000
FXUS63 KDMX 180829
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
329 AM CDT TUE JUN 18 2013

.SHORT TERM.../TODAY/...
ISSUED AT 328 AM CDT TUE JUN 18 2013

COMBINATION OF INVERTED TROUGH EXTENDING FROM CENTRAL IL INTO SWRN
MN INTO THE RED RIVER VALLEY...COMBINED WITH RATHER STRONG S/WV
ROTATING SOUTHEAST INTO SRN MN AND SPEED MAX MOVING INTO NWRN IA HAS
RESULTED IN VIGOROUS CONVECTION IN SOUTHWEST MN...ALBEIT ONE MAIN
CELL.  THOUGH PARAMETERS ARE WEAK...BEING ISOLATED IT HAS BEEN ABLE
TO MAINTAIN ITSELF.  EXPECT TO SEE SCATTERED CONVECTION DEVELOP IN
THE VICINITY OF THE FRONT AS S/WV ROTATES THROUGH TODAY.  THE BEST
CHANCE IS IN THE MORNING BEFORE THE S/WV PASSES THE AREA.  FEEL THE
NAMDNG5/ECMEF AND TO A DECENT AMOUNT THE GFS HAS A PRETTY GOOD
HANDLE ON THE PRECIP AREA AND HAVE DISCOUNTED THE NAM12/HRRR AND SOME
OF THE OTHER HIRES MODELS WITH THE DEVELOPMENT OVER WRN IA.  TEMPS
TODAY WILL BE A LITTLE COOLER THAN YESTERDAY WITH INCREASE CLOUDS
AND AND SOME CAA AT H8. GENERALLY MID 70S TO AROUND 80...A FEW
DEGREES WARMER IN HEAT ISLAND AREAS.

.LONG TERM.../TONIGHT THROUGH MONDAY/...
ISSUED AT 328 AM CDT TUE JUN 18 2013

WEAK RIDGE WILL REMAIN IN PLACE ACROSS CENTRAL PLAINS FOR THE
BEGINNING OF THE PERIOD. SHORTWAVE TO PUSH EAST ACROSS RIDGE WILL
BRING PRECIPITATION CHANCES FOR WEDNESDAY. HOWEVER TIMING IS STILL
A BIT UNCERTAIN...WITH MODELS IN POOR AGREEMENT ON TIMING OF WAVE.
HAVE KEPT TIMING NEAR GOING. MODELS DO INDICATE A SLIGHTLY FURTHER
SOUTH SOLUTION...WITH BEST PRECIPITATION CHANCES ACROSS SOUTHERN
IOWA/NORTHERN MISSOURI...AND HAVE BEGUN TO TREND POPS THAT WAY FOR
LATE WEDNESDAY AND EARLY THURSDAY. DO HAVE SOME CONCERNS FOR
SEVERE WEATHER LATE WEDNESDAY AFTERNOON...WITH CAPE VALUES
1000-2000 J/KG INDICATED...AND LITTLE IN THE WAY OF CAP. WEAK CAP
MAY BE ENOUGH TO HOLD OFF CONVECTION WITH LITTLE FORCING. HAIL/WIND
WOULD BE THE MAIN THREATS FROM ANY SEVERE STORMS. TEMPERATURES
WILL WARM STEADILY THROUGH THE PERIOD UNDER THE RIDGE...WITH
PRIMARILY SOUTHERLY FLOW AT THE SURFACE.

UPPER LEVEL LOW PUSHING EAST ACROSS CANADA WILL DROP A FRONTAL
BOUNDARY ACROSS NORTHERN PLAINS FOR THURSDAY/FRIDAY. MODELS HAVE
SPED UP TIMING A BIT ON THIS SYSTEM...AND HAVE THERE FORE CUT BACK
ON POPS ACROSS THE SOUTH FOR LATE FRIDAY. LARGE UPPER LEVEL LOW
PRESSURE SYSTEM EXPECTED TO PUSH ONSHORE IN PAC NW FOR END OF WEEK
WILL INFLUENCE WEATHER ACROSS IOWA FOR MUCH OF THE REMAINDER OF
THE PERIOD. AS THIS IS STILL OFF THE SHORE AND POORLY SAMPLED...DO
NOT HAVE HIGH CONFIDENCE IN TIMING...THOUGH MODELS ARE IN DECENT
AGREEMENT. AS LOW DIGS ACROSS THE ROCKIES...RIDGE LIFTS ACROSS
IOWA...WITH SHORTWAVES LIFTING THROUGH RIDGE.
HOWEVER...TIMING/LOCATION AGAIN PROBLEMATIC. LATEST MODEL RUNS
KEEP TRACKS WEST AND NORTH OF IOWA...AND HAVE TRENDED TOWARDS THIS
SOLUTION FOR THE WEEKEND KEEPING POPS OUT OF THE SOUTH.

&&

.AVIATION...18/06Z
ISSUED AT 1202 AM CDT TUE JUN 18 2013

WEAK BOUNDARY OVER SOUTHERN IOWA WILL CONTINUE MOVING SOUTHEAST. A
FEW CLOUDS REMAIN OVER CENTRAL SECTIONS AT THIS TIME...WITH AN AREA
OF THUNDERSTORMS IN WESTERN NEBRASKA MOVING EAST SOUTHEAST. AN UPPER
LEVEL SYSTEM OVER CENTRAL MN WILL DROP SOUTHEAST OVERNIGHT AND
SHOULD INCREASE SHOWER CHANCES WITH MID LEVEL CLOUDS TOWARD MORNING
ACROSS NORTHERN AND NORTHEAST SECTIONS FROM 11-16Z. SOME QUESTION AS
TO IF ANY INSTABILITY WILL REMAIN TOWARD MORNING. MODELS CONTINUE TO
SUGGEST THAT COLD POOL ALOFT MAY BE ENOUGH TO MAINTAIN SOME ISO
CONVECTION OVER THE NORTHEAST. FOR NOW...CONFIDENCE REGARDING TIMING
AND COVERAGE REMAINS LOW...SO WILL INCLUDE VCSH WORDING AT THIS
TIME. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD AS HIGH SHIFTS EAST
AND RETURN EAST SOUTHEAST FLOW TAKES OVER FROM 18/23 TO 19/02Z FROM
WEST TO EAST.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE

&&

$$

SHORT TERM...MS
LONG TERM...AWB
AVIATION...REV