Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 142137
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
337 PM CST SUN FEB 14 2016

.SHORT TERM /TONIGHT/...
ISSUED AT 336 PM CST SUN FEB 14 2016

SNOW HAS ENDED ACROSS THE CWA...WITH WINDS DIMINISHING. SOME
VISIBILITY REDUCTIONS STILL BEING NOTED AROUND 2-5 MILES ACROSS
THE CWA WITH BLOWING SNOW...AND SOME DRIFTING SNOW ACROSS
ROADWAYS. THIS SHOULD CONTINUE TO DISSIPATE AS THE WINDS DIMINISH
FURTHER BY EARLY EVENING...BECOMING LIGHT AND VARIABLE. WAA TO
CONTINUE OVERNIGHT...WITH WEAK UPPER LEVEL ENERGY CLIPPING WEST
CENTRAL INTO SOUTHWEST IOWA TONIGHT. CURRENTLY SOME LIGHT SNOW
ASSOCIATED WITH THIS IMPULSE OVER THE WESTERN DAKOTAS. EXPECT SOME
CHANCES FOR LIGHT SNOW ACROSS THE FAR WEST/SOUTHWEST BY LATE
EVENING INTO THE OVERNIGHT HOURS AS SOUNDINGS SATURATE FOR A FEW
HOURS. DO NOT EXPECT MUCH MORE THAN A DUSTING AT BEST. LOW LEVEL
MOISTURE TO INCREASE THROUGH THE NIGHT AS WELL...WITH MOISTURE
ADVECTION IN SOUTHWEST FLOW...AND LIGHT WINDS...THEREFORE COULD
SEE SOME PATCHY FOG DEVELOP LATE TONIGHT INTO TUESDAY MORNING.
GUIDANCE SUGGESTING DECENT REDUCTION IN VISIBILITY...WITH THE HRRR
HINTING AT SOME PATCHY DENSE FOG AS WELL. UNCERTAINTY IS HIGH...SO
HAVE JUST MENTIONED PATCHY FOG ACROSS THE ENTIRE CWA AT THIS TIME.

.LONG TERM /MONDAY THROUGH SUNDAY/...
ISSUED AT 336 PM CST SUN FEB 14 2016

ONE MORE QUICK SHORTWAVE LATE MONDAY NIGHT INTO TUESDAY BEFORE A
MUCH ANTICIPATED WARMUP TOWARDS THE END OF THE WORK WEEK AND INTO
NEXT WEEKEND. CONTINUED LEANING TOWARD A BLEND OF THE
SREF/GFS/ECMWF AS NAM REMAINS THE OUTLIER BEING TOO FAR NORTH WITH
THE SURFACE LOW MONDAY NIGHT INTO TUESDAY AND THUS HAVING MORE
PRECIP TYPE ISSUES.

MONDAY INTO TUESDAY...SURFACE HIGH PRESSURE MOVES INTO THE STATE
DURING THE DAY MONDAY BUT QUICKLY SHIFTS EAST TO MAKE ROOM FOR A
VERY FAST MOVING ALBERTA CLIPPER INTO THE REGION LATE MONDAY NIGHT.
COMPACT SYSTEM WITH DEEP AND STRONG FORCING PUNCHES INTO NORTHWEST
IOWA B/T 03-06Z TUESDAY AND MOVES ESE ACROSS THE CWA B/T 06-15Z.
THE DEEP QG FORCING RAPIDLY EXITS THE CWA B/T 15-18Z AND SHOULD
END ALL PRECIP BY MIDDAY TUESDAY. POTENTIAL FOR GOOD
FRONTOGENETICALLY INDUCED SNOW BAND TO SET UP FROM NW TO SE
OVERNIGHT MONDAY NIGHT INTO TUESDAY...WITH STRONG OMEGA...ROUGHLY
15-20 UBAR/S WITHIN THE DENDRITIC LAYER...CAN EXPECT A QUICK BURST
OF SNOW IN THIS AREA. NAM WANTS TO BRING IN A WARM LAYER ALOFT
MONDAY NIGHT...BUT THINK THE SYSTEM WILL BE MOVING TOO QUICKLY FOR
THIS WARM LAYER TO MAKE AN EFFECT ON PRECIPITATION TYPE OVERNIGHT
INTO TUESDAY MORNING. PLUS...THE WARM LAYER COOLS BELOW FREEZING
OR NEAR FREEZING ONCE THE DEEP MOISTURE ADVECTION PUNCHES INTO THE
STATE OVERNIGHT. HENCE...LOW CONFIDENCE WITH MUCH MIXED PRECIP
BUT CANNOT COMPLETELY RULE IT OUT AT THE ONSET B/T 03-06Z TUESDAY.
HAVE A MENTION OF FZRA ACROSS THE WEST DURING THIS TIME BUT WITH
NO ICE ACCUMULATION. THE FORCING IS STRONG ENOUGH TO OVERCOME ANY
ABOVE FREEZING SURFACE TEMPS OVER MUCH OF THE AREA EXCEPT ACROSS
THE SOUTHWEST. HERE...LEFT A MENTION OF RA/SN AS WARM BOUNDARY
LAYER SHOULD BE DEEP ENOUGH TO MELT THE FALLING SNOW. ALSO
MENTIONED PATCHY BLSN ACROSS THE NORTH TUESDAY AFTERNOON WITH
DECENT CAA DEVELOPING BEHIND THE CLIPPER SYSTEM. PLUS THE WINDS
HAD NO TROUBLE BLOWING SNOW AROUND TODAY AND WINDS TUESDAY
AFTERNOON LOOK A BIT STRONGER.

