Area Forecast Discussion
Issued by NWS Amarillo, TX

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000
FXUS64 KAMA 231830
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
130 PM CDT Sun Jul 23 2017

.UPDATE...
Been watching some MCV feature spinning just SE of AMA all day.
Cloud cover has held temps down and this combined with some
subsidence has pretty kept a lid on convection thus far. Trough
that slid through the region was providing north winds, but this
feature is washing out as advertised by models and we are seeing
winds veering more easterly in last hour. Models agree the
boundary will morph into an east/west oriented boundary with
subtle low level convergence developing along the feature at SFC-H85.
H85-h7 theta-e still looks favorable and dewpoints have remained
high on either side of the boundary. Still a little CIN noted
across the area assoc w/ warm nose around H8 seen on morning
sounding, but this has been lessoning. CAMs showed cooling in that
layer, and this seems to be occurring. ML cape is around 1000
J/KG while SB cape is around 2000 J/KG. A short wave riding around
the east side of the high is apparent on WV and model analysis
across ERN CO and NRN KS. This feature will drop in from the
north and move across the area late this aftn and evening. So,
despite slow to develop CU fields, we still think we will see sct
storms form in the late aftn and evening. For the update a bit
earlier, lowered temps and did lower aftn POPs some, esp in the
north where timing of the disturbance may be a little before
better recovery can occur. That said still think we will
eventually see sct TSTMS as advertised. Some strong pulses could
produce small hail, very heavy rain and gusty winds.

&&

.AVIATION...
Similar to yesterday, sct TSTM impacts are main issue and outside
these VFR conditions should prevail. Highest coverage in storms
will occur in Cen and SRN TX Panhandle between 5 pm and midnight.
Timing beyond that is difficult to say given disorganized nature
of these storms.

&&

.PREV DISCUSSION... /Issued 450 AM CDT Sun Jul 23 2017/

AVIATION...12z TAFS...
Scattered showers and storms are expected to continue across the
Panhandles, mainly near KDHT and KGUY. Winds be variable between
10-15 kts throughout the TAF period. PROB30 group continues
starting at 21Z through about 02z. Storms that develop could bring
MVFR/IFR categories to the TAF sites. Storms will be slow moving
and will likely produce heavy rainfall. Gusty winds and small hail
will be possible with these storms as well.

Weber

PREV DISCUSSION... /Issued 301 AM CDT Sun Jul 23 2017/

DISCUSSION...
Overall theme of the forecast remains unchanged with precip
chances during the early and late portions of the forecast.

Shortwaves in the upper flow have prolonged convection throughout
the overnight hours across the Panhandles with the greatest
activity across the Oklahoma Panhandle. CAMs suggest this activity
will diminish as we approach sunrise, and we won`t see
redevelopment until this afternoon. While we will likely see a
lull in convective activity later on this morning, current
thought is that CAMs are not resolving the upper disturbances
well. This would result in a much sooner lull. Think the lull will
be more towards 15Z rather than 10Z-12Z. For this reason, have
retained low end POPs through the morning hours before increasing
after 18Z. Severe weather is not anticipated through the early
morning hours with heavy rain being the primary hazard.

As we move into the afternoon and overnight hours, we will see
the influence of more perturbations in the upper flow. This will
also be as instability climbs into the 1500 to 2000 J/kg range.
Deep layer shear remains low but DCAPE values are forecast to rise
into 2000 - 2500 J/kg. As a result, organized convection is not
anticipated but can`t rule out a storm producing severe level
downburst or a few quarter size hail stones. Storms will likely
carry well into the morning hours on Monday before we see a
decrease in coverage around midday. This will be short lived as
the next round of perturbations approach the Panhandles to spark
additional storms for Monday night. This will be the last round of
storms for the greater potions of the area as the upper ridge
repositions itself briefly over the Panhandles.

Tuesday may be our driest day of the week as the ridge moves
overhead, but there is some suggestions that we may still see a
few storms sneak into the far northwestern corner of the
Panhandles. The upper ridge retrogrades back to the west Wednesday
and this will bring a return of the wet pattern through the end of
the work week. Deep layer shear is expected to be low once again
to keep the risk of severe weather limited. Looking beyond into
the weekend, we could see slightly better deep layer shear (~25kt)
so sever weather would not be out of the question.

&&

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

&&

$$

88/88



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