Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 1798

August 22, 20128 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Aug 22, 2012, 12:56 PM EDT for 8 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 22, 2012, 12:56 PM EDT (16:56 UTC)
Expired: Aug 22, 2012, 3:00 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Brevard County, FL, Flagler County, FL, Lake County, FL, Orange County, FL, Osceola County, FL, Polk County, FL, Seminole County, FL, Volusia County, FL

The radar

The Melbourne radar (KMLB), 108 km from the middle of the area, began a volume at 16:57 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

Cape Canaveral, FL (KXMR), launched 12:00Z, 4.9 hours before the alert went out and 103 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: 115 J/kg
Mixed-layer CIN: -130 J/kg
Mixed-layer LCL: 1117 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 66 m²/s²
0-3 km storm-relative helicity: 88 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.

939 
ACUS11 KWNS 221657
SWOMCD
SPC MCD 221656
FLZ000-221900-

MESOSCALE DISCUSSION 1798
NWS STORM PREDICTION CENTER NORMAN OK
1156 AM CDT WED AUG 22 2012

AREAS AFFECTED...NORTH-CENTRAL FL PENINSULA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 221656Z - 221900Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...LOCALLY DAMAGING WINDS MAY BE POSSIBLE ACROSS
NORTH-CENTRAL PORTIONS OF THE FL PENINSULA THIS AFTERNOON...ALTHOUGH
THE ANTICIPATED ISOLATED/MARGINAL NATURE OF THE RISK WILL LIKELY
PRECLUDE A WATCH ISSUANCE.

DISCUSSION...THE LEADING EDGE OF A SLOW-MOVING/QUASI-ORGANIZED TSTM
COMPLEX CONTINUES TO PROGRESS EASTWARD ACROSS THE NORTH-CENTRAL FL
PENINSULA EARLY THIS AFTERNOON...WITH THE LEADING EDGE OF THE
COMPLEX/ASSOCIATED COLD POOL NEAR AND PARALLEL TO THE I-75 CORRIDOR
AS OF 1645Z...INCLUDING THE OCALA VICINITY TO NEAR/NORTHEAST OF THE
TAMPA-ST PETERBURG AREAS. WITH AMPLE INSOLATION AND A MOIST AIRMASS
/GENERALLY LOWER 70S F SURFACE DEWPOINTS/ AHEAD OF THESE
STORMS...INHIBITION CONTINUES TO STEADILY ERODE COINCIDENT WITH
MODERATE DESTABILIZATION /1000-2000 J PER KG MLCAPE/...ESPECIALLY
GIVEN THAT MID-LEVEL TEMPERATURES HAVE CONTINUED TO COOL OVER THE
PAST 24 HR PER 12Z OBSERVED SOUNDINGS. WITH A CONTINUED SLOW
EASTWARD PROGRESSION OF THE EXISTING TSTM COMPLEX EXPECTED...SOME
INTENSIFICATION OF THE CONVECTIVE LINE AND/OR NEW DEVELOPING
PERIPHERAL TSTMS SEEMS PROBABLE THIS AFTERNOON...WITH THE EAST COAST
SEA BREEZE AN ADDITIONAL FACTOR FOR INTENSIFICATION. LOCALIZED WIND
DAMAGE VIA WET MICROBURSTS WILL BE THE PRIMARY HAZARD.

..GUYER/MEAD.. 08/22/2012

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

ATTN...WFO...MLB...TBW...JAX...

LAT...LON   29458213 29648157 29318099 29148079 28348052 27678062
            27658200 27878239 28288189 28988173 29458213

Nearby

Mesoscale Discussions in Florida, 2012 Every mesoscale discussion in 2012

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.