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000
FXUS63 KDMX 200948
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
348 AM CST SAT DEC 20 2014

.SHORT TERM /TODAY/...
ISSUED AT 343 AM CST SAT DEC 20 2014

A COMPACT SHORT WAVE IS CURRENTLY MOVING ACROSS SOUTHWEST IOWA. LOW
LEVEL MOISTURE ADVECTION INITIALLY RESULTED IN AREAS OF FREEZING
DRIZZLE DURING THE EVENING HOWEVER MID LEVEL MOISTURE IMMEDIATELY IN
ADVANCE OF THE SHORT WAVE HAS BROUGHT AREAS OF ICE INTRODUCING AND
HAS SWITCHED THE PRECIPITATION TO VERY LIGHT SNOW AT TIMES.
SUBSIDENCE AND DRYING BEHIND THE SHORT WAVE WILL REMOVE THE ICE
INTRODUCTION AND WILL RETURN ANY PRECIPITATION BACK TO DRIZZLE OR
FREEZING DRIZZLE...DEPENDING ON THE SFC TEMPERATURES. THE MOST
FAVORED AREAS BETWEEN 6 AM AND NOON WILL BE ALONG AND EAST OF
INTERSTATE 35. A FEW ICY PATCHES WILL LIKELY DEVELOP ON ROADWAYS
THROUGH MID MORNING BUT DO NOT EXPECT MINOR ICE ACCUMULATIONS TO BE
WIDESPREAD ENOUGH TO WARRANT HEADLINES BUT MAY REQUIRE AN SPS FOR
MORNING TRAVEL. TEMPERATURES TODAY WILL AGAIN BE BELOW GUIDANCE AND
RELIANT ON MOISTURE ADVECTION WITH A THICK CLOUD SHIELD IN PLACE.
NOT MUCH CHANGE IN SFC DEWPOINTS THROUGH THE DAY WILL RELEGATE HIGHS
TO NEAR TO SLIGHTLY HIGHER THAN FRIDAYS TEMPERATURES.

.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 343 AM CST SAT DEC 20 2014

ACTIVE WEATHER PATTERN SETTING UP FOR EXTENDED...WITH MAIN
CONCERNS COMING AT BEGINNING AND END OF PERIOD. FOR BEGINNING OF
PERIOD...UPPER LEVEL TROUGH WILL KEEP SOUTHERLY FLOW AND MOISTURE
INCREASING ACROSS THE CWA. THIS MAY ALLOW FOR LIGHT PRECIPITATION
IN THE OVERNIGHT HOURS...ESPECIALLY AS FORCING ARRIVES NEAR 06Z.
NAM HAS FORCING FURTHER SOUTH...AND MAY NOT BE FAR ENOUGH SOUTH
WITH POPS. HOWEVER...MAIN CONCERN FOR OVERNIGHT AND INTO SUNDAY
WILL BE WITH PRECIPITATION TYPE. SURFACE TEMPERATURES WILL DROP
BELOW FREEZING IN THE NORTH...AND WITH SHALLOW LOW LEVEL MOISTURE
MAY NOT SEE ICE INTRODUCTION...LEADING TO FZDZ POTENTIAL.
HOWEVER...SOUNDINGS ALSO INDICATE UPPER LEVEL MOISTURE ARRIVING
LATE IN THE OVERNIGHT WHICH MAY HELP TO KEEP PRECIPITATION SN.
MODELS TRYING TO INDICATE SLEET...THOUGH HAVE KEPT MENTION OUT
ATTM WITH MELTING OF ANY ICE INTRODUCED UNLIKELY. THEREFORE HAVE
KEPT FZDZ MENTION IN THE NORTH/NORTHEAST...WITH DZ
ELSEWHERE...CHANGING TO RN/SN MIX IN THE EARLY MORNING HOURS
BEFORE SWITCHING BACK TO RAIN IN THE AFTERNOON SUNDAY. GIVEN
UNCERTAINTY IN PRECIPITATION TYPE AM NOT CONFIDENT ENOUGH TO ISSUE
ADVISORY ATTM...THOUGH WILL NEED TO BE MONITORED.

SURFACE LOW WILL PUSH INTO IOWA FOR LATE IN THE WEEKEND...KEEPING
PROLONGED PRECIPITATION CHANCES INTO EARLY NEXT WEEK. WILL SEE
PRIMARILY RAIN WITH SYSTEM AS TEMPERATURES WILL BE ABOVE
FREEZING. MODELS INDICATING DRY SLOT ACROSS MUCH OF CENTRAL IOWA
FOR MONDAY...AND HAVE CUT BACK ON POPS SLIGHTLY IN THE SOUTH
MONDAY. PRECIPITATION WILL RETURN WITH COLD AIR AS LOW PULLS
EAST...WHICH WILL SEE PRECIPITATION SWITCHING TO SNOW MONDAY
NIGHT INTO TUESDAY. MAY WARM ENOUGH DURING THE DAY TUESDAY TO SEE
A SWITCH BACK TO RAIN/SNOW MIX IN THE SOUTH. LOW WILL PULL NORTH
INTO GREAT LAKES...WITH PRECIPITATION CHANCES LINGERING INTO
WEDNESDAY...ESPECIALLY IN THE NORTHEAST. GFS IS A BIT FASTER WITH
THE SYSTEM DEPARTING...AND MAY HAVE HELD ONTO POPS TOO LONG INTO
WEDNESDAY. BEHIND SYSTEM WINDS WILL INCREASE...AND MAY SEE BLOWING
OF ANY SNOW WHICH IS FALLING/FRESH FALLEN THROUGH WEDNESDAY WHICH
MAY CAUSE TRAVEL PROBLEMS AND WILL NEED TO CONTINUE TO MONITOR.

WILL SEE A BRIEF BREAK IN PRECIPITATION CHANCES FOR LATE IN THE
WEEK...PRIMARILY THURSDAY...BEFORE ANOTHER SYSTEM ARRIVES FOR THE
END OF THE WEEK. THERE IS STILL A LOT OF MODEL UNCERTAINTY WITH
THIS LATE SYSTEM...WITH GFS BRINGING SHORTWAVE ACROSS FRIDAY AND
ECMWF LIFTING SURFACE LOW ACROSS IOWA. MODEL DISCREPANCIES APPEAR
TO BE IN HANDLING OF EARLY WEEK LOW PRESSURE SYSTEM...WITH ECMWF
BEING MORE AGGRESSIVE IN LIFTING NORTH...WHILE GFS LINGERS
HELPING TO KEEP UPPER LEVEL TROUGH ACROSS IOWA. EITHER
WAY...PRECIPITATION WILL BE POSSIBLE...WITH TEMPERATURES COLD
ENOUGH FOR SNOW...AND WINDS MAY BE STRONG...CAPABLE OF BLOWING
SNOW. GAIN...WILL NEED TO CLOSELY WATCH SYSTEM...ESPECIALLY
EVOLUTION OF EARLY WEEK LOW.

&&

.AVIATION...20/06Z
ISSUED AT 1141 PM CST FRI DEC 19 2014

LOW STRATUS TO DOMINATE OVERNIGHT AND SATURDAY...RESULTING IN
MVFR CONDITIONS AND PERIODS OF IFR CONDITIONS ESPECIALLY PRIOR TO
SUNRISE. LIGHT TO MODERATE FOG ALSO LIKELY OVERNIGHT. DZ AND FZDZ
OVERNIGHT TURNING TO DZ BY LATE MORNING AND THE REST OF THE
PERIOD...ACCUMULATIONS WILL LIKELY NOT BE MEASURABLE.


&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...AWB
AVIATION...CURTIS





000
FXUS63 KDMX 200948
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
348 AM CST SAT DEC 20 2014

.SHORT TERM /TODAY/...
ISSUED AT 343 AM CST SAT DEC 20 2014

A COMPACT SHORT WAVE IS CURRENTLY MOVING ACROSS SOUTHWEST IOWA. LOW
LEVEL MOISTURE ADVECTION INITIALLY RESULTED IN AREAS OF FREEZING
DRIZZLE DURING THE EVENING HOWEVER MID LEVEL MOISTURE IMMEDIATELY IN
ADVANCE OF THE SHORT WAVE HAS BROUGHT AREAS OF ICE INTRODUCING AND
HAS SWITCHED THE PRECIPITATION TO VERY LIGHT SNOW AT TIMES.
SUBSIDENCE AND DRYING BEHIND THE SHORT WAVE WILL REMOVE THE ICE
INTRODUCTION AND WILL RETURN ANY PRECIPITATION BACK TO DRIZZLE OR
FREEZING DRIZZLE...DEPENDING ON THE SFC TEMPERATURES. THE MOST
FAVORED AREAS BETWEEN 6 AM AND NOON WILL BE ALONG AND EAST OF
INTERSTATE 35. A FEW ICY PATCHES WILL LIKELY DEVELOP ON ROADWAYS
THROUGH MID MORNING BUT DO NOT EXPECT MINOR ICE ACCUMULATIONS TO BE
WIDESPREAD ENOUGH TO WARRANT HEADLINES BUT MAY REQUIRE AN SPS FOR
MORNING TRAVEL. TEMPERATURES TODAY WILL AGAIN BE BELOW GUIDANCE AND
RELIANT ON MOISTURE ADVECTION WITH A THICK CLOUD SHIELD IN PLACE.
NOT MUCH CHANGE IN SFC DEWPOINTS THROUGH THE DAY WILL RELEGATE HIGHS
TO NEAR TO SLIGHTLY HIGHER THAN FRIDAYS TEMPERATURES.

.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 343 AM CST SAT DEC 20 2014

ACTIVE WEATHER PATTERN SETTING UP FOR EXTENDED...WITH MAIN
CONCERNS COMING AT BEGINNING AND END OF PERIOD. FOR BEGINNING OF
PERIOD...UPPER LEVEL TROUGH WILL KEEP SOUTHERLY FLOW AND MOISTURE
INCREASING ACROSS THE CWA. THIS MAY ALLOW FOR LIGHT PRECIPITATION
IN THE OVERNIGHT HOURS...ESPECIALLY AS FORCING ARRIVES NEAR 06Z.
NAM HAS FORCING FURTHER SOUTH...AND MAY NOT BE FAR ENOUGH SOUTH
WITH POPS. HOWEVER...MAIN CONCERN FOR OVERNIGHT AND INTO SUNDAY
WILL BE WITH PRECIPITATION TYPE. SURFACE TEMPERATURES WILL DROP
BELOW FREEZING IN THE NORTH...AND WITH SHALLOW LOW LEVEL MOISTURE
MAY NOT SEE ICE INTRODUCTION...LEADING TO FZDZ POTENTIAL.
HOWEVER...SOUNDINGS ALSO INDICATE UPPER LEVEL MOISTURE ARRIVING
LATE IN THE OVERNIGHT WHICH MAY HELP TO KEEP PRECIPITATION SN.
MODELS TRYING TO INDICATE SLEET...THOUGH HAVE KEPT MENTION OUT
ATTM WITH MELTING OF ANY ICE INTRODUCED UNLIKELY. THEREFORE HAVE
KEPT FZDZ MENTION IN THE NORTH/NORTHEAST...WITH DZ
ELSEWHERE...CHANGING TO RN/SN MIX IN THE EARLY MORNING HOURS
BEFORE SWITCHING BACK TO RAIN IN THE AFTERNOON SUNDAY. GIVEN
UNCERTAINTY IN PRECIPITATION TYPE AM NOT CONFIDENT ENOUGH TO ISSUE
ADVISORY ATTM...THOUGH WILL NEED TO BE MONITORED.

SURFACE LOW WILL PUSH INTO IOWA FOR LATE IN THE WEEKEND...KEEPING
PROLONGED PRECIPITATION CHANCES INTO EARLY NEXT WEEK. WILL SEE
PRIMARILY RAIN WITH SYSTEM AS TEMPERATURES WILL BE ABOVE
FREEZING. MODELS INDICATING DRY SLOT ACROSS MUCH OF CENTRAL IOWA
FOR MONDAY...AND HAVE CUT BACK ON POPS SLIGHTLY IN THE SOUTH
MONDAY. PRECIPITATION WILL RETURN WITH COLD AIR AS LOW PULLS
EAST...WHICH WILL SEE PRECIPITATION SWITCHING TO SNOW MONDAY
NIGHT INTO TUESDAY. MAY WARM ENOUGH DURING THE DAY TUESDAY TO SEE
A SWITCH BACK TO RAIN/SNOW MIX IN THE SOUTH. LOW WILL PULL NORTH
INTO GREAT LAKES...WITH PRECIPITATION CHANCES LINGERING INTO
WEDNESDAY...ESPECIALLY IN THE NORTHEAST. GFS IS A BIT FASTER WITH
THE SYSTEM DEPARTING...AND MAY HAVE HELD ONTO POPS TOO LONG INTO
WEDNESDAY. BEHIND SYSTEM WINDS WILL INCREASE...AND MAY SEE BLOWING
OF ANY SNOW WHICH IS FALLING/FRESH FALLEN THROUGH WEDNESDAY WHICH
MAY CAUSE TRAVEL PROBLEMS AND WILL NEED TO CONTINUE TO MONITOR.

WILL SEE A BRIEF BREAK IN PRECIPITATION CHANCES FOR LATE IN THE
WEEK...PRIMARILY THURSDAY...BEFORE ANOTHER SYSTEM ARRIVES FOR THE
END OF THE WEEK. THERE IS STILL A LOT OF MODEL UNCERTAINTY WITH
THIS LATE SYSTEM...WITH GFS BRINGING SHORTWAVE ACROSS FRIDAY AND
ECMWF LIFTING SURFACE LOW ACROSS IOWA. MODEL DISCREPANCIES APPEAR
TO BE IN HANDLING OF EARLY WEEK LOW PRESSURE SYSTEM...WITH ECMWF
BEING MORE AGGRESSIVE IN LIFTING NORTH...WHILE GFS LINGERS
HELPING TO KEEP UPPER LEVEL TROUGH ACROSS IOWA. EITHER
WAY...PRECIPITATION WILL BE POSSIBLE...WITH TEMPERATURES COLD
ENOUGH FOR SNOW...AND WINDS MAY BE STRONG...CAPABLE OF BLOWING
SNOW. GAIN...WILL NEED TO CLOSELY WATCH SYSTEM...ESPECIALLY
EVOLUTION OF EARLY WEEK LOW.

&&

.AVIATION...20/06Z
ISSUED AT 1141 PM CST FRI DEC 19 2014

LOW STRATUS TO DOMINATE OVERNIGHT AND SATURDAY...RESULTING IN
MVFR CONDITIONS AND PERIODS OF IFR CONDITIONS ESPECIALLY PRIOR TO
SUNRISE. LIGHT TO MODERATE FOG ALSO LIKELY OVERNIGHT. DZ AND FZDZ
OVERNIGHT TURNING TO DZ BY LATE MORNING AND THE REST OF THE
PERIOD...ACCUMULATIONS WILL LIKELY NOT BE MEASURABLE.


&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...AWB
AVIATION...CURTIS




000
FXUS63 KDMX 200551
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1151 PM CST FRI DEC 19 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 328 PM CST FRI DEC 19 2014

UPPER LEVEL TROUGH CURRENTLY ROTATING SOUTHEASTWARD THROUGH THE
WESTERN DAKOTAS ON WATER VAPOR...AND ALSO ANOTHER LITTLE WEAK
IMPULSE OF ENERGY LIFTING EASTWARD FROM THE HIGH PLAINS OF CO/NE.
BOTH OF THESE FEATURES TO MERGE AND PUSH ACROSS THE STATE
OVERNIGHT WITH WEAK WAA AND SOUTHERLY FLOW. WEAK ISENTROPIC LIFT
ALSO ACROSS THE CWA SO POTENTIAL FOR VERY LIGHT FREEZING DRIZZLE
OR FLURRIES IN PLACE MAINLY LATE TONIGHT. SOUNDINGS INDICATE MORE
OF A FREEZING DRIZZLE POTENTIAL...BUT TRY TO SHOW SOME SATURATION
ALOFT WHICH COULD LEAD TO A SEEDER FEEDER SITUATION CHANGING
PRECIP TO FLURRIES. WITH THE WEAK WAA AND INCREASING LOW LEVEL
MOISTURE...TEMPS WILL STAY RELATIVELY STEADY OVERNIGHT MAYBE ONLY
FALLING A FEW DEGREES AT MOST. PRECIP SHOULD REMAIN VERY LIGHT
WITH ONLY TRACE AMOUNTS EXPECTED...HOWEVER THE NAM KEEPS TRYING TO
SHOW SOME ENHANCEMENT IN A BAND OF PRECIP ASSOCIATED WITH THE WEAK
IMPULSE OF ENERGY LIFTING FROM THE HIGH PLAINS AND MERGING WITH
THE UPPER LOW DROPPING SOUTHEAST. THEREFORE WILL HAVE TO WATCH FOR
SOME PATCHES OF STEADIER PRECIP AT TIMES LATE TONIGHT AS THAT WAVE
MOVES THROUGH.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 328 PM CST FRI DEC 19 2014

SEVERAL FORECAST CONCERNS LEADING TO SOME POTENTIALLY SIGNIFICANT
TRAVEL ISSUES THIS WEEKEND INTO EARLY TO MID NEXT WEEK. LEANED
TOWARD THE NAM12/SREF/ECMWF THROUGH MONDAY AND THEN TOWARDS THE
ECMWF AS GFS SEEMS TO BE THE OUTLIER LATE IN THE PERIOD.

SATURDAY THROUGH MONDAY...WEAK WAA PERSISTS OVER THE WEEKEND AND
INTO MONDAY WITH A WEAK MID-LEVEL SHORTWAVE TO CUT ACROSS SOUTHERN
MINNESOTA AND NORTHERN IOWA LATE SATURDAY NIGHT INTO SUNDAY
MORNING. THE BEST FORCING REMAINS CONFINED IN THE AFOREMENTIONED
AREA FROM 06Z TO 18Z SUNDAY. IN THIS AREA...HIGHER CONFIDENCE WITH
FREEZING DRIZZLE OVER THE NORTH TO NORTHEAST AS SURFACE TEMPS LOOK
TO REMAIN BELOW FREEZING INTO SUNDAY MORNING. KEPT PATCHY FZDZ
OVER THE WEST-NORTHWEST B/T 06-12Z SUNDAY BEFORE SURFACE TEMPS
WARM TO ABOVE FREEZING AFTER SUNRISE. THERE IS A POTENTIAL FOR
SOME TRAVEL ISSUES OVER THE NORTHEAST EARLY SUNDAY MORNING AND MAY
WARRANT A SHORT-FUSED ADVISORY.

THE WAA CONTINUES THROUGHOUT THE DAY SUNDAY INTO MONDAY AFTERNOON
AND HAVE RAIN/DRIZZLE GOING OVER THE ENTIRE FORECAST AREA THROUGH
18Z MONDAY. THERE IS SOME DECENT FORCING WITHIN THE DENDRITIC LAYER
EARLY MONDAY MORNING BUT WITH THE WAA BELOW 850MB...THIS SHOULD BE
STRONG ENOUGH TO KEEP PRECIP ALL RAIN MONDAY AND TOOK OUT ANY
MENTION OF SLEET.

MONDAY NIGHT INTO WEDNESDAY...SURFACE LOW BEGINS TO TRACK EAST
ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA MONDAY EVENING INTO
EARLY TUESDAY AND BOTH THE GFS/ECMWF PLACE THE FORECAST AREA IN
THE DRY SLOT THROUGH 18Z TUESDAY. THUS...TRENDED TOWARD LOWERING
POPS ACROSS THE FORECAST AREA TO REFLECT THIS CHANGE MONDAY
EVENING AND TUESDAY. THE CAA IS SLOW TO DEVELOP MONDAY NIGHT AND
THE TRANSITION TO RAIN TO SNOW OVER THE WEST-NORTHWEST LOOKS TO BE
FROM 00-03Z TUESDAY AND FURTHER SOUTH AND EAST IN THE 03-09Z
TUESDAY TIME FRAME. HOWEVER...WITH THE LACK OF DEEP MOISTURE
PRESENT AND ANY SIGNIFICANT FORCING WITHIN THE DENDRITIC
LAYER...LOW CONFIDENCE WITH MEASURABLE SNOWFALL UNTIL TUESDAY
AFTERNOON/EVENING WHEN WRAP-AROUND MOISTURE PUSHES INTO THE
FORECAST AREA.

BETWEEN 00Z TO 12Z WEDNESDAY...THE DEEP MOISTURE PUSHES BACK INTO
NORTHERN IOWA AND THE NORTHWEST WINDS INCREASE SUBSTANTIALLY TOWARDS
WEDNESDAY MORNING. WINDS ATOP THE MIXED LAYER INCREASE TO AROUND 55
KNOTS AT MCW BY 18Z WEDNESDAY AND FORECAST SOUNDINGS STILL REMAIN
SATURATED IN THE SNOW GROWTH REGION DURING THE DAY WEDNESDAY.
POTENTIAL FOR SOME BLOWING SNOW/VISIBILITY RESTRICTIONS OVER
NORTHERN IOWA EVEN THOUGH NOT EXPECTING THE GOOD DENDRITIC TYPE
SNOW. REGARDLESS...INCREASED WINDS ON CHRISTMAS EVE AND MAY NEED
TO ADD BLOWING SNOW IF MODELS CONTINUE WITH THIS SCENARIO.

