Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 231732
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1132 AM CST FRI JAN 23 2015

.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015

NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS. A
SERIES OF WEATHER SYSTEMS WILL MOVE THROUGH THE AREA OVER THE NEXT
SEVERAL DAYS.

&&

.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015

A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE
IT DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH
THE GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH
THE LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND
LATEST HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT
PRECIP/REFLECTIVITY TRENDS LATE THIS MORNING INTO THE EARLY
AFTERNOON OVER NORTHERN IOWA.

DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD
HANDLE ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE
23.07Z RUN. THE CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE
CAVEAT...THE QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK
ENOUGH TO HOLD TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH
SUNSHINE EARLY ON IN THE DAY TO PUT TEMPS WELL INTO THE 40S...AND
THUS TWEAKED UP MAX TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015

TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.

A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.

&&

.AVIATION...23/18Z
ISSUED AT 1132 AM CST FRI JAN 23 2015

OVERNIGHT A STRATUS DECK COULD DEVELOP AND MOVING INTO THE
AREA...BUT CONFIDENCE IS RELATIVELY LOW. SATELLITE IMAGERY DEPICTS
SUCH CLOUDS APPROACHING FROM NORTHERN MN BUT ON A TRAJECTORY TO
JUST CLIP NORTHEAST IA. ALL MODEL GUIDANCE INDICATES DEVELOPMENT
OF LOW CLOUDS OVER EASTERN SD AND WESTERN MN TODAY...APPARENTLY
THOSE THAT WOULD FOLLOW THE STEERING FLOW DOWN INTO CENTRAL IOWA
TONIGHT...BUT CURRENTLY SATELLITE AND OBSERVATIONS SHOW CLEAR
SKIES OVER THOSE AREAS. SUSPECT THAT THE MODELS POOR HANDLE ON
CURRENT SNOW COVER MAY BE LEADING TO OVERZEALOUS PREDICTIONS OF
NEAR SURFACE MOISTURE AND CLOUD DEVELOPMENT. HOWEVER...WITH MVFR
CIGS ALREADY IN THE TAFS HAVE MAINTAINED THEM AND WILL WATCH
OBSERVATIONAL TRENDS TO OUR NORTHWEST THIS AFTERNOON AND TONIGHT.

&&

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

&&

$$

SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...LEE


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