Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 090447
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1147 PM CDT TUE JUL 8 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 328 PM CDT TUE JUL 8 2014

QUIET WEATHER EXPECTED OVERNIGHT WITH QUICK DECOUPLING THIS
EVENING ALLOWING WINDS TO DIE OFF TOWARD SUNSET. CU FIELD WILL
ALSO DISSIPATE AS DAYTIME HEATING SUBSIDES WITH CLEAR SKIES AND
LIGHT WINDS OVERNIGHT. TEMPERATURES WILL BE BELOW NORMAL OVERNIGHT
WITH CANADIAN RIDGE SLIDING INTO THE MISSOURI RIVER VALLEY. HAVE
GENERALLY GONE AT OR BELOW GUIDANCE...ESPECIALLY IN FAVORED AREAS
OF NISHNA VALLEYS IN THE WEST AND THE NORTH.

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 328 PM CDT TUE JUL 8 2014

MAIN FORECAST CONCERN DEALT WITH THUNDERSTORM CHANCES THURSDAY
NIGHT INTO FRIDAY AND AGAIN ON SATURDAY. LEANED TOWARD A BLEND OF
NAM/GFS/ECMWF THROUGH FRIDAY...THEN TOWARDS GFS FROM THE WEEKEND
INTO NEXT WEEK.

WEDNESDAY THROUGH FRIDAY...CANADIAN HIGH PRESSURE WILL CONTINUE TO
PROVIDE SLIGHTLY BELOW NORMAL TEMPERATURES AND MOSTLY CLEAR
SKIES THROUGH THURSDAY. MODELS HINTING ON A WEAK 500MB SHORTWAVE
TO CUT ACROSS THE NORTHEAST PORTION OF THE STATE ON WEDNESDAY
AFTERNOON...BUT FORECAST SOUNDINGS SUGGEST ANYTHING THAT DEVELOPS
WOULD BE ELEVATED AND WOULD HAVE TO FIGHT A LARGE DRY LAYER TO
REACH THE SURFACE. PLUS WITH LIMITED DEEPER MOISTURE AND FORCING
AVAILABLE...CONFIDENT TO LEAVE FORECAST DRY ATTM ON WEDNESDAY.

CUTBACK ON POPS ON THURSDAY PRIOR TO 00Z FRIDAY AS MODELS
CONTINUE TO SLOW DOWN SYSTEM LATE IN THE WEEK. MOISTURE TRANSPORT
AND THETA-E ADVECTION INCREASE THURSDAY EVENING INTO FRIDAY AHEAD
NEXT SURFACE LOW TO DEVELOP OVER THE WESTERN PLAINS. A 500MB
TROUGH LOOKS TO MOVE ACROSS THE STATE OVERNIGHT THURSDAY NIGHT
THROUGH FRIDAY MORNING AND HAVE HIGHEST POPS GOING DURING THIS
TIME. WITH THE SLOWER MODEL SOLUTIONS...KEPT LIKELY POPS ACROSS
THE EAST ON FRIDAY.

SATURDAY THROUGH TUESDAY...BOUNDARY LOOKS TO STALL OUT ACROSS
CENTRAL TO SOUTHERN IOWA DURING THE WEEKEND AND WITH VARIOUS WEAK
UPPER LEVEL SHORTWAVES MOVING ACROSS THE REGION...TIMING OF POPS
BECOMES TRICKY WITH THIS SCENARIO. CONFIDENT ENOUGH TO TRIM BACK
POPS FRIDAY NIGHT IN THE WEST TO NORTH WITH SOME WEAK RIDGING.
HOWEVER...WITH THE INCREASING MOISTURE AND INSTABILITY DURING THE
WEEKEND...HAVE CHANCE POPS GOING THROUGHOUT THE DAY SATURDAY AND
SATURDAY NIGHT AND THEN SLIGHTLY POPS ON SUNDAY. HIGH PRESSURE BY
EARLY NEXT WEEK PROVIDES ANOTHER DRY PERIOD THROUGH TUESDAY.

&&

.AVIATION...09/06Z
ISSUED AT 1146 PM CDT TUE JUL 8 2014

LITTLE CHANGE FROM PREVIOUS FORECAST...WEAK COOL FRONT PASSING
THROUGH AREA TONIGHT WITH A FEW AREAS OF BKN050...OTHERWISE SKC.

LOOKING UPSTREAM...LARGE PLUME OF SMOKE FROM CANADIAN FOREST
FIRES FROM THE NORTHWEST TERRITORIES CURRENTLY SPILLING ACROSS THE
NORTHERN PLAINS...STRETCHING INTO SOUTHERN SOUTH DAKOTA TONIGHT.
VSBY DROPPING DUE TO SMOKE AND HAZE ACROSS PORTIONS OF NORTH
DAKOTA AND AREA HAS EXPANDED SOMEWHAT SINCE 00Z. H700 RIDGE
EXPECTED TO BUILD SLIGHTLY TONIGHT AND MAY CONTINUE TRAJECTORY TO
PUSH SMOKE ACROSS REGION BY 15-19Z WED OVER MOST OF AREA. HAVE
INTRODUCED 6SM HZ OVER WESTERN AND SOUTHERN TAF SITES FROM 17Z TO
20Z AS A PRECAUTION AND FARTHER EAST BY 00Z. OTHERWISE...LIMITED
MIXING AND GENERALLY VFR CIGS EXPECTED WITH ANY AREAS OF CLOUDS
BECOMING SCT TO FEW BY 00Z. /REV

&&

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

$$

SHORT TERM...COGIL
LONG TERM...PODRAZIK
AVIATION...REV


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