Mesoscale Discussion 415

Issued

Apr 3, 2017, 3:59 AM CDT (08:59 UTC)

Expired

Apr 3, 2017, 6:00 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

The Mobile radar (KMOB), 23 km from the middle of the area, began a volume at 09:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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• Severe Thunderstorm Watch 115Apr 3, 4:25 AM CDT
• Tornado Watch 116Apr 3, 7:05 AM CDT

045 
ACUS11 KWNS 030859
SWOMCD
SPC MCD 030859 
ALZ000-FLZ000-MSZ000-LAZ000-031100-

Mesoscale Discussion 0415
NWS Storm Prediction Center Norman OK
0359 AM CDT Mon Apr 03 2017

Areas affected...East-central to southern MS...southeast LA...and
southwest to central AL

Concerning...Tornado Watch 114...

Valid 030859Z - 031100Z

The severe weather threat for Tornado Watch 114 continues.

SUMMARY...Storms capable of producing damaging winds and a tornado
threat continue to advance east across WW 114 in southeast LA and
southern to east-central MS.  The bands of storms, bowing at times,
will advance into southwest and central AL early this morning, with
central portions of AL expected to be affected prior to the Mobile
metro area.  A new WW is being considered for parts of central AL.

DISCUSSION...Trends in mosaic radar imagery showed a quasi-linear
MCS advancing steadily toward the east early this morning, while
40-45 kt southerly low-level jet maintains an influx of moisture
northward in advance of the QLCS across WW 114 and in AL.  This is
resulting in destabilization into central AL.  Although weak
instability at this time in that area, strong bulk shear and an
approaching bowing line from east-central MS could pose a
severe-weather threat with eastward extent.  Ongoing shower and
thunderstorms across northern AL should limit the northward extent
of greater destabilization to central parts of that state.  These
factors suggest a new WW will need to be considered within the hour
to the east of WW 114.

At 0850Z, the QLCS extended from east-central MS (Kemper to Clarke
counties), and then southwest through southern MS to southeast LA
(approaching Lake Pontchartrain and the New Orleans metro area). 
Moderately strong instability and effective bulk shear/vectors of
50+ kt crossing the southern extent of the QLCS into southern MS and
southeast LA suggest embedded tornadoes will remain a threat, in
addition to damaging winds.  Latest VWP at Slidell, LA indicated
large low-level hodograph curvature, favoring a continued tornado
threat (0-1 km SRH close to 300 m2/s2).

..Peters/Thompson.. 04/03/2017

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

ATTN...WFO...BMX...MOB...JAN...LIX...

LAT...LON   29249119 30569062 31339013 31608938 32118885 32808862
            33048734 33188701 33098635 32698596 31868599 31668611
            31348730 30888760 30368735 30008738 29848795 29648833
            28968861 28578898 28518948 28559039 28749125 29249119

Mesoscale Discussions in Alabama, 2017Mesoscale Discussions in Mississippi, 2017Mesoscale Discussions in Louisiana, 2017Every mesoscale discussion in 2017

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.