CHRISTMAS DAY AND FRIDAY...WEAK SURFACE HIGH LOOKS TO BUILD INTO THE
REGION ON CHRISTMAS APPEARS TO BE THE ONLY `QUIET` WEATHER DAY IN
THE EXTENDED. ECMWF HAS BEEN FAIRLY CONSISTENT BRINGING A STRONG
DEEP LOW TO PUNCH ACROSS THE REGION FRIDAY INTO SATURDAY. GFS
CONTINUES TO BOUNCE BACK AND FORTH BETWEEN INITIALIZATIONS...BUT
SOMETHING TO CONTINUE TO MONITOR AS WE GET CLOSER.

&&

.AVIATION...20/06Z
ISSUED AT 1141 PM CST FRI DEC 19 2014

LOW STRATUS TO DOMINATE OVERNIGHT AND SATURDAY...RESULTING IN
MVFR CONDITIONS AND PERIODS OF IFR CONDITIONS ESPECIALLY PRIOR TO
SUNRISE. LIGHT TO MODERATE FOG ALSO LIKELY OVERNIGHT. DZ AND FZDZ
OVERNIGHT TURNING TO DZ BY LATE MORNING AND THE REST OF THE
PERIOD...ACCUMULATIONS WILL LIKELY NOT BE MEASURABLE.

&&

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

$$

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




000
FXUS63 KDMX 200010
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
610 PM CST FRI DEC 19 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 328 PM CST FRI DEC 19 2014

UPPER LEVEL TROUGH CURRENTLY ROTATING SOUTHEASTWARD THROUGH THE
WESTERN DAKOTAS ON WATER VAPOR...AND ALSO ANOTHER LITTLE WEAK
IMPULSE OF ENERGY LIFTING EASTWARD FROM THE HIGH PLAINS OF CO/NE.
BOTH OF THESE FEATURES TO MERGE AND PUSH ACROSS THE STATE
OVERNIGHT WITH WEAK WAA AND SOUTHERLY FLOW. WEAK ISENTROPIC LIFT
ALSO ACROSS THE CWA SO POTENTIAL FOR VERY LIGHT FREEZING DRIZZLE
OR FLURRIES IN PLACE MAINLY LATE TONIGHT. SOUNDINGS INDICATE MORE
OF A FREEZING DRIZZLE POTENTIAL...BUT TRY TO SHOW SOME SATURATION
ALOFT WHICH COULD LEAD TO A SEEDER FEEDER SITUATION CHANGING
PRECIP TO FLURRIES. WITH THE WEAK WAA AND INCREASING LOW LEVEL
MOISTURE...TEMPS WILL STAY RELATIVELY STEADY OVERNIGHT MAYBE ONLY
FALLING A FEW DEGREES AT MOST. PRECIP SHOULD REMAIN VERY LIGHT
WITH ONLY TRACE AMOUNTS EXPECTED...HOWEVER THE NAM KEEPS TRYING TO
SHOW SOME ENHANCEMENT IN A BAND OF PRECIP ASSOCIATED WITH THE WEAK
IMPULSE OF ENERGY LIFTING FROM THE HIGH PLAINS AND MERGING WITH
THE UPPER LOW DROPPING SOUTHEAST. THEREFORE WILL HAVE TO WATCH FOR
SOME PATCHES OF STEADIER PRECIP AT TIMES LATE TONIGHT AS THAT WAVE
MOVES THROUGH.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 328 PM CST FRI DEC 19 2014

SEVERAL FORECAST CONCERNS LEADING TO SOME POTENTIALLY SIGNIFICANT
TRAVEL ISSUES THIS WEEKEND INTO EARLY TO MID NEXT WEEK. LEANED
TOWARD THE NAM12/SREF/ECMWF THROUGH MONDAY AND THEN TOWARDS THE
ECMWF AS GFS SEEMS TO BE THE OUTLIER LATE IN THE PERIOD.

SATURDAY THROUGH MONDAY...WEAK WAA PERSISTS OVER THE WEEKEND AND
INTO MONDAY WITH A WEAK MID-LEVEL SHORTWAVE TO CUT ACROSS SOUTHERN
MINNESOTA AND NORTHERN IOWA LATE SATURDAY NIGHT INTO SUNDAY
MORNING. THE BEST FORCING REMAINS CONFINED IN THE AFOREMENTIONED
AREA FROM 06Z TO 18Z SUNDAY. IN THIS AREA...HIGHER CONFIDENCE WITH
FREEZING DRIZZLE OVER THE NORTH TO NORTHEAST AS SURFACE TEMPS LOOK
TO REMAIN BELOW FREEZING INTO SUNDAY MORNING. KEPT PATCHY FZDZ
OVER THE WEST-NORTHWEST B/T 06-12Z SUNDAY BEFORE SURFACE TEMPS
WARM TO ABOVE FREEZING AFTER SUNRISE. THERE IS A POTENTIAL FOR
SOME TRAVEL ISSUES OVER THE NORTHEAST EARLY SUNDAY MORNING AND MAY
WARRANT A SHORT-FUSED ADVISORY.

THE WAA CONTINUES THROUGHOUT THE DAY SUNDAY INTO MONDAY AFTERNOON
AND HAVE RAIN/DRIZZLE GOING OVER THE ENTIRE FORECAST AREA THROUGH
18Z MONDAY. THERE IS SOME DECENT FORCING WITHIN THE DENDRITIC LAYER
EARLY MONDAY MORNING BUT WITH THE WAA BELOW 850MB...THIS SHOULD BE
STRONG ENOUGH TO KEEP PRECIP ALL RAIN MONDAY AND TOOK OUT ANY
MENTION OF SLEET.

MONDAY NIGHT INTO WEDNESDAY...SURFACE LOW BEGINS TO TRACK EAST
ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA MONDAY EVENING INTO
EARLY TUESDAY AND BOTH THE GFS/ECMWF PLACE THE FORECAST AREA IN
THE DRY SLOT THROUGH 18Z TUESDAY. THUS...TRENDED TOWARD LOWERING
POPS ACROSS THE FORECAST AREA TO REFLECT THIS CHANGE MONDAY
EVENING AND TUESDAY. THE CAA IS SLOW TO DEVELOP MONDAY NIGHT AND
THE TRANSITION TO RAIN TO SNOW OVER THE WEST-NORTHWEST LOOKS TO BE
FROM 00-03Z TUESDAY AND FURTHER SOUTH AND EAST IN THE 03-09Z
TUESDAY TIME FRAME. HOWEVER...WITH THE LACK OF DEEP MOISTURE
PRESENT AND ANY SIGNIFICANT FORCING WITHIN THE DENDRITIC
LAYER...LOW CONFIDENCE WITH MEASURABLE SNOWFALL UNTIL TUESDAY
AFTERNOON/EVENING WHEN WRAP-AROUND MOISTURE PUSHES INTO THE
FORECAST AREA.

BETWEEN 00Z TO 12Z WEDNESDAY...THE DEEP MOISTURE PUSHES BACK INTO
NORTHERN IOWA AND THE NORTHWEST WINDS INCREASE SUBSTANTIALLY TOWARDS
WEDNESDAY MORNING. WINDS ATOP THE MIXED LAYER INCREASE TO AROUND 55
KNOTS AT MCW BY 18Z WEDNESDAY AND FORECAST SOUNDINGS STILL REMAIN
SATURATED IN THE SNOW GROWTH REGION DURING THE DAY WEDNESDAY.
POTENTIAL FOR SOME BLOWING SNOW/VISIBILITY RESTRICTIONS OVER
NORTHERN IOWA EVEN THOUGH NOT EXPECTING THE GOOD DENDRITIC TYPE
SNOW. REGARDLESS...INCREASED WINDS ON CHRISTMAS EVE AND MAY NEED
TO ADD BLOWING SNOW IF MODELS CONTINUE WITH THIS SCENARIO.

CHRISTMAS DAY AND FRIDAY...WEAK SURFACE HIGH LOOKS TO BUILD INTO THE
REGION ON CHRISTMAS APPEARS TO BE THE ONLY `QUIET` WEATHER DAY IN
THE EXTENDED. ECMWF HAS BEEN FAIRLY CONSISTENT BRINGING A STRONG
DEEP LOW TO PUNCH ACROSS THE REGION FRIDAY INTO SATURDAY. GFS
CONTINUES TO BOUNCE BACK AND FORTH BETWEEN INITIALIZATIONS...BUT
SOMETHING TO CONTINUE TO MONITOR AS WE GET CLOSER.

&&

.AVIATION...20/00Z
ISSUED AT 609 PM CST FRI DEC 19 2014

LOW STATUS...LIGHT FOG AND FZDZ/DZ WILL CONTINUE ACROSS MUCH OF
CENTRAL IOWA TONIGHT INTO EARLY SATURDAY. THEREFORE...WIDESPREAD
MVFR TO IFR CONDITIONS WILL PERSIST STATEWIDE AT ALL SITES FOR
MUCH OF THE FORECAST. THERE WILL BE SOME IMPROVEMENT IN CEILING
HEIGHTS ON SATURDAY WITH DAYTIME HEATING...HOWEVER LEVELS LIKELY
TO REMAIN AT MVFR CONDITIONS. THE BEST THREAT OF FZDZ/DZ IN FAR
SOUTHEAST THIS EVENING AND THEN SPREADING WEST TO EAST LATE
TONIGHT AS WEAK WAVE TRAVERSES THE STATE. AMOUNTS TO BE VERY MINOR
AND IN MANY INSTANCES...NOT MEASURABLE.

&&

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

&&

$$

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





000
FXUS63 KDMX 200010
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
610 PM CST FRI DEC 19 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 328 PM CST FRI DEC 19 2014

UPPER LEVEL TROUGH CURRENTLY ROTATING SOUTHEASTWARD THROUGH THE
WESTERN DAKOTAS ON WATER VAPOR...AND ALSO ANOTHER LITTLE WEAK
IMPULSE OF ENERGY LIFTING EASTWARD FROM THE HIGH PLAINS OF CO/NE.
BOTH OF THESE FEATURES TO MERGE AND PUSH ACROSS THE STATE
OVERNIGHT WITH WEAK WAA AND SOUTHERLY FLOW. WEAK ISENTROPIC LIFT
ALSO ACROSS THE CWA SO POTENTIAL FOR VERY LIGHT FREEZING DRIZZLE
OR FLURRIES IN PLACE MAINLY LATE TONIGHT. SOUNDINGS INDICATE MORE
OF A FREEZING DRIZZLE POTENTIAL...BUT TRY TO SHOW SOME SATURATION
ALOFT WHICH COULD LEAD TO A SEEDER FEEDER SITUATION CHANGING
PRECIP TO FLURRIES. WITH THE WEAK WAA AND INCREASING LOW LEVEL
MOISTURE...TEMPS WILL STAY RELATIVELY STEADY OVERNIGHT MAYBE ONLY
FALLING A FEW DEGREES AT MOST. PRECIP SHOULD REMAIN VERY LIGHT
WITH ONLY TRACE AMOUNTS EXPECTED...HOWEVER THE NAM KEEPS TRYING TO
SHOW SOME ENHANCEMENT IN A BAND OF PRECIP ASSOCIATED WITH THE WEAK
IMPULSE OF ENERGY LIFTING FROM THE HIGH PLAINS AND MERGING WITH
THE UPPER LOW DROPPING SOUTHEAST. THEREFORE WILL HAVE TO WATCH FOR
SOME PATCHES OF STEADIER PRECIP AT TIMES LATE TONIGHT AS THAT WAVE
MOVES THROUGH.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 328 PM CST FRI DEC 19 2014

SEVERAL FORECAST CONCERNS LEADING TO SOME POTENTIALLY SIGNIFICANT
TRAVEL ISSUES THIS WEEKEND INTO EARLY TO MID NEXT WEEK. LEANED
TOWARD THE NAM12/SREF/ECMWF THROUGH MONDAY AND THEN TOWARDS THE
ECMWF AS GFS SEEMS TO BE THE OUTLIER LATE IN THE PERIOD.

SATURDAY THROUGH MONDAY...WEAK WAA PERSISTS OVER THE WEEKEND AND
INTO MONDAY WITH A WEAK MID-LEVEL SHORTWAVE TO CUT ACROSS SOUTHERN
MINNESOTA AND NORTHERN IOWA LATE SATURDAY NIGHT INTO SUNDAY
MORNING. THE BEST FORCING REMAINS CONFINED IN THE AFOREMENTIONED
AREA FROM 06Z TO 18Z SUNDAY. IN THIS AREA...HIGHER CONFIDENCE WITH
FREEZING DRIZZLE OVER THE NORTH TO NORTHEAST AS SURFACE TEMPS LOOK
TO REMAIN BELOW FREEZING INTO SUNDAY MORNING. KEPT PATCHY FZDZ
OVER THE WEST-NORTHWEST B/T 06-12Z SUNDAY BEFORE SURFACE TEMPS
WARM TO ABOVE FREEZING AFTER SUNRISE. THERE IS A POTENTIAL FOR
SOME TRAVEL ISSUES OVER THE NORTHEAST EARLY SUNDAY MORNING AND MAY
WARRANT A SHORT-FUSED ADVISORY.

THE WAA CONTINUES THROUGHOUT THE DAY SUNDAY INTO MONDAY AFTERNOON
AND HAVE RAIN/DRIZZLE GOING OVER THE ENTIRE FORECAST AREA THROUGH
18Z MONDAY. THERE IS SOME DECENT FORCING WITHIN THE DENDRITIC LAYER
EARLY MONDAY MORNING BUT WITH THE WAA BELOW 850MB...THIS SHOULD BE
STRONG ENOUGH TO KEEP PRECIP ALL RAIN MONDAY AND TOOK OUT ANY
MENTION OF SLEET.

MONDAY NIGHT INTO WEDNESDAY...SURFACE LOW BEGINS TO TRACK EAST
ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA MONDAY EVENING INTO
EARLY TUESDAY AND BOTH THE GFS/ECMWF PLACE THE FORECAST AREA IN
THE DRY SLOT THROUGH 18Z TUESDAY. THUS...TRENDED TOWARD LOWERING
POPS ACROSS THE FORECAST AREA TO REFLECT THIS CHANGE MONDAY
EVENING AND TUESDAY. THE CAA IS SLOW TO DEVELOP MONDAY NIGHT AND
THE TRANSITION TO RAIN TO SNOW OVER THE WEST-NORTHWEST LOOKS TO BE
FROM 00-03Z TUESDAY AND FURTHER SOUTH AND EAST IN THE 03-09Z
TUESDAY TIME FRAME. HOWEVER...WITH THE LACK OF DEEP MOISTURE
PRESENT AND ANY SIGNIFICANT FORCING WITHIN THE DENDRITIC
LAYER...LOW CONFIDENCE WITH MEASURABLE SNOWFALL UNTIL TUESDAY
AFTERNOON/EVENING WHEN WRAP-AROUND MOISTURE PUSHES INTO THE
FORECAST AREA.

BETWEEN 00Z TO 12Z WEDNESDAY...THE DEEP MOISTURE PUSHES BACK INTO
NORTHERN IOWA AND THE NORTHWEST WINDS INCREASE SUBSTANTIALLY TOWARDS
WEDNESDAY MORNING. WINDS ATOP THE MIXED LAYER INCREASE TO AROUND 55
KNOTS AT MCW BY 18Z WEDNESDAY AND FORECAST SOUNDINGS STILL REMAIN
SATURATED IN THE SNOW GROWTH REGION DURING THE DAY WEDNESDAY.
POTENTIAL FOR SOME BLOWING SNOW/VISIBILITY RESTRICTIONS OVER
NORTHERN IOWA EVEN THOUGH NOT EXPECTING THE GOOD DENDRITIC TYPE
SNOW. REGARDLESS...INCREASED WINDS ON CHRISTMAS EVE AND MAY NEED
TO ADD BLOWING SNOW IF MODELS CONTINUE WITH THIS SCENARIO.

CHRISTMAS DAY AND FRIDAY...WEAK SURFACE HIGH LOOKS TO BUILD INTO THE
REGION ON CHRISTMAS APPEARS TO BE THE ONLY `QUIET` WEATHER DAY IN
THE EXTENDED. ECMWF HAS BEEN FAIRLY CONSISTENT BRINGING A STRONG
DEEP LOW TO PUNCH ACROSS THE REGION FRIDAY INTO SATURDAY. GFS
CONTINUES TO BOUNCE BACK AND FORTH BETWEEN INITIALIZATIONS...BUT
SOMETHING TO CONTINUE TO MONITOR AS WE GET CLOSER.

&&

.AVIATION...20/00Z
ISSUED AT 609 PM CST FRI DEC 19 2014

LOW STATUS...LIGHT FOG AND FZDZ/DZ WILL CONTINUE ACROSS MUCH OF
CENTRAL IOWA TONIGHT INTO EARLY SATURDAY. THEREFORE...WIDESPREAD
MVFR TO IFR CONDITIONS WILL PERSIST STATEWIDE AT ALL SITES FOR
MUCH OF THE FORECAST. THERE WILL BE SOME IMPROVEMENT IN CEILING
HEIGHTS ON SATURDAY WITH DAYTIME HEATING...HOWEVER LEVELS LIKELY
TO REMAIN AT MVFR CONDITIONS. THE BEST THREAT OF FZDZ/DZ IN FAR
SOUTHEAST THIS EVENING AND THEN SPREADING WEST TO EAST LATE
TONIGHT AS WEAK WAVE TRAVERSES THE STATE. AMOUNTS TO BE VERY MINOR
AND IN MANY INSTANCES...NOT MEASURABLE.

&&

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

&&

$$

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




000
FXUS63 KDMX 192128
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
328 PM CST FRI DEC 19 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 328 PM CST FRI DEC 19 2014

UPPER LEVEL TROUGH CURRENTLY ROTATING SOUTHEASTWARD THROUGH THE
WESTERN DAKOTAS ON WATER VAPOR...AND ALSO ANOTHER LITTLE WEAK
IMPULSE OF ENERGY LIFTING EASTWARD FROM THE HIGH PLAINS OF CO/NE.
BOTH OF THESE FEATURES TO MERGE AND PUSH ACROSS THE STATE
OVERNIGHT WITH WEAK WAA AND SOUTHERLY FLOW. WEAK ISENTROPIC LIFT
ALSO ACROSS THE CWA SO POTENTIAL FOR VERY LIGHT FREEZING DRIZZLE
OR FLURRIES IN PLACE MAINLY LATE TONIGHT. SOUNDINGS INDICATE MORE
OF A FREEZING DRIZZLE POTENTIAL...BUT TRY TO SHOW SOME SATURATION
ALOFT WHICH COULD LEAD TO A SEEDER FEEDER SITUATION CHANGING
PRECIP TO FLURRIES. WITH THE WEAK WAA AND INCREASING LOW LEVEL
MOISTURE...TEMPS WILL STAY RELATIVELY STEADY OVERNIGHT MAYBE ONLY
FALLING A FEW DEGREES AT MOST. PRECIP SHOULD REMAIN VERY LIGHT
WITH ONLY TRACE AMOUNTS EXPECTED...HOWEVER THE NAM KEEPS TRYING TO
SHOW SOME ENHANCEMENT IN A BAND OF PRECIP ASSOCIATED WITH THE WEAK
IMPULSE OF ENERGY LIFTING FROM THE HIGH PLAINS AND MERGING WITH
THE UPPER LOW DROPPING SOUTHEAST. THEREFORE WILL HAVE TO WATCH FOR
SOME PATCHES OF STEADIER PRECIP AT TIMES LATE TONIGHT AS THAT WAVE
MOVES THROUGH.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 328 PM CST FRI DEC 19 2014

SEVERAL FORECAST CONCERNS LEADING TO SOME POTENTIALLY SIGNIFICANT
TRAVEL ISSUES THIS WEEKEND INTO EARLY TO MID NEXT WEEK. LEANED
TOWARD THE NAM12/SREF/ECMWF THROUGH MONDAY AND THEN TOWARDS THE
ECMWF AS GFS SEEMS TO BE THE OUTLIER LATE IN THE PERIOD.

SATURDAY THROUGH MONDAY...WEAK WAA PERSISTS OVER THE WEEKEND AND
INTO MONDAY WITH A WEAK MID-LEVEL SHORTWAVE TO CUT ACROSS SOUTHERN
MINNESOTA AND NORTHERN IOWA LATE SATURDAY NIGHT INTO SUNDAY
MORNING. THE BEST FORCING REMAINS CONFINED IN THE AFOREMENTIONED
AREA FROM 06Z TO 18Z SUNDAY. IN THIS AREA...HIGHER CONFIDENCE WITH
FREEZING DRIZZLE OVER THE NORTH TO NORTHEAST AS SURFACE TEMPS LOOK
TO REMAIN BELOW FREEZING INTO SUNDAY MORNING. KEPT PATCHY FZDZ
OVER THE WEST-NORTHWEST B/T 06-12Z SUNDAY BEFORE SURFACE TEMPS
WARM TO ABOVE FREEZING AFTER SUNRISE. THERE IS A POTENTIAL FOR
SOME TRAVEL ISSUES OVER THE NORTHEAST EARLY SUNDAY MORNING AND MAY
WARRANT A SHORT-FUSED ADVISORY.

