En el día de hoy hay muchas dudas en la inicialización de la convección. Ahora les dejo la discusión y algunos mapas, pero se puede ver un impresionante jet de capas bajas dominando a toda la zona, aunque la humedad no será tan elevada (según el GFS) como para producir un estallido generalizado del tiempo. Ahora, me llama tremendamente la atención como el GFS se morfo el actual mesosistema que esta siendo hacia el Este de Dakota del Sur, porque es impresionante en las imágenes de satélite, y les juro que es NADA en los campos del GFS, así que por las dudas habría que vigilar eso, porque ese error puede conducir a que hay más humedad, y a que a la tarde vuele antes, pero bueno, ya lo veremos durante el día
Les dejo los mapas de hoy y la discusión, y la seguimos!!...
500 hPa, Sábado a la noche:
4 Palenes, Sábado a la noche:
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
0745 am CDT Sat may 22 2010
Valid 221300z - 231200z
..there is a slight risk of severe thunderstorms across the northern plains...
..There is a slight risk of severe thunderstorms over parts of the Carolinas...
...
Upper air pattern this period will be dominated by a belt of fast
southwesterly flow from the lower Colorado River valley to the Dakotas/Minnesota on the
eastern flank of a large scale trough established over the western U.S. This
stronger flow will coincide with a slow-moving deep-layer frontal
zone along which the most significant perturbation will track out of
the intermountain region and over the Dakotas later today.
Downstream from the western U.S. Tough...upper ridge will build across
the MS valley and Great Lakes as a weakening upper trough is shunted
eastward across the Appalachians/middle Atlantic.
..nrn plains...
Potent low level jet of 50-60kt was continuing to transport high
Theta-E air northward across the Great Plains this morning beneath
well-defined cap/elevated mixed layer emanating from the higher
terrain upstream /ref lbf radiosonde observation with observed 8.6c per km 700-500mb
lapse rate...0.84 inch precipitable water...and 14c temperature at 700mb/.
Ongoing mesoscale convective system across eastern South Dakota was being fueled by this plume of elevated
instability and sustained by mass and moisture influx on the nose of
60kt low level jet. Additional/recent development has occurred on
the edge of the cap across eastern Nebraska and is forecast to drift into Iowa
this morning perhaps posing a threat for isolated large hail /ref
sels mesoscale discussion number 660/.
Another round of robust convective development is expected later
today across parts of eastern Wyoming and the adjacent High Plains as a
low-amplitude short wave trough emerges across the High Plains and
acts on warm and very unstable air mass from Nebraska northward across the
Dakotas. By late afternoon expect MLCAPE values in this area to
exceed 3000 j per kg. While cap will likely hold across much of the
plains south of Nebraska...combination of surface heating and weak height
falls with approaching short wave should be sufficient to overcome
remaining inhibition and support thunderstorm initiation in strongly
sheared deep-layer flow.
Thunderstorms will occur coincident with weak frontal wave tracking
northeastward along the surface front...and a dry line nosing east-northeastward near the
South Dakota/Nebraska border. Modest low level hodograph curvature and magnitude of
instability suggest that a couple of tornadoes and very
large/damaging hail will be possible with discrete
storms/supercells. This activity may struggle to become more
widespread initially due to strong capping and tendency for storms
to take on more linear characteristics and be undercut along the
frontal zone where strongest mesoscale forcing can act to further
erode the cap.
Forcing along the edge of the cap through the evening and then
strengthening nocturnal low level jet should contribute to severe
mesoscale convective system evolving across South Dakota...and perhaps parts of ND...and then
spreading east-northeastward into Minnesota through early Sunday morning.
..NC Piedmont to SC midlands...
Modest northwest flow of 20-30kt and gradual diurnal destabilization...with
SBCAPE ranging from 1000 to 2000 j per kg by afternoon...may support
increasing severe storm potential these areas. Forcing for larger
scale ascent will be subtle but it appears region will come under
the influence of weak height falls from the trough passing north of
the area and Lee-trough will become coincident with axis of greatest
forecast destabilization.
Effective bulk shear on the order of 30kt will further aid storm
persistence and organization with a few hailstones possibly
exceeding one inch along with locally damaging wind gusts.
..West Texas...
Hot temperatures exceeding 90f...terrain influences...and dry line
mixing may prove sufficient to overcome warm eml and result in
isolated storm development late this afternoon as indicated in some
numerical guidance. Chances for numerous storms appear low but
abundant cape and adequate shear this region suggest a conditional
low probability of severe hail/wind is warranted.
.Carbin/Rogers.. 05/22/2010