WEDNESDAY...ANOTHER WEAK SHORTWAVE CUTS ACROSS THE STATE AND MAY
BRING A FEW SCATTERED SNOW SHOWERS. LIKELY JUST STRATUS AS THERE
IS A LACK OF DEEP MOISTURE AND SIGNIFICANT FORCING WITH THIS
SYSTEM WEDNESDAY.

THURSDAY INTO SUNDAY...BIG WARMUP BEGINS THURSDAY AND LASTS
THROUGH THE WEEKEND. 850MB WARM UP TO +14C TO +17C BY THURSDAY
AFTERNOON BUT SOUNDINGS SUGGEST AN INVERSION SETTING UP THROUGH
THE DAY TRAPPING IN SOME LOW STRATUS...HINDERING TEMPERATURES FROM
GETTING TOO OUT OF HAND. THAT BEGIN SAID...THE WAA IS STRONG
ENOUGH TO WARM UP WELL INTO THE 40S AND MELT OFF MUCH OF THE SNOW
PACK. MORE OF A DOWNSLOPE EFFECT BY FRIDAY AS A DECENT CLIPPER
SKIRTS NORTH OF THE STATE. MUCH DRIER AIR...THUS CLEAR SKIES AND
LESS SNOW PACK...SO FRIDAY LOOKS TO BE THE WARMEST DAY IN THE
EXTENDED. SATURDAY WILL BE WARM AGAIN WITH MUCH OF THE SOUTHERN
HALF OF THE STATE REACHING THE 50S. ONE THING TO NOTE WITH THE
GOOD WARM UP AND MELTING SNOW PACK MAY LEAD TO THE POTENTIAL FOR
ICE JAMS AND EVEN MINOR RIVER FLOODING NEXT WEEKEND ACROSS
NORTHERN PORTIONS OF CENTRAL IOWA.

&&

.AVIATION...14/18Z
ISSUED AT 1144 AM CST SUN FEB 14 2016

SNOW TO MOVE OUT OF THE AREA OVER THE NEXT FEW HOURS...BUT
COULD STILL SEE SOME VSBY REDUCTION FROM BLOWING SNOW THROUGH THE
AFTERNOON HOURS. LOW STRATUS TO REMAIN ACROSS THE CWA INTO
MONDAY...WITH ANOTHER WEAK WAVE POSSIBLY BRINGING SOME LIGHT SNOW
TO KDSM IN THE OVERNIGHT HOURS. WINDS TO DIMINISH AND SHIFT AROUND
TO THE SOUTHWEST INTO MONDAY. INCREASING MOISTURE MAY LEAD TO CIGS
LOWERING AND POSSIBILITY OF SOME FOG.


&&

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

&&

$$

SHORT TERM...BEERENDS
LONG TERM...PODRAZIK
AVIATION...BEERENDS


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