THE WAA CONTINUES THROUGHOUT THE DAY SUNDAY INTO MONDAY AFTERNOON
AND HAVE RAIN/DRIZZLE GOING OVER THE ENTIRE FORECAST AREA THROUGH
18Z MONDAY. THERE IS SOME DECENT FORCING WITHIN THE DENDRITIC LAYER
EARLY MONDAY MORNING BUT WITH THE WAA BELOW 850MB...THIS SHOULD BE
STRONG ENOUGH TO KEEP PRECIP ALL RAIN MONDAY AND TOOK OUT ANY
MENTION OF SLEET.

MONDAY NIGHT INTO WEDNESDAY...SURFACE LOW BEGINS TO TRACK EAST
ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA MONDAY EVENING INTO
EARLY TUESDAY AND BOTH THE GFS/ECMWF PLACE THE FORECAST AREA IN
THE DRY SLOT THROUGH 18Z TUESDAY. THUS...TRENDED TOWARD LOWERING
POPS ACROSS THE FORECAST AREA TO REFLECT THIS CHANGE MONDAY
EVENING AND TUESDAY. THE CAA IS SLOW TO DEVELOP MONDAY NIGHT AND
THE TRANSITION TO RAIN TO SNOW OVER THE WEST-NORTHWEST LOOKS TO BE
FROM 00-03Z TUESDAY AND FURTHER SOUTH AND EAST IN THE 03-09Z
TUESDAY TIME FRAME. HOWEVER...WITH THE LACK OF DEEP MOISTURE
PRESENT AND ANY SIGNIFICANT FORCING WITHIN THE DENDRITIC
LAYER...LOW CONFIDENCE WITH MEASURABLE SNOWFALL UNTIL TUESDAY
AFTERNOON/EVENING WHEN WRAP-AROUND MOISTURE PUSHES INTO THE
FORECAST AREA.

BETWEEN 00Z TO 12Z WEDNESDAY...THE DEEP MOISTURE PUSHES BACK INTO
NORTHERN IOWA AND THE NORTHWEST WINDS INCREASE SUBSTANTIALLY TOWARDS
WEDNESDAY MORNING. WINDS ATOP THE MIXED LAYER INCREASE TO AROUND 55
KNOTS AT MCW BY 18Z WEDNESDAY AND FORECAST SOUNDINGS STILL REMAIN
SATURATED IN THE SNOW GROWTH REGION DURING THE DAY WEDNESDAY.
POTENTIAL FOR SOME BLOWING SNOW/VISIBILITY RESTRICTIONS OVER
NORTHERN IOWA EVEN THOUGH NOT EXPECTING THE GOOD DENDRITIC TYPE
SNOW. REGARDLESS...INCREASED WINDS ON CHRISTMAS EVE AND MAY NEED
TO ADD BLOWING SNOW IF MODELS CONTINUE WITH THIS SCENARIO.

CHRISTMAS DAY AND FRIDAY...WEAK SURFACE HIGH LOOKS TO BUILD INTO THE
REGION ON CHRISTMAS APPEARS TO BE THE ONLY `QUIET` WEATHER DAY IN
THE EXTENDED. ECMWF HAS BEEN FAIRLY CONSISTENT BRINGING A STRONG
DEEP LOW TO PUNCH ACROSS THE REGION FRIDAY INTO SATURDAY. GFS
CONTINUES TO BOUNCE BACK AND FORTH BETWEEN INITIALIZATIONS...BUT
SOMETHING TO CONTINUE TO MONITOR AS WE GET CLOSER.

&&

.AVIATION...19/18Z
ISSUED AT 1143 AM CST FRI DEC 19 2014

LOW CIGS CONTINUE TO BE AN ISSUE WITH SEVERAL LOCATIONS REPORTING
IFR CIGS AND MVFR VSBYS ACROSS THE AREA. LOW CIGS MAY LIFT SOME
THIS AFTERNOON TO MVFR...BUT ARE EXPECTED TO DROP AGAIN OVERNIGHT
TONIGHT. KOTM REMAINS VFR...BUT MAY LOWER THROUGHOUT THE PERIOD.
WINDS WILL REMAIN LIGHT OUT OF THE SOUTHEAST. OTHER ISSUE IS THE
POTENTIAL FOR VERY LIGHT FZDZ OR FLURRIES TONIGHT INTO EARLY
SATURDAY. STILL SOME UNCERTAINTY...BUT GIVEN THE CONDITIONS
PRODUCED SOME LIGHT PRECIP THIS MORNING AND LOOK EVEN BETTER
TONIGHT WILL LIKELY HAVE TO ADD A MENTION IN IN SUBSEQUENT TAF
ISSUANCES.


&&

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

&&

$$

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





000
FXUS63 KDMX 191743
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1143 AM CST FRI DEC 19 2014

.SHORT TERM /TODAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

LOW LEVEL MOISTURE SURGE IS LIFTING NORTHEAST ACROSS CENTRAL IOWA
THIS MORNING. WEAK FORCING WITHIN THIS SATURATED LAYER HAS PRODUCED
A MIX OF LIGHT FREEZING DRIZZLE OR FLURRIES WITH SATURATION TOPS
CURRENTLY BETWEEN -7C AND -9C WHICH IS ON THE EDGE BETWEEN GOOD ICE
INTRODUCTION AND SUPER COOLED DROPLETS. THE SATURATION DEPTHS
DECREASE FROM THE TOP OF THE LAYER THROUGH THE MORNING AND THUS
SHOULD DECREASE THE AMOUNT OF ICE INTRODUCTION WHICH WOULD LEAD TO
MORE FREEZING DRIZZLE PROCESSES. NOT EXPECTING A WIDESPREAD IMPACT
THOUGH LOCALIZED ICY PATCHES COULD OCCUR ON ROADWAYS AND WALKWAYS.
SKY CONDITIONS WILL REMAIN CLOUDY TODAY AND WILL HOLD TEMPERATURES
IN THE 20S TO LOWER 30S ONCE AGAIN.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

WE HAVE MUCH TO DISCUSS.

THIS WEEKEND WILL BE CHARACTERIZED BY GENERAL STRATUS AND
HAZE/FOG WITHIN A BROAD WARM AIR/MOISTURE ADVECTION REGIME IN
LIGHT SOUTHERLY SURFACE FLOW. THIS WILL ALSO LEAD TO A SLOW
WARMING TREND...WITH HIGH TEMPERATURES IN THE MID 30S TO LOWER 40S
BY SUNDAY. DURING THE NIGHTTIME AND EARLY MORNING HOURS...BOTH
FROM FRIDAY NIGHT INTO SATURDAY AND FROM SATURDAY NIGHT INTO
SUNDAY...THERE WILL BE INCREASING CHANCES FOR FOG AND DRIZZLE AS
THE NEAR SURFACE CLOUD LAYER GRADUALLY SATURATES AND DEEPENS. ON
FRIDAY NIGHT THE LAYER DEPTHS ARE STILL MARGINAL FOR DRIZZLE AND
THERE IS NO DISCERNIBLE SOURCE OF LIFT TO GENERATE THIS LIGHT
PRECIPITATION. HOWEVER...EVEN EARLY THIS MORNING /FRIDAY/ AND THE
PREVIOUS NIGHT WE HAVE SEEN PATCHY FREEZING DRIZZLE AROUND THE
AREA AND THE SATURATION...WHILE SHALLOW...SEEMS EVEN BETTER ON
FRIDAY NIGHT. GIVEN THE PERSISTENCE OF THE PATTERN...HAVE OPTED TO
INCLUDE DRIZZLE ACROSS THE AREA BETWEEN ABOUT MIDNIGHT AND
SUNRISE. TEMPERATURES WILL BE BELOW FREEZING DURING THIS PERIOD SO
ANY DRIZZLE THAT DOES FORM MAY CAUSE TRAVEL
IMPACTS...HOWEVER...CONFIDENCE IN OCCURRENCE IS EASILY TOO LOW TO
WARRANT ANY HEADLINE CONSIDERATION AT THIS TIME. ON SATURDAY NIGHT
A STRONG SURGE OF THETA E ADVECTION WILL MOVE ACROSS THE
AREA...MAINLY AFTER MIDNIGHT...WITH AN ATTENDANT INCREASE IN THE
DEPTH OF THE WARM CLOUD LAYER. THIS LEADS TO A CONSIDERABLY HIGHER
CONFIDENCE IN DRIZZLE OCCURRENCE LATE SATURDAY NIGHT INTO SUNDAY.
HOWEVER...BY THEN TEMPERATURES WILL BE NEAR OR ABOVE FREEZING IN
MANY AREAS SO IT IS DIFFICULT TO DIFFERENTIATE WHERE THE DRIZZLE
WILL FREEZE AND WHERE IT IS NOT...WITH THE BEST CHANCES FOR
FREEZING DRIZZLE ACROSS THE NORTHERN HALF OR SO OF THE FORECAST
AREA. COMPLICATING THIS FURTHER...FORECAST SOUNDINGS AND
CONCEPTUAL MODELS SUGGEST THAT THE ADVECTION SURGE THAT WILL
TRIGGER DRIZZLE GENERATION MAY PUSH TEMPERATURES FROM BELOW
FREEZING TO ABOVE FREEZING AND IT IS DIFFICULT TO TELL HOW QUICKLY
THIS WILL BE REFLECTED IN SURFACE/ROAD TEMPERATURES. IN ANY
EVENT...THOSE TRAVELING THIS WEEKEND SHOULD KEEP AN EYE ON THE
FORECAST FOR UPDATES ON THE POTENTIAL FOR FREEZING DRIZZLE DURING
THE NIGHTTIME/MORNING HOURS THIS WEEKEND.

BY SUNDAY NIGHT OUR MUCH ANTICIPATED LARGER STORM SYSTEM WILL BE
APPROACHING IN THE FORM OF A 500 MB SHORTWAVE AND ASSOCIATED
SURFACE LOW PRESSURE CENTER MOVING QUICKLY SOUTHEAST ACROSS THE
DAKOTAS. AS THIS SYSTEM REACHES IOWA WE WILL SEE PRECIPITATION
BREAK OUT ACROSS THE STATE FROM WEST TO EAST...MAINLY AFTER
MIDNIGHT SUNDAY NIGHT AND INTO MONDAY. TEMPERATURES WILL BE ABOVE
FREEZING LEADING TO RAIN ACROSS MOST OF THE AREA...WITH THE
EXCEPTION BEING IN OUR FAR NORTH WHERE TEMPERATURES NEAR FREEZING
MAY LEAD TO A WINTRY MIX OF PRECIPITATION BUT WITH LITTLE TO NO
SNOW OR ICE ACCUMULATION THROUGH MONDAY. THE STACKED LOW PRESSURE
CENTER SHOULD BE LOCATED OVER NORTHERN IOWA/SOUTHERN MINNESOTA BY
MONDAY NIGHT...THEREAFTER OCCLUDING AND MOVING SLOWLY TO THE EAST.
THIS WILL LEAD TO A RAIN TO SNOW TRANSITION FROM WEST TO EAST ON
MONDAY NIGHT...FOLLOWED BY A DAY OR TWO OF LIGHT SNOW WITHIN THE
LARGE CLOUD AND PRECIP SHIELD ON THE BACKSIDE OF THE SYSTEM. WHILE
CHANCES FOR SNOWFLAKES ARE HIGH ACROSS MUCH OF THE AREA FROM
MONDAY NIGHT THROUGH TUESDAY...GIVEN THAT THE LOW WILL BE SLOWLY
FILLING AND MOVING AWAY THE QPF IS FAIRLY LOW AND ANY SNOWFALL
AMOUNTS WILL PROBABLY BE LIGHT. THIS MAY STILL PRODUCE SOME TRAVEL
IMPACTS BUT THESE ARE VERY DIFFICULT TO DIAGNOSE AT THIS RANGE. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM IN THE COMING DAYS.

THE LIGHT SNOW TRAILING THE EARLY WEEK SYSTEM SHOULD CLEAR OUT OF
THE AREA ROUGHLY AROUND TUESDAY NIGHT OR POSSIBLY WEDNESDAY. IT
DOES APPEAR THAT ANOTHER STORM SYSTEM WILL APPROACH OUR AREA FROM
THE WEST LATE NEXT WEEK...JUST BEYOND THE CURRENT SEVEN DAY
FORECAST...WITH SOME CHANCE FOR PRECIPITATION POSSIBLY IN THE FORM
OF ADDITIONAL SNOWFALL.

&&

.AVIATION...19/18Z
ISSUED AT 1143 AM CST FRI DEC 19 2014

LOW CIGS CONTINUE TO BE AN ISSUE WITH SEVERAL LOCATIONS REPORTING
IFR CIGS AND MVFR VSBYS ACROSS THE AREA. LOW CIGS MAY LIFT SOME
THIS AFTERNOON TO MVFR...BUT ARE EXPECTED TO DROP AGAIN OVERNIGHT
TONIGHT. KOTM REMAINS VFR...BUT MAY LOWER THROUGHOUT THE PERIOD.
WINDS WILL REMAIN LIGHT OUT OF THE SOUTHEAST. OTHER ISSUE IS THE
POTENTIAL FOR VERY LIGHT FZDZ OR FLURRIES TONIGHT INTO EARLY
SATURDAY. STILL SOME UNCERTAINTY...BUT GIVEN THE CONDITIONS
PRODUCED SOME LIGHT PRECIP THIS MORNING AND LOOK EVEN BETTER
TONIGHT WILL LIKELY HAVE TO ADD A MENTION IN IN SUBSEQUENT TAF
ISSUANCES.

&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...BEERENDS




000
FXUS63 KDMX 191743
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1143 AM CST FRI DEC 19 2014

.SHORT TERM /TODAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

LOW LEVEL MOISTURE SURGE IS LIFTING NORTHEAST ACROSS CENTRAL IOWA
THIS MORNING. WEAK FORCING WITHIN THIS SATURATED LAYER HAS PRODUCED
A MIX OF LIGHT FREEZING DRIZZLE OR FLURRIES WITH SATURATION TOPS
CURRENTLY BETWEEN -7C AND -9C WHICH IS ON THE EDGE BETWEEN GOOD ICE
INTRODUCTION AND SUPER COOLED DROPLETS. THE SATURATION DEPTHS
DECREASE FROM THE TOP OF THE LAYER THROUGH THE MORNING AND THUS
SHOULD DECREASE THE AMOUNT OF ICE INTRODUCTION WHICH WOULD LEAD TO
MORE FREEZING DRIZZLE PROCESSES. NOT EXPECTING A WIDESPREAD IMPACT
THOUGH LOCALIZED ICY PATCHES COULD OCCUR ON ROADWAYS AND WALKWAYS.
SKY CONDITIONS WILL REMAIN CLOUDY TODAY AND WILL HOLD TEMPERATURES
IN THE 20S TO LOWER 30S ONCE AGAIN.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

WE HAVE MUCH TO DISCUSS.

THIS WEEKEND WILL BE CHARACTERIZED BY GENERAL STRATUS AND
HAZE/FOG WITHIN A BROAD WARM AIR/MOISTURE ADVECTION REGIME IN
LIGHT SOUTHERLY SURFACE FLOW. THIS WILL ALSO LEAD TO A SLOW
WARMING TREND...WITH HIGH TEMPERATURES IN THE MID 30S TO LOWER 40S
BY SUNDAY. DURING THE NIGHTTIME AND EARLY MORNING HOURS...BOTH
FROM FRIDAY NIGHT INTO SATURDAY AND FROM SATURDAY NIGHT INTO
SUNDAY...THERE WILL BE INCREASING CHANCES FOR FOG AND DRIZZLE AS
THE NEAR SURFACE CLOUD LAYER GRADUALLY SATURATES AND DEEPENS. ON
FRIDAY NIGHT THE LAYER DEPTHS ARE STILL MARGINAL FOR DRIZZLE AND
THERE IS NO DISCERNIBLE SOURCE OF LIFT TO GENERATE THIS LIGHT
PRECIPITATION. HOWEVER...EVEN EARLY THIS MORNING /FRIDAY/ AND THE
PREVIOUS NIGHT WE HAVE SEEN PATCHY FREEZING DRIZZLE AROUND THE
AREA AND THE SATURATION...WHILE SHALLOW...SEEMS EVEN BETTER ON
FRIDAY NIGHT. GIVEN THE PERSISTENCE OF THE PATTERN...HAVE OPTED TO
INCLUDE DRIZZLE ACROSS THE AREA BETWEEN ABOUT MIDNIGHT AND
SUNRISE. TEMPERATURES WILL BE BELOW FREEZING DURING THIS PERIOD SO
ANY DRIZZLE THAT DOES FORM MAY CAUSE TRAVEL
IMPACTS...HOWEVER...CONFIDENCE IN OCCURRENCE IS EASILY TOO LOW TO
WARRANT ANY HEADLINE CONSIDERATION AT THIS TIME. ON SATURDAY NIGHT
A STRONG SURGE OF THETA E ADVECTION WILL MOVE ACROSS THE
AREA...MAINLY AFTER MIDNIGHT...WITH AN ATTENDANT INCREASE IN THE
DEPTH OF THE WARM CLOUD LAYER. THIS LEADS TO A CONSIDERABLY HIGHER
CONFIDENCE IN DRIZZLE OCCURRENCE LATE SATURDAY NIGHT INTO SUNDAY.
HOWEVER...BY THEN TEMPERATURES WILL BE NEAR OR ABOVE FREEZING IN
MANY AREAS SO IT IS DIFFICULT TO DIFFERENTIATE WHERE THE DRIZZLE
WILL FREEZE AND WHERE IT IS NOT...WITH THE BEST CHANCES FOR
FREEZING DRIZZLE ACROSS THE NORTHERN HALF OR SO OF THE FORECAST
AREA. COMPLICATING THIS FURTHER...FORECAST SOUNDINGS AND
CONCEPTUAL MODELS SUGGEST THAT THE ADVECTION SURGE THAT WILL
TRIGGER DRIZZLE GENERATION MAY PUSH TEMPERATURES FROM BELOW
FREEZING TO ABOVE FREEZING AND IT IS DIFFICULT TO TELL HOW QUICKLY
THIS WILL BE REFLECTED IN SURFACE/ROAD TEMPERATURES. IN ANY
EVENT...THOSE TRAVELING THIS WEEKEND SHOULD KEEP AN EYE ON THE
FORECAST FOR UPDATES ON THE POTENTIAL FOR FREEZING DRIZZLE DURING
THE NIGHTTIME/MORNING HOURS THIS WEEKEND.

BY SUNDAY NIGHT OUR MUCH ANTICIPATED LARGER STORM SYSTEM WILL BE
APPROACHING IN THE FORM OF A 500 MB SHORTWAVE AND ASSOCIATED
SURFACE LOW PRESSURE CENTER MOVING QUICKLY SOUTHEAST ACROSS THE
DAKOTAS. AS THIS SYSTEM REACHES IOWA WE WILL SEE PRECIPITATION
BREAK OUT ACROSS THE STATE FROM WEST TO EAST...MAINLY AFTER
MIDNIGHT SUNDAY NIGHT AND INTO MONDAY. TEMPERATURES WILL BE ABOVE
FREEZING LEADING TO RAIN ACROSS MOST OF THE AREA...WITH THE
EXCEPTION BEING IN OUR FAR NORTH WHERE TEMPERATURES NEAR FREEZING
MAY LEAD TO A WINTRY MIX OF PRECIPITATION BUT WITH LITTLE TO NO
SNOW OR ICE ACCUMULATION THROUGH MONDAY. THE STACKED LOW PRESSURE
CENTER SHOULD BE LOCATED OVER NORTHERN IOWA/SOUTHERN MINNESOTA BY
MONDAY NIGHT...THEREAFTER OCCLUDING AND MOVING SLOWLY TO THE EAST.
THIS WILL LEAD TO A RAIN TO SNOW TRANSITION FROM WEST TO EAST ON
MONDAY NIGHT...FOLLOWED BY A DAY OR TWO OF LIGHT SNOW WITHIN THE
LARGE CLOUD AND PRECIP SHIELD ON THE BACKSIDE OF THE SYSTEM. WHILE
CHANCES FOR SNOWFLAKES ARE HIGH ACROSS MUCH OF THE AREA FROM
MONDAY NIGHT THROUGH TUESDAY...GIVEN THAT THE LOW WILL BE SLOWLY
FILLING AND MOVING AWAY THE QPF IS FAIRLY LOW AND ANY SNOWFALL
AMOUNTS WILL PROBABLY BE LIGHT. THIS MAY STILL PRODUCE SOME TRAVEL
IMPACTS BUT THESE ARE VERY DIFFICULT TO DIAGNOSE AT THIS RANGE. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM IN THE COMING DAYS.

