Alert archive / Texas / Flash Flood Warnings in 2018

Flash Flood Warning 58, NWS Norman, OK

September 21, 2018Knox County, Texas

NWS Norman, OK issued this flash flood warning at Sep 21, 2018, 10:47 AM CDT for Knox County, Texas. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Sep 21, 2018, 10:47 AM CDT (15:47 UTC)
Expired: Sep 21, 2018, 1:45 PM CDT
In force: 3 hr
Issued by: NWS Norman, OK
Area: Storm-based polygon
Flood severity: None

County Knox County, TX

The radar

The Altus AFB radar (KFDR), 110 km from the middle of the area, began a volume at 15:50 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

Fort Worth, TX (KFWD), launched 12:00Z, 3.8 hours before the alert went out and 244 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 294 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 805 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Sep 21, 6:08 AM CDT, 4 hours 39 minutes earlier.

Area forecast discussion, Sep 21, 6:08 AM CDT, 4 hours 39 minutes before

Area Forecast Discussion
National Weather Service Norman OK
608 AM CDT Fri Sep 21 2018

.DISCUSSION...

&&

.AVIATION...
For the 12z TAFs:

Periods of rain, occasionally heavy with visibility reductions
temporarily as low as 2 to 3 SM will occur at most TAF sites.
Gradual decrease in heavy rain potential will occur at most TAF
sites by later today. Thunderstorms are possible with occasional
lightning, but for most sites we handled this with VCTS. MVFR
ceilings should prevail through the TAF period except in northern
Oklahoma where a return to VFR is likely by late afternoon or
evening.

&&

.PREV DISCUSSION... /issued 353 AM CDT Fri Sep 21 2018/

DISCUSSION...
Heavy rainfall event continues to unfold with approaching cold
front, combined with phasing of northern/central plains s/wv trough
and weakening remnants of weak tropical disturbance. Greatest
influence of tropical moisture will remain confined to far southern
portions of Oklahoma and northern Texas late today through tomorrow
given delayed lower level return and advected layered precipitable
water trends. Highest QPF values are expected south of the OKC
metro, down toward Ardmore, Ada, and Durant and primarily from late
this afternoon through Saturday morning. Rainfall totals of 5 to 8
inches certainly appear possible over these areas. With heavier
precipitation ending across western parts of Oklahoma by evening, we
will move the expiration of the Flood Watch up to 00Z this evening
across the western-third or so of Oklahoma. Will keep rest of watch
going and let later shifts adjust as needed. 00Z NAM and last couple
runs of the ECM slow progression of southern wave over northern
Texas, allowing for heavy rainfall to potential last into much of
Saturday across the Red River Valley. Higher probabilities will be
maintained through the day.

In addition to the widespread rainfall, much cooler air will spread
into the region today and tonight. Below average temperatures will
be forecast through the weekend, with temperatures moderating on
Monday ahead of next frontal boundary. An evolving central U.S.
trough will be reflected at surface with passage of cold front on
Tuesday. Along with a downward trend in temperatures, rain chances
will return with this frontal boundary Tuesday into Wednesday. A
more clipper type system progd to dive into the northern plains
Wednesday into Thursday, allowing yet another front to move in late
in the week. This front has the potential to usher in the driest air
we have seen in quite some time, with dewpoints likely to fall into
the 40s over a larger area than currently forecast. With moisture
less abundant by this time, chances for showers and storms appears
lower and will keep pops at or below guidance values.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  75  59  71  60 / 100  90  40  20
Hobart OK         73  59  73  59 / 100  50  20  10
Wichita Falls TX  77  61  70  62 / 100  90  70  30
Gage OK           71  50  75  54 /  80   0   0  10
Ponca City OK     74  55  76  58 /  90  20  10  10
Durant OK         80  67  71  64 / 100 100  90  60

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch through Saturday afternoon for OKZ018>020-023>032-
     037>048-050>052.

     Flood Watch through this evening for OKZ014>017-021-022-033>036.

TX...Flood Watch through Saturday afternoon for TXZ084>090.

     Flood Watch through this evening for TXZ083.

&&

12/11

Hazardous weather outlook, Sep 21, 4:59 AM CDT, 5 hours 48 minutes before

Hazardous Weather Outlook
National Weather Service Norman OK
459 AM CDT Fri Sep 21 2018

OKZ004>048-050>052-TXZ083>090-221000-
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-
459 AM CDT Fri Sep 21 2018

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

.DAY ONE...Today and Tonight...

.Heavy Rainfall and Flooding...
Periods of rain will be heavy at times and this could cause
flooding of low-lying and poorly drained areas. The greatest
chance of flooding or flash flooding will be over the southern
half of Oklahoma and north Texas.

.Thunderstorms...
A few thunderstorms are possible today. Severe storms are not
expected.

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

.Heavy Rainfall and Flooding...
Heavy rain chances will continue through Saturday across southern
Oklahoma and north Texas. This could cause flooding of low-lying
and poorly drained areas.

