I'm pretty much committing myself to the northern target. I like the
look of the visible satellite with a lot of clearing in the
central/northern South Dakota area. 60s dewpoints will spread north
through the day. There is north-south baroclinic zone that will
develop, thanks to prolonged stratus farther west toward western South
Dakota. This will enhance local lifting due to frontogenesis... with
2500 to 3000 J/kg CAPE developing to the east over a large area.
Vertical shear is not spectacular this far north, but directional
shear will be adequate for nice storm organization and supercells.
A significant jet streak will be nosing up into Wyoming today allowing
fairly robust cyclogenesis around the Laramie Range. Southeast winds
will develop over eastern Wyoming in response, bringing in some lower
to perhaps mid 50s dewpoints as far west as harrison, NE and even
Lusk, WY. This is Target #1 (Lusk WY to Harrison, NE). Second target
is a north-south convergence zone whihch will develop north of a
secondary sfc low farther east. Much more abundant moisture will
exist in this area with dewpoints in the mid 60s as far northwest as
central SD by late in the afternoon. Upper winds will be a bit weaker
in this area, but direction shear will still support supercells.
Target #2 is west to northwest of Pierre. Below is the 11z RUC model
and the 06z NAM model valid around 00z time later on today: I will
either head west-northwest to Harrison, NE or north to Murdo, SD (then
northwest from there) leaving around 9am.
I'll update the chasemode status with which target I select.
...that both southeastern and southwestern NE were very poor plays today. H
eading to Kearney tonight to position ourselves for a drive to the north an
d west tomorrow.
Well... this sucks. Moisture mixed out, much like expected, actually,
but even more so than the models suggested (well, except for the HRRR,
as it really mixed moisture out over western/central Nebraska). The
best convergence is just too far west where dewpoints are in the
20s... so deep convection can't get started... it's just flat looking
cumulus that glaciates about 15,000 feet. Anyway, maybe some
lightning photography after dark up north, perhaps, but this one is a
bust... tomorrow still looks decent with much better forcing for
ascent at the nose of the incoming upper level jet streak up into the
northern Nebraska Panhandle and southwestern South Dakota.
I'm sitting near the Nebraska-Kansas border watching really high-based
cumulus with some ever slight verticality to my south and also to the
west-northwest. I think I'll sit here along Hwy 83 near Cedar Bluffs
KS and watch both of these areas. It's really dry right where these
cu are developing in the greatest convergence... the hope is that by 6
or 7pm, east-southeasterly flow will help bring some higher dewpoints
back in this area, but the hot, highly-mixed airmass is reducing
near-surface based CAPE substantially right where these cumulus are
developing. It's a wait and see game like it usually is...
Morning boys and Candice! Last night's run of the EMC 4km WRF was
rather enticing showing a string of pearls from western Nebraska down
into Oklahoma. Unfortunately, I don't think this is realistic. The
15 to 18hr RUC and HRRR are really keying in on moisture mix-out
across much of Kansas with highest CAPE nosing into
western/southwestern Nebraska. Latest GFS and NAM 06z runs still do
show convective attempts across southwest Nebraska at the nose of the
upper 90s heat axis. My idea for a target is bounded by
Ogallala-North Platte-McCook based on this (especially the 06z GFS
solution). We've really gotta get away from the moisture mix-out,
which means get north. Attached is the 06z GFS valid 03z and the 06z
NAM valid 00z both showing a small convective QPF signal (although not
as robust as previous runs)
It will be a fairly late show I do believe, thus even if we need to
get toward I-80 (which I think it looks like we probably will), then
we can still leave as late as Noon or so, but I'm going to be prepared
to leave my house by 11am. I will meet you guys down at your hotel
probably around your check-out time. -Mike U
Rob, Jon, Mitch, and Candice all arrived safely in Dodge City this
evening. They are staying at the Super 8 in town, while I get to deal
with thousands of moths. Yay is me. Tomorrow is a chase day... moths
or no moths... and if the EMC/NCEP 4km WRF model from this evening is
any decent prognostication of how the real atmosphere will play out
tomorrow, then Kansas will light up like a Christmas tree with
numerous supercells all up and down the dryline. There's actually
going to be some halfway decent convergence on the dryline tomorrow in
Kansas...including not too far northeast of Dodge City. This is
something to watch out for... even though the EMC WRF is the only
numerical model showing such a robust and favorable supercell signal
down the dryline. A minor shortwave trough will actually move across
the central plains tomorrow afternoon allowing enhancement along the
dryline. This may just be the impetus to initiate supercells. Take a
look at this evenings 00z run of the EMC/NCEP 4km WRF. Left image is
simulated composite reflectivity valid 8:00pm CDT Sunday evening.
Right image is a two panel comparison of 3-hr convective QPF from the
EMC WRF and the Operational NAM model.
