Special Weather Statement, NWS Norman, OK

Area Forecast Discussion
National Weather Service Norman OK
305 PM CDT Sun Jun 6 2021

...New LONG TERM...

.SHORT TERM...
(This evening through Monday)
Issued at 222 PM CDT Sun Jun 6 2021

Complex scenario will continue tonight into Monday as upper low
fills and opens ups as it moves ever so slowly northeast.

Had a few storms this morning and storms have begun to develop this
afternoon. Expect to see this activity continue through the
afternoon hours across parts of central and south/southeastern
Oklahoma. Quite a bit of instability, but not much shear. Storms
will likely be pulse-type producing some marginally severe hail and
perhaps some gusty wind as well as heavy rainfall. Expect a lull in
the activity late this afternoon into the early/mid evening.

Later this evening, anticipate additional shower/thunderstorm
development to occur with main areas being across parts of
western/southwestern Oklahoma into north Texas as well as to our
west across west Texas. Activity over our area, possible developing
in the late evening hours, expected to be in response to minor
disturbance rotating around western side of upper low coinciding
with developing llj. Although instability will be decreasing due to
loss of daytime insolation, bulk shear will increase, which should
allow at least some potential for strong to severe storms with this
activity. Slow movement and high PWATs will also result in higher
rainfall rates and some localized flooding.

Meanwhile, expect to see convection develop portions of eastern New
Mexico as minor shortwave moves east out of the southern Rockies.

Several models including HRRR, GFS as well as others support some of
the higher terrain convection making it far enough east to congeal
with the activity already in Oklahoma/north Texas. This complex then
moves/develops east and southeast. Exact location and strength of
this complex is still in question, but most likely area/s would be
southern Oklahoma southward into north Texas.

Expect to see some lingering shower/thunderstorm activity across
parts of south/southeast Oklahoma Monday morning. Although a
downward trend in coverage is anticipated, additional activity will
remain possible during the day as upper low continues to translate
northeast away from the area.

&&

.LONG TERM...
(Monday night through next Saturday)
Issued at 305 PM CDT Sun Jun 6 2021

By Monday evening through the overnight hours, expecting the upper
low to be centered over the U.S. Midwest, with the opened trough in
place across the Southern Plains.  A southerly low-level jet will be
developing across northeast Texas through southwestern Oklahoma
transporting gulf moisture and increasing the low-level shear.  With
a mid-level vort max in the upper wave above the low-level jet,
would expect the vertical ascent to be sufficient enough to develop
some convection, as mid-level cooling southwest of the upper low
should maintain an unstable environment aloft.  As a result, will
maintain chance POPs in the grids Monday evening and overnight
across southeast and southcentral Oklahoma, to slight chances across
central Oklahoma.  Models differ with the degree of instability
aloft, with both NAM & GFS stronger with up to 2000 J/kg of MUCAPE
in our POP area, while the ECMWF is a bit weaker up to 1000 J/kg. Of
course the convection expected during the short term of the forecast
may also affect the degree of instability late Monday, which also
adds to the uncertainty.  At least based on the more aggressive NAM,
cannot completely rule out a few strong to marginally severe storms.
Ongoing and additional flooding may also be affecting southern
portions of our CWA due to excessive rainfall.  Although both NAM &
Canadian NH models project a bullseye of over two inches of
preciptable water across northeast Texas through Arkansas, southeast
Oklahoma will be approaching two inches Monday night.  At least for
now, a marginal potential for flash flooding across southcentral
through southeast Oklahoma will be the primary hazard to deal with
for Monday night.  With an upper ridge starting to build in from the
west, expecting the trough to move off to the east with the storm
POPs decreasing by Tuesday afternoon.

As the upper ridge continues to build, our entire forecast area
should remain dry through the remainder of the week.  However,
unseasonably hot and muggy summerlike conditions will be the main
issues. Breezy south winds will continue to advect hot and humid
air.  The moisture advection will create a dryline across the
Southern High Plains, with the most abundant moisture of muggy 70-75
degree dewpoints across the central one third of Oklahoma.  Although
slightly drier, much of western Oklahoma and western north Texas
should still see triple digit high temperatures on Wednesday &
Thursday afternoons, while most areas west of I-35 will feel triple
digit heat index values between 100-105 degrees. We should see a
little bit of relief from the heat beginning Friday across northern
Oklahoma and by Saturday across the remainder of our area.  On
Friday, an upper wave digging across the U.S. Northern Plains will
be pushing a surface low across the Central Plains with a dry cold
front moving into northwest Oklahoma, then across most of our area
overnight.  The slightly cooler air should bring temperatures back
down close to seasonably average into the weekend.  A short-wave
ripple in our upper ridge could bring our next chance for storms
across northwest Oklahoma on Sunday.

