy to very heavy rainfall
from slow moving convection could likely result in flooding or
flash flooding tonight into Sunday. Forecast model soundings
continue to indicate PWAT values of 1.25 to around 1.50 to 1.60
inches between 00Z Sunday and 00Z Tuesday which would put it in
excess of the 90th percentile for the forecast area for this time
of year. Confidence continues to increase for the threat of very
heavy rainfall resulting in flooding or flash flooding, therefore
decided to issue a Flash Flood Watch for the far western
Panhandles from 00Z Sunday until 18Z Sunday. Of course, this will
need to be adjusted in area and time depending on a faster or
slower onset of the heaviest rainfall from convection and also as
the convection progresses eastward tonight and Sunday. Rivers
will need to be closely monitored for rapid rises where gauges are
located.

Schneider

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                80  63  76  59  68 /  30  70  70  60  70
Beaver OK                  86  69  80  61  68 /  20  40  70  70  80
Boise City OK              75  59  77  52  61 /  80  90  50  50  50
Borger TX                  84  66  79  61  68 /  30  60  70  70  70
Boys Ranch TX              81  63  79  59  68 /  50  80  70  50  60
Canyon TX                  79  63  77  60  70 /  30  70  70  60  70
Clarendon TX               83  66  76  62  70 /  20  30  70  70  80
Dalhart TX                 77  60  77  55  65 /  80  90  50  50  50
Guymon OK                  83  64  79  57  66 /  50  80  70  60  60
Hereford TX                78  62  77  60  70 /  50  80  60  40  60
Lipscomb TX                86  70  79  63  70 /  20  20  70  70  80
Pampa TX                   82  65  77  61  69 /  20  40  70  70  70
Shamrock TX                85  68  80  64  72 /  10  10  60  70  80
Wellington TX              87  69  82  65  74 /  10  10  50  70  80

&&

.AMA Watches/Warnings/Advisories...
TX...Flash Flood Watch from this evening through Sunday afternoon for
     the following zones: Dallam...Deaf Smith...Hartley...Oldham.

OK...Flash Flood Watch from this evening through Sunday afternoon for
     the following zones: Cimarron.


&&

$$

24/11



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