NWMSGuy
Member
Nice writeup by Memphis WFO this package:
Area Forecast Discussion
National Weather Service Memphis TN
340 PM CDT Tue Apr 12 2022
.DISCUSSION...
...Significant severe weather outbreak likely Wednesday afternoon
into Wednesday evening...
Currently...Upper ridging across the area has resulted in a good
deal of sunshine and excellent mixing today. This has brought down
stronger low level winds resulting in south winds gusting close to
40 mph at times. Wind advisory is in effect through 7 pm for the
Delta region. Temperatures have reached into the lower 80s across
most of the area this afternoon. A shortwave pushing into the
Lower MS Valley is starting to kick off convection SW of the
forecast area. Some blow off cloud cover is pushing into N MS
attm.
Tonight...The negatively titled shortwave will move NE through the
Mid-South overnight. Showers and thunderstorms will blossom and
push into SW sections of the Mid-South this evening and move NE
overnight, exiting west TN by mid morning Wed. 0-6km bulk shear
values of 35-40 kts, 50 kt 850mb LLJ, MUCAPES of 500-1000 j/kg and
mid level lapse rates of 7 c/km will support some severe weather.
Most likely area will be across east AR and NW MS where the
greater instability should be. It is hard to pinpoint the best
time for severe weather overnight. When storms first move in
during the evening surface based instability may be maximized.
Later in the evening when the shortwave approaches the shear will
be more supportive and LLJ intensifies so can`t really rule out a
severe storm any hour of the night. Winds will remain gusty
overnight especially over the Delta.
Wednesday...Storms from overnight convection will exit West TN by
mid-morning. Will probably see some sunshine develop as mixing
occurs ahead of the approaching cold front and potent mid level
trough pushing into the southern plains. Good mixing and a strong
surface pressure gradient will result in gusty south winds up to
40 mph by late Wednesday morning especially across the Delta. A
wind advisory has been issued. Instability should increase nicely
as dewpoints in the mid and upper 60s advect north and surface
heating warms temps to around 80 over the Delta. By 18z model
soundings across the Delta look impressive with SBCAPES above 3000
j/kg and 0-3km helicity values greater than 300 m2/s2. Mid level
lapse are steep at 7.5 c/km. 12z CAMs indicates storms firing
along the cold front over southern MO starting by early afternoon
meanwhile discrete cells are likely to develop over the Delta and
track NE. These discrete cells could contain tornadoes, possibly
strong, and very large hail. A QLCS will then sweep across the
Mid-South with damaging winds and possible embedded tornadoes as
well. Perhaps the most concerning area for strong tornadoes is
south of I-40 and west of I-55 where HREF is highlighting some
impressive 24 hr UH tracks. Threat for severe weather will start
around 1 pm in east AR and eventually end by midnight along the
MS/AL line. Memphis metro will be under threat from 2 pm (west
metro) to 9 pm (east metro). The broad window is to cover the
discrete cells followed by the QLCS.
Areas along the KY/MO border picked up 1.5+ inches of rain
yesterday so considering the high PWs and the likelihood of a
couple rounds of heavy rain went ahead and issued a Flash flood
watch for northern sections of the Mid-South for tonight through
Wednesday evening.
Thursday and Friday...Quiet period with zonal flow aloft and weak
high pressure at the surface with seasonable temps.
Weekend into early next week...A warm front will try to lift north
and stall near the region bringing chances for showers and
thunderstorms to the Mid-South as upper level disturbances move
through in the zonal flow aloft. A more significant shortwave
moving through Sunday night may clean out the area for early next
week with dry and cool conditions Monday and Tuesday.
Area Forecast Discussion
National Weather Service Memphis TN
340 PM CDT Tue Apr 12 2022
.DISCUSSION...
...Significant severe weather outbreak likely Wednesday afternoon
into Wednesday evening...
Currently...Upper ridging across the area has resulted in a good
deal of sunshine and excellent mixing today. This has brought down
stronger low level winds resulting in south winds gusting close to
40 mph at times. Wind advisory is in effect through 7 pm for the
Delta region. Temperatures have reached into the lower 80s across
most of the area this afternoon. A shortwave pushing into the
Lower MS Valley is starting to kick off convection SW of the
forecast area. Some blow off cloud cover is pushing into N MS
attm.
Tonight...The negatively titled shortwave will move NE through the
Mid-South overnight. Showers and thunderstorms will blossom and
push into SW sections of the Mid-South this evening and move NE
overnight, exiting west TN by mid morning Wed. 0-6km bulk shear
values of 35-40 kts, 50 kt 850mb LLJ, MUCAPES of 500-1000 j/kg and
mid level lapse rates of 7 c/km will support some severe weather.
Most likely area will be across east AR and NW MS where the
greater instability should be. It is hard to pinpoint the best
time for severe weather overnight. When storms first move in
during the evening surface based instability may be maximized.
Later in the evening when the shortwave approaches the shear will
be more supportive and LLJ intensifies so can`t really rule out a
severe storm any hour of the night. Winds will remain gusty
overnight especially over the Delta.
Wednesday...Storms from overnight convection will exit West TN by
mid-morning. Will probably see some sunshine develop as mixing
occurs ahead of the approaching cold front and potent mid level
trough pushing into the southern plains. Good mixing and a strong
surface pressure gradient will result in gusty south winds up to
40 mph by late Wednesday morning especially across the Delta. A
wind advisory has been issued. Instability should increase nicely
as dewpoints in the mid and upper 60s advect north and surface
heating warms temps to around 80 over the Delta. By 18z model
soundings across the Delta look impressive with SBCAPES above 3000
j/kg and 0-3km helicity values greater than 300 m2/s2. Mid level
lapse are steep at 7.5 c/km. 12z CAMs indicates storms firing
along the cold front over southern MO starting by early afternoon
meanwhile discrete cells are likely to develop over the Delta and
track NE. These discrete cells could contain tornadoes, possibly
strong, and very large hail. A QLCS will then sweep across the
Mid-South with damaging winds and possible embedded tornadoes as
well. Perhaps the most concerning area for strong tornadoes is
south of I-40 and west of I-55 where HREF is highlighting some
impressive 24 hr UH tracks. Threat for severe weather will start
around 1 pm in east AR and eventually end by midnight along the
MS/AL line. Memphis metro will be under threat from 2 pm (west
metro) to 9 pm (east metro). The broad window is to cover the
discrete cells followed by the QLCS.
Areas along the KY/MO border picked up 1.5+ inches of rain
yesterday so considering the high PWs and the likelihood of a
couple rounds of heavy rain went ahead and issued a Flash flood
watch for northern sections of the Mid-South for tonight through
Wednesday evening.
Thursday and Friday...Quiet period with zonal flow aloft and weak
high pressure at the surface with seasonable temps.
Weekend into early next week...A warm front will try to lift north
and stall near the region bringing chances for showers and
thunderstorms to the Mid-South as upper level disturbances move
through in the zonal flow aloft. A more significant shortwave
moving through Sunday night may clean out the area for early next
week with dry and cool conditions Monday and Tuesday.
