Alert archive / Alabama / Frost Advisories in 2011

Frost Advisory 2, NWS Mobile, AL

October 21, 20118 counties in Alabama; Greene County, Perry County, Wayne County, Mississippi

NWS Mobile, AL issued this frost advisory at Oct 21, 2011, 2:15 PM CDT for 8 counties in Alabama; Greene County, Perry County, Wayne County, Mississippi. It took effect at Oct 22, 2011, 2:00 AM CDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Oct 21, 2011, 2:15 PM CDT (19:15 UTC)
In effect from
Oct 22, 2011, 2:00 AM CDT
Expired
Oct 22, 2011, 8:00 AM CDT
In force
6 hr
Issued by
NWS Mobile, AL

Counties Butler County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Crenshaw County, AL, Monroe County, AL, Washington County, AL, Wilcox County, AL, Greene County, MS, Perry County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 112 km from the middle of the area, began a volume at 19:16 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, 7.3 hours before the alert went out and 198 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 2011-10-21Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2011-10-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1290 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
113 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.

583 
WWUS74 KMOB 211915
NPWMOB

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE MOBILE AL
215 PM CDT FRI OCT 21 2011

...PATCHY FROST EXPECTED OVER INTERIOR SOUTHEAST MISSISSIPPI AND
SOUTHWEST ALABAMA LATE TONIGHT...

.AN UNSEASONABLY COLD AIRMASS CONTINUES OVER THE AREA THROUGH TONIGHT
...AND WHEN COMBINED WITH LIGHT WINDS...WILL ALLOW TEMPERATURES TO
AGAIN FALL INTO THE THIRTIES OVER MOST OF THE REGION. TEMPERATURES
ARE EXPECTED TO FALL LOW ENOUGH FOR FROST TO FORM ALONG AND NORTH OF
A LINE FROM NEW AUGUSTA...MISSISSIPPI TO LUVERNE...ALABAMA.

ALZ051>058-MSZ067-075-076-220315-
/O.NEW.KMOB.FR.Y.0002.111022T0700Z-111022T1300Z/
CHOCTAW-WASHINGTON-CLARKE-WILCOX-MONROE-CONECUH-BUTLER-CRENSHAW-
WAYNE-PERRY-GREENE-
INCLUDING THE CITIES OF...BUTLER...LISMAN...SILAS...CHATOM...
MILLRY...JACKSON...THOMASVILLE...GROVE HILL...CAMDEN...
PINE HILL...HOMEWOOD...MONROEVILLE...GREENVILLE...LUVERNE...
BRANTLEY...WAYNESBORO...RICHTON...BEAUMONT...NEW AUGUSTA...MCLAIN
215 PM CDT FRI OCT 21 2011

...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM CDT SATURDAY...

THE NATIONAL WEATHER SERVICE IN MOBILE HAS ISSUED A FROST
ADVISORY...WHICH IS IN EFFECT FROM 2 AM TO 8 AM CDT SATURDAY. 

* EVENT...PATCHY FROST OVER INLAND AREAS GENERALLY NORTH OF A 
  LINE FROM NEW AUGUSTA MISSISSIPPI TO EVERGREEN ALABAMA TO 
  LUVERNE ALABAMA. 

* TIMING...PATCHY FROST DEVELOPS AFTER 4 AM AND DISSIPATES SHORTLY
  AFTER SUNRISE SATURDAY.

* IMPACT...PATCHY FROST WILL AGAIN BE A PROBLEM FOR SENSITIVE PLANTS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FROST ADVISORY MEANS THAT FROST IS POSSIBLE. SENSITIVE OUTDOOR
PLANTS MAY BE KILLED OR SUFFER FROST BURN IF LEFT UNCOVERED.

&&

$$
1 follow-up statement
347 
WWUS74 KMOB 220254
NPWMOB

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE MOBILE AL
954 PM CDT FRI OCT 21 2011

...PATCHY FROST EXPECTED OVER INTERIOR SOUTHEAST MISSISSIPPI AND
SOUTHWEST ALABAMA LATE TONIGHT...

.AN UNSEASONABLY COLD AIRMASS WILL CONTINUE OVER THE AREA THROUGH
TONIGHT ...AND WHEN COMBINED WITH LIGHT WINDS...WILL ALLOW TEMPERATURES
TO AGAIN FALL INTO THE MID TO UPPER 30S OVER MOST OF THE ADVISED
AREA. TEMPERATURES AT A FEW LOCATIONS WILL POSSIBLY DROP INTO THE
LOWER 30S. TEMPERATURES ARE EXPECTED TO FALL LOW ENOUGH FOR FROST TO
FORM ALONG AND NORTH OF A LINE FROM NEAR NEW AUGUSTA MISSISSIPPI TO
NEAR LUVERNE ALABAMA.

ALZ051>058-MSZ067-075-076-221300-
/O.CON.KMOB.FR.Y.0002.111022T0700Z-111022T1300Z/
CHOCTAW-WASHINGTON-CLARKE-WILCOX-MONROE-CONECUH-BUTLER-CRENSHAW-
WAYNE-PERRY-GREENE-
INCLUDING THE CITIES OF...BUTLER...LISMAN...SILAS...CHATOM...
MILLRY...JACKSON...THOMASVILLE...GROVE HILL...CAMDEN...
PINE HILL...HOMEWOOD...MONROEVILLE...GREENVILLE...LUVERNE...
BRANTLEY...WAYNESBORO...RICHTON...BEAUMONT...NEW AUGUSTA...MCLAIN
954 PM CDT FRI OCT 21 2011

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 8 AM CDT
SATURDAY...

* EVENT...PATCHY FROST OVER INLAND AREAS GENERALLY NORTH OF A 
  LINE FROM NEW AUGUSTA MISSISSIPPI TO EVERGREEN ALABAMA TO 
  LUVERNE ALABAMA. 

* TIMING...PATCHY FROST WILL DEVELOP AFTER 4 AM AND SHOULD DISSIPATE
  SHORTLY AFTER SUNRISE SATURDAY MORNING.

* IMPACT...THE PATCHY FROST WILL BE A PROBLEM FOR SENSITIVE PLANTS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FROST ADVISORY MEANS THAT FROST IS POSSIBLE. SENSITIVE OUTDOOR
PLANTS MAY BE KILLED OR SUFFER FROST BURN IF LEFT UNCOVERED.

&&

$$

Nearby

Frost Advisories in Alabama, 2011Frost Advisories in Mississippi, 2011Every frost advisory 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.