Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 85

February 3, 201117 counties in Alabama

The Storm Prediction Center issued this mesoscale discussion at Feb 3, 2011, 2:00 PM CST for 17 counties in Alabama. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Feb 3, 2011, 2:00 PM CST (20:00 UTC)
Expired: Feb 3, 2011, 5:30 PM CST
In force: 4 hr
Issued by: the Storm Prediction Center

Counties Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Clay County, AL, Cleburne County, AL, Cullman County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Marshall County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL

The radar

The Birmingham radar (KBMX), 47 km from the middle of the area, began a volume at 20:03 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

Birmingham, AL (KBMX), launched 12:00Z, 8.0 hours before the alert went out and 46 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1803 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: -64 m²/s²
0-3 km storm-relative helicity: 98 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.

476 
ACUS11 KWNS 032000
SWOMCD
SPC MCD 032000 
ALZ000-032330-

MESOSCALE DISCUSSION 0085
NWS STORM PREDICTION CENTER NORMAN OK
0200 PM CST THU FEB 03 2011

AREAS AFFECTED...PORTIONS OF CNTRL/NRN AL

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 032000Z - 032330Z

A MIX OF SLEET AND FREEZING RAIN WILL TRANSLATE E-NEWD ACROSS
PORTIONS OF CNTRL/NRN AL THROUGH LATE AFTERNOON. FREEZING RAIN RATES
AOA 0.10 INCH PER 3 HRS WILL BE POSSIBLE.

THE PRECIPITATION WILL OCCUR IN RESPONSE TO WAA/ISENTROPIC UPGLIDE
IN THE LOW/MID LEVELS. PRECIP RATES ARE EXPECTED TO INTENSIFY AS LOW
LEVELS CONTINUE APPROACHING SATURATION IN RESPONSE TO ONGOING
PRECIP. WITH SURFACE WET-BULB TEMPERATURES CURRENTLY BELOW
FREEZING...A MIX OF PRECIP TYPES WILL OCCUR. FORECAST SOUNDINGS FROM
THE RUC INDICATE THAT BOTH SLEET AND FREEZING RAIN WILL BE POSSIBLE
ACROSS THE DISCUSSION AREA...WITH ELEVATED WARM LAYER TEMPERATURES
GENERALLY IN THE 2-3C RANGE. WHERE FREEZING RAIN OCCURS...RATES AOA
0.10 INCH PER 3 HOURS WILL BE POSSIBLE...ESPECIALLY IN ASSOCIATION
WITH THE BAND OF MDT PRECIP THAT CURRENTLY EXTENDS FROM NEAR TCL TO
35 N LGC. AS THE BOUNDARY-LAYER FLOW GRADUALLY ATTAINS MORE OF AN
ELY COMPONENT...THE WET-BULB ZERO LINE AT THE SFC WILL BE NUDGED
WWD. THIS WILL CAUSE THE PRECIP TO CHANGE OVER TO RAIN FROM E TO W
LATER THIS AFTERNOON ACROSS PORTIONS OF ERN AL.

..COHEN/PETERS.. 02/03/2011

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

ATTN...WFO...BMX...HUN...

LAT...LON   33828807 34438660 34318561 33498531 33028572 32908683
            32998822 33828807

Nearby

Mesoscale Discussions in Alabama, 2011 Every mesoscale discussion 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.