Alert archive / Oklahoma / Flash Flood Warnings in 2020

Flash Flood Warning 14, NWS Norman, OK

May 15, 2020Garvin County, Stephens County, Oklahoma

NWS Norman, OK issued this flash flood warning at May 15, 2020, 6:44 PM CDT for Garvin County, Stephens County, Oklahoma. It was in force for 91 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 15, 2020, 6:44 PM CDT (23:44 UTC)
Expired
May 15, 2020, 8:15 PM CDT
In force
91 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Flood severity
None

Counties Garvin County, OK, Stephens County, OK

The radar

The Norman radar (KTLX), 87 km from the middle of the area, began a volume at 23:48 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.7 hours before the alert went out and 71 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2020-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1862 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 12:00Z on 2020-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 292 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1862 J/kg
Mixed-layer CIN
-241 J/kg
Mixed-layer LCL
909 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
292 m²/s²
0-3 km storm-relative helicity
249 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Norman, OK wrote its last area forecast discussion before this flash flood warning went out at May 15, 6:17 PM CDT, 27 minutes earlier.

Area forecast discussion, May 15, 6:17 PM CDT, 27 minutes before
Area Forecast Discussion
National Weather Service Norman OK
617 PM CDT Fri May 15 2020

...New AVIATION...

.SHORT TERM...
(This evening through Saturday)
Issued at 228 PM CDT Fri May 15 2020

The outflow boundary/front across south-central Oklahoma, and
back northwest into west-central Oklahoma around mid-afternoon
will likely continue its southwestward progress, although probably
with less enthusiasm in the west. The storms forming behind the
front will continue to reinforce its southward movement in the
area east of I-44. This boundary's location will have major
implications on severe weather and flooding probabilities this
evening. The deeper into the cooler air, the lower the risk of
major severe weather...and flooding will be mainly near and up to
about 50 miles north of the boundary (although the risk of
flooding may expand late this evening, as storms become less
reliant on surface conditions).

We currently expect the majority of the rain and severe weather to
be over the southern half of our forecast area this evening (high
rain chances will continue through the night in the south). With
slow movement of the storms, and heavy rainfall from many of the
storms, there will be a risk of flooding. We are continuing the
existing Flood Watch.

Another cold front is expected to move into Oklahoma tomorrow,
joining an MCV that is likely to be over southern Oklahoma during
the day. This will support disorganized shower and thunderstorm
development over much of Oklahoma/north Texas, although by
afternoon, I-35 will divide the "likely" area (to the east of
I-35) from the "chance" area (to the west). Instability east of
I-35 may support a few strong storms, but organized severe storms
are not currently expected.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 228 PM CDT Fri May 15 2020

Showers/thunderstorms will be decreasing from the northwest
Saturday evening into early Sunday, as an upper-level circulation
departs to the south/southeast. This will leave Oklahoma and north
Texas under upper-level ridging, which will be reinforced by an
omega pattern early in the week.

Medium-range models are still a bit offset from each other
regarding the ridge axis location around midweek. For now, we have
a mild and dry (no rain) forecast for next week. If the ridge
shifts east more than currently expected, rain chances and
temperatures will both go up.

&&

.AVIATION...
(00Z TAFS)
Issued at 613 PM CDT Fri May 15 2020

A thunderstorm complex over Oklahoma and Texas will cause chaotic
weather, including a few severe thunderstorms, across the area
this evening. Highly variable winds, ceilings, and visibilities
are to be expected, particularly south of KCSM-KOKC through at
least 05Z. Farther north, winds will be affected by outflow from
the storm complex.

It is unclear whether there will be BR/fog early Saturday, but
with the cloud cover from the storms, and little or no rainfall
near the edges of the cloud shield, BR/fog seems unlikely.

There will be a few scattered showers, perhaps thunderstorms, on
Saturday, mainly in the afternoon, and mainly east of I-35. Winds
will be all over the compass, but should be relatively light
outside showers and storms.

CmS
&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  63  77  62  78 /  70  50  30   0
Hobart OK         62  80  60  81 /  70  30  20   0
Wichita Falls TX  63  79  64  84 /  80  40  20   0
Gage OK           58  81  56  80 /  40  40  20   0
Ponca City OK     63  79  59  77 /  50  60  30   0
Durant OK         65  76  64  80 /  60  80  50  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch through Saturday morning for OKZ027>032-037>048-
     050>052.

TX...Flood Watch through Saturday morning for TXZ085-086-088>090.

&&

SHORT TERM...23
LONG TERM....23
AVIATION...23
Hazardous weather outlook, May 15, 2:12 PM CDT, 4 hours 32 minutes before
Hazardous Weather Outlook...UPDATED
National Weather Service Norman OK
212 PM CDT Fri May 15 2020

OKZ004>048-050>052-TXZ083>090-161915-
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-
212 PM CDT Fri May 15 2020

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 risk of severe storms through this evening, mainly near
and south of I-40. Large hail up to the size of baseballs and
damaging winds up to 80 mph are the main concerns. The potential
for a tornado is very low.

