000
FXUS63 KDMX 220825
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
325 AM CDT WED MAY 22 2013

.SHORT TERM.../TODAY /...
ISSUED AT 325 AM CDT WED MAY 22 2013

UPPER LOW WILL DRIFT SLOWLY SOUTHEAST THROUGH THE STATE TODAY WITH
COMMA HEAD/DEFORMATION AREA SLIDING OVERHEAD. RECENT RADAR TRENDS
IN SOUTH DAKOTA AND SOUTHERN MN HAVE SHOWN AN INCREASE IN RETURNS
AND ANTICIPATE THIS PRECIPITATION ENTERING THE NORTH DURING THE
MORNING. HAVE GONE LIKELY TO CATEGORICAL ACRS THE FAR NORTH FOR
EXPECTED LIGHT RAINFALL WITH QPF GENERALLY QUITE LIGHT. FARTHER
SOUTH...THE PCPN WILL BE MORE SCATTERED IN NATURE WITH POPS
TAPERING OFF TOWARD MISSOURI BORDER TO JUST ISOLATED WORDING.
OTHERWISE... CLOUDINESS WILL BE WIDESPREAD WITH SOUNDING SATURATED
IN THE LOWER LEVELS ALONG WITH COLD ADVECTION. THIS COMBINATION
WILL KEEP DAYTIME HIGHS FROM CLIMBING MUCH AND READINGS ARE
EXPECTED TO BE STUCK IN THE 50S ACRS THE NORTHWEST WITH LOWER 60S
SOUTHEAST.

.LONG TERM.../TONIGHT THROUGH TUESDAY/...
ISSUED AT 325 AM CDT WED MAY 22 2013

LIGHT SHOWERS WILL SLOWLY DIMINISH AND PUSH OFF TO THE EAST WITH
THE UPPER LOW PRESSURE SYSTEM TONIGHT. ANY ADDITIONAL RAINFALL
AMOUNTS WILL BE VERY LIGHT...BUT HAVE HELD ONTO LIKELY POPS
THROUGH ABOUT MIDNIGHT AS SPRINKLES AND LIGHT SHOWERS WILL BE
FAIRLY WIDESPREAD ACROSS OUR NORTHEAST AND EAST CLOSE TO THE LOW.
FROM THURSDAY INTO FRIDAY A DEEP LAYER RIDGE WILL BUILD ACROSS THE
CENTRAL U.S. WHILE AT THE SURFACE A HIGH PRESSURE AREA FROM CANADA
WILL SLIDE DOWN INTO WISCONSIN. THIS WILL RESULT IN COOL AND DRY
WEATHER ACROSS IOWA ON THURSDAY AND FRIDAY...AND IN FACT EARLY ON
FRIDAY MORNING A FEW STATIONS IN THE NORTHEAST COULD DROP INTO THE
UPPER 30S IF WINDS GO CALM AND DEWPOINTS ARE LOW ENOUGH. AT THIS
TIME HOWEVER LOWER 40S ARE MORE LIKELY AND THE FROST THREAT
APPEARS LOW.

FROM FRIDAY NIGHT THROUGH EARLY NEXT WEEK A MORE ACTIVE WEATHER
PATTERN WILL SET UP...AS THE 500 MB RIDGE AXIS REMAINS NEARBY AND
IS REPEATEDLY OVERTOPPED AND FLATTENED BY IMPULSES MOVING THROUGH
THE FLOW. AT THE SURFACE A BROAD LOW PRESSURE AREA WILL DEVELOP
AND PERSIST IN THE LEE OF THE ROCKIES...WITH A PSEUDO WARM FRONT
SETTING UP SOMEWHERE AROUND SOUTHERN IOWA/NORTHERN MISSOURI AND
REMAINING ROUGHLY STATIONARY FOR SEVERAL DAYS. THIS WILL RESULT IN
SEVERAL ROUNDS OF THUNDERSTORMS ASSOCIATED WITH THE MID LEVEL
IMPULSES...HOWEVER THE TIMING OF THESE FEATURES AND THE LOCATION
OF THE FRONTAL ZONE REMAIN UNCERTAIN AT THIS TIME. THUS HAVE
GRUDGINGLY MAINTAINED BLANKET CHANCE POPS FROM FRIDAY NIGHT
THROUGH THE END OF THE FORECAST PERIOD. DESPITE THIS DURATION OF
POPS THERE SHOULD BE AT LEAST A COUPLE OF RELATIVELY DRY PERIODS
DURING THAT SPAN...BUT AS OF THIS WRITING SUCH PERIODS CANNOT BE
PREDICTED. ALL IN ALL THE WEEKEND AND EARLY NEXT WEEK WILL BE
FAIRLY WET AND ACTIVE WITH SOME SEVERE WEATHER POSSIBLE AT TIMES.

&&

.AVIATION...22/06Z
ISSUED AT 1151 PM CDT TUE MAY 21 2013

MAIN CONCERN WILL BE THE SHOWERS AND CEILINGS LOWERING WITH THE
UPPER LEVEL LOW MOVING EAST IN THE NEXT 24 HOURS. CURRENT UPPER
LEVEL SYSTEM REMAINS TO THE WEST BUT IS SLOWLY PROGRESSING EAST
OVERNIGHT. THIS WILL RESULT IN AN AREA OF SHOWERS OVER NORTHEAST
NEBRASKA AND SOUTHEAST SOUTH DAKOTA TO MOVE SOUTHEAST INTO THE
FORECAST AREA. THE MAIN AREA OF MVFR/IFR CIGS IS WEST OF A COLD
FRONT WHICH WILL SWING SOUTHEAST THROUGH 00Z THURSDAY. THE TIMING
OF THE SHOWERS HAS BEEN SLOWED BY 1-2HRS FROM PREVIOUS PACKAGE BUT
OTHERWISE TRENDS REMAIN THE SAME. STILL A HINT AT ISOLATED
CONVECTION DURING THE AFTERNOON WEDNESDAY...BUT CONFIDENCE REMAINS
LOW REGARDING CATEGORICAL COVERAGE SO HAVE ADDED VCTS TO SOUTHERN
AND EASTERN TAF SITES WHERE MORE SIGNIFICANT CAPE IS EXPECTED.
WINDS WILL INCREASE AFT 18Z MOST AREAS AS STRONGER GRADIENT
CROSSES THE REGION.

&&

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

&&

$$

SHORT TERM...COGIL
LONG TERM...LEE
AVIATION...REV