SPRING 2010 EXTENDED FORECAST

SPRING 2010 EXTENDED FORECAST:
ISSUED 16 MARCH 2010:

APRIL, MAY, AND JUNE - THE TIME PERIOD WILL START OUT DRYER AND WARMER THAN NORMAL, BUT IN THE END WILL AVERAGE OUT BY JUNE.......SEVERE WEATHER POTENTIAL EXISTS ALL SPRING, BUT TIMES TO REALLY WATCH ARE: APRIL WEEK 3, MAY WEEK 3, JUNE WEEKS 1 AND 4.

ABOUT 85 PERCENT OF THE 45 TO 65 THUNDERSTORMS IOWA EXPERIENCES ANNUALLY OCCUR BETWEEN APRIL AND SEPTEMBER WITH THE PEAK MONTH BEING JUNE. AT TIMES, THESE THUNDERSTORMS BECOME SEVERE PRODUCING HAIL, HIGH WINDS, TORRENTIAL RAINS AND AN OCCASIONAL TORNADO. TORNADO OCCURRENCES AVERAGE ABOUT 46 PER YEAR SPREAD OVER 16 DAYS WITH MAY AND JUNE BEING THE PEAK MONTHS OF TORNADO OCCURRENCE. HAIL OCCURS MOST FREQUENTLY IN MAY; HOWEVER, NEARLY HALF OF THE CROP-HAIL DAMAGE COMES IN JULY WHEN CROPS ARE MORE SUSCEPTIBLE TO YIELD-REDUCING DAMAGE. IN THE AVERAGE YEAR, HAIL DESTROYS ABOUT 1.4 PERCENT OF IOWA’S CORN CROP AND 4.5 PERCENT OF ITS SOYBEAN CROP. HAIL LOSSES ARE GREATEST IN NORTHWEST IOWA WHERE HAIL STORMS ARE TYPICALLY MORE SEVERE AND ALSO SOMEWHAT MORE FREQUENT THAN IN THE SOUTHEAST. IN ANY ONE LOCATION, HAIL LARGE ENOUGH TO CAUSE CROP/PROPERTY DAMAGE WILL OCCUR ON ABOUT TWO TO FOUR DAYS PER YEAR.


APRIL – AVERAGE TEMPERATURE: 60F (6 DEG ABOVE NORMAL)
PRECIP: 1-2 INCHES (1-2 INCHES BELOW NORMAL)

WEEK 1: RAIN AND WARM
WEEK 2: RAIN/THUNDER THEN SUNNY AND COOLER
WEEK 3: THUNDERSTORMS THEN SUNNY AND WARMER
WEEK 4: SUNNY AND VERY WARM – THEN THUNDERSTORMS

MAY – AVERAGE TEMP 68F (4 DEG ABOVE NORMAL)
PRECIP: 4 INCHES (1.5 INCHES ABOVE NORMAL)

WEEK 1: THUNDERSTORMS THEN SUNNY
WEEK 2: SUNNY THEN THUNDERSTORMS AND WARM
WEEK 3: THUNDERSTROMS THEN COOLER
WEEK 4: HOT AND HUMID/AFTERNOON (AIRMASS) THUNDERSTORMS

JUNE – AVERAGE TEMP 73 ( NEAR NORMAL)
PRECIP: 4 INCHES (NEAR NORMAL)

WEEK 1: HOT AND HUMID/AFTERNOON (AIRMASS) THUNDERSTORMS
WEEK 2: SUNNY AND COOLER
WEEK 3: THUNDERSTORMS THEN SUNNY, HOT AND HUMID
WEEK 4: HOT AND HUMID/AFTERNOON (AIRMASS) THUNDERSTORMS