Alert archive / Alabama / Special Marine Warnings in 2021

Special Marine Warning 252, NWS Mobile, AL

August 14, 2021

NWS Mobile, AL issued this special marine warning at Aug 14, 2021, 4:46 PM CDT. It was in force for 56 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
Aug 14, 2021, 4:46 PM CDT (21:46 UTC)
Expired
Aug 14, 2021, 5:42 PM CDT
In force
56 min
Issued by
NWS Mobile, AL
Area
Storm-based polygon
Hail
0.0 in
Wind
34.0 mph

The radar

The Mobile radar (KMOB), 108 km from the middle of the area, began a volume at 21:50 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 12:00Z, 9.8 hours before the alert went out and 245 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 12:00Z on 2021-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 747 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 12:00Z on 2021-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 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
747 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
1022 m above ground
0-6 km bulk shear
1 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

588 
WHUS54 KMOB 142146
SMWMOB
GMZ634-142315-
/O.NEW.KMOB.MA.W.0252.210814T2146Z-210814T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mobile AL
446 PM CDT Sat Aug 14 2021

The National Weather Service in Mobile has issued a

* Special Marine Warning for...
  Pensacola Bay Area including Santa Rosa Sound...

* Until 615 PM CDT.

* At 446 PM CDT, a strong thunderstorm was located 7 nm north of
  Blackwater Bay Bridge, or 26 nm northwest of Mary Esther, moving
  south at 10 knots.

  HAZARD...Wind gusts 34 knots or greater.

  SOURCE...Radar.

  IMPACT...Small craft could be damaged in briefly higher winds and 
           suddenly higher waves.

* Locations impacted include...
  Pensacola Bay, West Santa Rosa Sound, Escambia Bay Bridge, East
  Bay, Escambia Bay, Pensacola Bay Bridge and Garcon Point Bridge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor immediately as gusty winds and high waves are
expected.

Frequent lightning is occurring with this storm. If caught on the
open water stay below deck if possible, keep away from ungrounded
metal objects.

&&

LAT...LON 3052 8711 3045 8710 3044 8710 3045 8707
      3058 8699 3041 8701 3036 8720 3035 8716
      3038 8701 3036 8702 3033 8731 3034 8727
      3034 8728 3035 8727 3037 8727 3036 8733
      3043 8717 3049 8715 3059 8721
TIME...MOT...LOC 2146Z 003DEG 12KT 3070 8703 

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

$$

MM
2 follow-up statements
056 
FZUS74 KMOB 142224
MWSMOB

Marine Weather Statement
National Weather Service Mobile AL
524 PM CDT Sat Aug 14 2021

GMZ634-142315-
/O.CON.KMOB.MA.W.0252.000000T0000Z-210814T2315Z/
524 PM CDT Sat Aug 14 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 615 PM CDT...

For the following areas...
Pensacola Bay Area including Santa Rosa Sound...

At 523 PM CDT, a strong thunderstorm was located over Blackwater Bay
Bridge, or 20 nm northeast of Pensacola Pass, moving south at 10
knots.

HAZARD...Wind gusts 34 knots or greater.

SOURCE...Radar indicated.

IMPACT...Small craft could be damaged in briefly higher winds and 
         suddenly higher waves.

Locations impacted include...
Pensacola Bay, West Santa Rosa Sound, Escambia Bay Bridge, East Bay,
Escambia Bay, Pensacola Bay Bridge and Garcon Point Bridge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor immediately as gusty winds and high waves are
expected.

Frequent lightning is occurring with this storm. If caught on the
open water stay below deck if possible, keep away from ungrounded
metal objects.

&&

LAT...LON 3052 8711 3045 8710 3044 8710 3045 8707
      3058 8699 3041 8701 3036 8720 3035 8716
      3038 8701 3036 8702 3033 8731 3034 8727
      3034 8728 3035 8727 3037 8727 3036 8733
      3043 8717 3049 8715 3059 8721
TIME...MOT...LOC 2223Z 003DEG 12KT 3057 8704 

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

$$

MM
076 
FZUS74 KMOB 142242
MWSMOB

Marine Weather Statement
National Weather Service Mobile AL
542 PM CDT Sat Aug 14 2021

GMZ634-142251-
/O.CAN.KMOB.MA.W.0252.000000T0000Z-210814T2315Z/
542 PM CDT Sat Aug 14 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

The affected areas were... 
Pensacola Bay Area including Santa Rosa Sound...

The thunderstorm has weakened and no longer poses a significant
threat to boaters.

LAT...LON 3052 8711 3045 8710 3044 8710 3045 8707
      3058 8699 3041 8701 3036 8720 3035 8716
      3038 8701 3036 8702 3033 8731 3034 8727
      3034 8728 3035 8727 3037 8727 3036 8733
      3043 8717 3049 8715 3059 8721
TIME...MOT...LOC 2238Z 003DEG 12KT 3051 8704 

$$

MM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 1:02 PM CDTRip Current StatementMOBBaldwin, Mobile4 days
Aug 14, 1:02 PM CDTHigh Surf AdvisoryMOBBaldwin, Mobile57 hr
Aug 14, 2:16 PM CDTSpecial Weather StatementMOBBaldwin44 min
Aug 14, 3:14 PM CDTSpecial Weather StatementMOBMobile46 min
Aug 14, 4:13 PM CDTTropical Storm WatchMOBCovington, Escambia30 hr
Aug 14, 4:41 PM CDTSpecial Marine WarningMOB94 min
Aug 14, 5:52 PM CDTSpecial Marine WarningMOB83 min
Aug 14, 6:28 PM CDTSpecial Weather StatementMOBButler47 min
Aug 14, 4:01 PM CDTSpecial Weather StatementMOBOkaloosa, Santa Rosa59 min
Aug 14, 4:18 PM CDTSpecial Weather StatementMOBEscambia57 min
Aug 14, 4:33 PM CDTSevere Thunderstorm WarningMOBEscambia, Santa Rosa42 min
Aug 14, 4:39 PM CDTSpecial Weather StatementMOBOkaloosa66 min
Aug 14, 4:49 PM CDTSpecial Weather StatementMOBEscambia56 min
Aug 14, 5:10 PM CDTAreal Flood AdvisoryMOBSanta Rosa3 hr

Nearby

Special Marine Warnings in Alabama, 2021Every special marine warning in 2021

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.