.Heavy Rain...
There is a potential for heavy rain that could lead to flooding
through tonight, mainly across portions of central and southern
Oklahoma, and western north Texas.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...

Storm spotter groups and emergency management personnel across the
risk area should prepare for severe weather operations through
the evening hours..

.DAYS TWO THROUGH SEVEN...Saturday through Thursday...

.Thunderstorms...
The chance for thunderstorms will continue on Saturday, with a
lower risk for strong to severe thunderstorms. The strongest
storms are expected to be near and east of I-35. Low thunderstorm
chances will continue across southeast Oklahoma on Sunday.

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

In the hours before

Special weather statement, May 15, 6:20 PM CDT, 24 minutes before
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Local storm report, May 15, 6:28 PM CDT, 16 minutes before
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Local storm report, May 15, 6:29 PM CDT, 15 minutes before
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Local storm report, May 15, 6:35 PM CDT, 9 minutes before
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Local storm report, May 15, 6:39 PM CDT, 5 minutes before
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Local storm report, May 15, 6:43 PM CDT, 1 minute before
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The office that day

Everything else NWS Norman, OK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 14, 8:10 PM CDTSpecial Weather StatementOUNMajor35 min
May 14, 8:17 PM CDTSevere Thunderstorm WarningOUNMajor, Woods, Woodward43 min
May 14, 8:25 PM CDTSpecial Weather StatementOUNEllis35 min
May 14, 8:52 PM CDTSevere Thunderstorm WarningOUNMajor, Woods68 min
May 14, 9:04 PM CDTSpecial Weather StatementOUNEllis26 min
May 14, 9:10 PM CDTSevere Thunderstorm WarningOUNDewey, Ellis, Woodward50 min
May 14, 9:26 PM CDTSpecial Weather StatementOUNEllis34 min
May 14, 9:41 PM CDTSevere Thunderstorm WarningOUNEllis, Harper, Woodward49 min
May 14, 9:51 PM CDTSevere Thunderstorm WarningOUNBlaine, Major, Woods54 min
May 14, 10:19 PM CDTAreal Flood AdvisoryOUNMajor3 hr
May 14, 10:31 PM CDTSevere Thunderstorm WarningOUNBlaine, Major, Woods59 min
May 14, 11:23 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Major, Woods52 min
May 15, 12:07 AM CDTSevere Thunderstorm WarningOUNGarfield, Kingfisher, Major32 min
May 15, 1:18 AM CDTSpecial Weather StatementOUNGarfield27 min
May 15, 10:59 AM CDTFlood WatchOUNAtoka, Bryan, Carter, Cleveland, Coal, Comanche and 17 more16 hr
May 15, 12:16 PM CDTSpecial Weather StatementOUNHughes29 min
May 15, 12:32 PM CDTSpecial Weather StatementOUNPottawatomie28 min
May 15, 12:41 PM CDTSevere Thunderstorm WarningOUNCleveland, Pottawatomie49 min
May 15, 12:57 PM CDTAreal Flood AdvisoryOUNHughes, Pottawatomie, Seminole3 hr
May 15, 1:13 PM CDTSevere Thunderstorm WarningOUNCleveland, McClain, Pottawatomie47 min
May 15, 1:27 PM CDTSpecial Weather StatementOUNCleveland33 min
May 15, 1:38 PM CDTAreal Flood AdvisoryOUNCleveland, Pottawatomie3 hr
May 15, 1:40 PM CDTSevere Thunderstorm WarningOUNCleveland, McClain35 min
May 15, 2:15 PM CDTSpecial Weather StatementOUNMcClain30 min
May 15, 2:20 PM CDTSpecial Weather StatementOUNGrady25 min
May 15, 2:21 PM CDTAreal Flood AdvisoryOUNCleveland, Garvin, Grady, McClain, Stephens114 min
May 15, 2:42 PM CDTSpecial Weather StatementOUNGarvin, Grady33 min
May 15, 2:57 PM CDTSevere Thunderstorm WarningOUNGrady33 min
May 15, 3:07 PM CDTSevere Thunderstorm WarningOUNCaddo, Comanche, Grady23 min
