Just Great...Winter In Nebraska Again

[weatherwunder]

See The Bold Down Lower


198
fxus63 koax 250903
afdoma


Area forecast discussion
National Weather Service Omaha/valley NE
300 am CST Tuesday Mar 25 2003


Forecast challenges will be temperatures in the near term and
chances for convection Thursday...and possibilities for significant
winter weather into Friday.

Synopsis-
light rain showers have exited the county warning area and somewhat cooler and drier
air is now in control of the Missouri Valley. Only marginal cold air advection
taking place at 850mb...with upstream temperatures across the
western Dakotas actually a few degrees warmer than Nebraska.
Further aloft...decent height rises showing up at 500mb and 300mb
across The Rockies in advance of a strong Pacific wave. This wave
will kick off a strong early Spring storm system from middle to late
week.


Forecast-
weak warm air advection will get going today as the upper flow becomes westerly
over the north Central Plains. Passing middle and high clouds will
provide some heating today...likely enough to rise into the lower
60s in most areas. Mixing will be limited until late afternoon as
the surface high pressure ridge sinks south.


This ridge will initially inhibit moisture return into the plains as
low pressure develops in the western High Plains Wednesday. With
dry/warm southwest flow...expect temperatures to rise nicely
Wednesday afternoon. Latest mav guidance lifts temperatures into the
middle 60s...with the ETA model topping out near 80. A compromise seems to
work best here with numbers ranging from the lower 70s south to the
middle/upper 60s north.


Certainly the biggest forecast challenges will continue to surround
the Thursday through Friday time frame. There continues to be
differences in the placement and strength of the surface low Thursday.
However...a compromise of the ETA model and GFS takes the low along the
Kansas/NE border and crosses the Missouri River between 21z and 00z
Thursday afternoon. General consensus agrees that the county warning area will be
in the warm sector through the early afternoon and with such a
dynamically strong system...thunderstorms will be possible along the
cold front. However...moisture is cut off from the system initially
and convection that does occur is expected to be scattered. Will
continue chance probability of precipitation to cover this. Early Thursday
evening...sharply colder air will whip into the area. A change over
from shower activity to snow will occur during the early evening
northwest and the late evening southeast. Snow amounts will depend
on the amount of moisture entrained into the system at that point.
Either way...wind will be quite strong into Friday evening...which
will make even a few inches of snow dangerous. We will highlight
this in the severe weather potential statement again today.


Cold weather will dominate the region through Sunday
morning...before Pacific air returns Sunday afternoon and Monday.


Oma...none.


Ervin