THE LIGHT SNOW TRAILING THE EARLY WEEK SYSTEM SHOULD CLEAR OUT OF
THE AREA ROUGHLY AROUND TUESDAY NIGHT OR POSSIBLY WEDNESDAY. IT
DOES APPEAR THAT ANOTHER STORM SYSTEM WILL APPROACH OUR AREA FROM
THE WEST LATE NEXT WEEK...JUST BEYOND THE CURRENT SEVEN DAY
FORECAST...WITH SOME CHANCE FOR PRECIPITATION POSSIBLY IN THE FORM
OF ADDITIONAL SNOWFALL.

&&

.AVIATION...19/18Z
ISSUED AT 1143 AM CST FRI DEC 19 2014

LOW CIGS CONTINUE TO BE AN ISSUE WITH SEVERAL LOCATIONS REPORTING
IFR CIGS AND MVFR VSBYS ACROSS THE AREA. LOW CIGS MAY LIFT SOME
THIS AFTERNOON TO MVFR...BUT ARE EXPECTED TO DROP AGAIN OVERNIGHT
TONIGHT. KOTM REMAINS VFR...BUT MAY LOWER THROUGHOUT THE PERIOD.
WINDS WILL REMAIN LIGHT OUT OF THE SOUTHEAST. OTHER ISSUE IS THE
POTENTIAL FOR VERY LIGHT FZDZ OR FLURRIES TONIGHT INTO EARLY
SATURDAY. STILL SOME UNCERTAINTY...BUT GIVEN THE CONDITIONS
PRODUCED SOME LIGHT PRECIP THIS MORNING AND LOOK EVEN BETTER
TONIGHT WILL LIKELY HAVE TO ADD A MENTION IN IN SUBSEQUENT TAF
ISSUANCES.

&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...BEERENDS





000
FXUS63 KDMX 191135
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
535 AM CST FRI DEC 19 2014

.SHORT TERM /TODAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

LOW LEVEL MOISTURE SURGE IS LIFTING NORTHEAST ACROSS CENTRAL IOWA
THIS MORNING. WEAK FORCING WITHIN THIS SATURATED LAYER HAS PRODUCED
A MIX OF LIGHT FREEZING DRIZZLE OR FLURRIES WITH SATURATION TOPS
CURRENTLY BETWEEN -7C AND -9C WHICH IS ON THE EDGE BETWEEN GOOD ICE
INTRODUCTION AND SUPER COOLED DROPLETS. THE SATURATION DEPTHS
DECREASE FROM THE TOP OF THE LAYER THROUGH THE MORNING AND THUS
SHOULD DECREASE THE AMOUNT OF ICE INTRODUCTION WHICH WOULD LEAD TO
MORE FREEZING DRIZZLE PROCESSES. NOT EXPECTING A WIDESPREAD IMPACT
THOUGH LOCALIZED ICY PATCHES COULD OCCUR ON ROADWAYS AND WALKWAYS.
SKY CONDITIONS WILL REMAIN CLOUDY TODAY AND WILL HOLD TEMPERATURES
IN THE 20S TO LOWER 30S ONCE AGAIN.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

WE HAVE MUCH TO DISCUSS.

THIS WEEKEND WILL BE CHARACTERIZED BY GENERAL STRATUS AND
HAZE/FOG WITHIN A BROAD WARM AIR/MOISTURE ADVECTION REGIME IN
LIGHT SOUTHERLY SURFACE FLOW. THIS WILL ALSO LEAD TO A SLOW
WARMING TREND...WITH HIGH TEMPERATURES IN THE MID 30S TO LOWER 40S
BY SUNDAY. DURING THE NIGHTTIME AND EARLY MORNING HOURS...BOTH
FROM FRIDAY NIGHT INTO SATURDAY AND FROM SATURDAY NIGHT INTO
SUNDAY...THERE WILL BE INCREASING CHANCES FOR FOG AND DRIZZLE AS
THE NEAR SURFACE CLOUD LAYER GRADUALLY SATURATES AND DEEPENS. ON
FRIDAY NIGHT THE LAYER DEPTHS ARE STILL MARGINAL FOR DRIZZLE AND
THERE IS NO DISCERNIBLE SOURCE OF LIFT TO GENERATE THIS LIGHT
PRECIPITATION. HOWEVER...EVEN EARLY THIS MORNING /FRIDAY/ AND THE
PREVIOUS NIGHT WE HAVE SEEN PATCHY FREEZING DRIZZLE AROUND THE
AREA AND THE SATURATION...WHILE SHALLOW...SEEMS EVEN BETTER ON
FRIDAY NIGHT. GIVEN THE PERSISTENCE OF THE PATTERN...HAVE OPTED TO
INCLUDE DRIZZLE ACROSS THE AREA BETWEEN ABOUT MIDNIGHT AND
SUNRISE. TEMPERATURES WILL BE BELOW FREEZING DURING THIS PERIOD SO
ANY DRIZZLE THAT DOES FORM MAY CAUSE TRAVEL
IMPACTS...HOWEVER...CONFIDENCE IN OCCURRENCE IS EASILY TOO LOW TO
WARRANT ANY HEADLINE CONSIDERATION AT THIS TIME. ON SATURDAY NIGHT
A STRONG SURGE OF THETA E ADVECTION WILL MOVE ACROSS THE
AREA...MAINLY AFTER MIDNIGHT...WITH AN ATTENDANT INCREASE IN THE
DEPTH OF THE WARM CLOUD LAYER. THIS LEADS TO A CONSIDERABLY HIGHER
CONFIDENCE IN DRIZZLE OCCURRENCE LATE SATURDAY NIGHT INTO SUNDAY.
HOWEVER...BY THEN TEMPERATURES WILL BE NEAR OR ABOVE FREEZING IN
MANY AREAS SO IT IS DIFFICULT TO DIFFERENTIATE WHERE THE DRIZZLE
WILL FREEZE AND WHERE IT IS NOT...WITH THE BEST CHANCES FOR
FREEZING DRIZZLE ACROSS THE NORTHERN HALF OR SO OF THE FORECAST
AREA. COMPLICATING THIS FURTHER...FORECAST SOUNDINGS AND
CONCEPTUAL MODELS SUGGEST THAT THE ADVECTION SURGE THAT WILL
TRIGGER DRIZZLE GENERATION MAY PUSH TEMPERATURES FROM BELOW
FREEZING TO ABOVE FREEZING AND IT IS DIFFICULT TO TELL HOW QUICKLY
THIS WILL BE REFLECTED IN SURFACE/ROAD TEMPERATURES. IN ANY
EVENT...THOSE TRAVELING THIS WEEKEND SHOULD KEEP AN EYE ON THE
FORECAST FOR UPDATES ON THE POTENTIAL FOR FREEZING DRIZZLE DURING
THE NIGHTTIME/MORNING HOURS THIS WEEKEND.

BY SUNDAY NIGHT OUR MUCH ANTICIPATED LARGER STORM SYSTEM WILL BE
APPROACHING IN THE FORM OF A 500 MB SHORTWAVE AND ASSOCIATED
SURFACE LOW PRESSURE CENTER MOVING QUICKLY SOUTHEAST ACROSS THE
DAKOTAS. AS THIS SYSTEM REACHES IOWA WE WILL SEE PRECIPITATION
BREAK OUT ACROSS THE STATE FROM WEST TO EAST...MAINLY AFTER
MIDNIGHT SUNDAY NIGHT AND INTO MONDAY. TEMPERATURES WILL BE ABOVE
FREEZING LEADING TO RAIN ACROSS MOST OF THE AREA...WITH THE
EXCEPTION BEING IN OUR FAR NORTH WHERE TEMPERATURES NEAR FREEZING
MAY LEAD TO A WINTRY MIX OF PRECIPITATION BUT WITH LITTLE TO NO
SNOW OR ICE ACCUMULATION THROUGH MONDAY. THE STACKED LOW PRESSURE
CENTER SHOULD BE LOCATED OVER NORTHERN IOWA/SOUTHERN MINNESOTA BY
MONDAY NIGHT...THEREAFTER OCCLUDING AND MOVING SLOWLY TO THE EAST.
THIS WILL LEAD TO A RAIN TO SNOW TRANSITION FROM WEST TO EAST ON
MONDAY NIGHT...FOLLOWED BY A DAY OR TWO OF LIGHT SNOW WITHIN THE
LARGE CLOUD AND PRECIP SHIELD ON THE BACKSIDE OF THE SYSTEM. WHILE
CHANCES FOR SNOWFLAKES ARE HIGH ACROSS MUCH OF THE AREA FROM
MONDAY NIGHT THROUGH TUESDAY...GIVEN THAT THE LOW WILL BE SLOWLY
FILLING AND MOVING AWAY THE QPF IS FAIRLY LOW AND ANY SNOWFALL
AMOUNTS WILL PROBABLY BE LIGHT. THIS MAY STILL PRODUCE SOME TRAVEL
IMPACTS BUT THESE ARE VERY DIFFICULT TO DIAGNOSE AT THIS RANGE. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM IN THE COMING DAYS.

THE LIGHT SNOW TRAILING THE EARLY WEEK SYSTEM SHOULD CLEAR OUT OF
THE AREA ROUGHLY AROUND TUESDAY NIGHT OR POSSIBLY WEDNESDAY. IT
DOES APPEAR THAT ANOTHER STORM SYSTEM WILL APPROACH OUR AREA FROM
THE WEST LATE NEXT WEEK...JUST BEYOND THE CURRENT SEVEN DAY
FORECAST...WITH SOME CHANCE FOR PRECIPITATION POSSIBLY IN THE FORM
OF ADDITIONAL SNOWFALL.

&&

.AVIATION...19/12Z
ISSUED AT 535 AM CST FRI DEC 19 2014

WIDESPREAD IFR/MVFR STRATUS WILL PERSIST THROUGH MUCH OF THE
PERIOD. THE IFR STRATUS OVER SW IA IS EXPECTED TO SPREAD NORTHEAST
TODAY THROUGH IT SHOULD RAISE A BIT THIS AFTERNOON AND BECOME
BORDERLINE MVFR. PATCHES OF DRIZZLE OR FOG POSSIBLE THROUGH THE
PERIOD BUT SHOULD NOT BE A BIG IMPACT. WINDS WILL REMAIN LIGHT OUT
OF THE SOUTH TO SOUTHEAST.

&&

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

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DONAVON




000
FXUS63 KDMX 191135
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
535 AM CST FRI DEC 19 2014

.SHORT TERM /TODAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

LOW LEVEL MOISTURE SURGE IS LIFTING NORTHEAST ACROSS CENTRAL IOWA
THIS MORNING. WEAK FORCING WITHIN THIS SATURATED LAYER HAS PRODUCED
A MIX OF LIGHT FREEZING DRIZZLE OR FLURRIES WITH SATURATION TOPS
CURRENTLY BETWEEN -7C AND -9C WHICH IS ON THE EDGE BETWEEN GOOD ICE
INTRODUCTION AND SUPER COOLED DROPLETS. THE SATURATION DEPTHS
DECREASE FROM THE TOP OF THE LAYER THROUGH THE MORNING AND THUS
SHOULD DECREASE THE AMOUNT OF ICE INTRODUCTION WHICH WOULD LEAD TO
MORE FREEZING DRIZZLE PROCESSES. NOT EXPECTING A WIDESPREAD IMPACT
THOUGH LOCALIZED ICY PATCHES COULD OCCUR ON ROADWAYS AND WALKWAYS.
SKY CONDITIONS WILL REMAIN CLOUDY TODAY AND WILL HOLD TEMPERATURES
IN THE 20S TO LOWER 30S ONCE AGAIN.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

WE HAVE MUCH TO DISCUSS.

THIS WEEKEND WILL BE CHARACTERIZED BY GENERAL STRATUS AND
HAZE/FOG WITHIN A BROAD WARM AIR/MOISTURE ADVECTION REGIME IN
LIGHT SOUTHERLY SURFACE FLOW. THIS WILL ALSO LEAD TO A SLOW
WARMING TREND...WITH HIGH TEMPERATURES IN THE MID 30S TO LOWER 40S
BY SUNDAY. DURING THE NIGHTTIME AND EARLY MORNING HOURS...BOTH
FROM FRIDAY NIGHT INTO SATURDAY AND FROM SATURDAY NIGHT INTO
SUNDAY...THERE WILL BE INCREASING CHANCES FOR FOG AND DRIZZLE AS
THE NEAR SURFACE CLOUD LAYER GRADUALLY SATURATES AND DEEPENS. ON
FRIDAY NIGHT THE LAYER DEPTHS ARE STILL MARGINAL FOR DRIZZLE AND
THERE IS NO DISCERNIBLE SOURCE OF LIFT TO GENERATE THIS LIGHT
PRECIPITATION. HOWEVER...EVEN EARLY THIS MORNING /FRIDAY/ AND THE
PREVIOUS NIGHT WE HAVE SEEN PATCHY FREEZING DRIZZLE AROUND THE
AREA AND THE SATURATION...WHILE SHALLOW...SEEMS EVEN BETTER ON
FRIDAY NIGHT. GIVEN THE PERSISTENCE OF THE PATTERN...HAVE OPTED TO
INCLUDE DRIZZLE ACROSS THE AREA BETWEEN ABOUT MIDNIGHT AND
SUNRISE. TEMPERATURES WILL BE BELOW FREEZING DURING THIS PERIOD SO
ANY DRIZZLE THAT DOES FORM MAY CAUSE TRAVEL
IMPACTS...HOWEVER...CONFIDENCE IN OCCURRENCE IS EASILY TOO LOW TO
WARRANT ANY HEADLINE CONSIDERATION AT THIS TIME. ON SATURDAY NIGHT
A STRONG SURGE OF THETA E ADVECTION WILL MOVE ACROSS THE
AREA...MAINLY AFTER MIDNIGHT...WITH AN ATTENDANT INCREASE IN THE
DEPTH OF THE WARM CLOUD LAYER. THIS LEADS TO A CONSIDERABLY HIGHER
CONFIDENCE IN DRIZZLE OCCURRENCE LATE SATURDAY NIGHT INTO SUNDAY.
HOWEVER...BY THEN TEMPERATURES WILL BE NEAR OR ABOVE FREEZING IN
MANY AREAS SO IT IS DIFFICULT TO DIFFERENTIATE WHERE THE DRIZZLE
WILL FREEZE AND WHERE IT IS NOT...WITH THE BEST CHANCES FOR
FREEZING DRIZZLE ACROSS THE NORTHERN HALF OR SO OF THE FORECAST
AREA. COMPLICATING THIS FURTHER...FORECAST SOUNDINGS AND
CONCEPTUAL MODELS SUGGEST THAT THE ADVECTION SURGE THAT WILL
TRIGGER DRIZZLE GENERATION MAY PUSH TEMPERATURES FROM BELOW
FREEZING TO ABOVE FREEZING AND IT IS DIFFICULT TO TELL HOW QUICKLY
THIS WILL BE REFLECTED IN SURFACE/ROAD TEMPERATURES. IN ANY
EVENT...THOSE TRAVELING THIS WEEKEND SHOULD KEEP AN EYE ON THE
FORECAST FOR UPDATES ON THE POTENTIAL FOR FREEZING DRIZZLE DURING
THE NIGHTTIME/MORNING HOURS THIS WEEKEND.

BY SUNDAY NIGHT OUR MUCH ANTICIPATED LARGER STORM SYSTEM WILL BE
APPROACHING IN THE FORM OF A 500 MB SHORTWAVE AND ASSOCIATED
SURFACE LOW PRESSURE CENTER MOVING QUICKLY SOUTHEAST ACROSS THE
DAKOTAS. AS THIS SYSTEM REACHES IOWA WE WILL SEE PRECIPITATION
BREAK OUT ACROSS THE STATE FROM WEST TO EAST...MAINLY AFTER
MIDNIGHT SUNDAY NIGHT AND INTO MONDAY. TEMPERATURES WILL BE ABOVE
FREEZING LEADING TO RAIN ACROSS MOST OF THE AREA...WITH THE
EXCEPTION BEING IN OUR FAR NORTH WHERE TEMPERATURES NEAR FREEZING
MAY LEAD TO A WINTRY MIX OF PRECIPITATION BUT WITH LITTLE TO NO
SNOW OR ICE ACCUMULATION THROUGH MONDAY. THE STACKED LOW PRESSURE
CENTER SHOULD BE LOCATED OVER NORTHERN IOWA/SOUTHERN MINNESOTA BY
MONDAY NIGHT...THEREAFTER OCCLUDING AND MOVING SLOWLY TO THE EAST.
THIS WILL LEAD TO A RAIN TO SNOW TRANSITION FROM WEST TO EAST ON
MONDAY NIGHT...FOLLOWED BY A DAY OR TWO OF LIGHT SNOW WITHIN THE
LARGE CLOUD AND PRECIP SHIELD ON THE BACKSIDE OF THE SYSTEM. WHILE
CHANCES FOR SNOWFLAKES ARE HIGH ACROSS MUCH OF THE AREA FROM
MONDAY NIGHT THROUGH TUESDAY...GIVEN THAT THE LOW WILL BE SLOWLY
FILLING AND MOVING AWAY THE QPF IS FAIRLY LOW AND ANY SNOWFALL
AMOUNTS WILL PROBABLY BE LIGHT. THIS MAY STILL PRODUCE SOME TRAVEL
IMPACTS BUT THESE ARE VERY DIFFICULT TO DIAGNOSE AT THIS RANGE. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM IN THE COMING DAYS.

THE LIGHT SNOW TRAILING THE EARLY WEEK SYSTEM SHOULD CLEAR OUT OF
THE AREA ROUGHLY AROUND TUESDAY NIGHT OR POSSIBLY WEDNESDAY. IT
DOES APPEAR THAT ANOTHER STORM SYSTEM WILL APPROACH OUR AREA FROM
THE WEST LATE NEXT WEEK...JUST BEYOND THE CURRENT SEVEN DAY
FORECAST...WITH SOME CHANCE FOR PRECIPITATION POSSIBLY IN THE FORM
OF ADDITIONAL SNOWFALL.

&&

.AVIATION...19/12Z
ISSUED AT 535 AM CST FRI DEC 19 2014

WIDESPREAD IFR/MVFR STRATUS WILL PERSIST THROUGH MUCH OF THE
PERIOD. THE IFR STRATUS OVER SW IA IS EXPECTED TO SPREAD NORTHEAST
TODAY THROUGH IT SHOULD RAISE A BIT THIS AFTERNOON AND BECOME
BORDERLINE MVFR. PATCHES OF DRIZZLE OR FOG POSSIBLE THROUGH THE
PERIOD BUT SHOULD NOT BE A BIG IMPACT. WINDS WILL REMAIN LIGHT OUT
OF THE SOUTH TO SOUTHEAST.

&&

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

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DONAVON





000
FXUS63 KDMX 190929
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
329 AM CST FRI DEC 19 2014

.SHORT TERM /TODAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

LOW LEVEL MOISTURE SURGE IS LIFTING NORTHEAST ACROSS CENTRAL IOWA
THIS MORNING. WEAK FORCING WITHIN THIS SATURATED LAYER HAS PRODUCED
A MIX OF LIGHT FREEZING DRIZZLE OR FLURRIES WITH SATURATION TOPS
CURRENTLY BETWEEN -7C AND -9C WHICH IS ON THE EDGE BETWEEN GOOD ICE
INTRODUCTION AND SUPER COOLED DROPLETS. THE SATURATION DEPTHS
DECREASE FROM THE TOP OF THE LAYER THROUGH THE MORNING AND THUS
SHOULD DECREASE THE AMOUNT OF ICE INTRODUCTION WHICH WOULD LEAD TO
MORE FREEZING DRIZZLE PROCESSES. NOT EXPECTING A WIDESPREAD IMPACT
THOUGH LOCALIZED ICY PATCHES COULD OCCUR ON ROADWAYS AND WALKWAYS.
SKY CONDITIONS WILL REMAIN CLOUDY TODAY AND WILL HOLD TEMPERATURES
IN THE 20S TO LOWER 30S ONCE AGAIN.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

WE HAVE MUCH TO DISCUSS.

