Alert archive / Kentucky / Flash Flood Watches in 2011

Flash Flood Watch 4, NWS Paducah, KY

April 21, 201122 counties in Kentucky; 19 counties in Illinois; 11 counties in Missouri

NWS Paducah, KY issued this flash flood watch at Apr 21, 2011, 3:46 PM CDT for 22 counties in Kentucky; 19 counties in Illinois; 11 counties in Missouri. It took effect at Apr 22, 2011, 1:00 AM CDT. It was in force for 6 days.

The area

The counties it named.

The facts

Issued
Apr 21, 2011, 3:46 PM CDT (20:46 UTC)
In effect from
Apr 22, 2011, 1:00 AM CDT
Expired
Apr 27, 2011, 7:00 PM CDT
In force
6 days
Issued by
NWS Paducah, KY
Flood severity
None
All 52 counties

Alexander County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Daviess County, KY, Fulton County, KY, Graves County, KY, Henderson County, KY, Hickman County, KY, Hopkins County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McLean County, KY, Muhlenberg County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Carter County, MO, Mississippi County, MO, New Madrid County, MO, Perry County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO

The radar

The Paducah radar (KPAH), 31 km from the middle of the area, began a volume at 20:46 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

Nashville Metro, TN (KBNA), launched 12:00Z, 8.8 hours before the alert went out and 232 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, Nashville Metro, TN at 12:00Z on 2011-04-21Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2011-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 square meters per square second.19395878Sfc1 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
1190 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
172 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 watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Paducah, KY wrote its last area forecast discussion before this flash flood watch went out at Apr 21, 6:30 AM CDT, 9 hours 16 minutes earlier.

Area forecast discussion, Apr 21, 6:30 AM CDT, 9 hours 16 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
630 AM CDT THU APR 21 2011

.UPDATED...
FOR 12Z AVIATION ONLY.

.DISCUSSION...
A VERY ACTIVE WEATHER PATTERN IS SHAPING UP FOR AREAS FROM THE
SOUTHERN PLAINS AND RED RIVER VALLEY REGION OF OKLAHOMA...NORTHEAST
ACROSS THE OZARKS AND INTO THE MID MISSISSIPPI AND OHIO VALLEY
REGIONS. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ARE FORECAST
OVER THE NEXT SEVERAL DAYS...THAT OVER TIME COULD LEAD TO CONSIDERABLE
FLOOD CONCERNS...NOT ONLY IN AN AREAL SENSE...BUT LONGER TERM AS WELL
AND WITH RESPECT TO THE RIVERS. WE PLAN ON ISSUING A HYDROLOGIC
OUTLOOK THIS MORNING TO OUTLOOK AND DISCUSS OUR CONCERNS. LATER
SHIFTS MAY HAVE TO CONSIDER A FLOOD/FLASH FLOOD WATCH. THINK IT IS
A TAD TOO SOON TO PULL THE TRIGGER...GIVEN SOME MODEL DIFFERENCES
IN QPF PLACEMENT. THE MAIN DIFFERENCE THROUGH THE WEEKEND...IS THE
SREF/NAM ARE A BIT FARTHER SOUTH WITH HEAVIER QPF AXIS THAN THE
GFS/ECMWF SOLUTIONS. WE ARE TRENDING TOWARD THE GFS/ECMWF SOLUTIONS.

FOR TODAY...CONVECTION REMAINS FOCUSED TO OUR SOUTH. HIGH PRESSURE
WILL MOVE ACROSS THE GREAT LAKES REGION TODAY...WITH A QUASI STATIONARY
FRONT STILL SOUTH ACROSS THE GULF COAST REGION...KEEPING US COOL AND
IN AN EASTERLY FLOW PATTERN. LOWERED POPS MORE SO TODAY...AND KEPT
BEST VALUES OVER THE SW 1/2 OF THE AREA...PRIMARILY THIS AFTERNOON
FOR SHOWERS AND PERHAPS THUNDERSTORMS.

