Alert archive / Florida / Mesoscale Discussions in 2021

Mesoscale Discussion 145

March 3, 2021Citrus County, Hernando County, Pasco County, Florida

The Storm Prediction Center issued this mesoscale discussion at Mar 3, 2021, 2:47 AM EST for Citrus County, Hernando County, Pasco County, Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 3, 2021, 2:47 AM EST (07:47 UTC)
Expired: Mar 3, 2021, 5:15 AM EST
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

Counties Citrus County, FL, Hernando County, FL, Pasco County, FL

The radar

The Tampa radar (KTBW), 113 km from the middle of the area, began a volume at 07:50 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

Tampa Bay, FL (KTBW), launched 00:00Z, 7.8 hours before the alert went out and 113 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: 1 J/kg
Mixed-layer CIN: -90 J/kg
Mixed-layer LCL: 1579 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 56 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

945 
ACUS11 KWNS 030747
SWOMCD
SPC MCD 030747 
FLZ000-031015-

Mesoscale Discussion 0145
NWS Storm Prediction Center Norman OK
0147 AM CST Wed Mar 03 2021

Areas affected...the western coast of Florida north of Tampa Bay

Concerning...Severe potential...Watch unlikely 

Valid 030747Z - 031015Z

Probability of Watch Issuance...5 percent

SUMMARY...A line of storms will continue to affect the region from
north to south through early morning, and a few strong wind gusts
cannot be ruled out.

DISCUSSION...A line of thunderstorms persists along a cold front,
with northern end now into Levy County and the bulk of the line over
the Gulf of Mexico. Surface analysis shows relatively cool and
stable air over northern FL, with only lower 60s F dewpoints. The
more unstable air currently resides farther south near TBW with
dewpoints to 70 F.

As a shortwave trough grazes northern FL, southwest winds above the
surface will maintain gradual warm/moist advection. Currently,
modest pressure falls are noted with up to 1 mb/hr. As this
continues ahead of the line, some airmass recovery is expected along
the coast, with mid to upper 60s F dewpoints by about 09-10Z.

Even so, modified forecast soundings show poor lapse rates aloft,
and minimal instability. The most favorable aspect will be strong
westerlies aloft and strong deep-layer shear, aiding storm longevity
and perhaps aiding in downward momentum transfer for a few strong
gusts.

..Jewell/Edwards.. 03/03/2021

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   29218296 29268256 29018225 28618218 28328238 28118263
            28028291 28358283 28638277 28898280 29218296

Nearby

Mesoscale Discussions in Florida, 2021 Every mesoscale discussion 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.