Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 050941
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
341 AM CST FRI FEB 5 2016

.SHORT TERM /TODAY/...
ISSUED AT 340 AM CST FRI FEB 5 2016

RIDGE AXIS SLIDING OVER THE STATE EARLY THIS MORNING WITH LIGHT
WINDS. TEMPERATURES OVER NEW SNOWPACK HAVE DROPPED INTO THE SINGLE
DIGITS WITH A FEW HOVERING NEAR ZERO. HIGH CLOUDS HAVE BEGAN
STREAMING OVERHEAD AHEAD OF NEXT APPROACHING SHORTWAVE WHICH WILL
BE THE ISSUE FOR THIS PERIOD. WARM ADVECTION WILL INCREASE THIS
MORNING WITH AS SOUTH WINDS STRENGTHEN. CLOUDS WILL CONTINUE TO
THICKEN THROUGH THE MORNING AS ISENTROPIC LIFT PERSISTS. DEEPER
SATURATION HOLD OFF UNTIL THIS AFTERNOON WHEN SOME LIGHT SNOW IS
EXPECTED TO DEVELOP IN THE WEST. THIS PRECIPITATION WILL REMAIN
LIGHT AS MOISTURE REMAINS QUITE LIMITED WITH THE SYSTEM. BY THE
END OF THE PERIOD...THE SCATTERED PCPN SHOULD BE UPON THE I35
CORRIDOR ALTHOUGH INTENSITY WILL REMAIN QUITE LIGHT.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 340 AM CST FRI FEB 5 2016

ONGOING LIGHT PCPN WILL BE ONGOING ACROSS CENTRAL PORTIONS OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD AND WILL SLIDE
EASTWARD THIS EVENING BEFORE DEPARTING WITH THE SHORTWAVE AND
ASSOCIATED LIFT. AGAIN...ONLY A DUSTING OR A FEW TENTHS OF AN INCH
OF SNOWFALL ARE EXPECTED BEFORE THE PCPN DEPARTS. GIVEN THE
PACIFIC ORIGIN OF THIS SYSTEM...THERE IS LITTLE COLD AIR IN THE
WAKE OF THE TROF. WARM ADVECTION WILL BE ONGOING BY THE START OF
SATURDAY AS THERMAL RIDGING PASSES THROUGH THE PLAINS. SATURDAY
WILL BE THE BEST DAY OF THE WEEKEND WITH LITTLE THREAT OF
PRECIPITATION AND WARMING TEMPERATURES. THE RELATIVELY WARMTH WILL
CONTINUE INTO SATURDAY NIGHT AS THE THERMAL RIDGE CROSSES THE
STATE PRIOR TO THE ARRIVAL OF THE NEXT SYSTEM.

MODELS REMAIN VERY CONSISTENT WITH AMPLIFICATION OF THE UPPER FLOW
OVER THE CONUS INTO EARLY NEXT WEEK AS RIDGING INTENSIFIES ALONG
THE WEST COAST. THE NEXT SYSTEM DROPPING SOUTHEAST INTO THE REGION
ON SUNDAY INTO MONDAY WILL HELP TO CARVE OUT THE DEEPENING EASTERN
TROF AND BRING SUBSTANTIAL CHANGES TO THE WEATHER ACROSS IOWA.
WHILE THE FIRST HALF OF SUNDAY WILL NOT BE OVERLY BAD...THERE WILL
BE ONGOING COLD ADVECTION THROUGH THE DAY...SO HIGHS WILL LIKELY
OCCUR BY MIDDAY IN MOST LOCATIONS. HOWEVER...THE STRONG SURGE OF
COLDER AIR WILL ARRIVE LATE SUNDAY INTO SUNDAY NIGHT AS UPPER LOW
DEEPENS AND DROPS SOUTHEAST THROUGH THE REGION. SOUNDINGS BEGIN TO
SATURATE WITH A BROAD AREA ENTERING THE DENDRITIC GROWTH ZONE.
SNOW SHOWER/LIGHT SNOW IS LIKELY TO SPREAD INTO NORTHERN IOWA BY
LATE SUNDAY AFTERNOON AND PROGRESS ACROSS THE ENTIRE FORECAST AREA
ON SUNDAY NIGHT. LIGHT ACCUMULATIONS ARE EXPECTED WITH AN INCH OR
TWO POSSIBLE...HEAVIEST AMOUNTS ACROSS THE NORTHEAST. MORE OMINOUS
IS THE STRENGTHENING WINDS AS PRESSURE GRADIENT TIGHTENS. STRONG
NORTHWEST WINDS ARE EXPECTED ON SUNDAY NIGHT INTO MONDAY WITH
SUSTAINED VALUES OF 20 TO 30 MPH AND GUSTS LIKELY EXCEEDING 40
MPH...ESPECIALLY IN FAVORED OPEN/FLAT AREAS OF THE NORTH AND WEST.
SOUNDINGS INDICATE A DECENT MIXED LAYER ABOUT 1KM IN DEPTH
DEVELOPING LATE SUNDAY NIGHT AND CONTINUING THROUGH MONDAY ACROSS
MUCH OF THE FORECAST AREAS...BUT MORE WELL DEFINED TO THE WEST.
WINDS AT THE TOP OF THE LAYER ARE AROUND 35-40KTS IN THE EAST AND
OVER 50KTS AT TIMES IN THE WEST. GIVEN THE STRONG WIND
POSSIBILITIES AND WIDESPREAD SNOWPACK (CHARACTER OF SNOWPACK WILL
BE IMPORTANT) IN THE NORTH AND WEST...WIDESPREAD BLOWING
SNOW...REDUCED VISIBILITIES AND DANGEROUS TRAVEL CONDITIONS SEEM A
STRONG LIKELIHOOD AT THIS POINT AND WILL MONITOR CLOSELY FOR
POSSIBLE BLIZZARD CONDITIONS SUNDAY NIGHT INTO MONDAY. MUCH COLDER
AIR WILL ALSO ENTER THE STATE WITH WIND CHILLS TAKING A NOSE DIVE
WHICH WILL JUST ADD TO THE POOR CONDITIONS. THE COOLER AIR WILL
REMAIN THROUGH MIDWEEK WITH SOME MODERATION TOWARDS THE END OF THE
WORK WEEK. THERE APPEARS TO BE LITTLE THREAT OF PRECIPITATION
AFTER MONDAY OF NEXT WEEK AS WELL.

&&

.AVIATION...05/06Z
ISSUED AT 1143 PM CST THU FEB 4 2016

LOW CLOUDS HAVE MAINLY EXITED THE CWA...WITH SOME HIGH CLOUDS NOW
MOVING IN. WINDS MAINLY LIGHTER AND VARIABLE TO SHIFT AROUND TO
THE SOUTH/SOUTHEAST FOR FRIDAY. CIGS TO LOWER THROUGH THE DAY
BECOMING MVFR TO POSSIBLY IFR BY FRIDAY AFTERNOON INTO THE EVENING
AS A CHANCE FOR SOME LIGHT SNOW MOVES THROUGH. HAVE HIGHLIGHTED
WITH A MENTION FOR NOW...FOR TIMING. COULD SEE SOME VSBYS
REDUCTIONS WITH IT...BUT WILL FINE TUNE IN LATER ISSUANCES.


&&

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

&&

$$

SHORT TERM...COGIL
LONG TERM...COGIL
AVIATION...BEERENDS


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