THIS WEEKEND WILL BE CHARACTERIZED BY GENERAL STRATUS AND
HAZE/FOG WITHIN A BROAD WARM AIR/MOISTURE ADVECTION REGIME IN
LIGHT SOUTHERLY SURFACE FLOW. THIS WILL ALSO LEAD TO A SLOW
WARMING TREND...WITH HIGH TEMPERATURES IN THE MID 30S TO LOWER 40S
BY SUNDAY. DURING THE NIGHTTIME AND EARLY MORNING HOURS...BOTH
FROM FRIDAY NIGHT INTO SATURDAY AND FROM SATURDAY NIGHT INTO
SUNDAY...THERE WILL BE INCREASING CHANCES FOR FOG AND DRIZZLE AS
THE NEAR SURFACE CLOUD LAYER GRADUALLY SATURATES AND DEEPENS. ON
FRIDAY NIGHT THE LAYER DEPTHS ARE STILL MARGINAL FOR DRIZZLE AND
THERE IS NO DISCERNIBLE SOURCE OF LIFT TO GENERATE THIS LIGHT
PRECIPITATION. HOWEVER...EVEN EARLY THIS MORNING /FRIDAY/ AND THE
PREVIOUS NIGHT WE HAVE SEEN PATCHY FREEZING DRIZZLE AROUND THE
AREA AND THE SATURATION...WHILE SHALLOW...SEEMS EVEN BETTER ON
FRIDAY NIGHT. GIVEN THE PERSISTENCE OF THE PATTERN...HAVE OPTED TO
INCLUDE DRIZZLE ACROSS THE AREA BETWEEN ABOUT MIDNIGHT AND
SUNRISE. TEMPERATURES WILL BE BELOW FREEZING DURING THIS PERIOD SO
ANY DRIZZLE THAT DOES FORM MAY CAUSE TRAVEL
IMPACTS...HOWEVER...CONFIDENCE IN OCCURRENCE IS EASILY TOO LOW TO
WARRANT ANY HEADLINE CONSIDERATION AT THIS TIME. ON SATURDAY NIGHT
A STRONG SURGE OF THETA E ADVECTION WILL MOVE ACROSS THE
AREA...MAINLY AFTER MIDNIGHT...WITH AN ATTENDANT INCREASE IN THE
DEPTH OF THE WARM CLOUD LAYER. THIS LEADS TO A CONSIDERABLY HIGHER
CONFIDENCE IN DRIZZLE OCCURRENCE LATE SATURDAY NIGHT INTO SUNDAY.
HOWEVER...BY THEN TEMPERATURES WILL BE NEAR OR ABOVE FREEZING IN
MANY AREAS SO IT IS DIFFICULT TO DIFFERENTIATE WHERE THE DRIZZLE
WILL FREEZE AND WHERE IT IS NOT...WITH THE BEST CHANCES FOR
FREEZING DRIZZLE ACROSS THE NORTHERN HALF OR SO OF THE FORECAST
AREA. COMPLICATING THIS FURTHER...FORECAST SOUNDINGS AND
CONCEPTUAL MODELS SUGGEST THAT THE ADVECTION SURGE THAT WILL
TRIGGER DRIZZLE GENERATION MAY PUSH TEMPERATURES FROM BELOW
FREEZING TO ABOVE FREEZING AND IT IS DIFFICULT TO TELL HOW QUICKLY
THIS WILL BE REFLECTED IN SURFACE/ROAD TEMPERATURES. IN ANY
EVENT...THOSE TRAVELING THIS WEEKEND SHOULD KEEP AN EYE ON THE
FORECAST FOR UPDATES ON THE POTENTIAL FOR FREEZING DRIZZLE DURING
THE NIGHTTIME/MORNING HOURS THIS WEEKEND.

BY SUNDAY NIGHT OUR MUCH ANTICIPATED LARGER STORM SYSTEM WILL BE
APPROACHING IN THE FORM OF A 500 MB SHORTWAVE AND ASSOCIATED
SURFACE LOW PRESSURE CENTER MOVING QUICKLY SOUTHEAST ACROSS THE
DAKOTAS. AS THIS SYSTEM REACHES IOWA WE WILL SEE PRECIPITATION
BREAK OUT ACROSS THE STATE FROM WEST TO EAST...MAINLY AFTER
MIDNIGHT SUNDAY NIGHT AND INTO MONDAY. TEMPERATURES WILL BE ABOVE
FREEZING LEADING TO RAIN ACROSS MOST OF THE AREA...WITH THE
EXCEPTION BEING IN OUR FAR NORTH WHERE TEMPERATURES NEAR FREEZING
MAY LEAD TO A WINTRY MIX OF PRECIPITATION BUT WITH LITTLE TO NO
SNOW OR ICE ACCUMULATION THROUGH MONDAY. THE STACKED LOW PRESSURE
CENTER SHOULD BE LOCATED OVER NORTHERN IOWA/SOUTHERN MINNESOTA BY
MONDAY NIGHT...THEREAFTER OCCLUDING AND MOVING SLOWLY TO THE EAST.
THIS WILL LEAD TO A RAIN TO SNOW TRANSITION FROM WEST TO EAST ON
MONDAY NIGHT...FOLLOWED BY A DAY OR TWO OF LIGHT SNOW WITHIN THE
LARGE CLOUD AND PRECIP SHIELD ON THE BACKSIDE OF THE SYSTEM. WHILE
CHANCES FOR SNOWFLAKES ARE HIGH ACROSS MUCH OF THE AREA FROM
MONDAY NIGHT THROUGH TUESDAY...GIVEN THAT THE LOW WILL BE SLOWLY
FILLING AND MOVING AWAY THE QPF IS FAIRLY LOW AND ANY SNOWFALL
AMOUNTS WILL PROBABLY BE LIGHT. THIS MAY STILL PRODUCE SOME TRAVEL
IMPACTS BUT THESE ARE VERY DIFFICULT TO DIAGNOSE AT THIS RANGE. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM IN THE COMING DAYS.

THE LIGHT SNOW TRAILING THE EARLY WEEK SYSTEM SHOULD CLEAR OUT OF
THE AREA ROUGHLY AROUND TUESDAY NIGHT OR POSSIBLY WEDNESDAY. IT
DOES APPEAR THAT ANOTHER STORM SYSTEM WILL APPROACH OUR AREA FROM
THE WEST LATE NEXT WEEK...JUST BEYOND THE CURRENT SEVEN DAY
FORECAST...WITH SOME CHANCE FOR PRECIPITATION POSSIBLY IN THE FORM
OF ADDITIONAL SNOWFALL.

&&

.AVIATION...19/06Z
ISSUED AT 1141 PM CST THU DEC 18 2014

LOW STRATUS WILL CONTINUE TO BE WIDESPREAD FOR THE DURATION OF THE
FORECAST. VFR CONDITIONS WILL PERSIST ACRS THE FAR NORTHEAST
THROUGH MUCH OF THE NIGHT BUT THE SLOW NORTH AND EAST PROGRESSION
OF MVFR TO IFR CEILINGS WILL CONTINUE AS SOUTHERLY FLOW BEGINS TO
INCREASE AS SURFACE RIDGE SLIDES SLOWLY EASTWARD. THE MVFR TO IFR
CONDITIONS WILL PERSIST INTO FRIDAY AND FRIDAY EVENING AS THE
MOIST LOW LEVEL FLOW CONTINUES. GFS IS INDICATING SOME -DZ/-FZDZ
BY AFTERNOON ACROSS PORTIONS OF THE FORECAST AREA AS FORCING
INCREASES. HAVE NOT INCLUDED AT THIS TIME BUT WILL HAVE TO BE
MONITORED FOR INCLUSION IN SUBSEQUENT FORECASTS. SURFACE WINDS
WILL BE LIGHT OVERNIGHT BECOMING SOUTHEAST TO SOUTH ON FRIDAY BUT
REMAINING LIGHT.


&&

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

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...COGIL





000
FXUS63 KDMX 190929
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
329 AM CST FRI DEC 19 2014

.SHORT TERM /TODAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

LOW LEVEL MOISTURE SURGE IS LIFTING NORTHEAST ACROSS CENTRAL IOWA
THIS MORNING. WEAK FORCING WITHIN THIS SATURATED LAYER HAS PRODUCED
A MIX OF LIGHT FREEZING DRIZZLE OR FLURRIES WITH SATURATION TOPS
CURRENTLY BETWEEN -7C AND -9C WHICH IS ON THE EDGE BETWEEN GOOD ICE
INTRODUCTION AND SUPER COOLED DROPLETS. THE SATURATION DEPTHS
DECREASE FROM THE TOP OF THE LAYER THROUGH THE MORNING AND THUS
SHOULD DECREASE THE AMOUNT OF ICE INTRODUCTION WHICH WOULD LEAD TO
MORE FREEZING DRIZZLE PROCESSES. NOT EXPECTING A WIDESPREAD IMPACT
THOUGH LOCALIZED ICY PATCHES COULD OCCUR ON ROADWAYS AND WALKWAYS.
SKY CONDITIONS WILL REMAIN CLOUDY TODAY AND WILL HOLD TEMPERATURES
IN THE 20S TO LOWER 30S ONCE AGAIN.

.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 329 AM CST FRI DEC 19 2014

WE HAVE MUCH TO DISCUSS.

THIS WEEKEND WILL BE CHARACTERIZED BY GENERAL STRATUS AND
HAZE/FOG WITHIN A BROAD WARM AIR/MOISTURE ADVECTION REGIME IN
LIGHT SOUTHERLY SURFACE FLOW. THIS WILL ALSO LEAD TO A SLOW
WARMING TREND...WITH HIGH TEMPERATURES IN THE MID 30S TO LOWER 40S
BY SUNDAY. DURING THE NIGHTTIME AND EARLY MORNING HOURS...BOTH
FROM FRIDAY NIGHT INTO SATURDAY AND FROM SATURDAY NIGHT INTO
SUNDAY...THERE WILL BE INCREASING CHANCES FOR FOG AND DRIZZLE AS
THE NEAR SURFACE CLOUD LAYER GRADUALLY SATURATES AND DEEPENS. ON
FRIDAY NIGHT THE LAYER DEPTHS ARE STILL MARGINAL FOR DRIZZLE AND
THERE IS NO DISCERNIBLE SOURCE OF LIFT TO GENERATE THIS LIGHT
PRECIPITATION. HOWEVER...EVEN EARLY THIS MORNING /FRIDAY/ AND THE
PREVIOUS NIGHT WE HAVE SEEN PATCHY FREEZING DRIZZLE AROUND THE
AREA AND THE SATURATION...WHILE SHALLOW...SEEMS EVEN BETTER ON
FRIDAY NIGHT. GIVEN THE PERSISTENCE OF THE PATTERN...HAVE OPTED TO
INCLUDE DRIZZLE ACROSS THE AREA BETWEEN ABOUT MIDNIGHT AND
SUNRISE. TEMPERATURES WILL BE BELOW FREEZING DURING THIS PERIOD SO
ANY DRIZZLE THAT DOES FORM MAY CAUSE TRAVEL
IMPACTS...HOWEVER...CONFIDENCE IN OCCURRENCE IS EASILY TOO LOW TO
WARRANT ANY HEADLINE CONSIDERATION AT THIS TIME. ON SATURDAY NIGHT
A STRONG SURGE OF THETA E ADVECTION WILL MOVE ACROSS THE
AREA...MAINLY AFTER MIDNIGHT...WITH AN ATTENDANT INCREASE IN THE
DEPTH OF THE WARM CLOUD LAYER. THIS LEADS TO A CONSIDERABLY HIGHER
CONFIDENCE IN DRIZZLE OCCURRENCE LATE SATURDAY NIGHT INTO SUNDAY.
HOWEVER...BY THEN TEMPERATURES WILL BE NEAR OR ABOVE FREEZING IN
MANY AREAS SO IT IS DIFFICULT TO DIFFERENTIATE WHERE THE DRIZZLE
WILL FREEZE AND WHERE IT IS NOT...WITH THE BEST CHANCES FOR
FREEZING DRIZZLE ACROSS THE NORTHERN HALF OR SO OF THE FORECAST
AREA. COMPLICATING THIS FURTHER...FORECAST SOUNDINGS AND
CONCEPTUAL MODELS SUGGEST THAT THE ADVECTION SURGE THAT WILL
TRIGGER DRIZZLE GENERATION MAY PUSH TEMPERATURES FROM BELOW
FREEZING TO ABOVE FREEZING AND IT IS DIFFICULT TO TELL HOW QUICKLY
THIS WILL BE REFLECTED IN SURFACE/ROAD TEMPERATURES. IN ANY
EVENT...THOSE TRAVELING THIS WEEKEND SHOULD KEEP AN EYE ON THE
FORECAST FOR UPDATES ON THE POTENTIAL FOR FREEZING DRIZZLE DURING
THE NIGHTTIME/MORNING HOURS THIS WEEKEND.

BY SUNDAY NIGHT OUR MUCH ANTICIPATED LARGER STORM SYSTEM WILL BE
APPROACHING IN THE FORM OF A 500 MB SHORTWAVE AND ASSOCIATED
SURFACE LOW PRESSURE CENTER MOVING QUICKLY SOUTHEAST ACROSS THE
DAKOTAS. AS THIS SYSTEM REACHES IOWA WE WILL SEE PRECIPITATION
BREAK OUT ACROSS THE STATE FROM WEST TO EAST...MAINLY AFTER
MIDNIGHT SUNDAY NIGHT AND INTO MONDAY. TEMPERATURES WILL BE ABOVE
FREEZING LEADING TO RAIN ACROSS MOST OF THE AREA...WITH THE
EXCEPTION BEING IN OUR FAR NORTH WHERE TEMPERATURES NEAR FREEZING
MAY LEAD TO A WINTRY MIX OF PRECIPITATION BUT WITH LITTLE TO NO
SNOW OR ICE ACCUMULATION THROUGH MONDAY. THE STACKED LOW PRESSURE
CENTER SHOULD BE LOCATED OVER NORTHERN IOWA/SOUTHERN MINNESOTA BY
MONDAY NIGHT...THEREAFTER OCCLUDING AND MOVING SLOWLY TO THE EAST.
THIS WILL LEAD TO A RAIN TO SNOW TRANSITION FROM WEST TO EAST ON
MONDAY NIGHT...FOLLOWED BY A DAY OR TWO OF LIGHT SNOW WITHIN THE
LARGE CLOUD AND PRECIP SHIELD ON THE BACKSIDE OF THE SYSTEM. WHILE
CHANCES FOR SNOWFLAKES ARE HIGH ACROSS MUCH OF THE AREA FROM
MONDAY NIGHT THROUGH TUESDAY...GIVEN THAT THE LOW WILL BE SLOWLY
FILLING AND MOVING AWAY THE QPF IS FAIRLY LOW AND ANY SNOWFALL
AMOUNTS WILL PROBABLY BE LIGHT. THIS MAY STILL PRODUCE SOME TRAVEL
IMPACTS BUT THESE ARE VERY DIFFICULT TO DIAGNOSE AT THIS RANGE. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM IN THE COMING DAYS.

THE LIGHT SNOW TRAILING THE EARLY WEEK SYSTEM SHOULD CLEAR OUT OF
THE AREA ROUGHLY AROUND TUESDAY NIGHT OR POSSIBLY WEDNESDAY. IT
DOES APPEAR THAT ANOTHER STORM SYSTEM WILL APPROACH OUR AREA FROM
THE WEST LATE NEXT WEEK...JUST BEYOND THE CURRENT SEVEN DAY
FORECAST...WITH SOME CHANCE FOR PRECIPITATION POSSIBLY IN THE FORM
OF ADDITIONAL SNOWFALL.

&&

.AVIATION...19/06Z
ISSUED AT 1141 PM CST THU DEC 18 2014

LOW STRATUS WILL CONTINUE TO BE WIDESPREAD FOR THE DURATION OF THE
FORECAST. VFR CONDITIONS WILL PERSIST ACRS THE FAR NORTHEAST
THROUGH MUCH OF THE NIGHT BUT THE SLOW NORTH AND EAST PROGRESSION
OF MVFR TO IFR CEILINGS WILL CONTINUE AS SOUTHERLY FLOW BEGINS TO
INCREASE AS SURFACE RIDGE SLIDES SLOWLY EASTWARD. THE MVFR TO IFR
CONDITIONS WILL PERSIST INTO FRIDAY AND FRIDAY EVENING AS THE
MOIST LOW LEVEL FLOW CONTINUES. GFS IS INDICATING SOME -DZ/-FZDZ
BY AFTERNOON ACROSS PORTIONS OF THE FORECAST AREA AS FORCING
INCREASES. HAVE NOT INCLUDED AT THIS TIME BUT WILL HAVE TO BE
MONITORED FOR INCLUSION IN SUBSEQUENT FORECASTS. SURFACE WINDS
WILL BE LIGHT OVERNIGHT BECOMING SOUTHEAST TO SOUTH ON FRIDAY BUT
REMAINING LIGHT.


&&

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

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...COGIL




000
FXUS63 KDMX 190548
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1148 PM CST THU DEC 18 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014

SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.

THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.

.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014

THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE.  FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW.  THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER.  TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.

SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW.  SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA.  AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH.  THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.

SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY.  HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA.  THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA.  THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS.  THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY.  SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING.  PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH.  DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT.  IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.

THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY.  ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.

&&

.AVIATION...19/06Z
ISSUED AT 1141 PM CST THU DEC 18 2014

LOW STRATUS WILL CONTINUE TO BE WIDESPREAD FOR THE DURATION OF THE
FORECAST. VFR CONDITIONS WILL PERSIST ACRS THE FAR NORTHEAST
THROUGH MUCH OF THE NIGHT BUT THE SLOW NORTH AND EAST PROGRESSION
OF MVFR TO IFR CEILINGS WILL CONTINUE AS SOUTHERLY FLOW BEGINS TO
INCREASE AS SURFACE RIDGE SLIDES SLOWLY EASTWARD. THE MVFR TO IFR
CONDITIONS WILL PERSIST INTO FRIDAY AND FRIDAY EVENING AS THE
MOIST LOW LEVEL FLOW CONTINUES. GFS IS INDICATING SOME -DZ/-FZDZ
BY AFTERNOON ACROSS PORTIONS OF THE FORECAST AREA AS FORCING
INCREASES. HAVE NOT INCLUDED AT THIS TIME BUT WILL HAVE TO BE
MONITORED FOR INCLUSION IN SUBSEQUENT FORECASTS. SURFACE WINDS
WILL BE LIGHT OVERNIGHT BECOMING SOUTHEAST TO SOUTH ON FRIDAY BUT
REMAINING LIGHT.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...COGIL




000
FXUS63 KDMX 190548
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1148 PM CST THU DEC 18 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014

SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.

THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.

.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014

THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE.  FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW.  THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER.  TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.

SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW.  SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA.  AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH.  THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.

SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY.  HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA.  THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA.  THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS.  THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY.  SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING.  PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH.  DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT.  IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.

THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY.  ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.

&&

.AVIATION...19/06Z
ISSUED AT 1141 PM CST THU DEC 18 2014

LOW STRATUS WILL CONTINUE TO BE WIDESPREAD FOR THE DURATION OF THE
FORECAST. VFR CONDITIONS WILL PERSIST ACRS THE FAR NORTHEAST
THROUGH MUCH OF THE NIGHT BUT THE SLOW NORTH AND EAST PROGRESSION
OF MVFR TO IFR CEILINGS WILL CONTINUE AS SOUTHERLY FLOW BEGINS TO
INCREASE AS SURFACE RIDGE SLIDES SLOWLY EASTWARD. THE MVFR TO IFR
CONDITIONS WILL PERSIST INTO FRIDAY AND FRIDAY EVENING AS THE
MOIST LOW LEVEL FLOW CONTINUES. GFS IS INDICATING SOME -DZ/-FZDZ
BY AFTERNOON ACROSS PORTIONS OF THE FORECAST AREA AS FORCING
INCREASES. HAVE NOT INCLUDED AT THIS TIME BUT WILL HAVE TO BE
MONITORED FOR INCLUSION IN SUBSEQUENT FORECASTS. SURFACE WINDS
WILL BE LIGHT OVERNIGHT BECOMING SOUTHEAST TO SOUTH ON FRIDAY BUT
REMAINING LIGHT.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...COGIL





000
FXUS63 KDMX 182329
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
529 PM CST THU DEC 18 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014

SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.

THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.

.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014

THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE.  FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW.  THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER.  TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.

SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW.  SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA.  AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH.  THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.

SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY.  HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA.  THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA.  THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS.  THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY.  SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING.  PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH.  DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT.  IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.

THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY.  ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.

&&

.AVIATION...19/00Z
ISSUED AT 529 PM CST THU DEC 18 2014

WIDESPREAD CLOUDINESS IS EXPECTED FOR THE DURATION OF THE FORECAST
WITH LOW MVFR TO IFR STRATUS BECOMING COMMON PLACE LATE TONIGHT
INTO FRIDAY. IN EFFECT...WILL SEE LOW LEVEL WARM ADVECTION VERY
GRADUALLY INCREASE WITH WEAK MOISTURE TRANSPORT ACROSS IOWA
HELPING TO KEEP STATUS PERSISTENT. SURFACE WIND FLOW WILL BE WEAK
AND GRADUALLY BECOME SOUTHEAST TO SOUTH ON FRIDAY. VISIBILITIES
MAY ALSO SEE SOME RESTRICTIONS IN LIGHT FOG LATE TONIGHT.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...COGIL





000
FXUS63 KDMX 182132
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
332 PM CST THU DEC 18 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014

SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.

THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.

.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014

THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE.  FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW.  THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER.  TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.

SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW.  SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA.  AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH.  THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.

SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY.  HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA.  THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA.  THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS.  THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY.  SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING.  PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH.  DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT.  IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.

THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY.  ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.

&&

.AVIATION...18/18Z
ISSUED AT 1141 AM CST THU DEC 18 2014

SNOW IS WINDING DOWN ACROSS SOUTHERN IOWA THIS AFTERNOON WITH IFR
TO LOW MVFR CEILINGS LINGERING OVER THE AREA. IFR/LOW MVFR STRATUS
IS ALSO HANGING ON ACROSS PORTIONS OF NE IOWA. EXPECT LITTLE
IMPROVEMENT THROUGHOUT THE DAY WITH A LARGE SHIELD OF MVFR TO IFR
STRATUS OVER NEBRASKA AND WESTERN IOWA ADVECTING OVER CENTRAL IOWA
TONIGHT AND LINGERING THROUGH THE END OF THE TAF PERIOD.


