Alert archive / Colorado / Areal Flood Advisories in 2015

Areal Flood Advisory 21, NWS Denver/Boulder, CO

May 23, 2015Logan County, Colorado

NWS Denver/Boulder, CO issued this areal flood advisory at May 23, 2015, 5:38 PM MDT for Logan County, Colorado. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
May 23, 2015, 5:38 PM MDT (23:38 UTC)
Expired
May 23, 2015, 8:00 PM MDT
In force
2 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon

County Logan County, CO

The radar

The Cheyenne radar (KCYS), 150 km from the middle of the area, began a volume at 23:39 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

Denver, CO (KDEN), launched 12:00Z, 11.6 hours before the alert went out and 96 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, Denver, CO at 12:00Z on 2015-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 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, Denver, CO at 12:00Z on 2015-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -18 square meters per square second.1939587897117Sfc1 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
1 J/kg
Mixed-layer CIN
-241 J/kg
Mixed-layer LCL
762 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
67 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 areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this areal flood advisory went out at May 23, 3:21 PM MDT, 2 hours 17 minutes earlier.

Area forecast discussion, May 23, 3:21 PM MDT, 2 hours 17 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>
Hazardous weather outlook, May 23, 11:11 AM MDT, 6 hours 27 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1111 AM MDT SAT MAY 23 2015

COZ030>051-241715-
JACKSON COUNTY BELOW 9000 FEET-
WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET-
GRAND AND SUMMIT COUNTIES BELOW 9000 FEET-
SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-
SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/
GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE
9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-
JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR
CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET-
CENTRAL AND SOUTHEAST PARK COUNTY-
LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-
BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD
COUNTY-
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND
ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY-
ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-
NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY-
CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-
SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY-
LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY-
1111 AM MDT SAT MAY 23 2015

...STRONG THUNDERSTORMS EXPECTED TO MOVE OVER NORTHEAST COLORADO
THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

AN UPPER LEVEL STORM SYSTEM OVER EASTERN UTAH TODAY WILL MOVE
SLOWLY INTO WESTERN COLORADO BY TONIGHT. THIS SYSTEM WILL COMBINE
WITH ABUNDANT MOISTURE ACROSS EASTERN COLORADO TO PRODUCE ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE AREA THIS
AFTERNOON AND EARLY EVENING.

A FEW SEVERE STORMS WILL BE POSSIBLE OVER THE PLAINS OF NORTHEAST
COLORADO THROUGH THE AFTERNOON WITH LARGE HAIL AND A FEW
TORNADOES. IN ADDITION...THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL WITH 1 TO 2 INCHES OF RAIN IN 30 MINUTES
OR LESS. WHEN THE HEAVY RAINS DEVELOP...FLASH FLOODING WILL
QUICKLY RESULT DUE TO THE SATURATED SOIL CONDITIONS. PEOPLE
SHOULD REMAIN ALERT FOR RAPIDLY CHANGING CONDITIONS THROUGH THE
AFTERNOON. THUNDERSTORMS WILL GENERALLY BE MOVING FROM SOUTH TO
NORTH...AND MULTIPLE WAVES OF STORMS WILL BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SUBTLE DAY TO DAY TEMPERATURE AND PRECIPITATION CHANCES ARE IN
STORE FOR THE FORECAST AREA DURING THE UPCOMING WEEK. SUNDAY AND
WEDNESDAY WILL HAVE THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS
WITH PASSING WEATHER SYSTEMS. MONDAY AND TUESDAY WILL BE DRIER AND
WARMER WITH A PASSING HIGH PRESSURE RIDGE. ALTHOUGH DAYTIME
HEATING AND RESIDUAL MOISTURE ARE LIKELY TO PRODUCE SCATTERED
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS BOTH DAYS...
MAINLY OVER AND NEAR THE MOUNTAINS. BY LATE IN THE WEEK...WETTER
AND COOLER CONDITIONS COULD RETURN WITH UPSLOPE FLOW AND A PASSING
PACIFIC STORM SYSTEM. TEMPERATURES THROUGH THE PERIOD WILL RANGE
FROM NEAR TO SLIGHTLY BELOW AVERAGE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NEEDED OVER NORTHEAST COLORADO THROUGH
THE AFTERNOON.

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 22, 6:08 PM MDTSpecial Weather StatementBOULincoln37 min
May 22, 7:37 PM MDTSpecial Weather StatementBOUCrowley38 min
May 23, 5:41 AM MDTFlash Flood WatchBOUAdams, Arapahoe, Elbert, Lincoln, Logan, Morgan and 4 more18 hr
May 23, 1:38 PM MDTAreal Flood AdvisoryBOUAdams, Broomfield, Denver, Jefferson2 hr
May 23, 2:36 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe24 min
May 23, 3:35 PM MDTFlash Flood WarningBOUMorgan3 hr

Nearby

Areal Flood Advisories in Colorado, 2015Every areal flood advisory in 2015

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.