Thu, 5 May 2011 22:42:31 -0500
Some readings from the Thursday 12z run of the Hi-Res ECMWF | | I went into the office (WFO Dodge City) to interrogate the ECMWF since
that's the only way I can get a look at more fields since they aren't
available on the internet. After looking at this more, I am swaying
more toward the southern scenario... as in go south Saturday... and
stay south for the duration of this good pattern. The upper low is
slower to move out in the ECMWF and latest GFS solutions. The best
forcing and dynamics will be too far west, I think, Sunday and Monday,
and the exit region of the northern jet ahead of the low will be
cofined wayyyy to the north over eastern Wyoming and Montana. This is
not good and will effectively spread the cap northward quite a
ways....into the cooler surface airmass that will not budge. There is
also a sharp gradient in upper level wind speeds with crappy upper
tropospheric flow over Nebraska and points north...with the greatest
flow over eastern Wyoming and Montana. If this were mid to late June,
this would be great for eastern Wyoming/Montana and western Dakotas
chasing, but it is early/mid May and it is still fairly cool up there
and quality moisture just won't make it that far northwest.
This leaves the southern solution. There are a lot of pros for the
southern scenario. 1) Quasi-stationary dryline position day after
day Saturday through Tuesday with southern branch jet spreading
northeast across Texas. Hot surface temperatures and dryline
convergence should help alleviate concerns of initiation, but there
will likely be at least one of these days that will probably cap bust.
Wednesday May 11 looks to be the big day with the main trough/jet
coming out nosing into southern Kansas/Oklahoma. The GFS is faster
suggesting Tuesday would be the most active day (most numerous
storms).
ECMWF dailies:
Saturday -- weak 999mb surface low with convergence max 00z near
Childress with ~ 2500 J/kg CAPE nearby. No QPF being generated.
Sunday -- stronger low level momentum with dryline convergence from
roughly Enid south to Abilene TX. 2500-3000 J/kg CAPE all along
dryline, but CAPE drops off toward central TX. QPF being generated
Red River south to Abilene TX
Monday -- very similar to Sunday...dryline convergence roughly Enid to
Abilene, but may see some moisture mixout farther south toward central
TX... 35-40 knots at 500mb...250mb flow stronger in TX ~ 60-65 knots
weaker toward northern OK/KS around 35 knots. No QPF being generated
anywhere along dryline.
Tuesday -- Same song, third verse. QPF being generated at nose of
southern branch way down near Uvalde, TX (one of our favorites!) and
also in western OK... 2500-3000 J/kg CAPE from Del Rio, TX all the way
into IA.
Wednesday -- The big day in the ECMWF. All sorts of QPF being
generated along dryline/Pacific cold front from southern South Dakota
all the way into southern Texas.
Thursday -- Play scraps in Texas somewhere?
Bottom line is for Sunday and Monday, I am not really in favor of the
weak flow between the two jets up north...and best low level
convergence will probably be confined well to the west away from the
best moisture. I'm swaying toward going ALL IN on the dryline
beginning Saturday Childress to Wichita Falls and just staying down in
north Texas (give or take a 100 miles or so) for the duration of this
pattern.
-Mike U
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