Alert archive / Alabama / Special Marine Warnings in 2017

Special Marine Warning 252, NWS Mobile, AL

July 20, 2017

NWS Mobile, AL issued this special marine warning at Jul 20, 2017, 6:10 AM CDT. It was in force for 65 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 20, 2017, 6:10 AM CDT (11:10 UTC)
Expired
Jul 20, 2017, 7:15 AM CDT
In force
65 min
Issued by
NWS Mobile, AL
Area
Storm-based polygon
Hail
0.0 in
Wind
34.0 mph

The radar

The Mobile radar (KMOB), 74 km from the middle of the area, began a volume at 11:09 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

Slidell Radar S, LA (KSIL), launched 00:00Z, 11.2 hours before the alert went out and 147 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, Slidell Radar S, LA at 00:00Z on 2017-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2374 joules per kilogram.LCLLFCEL10008507005003002001001 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, Slidell Radar S, LA at 00:00Z on 2017-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.1939Sfc1 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
2374 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
1086 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
26 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

246 
WHUS54 KMOB 201110
SMWMOB
GMZ650-201215-
/O.NEW.KMOB.MA.W.0252.170720T1110Z-170720T1215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SPECIAL MARINE WARNING
NATIONAL WEATHER SERVICE MOBILE AL
610 AM CDT THU JUL 20 2017

THE NATIONAL WEATHER SERVICE IN MOBILE HAS ISSUED A

* SPECIAL MARINE WARNING FOR...
  COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20 NM...

* UNTIL 715 AM CDT

* AT 610 AM CDT...A STRONG THUNDERSTORM WAS LOCATED NEAR FAREWELL
  BUOY...MOVING WEST AT 10 KNOTS.

  HAZARD...WIND GUSTS 34 KNOTS OR GREATER. 

  SOURCE...RADAR INDICATED. 

  IMPACT...EXPECT WIND GUSTS IN EXCESS OF 34 KNOTS...SUDDENLY HIGHER 
           WAVES...FREQUENT LIGHTNING...AND HEAVY DOWNPOURS. MAKE 
           SURE ALL ON BOARD ARE WEARING LIFE JACKETS. 

* LOCATIONS IMPACTED INCLUDE...
  FAREWELL BUOY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO SAFE HARBOR IMMEDIATELY AS GUSTY WINDS AND HIGH WAVES ARE
EXPECTED.

&&

LAT...LON 3021 8810 3001 8798 2989 8823 2990 8824
      2990 8825 2988 8831 3012 8836
TIME...MOT...LOC 1110Z 069DEG 12KT 3006 8816 

HAIL...0.00IN
WIND...>34KTS

$$
1 follow-up statement
121 
FZUS74 KMOB 201206
MWSMOB

MARINE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOBILE AL
706 AM CDT THU JUL 20 2017

GMZ650-201215-
/O.EXP.KMOB.MA.W.0252.000000T0000Z-170720T1215Z/
706 AM CDT THU JUL 20 2017

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 715 AM CDT...

THE AFFECTED AREAS WERE... 
COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20 NM...

THE THUNDERSTORM HAS WEAKENED THUS THE WARNING HAS BEEN CANCELLED.

LAT...LON 3021 8810 3001 8798 2989 8823 2990 8824
      2990 8825 2988 8831 3012 8836
TIME...MOT...LOC 1205Z 069DEG 12KT 2999 8836 

$$

The office that day

Everything else NWS Mobile, AL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 5:23 PM CDTSpecial Marine WarningMOB67 min

Nearby

Special Marine Warnings in Alabama, 2017Every special marine warning in 2017

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.