Flash Flood Warning 83, NWS Norman, OK

Area Forecast Discussion
National Weather Service Norman OK
135 AM CDT Fri Aug 11 2017

.DISCUSSION...
Primary forecast focus is on this morning's convection, along with
today and another complex tonight into Saturday.

This morning through sunrise, a loosely organized area of convection
will continue to move eastward across the northern half of Oklahoma.
A persistent MCV can be visualized on KVNX and surface observations,
in northwestern Oklahoma. The low level jet has continued to to
steadily increase ahead of this feature and convection will continue
to be supported by a fairly stout 500mb short wave moving eastward
off the western high plains of Colorado.

11/00z sounding from KOUN measured a pwat of 1.87 in, and KAMA, 1.36
in, both of which are above the 90th percentile. Nearest the MCV,
broad ascent coupled with MUCAPEs around 1000-1500 J/Kg, strong
updrafts will lead to efficient rain producing storms. In just over
an hour, Slapout, OK between, 10:15 pm and 11:15 pm, picked up 2.91
inches. This is concerning, leading to increased confidence that a
localized flash flooding threat will persist through the remainder
of the overnight hours into the morning. The heaviest rainfall from
Thursday occured over west central Oklahoma, from Kingfisher County
through Grady county. Most flash flood guidance would suggest, 2.50
to 3.00 in/hr for the lower threshold for Flash Flood Warning
issuance, if needed.

Felt it was necessary to issue a Flood Watch for flash flooding,
beginning this morning and continuing through Sunday morning. More
details to follow, but with several rounds of rainfall expected due
to overnight thunderstorm complexes, multi-day rainfall amounts of 3
to 5 inches are possible across much of central and western
Oklahoma, with locally higher amounts more than possible through
Sunday Morning.

Forward propagation vectors of around 20kts, suggest a fairly
progressive system, given similar 0-3km bulk shear values.
Therefore, concerns for backbuilding are not all that high.
Efficiency will be the primary driver for locally heavy rainfall.
Earlier, around 1030 pm, Slapout recorded a 58 mph gust. Given
instability over 1000 J/Kg and areas of 0-6km shear around 30 to 40
kts, instances of severe gusts, over 60 mph, and up to Half dollar
sized hail will remain a possibility overnight.

After sunrise, expect lingering showers and thunderstorms,
scattered, across portions of northern and central Oklahoma, with
the remaining complex continuing across eastern Oklahoma, possibly
nearer the KS/OK border. Expect any stronger storms to be well east
of the I-35 corridor. Precipitation chances will dwindle through the
late morning and through the afternoon, but with remnant outflow
boundaries and lingering instability, will keep low precip chances
for much of the region through the afternoon, with the best
potential for scattered development across central to south central
Oklahoma, near the Red River, where a surface boundary may stall
through late this afternoon.

As most are aware by now, we're stuck under a persistent pattern,
with a trend of nightly MCSs/complexes of some sort, near daily into
early next week. Convection will likely be ongoing over the high
terrain of Colorado/New Mexico and the Panhandles by late
afternoon/evening, this activity will persist moving steadily
eastward into the overnight. Looking at MCS maintenance parameters,
it's likely this activity will build east/southeast across western
Oklahoma into central Oklahoma through sunrise, Saturday. The wet
trend continues into Sunday, with another complex moving across the
region Saturday night into Sunday. As mentioned above, a Flood Watch
for flash flooding remains in effect through early Sunday morning.

Stay Safe!

Kurtz

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  85  70  81  70 /  60  40  70  70
Hobart OK         90  72  85  71 /  40  50  60  70
Wichita Falls TX  95  76  93  73 /  20  20  50  50
Gage OK           80  68  78  66 /  40  70  70  70
Ponca City OK     84  68  80  68 /  60  20  50  60
Durant OK         93  74  88  74 /  40  20  50  70

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch through Sunday morning for OKZ004>048-050>052.

TX...None.
&&

06/04

Hazardous Weather Outlook...UPDATED
National Weather Service Norman OK
1211 AM CDT Fri Aug 11 2017

OKZ004>048-050>052-TXZ083>090-120515-
Harper-Woods-Alfalfa-Grant-Kay-Ellis-Woodward-Major-Garfield-
Noble-Roger Mills-Dewey-Custer-Blaine-Kingfisher-Logan-Payne-
Beckham-Washita-Caddo-Canadian-Oklahoma-Lincoln-Grady-McClain-
Cleveland-Pottawatomie-Seminole-Hughes-Harmon-Greer-Kiowa-Jackson-
Tillman-Comanche-Stephens-Garvin-Murray-Pontotoc-Coal-Cotton-
Jefferson-Carter-Johnston-Atoka-Love-Marshall-Bryan-Hardeman-
Foard-Wilbarger-Wichita-Knox-Baylor-Archer-Clay-
1211 AM CDT Fri Aug 11 2017

This hazardous weather outlook is for portions of northern...
western...central...and southern Oklahoma...and western
north Texas.

