697 
FXUS63 KFSD 040750
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA 
NATIONAL WEATHER SERVICE SIOUX FALLS SD
250 AM CDT WED JUL 4 2012

.DISCUSSION...
A HOT HUMID HOLIDAY HAZARD AS WE HAVE BEEN ADVERTISING. THUNDERSTORM 
CHANCE SEEMS MINIMAL ENOUGH TO KEEP OUT. AFTER TODAY MODELS DIFFER 
ON PROGRESS OF WEAK FRONT INTO THE REGION. ENOUGH OF A GRADUAL 
INCREASE IN UPPER FLOW TO GO WITH THE MOISTURE AND BOUNDARY TO 
GRADUALLY BRING THUNDERSTORM THREAT IN FROM THE NORTHWEST STARTING 
TONIGHT...BUT LESS THREAT AND LESS FAST THAN SOME OF THE GUIDANCE. 
MODELS STILL SEEM TO BE TENDING TO BRING THE FRONT DOWN OVER OUR 
AREA TOO FAST THOUGH THERE DOES APPEAR TO BE A LITTLE SLOWDOWN FROM 
THE DAY RUNS. MOST NOTABLY SOME SLOW DAYTIME COOLING FROM THE 
NORTH...PARTLY DUE TO CLOUD AND MOISTURE INCREASE...WILL BE BALANCED 
BY THAT SAME POOING MOISTURE AND HIGH DEW POINTS OVER MORE OF THE 
AREA THAN AT PRESENT. THIS TREND WILL PREVAIL THROUGH FRIDAY AT A 
SLOW PACE AND GUARANTEE HIGH LOW LEVEL MOISTURE AND DEWPOINTS OVER 
THE AREA INCLUDING THE WEST WHERE THEY ARE NOT QUITE THAT HIGH NOW. 
SO...THOUGH HEAT INDEX VALUES IN CURRENT GRIDS ARE A LITTLE BELOW 
ADVISORY CRITERIA BY FRIDAY...I WILL KEEP THE ADVISORY GOING THROUGH 
THAT TIME FOR THE AREA TO ALLOW FOR A POSSIBLE FURTHER SLOWDOWN IN 
THE COOLING TO GO WITH THE GUARANTEED HIGH SURFACE DEWPOINTS/ 
HUMIDITY.

BY FRIDAY NIGHT INTO THE WEEKEND THE SLOW MOVING FRONT SHOULD EDGE 
FURTHER SOUTH OVER AND THROUGH AREA. WITH THE SLOW MOVEMENT SHOWERS 
AND STORMS WILL TEND TO BE ALONG AND NORTH OF THE FRONT SO THIS WILL 
BE OUR MAIN CHANCE...WHILE SLOW SURFACE COOLING CONTINUES. WILL 
LEAVE A SLIGHT CHANCE OF STORMS IN OUR FAR SOUTH/SOUTHWEST AS LATE 
AS MONDAY TO ALLOW FOR THE SLOWER EC SOLUTION WHILE GFS SUGGESTS DRY 
ACROSS THE BOARD. OTHERWISE MONDAY THROUGH TUESDAY NIGHT LOOKS DRY 
WITH SEASONABLE TEMPERATURES.

&&

.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH 05/06Z. A VERY ISOLATED THREAT FOR 
THUNDERSTORMS ALONG AN INCOMING BOUNDARY FROM ABOUT 04/23Z THROUGH 
05/6Z IN CENTRAL SOUTH DAKOTA...BUT A SMALL ENOUGH OF A THREAT WITH 
WARM AIR ALOFT THAT NOTHING WILL BE MENTIONED IN THE TAF. /08

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR IAZ001>003-012>014-     
020>022-031-032.

MN...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR MNZ071-072-080-081-089-
     090-097-098.

NE...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR NEZ013-014.

SD...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR SDZ038>040-050-052>071.

&&

$$