&&

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

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...SKOW





000
FXUS63 KDMX 182132
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
332 PM CST THU DEC 18 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 324 PM CST THU DEC 18 2014

SNOW HAS ENDED OVER THE SOUTHEASTERN CWA AS THE CULPRIT UPPER LEVEL
WAVE HAS RAPIDLY WEAKENED AND DGZ FORCING HAS WANED. BASED ON WEBCAM
IMAGES AND A FEW SPOTTER/COOP REPORTS...MOST AREAS IN THE SOUTHERN
THREE TIERS OF COUNTIES SAW LESS THAN AN INCH OF SNOW. ATTENTION NOW
TURNS UPSTREAM TO A LARGE STRATUS PLUME STRETCHING FROM NORTHWEST
MONTANA TO THE TEXAS PANHANDLE...WITH THE EASTERN FRONT NOW JUST
ABOUT TO ENTER THE WESTERN CWA. LIGHT WEST TO SOUTHWEST FLOW IN THE
LOWEST 1 KM OF THE ATMOSPHERE BEHIND A DEPARTING SURFACE RIDGE
SHOULD ADVECT THIS CLOUD MASS OVER CENTRAL IOWA TONIGHT AND KEEP
SKIES OVERCAST ALL NIGHT AND INTO TOMORROW MORNING. THE CLOUDS
SHOULD ALSO BOLSTER LOW TEMPS TONIGHT COMPARED TO PREVIOUS NIGHTS
AND DIDN`T DEVIATE MUCH FROM GUIDANCE IN THIS RESPECT.

THE BIGGEST UNCERTAINTY FOR TONIGHT IS THE POSSIBILITY OF FLURRIES
OR FREEZING DRIZZLE WEST OF I-35. SHORT-RANGE MODEL SOUNDINGS (RUC
AND HRRR IN PARTICULAR) SATURATE THE LOWEST 5 KFT OF THE ATMOSPHERE
IN THIS REGION TONIGHT WITH NEARLY ISOTHERMAL PROFILES IN THIS LAYER
HOVERING BETWEEN -4 AND -7C. WITH THIS CONDITIONAL ICE PROBABILITY
...WENT WITH A MIX OF OCCASIONAL FLURRIES AND PATCHY FZDZ. FORCING
SHOULD BE MARGINAL AT BEST AND NO ACCUMULATION OF SNOW OR ICE IS
ANTICIPATED. ANY LIFT WITH AN UPPER LEVEL TROUGH ON WATER VAPOR
IMAGERY NW OF THE CWA SHOULD STAY NORTH AND EAST OF THE AREA.
ISENTROPIC UPGLIDE IN THE LOWEST 100MB OF THE ATMOSPHERE IS
PRESENT...BUT AGAIN VERY WEAK.

.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 324 PM CST THU DEC 18 2014

THE WEATHER IN THE LONG TERM WILL IN GENERAL BE MORE ACTIVE THEN
WHAT WE HAVE SEEN IN A WHILE.  FRIDAY THROUGH SUNDAY THERE WILL BE
NUMEROUS RELATIVELY WEAK SHORT WAVES MOVE ACROSS IOWA IN A GENERALLY
ZONAL FLOW.  THROUGH SATURDAY MOISTURE WILL EITHER BE SPARSE OR
SHALLOW SO I AM NOT EXPECTING MUCH WITH THESE SHORTWAVES IN TERMS OF
SENSIBLE WEATHER EXCEPT FOR CLOUD COVER.  TEMPS SHOULD BE RATHER
MILD FOR MID TO LATE DECEMBER.

SATURDAY NIGHT THROUGH SUNDAY A LITTLE STRONGER SHORT WAVE MOVES IN
AND MOISTURE DEPTH INCREASES SLIGHTLY ALTHOUGH IT IS STILL VERY
SHALLOW.  SOUNDINGS DO NOT INDICATE ICE INTRODUCTION AND WHILE THERE
ARE MODEL DIFFERENCES AS TO WHERE ANY WEAK FORCING MIGHT OCCUR...IT
DOES APPEAR THAT THE NORTHERN HALF OF IOWA IS MORE LIKELY TO SEE
THIS THAN SOUTHERN IOWA.  AS A RESULT I KEPT THE MENTION OF FREEZING
DRIZZLE CONFINED TO THE NORTH.  THE SOUNDING DOES SATURATE
OR BEGIN TO SATURATE SUFFICIENTLY LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING THROUGH THE DENDRITIC ZONE THAT WE COULD TRANSITION
TO SOME LIGHT SNOW UP NORTH...ESPECIALLY SUNDAY MORNING. THAT
SHORTWAVE EXITS DURING THE EARLY AFTERNOON AND TEMPS WARM
SUFFICIENTLY FOR A WINTERY MIX CHANGING TO RAIN ACROSS AT LEAST
SOME OF THE AREA.

SUNDAY NIGHT THROUGH MONDAY A MORE POTENT SHORTWAVE MOVES INTO
IOWA...AFFECTING THE WEST SUNDAY NIGHT AND THE REST OF THE AREA
THROUGH TUESDAY.  HERE MODELS DIVERGE ON HOW TO HANDLE THIS SYSTEM.
THE GFS KEEP THE UPPER LEVEL WAVE OPEN AND DEVELOPS A CLOSED SURFACE
LOW OVER CENTRAL TO NORTHEAST IOWA.  THE EURO DRASTICALLY DEPEND
THE UPPER WAVE TO OUR WEST THEN CONTINUES TO DEVELOP IT INTO A
CLOSED LOW MONDAY NIGHT AND TUESDAY ACROSS EASTERN IOWA.  THE
RESULTANT CLOSED SURFACE LOW IS OVER EASTERN IOWA AS WELL AND
FURTHER SOUTHWEST THAN THE GFS HAS.  THE GFS REALLY DEVELOPS THE QG
FORCING ACROSS CENTRAL IOWA SUNDAY NIGHT THEN IS SIGNIFICANTLY
WEAKER THROUGH TUESDAY.  SOUNDINGS SHOW A PROFILE THAT IS PRETTY
WARM THROUGH MONDAY AFTERNOON WHEN THE PROFILE COOLS TO BELOW
FREEZING.  PRECIP THROUGH EARLY MONDAY AFTERNOON SHOULD BE RAIN WITH
AN OCCASIONAL WINTERY MIX ESPECIALLY UP NORTH.  DURING THE AFTERNOON
WE WILL BE TRANSITIONING TO A RAIN/SNOW MIX BEFORE GOING TO ALL SNOW
MONDAY NIGHT.  IT IS TOO FAR OUT TO CONSIDER SNOWFALL AMOUNTS YET
AND GIVEN THE MODEL DISCREPANCIES IT WOULD BE HARD TO DO AT THIS
POINT.

THAT SYSTEM PULLS OUT BY CHRISTMAS EVE LEAVING US WITH SEASONAL
TEMPS AND MAINLY DRY.  ANOTHER SYSTEM PUSHES IN FOR THURSDAY NIGHT
AND FRIDAY AND GIVEN THE STRENGTH OF THE TROUGH OVER US THAT FAR OUT
WE WILL GET SOME PRECIP OUT OF THE SYSTEM BUT MODEL DISCREPANCIES
ARE TOO BIG TO GIVE MUCH IN THE WAY OF TIMING AND AMOUNT DETAILS.

&&

.AVIATION...18/18Z
ISSUED AT 1141 AM CST THU DEC 18 2014

SNOW IS WINDING DOWN ACROSS SOUTHERN IOWA THIS AFTERNOON WITH IFR
TO LOW MVFR CEILINGS LINGERING OVER THE AREA. IFR/LOW MVFR STRATUS
IS ALSO HANGING ON ACROSS PORTIONS OF NE IOWA. EXPECT LITTLE
IMPROVEMENT THROUGHOUT THE DAY WITH A LARGE SHIELD OF MVFR TO IFR
STRATUS OVER NEBRASKA AND WESTERN IOWA ADVECTING OVER CENTRAL IOWA
TONIGHT AND LINGERING THROUGH THE END OF THE TAF PERIOD.


&&

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

$$

SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...SKOW




000
FXUS63 KDMX 181745
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1145 AM CST THU DEC 18 2014

.UPDATE...
ISSUED AT 920 AM CST THU DEC 18 2014

BASED ON INCOMING COOP SNOWFALL REPORTS AND RADAR TRENDS...HAVE
LOWERED SNOWFALL AMOUNTS BY SEVERAL TENTHS OF AN INCH AND REMOVED
SNOW NORTH OF I-80 FOR THE REST OF TODAY. DRY LAYER VERY PROMINENT
ON THE 12Z 0AX SOUNDING IS RESULTING IN A SHARP CUTOFF IN THE
PRECIP BAND JUST SOUTH OF DSM. IT IS QUITE POSSIBLE THAT THE
METRO MAY SEE ONLY FLURRIES BY THE TIME THIS EVENT IS ALL SAID
AND DONE WITH THE BEST DGZ FORCING ALREADY SHIFTING TOWARDS SE
IOWA AND RADAR ECHOS DECREASING OVER THE SW CWA.

&&

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/18Z
ISSUED AT 1141 AM CST THU DEC 18 2014

SNOW IS WINDING DOWN ACROSS SOUTHERN IOWA THIS AFTERNOON WITH IFR
TO LOW MVFR CEILINGS LINGERING OVER THE AREA. IFR/LOW MVFR STRATUS
IS ALSO HANGING ON ACROSS PORTIONS OF NE IOWA. EXPECT LITTLE
IMPROVEMENT THROUGHOUT THE DAY WITH A LARGE SHIELD OF MVFR TO IFR
STRATUS OVER NEBRASKA AND WESTERN IOWA ADVECTING OVER CENTRAL IOWA
TONIGHT AND LINGERING THROUGH THE END OF THE TAF PERIOD.

&&

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

$$

UPDATE...SKOW
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...SKOW





000
FXUS63 KDMX 181745
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1145 AM CST THU DEC 18 2014

.UPDATE...
ISSUED AT 920 AM CST THU DEC 18 2014

BASED ON INCOMING COOP SNOWFALL REPORTS AND RADAR TRENDS...HAVE
LOWERED SNOWFALL AMOUNTS BY SEVERAL TENTHS OF AN INCH AND REMOVED
SNOW NORTH OF I-80 FOR THE REST OF TODAY. DRY LAYER VERY PROMINENT
ON THE 12Z 0AX SOUNDING IS RESULTING IN A SHARP CUTOFF IN THE
PRECIP BAND JUST SOUTH OF DSM. IT IS QUITE POSSIBLE THAT THE
METRO MAY SEE ONLY FLURRIES BY THE TIME THIS EVENT IS ALL SAID
AND DONE WITH THE BEST DGZ FORCING ALREADY SHIFTING TOWARDS SE
IOWA AND RADAR ECHOS DECREASING OVER THE SW CWA.

&&

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/18Z
ISSUED AT 1141 AM CST THU DEC 18 2014

SNOW IS WINDING DOWN ACROSS SOUTHERN IOWA THIS AFTERNOON WITH IFR
TO LOW MVFR CEILINGS LINGERING OVER THE AREA. IFR/LOW MVFR STRATUS
IS ALSO HANGING ON ACROSS PORTIONS OF NE IOWA. EXPECT LITTLE
IMPROVEMENT THROUGHOUT THE DAY WITH A LARGE SHIELD OF MVFR TO IFR
STRATUS OVER NEBRASKA AND WESTERN IOWA ADVECTING OVER CENTRAL IOWA
TONIGHT AND LINGERING THROUGH THE END OF THE TAF PERIOD.

&&

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

$$

UPDATE...SKOW
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...SKOW




000
FXUS63 KDMX 181523
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
923 AM CST THU DEC 18 2014

.UPDATE...
ISSUED AT 920 AM CST THU DEC 18 2014

BASED ON INCOMING COOP SNOWFALL REPORTS AND RADAR TRENDS...HAVE
LOWERED SNOWFALL AMOUNTS BY SEVERAL TENTHS OF AN INCH AND REMOVED
SNOW NORTH OF I-80 FOR THE REST OF TODAY. DRY LAYER VERY PROMINENT
ON THE 12Z 0AX SOUNDING IS RESULTING IN A SHARP CUTOFF IN THE
PRECIP BAND JUST SOUTH OF DSM. IT IS QUITE POSSIBLE THAT THE
METRO MAY SEE ONLY FLURRIES BY THE TIME THIS EVENT IS ALL SAID
AND DONE WITH THE BEST DGZ FORCING ALREADY SHIFTING TOWARDS SE
IOWA AND RADAR ECHOS DECREASING OVER THE SW CWA.

&&

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/12Z
ISSUED AT 555 AM CST THU DEC 18 2014

BAND OF SNOW MOVING INTO SOUTHERN IOWA WILL DROP VISIBILITIES TO
MVFR AT TIMES AT KOTM/KDSM THIS MORNING BEFORE DIMINISHING. CIGS
WILL DROP TO MVFR AS WELL IN THAT AREA. PRIMARILY VFR CONDITIONS
AT OTHER SITES THROUGH MUCH OF THE DAY. CIGS ARE EXPECTED TO LOWER
LATE TODAY AND THROUGH TONIGHT WITH WIDESPREAD MVFR OVERNIGHT.
LIGHT WINDS ARE EXPECTED THROUGH THE PERIOD.


&&

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

$$

UPDATE...SKOW
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DONAVON





000
FXUS63 KDMX 181523
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
923 AM CST THU DEC 18 2014

.UPDATE...
ISSUED AT 920 AM CST THU DEC 18 2014

BASED ON INCOMING COOP SNOWFALL REPORTS AND RADAR TRENDS...HAVE
LOWERED SNOWFALL AMOUNTS BY SEVERAL TENTHS OF AN INCH AND REMOVED
SNOW NORTH OF I-80 FOR THE REST OF TODAY. DRY LAYER VERY PROMINENT
ON THE 12Z 0AX SOUNDING IS RESULTING IN A SHARP CUTOFF IN THE
PRECIP BAND JUST SOUTH OF DSM. IT IS QUITE POSSIBLE THAT THE
METRO MAY SEE ONLY FLURRIES BY THE TIME THIS EVENT IS ALL SAID
AND DONE WITH THE BEST DGZ FORCING ALREADY SHIFTING TOWARDS SE
IOWA AND RADAR ECHOS DECREASING OVER THE SW CWA.

&&

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/12Z
ISSUED AT 555 AM CST THU DEC 18 2014

BAND OF SNOW MOVING INTO SOUTHERN IOWA WILL DROP VISIBILITIES TO
MVFR AT TIMES AT KOTM/KDSM THIS MORNING BEFORE DIMINISHING. CIGS
WILL DROP TO MVFR AS WELL IN THAT AREA. PRIMARILY VFR CONDITIONS
AT OTHER SITES THROUGH MUCH OF THE DAY. CIGS ARE EXPECTED TO LOWER
LATE TODAY AND THROUGH TONIGHT WITH WIDESPREAD MVFR OVERNIGHT.
LIGHT WINDS ARE EXPECTED THROUGH THE PERIOD.


&&

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

$$

UPDATE...SKOW
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DONAVON




000
FXUS63 KDMX 181155
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
555 AM CST THU DEC 18 2014

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/12Z
ISSUED AT 555 AM CST THU DEC 18 2014

BAND OF SNOW MOVING INTO SOUTHERN IOWA WILL DROP VISIBILITIES TO
MVFR AT TIMES AT KOTM/KDSM THIS MORNING BEFORE DIMINISHING. CIGS
WILL DROP TO MVFR AS WELL IN THAT AREA. PRIMARILY VFR CONDITIONS
AT OTHER SITES THROUGH MUCH OF THE DAY. CIGS ARE EXPECTED TO LOWER
LATE TODAY AND THROUGH TONIGHT WITH WIDESPREAD MVFR OVERNIGHT.
LIGHT WINDS ARE EXPECTED THROUGH THE PERIOD.

&&

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

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DONAVON




000
FXUS63 KDMX 181155
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
555 AM CST THU DEC 18 2014

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/12Z
ISSUED AT 555 AM CST THU DEC 18 2014

BAND OF SNOW MOVING INTO SOUTHERN IOWA WILL DROP VISIBILITIES TO
MVFR AT TIMES AT KOTM/KDSM THIS MORNING BEFORE DIMINISHING. CIGS
WILL DROP TO MVFR AS WELL IN THAT AREA. PRIMARILY VFR CONDITIONS
AT OTHER SITES THROUGH MUCH OF THE DAY. CIGS ARE EXPECTED TO LOWER
LATE TODAY AND THROUGH TONIGHT WITH WIDESPREAD MVFR OVERNIGHT.
LIGHT WINDS ARE EXPECTED THROUGH THE PERIOD.

&&

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

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DONAVON





000
FXUS63 KDMX 180936
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
336 AM CST THU DEC 18 2014

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/06Z
ISSUED AT 1140 PM CST WED DEC 17 2014

SYSTEM ACROSS PLAINS WILL CONTINUE TO LIFT NORTHEAST THROUGH
THURSDAY. CLOUDS WILL MOVE INTO IOWA WITH PRIMARILY MID AND HIGH
CLOUDINESS OVERNIGHT AND VFR CONDITIONS. AS DEEPER SATURATION
APPROACHES FROM THE SOUTH TOWARD DAYBREAK...MVFR TO IFR CONDITIONS
NEAR THE MISSOURI BORDER ARE EXPECTED ALTHOUGH DRIER LOW LEVEL AIR
WILL KEEP LOCATIONS FARTHER NORTH VFR. THERE WILL BE SOME LOW
LEVEL CLOUDS NEAR KMCW OVERNIGHT NEAR RIDGE AXIS AND THIS MAY
LINGER INTO THURSDAY MORNING AS FLOW REMAINS QUITE LIGHT. WITH
PASSAGE OF SYSTEM ON THURSDAY...THREAT OF PRECIPITATION IN THE
SOUTH WILL END AFTER MIDDAY. HOWEVER...LOW TO MID LEVEL MOISTURE
WILL REMAIN WITH WIDESPREAD STATUS EXPECTED TO PERSIST THROUGH THE
END OF THE FORECAST.


&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...COGIL





000
FXUS63 KDMX 180936
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
336 AM CST THU DEC 18 2014

.SHORT TERM /TODAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

AN UPPER LEVEL SHORT WAVE IS MOVING ACROSS MISSOURI THIS MORNING
WITH THE NORTHERN FRINGE OF KINEMATIC FORCING REACHING INTO SOUTHERN
IOWA. A BRANCH OF THE WARM CONVEYOR BELT IS WRAPPING AROUND THE
NORTH SIDE WITH MOISTURE OVERRUNNING THE SURFACE COLDER AIR. THE
COMBINATION OF MOISTURE AND FORCING HAS RESULTED IN A BAND OF SNOW
LIFTING NORTHEAST THROUGH NORTHEAST KANSAS AND NORTHERN MISSOURI.
THIS BAND OF SNOW WILL MOVE INTO SOUTHERN IOWA EARLY THIS MORNING
HOWEVER ITS NORTHEAST EXTENT WILL BE LIMITED BY DRY AIR ASSOCIATED
WITH A RIDGE OF HIGH PRESSURE SITUATED OVER NORTHEAST IOWA. IN
ADDITION...FORCING WILL WEAKEN AS THE UPPER LEVEL SYSTEM DEPARTS TO
THE EAST AND LEAVES THE SNOW BAND BEHIND TO DIMINISH. SNOWFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE OVER THE SOUTHERN 2 TIERS OF
COUNTIES WITH MINOR ACCUMULATIONS OF A FEW TENTHS POSSIBLE AS FAR
NORTH AS INTERSTATE 80. POTENTIAL FOR FREEZING DRIZZLE BY THIS
AFTERNOON IS LOW. MOISTURE DEPTHS WITH RELATIVE HUMIDITIES GREATER
THAN 75 PERCENT REMAIN RELATIVELY HIGH AND COLD FOR ICE TO REMAIN
INTRODUCED AND RESULTING IN LIGHT SNOW OR FLURRIES COMPARED TO
FZDZ.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 336 AM CST THU DEC 18 2014

OUR WEATHER PATTERN IS SET TO BECOME MORE ACTIVE OVER THE COMING
DAYS. INITIALLY A SERIES OF 500 MB TROUGHS WILL CROSS THE
REGION...THE FIRST AROUND FRIDAY NIGHT AND ANOTHER AROUND
SATURDAY NIGHT/SUNDAY...GRADUALLY CARVING OUT BROAD CYCLONIC FLOW
ACROSS THE CENTRAL U.S. CONCURRENT WITH A LARGE 500 MB HIGH
PRESSURE DOME DEVELOPING OVER THE EASTERN PACIFIC. WITH THE FIRST
TROUGH PASSAGE OVER IOWA ON FRIDAY NIGHT THERE IS A POTENTIAL FOR
SOME STRATUS AND DRIZZLE...BUT FORECAST SOUNDINGS INDICATE THAT
LOW LEVEL MOISTURE AND LIFT WILL PROBABLY BE INSUFFICIENT TO
GENERATE PRECIPITATION. WITH THE SECOND TROUGH ON SATURDAY NIGHT
INTO SUNDAY THERE IS A BETTER SIGNAL FOR SOME LIGHT
PRECIPITATION...PROBABLY IN THE FORM OF DRIZZLE OR FREEZING
DRIZZLE. IT IS LIKELY THAT TEMPERATURES WILL FALL BELOW FREEZING
SATURDAY NIGHT...HOWEVER...DEWPOINTS AND TEMPERATURES MAY RECOVER
TO JUST ABOVE FREEZING BEFORE DRIZZLE DEVELOPS.
NEVERTHELESS...GIVEN THE POSSIBILITY OF FREEZING DRIZZLE AND ITS
ASSOCIATED IMPACTS HAVE ADDED A CHANCE INTO THE OUTGOING FORECAST
PACKAGE. WE WILL BE CLOSELY MONITORING THIS POSSIBILITY OVER THE
NEXT COUPLE OF DAYS.