.DAY ONE...Rest of Tonight...

.Thunderstorms...
Showers and thunderstorms will continue to develop and move across
portions of Oklahoma through early Friday. Some of the storms
could become strong to severe with strong wind gusts up to 65 mph
and hail up to the size of half dollars possible.

Heavy rain and flooding will also be possible in some areas
through Friday morning. Some locations could receive several
inches of rain in a short period of time.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday...

.Heavy Rain/Flooding...
Thunderstorms may produce heavy rainfall across the area
Friday through early next week. Several inches of rainfall may
occur across parts of Oklahoma which may result in flooding.

.Thunderstorms...
Thunderstorms will be possible each day. A few strong to severe
thunderstorms with damaging winds will be possible at times, but
widespread significant severe weather is not expected.

Get graphics and more details at weather.gov/norman...and follow
our weather forecast office on Twitter and Facebook.

BRB/11

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1139 PM CDT THU AUG 10 2017

OKZ009-110515-
Ellis OK-
1139 PM CDT THU AUG 10 2017

...SIGNIFICANT WEATHER ADVISORY FOR northwestern Ellis County Until
1215 AM CDT...

AT 1136 PM CDT, a strong thunderstorm was located 7 miles northwest
of Shattuck, moving east at 30 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 50 MPH...
Minor flooding in areas of poor drainage...

LAT...LON 3648 10000 3659 9972 3659 9966 3628 9961
      3626 10000
TIME...MOT...LOC 0436Z 260DEG 26KT 3636 9996

SIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1225 AM CDT FRI AUG 11 2017

OKZ014-110600-
Roger Mills OK-
1225 AM CDT FRI AUG 11 2017

...SIGNIFICANT WEATHER ADVISORY FOR southwestern Roger Mills County
Until 100 AM CDT...

AT 1223 AM CDT, a strong thunderstorm was located 8 miles south of
Cheyenne, moving east at 35 MPH.

HAZARDS INCLUDE...
Wind gusts over 50 MPH...

LAT...LON 3560 10000 3565 9956 3543 9967 3542 9999
      3542 10000
TIME...MOT...LOC 0523Z 273DEG 32KT 3550 9972

SIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1230 AM CDT FRI AUG 11 2017

OKZ009-010-015-110600-
Woodward OK-Dewey OK-Ellis OK-
1230 AM CDT FRI AUG 11 2017

...SIGNIFICANT WEATHER ADVISORY FOR Woodward...northwestern Dewey and
central Ellis Counties Until 100 AM CDT...

AT 1229 AM CDT, strong thunderstorms were located from Vici to near
Woodward, moving east at 35 MPH.

HAZARDS INCLUDE...
Wind gusts to 50 MPH...

LAT...LON 3661 9902 3622 9895 3620 9896 3598 9959
      3655 9980
TIME...MOT...LOC 0529Z 257DEG 31KT 3619 9933

SIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
103 AM CDT FRI AUG 11 2017

OKZ005-006-110630-
Alfalfa OK-Woods OK-
103 AM CDT FRI AUG 11 2017

...SIGNIFICANT WEATHER ADVISORY FOR northwestern Alfalfa and
northeastern Woods Counties Until 130 AM CDT...

AT 102 AM CDT, a strong thunderstorm was located near Capron, moving
east at 30 MPH.

HAZARDS INCLUDE...
Hail up to one-half inch diameter...
Wind gusts 40 to 50 MPH...

LAT...LON 3700 9827 3680 9836 3680 9876 3700 9875
TIME...MOT...LOC 0602Z 280DEG 27KT 3689 9855

SIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
118 AM CDT FRI AUG 11 2017

OKZ021-034-110645-
Beckham OK-Greer OK-
118 AM CDT FRI AUG 11 2017

...SIGNIFICANT WEATHER ADVISORY FOR southern Beckham and northwestern
Greer Counties Until 145 AM CDT...

AT 117 AM CDT, a strong thunderstorm was located 7 miles south of
Erick, moving east at 30 MPH.

HAZARDS INCLUDE...
Wind gusts to 50 MPH...

LAT...LON 3520 10000 3526 9999 3520 9940 3492 9945
      3507 10000
TIME...MOT...LOC 0617Z 280DEG 27KT 3511 9983

SIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
131 AM CDT FRI AUG 11 2017

OKZ006-007-110700-
Alfalfa OK-Grant OK-
131 AM CDT FRI AUG 11 2017

...SIGNIFICANT WEATHER ADVISORY FOR northern Alfalfa and northwestern
Grant Counties Until 200 AM CDT...

AT 128 AM CDT, a strong thunderstorm was located 5 miles northeast of
Cherokee, moving east at 40 MPH.

HAZARDS INCLUDE...
Wind gusts to 50 MPH...
Some flooding in areas of poor drainage...

LAT...LON 3666 9806 3671 9852 3700 9850 3700 9801
TIME...MOT...LOC 0628Z 286DEG 35KT 3681 9827

SIX