Area Forecast Discussion
Issued by NWS Amarillo, TX

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000
FXUS64 KAMA 180931
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
431 AM CDT Thu May 18 2017

.DISCUSSION...
Latest 18/00Z hi-res model, numerical, and probabilistic guidance
are starting to come into more of an agreement for possible
showers and thunderstorms later this afternoon in the far eastern
Panhandles. The center of the main upper level low will move ESE
from Utah into southwestern Colorado as we go through the day.
Latest observations this morning indicate a surface low developing
centered over SE Colorado. With bands of positive vorticity
rounding the base of the upper level trough, this will help
establish localized lift and further establish a warm southerly
flow bringing warm dewpoint temperatures that will be well into
the 60s. The main question here is where exactly the dryline will
set up. ECMWF continues to be an outlier and have the dryline
setup furthest west, although has shifted further to the east
compared to the last model run. The remainder of the global and
hi-res models indicate a consensus of a dryline set up over the
far eastern Panhandles just about on the TX/OK stateline. With the
past handle of the previous event, will continue to favor the NAM
positioning of the dryline near the TX/OK state line along the
far eastern Panhandles. Latest 250 hPa upper level jet also
supports favorable upper level divergence over the northeastern
Panhandles going into the afternoon hours. Best chances of showers
and thunderstorms will be roughly a line from Beaver southward through
Lipscomb and southeastward toward Allison and Texola in closest
proximity to the main upper level features during the convection
initiation period along with perhaps being right along the
dryline. Along and out ahead of the aforementioned locations,
latest numerical guidance shows effective deep layer shear of
40-50 kts and MUCAPE of 2500-3500 J/Kg as we go into the
afternoon hours. This will support supercell development with
large hail being the main threat as these cells generate in a
healthy environment with large amount of CAPE in the hail growth
zone. As a LLJ kicks in of 40-50 kts out ahead of the dryline
later this afternoon, in-conjunction with a low level veering
vertical profile, isolated tornadoes cannot be completely ruled
out as this continues to be the trend from the previous model
runs. With the LLJ entering the region, these cells that generate
should quickly move out of the eastern Panhandles into western
Oklahoma and southern Kansas. The threat of showers and
thunderstorms for the eastern Panhandles should quickly diminish
after 00Z Friday.

As the dryline convection moves east out of our region, a Pacific
front will enter the region from the northwest as the main upper
level low continues to move east into eastern Colorado by Friday
afternoon. As the front slowly bisects the TX Panhandle, this will
help generate the best chances of some showers and storms across
the eastern and southeastern TX Panhandle. Latest guidance is
suggesting the dryline at this time will be well into western
Oklahoma as the main upper level low continues to move east which
will keep the chances of precipitation limited with the front
with limited moisture to work with. Eventually, the upper level
low will move northeast out of the central and southern Plains
with dry conditions returning for the weekend. High temperatures
behind the front will be below average for mid May.

As we go into early next week, a rather jagged upper level profile
with multiple northern and southern stream jets will bring a
series of disturbances across the region. Although still several
days out, our region appears to be under a persistent region
upstream of an upper level positive tilted trough with its axis
over the Mississippi River. As a result, best chances of
precipitation will for now be over northern areas through early
next week with temperatures continuing to be below average.

Meccariello

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                84  51  77  44  68 /  10  10  10  10  10
Beaver OK                  86  52  75  45  69 /  20  40  20  20  10
Boise City OK              76  44  68  40  65 /  10  10  20  20   5
Borger TX                  87  54  77  47  71 /  10  10  20  10  10
Boys Ranch TX              82  49  77  43  70 /   5  10  10  10   5
Canyon TX                  84  50  78  44  68 /   5  10  10  10  10
Clarendon TX               88  56  80  49  69 /  20  10  20  20  10
Dalhart TX                 79  45  72  41  68 /   5  10  10  10  10
Guymon OK                  82  49  74  43  68 /  10  10  20  10   5
Hereford TX                82  49  77  44  69 /   5  10  10  10   5
Lipscomb TX                86  54  77  47  70 /  50  40  30  20  10
Pampa TX                   84  52  76  44  67 /  10  10  20  20  10
Shamrock TX                88  57  80  51  69 /  30  20  30  30  10
Wellington TX              90  61  84  53  71 /  30  20  30  30  10

&&


.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.

&&

$$

15/29



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