GOES-10 Science Test
Weather Synopsis - 07 April/12UTC to 08 April/12UTC 1998

Synoptic Situation:

The upper air pattern was characterized by a weak blocking ridge over southern Canada, with a very strong (130 knot) jet undercutting the block across the southern United States. A broad trough persisted over the western U.S., with a slow-moving closed low over the central Plains and another shortwave crossing the southern Rockies into the southern Plains. A weak ridge aloft was situated along the East Coast.

At the surface, an occluding low over eastern Kansas and Nebraska moved slowly northeastward into Iowa. A warm front was lifting northward across Missouri, Illinois, Indiana and Ohio, while a cold front/dryline moved across Oklahoma and Texas toward the lower Mississippi valley region.

Another cold front moved southward from the northern Plains into the central Plains, providing a reinforcing shot of cold air behind the Kansas/Nebraska surface low. In the West, a frontal system approached northern California.

Weather Conditions:

Strong convection erupted across the much of the central U.S., and also over the southern Plains. Much of the strongest convection was focused by enhanced low-level convergence and warm air advection lifting along the warm front across Iowa, Illinois, and Indiana. Multiple tornadoes were reported across Iowa and Illinois, with one tornado reported in Texas. Numerous reports of large hail were received across Illinois (up to 4.5 inch diameter hail), Iowa, Missouri, and Texas (each reporting hail as large as 1.75 inch diameter). Smaller hail or damaging winds were reported over Missouri and Oklahoma.

Precipitation was widespread from the northern Plains into the Ohio Valley and New England. Boundary layer convergence north of the slow-moving central Plains low helped to enhance rainfall rates over Nebraska and Iowa -- 2.5 inches of rain was recorded at Offutt Air Force Base near Omaha, with 1.75 inches a t Omaha. Convection produced rainfall accumulations up to an inch over parts of Missouri, Illinois, Indiana and Ohio.

Rainfall totals from convection across Texas, Arkansas and Louisiana into the Tennessee Valley region were generally in the 0.5 to 1.0 inch range.

Widespread snow fell across much of the Rockies, with amounts up to 6-11 inches in parts of Colorado and Utah. Light snow was also reported in northern Minnesota.