Severe Thunderstorm Warning 52, NWS Des Moines, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
355 AM CDT FRI JUN 4 1999

WILL FOCUS ONLY ON THE FIRST 2 PERIODS OF THE FORECAST AND LEAVE THE
REST ALONE.

TWO AREAS OF CONCERN THIS MORNING ARE...FIRST THE LINE OF STORMS NOW
OVER NORTHEAST SECTIONS OF THE FORECAST AREA. THESE STORM WILL MOVE
EAST OF THE AREA BY AROUND 10Z. SO FAR NO SEVERE WEATHER TO REPORT.
SECOND AREA SOON TO BE IN WESTERN SECTIONS OF THE FORECAST AREA AND
WILL CONTINUE TO PROPAGATE EAST THIS MORNING AND HAS THE POTENTIAL OF
PRODUCING SOME SEVERE WEATHER UNTIL 12Z. 88D WIND PROFILE SHOWING 45
KTS AT 3000 FEET...SO GOOD INFLOW WILL CONTINUE INTO THE STORMS OVER
WESTERN IOWA THROUGH THE EARLY MORNING HOURS. ANTICIPATING THIS LINE
TO WEAKEN THIS MORNING. HOWEVER LEFT OVER OUT FLOW BOUNDARY MAY BE
CAUSE FOR FOCUS OF AFTERNOON CONVECTION.

MODELS DOING POORLY WITH QPF IN DETERMINING THE AREAS OF CONVECTION
THIS MORNING. WILL GO WITH THE ETA MODEL FOR THIS FORECAST PACKAGE.
MAIN CONCERN WILL BE FOR TONIGHT AS LOW LEVEL JET STRENGTHENS AND LOW
LEVEL WARM ADVECTION INCREASES ESPECIALLY OVER WESTERN IOWA. WARM
FRONTAL BOUNDARY OVER CENTRAL SECTION OF THE STATE HELPING TO FOCUS
LIFT AND WITH CAPES AROUND 4000 TO 5000 J/KG AND SHEAR VALUES IN THE
30S THE POTENTIAL FOR SEVERE WEATHER WILL BE SIGNIFICANT AS
WELL...WILL HIGHLIGHT THIS IN THE ZONES.

.DSM...NONE