Scattered to numerous showers and storms formed with the aid of a front under southwest flow on the afternoon of the 5th. Heavy rainfall and training storms resulting a few reports of flash flooding.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS OUN wrote it up.
Scattered to numerous showers and storms formed with the aid of a front under southwest flow on the afternoon of the 5th. Heavy rainfall and training storms resulting a few reports of flash flooding.
The local office's own words before the first event, 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 the first event at Sep 5, 1:39 PM CST, 1 hour 53 minutes earlier.
Area Forecast Discussion
National Weather Service Norman OK
239 PM CDT Wed Sep 5 2018
.DISCUSSION...
Locally heavy rainfall amounts and flooding/flash flooding is the
primary concern over the next couple of days.
The large scale pattern remains similar to previous days. A ribbon
of deep tropical moisture continues to stream northward through the
southern Plains connected to eastward moving shortwave trough over
the upper Midwest. 1200 UTC sounding at both Norman and Lamont
measured around 2.10 inches of precipitable water which is quite
anomalous and just above the max 15 day moving average in SPC
sounding climatology. Warm cloud depth is quite extensive too with
low cloud bases and very moist/saturated profile up through the
freezing level supporting a warm rain process. For this reason, we
continue to have KTLX and KVNX in Tropical Z-R (re: latest Free
Text Messages).
This does not quite fit the conceptual model for a Predecessor Rain
Event (PRE) given the placement of key features, but several
elements are in play for locally heavy rainfall, hence the late
morning issuance of a focused Flood Watch. This was primary driven
by trends on the mesoscale supported by output from several CAMs.
Latest observations show a few areas of weak confluence within a
narrow zone where partial clearing has led to modest destabilization
from central into south-central Oklahoma. Scattered to numerous
convective cells have developed in this area. These will
persist/expand producing locally heavy rainfall amounts through the
afternoon into early evening before gradually decreasing. A more
significant/organized convective event would occur if we had more
large scale forcing.
850-300 hPa flow should result in slow northeast movement around 5-
10 mph of individual cells. The main flooding threat will be over
areas with saturated ground and lower one hour Flash Flood Guidance
(i.e., portions of Cleveland, Oklahoma, Pottawatomie, and Lincoln
counties, and extending into the terrain of the Arbuckles).
The aforementioned shortwave that passed well to our north sent a
cold front southward into northwest Oklahoma, and short term model
guidance shows the front continuing to move south but becoming more
diffuse later this evening and overnight. Meanwhile, over a broader
area, flow is expected to become more easterly and eventually
northeasterly in response to the remnants of Tropical Depression
Gordon approaching. We're already seeing convection increase near
the front over north-central Oklahoma from near Cherokee to Fairview
and continued expansion and southwestward development is anticipated
this afternoon into the evening. This is in an area of relatively
high Flash Flood Guidance, but localized amounts may still be
sufficient for flooding and an expansion of the Flood Watch may
become necessary.
Current thinking is that as convection across central Oklahoma into
north Texas slowly decreases this evening, the focus will shift west
into northwest and west-central Oklahoma, and eventually further
south into southwest Oklahoma and western north Texas. This may
persist into the morning and then expand again across much of the
area again tomorrow with diurnal heating and modest destabilization.
The most numerous showers and storms tomorrow should be
coincident with low/near-zero T/Td depressions at 500 hPa,
coincident with the axis of highest precipitable water which is
expected to still be quite anomalous. Thursday night into Friday,
we didn't make much changes highest rain probabilities and have
most of the area covered in mid-high range chance category. We'll
be able to better refine areas that have highest chances once we
can better pin down mesoscale details.
Deterministic and ensemble guidance remains consistent in tracking
the remnants of Gordon into eastern Oklahoma by Friday evening.
Strengthening northeasterly flow and decreasing low theta-e values
will limit convective coverage into Saturday, especially across
the northwest two-thirds of the area. Rain chances decrease
considerably Sunday as a strengthening trough encourages Gordon's
remnants to move northeast of the region. Weak west-northwesterly
flow and below climo moisture should mean dry conditions the first
part of next week with a warming trend as mid-level heights/mean
ridging builds across the Plains.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 70 80 70 80 / 40 60 50 50
Hobart OK 70 80 68 79 / 50 60 50 50
Wichita Falls TX 72 81 71 83 / 40 60 50 50
Gage OK 65 77 65 76 / 60 40 30 30
Ponca City OK 74 80 70 78 / 50 50 40 50
Durant OK 72 88 72 86 / 20 30 20 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch until 9 PM CDT this evening for OKZ007-008-012-013-
018>020-023>032-038>042.
TX...None.
&&
26/12Hazardous Weather Outlook...UPDATED National Weather Service Norman OK 1136 AM CDT Wed Sep 5 2018 OKZ004>048-050>052-TXZ083>090-061645- 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- 1136 AM CDT Wed Sep 5 2018 This hazardous weather outlook is for portions of northern... western...central...and southern Oklahoma...and western north Texas. .DAY ONE...Through Tonight... .Thunderstorms... A few thunderstorms are possible today and tonight, but severe storms are not expected. .Heavy Rain/Flooding... Locally heavy rainfall amounts are likely with showers and thunderstorms. Locations that see persistent, heavy rainfall could experience flooding or flash flooding. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday... .Thunderstorms... The chance for thunderstorms will continue across Oklahoma and western north Texas through Saturday followed by lower chances Sunday and Monday across southeast Oklahoma. Areas of heavy rainfall and flooding will be possible. The potential for severe storms will remain low. Get graphics and more details at weather.gov/norman...and follow our weather forecast office on Twitter and Facebook.
The national radar mosaic for the moment the first event began.
3 flood. Local standard time, as filed.
Minor street flooding occurred on Broadway Ave in Elk City.
Street flooding occurred on Kelly avenue between 33rd and 15th streets.
Street flooding occurred on Shartel near NW 36th street.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oklahoma in 2018Every state in 2018This day in weather historyWarnings in Oklahoma, September 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 786602, 786847, 786850.