TONIGHT...THE BOUNDARY WILL LIFT NORTH AS A WARM FRONT AND ENTER INTO
THE REGION BY 12Z FRIDAY. EXPECT AN INCREASE IN SHOWERS AND STORMS
TONIGHT...AFFECTING MOST AREAS. THE BOUNDARY WILL CONTINUE TO PROGRESS
NORTH THROUGH THE DAY...CARRYING THE BEST CHANCE OF CONVECTION WITH
IT. ROUND 1 SHOULD NOT BE TOO PROBLEMATIC. OUR GRID QPF GENERALLY
RUNS FROM 0.50 TO 0.75 WEST KENTUCKY TO 1-1.5 INCHES FROM SOUTHERN
ILLINOIS INTO SOUTHWEST INDIANA.

FRIDAY NIGHT...FOCUS SHOULD SHIFT TO OUR WEST...WITH THE APPROACH OF
A COLD FRONTAL BOUNDARY. HAVE BEST CHANCE POPS NW 1/2 FRIDAY NIGHT
AND LOWER SE 1/4 OF THE AREA. CANNOT RULE OUT A FEW SEVERE STORMS
FRI/FRI NIGHT. LAPSE RATES ARE QUITE GOOD...RUNNING 7-8 C/KM. VERTICAL
SPEED SHEAR IS NOT THAT GREAT ABOVE H7 THOUGH...WHICH LEADS ME TO
BELIEVE MODE WILL BE MORE MULTI CELLULAR WITH SOME STRONG TO SEVERE
STORMS THAT MAY PRODUCE HAIL OR STRONG WIND GUSTS. HEAVY RAIN WILL
WITH TIME BECOME A GREATER CONCERN.

THE AFOREMENTIONED COLD FRONT IS FORECAST TO PUSH INTO THE CWFA BY
SUNDAY AND STALL. THUS...MORE SHOWER AND THUNDERSTORM ACTIVITY IS
IN THE WORKS. THE BOUNDARY WILL PUSH BACK AS A WARM FRONT SUNDAY NIGHT
THROUGH MONDAY. AS A RESULT WE MAY SEE A PULL BACK IN THE CONVECTIVE
ACTIVITY DURING THIS TIME FRAME AS WE ARE PUT BACK INTO THE WARM
SECTOR. ANOTHER FRONT WILL PUSH INTO THE REGION MONDAY NIGHT INTO
TUESDAY...AND BE THE FOCUS FOR MORE RAIN/STORMS.

FOR WHATEVER IT IS WORTH...OUR FAVORED BLEND OF THE GFS AND ECMWF
MODELS DEPICTS ANYWHERE FROM 4 TO 8 INCHES OF RAIN IS POSSIBLE ACROSS
THE CWFA THROUGH NEXT WEDNESDAY 12Z. THANKFULLY IT WILL BE SPREAD
OUT OVER SEVERAL EVENTS IN TERMS OF LOCAL SHORT-FUSE FLOOD CONCERNS.
BUT...HAVING SAID THAT...EACH EVENT WILL POTENTIALLY BE A RESPECTABLE
RAIN MAKER...WHICH OVER TIME...WILL ONLY LOWER FFG VALUES AND
INCREASE THE LIKELIHOOD OF FLOODING/FLASH FLOODING. IN THE LONG TERM
THERE MAY BE NOTABLE IMPACTS WITH RIVER FLOODING AS WELL. NO CHANGES
WERE MADE BEYOND MONDAY...IN THE LONG TERM PORTION OF THE FORECAST.

..NOLES..

&&

.AVIATION...
MAINLY VFR CONDITIONS EXPECTED THROUGH THE DAYLIGHT HOURS WITH SOME
MVFR CIGS EARLY THIS MORNING. WILL SLOWLY BRING IN MVFR CIGS AFTER
SUNSET. WILL TEMPO SOME PRECIP THIS EVENING. WILL BRING IN
PREDOMINANT MVFR TOWARD THE END OF THE VALID TIME OF THIS ISSUANCE
WILL INTRODUCE SOME IFR CIGS AND VSBY IN THE LAST LEG OF THIS
ISSUANCE IN ADDITION TO PREDOMINANT TSRA.

..KH..

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
MO...NONE.
IL...NONE.
IN...NONE.
&&
Hazardous weather outlook, Apr 21, 11:54 AM CDT, 3 hours 52 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 Paducah, KY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 10:48 AM CDTRiver Flood WarningPAHWayne, White25 hr

Nearby

Flash Flood Watches in Kentucky, 2011Flash Flood Watches in Illinois, 2011Flash Flood Watches in Missouri, 2011Every flash flood watch in 2011

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.