000
FXUS63 KDMX 161740
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1240 PM CDT THU MAY 16 2013

.SHORT TERM.../TODAY /...
ISSUED AT 411 AM CDT THU MAY 16 2013

CLUSTER OF WEAK THUNDERSTORMS CONTINUES ACROSS THE SOUTHEASTERN CWA
IN AREA OF MOISTURE CONVERGENCE AND MOISTURE ADVECTION ALOFT. THIS
ACTIVITY IS EXPECTED TO WANE OVER THE NEXT FEW HOURS...AS MOISTURE
TRANSPORT ALOFT BECOMES ORIENTED FURTHER TO THE WEST AHEAD OF AN
APPROACHING MID LEVEL SHORTWAVE TROUGH. MOISTURE ADVECTION TO
INCREASE AND BECOME ORIENTED INTO THE SOUTHWESTERN TO WEST CENTRAL
CWA TOWARD MID MORNING TO MID AFTERNOON. THEREFORE COULD STILL SEE
SOME ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE FAR
SOUTH THROUGHOUT THE MORNING...AND THEN WESTERN CWA THIS AFTERNOON.
BETTER CHANCES REMAIN WEST/NORTH OF THE CWA CLOSER TO THE UPPER
LEVEL SHORTWAVE TROUGH...SO STUCK WITH SLIGHT CHANCE/CHANCE POPS
ACROSS THE AREA. ANY ACTIVITY TO REMAIN ELEVATED FOR THE MOST
PART...HOWEVER NAM SOUNDINGS DO SUGGEST POTENTIAL FOR A FEW SURFACE
BASED STORMS THIS AFTERNOON. HOWEVER DEEP LAYER SHEAR REMAINS WEAK
SO ANY SEVERE POTENTIAL IS MINIMAL.

AIR MASS ALOFT IS SIMILAR TO YESTERDAY...BUT CLOUD COVER EXPECTED TO
BE HIGHER THUS KEPT MAX TEMPS NEAR PERSISTENCE FOR TODAY BUT WENT A
DEGREE OR TWO COOLER DUE TO CLOUD COVER/PRECIP CHANCES.

.LONG TERM.../TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 411 AM CDT THU MAY 16 2013

VIGOROUS SHORT WAVE LIFTING NORTHEAST THROUGH COLORADO THIS
MORNING AND WILL ARRIVE OVER THE NORTHWEST PORTIONS OF THE REGION
TONIGHT. THE PREFERRED TRACK OF THIS SYSTEM HAS BEEN TRENDING
FARTHER TO THE NORTHWEST. THE FARTHEST NORTHWEST TRACKS WOULD KEEP
MUCH OF THE FORECAST AREA MOSTLY DRY TONIGHT INTO FRIDAY. THE LOW
LEVEL JET WILL BECOME RE-ESTABLISHED WEST OF IOWA THEN LEANING
NORTHEAST INTO MINNESOTA AS THE UPPER WAVE ARRIVES. AT THIS
POINT...HAVE KEPT POPS IN ESPECIALLY ACROSS THE NORTH WITH
GENERAL STEERING FLOW AND CORFIDI VECTORS POINTING EAST/SOUTHEAST.
THE WARM SECTOR WILL THEN BECOME ESTABLISHED OVER IOWA FRIDAY NIGHT
INTO SATURDAY.

THE UPPER RIDGE WILL BEGIN TO SHIFT EAST IN RESPONSE THE THE
DEEPENING TROUGH TO THE WEST WITH A CLOSE LOW EVENTUALLY
DEVELOPING ACROSS THE NORTHERN HIGH PLAINS ON SUNDAY. THIS WILL
BRING SOUTHWEST FLOW TO IOWA WITH SEVERAL PIECES OF ENERGY
RIPPLING THROUGH. THUNDERSTORMS WILL BEGIN TO ENTER WESTERN IOWA
AFTER MIDNIGHT SATURDAY THEN MORE PRONOUNCED CHANCES FOR
THUNDERSTORMS FOR LATE SUNDAY THROUGH MONDAY. THE POTENTIAL FOR
SEVERE WEATHER SUNDAY AND MONDAY STILL LOOKS THE BEST IT HAS THIS
SPRING. THE ENVIRONMENT WILL BE FAVORABLE FOR SUPERCELLS DURING
THIS PERIOD WITH GOOD INSTABILITY AND INCREASING SHEAR. AT THIS
TIME IT APPEARS FAVORABLE FOR TORNADIC ACTIVITY WHICH COULD PUT AN
END TO THE CURRENT TORNADO FREE STREAK ONGOING ACROSS IOWA.
TEMPERATURES THROUGH THE WEEKEND WILL BE ABOVE NORMAL AND IN THE
80S FOR SEVERAL DAYS. THE BOUNDARY WILL MOVE THROUGH MONDAY THEN
MORE SEASONAL WEATHER TO FOLLOW.

&&

.AVIATION...16/18Z
 ISSUED AT 1237 PM CDT THU MAY 16 2013

CEILINGS WILL REMAIN VFR THROUGH BEGINNING OF PERIOD WITH WINDS
FROM THE SE...AND MAY BE GUSTY BEFORE 00Z. APPROACHING BOUNDARY
WILL BRING AN INCREASE IN CLOUDS AND MAY SEE CEILINGS DROP TO LOW
VFR. IN ADDITION...PRECIPITATION CHANCES AT SITES INCREASING FROM
WEST TO EAST FOR LATE IN THE PERIOD. HAVE NOT INCLUDED MENTION
RA/TSRA AT SITES WITH UNCERTAINTY IN TIMING AND LOCATION ATTM...BUT
HAVE CONTINUED TREND OF LOWER CLINGS. MAY SEE MVFR OR LOWER
CEILINGS IF PRECIP IMPACTS SITES OVERNIGHT...BEFORE CONDITIONS
IMPROVE EARLY FRIDAY.

&&

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

&&

$$

SHORT TERM...BEERENDS
LONG TERM...DONAVON
AVIATION...AWB