.Thunderstorms...
A few thunderstorms are possible Saturday, mainly across southern
Oklahoma and north Texas. Low chances of storms will return
Monday and continue through next week. Severe storms are not
expected.

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

In the hours before

Local storm report, Sep 21, 9:16 AM CDT, 1 hour 31 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
916 AM CDT FRI SEP 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0857 AM     FLASH FLOOD      4 NW FILLMORE           34.32N 96.55W
09/21/2018                   JOHNSTON           OK   EMERGENCY MNGR

            8-INCHES OF WATER OVER ROADWAY AT
            INTERSECTIONS OF WILEY RD AND OLD CABIN RD.

&&

JP

Local storm report, Sep 21, 9:25 AM CDT, 1 hour 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
925 AM CDT FRI SEP 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0922 AM     FLASH FLOOD      CLARITA                 34.48N 96.43W
09/21/2018                   COAL               OK   EMERGENCY MNGR

            ROADWAYS UNDERWATER.

&&

TLINDLEY

Local storm report, Sep 21, 10:09 AM CDT, 38 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1009 AM CDT FRI SEP 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1005 AM     FLASH FLOOD      1 N PONTOTOC            34.51N 96.63W
09/21/2018                   PONTOTOC           OK   EMERGENCY MNGR

            HOUSE FLOODED.

&&

JP

Local storm report, Sep 21, 10:26 AM CDT, 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1026 AM CDT FRI SEP 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1023 AM     FLASH FLOOD      1 N PONTOTOC            34.51N 96.63W
09/21/2018                   JOHNSTON           OK   EMERGENCY MNGR

            8-INCHES OF WATER OVER THE ROADWAY ON EAST
            PONTOTOC RD.

&&

JP

Local storm report, Sep 21, 10:35 AM CDT, 12 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1035 AM CDT FRI SEP 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1010 AM     FLASH FLOOD      7 SW YUKON              35.44N 97.83W
09/21/2018                   CANADIAN           OK   BROADCAST MEDIA

            WATER WELL OVER ROADWAY AT INTERSECTIONS OF
            S. GREGORY RD AND SW 29TH ST. FROM KOCO TV.

&&

JP

Local storm report, Sep 21, 10:41 AM CDT, 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1041 AM CDT FRI SEP 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0940 AM     FLASH FLOOD      4 WNW CALUMET           35.62N 98.19W
09/21/2018                   CANADIAN           OK   EMERGENCY MNGR

            FLASH FLOODING OVER HWY 270.

