Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 231750 AAC
AFDAMA

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
1250 PM CDT MON MAY 23 2016

.Mesoscale Update...
Early this afternoon, an upper-level low pressure system was in
place over southern Saskatchewan with a trough extending across the
Pacific Northwest. An upper-level ridge extends from South Texas to
the Great Lakes. Flow over the Panhandles will be generally weak as
the area will be between the northern and southern stream jet speed
maxima, with wind speeds aloft only peaking at around 40 kts through
250mb today. Meanwhile a surface low which has slipped into the
northern Panhandles overnight will slowly lift northeastward
throughout this afternoon. The dryline will stretch southward from
the low this afternoon, likely along a Claude-Pampa-Slapout line by
late afternoon. Dewpoints to the east of the dryline will hold steady
in the mid/upper 60s to low 70s, while dropping into the 30s and 40s
to its west. This will keep the best moisture and instability axis
focused along a corridor from the Low Rolling Plains of Texas through
western Oklahoma (clipping the southeastern TX Panhandle). Forecast
soundings indicate upwards of 3000-4000 J/kg of MLCAPE will develop
in that corridor, though some capping will remain. Thinking is that
any storm initiation today will be more closely tied to the dryline
where the cap is more likely to be broken. Storm motion will then be
to the east and northeast at around 20-30 kts, though clusters of
storms could develop by late evening as storms exit the Panhandles
and build southeastward into better moisture.

NF

&&

.Prev Discussion... /Issued 1224 PM CDT MON MAY 23 2016/

Aviation...
For the 18Z TAFS, VFR conditions are expected at all terminal
locations. Some mid to high level clouds could be possible throughout
the afternoon hours, but should diminish into the evening. Wind
speeds will also stay at or below 15 KTS, but will become stronger
Tuesday morning. KAMA could see some higher wind speed gusts Tomorrow
afternoon as well. KAMA and KGUY could see some low clouds...but have
left out mention in this TAF issuance. However, I have hinted at the
possibility of some low clouds or fog by lowering ceiling heights
overnight and early tomorrow morning.

Lorenzen

Prev Discussion... /Issued 645 AM CDT MON MAY 23 2016/

Aviation...
For the 12Z TAFS, expect low clouds and patchy fog to erode this
morning, leading to VFR conditions at all TAF sites by mid to late
morning. Low confidence as to whether or not tstms will impact any of
the terminal sites late this afternoon or evening, mainly at KGUY
and/or KAMA. Sfc dryline will likely move into central zones later
today to a position near or just east of a KGUY to KAMA line. Decided
to omit mention of tstms for this forecast issuance due to low
confidence in where the dryline ends up later today.

Andrade

Prev Discussion... /Issued 452 AM CDT MON MAY 23 2016/

Discussion...
Between the severe weather yesterday evening working over the
atmosphere and the outflow boundary left behind in the western
Panhandles, it is hard to say exactly what is going to happen today.
The dryline looks to set up somewhere in the western to central
Panhandles and will likely be the focus for storm initiation today as
an upper level shortwave provides the large scale lift. With 40 kts
of effective bulk shear flowing perpendicular to the dryline, plenty
of CAPE across the central and eastern Panhandles, and steep mid-
level lapse rates, storm mode should be discrete supercells. Forecast
soundings show the cap being broken around 3pm and a large amount of
CAPE in the hail growth zone. Main hazards today will be large hail,
up to baseballs, and damaging winds. An isolated tornado couldn`t be
ruled out either. With forecast PWAT values at 1.26, which is near
the climatological max for this time of year, heavy downpours will be
possible. If storms move slowly, flash flooding could be a problem,
especially in areas that received precip last night.

The dryline looks to push into the eastern Panhandles Tuesday, and
with another upper level shortwave bringing lift to the area, another
round of storms is expected. With similar values of bulk shear and
CAPE available, if the atmosphere isn`t too worked over after 3 days
worth of storms, Tuesday`s storms could be severe as well. As an
upper level trough digs into the western conus mid week, the area
will see a break from precip. Models disagree a bit in timing and
evolution of the trough as it slides east, so left the extended as a
model blend with slight chances for precip again on Thursday, Friday,
and Sunday.

Beat

&&

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

&&

$$

6/17



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