NASA - National Aeronautics and Space Administration

Forecast based on

• on satellite
• current surface observations
• 00 UTC ETA
• 00 UTC NGM

Synopsis

A strong zonal jet extending eastward from the Pacific coast into the
Mississippi valley continues to be the dominant feature influencing the weather
over the central plains. A series of fast moving and rather vigorous shortwave
impulses are moving through the flow with the eastern-most of these causing
cyclogenesis over Nebraska and Kansas this morning. Upstream, a shortwave
impulse is approaching the northern California coast. Satellite imagery
shows that the zonal flow is rather dry with primarily mid and low level
cloudiness in the vicinity of the strongest dynamical forcing. A vigorous
westerly wind is setting up over the central plains as the surface low deepens
in Nebraska and Kansas.

Prog Discussion

Cyclogenesis will continue over the Plains as the low in Nebraska and
Kansas moves eastward today. Central Kansas and Northern Oklahoma will
experience strong southwesterly winds in an extremely tight pressure gradient
in the lower levels. The shortwave entering western North America will
cause height falls throughout the southwestern United States and spawn
surface low pressure near the four corners region during the next 24 hours.
Numerical guidance suggests that the upper tropospere will remain dry
during the period. Areas of cirrus cloudiness are expected to generate
in response to the deepening system in the Southwest, although the extent
of this development is uncertain at this time. The mid and lower troposphere
will remian dry through the period.

48 hour Forecast:

12z 19 Apr - 00Z 20 Apr: The sky will remain clear and the westerly winds strong
throughout the day. Wind speeds will be sustained near 20-25 knots with
gusts to 30 knots. High temperatures in the 70's.

00Z 20 Apr - 12Z 20 Apr: Continued clear with diminishing winds. Temperatures
are expected fall into the 50's.

12z 20 Apr - 12Z 21 Apr: High clouds are expected in the region during this
period as the low in the southwest deepens. Winds will become southerly
during the day with speeds less than 20 knots. Temperatures in the low
80's.

Extended Range Discussion:

12z 21 Apr - 12Z 22 Apr: The low in the Southwest will likely generate
mid level cloudiness and a chance of precipitation over the region Sunday
and Monday as it moves into the southern Plains.

Mace and Walker