Alert archive / Arizona / Flash Flood Warnings in 2019

Flash Flood Warning 51, NWS Flagstaff, AZ

August 28, 2019Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 28, 2019, 2:14 PM MST for Coconino County, Arizona. 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
Aug 28, 2019, 2:14 PM MST (21:14 UTC)
Expired
Aug 28, 2019, 5:15 PM MST
In force
3 hr
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon
Flood severity
None

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 150 km from the middle of the area, began a volume at 21:15 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.2 hours before the alert went out and 68 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, Flgstf/Belemont, AZ at 12:00Z on 2019-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2019-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2856 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
49 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 Flagstaff, AZ wrote its last area forecast discussion before this flash flood warning went out at Aug 28, 9:25 AM MST, 4 hours 49 minutes earlier.

Area forecast discussion, Aug 28, 9:25 AM MST, 4 hours 49 minutes before
Area Forecast Discussion
National Weather Service Flagstaff AZ
925 AM MST Wed Aug 28 2019

.SYNOPSIS...Expect an increase in afternoon chances for showers
and thunderstorms across northern Arizona through Thursday, before
chances decrease through Saturday. Otherwise, above normal
daytime temperatures and generally light winds are forecast.

&&

.UPDATE...
We are already seen isolated thunderstorms west of Seligman and
near Bitter Springs. We have increased storm chances this
afternoon for areas along and east or north of a line from Grey
Mountain-Flagstaff-White Mountains per latest HRRR and UA WRF
radar trends. Moisture and instability are decreasing as one
heads towards the 4 corners. We can add gusty outflow winds as
another storm hazards this afternoon, especially across the
Little Colorado River Valley.

&&

.PREV DISCUSSION /350 AM MST/...

Today...High temperatures today will be more moderate than the
record breaking conditions from earlier this work week. Although,
daytime temperatures will still be above average for the end of
August. An increase in monsoonal moisture will bring chances of
showers and thunderstorms to many locations today. Look for
convective initiation to begin in the late morning over the White
Mountains and the higher mountain peaks. Forecast upper-air
soundings show a general west to northwesterly mean wind this
afternoon and evening, which will create an east to southeastward
direction for storm movement. Localized heavy rainfall and hail
are a couple of the hazards that are possible with thunderstorms
today.

Thursday - Saturday...As the center of the high pressure shifts
westward again tonight into Thursday towards southern California,
slightly drier air will be transported into the County Warning
Area. There will be enough moisture in the lower and mid- levels
of the atmosphere that chances for showers and thunderstorms
remain in the forecast through Saturday. The greatest chances for
precipitation in this period will be Thursday and decrease each
day through Saturday. There could be slight variations in the PoPs
within this period as guidance continues to come into further
alignment where the deepest moisture and instability will set up.
Stay tuned.

Sunday & Beyond...The return of monsoonal moisture looks to be
setting up again on Sunday. Chances for thunderstorms and showers
on Sunday remain similar to previous forecasts, but were expanded
westward slightly towards west-central Coconino County. Long-
range guidance begins to diverge by Tuesday mid-day on the
placement of a trough setting up in the Pacific Northwest. This
will continue to be monitored and could impact how long the
moisture remains over northern Arizona next week.

&&

.AVIATION...For the 18Z package...Look for mostly VFR conditions
today with generally westerly winds of 10G20KT through the
afternoon, the exception being areas of MVFR conditions and 40 kt
outflow winds near convective activity. A few thunderstorms have
already kicked off this morning over northwestern Arizona indicating
the unstable airmass over the area. Expect scattered showers and
thunderstorms across much of northern AZ to the southwest of the
line KPGA-KRQE and numerous storms likely over the higher terrain of
mountains and ridges. These storms will continue through about 03
Thursday. Winds will become light and variable around sunset with
some lingering gusts in the Little Colorado Valley until 08Z.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...An increase in thunderstorm coverage is expected
today, with storm chances beginning to diminish again on Thursday.
Daytime temperatures will be about 5-10 degrees above normal.

Friday through Sunday...Storm coverage is expected to be limited on
Friday and Saturday, with continued well above normal daytime
temperatures. Storm coverage may begin to increase again on Sunday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

PUBLIC...DL/NL
AVIATION...DB
FIRE WEATHER...KD

For Northern Arizona weather information visit
weather.gov/flagstaff

In the hours before

Local storm report, Aug 28, 12:09 PM MST, 2 hours 5 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 27, 5:05 PM MSTFlash Flood WarningFGZGila3 hr
Aug 27, 6:49 PM MSTSevere Thunderstorm WarningFGZGila, Yavapai26 min
Aug 28, 10:59 AM MSTSevere Thunderstorm WarningFGZYavapai28 min
Aug 28, 11:51 AM MSTSevere Thunderstorm WarningFGZYavapai24 min
Aug 28, 1:15 PM MSTAreal Flood AdvisoryFGZNavajo2 hr
Aug 28, 1:56 PM MSTSevere Thunderstorm WarningFGZCoconino34 min
Aug 28, 2:22 PM MSTSpecial Weather StatementFGZ23 min
Aug 28, 2:33 PM MSTSevere Thunderstorm WarningFGZCoconino, Navajo42 min
Aug 28, 2:45 PM MSTAreal Flood AdvisoryFGZCoconino, Navajo3 hr
Aug 28, 3:15 PM MSTSevere Thunderstorm WarningFGZCoconino, Navajo45 min
Aug 28, 3:40 PM MSTFlash Flood WarningFGZCoconino, Navajo3 hr
Aug 28, 4:19 PM MSTSevere Thunderstorm WarningFGZGila, Navajo41 min

Nearby

Flash Flood Warnings in Arizona, 2019Every flash flood warning in 2019

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.