AS MENTIONED EARLIER...BY THE LATTER PART OF THE WEEKEND A BROAD
500 MB TROUGH WILL HAVE BEEN CARVED OUT OVER THE CENTRAL U.S. A
COMPACT BUT ENERGETIC SHORTWAVE WILL THEN OVERTOP THE EASTERN
PACIFIC RIDGE AND ROCKET SOUTHEASTWARD OVER THE NORTHERN ROCKIES
ON SUNDAY...SUBSEQUENTLY DIGGING AND CLOSING OFF AS A LOW OVER
MINNESOTA AND IOWA BY MONDAY NIGHT. THIS LOW WILL THEN WOBBLE OVER
THE REGION...OR SLIGHTLY TO THE EAST OVER WISCONSIN AND LAKE
MICHIGAN...BEFORE FINALLY EJECTING EASTWARD AROUND CHRISTMAS EVE.
IN TERMS OF SENSIBLE WEATHER...THE INITIAL APPROACH OF THE LOW ON
WILL SPREAD A SWATH OF WARM ADVECTION REGIME PRECIPITATION ACROSS
IOWA ON SUNDAY NIGHT INTO MONDAY...THEN AS THE LOW MOVES NEARBY OR
OVERHEAD A LARGE STRATUS AND PRECIPITATION SHIELD WILL AFFECT MOST
OF THE REGION AND EVENTUALLY CHANGE OVER TO SNOW. THERE IS STILL
SOME UNCERTAINTY AS TO THE LOCATION OF THE LOW PRESSURE CENTER AND
ATTENDANT TEMPERATURE FIELDS...BUT IT SEEMS LIKELY THAT INITIALLY
THE PRECIPITATION WILL BE MOSTLY IN THE FORM OF RAIN WITH A WINTRY
MIX ACROSS NORTHERN IOWA...THEN BECOME LIGHTER BY THE TIME A
CHANGE TO SNOW OCCURS LATER IN THE EVENT. THIS WILL LIMIT SNOW
ACCUMULATIONS ACROSS MOST OF IOWA...BUT IN THE NORTH THERE COULD
BE SOME DECENT AMOUNTS DEPENDING ON HOW THE TEMPERATURES SET UP.
CERTAINLY TOO EARLY FOR ANY HEADLINE DIAGNOSIS BUT CERTAINLY ALL
EYES WILL BE ON THIS LARGE STORM SYSTEM IN THE COMING DAYS.

&&

.AVIATION...18/06Z
ISSUED AT 1140 PM CST WED DEC 17 2014

SYSTEM ACROSS PLAINS WILL CONTINUE TO LIFT NORTHEAST THROUGH
THURSDAY. CLOUDS WILL MOVE INTO IOWA WITH PRIMARILY MID AND HIGH
CLOUDINESS OVERNIGHT AND VFR CONDITIONS. AS DEEPER SATURATION
APPROACHES FROM THE SOUTH TOWARD DAYBREAK...MVFR TO IFR CONDITIONS
NEAR THE MISSOURI BORDER ARE EXPECTED ALTHOUGH DRIER LOW LEVEL AIR
WILL KEEP LOCATIONS FARTHER NORTH VFR. THERE WILL BE SOME LOW
LEVEL CLOUDS NEAR KMCW OVERNIGHT NEAR RIDGE AXIS AND THIS MAY
LINGER INTO THURSDAY MORNING AS FLOW REMAINS QUITE LIGHT. WITH
PASSAGE OF SYSTEM ON THURSDAY...THREAT OF PRECIPITATION IN THE
SOUTH WILL END AFTER MIDDAY. HOWEVER...LOW TO MID LEVEL MOISTURE
WILL REMAIN WITH WIDESPREAD STATUS EXPECTED TO PERSIST THROUGH THE
END OF THE FORECAST.


&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...COGIL




000
FXUS63 KDMX 180541
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1141 PM CST WED DEC 17 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014

A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.

THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014

A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.

&&

.AVIATION...18/06Z
ISSUED AT 1140 PM CST WED DEC 17 2014

SYSTEM ACROSS PLAINS WILL CONTINUE TO LIFT NORTHEAST THROUGH
THURSDAY. CLOUDS WILL MOVE INTO IOWA WITH PRIMARILY MID AND HIGH
CLOUDINESS OVERNIGHT AND VFR CONDITIONS. AS DEEPER SATURATION
APPROACHES FROM THE SOUTH TOWARD DAYBREAK...MVFR TO IFR CONDITIONS
NEAR THE MISSOURI BORDER ARE EXPECTED ALTHOUGH DRIER LOW LEVEL AIR
WILL KEEP LOCATIONS FARTHER NORTH VFR. THERE WILL BE SOME LOW
LEVEL CLOUDS NEAR KMCW OVERNIGHT NEAR RIDGE AXIS AND THIS MAY
LINGER INTO THURSDAY MORNING AS FLOW REMAINS QUITE LIGHT. WITH
PASSAGE OF SYSTEM ON THURSDAY...THREAT OF PRECIPITATION IN THE
SOUTH WILL END AFTER MIDDAY. HOWEVER...LOW TO MID LEVEL MOISTURE
WILL REMAIN WITH WIDESPREAD STATUS EXPECTED TO PERSIST THROUGH THE
END OF THE FORECAST.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...REV
AVIATION...COGIL




000
FXUS63 KDMX 180541
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1141 PM CST WED DEC 17 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014

A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.

THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014

A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.

&&

.AVIATION...18/06Z
ISSUED AT 1140 PM CST WED DEC 17 2014

SYSTEM ACROSS PLAINS WILL CONTINUE TO LIFT NORTHEAST THROUGH
THURSDAY. CLOUDS WILL MOVE INTO IOWA WITH PRIMARILY MID AND HIGH
CLOUDINESS OVERNIGHT AND VFR CONDITIONS. AS DEEPER SATURATION
APPROACHES FROM THE SOUTH TOWARD DAYBREAK...MVFR TO IFR CONDITIONS
NEAR THE MISSOURI BORDER ARE EXPECTED ALTHOUGH DRIER LOW LEVEL AIR
WILL KEEP LOCATIONS FARTHER NORTH VFR. THERE WILL BE SOME LOW
LEVEL CLOUDS NEAR KMCW OVERNIGHT NEAR RIDGE AXIS AND THIS MAY
LINGER INTO THURSDAY MORNING AS FLOW REMAINS QUITE LIGHT. WITH
PASSAGE OF SYSTEM ON THURSDAY...THREAT OF PRECIPITATION IN THE
SOUTH WILL END AFTER MIDDAY. HOWEVER...LOW TO MID LEVEL MOISTURE
WILL REMAIN WITH WIDESPREAD STATUS EXPECTED TO PERSIST THROUGH THE
END OF THE FORECAST.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...REV
AVIATION...COGIL





000
FXUS63 KDMX 172335
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
535 PM CST WED DEC 17 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014

A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.

THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014

A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.

&&

.AVIATION...18/00Z
ISSUED AT 520 PM CST WED DEC 17 2014

SYSTEM IN PLAINS WILL CONTINUE TO LIFT NORTHEAST AND WEAKEN
TONIGHT INTO THURSDAY. INITIALLY...VFR CEILINGS WILL SPREAD ACROSS
IOWA TONIGHT BUT WITH DRY LOW LEVELS...CLOUDS WILL REMAIN MID TO
HIGH LEVEL. DEEPER SATURATION OCCURS NEAR THE MISSOURI BORDER AND
SOME MVFR CEILINGS WITH LIGHT SNOW WILL BE POSSIBLE NEAR THE
MISSOURI BORDER BY DAYBREAK ON THURSDAY. HOWEVER...MUCH OF THE
FORECAST AREA WILL REMAIN WITH VFR CONDITIONS THROUGH THURSDAY
WITH THE POSSIBLE EXCEPTION OF KOTM. SURFACE WINDS WILL REMAIN
GENERALLY LIGHT AND VARIABLE FOR THE DURATION OF THE FORECAST.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...REV
AVIATION...COGIL




000
FXUS63 KDMX 172335
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
535 PM CST WED DEC 17 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014

A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.

THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014

A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.

&&

.AVIATION...18/00Z
ISSUED AT 520 PM CST WED DEC 17 2014

SYSTEM IN PLAINS WILL CONTINUE TO LIFT NORTHEAST AND WEAKEN
TONIGHT INTO THURSDAY. INITIALLY...VFR CEILINGS WILL SPREAD ACROSS
IOWA TONIGHT BUT WITH DRY LOW LEVELS...CLOUDS WILL REMAIN MID TO
HIGH LEVEL. DEEPER SATURATION OCCURS NEAR THE MISSOURI BORDER AND
SOME MVFR CEILINGS WITH LIGHT SNOW WILL BE POSSIBLE NEAR THE
MISSOURI BORDER BY DAYBREAK ON THURSDAY. HOWEVER...MUCH OF THE
FORECAST AREA WILL REMAIN WITH VFR CONDITIONS THROUGH THURSDAY
WITH THE POSSIBLE EXCEPTION OF KOTM. SURFACE WINDS WILL REMAIN
GENERALLY LIGHT AND VARIABLE FOR THE DURATION OF THE FORECAST.

&&

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

&&

$$

SHORT TERM...SKOW
LONG TERM...REV
AVIATION...COGIL





000
FXUS63 KDMX 172106
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
306 PM CST WED DEC 17 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014

A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.

THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014

A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.

&&

.AVIATION...17/18Z
ISSUED AT 1145 AM CST WED DEC 17 2014

VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT...THOUGH PATCHES OF
MVFR STRATUS ARE POSSIBLE AROUND MCW AND ALO THIS AFTERNOON BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO MENTION IN THE TAFS. LOWER CIGS
AND SNOW MOVE INTO SOUTHERN IOWA AFTER 06Z...THOUGH HOW FAR NORTH
THE SNOW PROGRESSES WILL BE A CHALLENGE FOR THE DSM/FOD TAFS.
BEST CHANCE OF MVFR CIGS/VSBYS WILL BE AT OTM FROM 12Z TO THE END
OF THE TAF PERIOD.

&&

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

$$

SHORT TERM...SKOW
LONG TERM...REV
AVIATION...SKOW





000
FXUS63 KDMX 172106
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
306 PM CST WED DEC 17 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 245 PM CST WED DEC 17 2014

A QUIET AFTERNOON IS IN STORE FOR THE CWA WITH SURFACE HIGH PRESSURE
ANCHORED ALONG THE MISSOURI RIVER VALLEY. A SHARP 300 MB SHORTWAVE
TROUGH CURRENTLY EJECTING FROM THE FOUR CORNERS REGION WILL ENTER
SOUTHWEST IOWA BY 12Z THURSDAY. NAM/GFS ARE TOO SLOW WITH RETURNING
MID-LEVEL MOISTURE (MANIFESTING ITSELF AS AN ALTOSTRATUS DECK) NOW
WELL INTO SW IOWA AS WELL AS WITH PRECIP COVERAGE WITH THIS SYSTEM
IN OKLAHOMA. THE HRRR BEST REFLECTS REALITY IN TERMS OF PRECIP
COVERAGE BUT IS ABOUT 3 HOURS BEHIND THE CURVE WITH CLOUD PLACEMENT.
HAVE SUBSEQUENTLY MANUALLY INCREASED CLOUD COVER OVER THE SW HALF OF
THE CWA AND USED THE HRRR FOR TIMING THE ONSET OF SNOW IN THE
SOUTHWESTERN CWA. LOW TEMPERATURES TONIGHT...ESPECIALLY OVER THE
NORTH...WILL BE DEPENDENT ON HOW QUICKLY CLOUDS CAN ADVECT OVERHEAD.
THESE WILL NEED TO BE MONITORED THIS EVENING AND ADJUSTED UPWARD
SHOULD THE CLOUDS ADVANCE FASTER THAN CURRENTLY FORECAST.

THE FASTER MOISTURE RETURN THROWS JUST ANOTHER WRENCH IN TIMING AND
AMOUNTS OF SNOWFALL IN SOUTHERN IOWA LATE TONIGHT. 12/18Z MODEL BUFR
SOUNDINGS DEPICT A STOUT 925-850MB DRY WEDGE ATTENDANT WITH THE
SURFACE RIDGE...BUT THIS MIDLEVEL MOISTURE MAY SATURATE THE COLUMN
FASTER THAN PROGGED AND LEAD TO HIGHER SNOWFALL TOTALS. OVERALL MADE
LITTLE CHANGES TO THE FORECAST IN THIS RESPECT...BUT DID TIGHTEN THE
POP GRADIENT AS IT ADVANCES NORTHEAST FROM 09 TO 12Z THINKING THAT
THE LOW LEVEL DRY AIR WILL RESULT IN A SHARP CUTOFF IN ACCUMULATING
SNOW.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM CST WED DEC 17 2014

A FEW CHALLENGES OVER THE EXTENDED PERIOD...WITH A NUMBER OF WEAK
SYSTEMS TO AFFECT PORTIONS OF THE AREA THROUGH THE PERIOD. SPLIT
FLOW CONTINUES TO BE THE MAIN DRIVING FORCE BEHIND THE RATHER
QUIESCENT WEATHER FOR MID DECEMBER. RATHER HIGH AMPLITUDE RIDGE OF
HIGH PRESSURE STILL ANCHORED FROM THE NORTHERN PLAINS TO THE GULF
COAST NEXT FEW DAYS. FIRST WAVE CURRENTLY OVER THE SOUTHERN
PLAINS TODAY AND SHOULD MOVE NORTHEAST THROUGH THU MORNING. AHEAD
OF THE WEAK SYSTEM WARM AIR ADVECTION AND LIMITED MOISTURE WILL BE
FORCED UPWARD IN AN AREA OF ISENTROPIC LIFT OVER SOUTHERN IOWA
THURSDAY. THE LIFT AND MOISTURE WILL BE ATTEMPTING TO OVERCOME THE
DRY AIRMASS CURRENTLY IN PLACE...LIMITING OVERALL AMOUNTS. THIS
WILL RESULT IN SOME RATHER LIGHT SNOW DURING THE MORNING HOURS
WITH MINOR ACCUMULATIONS GENERALLY LESS THAN AN INCH. DURING THE
EARLY AFTERNOON HOURS...BUFR SOUNDINGS SHOW THAT WE LOSE ICE
INTRODUCTION ACROSS THE SOUTHWEST AND SOUTH. HAVE INTRODUCED SOME
PATCHY FREEZING DRIZZLE ALONG WITH VERY LIGHT SNOW DURING THE
AFTERNOON HOURS...THOUGH EXPECTATIONS ARE THAT ANY PRECIPITATION
BY THAT TIME WILL BE VERY LIGHT AND LITTLE IF ANY ICE ACCUMULATION
IS EXPECTED. NEXT SYSTEM ARRIVES BY SUNDAY AND MONDAY AND EXTENDS
INTO TUESDAY. LOWER CONFIDENCE MOVING FORWARD WITH A CONSENSUS
SOLUTION AS THE GFS IS QUITE MILD WHILE THE EURO IS NOW SUGGESTING
A SOLUTION WITH MORE SIGNIFICANT DYNAMIC COOLING AS THE PRECIP
ARRIVES INTO MONDAY. THE EURO SUGGESTS MORE SNOW THAN RAIN/SNOW
MIX. GIVEN THE EVENT IS STILL 5 DAYS AWAY...WILL HOLD ONTO CURRENT
MIX TRENDS FOR NOW...AND MONITOR DURING SUBSEQUENT MODEL PACKAGES.
THE ONE TREND THAT IS BEGINNING TO EMERGE IS COLDER AIR AS NEXT
WEEK PROGRESSES. AS A STRONG PACNW STREAM WAVE ADVANCES EAST INTO
THE WESTERN STATES...MIDWEST RIDGE FINALLY BEGINS TO BREAK DOWN
AND BECOME DISPLACED BY A LONG WAVE TROUGH. THIS SHOULD SPELL A
TRANSITION TO A MORE ACTIVE AND COLDER PATTERN TOWARD THE END OF
THE EXTENDED. AS THE WAVE TUESDAY DEEPENS...A RATHER STRONG SFC
WAVE WILL EJECT NORTH NORTHEAST OUT OF EASTERN TEXAS TO EASTERN
MICHIGAN WEDNESDAY. GIVEN THE CURRENT GFS/EURO PACKAGES...THE MAIN
H850 MOISTURE PLUME...BETTER FORCING...AND HIGHER PRECIPITATION
AMOUNTS WILL PROBABLY END UP EAST OF THE REGION. WILL MONITOR FOR
GENERAL WESTWARD DRIFT NEXT SEVERAL PACKAGES...THIS SOMETIMES
OCCURS WITH WINTER STORM EVOLUTION IN MODEL PACKAGES...FIRST
PROJECTING THE EVENT TOO FAR EAST THEN PULLING IT BACK AS THE
EVENT NEARS.

&&

.AVIATION...17/18Z
ISSUED AT 1145 AM CST WED DEC 17 2014

VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT...THOUGH PATCHES OF
MVFR STRATUS ARE POSSIBLE AROUND MCW AND ALO THIS AFTERNOON BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO MENTION IN THE TAFS. LOWER CIGS
AND SNOW MOVE INTO SOUTHERN IOWA AFTER 06Z...THOUGH HOW FAR NORTH
THE SNOW PROGRESSES WILL BE A CHALLENGE FOR THE DSM/FOD TAFS.
BEST CHANCE OF MVFR CIGS/VSBYS WILL BE AT OTM FROM 12Z TO THE END
OF THE TAF PERIOD.

&&

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

$$

SHORT TERM...SKOW
LONG TERM...REV
AVIATION...SKOW




000
FXUS63 KDMX 171741
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1141 AM CST WED DEC 17 2014

.UPDATE...
ISSUED AT 1145 AM CST WED DEC 17 2014

MINOR SKY ADJUSTMENTS WERE MADE FOR THE AFTERNOON FORECAST TO
REFLECT THE CLEARER CONDITIONS IN NORTHERN IOWA. STRATOCUMULUS
DECK IS TRYING TO REFORM OVER THE FAR NE CWA BUT HAS BEEN
STRUGGLING TO ADVANCE MUCH INTO BREMER AND BLACK HAWK COUNTIES.

&&

.SHORT TERM /TODAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

NO SIGNIFICANT WEATHER OF CONCERN TODAY...BUT TEMPS MAY BE A TAD
PROBLEMATIC. RIGHT ENTRANCE REGION OF IA/IL JET SEGMENT AND WEAK
FORCING DRIVEN BY WRN KS SHORT WAVE AHEAD OF SWRN CONUS TROUGH
CONTINUE TO SPREAD TOKEN MID CLOUDS AND PRECIP ALOFT INTO SWRN
IA. FORCING REMAINS OF SIMILAR MAGNITUDE THROUGHOUT THE DAY...IS
MAINLY 3KM AND ABOVE...AND CONTINUES TO ADVANCE INTO SURFACE RIDGE
SO NO PRECIP IS ANTICIPATED THROUGH VALID PERIOD.

MODELS ARE HAVING SOME DIFFICULTY HANDLING CURRENT TEMP REGIME.
TEMPS HAVE COOLED BELOW SOME MODELS WHERE SKIES HAVE CLEARED. HIGH
RES MODELS ARE DOING BETTER THAN TRADITIONAL OPERATIONAL RUNS AS
HRRR...RAP AND GEM REGIONAL MODELS BETTER RESEMBLE REALITY.
QUESTION IS WHETHER TO EXTRAPOLATE THEIR SOLUTIONS INTO THE FUTURE
AS THEY VARY QUITE A BIT. RAP AND GEM REGIONAL KEEP THINGS QUITE
COOL WITH MINIMAL REBOUND WHILE HRRR IS BACK UP TOWARD MODEL
CONSENSUS BY AFTERNOON. EVEN THOUGH WINDS WILL DIMINISH SOMEWHAT
IN THE SURFACE RIDGE...STILL EXPECT SOME MIXING WITHOUT SNOW COVER
SO HAVE ONLY GONE JUST A TOUCH BELOW MODEL CONSENSUS WHICH IS NOT
DISSIMILAR TO MOS SUGGESTIONS.

