Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 021728
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1228 PM CDT SUN AUG 2 2015

.SHORT TERM /TODAY/...
ISSUED AT 242 AM CDT SUN AUG 2 2015

EARLY MORNING CONVECTION OVER SOUTHERN MN CONTINUES TO MOVE EAST
WHILE IRSAT SHOWING CLOUDS COOLING OVER NORTHERN IA IN RESPONSE TO
WEAK IMPULSE AND WARM AIR ADVECTION CROSSING THE AREA. A FEW SHOWERS
HAVE ATTEMPTED TO DEVELOP...BUT EARLIER SUBJECTIVE H850 ANALYSIS
SHOWING DRY AIR ALOFT OVER MOST OF IOWA HINTS AT ONLY MODEST
DEVELOPMENT THROUGH REMAINDER OF OVERNIGHT. WILL MONITOR AND UPDATE
IF NECESSARY. SAME STORY ACROSS EASTERN NEBRASKA...STORMS FIRING IN
MORE FAVORABLE MOISTURE PLUME AT 0715Z...BUT AS THEY PROGRESS TOWARD
WESTERN CWA BOUNDARY BY 12Z...SUSPECT THEY TOO WILL GENERALLY WEAKEN
WITH TIME. THERE HAS BEEN AN ISOLATED CELL NEAR CASS COUNTY OVER THE
PAST HOUR SO A FEW STORMS MAY YET DEVELOP OVER THE SOUTH PRIOR TO
12Z. MEANWHILE FOR THE REMAINDER OF THE DAY...THE MAIN SFC LOW OVER
CENTRAL MN WILL TRACK EAST TODAY DRAGGING A BOUNDARY ACROSS THE AREA
BY LATE AFTERNOON. AHEAD OF IT...NARROW RIBBON OF WARM H850 AIR WILL
MIX DURING THE AFTERNOON HOURS BRINGING HIGHS CLOSER TO 90 OVER THE
SOUTH HALF WITH A FEW URBAN AREAS LIKELY REACHING LOWER 90S BY LATE
AFTERNOON. MUCAPE RISES TO OVER 3000 J/KG ALONG THE BOUNDARY IN THE
AFTERNOON HOURS WHICH SHOULD SUPPORT THE MARGINAL THREAT FOR A SVR
STORM AS SCATTERED STORMS DEVELOP. H700 TEMPS BUILDING TO 10-11C BY
00Z WHICH MAY INHIBIT UNTIL 21-00Z. FOR NOW WILL EXPECT A DRY
MORNING/EARLY AFTERNOON WITH BEST POTENTIAL FOR THUNDERSTORMS LATE
AFTERNOON WHICH CORRESPONDS TO TIME OF INCREASING 0-6KM BULK SHEAR
TO 30-35KTS AS WELL NEAR THE BOUNDARY. SOUTHWEST WINDS DURING THE
DAY WILL MIX TO 15 TO 25 MPH...SO BREEZY AT TIMES WITH DEW POINTS
REMAINING IN THE UPPER 60S TO LOWER 70S. THIS WILL PUSH THE HEAT
INDEX TO 95 TO 98F ACROSS THE SOUTH TODAY.

.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 242 AM CDT SUN AUG 2 2015

COLD FRONTAL BOUNDARY TO BE SITUATED ACROSS THE SOUTHERN PORTION OF
THE STATE BY EARLY EVENING...AND WILL CONTINUE TO PUSH SOUTH
OVERNIGHT. THEREFORE MAY SEE SOME STORMS ONGOING AT THE BEGINNING OF
THE PERIOD BEFORE ACTIVITY PUSHES SOUTH INTO MISSOURI BY LATE
EVENING. NAM TRIES TO HAVE FRONT STALL OUT ACROSS SRN IA...BUT SEEMS
TO BE THE OUTLIER WITH THE REMAINDER OF THE MODELS SHOVING IT
FURTHER SOUTH INTO MISSOURI AS AN AREA OF HIGH PRESSURE BUILDS INTO
THE STATE. THEREFORE HAVE MAINLY DRY CONDITIONS FOR LATE SUNDAY
NIGHT INTO MONDAY. MAY SEE THE FRONT LIFT BACK NORTHWARD A BIT AS A
WARM FRONT WITH A SLIGHT CHANCE FOR SOME STORMS ACROSS THE FAR
SOUTHWEST LATE MONDAY/MONDAY NIGHT. WAA THEN TO BEGIN AS THE FRONT
LIFTS NORTHWARD INTO THE STATE TUESDAY INTO WEDNESDAY. THIS OCCURS
IN RESPONSE TO A STRONGER SHORTWAVE TROUGH TOPPING THE WESTERN US
RIDGE AND PUSHING INTO THE NORTHERN PLAINS TUESDAY NIGHT INTO
WEDNESDAY. COULD SEE SOME LINGERING ACTIVITY INTO THURSDAY OR
FRIDAY AS THE FRONT HANGS UP ACROSS THE STATE BEFORE PUSHING BACK
SOUTH AS A STRONG COLD FRONT MOVES THROUGH THE STATE AND HIGH
PRESSURE BUILDS INTO THE GREAT LAKES/OHIO VALLEY REGION. THIS
SENDS H85 TEMPS DOWN TO AROUND +12C BY THE END OF NEXT WEEK INTO
NEXT WEEKEND. THEREFORE EXPECT GRADUAL COOLING THROUGH THE
WEEK...WITH TEMPS FALLING BACK TO NEAR OR SLIGHTLY BELOW THE
SEASONAL AVERAGES FOR THE BEGINNING OF THE WEEK. THEN TEMPS COOL
EVEN FURTHER TO BELOW THE SEASONAL AVERAGE WITH HIGHS MAINLY IN
THE 70S BY THE END OF THE WEEK INTO THE WEEKEND.

&&

.AVIATION...02/18Z
ISSUED AT 1228 PM CDT SUN AUG 2 2015

A COLD FRONT WILL APPROACH FROM MINNESOTA THIS AFTERNOON AND MOVE
ACROSS IOWA THIS EVENING. AHEAD OF THE FRONT EXPECT GUSTY WSW
WINDS AND NEARLY SKC...THEN THIS EVENING AS THE FRONT MOVES
THROUGH SOME LOW CLOUDS AROUND FL035-050 WILL DEVELOP ALONG WITH
ISOLD TO SCT TSRA...MAINLY ACROSS THE SOUTHERN HALF OF IOWA. HAVE
MAINTAINED SHORT DURATION VCTS GROUPS AT DSM/OTM THOUGH ANY STORMS
WILL BE VERY HIT AND MISS. ONCE THE BOUNDARY MOVES THROUGH SKIES
SHOULD CLEAR OUT AGAIN WITH WINDS BECOMING LIGHT AND VARIABLE
OVERNIGHT.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...REV
LONG TERM...BEERENDS
AVIATION...LEE


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