May 15, 3:12 PM CDTAreal Flood AdvisoryOUNCaddo, Comanche, Grady63 min
May 15, 3:21 PM CDTSpecial Weather StatementOUNPontotoc39 min
May 15, 3:26 PM CDTSevere Thunderstorm WarningOUNCaddo, Comanche, Grady34 min
May 15, 3:31 PM CDTFlash Flood WarningOUNCaddo, Comanche, Grady, Stephens119 min
May 15, 3:33 PM CDTSpecial Weather StatementOUNStephens27 min
May 15, 3:40 PM CDTSpecial Weather StatementOUNJackson50 min
May 15, 3:47 PM CDTSpecial Weather StatementOUNCoal43 min
May 15, 3:47 PM CDTSevere Thunderstorm WarningOUNComanche43 min
May 15, 3:48 PM CDTSpecial Weather StatementOUNGarvin27 min
May 15, 4:00 PM CDTSpecial Weather StatementOUNCaddo30 min
May 15, 4:07 PM CDTSpecial Weather StatementOUNAtoka53 min
May 15, 4:10 PM CDTSevere Thunderstorm WarningOUNComanche, Grady, Stephens35 min
May 15, 4:13 PM CDTFlash Flood WarningOUNCarter, Garvin, Murray, Stephens3 hr
May 15, 4:15 PM CDTRiver Flood WarningOUNPottawatomie, Seminole11 hr
May 15, 4:17 PM CDTSpecial Weather StatementOUNGarvin28 min
May 15, 4:22 PM CDTSpecial Weather StatementOUNHarmon53 min
May 15, 4:28 PM CDTSpecial Weather StatementOUNKiowa17 min
May 15, 4:28 PM CDTSevere Thunderstorm WarningOUNCarter, Garvin, Murray47 min
May 15, 4:43 PM CDTSevere Thunderstorm WarningOUNGrady, Stephens32 min
May 15, 4:53 PM CDTSpecial Weather StatementOUNComanche37 min
May 15, 4:59 PM CDTSevere Thunderstorm WarningOUNHarmon, Jackson61 min
May 15, 5:03 PM CDTSpecial Weather StatementOUNBryan42 min
May 15, 5:12 PM CDTSevere Thunderstorm WarningOUNGarvin, Grady, Stephens33 min
May 15, 5:13 PM CDTSpecial Weather StatementOUNGarvin47 min
May 15, 5:16 PM CDTSevere Thunderstorm WarningOUNJackson44 min
May 15, 5:18 PM CDTSpecial Weather StatementOUNMurray72 min
May 15, 5:22 PM CDTSpecial Weather StatementOUNGrady23 min
May 15, 5:23 PM CDTAreal Flood AdvisoryOUNCoal, Garvin, Murray, Pontotoc, Seminole2 hr
May 15, 5:23 PM CDTSpecial Weather StatementOUNKiowa37 min
May 15, 5:28 PM CDTFlash Flood WarningOUNCaddo, Comanche, Cotton, Garvin, Grady, Stephens92 min
May 15, 5:32 PM CDTAreal Flood AdvisoryOUNComanche, Jackson, Kiowa, Tillman118 min
May 15, 5:35 PM CDTSevere Thunderstorm WarningOUNCaddo25 min
May 15, 5:41 PM CDTAreal Flood AdvisoryOUNHarmon, Jackson2 hr
May 15, 5:41 PM CDTSpecial Weather StatementOUNCaddo34 min
May 15, 5:48 PM CDTSpecial Weather StatementOUNTillman42 min
May 15, 5:52 PM CDTSpecial Weather StatementOUNStephens23 min
May 15, 5:57 PM CDTSevere Thunderstorm WarningOUNJackson, Kiowa, Tillman63 min
May 15, 5:58 PM CDTSpecial Weather StatementOUNStephens32 min
May 15, 6:03 PM CDTSevere Thunderstorm WarningOUNStephens27 min
May 15, 6:04 PM CDTFlash Flood WarningOUNComanche, Jackson, Kiowa, Tillman3 hr
May 15, 6:06 PM CDTSevere Thunderstorm WarningOUNCaddo, Grady8 min
May 15, 6:12 PM CDTSevere Thunderstorm WarningOUNTillman63 min
May 15, 6:20 PM CDTSpecial Weather StatementOUNComanche25 min
May 15, 6:25 PM CDTSevere Thunderstorm WarningOUNComanche26 min
May 15, 6:26 PM CDTSevere Thunderstorm WarningOUNStephens34 min
May 15, 6:35 PM CDTSevere Thunderstorm WarningOUNJackson, Kiowa, Tillman40 min
May 15, 6:57 PM CDTSevere Thunderstorm WarningOUNGarvin, Stephens48 min
May 15, 6:58 PM CDTSevere Thunderstorm WarningOUNJackson, Tillman77 min
May 15, 6:59 PM CDTFlash Flood WarningOUNCaddo, Comanche, Grady, Tillman3 hr
May 15, 4:48 PM CDTSpecial Weather StatementOUNHardeman42 min
May 15, 5:56 PM CDTSevere Thunderstorm WarningOUNHardeman64 min

Nearby

Flash Flood Warnings in Oklahoma, 2020Every flash flood warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.