Alert archive / Florida / Mesoscale Discussions in 2011

Mesoscale Discussion 26

January 17, 2011Broward County, Miami-Dade County, Monroe County, Florida

The Storm Prediction Center issued this mesoscale discussion at Jan 17, 2011, 3:23 PM EST for Broward County, Miami-Dade County, Monroe County, Florida. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Jan 17, 2011, 3:23 PM EST (20:23 UTC)
Expired
Jan 17, 2011, 5:00 PM EST
In force
97 min
Issued by
the Storm Prediction Center

Counties Broward County, FL, Miami-Dade County, FL, Monroe County, FL

The radar

The Miami radar (KAMX), 87 km from the middle of the area, began a volume at 20:23 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

Key West, FL (KEYW), launched 12:00Z, 8.4 hours before the alert went out and 95 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, Key West, FL at 12:00Z on 2011-01-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 672 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Key West, FL at 12:00Z on 2011-01-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 134 square meters per square second.1939587897Sfc1 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
672 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
502 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
134 m²/s²
0-3 km storm-relative helicity
156 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

793 
ACUS11 KWNS 172024
SWOMCD
SPC MCD 172023
FLZ000-172200-

MESOSCALE DISCUSSION 0026
NWS STORM PREDICTION CENTER NORMAN OK
0223 PM CST MON JAN 17 2011

AREAS AFFECTED...SRN FL

CONCERNING...TORNADO WATCH 5...6...

VALID 172023Z - 172200Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 5...6...CONTINUES.

NRN ZONE OF STORMS FROM TPA TO MLB HAS WEAKENED AS THE INFLUENCE OF
THE UPPER SHORTWAVE TO THE N HAS WANED AND STORM ARE NO LONGER BEING
GENERATED UPSTREAM ALONG THE BOUNDARY. WITH CLOUDS AND RAIN
OVERSPREADING MUCH OF THE AREA...FURTHER DESTABILIZATION IS UNLIKELY


FARTHER S...WIDESPREAD RAIN AND EMBEDDED STORMS HAVE ALSO OVERSPREAD
FAR SRN FL...WITH A FEW CELLS SHOWING ROTATION OFF THE SERN COAST.
SURFACE ANALYSIS...AS WELL AS AN 18Z KEY SOUNDING...SHOWS A
MODERATELY UNSTABLE AIR MASS WITH DEWPOINTS RISING TO AROUND 70 F.
ALTHOUGH WIND ALOFT ARE VEERING...ADDITIONAL ACTIVITY IS INCREASING
IN INTENSITY W OF THE KEYS. THESE STORMS WILL LIKELY CONTAIN STRONG
AND POSSIBLY DAMAGING WIND GUSTS AS THEY AFFECT THE FL KEYS AND
EVENTUALLY THE SRN PENINSULA. THE TORNADO THREAT APPEARS TO BE
LESSENING WITH TIME AS HODOGRAPHS BECOME STRAIGHT...BUT INCREASING
WIND FIELDS ALOFT COULD COMBINE WITH ORGANIZED LINES/BOWS TO PRODUCE
WIND DAMAGE.

..JEWELL.. 01/17/2011

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

ATTN...WFO...MFL...KEY...

LAT...LON   25858179 26418000 25528012 25028034 24518121 24418193
            24688184 24888140 25078124 25368125 25648138 25858179

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 17, 10:17 AM ESTMesoscale DiscussionSPCBrevard, Broward, Charlotte, Collier, DeSoto, Glades and 15 more118 min
Jan 17, 11:33 AM ESTTornado WatchSPCBroward, Miami-Dade, Monroe, Palm Beach7 hr
Jan 17, 11:54 AM ESTTornado WatchSPCBrevard, Charlotte, DeSoto, Hardee, Highlands, Indian River and 9 more5 hr
Jan 17, 6:27 PM ESTMesoscale DiscussionSPCMiami-Dade63 min

Nearby

Mesoscale Discussions in Florida, 2011Every 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.