NASA - National Aeronautics and Space Administration

Forecast Based on

• on satellite
• current surface observations
• 00 UTC ETA
• 00 UTC NGM
• 09 UTC MAPS/RUC
• MRF
• 12z ECWMF

Synopsis

An upper level ridge is analyzed over the northern Plains. A surface trough extends
from northeastern NE to western TX. The winds are southerly at 15-20 kts. The satellite
picture shows plenty of upper level moisture over the Rockies with cirrus streaming
over KS and OK.

Prog Discussion

Two strong shortwaves (one over southern Alberta, the other at 45N, 130W) will flatten
the upper level ridge and dig a trough over the midwest in the next 48 hours. A strong
pressure gradient will form the Rockies through the Plains as deep surface low tracks
across the northern Plains. The winds will be strong and gusty today and tomorrow. A
cold frontal passage on the morning of April 25 will result in the southerly winds
shifting to strong northwestly winds. With the abundant moisture from the former Pacific
northwest system, cirrus clouds will persist today and tomorrow. Mid level clouds will
form after the frontal passage. The skies will clear late in the afternoon on the 25th.

48 hour Forecast:

12z 24 Apr - 00Z 25 Apr: Highs in the 70s. Winds out of the southwest at 20 kts.
Persistent cirrus of varying thickness.

00Z 25 Apr - 12Z 25 Apr: Lows in the upper 40s. The front will pass around midnight.
The winds will shift from southwestly to northwesterly.

12z 25 Apr - 12Z 26 Apr: Cooler temperatures: upper 60s. Winds from the northwest at
20+ kts gusting to 30 kt. Early morning, mid and upper level cloudiness. Clearing
in the late afternoon.

Extended Range Discussion:

12z 26 Apr - 12Z 27 Apr: The upper level trough will progress to the eastcoast. Kansas
will be in an area of subsidence. High pressure will build in after the front causing
light winds and clear skies. Temperatures in the ~70.

Walker and Mace