Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 260435
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1130 PM CDT FRI JUL 25 2014


.UPDATE...
ISSUED AT 1130 PM FRI JUL 25 2014

COMPLEX SCENARIO TONIGHT AS A WEAK FRONTAL BOUNDARY PUSHES INTO IA.
COOLER AIR ALOFT COULD WEAKEN THE CAP AS A SHORTWAVE PUSHES INTO
WRN/NW IA BETWEEN 09Z-12Z.  SMALL CLUSTERS OF STORM ALREADY ONGOING
IN CEN/ERN NEB AND SDKTA MAY MERGE AND DRIFT INTO NRN IA WELL INTO
THE OVERNIGHT.  THE NAM SUGGESTS THIS BUT IS PRETTY MEAGER ON QPF.
THE HOPWRF AND HRRR ALL SUGGEST SOME SORT OF MCS PUSHING INTO NW/NRN
IA THOUGH THAT LOOKS A LITTLE OVERDONE.  STILL...WITH THE 4 INCH
RAINFALLS IN LOCATIONS FROM LAST NIGHT AND THE SOUPY DEWPOINTS STILL
IN PLACE...HEAVY RAINFALL CANNOT BE RULED OUT.  FOR THE UPDATE I
WILL LIKELY EXPAND TSRA INTO NRN IA TOWARDS 12Z.  ANOTHER AREA OF
CONCERN IS FAR SRN/SE IA WHERE A WARM FRONT IS RESIDING AND PRETTY
STRONG WARM ADVECTION WILL BE FEEDING INTO A LLJ OF 30KTS.
ADDITIONAL STORMS MAY DEVELOP THERE AS WELL THOUGH ODDS GO WITH THE
INCOMING SHORTWAVE ACROSS THE NORTH AS THE BETTER LOCATION FOR
STORMS.  THERE WILL ALSO LIKELY BE SOME FOG TO DEAL WITH ACROSS THE
EASTERN THIRD TO HALF OF IOWA OVERNIGHT.

&&

.SYNOPSIS...
ISSUED AT 320 PM CDT FRI JUL 25 2014

LOW PRESSURE OVER SERN NEBRASKA WILL DRIFT EAST AS FRONTAL
BOUNDARY EXTENDING EAST FORM THE LOW BEGINS TO SINK SOUTH TONIGHT.
SECONDARY LOW WILL MOVE UP THE FRONT FROM THE SOUTHWEST ON
SATURDAY. HIGH PRESSURE WILL BUILD INTO THE REGION AND DOMINATE
THE WEATHER INTO NEXT WEEK.

&&

.SHORT TERM /TONIGHT/...
ISSUED AT 320 PM CDT FRI JUL 25 2014

WEAK LOW PRESSURE SYSTEM IN SOUTHERN NE WITH WEAK BOUNDARY INTO
SOUTHERN IOWA DID NOT ADVANCE AS FAR NORTH TODAY AS
ANTICIPATED...WITH CLOUDS FROM OVERNIGHT CONVECTION ALSO LINGERING
ACROSS THE AREA. THIS HELPED TO KEEP TEMPERATURES MUCH COOLER THAN
ANTICIPATED ACROSS CENTRAL AND SOUTHERN CWA. THEREFORE...WILL DROP
HEAT ADVISORY FOR REMAINING PORTION...LOCATIONS IN THE OLD ADVISORY
AREA MAY SEE HEAT INDEX VALUES NEAR 100 THROUGH THE REMAINDER OF THE
AFTERNOON...BELOW CRITERIA. IN ADDITION...HAVE DROPPED OVERNIGHT LOW
TEMPERATURES A FEW DEGREES AS WELL.

LOW WILL PUSH EASTWARD OVERNIGHT...THOUGH WILL REMAIN CAPPED ACROSS
THE CWA AND HAVE KEPT DRY FORECAST. SECONDARY LOW BEGINS TO
INFLUENCE AREA NEAR 12Z...THOUGH MODELS KEEP SYSTEM FURTHER
WEST...AND HAVE CUT POPS FOR END OF PERIOD.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 320 PM CDT FRI JUL 25 2014

FRONTAL BOUNDARY WILL REMAIN SOUTH OF IA THROUGH SATURDAY. LOW
PRESSURE WILL MOVE NEWD ALONG THE BOUNDARY ON SATURDAY WITH LOW
CHANCES FOR THUNDERSTORMS ACROSS THE SOUTH. GIVEN THE LITTLE NWD
PROGRESS OF THE WARM FRONT...DO NOT SEE A STRONG CHANCE OF
VIGOROUS THUNDERSTORM DEVELOPMENT AS FAR NORTH IA IA WILL KEEP IN
CHANCES ACROSS THE SOUTH...LEANING TOWARD THE FURTHER SOUTH
SOLUTIONS OF THE OF NAM.

HIGH PRESSURE WILL EXERT ITS STRENGTH INTO THE CENTRAL U.S. SAT
NIGHT INTO NEXT WEEK. THIS WILL KEEP TEMPS AT LEAST 5 TO 10
DEGREES BELOW NORMAL FOR A GOOD PART OF THE WEEK. THERE WILL BE
LITTLE CHANCE FOR ANY SIGNIFICANT RAINFALL.

&&

.AVIATION...26/06Z
ISSUED AT 1130 PM CDT FRI JUL 25 2014

CIGS ARE MESSY ACROSS TAF LOCATIONS WITH MVFR CIGS ACROSS THE NE AND
LOWER VFR CIGS ACROSS THE N AND HIGHER CLOUDS ACROSS THE SOUTH.  A
SOUPY AIRMASS COMBINED WITH LIGHT WINDS WILL LIKELY PRODUCE SOME
LIGHT DRIZZLE AND FOG. AN UPPER LEVEL FEATURE WILL MOVE IN BETWEEN
09Z-12Z OR SO AND COULD PRODUCE THUNDERSTORMS ACROSS NORTHERN TAF
LOCATIONS BUT AT THIS POINT COVERAGE LOOKS LIKE IT MIGHT BE ISOLD.
ADDITIONAL THUNDER POSSIBLE ACROSS SOUTHERN TAF LOCATIONS...MAINLY
KOTM AS A STALLED FRONTAL BOUNDARY PROVIDES FOCUS FOR TSRA AFT 20Z
OR SO.

&&

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

$$ UPDATE...FAB
SYNOPSIS...MS JUL 14
SHORT TERM...AWB
LONG TERM...MS JUL 14
AVIATION...FAB



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