SPC Mar 12, 2018 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook

Day 2 Outlook Image

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1125 PM CDT Sun Mar 11 2018

Valid 131200Z - 141200Z


Isolated thunderstorms are expected across portions of the Great
Basin and along the California coast.

...CA Coast/Great Basin...

Significant mid-level height falls are expected to spread inland
across the western US ahead of a strong short-wave trough that will
approach the CA coast late in the period. Large-scale forcing for
ascent will aid mid-level moistening across NV/OR/ID as lapse rates
steepen and convection should develop towards 14/00z as stronger
flow aloft translates into this region. Isolated thunderstorms are
expected across portions of the Great basin into the late evening

Farther west along the northern/central CA coast, profiles are
expected to cool significantly during the day as mid-level
temperatures drop in advance of approaching trough. Forecast
soundings suggest sufficient buoyancy will evolve by late afternoon
for lightning production within the deepest updrafts, primarily near
the coast.

..Darrow.. 03/12/2018

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SPC Mar 12, 2018 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook

Day 3 Outlook Image

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Mar 12 2018

Valid 141200Z - 151200Z


A few thunderstorms are possible Wednesday across portions of the
Great Basin into the central Rockies.

...Great Basin/Central Rockies...

Strong short-wave trough will translate into NV by 18z Wednesday
before ejecting into ID/WY by 15/06z. Large-scale forcing for ascent
should aid mid-level moistening as lapse rates steepen in advance of
this feature. Additionally, modest boundary-layer heating is
expected to contribute to destabilization and forecast soundings
favor at least some potential for deep convection ahead of the short
wave. While PW values will remain seasonally low across this region,
cold mid-level temperatures should enhance lightning production. For
these reasons have introduced 10% thunder probabilities to account
for convective potential primarily between 14/18z-15/02z.

..Darrow.. 03/12/2018

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SPC MD 115


MD 0115 Image

Mesoscale Discussion 0115
NWS Storm Prediction Center Norman OK
1008 PM CST Sat Mar 10 2018

Areas affected...Northeast TX...Far Southwest AR...Far Northwest LA

Concerning...Severe potential...Watch unlikely 

Valid 110408Z - 110615Z

Probability of Watch Issuance...20 percent

SUMMARY...Some isolated hail is possible tonight across portions of
northeast TX, far southwest AR, and far northwest AR.

DISCUSSION...Recent surface analysis places a low over central TX
with a warm front arcing east-northeastward into the Ark-La-Tex.
Cooling cloud tops have been noted within the IR imagery across
northeast TX region during the past two hours and recent regional
radar imagery has shown quick development over the area. 00Z FWD and
SHV soundings sampled a steep lapse rate environment (i.e. around
7.0 degree C per km) and MUCAPE over 1800 J/kg. Current mesoanalysis
suggests this environment still exists over the region and that
continued warm-air advection into the frontal zone is expected to
result in increased thunderstorm coverage. Strong vertical shear was
also sampled by the 00Z soundings (i.e. effective shear over 50 kt).

There is some uncertainty regarding short-term storm coverage, given
that the region is on the far southwest edge of the shortwave trough
progressing through the Ozark Plateau and forcing for ascent is
currently modest. However, storms should increase along the front
tonight and given the favorable kinematic and thermodynamic
environment, the potential for severe hail exists and trends will be
monitored for potential watch issuance. Low confidence in the
overall scenario currently precludes higher watch probabilities.

..Mosier/Guyer.. 03/11/2018

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


LAT...LON   33429610 33629513 33279335 32639303 32269385 32719621

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SPC MD 111


MD 0111 Image

Mesoscale Discussion 0111
NWS Storm Prediction Center Norman OK
1225 PM CST Wed Mar 07 2018

Areas affected...New Jersey...Southeast Pennsylvania...Southeast New
York...Southern New England

Concerning...Heavy snow 

Valid 071825Z - 080030Z

SUMMARY...Moderate to heavy snowfall is expected to continue across
parts of southeast Pennsylvania, New Jersey and New York City this
afternoon gradually spreading northeastward into southern New

DISCUSSION...The latest surface analysis shows a 995 mb low about
110 statute miles east of the southern Delaware coast. A pronounced
dry slot evident on water vapor imagery is located just off the New
Jersey coast. Water vapor imagery shows rapidly cooling cloud tops
over the last couple of hours in the southern part of the MCD area
and lightning strikes are also noted. This is due to the approach of
a band of large-scale ascent associated with a negatively-tilted
upper-level trough moving through the Mid-Atlantic. This combined
with strong isentropic ascent oriented parallel to the coast and
just inland is maintaining a band of moderate to heavy

Although surface temperatures from New Jersey north-northeastward
into southern New England are generally just above freezing,
temperatures have cooled a couple degrees over the last hour. This
dynamic cooling has resulted in a change-over from rain to snow in
the New York City vicinity over the last hour. The heaviest snowfall
is occurring within a band oriented from south-southwest to
north-northeast across New Jersey and southeastern New York. This
band will continue to spread north-northeastward into southern New
England this afternoon. Snowfall rates of 1 to 2 inches per hour
will be common. A few spots could receive snowfall rates of more
than 2 inches per hour especially related to convection. Locations
in far southeastern Massachusetts near Cape Cod will likely remain
rain through early evening.

..Broyles/Hart.. 03/07/2018

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


LAT...LON   40507320 39827419 39497519 39877578 40547564 42067372
            42587157 42557086 42237057 41807059 41337106 41007213

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