Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 2021

September 16, 200933 counties in Alabama; Okaloosa County, Florida; Quitman County, Georgia

The Storm Prediction Center issued this mesoscale discussion at Sep 16, 2009, 12:13 PM CDT for 33 counties in Alabama; Okaloosa County, Florida; Quitman County, Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 16, 2009, 12:13 PM CDT (17:13 UTC)
Expired
Sep 16, 2009, 2:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 35 counties

Autauga County, AL, Barbour County, AL, Bibb County, AL, Bullock County, AL, Butler County, AL, Chambers County, AL, Chilton County, AL, Clarke County, AL, Clay County, AL, Coffee County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Geneva County, AL, Hale County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pike County, AL, Russell County, AL, Shelby County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Wilcox County, AL, Okaloosa County, FL, Quitman County, GA

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 5.2 hours before the alert went out and 110 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, Birmingham, AL at 12:00Z on 2009-09-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1274 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2009-09-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 square meters per square second.193958Sfc1 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
1274 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
460 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
ACUS11 KWNS 161713
SWOMCD
SPC MCD 161713 
GAZ000-ALZ000-FLZ000-161915-

MESOSCALE DISCUSSION 2021
NWS STORM PREDICTION CENTER NORMAN OK
1213 PM CDT WED SEP 16 2009

AREAS AFFECTED...CENTRAL/SOUTHERN AL AND FL PANHANDLE

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 161713Z - 161915Z

POTENTIAL FOR A BRIEF/ISOLATED TORNADO OR TWO...AND WIND
DAMAGE...MAY MODESTLY INCREASE THROUGH THE AFTERNOON MAINLY ACROSS
PORTIONS OF CENTRAL/SOUTHERN AL. ISOLATED/MARGINAL NATURE OF THE
RISK SHOULD PRECLUDE A WATCH ISSUANCE...BUT DEVELOPMENTAL TRENDS
WILL CONTINUE TO BE MONITORED.

AS THE PARENT CYCLONE REMAINS OVER THE ARKLATEX VICINITY...AN
INCREASE IN SHOWERS/TSTMS APPEARS TO BE TIED TO A SUBTROPICAL/MID
LEVEL DISTURBANCE CROSSING THE CENTRAL GULF AND ADJACENT GULF COAST
STATES...ALONG WITH A VERY MOIST/WEAKLY CAPPED BOUNDARY LAYER. AS
HAS BEEN THE CASE FOR THE PAST FEW DAYS...WEAK DEEP LAYER FLOW/POOR
MID LEVEL LAPSE RATES WILL REMAIN LIMITING FACTORS FOR A MORE
APPRECIABLE SEVERE RISK. NONETHELESS...THE COMBINATION OF AMPLE
SURFACE HEATING /LOWER 80S F/ AND LOWER TO MIDDLE 70S F
DEWPOINTS...ALONG WITH MODESTLY BACKED /SOUTHEASTERLY/ LOW LEVEL
FLOW ESPECIALLY ACROSS CENTRAL/SOUTHERN AL WITH 0-1 KM SRH TO AROUND
100 MS/S2...MAY BE SUFFICIENT FOR ISOLATED/BRIEF TORNADOES AND/OR
WIND DAMAGE.

..GUYER.. 09/16/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FFC...TAE...BMX...MOB...

LAT...LON   33328553 31968484 30508643 31038808 33428771 33328553

Nearby

Mesoscale Discussions in Alabama, 2009Mesoscale Discussions in Florida, 2009Mesoscale Discussions in Georgia, 2009Every mesoscale discussion 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.