&&

.AVIATION...
(18Z TAFS)
Issued at 1206 PM CDT Sun Jun 6 2021

Abundant moisture will allow some MVFR ceilings to continue this
afternoon with some improvement this evening. There will also be
a chance for thunderstorm development across parts of central
Oklahoma this afternoon with a better chance overnight into Monday
morning across the western half of Oklahoma southward into north
Texas. Expect to see MVFR ceilings redevelop late tonight and
continue through end of forecast period. Mainly south/southeast
winds with daytime speeds around 12kts with lighter winds
overnight.

&&

.UPPER AIR...
Issued at 241 AM CDT Thu Jun 3 2021

No Upper Air flights are currently planned.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  66  82  68  85 /  50  60  30  10
Hobart OK         66  86  68  91 /  60  30  20   0
Wichita Falls TX  68  86  70  91 /  80  60  30  10
Gage OK           65  88  67  90 /  30  10  10   0
Ponca City OK     66  83  67  86 /  30  50  20  10
Durant OK         67  81  69  85 /  50  70  60  30

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

SHORT TERM...30
LONG TERM....68
AVIATION...30

Hazardous Weather Outlook
National Weather Service Norman OK
1151 AM CDT Sun Jun 6 2021

OKZ004>048-050>052-TXZ083>090-071700-
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-
1151 AM CDT Sun Jun 6 2021

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

.DAY ONE...Through Tonight...

.Thunderstorms...
There is a Marginal Risk of severe thunderstorms this afternoon
and tonight across approximately the southern half of Oklahoma
and all of western north Texas.

Isolated strong to severe thunderstorms are possible this afternoon
with a lull in thunderstorms expected during most of the evening.
Scattered to numerous thunderstorms, some potentially strong to
severe, are expected to redevelop late this evening into the
overnight hours.

The primary severe weather hazards will be hail up to the size of
half dollars and wind gusts of 60 to 70 mph. In addition, locally
heavy rainfall is possible. Thunderstorms may cause localized
flooding with high rainfall rates and slow movement.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...
Storm spotter groups and emergency management personnel should
prepare for severe weather operations through tonight.

.DAYS TWO THROUGH SEVEN...Monday through Saturday...

.Thunderstorms...
Scattered thunderstorms will continue and redevelop on Monday with
thunderstorm chances continuing through Tuesday. The potential for
severe weather will be low on Monday and Tuesday.

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

Mahale

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
146 PM CDT Sun Jun 6 2021

OKZ023-027-061930-
Grady OK-Caddo OK-
146 PM CDT Sun Jun 6 2021

...SIGNIFICANT WEATHER ADVISORY FOR northwestern Grady and east
central Caddo Counties Until 230 PM CDT...

AT 144 PM CDT, a strong thunderstorm was located near Lake Chickasha,
moving east at 5 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 50 MPH...
Heavy rain can lead to reduced visibility...

Locations impacted include...
Lake Chickasha.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 3507 9822 3521 9824 3530 9803 3519 9798
      3510 9799
TIME...MOT...LOC 1844Z 256DEG 6KT 3515 9817

Mahale

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
249 PM CDT Sun Jun 6 2021

OKZ023-027-062015-
Grady OK-Caddo OK-
249 PM CDT Sun Jun 6 2021

...SIGNIFICANT WEATHER ADVISORY FOR west central Grady and east
central Caddo Counties Until 315 PM CDT...

AT 245 PM CDT, a strong thunderstorm was located near Gracemont,
moving northeast at 10 MPH.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 3508 9824 3517 9834 3535 9821 3520 9797
TIME...MOT...LOC 1945Z 220DEG 7KT 3517 9823

30

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
313 PM CDT Sun Jun 6 2021

OKZ025-029-062100-
Oklahoma OK-Cleveland OK-
313 PM CDT Sun Jun 6 2021

...SIGNIFICANT WEATHER ADVISORY FOR southeastern Oklahoma and
northeastern Cleveland Counties Until 400 PM CDT...

AT 312 PM CDT, a strong thunderstorm was located over southeastern
Oklahoma City, moving northeast at 15 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts over 50 MPH...
Heavy rain can lead to reduced visibility...
Frequent cloud to ground lightning...

Locations impacted include...
Southeastern Oklahoma City, northern Norman, Moore, Midwest City,
Choctaw, Stanley Draper Lake, Stella, Tinker Air Force Base and
northern Lake Thunderbird.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 3523 9744 3530 9750 3550 9727 3532 9715
TIME...MOT...LOC 2012Z 236DEG 15KT 3530 9741

03