Alert archive / Kentucky / Flash Flood Warnings in 2009

Flash Flood Warning 52, NWS Paducah, KY

September 2, 2009Lyon County, Kentucky

NWS Paducah, KY issued this flash flood warning at Sep 2, 2009, 11:50 PM CDT for Lyon County, Kentucky. It was in force for 89 min. 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 2, 2009, 11:50 PM CDT (04:50 UTC)
Expired: Sep 3, 2009, 1:19 AM CDT
In force: 89 min
Issued by: NWS Paducah, KY
Area: Storm-based polygon
Flood severity: None

County Lyon County, KY

The radar

The Paducah radar (KPAH), 61 km from the middle of the area, began a volume at 04:53 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 00:00Z, 4.8 hours before the alert went out and 165 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: 613 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 861 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 81 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 Paducah, KY wrote its last area forecast discussion before this flash flood warning went out at Sep 2, 9:23 PM CDT, 2 hours 27 minutes earlier.

Area forecast discussion, Sep 2, 9:23 PM CDT, 2 hours 27 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PADUCAH KY
923 PM CDT WED SEP 2 2009

.UPDATE...
FIRST PERIOD /TONIGHT/ UPDATE FOR SENSIBLE WEATHER TRENDS FOR THE
REMAINDER OF THE NIGHT.

&&

.DISCUSSION...
MESOSCALE VORTICITY CENTER /MVC/ LOCATED NEAR RANDOLPH COUNTY IL
/WEST OF CHESTER IL/ AROUND 00Z THURSDAY /7PM CDT WEDNESDAY/ IS
EVIDENT IN GOES WATER VAPOR/INFARED IMAGERY AND DIFFERENCE
CHANNELS THIS EVENING...WITH GOES IMAGERY SOUNDER DATA SHOWING A
PLUME OF PRECIPITABLE WATER VALUES BETWEEN 1.25-1.75 INCHES AND
LIFTED INDEX VALUES BETWEEN ZERO AND -3 DEGREES CELCIUS. THE
TAMDAR SOUNDING AT KPAH AROUND 22Z SUGGESTS THAT ANY PARCELS
SHOULD CONTINUE TO MOVE UPWARD INCREASING CLOSER TO A MOIST
ADIABATIC LAPSE RATE OVERNIGHT.

THE MVC SHOULD SHOULD CONTINUE TO ROTATE SEWD TONIGHT...LIFTING
THE MOIST LAYER AHEAD OF IT AND SUPPORTING ISOLATED UPDRAFTS
ENOUGH FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS...ESPECIALLY THIS EVENING. GIVEN ISOLATED HEAVY
PRECIPITATION REPORTS FROM S CENTRAL KY EARLY THIS
AFTERNOON...PRECIPITATION EFFICIENCY SHOULD REMAIN HIGH...WITH
HOURLY RAINFALL AMOUNTS IN EXCESS OF AN INCH LIKELY WITH ISOLATED
THUNDERSTORMS AND SHOWERS WITH HEAVY RAIN.

WITH THE INDUCED LOW LEVEL AGEOSTROPHIC FLOW/CONVERGENCE AND MID
LEVEL INSTABILITY AHEAD OF THIS SMALL WEATHER DISTURBANCE...I
CANNOT ELIMINATE PERIODIC CHANCES OF SHOWERS OVERNIGHT. THE
SURFACE WIND FLOW WILL STILL REMAIN WEAK IN THE VICINITY OF THE
RAIN AND SURFACE SATURATION WILL OCCUR QUICKLY...SO ADDED A
VARIABLE COVERAGE OF FOG TO THE FORECAST PACKAGE OVERNIGHT AS
WELL. THE OCCURENCE OF DENSE FOG WILL BE TOO SPOTTY/RANDOM/ TO
WARRANT A MENTION AT THIS TIME.

WITH THIS WEATHER FEATURE...ADJUSTED THE COVERAGE OF OPAQUE CLOUD
COVER AND MODIFIED THE TEMPERATURE/DEWPOINT VALUES TO ACCOUNT FOR
THIS OVERNIGHT WEATHER SYSTEM.

I AM NOT TOO CONFIDENT ABOUT THE 10 AM TO 1 PM CDT TIME PERIOD ON
THURSDAY FOR POP/WEATHER CHANCES...BUT BELIEVE THERE WILL BE A
TRANSITION PERIOD FOR LINGERING PRECIPITATION AND FOG AROUND
DAYBREAK...AS THE MVC MOVES EAST OF THE AREA.

&&

.AVIATION...
/EDITED FROM 216 PM CDT WED SEP 2 2009 ISSUANCE/
VFR CEILINGS EXPECTED TONIGHT AS MOISTURE MOVES IN FROM THE
SOUTHEAST. THIS MOISTURE MAY PRODUCE ISOLATED SHOWERS AND
THUNDERSTORMS OVER MAINLY WEST KENTUCKY. ANY PRECIPITATION SHOULD
DIMINISH EARLY THIS EVENING. MVFR FOG LIKELY AT MOST TAF SITES
WITH KCGI DOWN INTO THE IFR CATEGORY IN FOG. LIGHT WINDS EXPECTED
AT ALL SITES.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
MO...NONE.
IL...NONE.
IN...NONE.
&&

SMITH

Hazardous weather outlook, Sep 2, 9:34 PM CDT, 2 hours 16 minutes before

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In the hours before

Local storm report, Sep 2, 10:56 PM CDT, 54 minutes before

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The office that day

Everything else NWS Paducah, KY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 2, 10:34 PM CDT	Areal Flood Advisory	PAH	McCracken	56 min
Sep 2, 10:59 PM CDT	Areal Flood Advisory	PAH	Livingston, Lyon, Marshall	106 min
Sep 3, 12:36 AM CDT	Flash Flood Warning	PAH	Caldwell, Lyon, Trigg	95 min
Sep 3, 5:05 PM CDT	Areal Flood Advisory	PAH	Jefferson	55 min

Nearby

Flash Flood Warnings in Kentucky, 2009 Every flash flood warning in 2009

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.