Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 220930
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
430 AM CDT MON AUG 22 2016

.DISCUSSION...

Surface high pressure will shift east of the CEN MS River valley
today as low pressure develops in the cen Plains. This will lead to a
notable increase in srly flow today with breezy and warmer
conditions across the area. A vort max seen in WV imagery across AZ
will lift NE clipping the WRN/NW Panhandles. This will provide isold
tstms moving out of NM into the Panhandles in the late aftn and
evening. Believe moisture and instability will limit areas affected
to the far west and this seems to be what CAMs suggest (if they
generate storms at all) but this will have to be watched for
potential updates to extend pops further east for the evening.

Moisture will continue to increase on Tue as additional disturbances
carve out a more significant srn stream trough across the desert SW.
A 70+ kt upr jet will develop across the NW Panhandles as the trough
deepens. H85-H7 theta-e ridge (remnants of the tropical moisture
causing flooding in S TX) and position of the of jet and modest
diffluence aloft will favor the SE half of the CWA for ISOLD to SCT
TSTMS Tue aftn and evening (perhaps higher pops just south). We are
not currently outlooked, but dewpoints in the 60s, high cape and some
very modest deep layer shear may be enough to trigger a severe storm
or two.

Wednesday provides a very similar scenario to the last fropa which
produced decent rainfall in the area last week. An initial boundary
is forecast to reach NW zones by Wed morning before hanging up
somewhere across the CWA. The main/stronger surge, again lagging
behind, is forecast to move into nrn areas by late aftn, before
pushing through the area in the evening and overnight hours. Believe
best rain chances will again occur with the main fropa overnight.
Models are not in great agreement WRT how much dry air pushes across
the region in advance of the front due to some SW low level flow. An
upr jet entrance region in advance of the slow moving trough across
WRN NM will provide favorable dynamic setup with large scale lift as
the front slowly passes through the area. NAM indicated bulk 0-6 KM
shear values of 30-40 and 60s dewpoints which suggests potential for
severe storms Wed aftn and overnight. SPC has included the region in
a marginal risk area on the day 3 outlook. If timing of the front is
and moisture fields are favorable as forecast (one of the biggest
question marks for this event), we may end up in a slight risk area
at some point. Of course, timing will also impact how much heavy
rainfall potential we see with this event as well.

The forecast becomes even more uncertain beyond Wednesday as the
front stalls possibly just south of the area due to continued
troughing to the west. GFS and ECMWF both suggest the favorable
upper dynamics and overrunning will produce continued post frontal
clouds and precip across the region Thu and Fri with low pops even
continuing into the weekend as the upr system shears and weakens but
remains over the area. Stronger storms and heaviest rainfall will
likely be confined to areas along the front Thu, wherever that ends
up. The boundary is forecast to back up north of the area on Friday
as what is left of the main trough finally moves out of the Rockies
and into the Cen Plains. Superblend pops are in 40-50% range Thu and
Fri and tough to argue against this given model solns, but
significant changes are possible depending on how details of frontal
position, etc work out.

Temps will warm into the 90s in advance of the front Tue and Wed but
should drop to near 80 if not the 70s on Thu and Fri. Will warm back
up over the weekend as srly flow returns.

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                84  65  88  67  86 /  10  10  20  20  30
Beaver OK                  89  69  93  71  87 /   5  10  20  20  30
Boise City OK              84  63  90  63  82 /  20  20  10  20  30
Borger TX                  88  69  92  70  88 /  10  10  20  20  30
Boys Ranch TX              88  66  92  66  87 /  20  20  20  20  30
Canyon TX                  86  65  89  67  86 /  10  10  20  20  30
Clarendon TX               85  67  89  69  88 /  10  20  20  30  30
Dalhart TX                 86  64  92  64  85 /  20  20  10  20  30
Guymon OK                  89  67  93  68  85 /  10  20  10  10  30
Hereford TX                86  65  89  65  86 /  20  20  20  20  30
Lipscomb TX                88  69  92  71  88 /   5  10  20  20  30
Pampa TX                   86  67  90  69  86 /  10  10  20  20  30
Shamrock TX                86  69  90  71  90 /  10  20  30  30  30
Wellington TX              87  70  90  71  92 /  10  20  30  30  30

&&

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

&&

$$

MJG



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