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000
FXUS63 KDMX 191725
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1225 PM CDT SUN MAY 19 2013

.UPDATE
ISSUED AT 1122 AM CDT SUN MAY 19 2013

BRIEF RESPITE FROM CONVECTION OVER OUR AREA CONTINUES...WITH
INSTABILITY CURRENTLY CONFINED TO SOUTHEAST IOWA. TEMPS AND DEW
POINTS ON THE RISE AND SOUTHERLY WINDS PICKING UP ACROSS THE
REGION UP TO 15 TO 30 MPH. BRIEF WIND SPEED JUMP ALONG WARM FRONT
IN NORTHERN IOWA WITH GUSTS TO NEAR 45 MPH PAST FEW HOURS...HAS
NOW MOVED NORTH INTO SOUTHERN MINNESOTA. PROGGED UPPER LEVEL WINDS
EXPECTED TO INCREASE RAPIDLY THIS AFTERNOON AND WITH INSOLATION
INCREASING ACROSS THE AREA...EXPECTING LINE INITIATION OVER KS/NE
TO MOST LIKELY BE THE MAIN AREA OF CONVECTION THIS AFTERNOON AND
EVENING. WATCHING OLD MCV OVER WESTERN IOWA NOW...WHICH TRYING TO
SPIN UP CONVECTION NOW...MAY SEE ISOLATED STRONG STORM IF
INSTABILITY CATCHES UP WITH FEATURE PRIOR TO EXITING NORTHERN
IOWA.


.SYNOPSIS...
ISSUED AT 407 AM CDT SUN MAY 19 2013

AMPLE WEATHER DURING THE FORECAST PERIOD WITH ONGOING CONVECTION
PASSING THROUGH THE FORECAST AREA. THIS ARC OF THUNDERSTORMS IS
EXPECTED TO PROGRESS NORTHEAST OUT OF THE AREA TOWARD 12Z. THERE
MAY BE SOME LINGERING CONVECTION...HOWEVER IT APPEARS THERE WILL
BE SOME DOWN TIME DURING THE DAY WITH WEAK SUBSIDENCE ON THE
BACKSIDE OF THIS CONVECTION THIS MORNING. THIS SHOULD ALLOW DAYTIME
HEATING TO PROGRESS WITH INSTABILITY INCREASING THROUGHOUT THE
DAY. WILL ALSO SEE SHEAR BEGIN TO INCREASE AS MID LEVEL SPEED MAX
APPROACHES LATE IN THE DAY. POTENTIAL FOR SEVERE WEATHER LOOKS
GOOD BY LATE AFTERNOON INTO THE EVENING WITH BEST PARAMETERS
ACROSS THE SOUTH. ALL MODES OF SEVERE WEATHER WILL BE POSSIBLE
INCLUDING LARGE HAIL...DAMAGING WINDS WITH A FEW TORNADOES ALSO
POSSIBLE...ESPECIALLY IN THE SOUTH AND WEST.

THE CONVECTION WILL PULL NORTHEAST ACROSS CENTRAL IOWA TONIGHT AS
SHORTWAVE MOVES QUICKLY THROUGH THE STATE. WILL LIKELY SEE
CONVECTION DIMINISH OVER THE FORECAST AREA LATE TONIGHT AS DRIER
AIR ALOFT MOVES ACROSS THE STATE. EXCEPTION WOULD BE IN THE FAR
NORTH WHERE FORCING LINGERS AND CONVECTION MAY PERSIST FOR MUCH OF
THE NIGHT. WILL CONTINUE TO MONITOR THIS AREA FOR POTENTIAL HEAVY
RAINFALL AND THE POSSIBILITY OF FLASH FLOODING GIVEN THE PREVIOUS
HEAVY RAINS OF EARLIER IN THE WEEK.

UPPER LOW WILL SIT AND SPIN FOR THE EARLY PART OF THE WEEK
BRINGING CHANCES OF CONVECTION ON MONDAY INTO TUESDAY WITH
ADDITIONAL THREAT OF SEVERE WEATHER...MAINLY EAST DURING THIS
TIME AS MOISTURE AND SHEAR REMAIN IN PLACE. UPPER SYSTEM WILL
EVENTUALLY PULL AWAY LATER IN THE WEEK WITH DRIER WEATHER INTO
THURSDAY AND FRIDAY. HOWEVER...THE BREAK APPEARS SHORT LIVED AS
WARM ADVECTION AND MOISTURE TRANSPORT INCREASE LATE FRIDAY INTO
SATURDAY. THIS WILL BRING ADDITIONAL CHANCES FOR THUNDERSTORMS
LATE IN THE PERIOD.
&&


.AVIATION...19/18Z
ISSUED AT 1225 PM CDT SUN MAY 19 2013

OLD MCV CONTINUES TO PRODUCE SHOWERS AND ISO THUNDER WEST EARLY THIS
PERIOD AS IT DRIFTS NORTH.  MAIN CONCERNS WILL BE APPROACHING
SHORTWAVE LATE AFTERNOON AND EVENING WHICH SHOULD SET INSTABILITY
OFF. WINDS COMPLICATED THIS AFTERNOON WITH GUSTY SOUTH WINDS ALONG
AND BEHIND WARM FRONT WHILE CIRCULATION OVER WESTERN SECTIONS
BRINGING VRBL WIND DIRECTION/SPEED NEXT SEVERAL HOURS. LIKELY TO SEE
+TSRA OVER THE REGION AFT 00Z SPREADING FROM WEST TO EAST DURING THE
EVENING...TIMED PERIOD ABOUT 4 HOURS. MESO MODELS SUGGEST LINE
MAINLY PRIOR TO 06Z...WILL MONITOR FOR TIMING AND MAKE APPROPRIATE
UPDATES AS NECESSARY.


&&

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

$$

UPDATE...REV
SYNOPSIS...COGIL
AVIATION...REV