Area Forecast Discussion
Issued by NWS Oklahoma City, OK

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FXUS64 KOUN 220016

Area Forecast Discussion
National Weather Service Norman OK
716 PM CDT Sun May 21 2017

Adjusted precipitation chances through evening and overnight in
northern Oklahoma.


Visible satellite loop this evening revealed steadily increasing
cumulus development across northern and northwestern portions of
Oklahoma. At the same time, an area of thunderstorms continues to
persist across the northern Panhandles. Through 7 PM, shower
activity has increased across southern Kansas, with some of these
showers developing south of the OK/KS border. This activity is
primarily being driven along an axis of 320 to 325K isentropic
ascent, assisted by a 500mb short wave trough digging out of the
Inter-mountain West. Expect much of this activity to diminish
after sunset, especially the more eastern activity, south of
Wichita and far northern central Oklahoma, Ponca City to Wakita,
etc. After midnight, as the low level jet increases and boundary
layer winds shift more out of the south and southeast, increasing
low level moisture, precipitation chances will increase across the
Panhandles and western Oklahoma through Sunrise.



.PREV DISCUSSION... /issued 614 PM CDT Sun May 21 2017/

Mainly VFR conditions to continue. Ceilings will lower during the
day Monday as storm system brings a chance of showers and a few
thunderstorms to the area. Some temporary MVFR conditions may
occur with the heavier storms during the aftn.

PREV DISCUSSION... /issued 345 PM CDT Sun May 21 2017/

The forecast challenge of the day is determining rain/storm
chances tonight through Tuesday.

Tonight, most areas will remain dry. Chances for light showers and
perhaps weak thunderstorms will slowly increase across northwestern
Oklahoma throughout the night. Additional isolated showers and
weak thunderstorms due to a slight increase in isentropic lift may
affect locations near and south of Red River after midnight. No
strong or severe storms are expected tonight due to limited
instability (MUCAPE generally below 500 J/kg). Increased cloud
cover across much of the area. Lows will be warmer compared to
last night.

Monday, rain chances will slowly increase west to east during the
day. Not all locations will get wet. Western Oklahoma has the
greatest chance for some rain. Rainfall amounts should be rather
light due to the lack of significant moisture. Cloud cover may
limit heating and should keep temperatures below average.

Overall, believe the severe potential remains low Monday and
Monday night due to the lack of significant instability and
moisture. The highest instability with MUCAPE 1000-2500 J/kg is
forecast to be over western north Texas and western Oklahoma as
well as points west, so these areas have a higher potential for a
few severe storms with hail (likely less than golf ball size) and
perhaps damaging wind gusts near 60 mph mainly during the late
afternoon and evening hours. Strong 0-6 km bulk shear 30-50 kt
would support a mixture of supercells/multicells. Instability
remains questionable as cloud cover/light rain may limit daytime
heating, especially north of the Red River. A complex of storms or
two may form over the Panhandles or west Texas during the late
afternoon/evening hours on Monday which could dive southeast and
clip parts of western north Texas Monday night. The latest SPC Day
2 Convective Outlook handles these situations well.

By Tuesday, cooler conditions are expected. Elevated weak showers
and thunderstorms may linger across the area, especially during
the morning hours. Cloud cover should keep temperatures well below
average for this time of year with many areas possibly not
reaching the 70 degree mark.

Tuesday night through Thursday night, dry and mostly clear weather
along with a warming trend are forecast.

Friday through next Sunday, a warm/hot humid airmass may evolve
across the southern Plains along for some potential for severe
thunderstorms/heavy rainfall. Most models have been depicting
rather high amounts of potential instability (MUCAPE 2000-5000
J/kg), high low level moisture (surface dewpoints in the 60s to
lower 70s), and sufficient shear (0-6 km bulk shear 30-50 kt) for
severe storms with heavy rain. However, capping may be rather
strong during this time frame which could limit storm
development. For now, kept low chances for storms across the area.
Have low confidence in severe storm and heavy rainfall potential
during this time frame.



Oklahoma City OK  54  72  56  68 /   0  40  40  30
Hobart OK         54  71  55  70 /  10  60  50  40
Wichita Falls TX  56  75  59  70 /  20  60  60  50
Gage OK           55  70  50  68 /  40  60  40  20
Ponca City OK     53  73  54  69 /  20  30  30  20
Durant OK         57  74  58  71 /  20  40  60  50




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