SPC Center Public Severe Weather Outlook (PWO)

Public Severe Weather Outlook

PWO Image

1141 AM CDT MON MAR 19 2018

...Severe thunderstorms expected over parts of the Tennessee Valley
this afternoon and tonight...

  Northern Alabama
  Far northwest Georgia
  Far southern Middle Tennessee
  Extreme northeast Mississippi

  Several tornadoes, a few intense
  Scattered large hail, some baseball size
  Isolated damaging winds

  Strong tornadoes, very large hail, and damaging winds are
  expected across parts of the Tennessee Valley and Southeast
  during the late afternoon and evening.

Preparedness actions...

Review your severe weather safety procedures for the possibility
of dangerous weather today. Stay tuned to NOAA Weather Radio, 
weather.gov, or other media for watches and warnings. A tornado
watch means that conditions are favorable for tornadoes to form
during the next several hours. If a tornado warning is issued for
your area, move to a place of safety, ideally in a basement or
interior room on the lowest floor of a sturdy building.


..Grams.. 03/19/2018

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from SPC Convective Outlooks http://bit.ly/1Mw5lDA

SPC MD 139


MD 0139 Image

Mesoscale Discussion 0139
NWS Storm Prediction Center Norman OK
0108 AM CDT Mon Mar 19 2018

Areas affected...South-Central/Southeast
OK...North-Central/Northeast TX

Concerning...Severe potential...Watch unlikely 

Valid 190608Z - 190815Z

Probability of Watch Issuance...20 percent

SUMMARY...Large hail is possible with the rapidly developing storms
across south-central/southeast OK and north-central/northeast TX.
Limited temporal duration and areal extent of the threat is expected
to preclude the need for a watch.

DISCUSSION...Recent regional radar imagery has shown increased
reflectivity across south-central OK and adjacent far north-central
TX over the past half hour. Cooling cloud-tops have also been noted
within GOES-16 IR imagery. This development appears to be on the
leading edge of a low-amplitude, fast-moving shortwave trough
rotating around the parent upper system over the TX Panhandle.
Adding to the forcing for ascent is the approaching Pacific cold
front (analyzed from west of OKC southward to about 50 mi
east-southeast of SPS to southwestward through the TX Hill Country)
and subtle pre-frontal troughing. 

Given the elevated instability (sampled well by the 00Z FWD
sounding) and strong vertical shear, these storms are expected to
rapidly strengthen and pose a hail risk for portions of
south-central/southeast OK and north-central/northeast TX. The
anticipated short duration (i.e. about 3 hours) and limited areal
extent is expected to preclude the need for a watch.

..Mosier/Edwards.. 03/19/2018

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


LAT...LON   34619700 35059674 35229612 35099541 34679515 33879529
            33239560 32889662 33299738 34619700 

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from SPC Mesoscale Discussions http://bit.ly/2DE86pI

SPC MD 122


MD 0122 Image

Mesoscale Discussion 0122
NWS Storm Prediction Center Norman OK
0404 AM CDT Fri Mar 16 2018

Areas affected...Southern SD...Northern NE...Far
Southeast/East-Central WY

Concerning...Winter mixed precipitation 

Valid 160904Z - 161300Z

SUMMARY...A transition to winter precipitation is anticipated soon
with this mixed winter precipitation expected to persist for the
next several hours.

DISCUSSION...Current regional radar imagery shows a band of
precipitation, with embedded heavier cores and occasional lightning,
arcing from southwest SD through southeast NE. This band is on the
eastern periphery of the low-level jet where isentropic ascent is
maximized. This ascent, as well as ongoing moisture advection, is
shown well on the 300K theta surface. Mature cyclone responsible for
the low-level jet and increased forcing for ascent will continue to
fill over the next few hours, leading to a gradual weakening of the
low-level jet and isentropic ascent. However, precipitation will
likely continue for at the next few hours with some expansion in
light/moderate precipitation possible as the system moves eastward.

Wet-bulb effects are expected to cool surface temperatures across
the region a few degrees, resulting in a transition to mixed winter
precipitation. Warm nose in place across north-central NE and
south-central/southeast SD is expected to result in dominant
precipitation type of freezing rain. Rain rates in this area could
top 0.05"/hr in the heavier cores. Farther west, less pronounced
warm nose will result in profiles remaining cold enough for
primarily snow. Generally moderate snowfall rates are anticipated
but occasional/brief instances of snowfall rates around 1"/hr are

..Mosier.. 03/16/2018

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


LAT...LON   42440080 42310143 42060249 41820385 42140434 42930433
            43710375 44000272 44160134 43909825 43009746 42619844

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from SPC Mesoscale Discussions http://bit.ly/2IscZWE

Red Flag Warning issued March 14 at 4:10PM CDT until March 14 at 7:00PM CDT by NWS

…RED FLAG WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING FOR STRONG GUSTY WINDS, LOW RELATIVE HUMIDITY LEVELS, AND DRY FUELS FOR FIRE WEATHER ZONES 008, 020, 021, 022, 023, 024, 026, 034, 035, 036, 037, 038, 039, 040, 054, 055, 056, 058, AND 059… * AFFECTED AREA…Fire weather zones 008, 020, 021, 022, 023, 024, 026, 034, 035, 036, 037, 038, 039, 040, 054, 055, 056,