21 MARCH EXTENDED FORECAST

21 MARCH EXTENDED FORECAST

A RIDGE OF HIGH PRESSURE HAS BUILT INTO NORTHWEST IOWA AS A LOW PRESSURE SYSTEM OVER ARKANSAS IS DRAWING WARM MOIST AIR INTO SOUTHEASTERN IOWA. MUCH OF THE STATE IS UNDER MOSTLY CLEAR SKIES. LAST NITES LOWS WERE MAINLY IN THE 20S AND 30S...ALTHOUGH MASON CITY DROPPED AS LOW AS 18 DEGREES. WINDS ARE GENERALLY FROM THE NORTH TO NORTHEAST AT 5 TO 10 MPH THIS MORNING.

FAIR WEATHER SHOULD HOLD FOR THE NEXT COUPLE DAYS THROUGHOUT THE REGION EXCEPT FOR PARTS OF MISSOURI AND ILLINOIS...WHICH WILL REMAIN UNDER THE INFLUENCE OF A STRONG LOW PRESSURE SYSTEM THROUGH LATE THIS EVENING. A FRONTAL SYSTEM IS EXPECTED TO MOVE INTO THE AREA TUESDAY AFTERNOON - EXPECT ISOLATED SHOWERS TUES EVENING THRU EARLY WED MORNING. HIGHS TODAY SHOULD BE IN THE 40S AND 50S...THEN WARM TO THE 50S AND 60S TOMORROW AND TUESDAY.

TODAY AND MON 21ST/22ND - PARTLY CLOUDY - HIGH TEMP 48-55

TUES AND WED 23RD/24TH - PARTLY TO MOSTLY CLOUDY WITH ISOLATED SHOWERS - HIGH TEMPS 55-60

THURS 25TH - RAIN SHOWERS - TEMPS LOW 50'S

FRI AND SAT 26TH/27TH - PARTLY TO MOSTLY CLOUDY - SATURDAY RAIN SHOWERS/THUNDER - TEMPS LOW 50'S

SUN 28TH - RAIN SHOWERS - TEMPS MID 50'S

MON AND TUES 29TH/30TH - MOSTLY CLOUDY AND BECM WINDY

WED 31ST AND THURS, APRIL 1ST - RAIN SHOWERS

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SPRING 2010 EXTENDED FORECAST

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: SUNNY AND WARMING
WEEK 3: THUNDERSTORMS THEN SUNNY AND COOLER
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