332
FXUS63 KDMX 041121
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
620 AM CDT SAT JUL 4 2009
UPDATED FOR THE 12Z AVIATION DISCUSSION
SHORT TERM /TODAY/
UPPER LEVEL DISTURBANCE MOVING THROUGH THE REGION NOW...EXPECTED TO
DROP EAST SOUTHEAST OF THE STATE BY LATE TODAY...ALLOWING FOR PRECIP
TO DIMINISH ACROSS THE AREA THROUGHOUT THE DAY. FAIRLY DECENT AREAL
COVERAGE ACROSS THE CWA...WITH THIS TREND EXPECTED TO CONTINUE TO
WIDESPREAD LIFT HANGING INTO THE MID MORNING HOURS. MAINLY LIGHT
SHOWERS...BUT A LINE OF THUNDERSTORMS MOVING ACROSS PORTIONS OF
CENTRAL AND SOUTH CENTRAL IOWA SHOULD CONTINUE TO BRING MODERATE TO
HEAVY RAIN AT TIMES THROUGH THE NEXT FEW HOURS. RAINFALL AMOUNTS
HAVE MAINLY RANGES FROM AROUND A TENTH TO HALF AN INCH...BUT HAVE
SEEN MUCH HIGHER REPORTS FROM SITES BENEATH THE HEAVIER BAND OF RAIN
STRETCHING FROM NEAR ATLANTIC TO OSCEOLA SOUTHEASTWARD. THIS BAND
SHOULD CONTINUE TO PROGRESS SLOWLY EASTWARD WITH TIME THROUGH THE
MID MORNING HOURS...ALLOWING WIDESPREAD AMOUNTS OF AT LEAST A HALF
AN INCH TO AN INCH ACROSS THE SOUTHERN CWA. OTHERWISE PRECIP TO
TAPER OFF THIS AFTERNOON AS SYSTEM HEADS TOWARD THE OHIO VALLEY.
WITH CLOUDS/PRECIP ACROSS MUCH OF THE AREA TODAY...EXPECT LITTLE
RECOVERY IN TEMPS. THEREFORE WENT A LITTLE COOLER THAN PREVIOUS
GRIDS...WITH HIGHS MAINLY IN THE LOW TO MID 70S.
LONG TERM /TONIGHT THROUGH FRIDAY/
HIGH PRESSURE BUILDS IN TONIGHT...AND WHEN THE SKY CLEARS OUT THERE
IS THE GOOD POSSIBILITY FOR FOG TO DEVELOP UNDER THE RIDGE. WILL NOT
MENTION IN THE FORECAST YET...BUT IT IS SOMETHING TO WATCH FOR LATER
SHIFTS. THE NEXT ISSUES APPEAR RELATIVELY MINOR...BUT UNDER AN
UNUSUALLY MOIST NORTHWESTERLY FLOW PATTEN AND A WEAK BACKDOOR FRONT
MOVING SOUTH AND SOUTHWEST INTO THE REGION LATE SUNDAY INTO
MONDAY...CANNOT JUSTIFY KEEPING THE FORECAST COMPLETELY DRY
EVERYWHERE. IT IS GOING TO BE DIFFICULT TIMING THE INDIVIDUAL
SHORTWAVES THAT COULD ENHANCE CONVECTIVE POTENTIAL...BUT IT SEEMS
THAT ONE WILL BE MOVING TOWARD NW IA LATE SUNDAY...THEN ANOTHER ONE
MOVING THROUGH MONDAY. A NARROW CORRIDOR OF MODEST INSTABILITY WITH
LITTLE INHIBITION DEVELOPS SUNDAY AFTN NW INTO CENTRAL SECTIONS.
HOWEVER...DEEP LAYER SHEAR ON THE WEAK END. SAME THING MONDAY AFTN
THOUGH A LITTLE FARTHER SOUTH AND WEST. THE GFS TRIES TO BRING AN
MCS THROUGH WRN/CENTRAL AREAS EARLY MONDAY...BUT THIS IS NOT
SUPPORTED BY PREVIOUS RUNS...SO WILL DISCOUNT THAT SCENARIO AT THIS
TIME. THE CONVECTIVE POTENTIAL SUNDAY AND MONDAY APPEAR MORE
DIURNALLY DRIVEN...WITH LITTLE CHANCES FOR CONVECTION AFTER
MIDNIGHT. WILL KEEP TUESDAY DRY FOR NOW...BUT CHANCES FOR
THUNDERSTORMS RETURN BY WEDNESDAY ACROSS THE NORTH...ON THE EDGE OF
THE CAP AND CLOSER TO FORCING. CHANCES SPREAD SOUTH LATE IN THE WEEK
AS A FRONT PUSHES SOUTH. OTHERWISE...TEMPERATURES WILL BE CLIMBING
BACK TO NEAR NORMAL.
AVIATION
04/12Z
TRICKY AVIATION FORECAST TODAY...WITH LINGERING SHOWER ACTIVITY
ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE PUSHING THROUGH THE STATE
TODAY. IFR/MVFR CIGS IN PLACE ACROSS THE CWA...WITH MVFR VSBYS DUE
TO MAINLY RAIN SHOWERS. THUNDER ACTIVITY HAS MAINLY DIED OFF OVER
THE PAST FEW HOURS...SO REMOVED CB MENTION AT KDSM AND KOTM. CIGS TO
REMAIN QUITE LOW THROUGH THE MORNING...WITH CIGS EXPECTED TO START
LIFTING BY THIS AFTERNOON INTO THE EVENING HOURS AS THE
PRECIPITATION TAPERS OFF. WINDS TO BACK THROUGH THE DAY...CURRENTLY
EASTERLY THEN BECOMING NORTHEASTERLY...AND FINALLY NORTHERLY BY
TONIGHT.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...ALBRECHT
LONG TERM...MOYER
AVIATION...ALBRECHT
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