Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 301738
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1238 PM CDT TUE JUN 30 2015

.SHORT TERM /TODAY/...
ISSUED AT 351 AM CDT TUE JUN 30 2015

IOWA REMAINS IN ESTABLISHED NORTHWEST FLOW ALOFT WITH BAROCLINIC
ZONE SETTING UP ALONG THE MISSOURI RIVER VALLEY TODAY.  WARM
ADVECTION ACROSS THE DAKOTAS ALONG THIS TIGHTENING GRADIENT ALREADY
PRODUCING SOME SHOWERS AND THUNDERSTORMS OVERNIGHT. A WEAK WAVE
MOVING ALONG THE BAROCLINIC ZONE WILL HELP FOCUS LOW LEVEL
CONVERGENCE INTO WESTERN IOWA BY LATER THIS AFTERNOON ALONG WITH MID
LEVEL LIFT WHICH WILL SUPPORT SCATTERED THUNDERSTORMS ACTIVITY BY
LATER THIS AFTERNOON. HAVE INCLUDED LOW POPS IN THE FAR WEST BY MID
AFTERNOON AS CONVECTION EXPANDS INTO THE AREA ALTHOUGH THE BEST
THREAT FOR CONVECTION WILL BE INTO TONIGHT. OTHERWISE...CLOUDS WILL
BE ON THE INCREASE WITH THE APPROACHING SHORTWAVE IN ADDITION TO
SOME SMOKE FROM THE CANADIAN FIRES DRIFTING OVERHEAD.  THIS SHOULD
IMPACT TEMPERATURES WITH READINGS HOLDING BELOW NORMAL INTO THE
AFTERNOON.

.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 351 AM CDT TUE JUN 30 2015

THE UPPER MIDWEST WILL REMAIN IN A GENERAL NORTHWEST FLOW UNTIL WELL
PAST THE EXTENDED FORECAST PERIOD.  THIS WILL BRING SEASONAL
TEMPERATURES AND TOLERABLE HUMIDITIES TO THE REGION BUT WE WILL ALSO
BE SUSCEPTIBLE TO EVERY SHORTWAVE RIDING THROUGH THE FLOW.  THE
FIRST SHORTWAVE WILL IMPACT THE SOUTHWEST HALF OF THE STATE TONIGHT
INTO WEDNESDAY BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS.
WHILE WE ARE NOT LOOKING PARTICULARLY UNSTABLE...THERE IS SOME
PRETTY IMPRESSIVE SHEAR MOVING ACROSS SOUTHWEST IOWA AND AS SUCH
THERE WILL BE SOME THREAT OF STORMS BEING CAPABLE OF LARGE HAIL AND
DAMAGING WIND...ESPECIALLY IN THE EVENING.

THE MODELS ARE IN DECENT AGREEMENT WITH DROPPING ANOTHER SHORTWAVE
ACROSS THE SOUTHWEST HALF OF THE STATE THURSDAY INTO FRIDAY BUT
SHEAR IS ALMOST NON-EXISTENT AND INSTABILITY IS EVEN WEAKER THAN
TODAY SO WHILE WE MAY SEE SOME SHOWERS AND THUNDERSTORMS WITH THIS
SYSTEM THE THREAT OF SEVERE STORMS IS NOT IMPRESSIVE.

THE PARADE OF SHORTWAVES WILL CONTINUE THROUGH THE HOLIDAY WEEKEND
BUT OVERALL PRECIP CHANCES LOOK PRETTY LOW UNTIL LATE SUNDAY INTO
MONDAY WHEN A FRONTAL BOUNDARY WILL CROSS IOWA COINCIDENT WITH YET
ANOTHER SHORTWAVE. INSTABILITY WILL BE QUITE IMPRESSIVE AS THE FRONT
MOVES THROUGH DURING PEAK HEATING AND THERE WILL BE SUFFICIENT SHEAR
AS WELL SO SOME SEVERE STORMS CAN BE ANTICIPATED LATE SUNDAY AND
MONDAY.  TEMPERATURES WILL ACTUALLY BE SEASONABLY COOL THROUGH
FRIDAY WITH HIGHS FROM THE UPPER 70S TO MID 80S.  LOWER TO MID 80S
ARE EXPECTED FOR THE MOST PART OVER THE WEEKEND.

&&

.AVIATION...30/18Z
ISSUED AT 1231 PM CDT TUE JUN 30 2015

VFR CONDITIONS SHOULD PREVAIL FOR MUCH OF THE PERIOD...THOUGH
SMOKE WILL STICK AROUND TAF SITES THROUGH MUCH OF THE TAF
PERIOD...IF NOT ALL AS THE OVERALL FLOW WILL SEE LITTLE CHANGE.
STEERED AWAY FROM OVC SKIES SINCE MANY SITES ARE ONLY SEEING FU/HZ
FROM THE SMOKE. POSSIBILITY OF FOG AT SITES OVERNIGHT WITH LIGHTER
WINDS...BUT DRY AIR COMING IN TO THE NORTH TONIGHT MAY PREVENT IT
AT MCW/ALO. SHOWERS/STORMS AND POSSIBLE FOG AT FOD/DSM/OTM COULD
SEE VISBYS DROP FOR PERIODS INTO MVFR/IFR CONDITIONS.

&&

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

$$

SHORT TERM...COGIL
LONG TERM...FAB
AVIATION...CURTIS



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