&&

JP

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 20, 7:29 PM CDT	Special Weather Statement	OUN	Comanche, Cotton, Kiowa, Stephens, Tillman	31 min
Sep 20, 8:09 PM CDT	Special Weather Statement	OUN	Caddo	36 min
Sep 20, 8:30 PM CDT	Special Weather Statement	OUN	Custer	30 min
Sep 20, 9:12 PM CDT	Special Weather Statement	OUN	Blaine	33 min
Sep 20, 9:13 PM CDT	Special Weather Statement	OUN	Dewey	32 min
Sep 20, 9:14 PM CDT	Special Weather Statement	OUN	Greer	31 min
Sep 21, 7:57 AM CDT	Areal Flood Advisory	OUN	Coal, Johnston	3 hr
Sep 21, 8:23 AM CDT	Flash Flood Warning Emergency	OUN	Atoka, Coal, Johnston, Pontotoc	8 hr
Sep 21, 8:27 AM CDT	Areal Flood Advisory	OUN	Garvin, Murray, Pontotoc	3 hr
Sep 21, 8:33 AM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Kiowa	3 hr
Sep 21, 8:33 AM CDT	River Flood Warning	OUN	Carter, Garvin, Murray	22 hr
Sep 21, 8:35 AM CDT	River Flood Warning	OUN	Carter, Johnston, Murray	41 hr
Sep 21, 8:40 AM CDT	Areal Flood Advisory	OUN	Blaine, Caddo, Canadian, Kingfisher	3 hr
Sep 21, 8:40 AM CDT	River Flood Warning	OUN	Cotton	66 hr
Sep 21, 8:54 AM CDT	Areal Flood Advisory	OUN	Custer, Washita	3 hr
Sep 21, 9:22 AM CDT	Areal Flood Advisory	OUN	Carter, Comanche, Cotton, Garvin, Grady, Harmon and 5 more	3 hr
Sep 21, 9:45 AM CDT	Flash Flood Warning	OUN	Blaine, Canadian, Kingfisher	8 hr
Sep 21, 9:52 AM CDT	Areal Flood Advisory	OUN	Cleveland, McClain, Oklahoma	113 min
Sep 21, 10:03 AM CDT	Areal Flood Advisory	OUN	Carter, Johnston, Murray	3 hr
Sep 21, 10:17 AM CDT	Flash Flood Warning	OUN	Carter, Garvin, Johnston, Murray, Pontotoc, Stephens	3 hr
Sep 21, 10:39 AM CDT	Areal Flood Advisory	OUN	Lincoln, Payne	6 hr
Sep 21, 10:49 AM CDT	Areal Flood Advisory	OUN	Coal, Hughes, Pontotoc	3 hr
Sep 21, 11:47 AM CDT	Areal Flood Advisory	OUN	Cleveland, Garvin, McClain, Oklahoma	3 hr
Sep 21, 12:00 PM CDT	Areal Flood Advisory	OUN	Carter, Jefferson, Johnston, Love, Marshall	3 hr
Sep 21, 12:03 PM CDT	Flash Flood Warning	OUN	Cleveland, Garvin, McClain	5 hr
Sep 21, 12:16 PM CDT	Areal Flood Advisory	OUN	Comanche, Cotton, Jefferson, Stephens, Tillman	3 hr
Sep 21, 12:37 PM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Kiowa, Stephens	3 hr
Sep 21, 12:50 PM CDT	Flash Flood Warning	OUN	Cleveland, McClain, Oklahoma	4 hr
Sep 21, 12:57 PM CDT	Flash Flood Warning	OUN	Carter, Jefferson, Johnston, Love, Marshall, Murray and 1 more	6 hr
Sep 21, 1:12 PM CDT	Flash Flood Warning	OUN	Carter, Garvin, Johnston, Murray, Pontotoc, Stephens	7 hr
Sep 21, 1:26 PM CDT	Flash Flood Warning	OUN	Coal, Hughes, Pontotoc	3 hr
Sep 21, 2:10 PM CDT	River Flood Warning	OUN	Bryan	3 days
Sep 21, 2:12 PM CDT	River Flood Warning	OUN	Atoka	5 days
Sep 21, 2:24 PM CDT	Flash Flood Warning	OUN	Cotton, Jefferson	3 hr
Sep 21, 2:29 PM CDT	Areal Flood Advisory	OUN	Comanche, Jackson, Kiowa, Tillman	3 hr
Sep 21, 2:51 PM CDT	Areal Flood Advisory	OUN	Cleveland, Lincoln, Oklahoma, Pottawatomie, Seminole	3 hr
Sep 21, 3:13 PM CDT	Areal Flood Advisory	OUN	Comanche, Cotton, Jefferson, Stephens, Tillman	3 hr
Sep 21, 3:31 PM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Kiowa, Stephens	3 hr
Sep 21, 3:48 PM CDT	Flash Flood Warning	OUN	Caddo, Comanche, Kiowa, Tillman	3 hr
Sep 21, 4:15 PM CDT	Flash Flood Warning	OUN	Coal, Hughes, Pontotoc	4 hr
Sep 21, 4:36 PM CDT	Flash Flood Warning	OUN	Atoka, Coal, Johnston, Pontotoc	4 hr
Sep 21, 5:06 PM CDT	Areal Flood Warning	OUN	Cleveland, McClain, Oklahoma	3 hr
Sep 21, 5:18 PM CDT	Areal Flood Warning	OUN	Cleveland, Garvin, McClain	3 hr
Sep 21, 5:25 PM CDT	Areal Flood Warning	OUN	Cotton, Jefferson	3 hr
Sep 21, 5:32 PM CDT	Areal Flood Advisory	OUN	Lincoln, Pottawatomie, Seminole	3 hr
Sep 21, 5:35 PM CDT	Areal Flood Warning	OUN	Blaine, Canadian, Kingfisher	3 hr
Sep 21, 5:42 PM CDT	Areal Flood Advisory	OUN	Grady	3 hr
Sep 21, 6:05 PM CDT	Areal Flood Advisory	OUN	Atoka, Bryan, Johnston, Marshall	3 hr
Sep 21, 6:48 PM CDT	Areal Flood Warning	OUN	Carter, Jefferson, Johnston, Love, Marshall, Murray	4 hr
Sep 21, 10:28 AM CDT	Areal Flood Advisory	OUN	Archer, Baylor, Clay, Foard, Knox, Wichita and 1 more	3 hr
Sep 21, 12:46 PM CDT	Flash Flood Warning	OUN	Baylor, Foard, Knox, Wichita, Wilbarger	3 hr
Sep 21, 1:33 PM CDT	Areal Flood Advisory	OUN	Archer, Baylor, Clay, Wichita	3 hr
Sep 21, 2:13 PM CDT	River Flood Warning	OUN	Wichita, Wilbarger	48 hr
Sep 21, 2:37 PM CDT	River Flood Warning	OUN	Baylor, Knox	31 hr
Sep 21, 3:39 PM CDT	Areal Flood Warning	OUN	Baylor, Knox, Wichita, Wilbarger	3 hr
Sep 21, 4:20 PM CDT	Areal Flood Advisory	OUN	Archer, Baylor, Wichita	3 hr

Nearby

Flash Flood Warnings in Texas, 2018 Every flash flood warning in 2018

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.