.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

A WEAK 500 MB TROUGH WILL PROGRESS ACROSS KANSAS AND MISSOURI ON
WEDNESDAY NIGHT AND THURSDAY...SPREADING LIGHT PRECIPITATION THAT
MAY MAKE IT INTO MAINLY SOUTHERN IOWA. HOWEVER...THERE WILL BE A
SURFACE HIGH PRESSURE RIDGE BUILD ACROSS THE STATE DURING THAT
TIME RESULTING IN LOW LEVEL DRY AIR ISSUES AS DEPICTED BY MOST
FORECAST SOUNDINGS. IT APPEARS PROBABLE THAT THERE WILL AT LEAST
BE SOME FLURRIES OR VERY LIGHT SNOW ACROSS OUR SOUTHERN
COUNTIES...BUT FURTHER NORTH PRECIPITATION IS MUCH LESS LIKELY AND
EVEN IN THE SOUTH ANY ACCUMULATIONS SHOULD BE LIGHT. HAVE
MAINTAINED CHANCE POPS LATE WEDNESDAY NIGHT AND THURSDAY MORNING
WITH SNOWFALL AMOUNTS AROUND AN INCH OR LESS AND GENERALLY LIMITED
TO I-80 SOUTHWARD. THERE IS A POSSIBILITY OF FREEZING DRIZZLE AT
TIMES IF THE CLOUD LAYER IS SUFFICIENTLY SHALLOW/WARM...HOWEVER AT
THIS TIME THAT IS AN UNLIKELY SCENARIO AND IT HAS NOT BEEN
INCLUDED IN THE FORECAST DUE TO THE LOW PROBABILITY OF
OCCURRENCE.

FROM THURSDAY NIGHT THROUGH SATURDAY THE AFOREMENTIONED SURFACE
HIGH PRESSURE RIDGE WILL REMAIN ANCHORED JUST TO OUR EAST...FROM
THE GREAT LAKES DOWN ACROSS ILLINOIS...RESULTING IN VERY LIGHT
SOUTHERLY FLOW AND LIKELY SEVERAL MORE DAYS OF LOW STRATUS CLOUDS
THAT WILL LIMIT TEMPERATURE FLUCTUATIONS. HAVE INCREASED CLOUD
COVER FORECAST AND COMPRESSED DIURNAL TEMPERATURE SPREADS
ACCORDINGLY. IT IS PROBABLE THAT THIS WILL MANIFEST AS MORE
DRY BUT CLOUDY AND DREARY WEATHER TO END THE WORK WEEK.

BY SATURDAY A LONGWAVE 500 MB TROUGH WILL BE CROSSING THE ROCKIES
AND SHAPING UP TO BE A BIG PLAYER IN OUR WEATHER FOR THE FIRST
HALF OF NEXT WEEK. THE TROUGH WILL REACH THE HIGH PLAINS AND THE
MIDWEST BY SUNDAY AND SUBSEQUENTLY DEEPEN AS IT IS REINFORCED BY A
SERIES OF SUCCESSIVE SHORTWAVE IMPULSES ENTERING THE TROUGH FROM
WESTERN CANADA. BY TUESDAY BOTH THE ECMWF AND GFS ARE NOW CARVING
OUT A MASSIVE 500 MB TROUGH ACROSS MOST OF THE CONUS...WITH A
CENTRAL CLOSED LOW SOMEWHERE OVER THE UPPER MIDWEST. FOR OUR
FORECAST AREA THIS SCENARIO WILL TRANSLATE INTO A PROLONGED PERIOD
OF PRECIPITATION CHANCES...BEGINNING SOMETIME AROUND SUNDAY OR
SUNDAY NIGHT AND PERSISTING AT INTERVALS AT LEAST THROUGH TUESDAY.
HOWEVER...PRECIPITATION TYPE WILL BE HEAVILY DEPENDENT ON THE
LOCATION OF THE UPPER AND SURFACE LOW PRESSURE CENTERS AND THEIR
ASSOCIATED THERMAL PROFILES. CURRENT LONG RANGE MODEL SOLUTIONS
SUPPORT A FAIRLY LONG PERIOD OF RAIN WITH SNOW MORE LIMITED TO
NORTHERN IOWA AND LATER IN THE EVENT...LIKELY RESULTING IN LOW
SNOWFALL AMOUNTS. HOWEVER...WITH THE SYSTEM STILL FOUR OR FIVE
DAYS AWAY AND NOT EVEN ENTERING THE RAOB NETWORK UNTIL AROUND
FRIDAY...THE SOLUTIONS ARE HARDLY STABLE AND A WIDE RANGE OF
EVENTUAL OUTCOMES IS POSSIBLE SO THE FORECAST WILL LIKELY BE
FLUCTUATING IN THE COMING DAYS. ALL INTERESTS WITH TRAVEL PLANS
AROUND CHRISTMAS SHOULD CONTINUE TO MONITOR THESE TRENDS AND HOPE
THAT TEMPERATURES STAY WARM ENOUGH FOR THE PRECIPITATION TO FALL
PREDOMINANTLY AS RAIN.

&&

.AVIATION...17/18Z
ISSUED AT 1145 AM CST WED DEC 17 2014

VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT...THOUGH PATCHES OF
MVFR STRATUS ARE POSSIBLE AROUND MCW AND ALO THIS AFTERNOON BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO MENTION IN THE TAFS. LOWER CIGS
AND SNOW MOVE INTO SOUTHERN IOWA AFTER 06Z...THOUGH HOW FAR NORTH
THE SNOW PROGRESSES WILL BE A CHALLENGE FOR THE DSM/FOD TAFS.
BEST CHANCE OF MVFR CIGS/VSBYS WILL BE AT OTM FROM 12Z TO THE END
OF THE TAF PERIOD.

&&

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

$$

UPDATE...SKOW
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...SKOW





000
FXUS63 KDMX 171741
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1141 AM CST WED DEC 17 2014

.UPDATE...
ISSUED AT 1145 AM CST WED DEC 17 2014

MINOR SKY ADJUSTMENTS WERE MADE FOR THE AFTERNOON FORECAST TO
REFLECT THE CLEARER CONDITIONS IN NORTHERN IOWA. STRATOCUMULUS
DECK IS TRYING TO REFORM OVER THE FAR NE CWA BUT HAS BEEN
STRUGGLING TO ADVANCE MUCH INTO BREMER AND BLACK HAWK COUNTIES.

&&

.SHORT TERM /TODAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

NO SIGNIFICANT WEATHER OF CONCERN TODAY...BUT TEMPS MAY BE A TAD
PROBLEMATIC. RIGHT ENTRANCE REGION OF IA/IL JET SEGMENT AND WEAK
FORCING DRIVEN BY WRN KS SHORT WAVE AHEAD OF SWRN CONUS TROUGH
CONTINUE TO SPREAD TOKEN MID CLOUDS AND PRECIP ALOFT INTO SWRN
IA. FORCING REMAINS OF SIMILAR MAGNITUDE THROUGHOUT THE DAY...IS
MAINLY 3KM AND ABOVE...AND CONTINUES TO ADVANCE INTO SURFACE RIDGE
SO NO PRECIP IS ANTICIPATED THROUGH VALID PERIOD.

MODELS ARE HAVING SOME DIFFICULTY HANDLING CURRENT TEMP REGIME.
TEMPS HAVE COOLED BELOW SOME MODELS WHERE SKIES HAVE CLEARED. HIGH
RES MODELS ARE DOING BETTER THAN TRADITIONAL OPERATIONAL RUNS AS
HRRR...RAP AND GEM REGIONAL MODELS BETTER RESEMBLE REALITY.
QUESTION IS WHETHER TO EXTRAPOLATE THEIR SOLUTIONS INTO THE FUTURE
AS THEY VARY QUITE A BIT. RAP AND GEM REGIONAL KEEP THINGS QUITE
COOL WITH MINIMAL REBOUND WHILE HRRR IS BACK UP TOWARD MODEL
CONSENSUS BY AFTERNOON. EVEN THOUGH WINDS WILL DIMINISH SOMEWHAT
IN THE SURFACE RIDGE...STILL EXPECT SOME MIXING WITHOUT SNOW COVER
SO HAVE ONLY GONE JUST A TOUCH BELOW MODEL CONSENSUS WHICH IS NOT
DISSIMILAR TO MOS SUGGESTIONS.

.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

A WEAK 500 MB TROUGH WILL PROGRESS ACROSS KANSAS AND MISSOURI ON
WEDNESDAY NIGHT AND THURSDAY...SPREADING LIGHT PRECIPITATION THAT
MAY MAKE IT INTO MAINLY SOUTHERN IOWA. HOWEVER...THERE WILL BE A
SURFACE HIGH PRESSURE RIDGE BUILD ACROSS THE STATE DURING THAT
TIME RESULTING IN LOW LEVEL DRY AIR ISSUES AS DEPICTED BY MOST
FORECAST SOUNDINGS. IT APPEARS PROBABLE THAT THERE WILL AT LEAST
BE SOME FLURRIES OR VERY LIGHT SNOW ACROSS OUR SOUTHERN
COUNTIES...BUT FURTHER NORTH PRECIPITATION IS MUCH LESS LIKELY AND
EVEN IN THE SOUTH ANY ACCUMULATIONS SHOULD BE LIGHT. HAVE
MAINTAINED CHANCE POPS LATE WEDNESDAY NIGHT AND THURSDAY MORNING
WITH SNOWFALL AMOUNTS AROUND AN INCH OR LESS AND GENERALLY LIMITED
TO I-80 SOUTHWARD. THERE IS A POSSIBILITY OF FREEZING DRIZZLE AT
TIMES IF THE CLOUD LAYER IS SUFFICIENTLY SHALLOW/WARM...HOWEVER AT
THIS TIME THAT IS AN UNLIKELY SCENARIO AND IT HAS NOT BEEN
INCLUDED IN THE FORECAST DUE TO THE LOW PROBABILITY OF
OCCURRENCE.

FROM THURSDAY NIGHT THROUGH SATURDAY THE AFOREMENTIONED SURFACE
HIGH PRESSURE RIDGE WILL REMAIN ANCHORED JUST TO OUR EAST...FROM
THE GREAT LAKES DOWN ACROSS ILLINOIS...RESULTING IN VERY LIGHT
SOUTHERLY FLOW AND LIKELY SEVERAL MORE DAYS OF LOW STRATUS CLOUDS
THAT WILL LIMIT TEMPERATURE FLUCTUATIONS. HAVE INCREASED CLOUD
COVER FORECAST AND COMPRESSED DIURNAL TEMPERATURE SPREADS
ACCORDINGLY. IT IS PROBABLE THAT THIS WILL MANIFEST AS MORE
DRY BUT CLOUDY AND DREARY WEATHER TO END THE WORK WEEK.

BY SATURDAY A LONGWAVE 500 MB TROUGH WILL BE CROSSING THE ROCKIES
AND SHAPING UP TO BE A BIG PLAYER IN OUR WEATHER FOR THE FIRST
HALF OF NEXT WEEK. THE TROUGH WILL REACH THE HIGH PLAINS AND THE
MIDWEST BY SUNDAY AND SUBSEQUENTLY DEEPEN AS IT IS REINFORCED BY A
SERIES OF SUCCESSIVE SHORTWAVE IMPULSES ENTERING THE TROUGH FROM
WESTERN CANADA. BY TUESDAY BOTH THE ECMWF AND GFS ARE NOW CARVING
OUT A MASSIVE 500 MB TROUGH ACROSS MOST OF THE CONUS...WITH A
CENTRAL CLOSED LOW SOMEWHERE OVER THE UPPER MIDWEST. FOR OUR
FORECAST AREA THIS SCENARIO WILL TRANSLATE INTO A PROLONGED PERIOD
OF PRECIPITATION CHANCES...BEGINNING SOMETIME AROUND SUNDAY OR
SUNDAY NIGHT AND PERSISTING AT INTERVALS AT LEAST THROUGH TUESDAY.
HOWEVER...PRECIPITATION TYPE WILL BE HEAVILY DEPENDENT ON THE
LOCATION OF THE UPPER AND SURFACE LOW PRESSURE CENTERS AND THEIR
ASSOCIATED THERMAL PROFILES. CURRENT LONG RANGE MODEL SOLUTIONS
SUPPORT A FAIRLY LONG PERIOD OF RAIN WITH SNOW MORE LIMITED TO
NORTHERN IOWA AND LATER IN THE EVENT...LIKELY RESULTING IN LOW
SNOWFALL AMOUNTS. HOWEVER...WITH THE SYSTEM STILL FOUR OR FIVE
DAYS AWAY AND NOT EVEN ENTERING THE RAOB NETWORK UNTIL AROUND
FRIDAY...THE SOLUTIONS ARE HARDLY STABLE AND A WIDE RANGE OF
EVENTUAL OUTCOMES IS POSSIBLE SO THE FORECAST WILL LIKELY BE
FLUCTUATING IN THE COMING DAYS. ALL INTERESTS WITH TRAVEL PLANS
AROUND CHRISTMAS SHOULD CONTINUE TO MONITOR THESE TRENDS AND HOPE
THAT TEMPERATURES STAY WARM ENOUGH FOR THE PRECIPITATION TO FALL
PREDOMINANTLY AS RAIN.

&&

.AVIATION...17/18Z
ISSUED AT 1145 AM CST WED DEC 17 2014

VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT...THOUGH PATCHES OF
MVFR STRATUS ARE POSSIBLE AROUND MCW AND ALO THIS AFTERNOON BUT
CONFIDENCE WAS NOT HIGH ENOUGH TO MENTION IN THE TAFS. LOWER CIGS
AND SNOW MOVE INTO SOUTHERN IOWA AFTER 06Z...THOUGH HOW FAR NORTH
THE SNOW PROGRESSES WILL BE A CHALLENGE FOR THE DSM/FOD TAFS.
BEST CHANCE OF MVFR CIGS/VSBYS WILL BE AT OTM FROM 12Z TO THE END
OF THE TAF PERIOD.

&&

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

$$

UPDATE...SKOW
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...SKOW




000
FXUS63 KDMX 171203
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
603 AM CST WED DEC 17 2014

.SHORT TERM /TODAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

NO SIGNIFICANT WEATHER OF CONCERN TODAY...BUT TEMPS MAY BE A TAD
PROBLEMATIC. RIGHT ENTRANCE REGION OF IA/IL JET SEGMENT AND WEAK
FORCING DRIVEN BY WRN KS SHORT WAVE AHEAD OF SWRN CONUS TROUGH
CONTINUE TO SPREAD TOKEN MID CLOUDS AND PRECIP ALOFT INTO SWRN
IA. FORCING REMAINS OF SIMILAR MAGNITUDE THROUGHOUT THE DAY...IS
MAINLY 3KM AND ABOVE...AND CONTINUES TO ADVANCE INTO SURFACE RIDGE
SO NO PRECIP IS ANTICIPATED THROUGH VALID PERIOD.

MODELS ARE HAVING SOME DIFFICULTY HANDLING CURRENT TEMP REGIME.
TEMPS HAVE COOLED BELOW SOME MODELS WHERE SKIES HAVE CLEARED. HIGH
RES MODELS ARE DOING BETTER THAN TRADITIONAL OPERATIONAL RUNS AS
HRRR...RAP AND GEM REGIONAL MODELS BETTER RESEMBLE REALITY.
QUESTION IS WHETHER TO EXTRAPOLATE THEIR SOLUTIONS INTO THE FUTURE
AS THEY VARY QUITE A BIT. RAP AND GEM REGIONAL KEEP THINGS QUITE
COOL WITH MINIMAL REBOUND WHILE HRRR IS BACK UP TOWARD MODEL
CONSENSUS BY AFTERNOON. EVEN THOUGH WINDS WILL DIMINISH SOMEWHAT
IN THE SURFACE RIDGE...STILL EXPECT SOME MIXING WITHOUT SNOW COVER
SO HAVE ONLY GONE JUST A TOUCH BELOW MODEL CONSENSUS WHICH IS NOT
DISSIMILAR TO MOS SUGGESTIONS.

.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

A WEAK 500 MB TROUGH WILL PROGRESS ACROSS KANSAS AND MISSOURI ON
WEDNESDAY NIGHT AND THURSDAY...SPREADING LIGHT PRECIPITATION THAT
MAY MAKE IT INTO MAINLY SOUTHERN IOWA. HOWEVER...THERE WILL BE A
SURFACE HIGH PRESSURE RIDGE BUILD ACROSS THE STATE DURING THAT
TIME RESULTING IN LOW LEVEL DRY AIR ISSUES AS DEPICTED BY MOST
FORECAST SOUNDINGS. IT APPEARS PROBABLE THAT THERE WILL AT LEAST
BE SOME FLURRIES OR VERY LIGHT SNOW ACROSS OUR SOUTHERN
COUNTIES...BUT FURTHER NORTH PRECIPITATION IS MUCH LESS LIKELY AND
EVEN IN THE SOUTH ANY ACCUMULATIONS SHOULD BE LIGHT. HAVE
MAINTAINED CHANCE POPS LATE WEDNESDAY NIGHT AND THURSDAY MORNING
WITH SNOWFALL AMOUNTS AROUND AN INCH OR LESS AND GENERALLY LIMITED
TO I-80 SOUTHWARD. THERE IS A POSSIBILITY OF FREEZING DRIZZLE AT
TIMES IF THE CLOUD LAYER IS SUFFICIENTLY SHALLOW/WARM...HOWEVER AT
THIS TIME THAT IS AN UNLIKELY SCENARIO AND IT HAS NOT BEEN
INCLUDED IN THE FORECAST DUE TO THE LOW PROBABILITY OF
OCCURRENCE.

FROM THURSDAY NIGHT THROUGH SATURDAY THE AFOREMENTIONED SURFACE
HIGH PRESSURE RIDGE WILL REMAIN ANCHORED JUST TO OUR EAST...FROM
THE GREAT LAKES DOWN ACROSS ILLINOIS...RESULTING IN VERY LIGHT
SOUTHERLY FLOW AND LIKELY SEVERAL MORE DAYS OF LOW STRATUS CLOUDS
THAT WILL LIMIT TEMPERATURE FLUCTUATIONS. HAVE INCREASED CLOUD
COVER FORECAST AND COMPRESSED DIURNAL TEMPERATURE SPREADS
ACCORDINGLY. IT IS PROBABLE THAT THIS WILL MANIFEST AS MORE
DRY BUT CLOUDY AND DREARY WEATHER TO END THE WORK WEEK.

BY SATURDAY A LONGWAVE 500 MB TROUGH WILL BE CROSSING THE ROCKIES
AND SHAPING UP TO BE A BIG PLAYER IN OUR WEATHER FOR THE FIRST
HALF OF NEXT WEEK. THE TROUGH WILL REACH THE HIGH PLAINS AND THE
MIDWEST BY SUNDAY AND SUBSEQUENTLY DEEPEN AS IT IS REINFORCED BY A
SERIES OF SUCCESSIVE SHORTWAVE IMPULSES ENTERING THE TROUGH FROM
WESTERN CANADA. BY TUESDAY BOTH THE ECMWF AND GFS ARE NOW CARVING
OUT A MASSIVE 500 MB TROUGH ACROSS MOST OF THE CONUS...WITH A
CENTRAL CLOSED LOW SOMEWHERE OVER THE UPPER MIDWEST. FOR OUR
FORECAST AREA THIS SCENARIO WILL TRANSLATE INTO A PROLONGED PERIOD
OF PRECIPITATION CHANCES...BEGINNING SOMETIME AROUND SUNDAY OR
SUNDAY NIGHT AND PERSISTING AT INTERVALS AT LEAST THROUGH TUESDAY.
HOWEVER...PRECIPITATION TYPE WILL BE HEAVILY DEPENDENT ON THE
LOCATION OF THE UPPER AND SURFACE LOW PRESSURE CENTERS AND THEIR
ASSOCIATED THERMAL PROFILES. CURRENT LONG RANGE MODEL SOLUTIONS
SUPPORT A FAIRLY LONG PERIOD OF RAIN WITH SNOW MORE LIMITED TO
NORTHERN IOWA AND LATER IN THE EVENT...LIKELY RESULTING IN LOW
SNOWFALL AMOUNTS. HOWEVER...WITH THE SYSTEM STILL FOUR OR FIVE
DAYS AWAY AND NOT EVEN ENTERING THE RAOB NETWORK UNTIL AROUND
FRIDAY...THE SOLUTIONS ARE HARDLY STABLE AND A WIDE RANGE OF
EVENTUAL OUTCOMES IS POSSIBLE SO THE FORECAST WILL LIKELY BE
FLUCTUATING IN THE COMING DAYS. ALL INTERESTS WITH TRAVEL PLANS
AROUND CHRISTMAS SHOULD CONTINUE TO MONITOR THESE TRENDS AND HOPE
THAT TEMPERATURES STAY WARM ENOUGH FOR THE PRECIPITATION TO FALL
PREDOMINANTLY AS RAIN.

&&

.AVIATION...17/12Z
ISSUED AT 600 AM CST WED DEC 17 2014

PRIMARY CONCERN WILL BE DEPARTING STRATUS THIS MORNING. BACK EDGE
OF SUB 2KFT MVFR CIGS EXTENDS FROM KLWD-KTNU-KALO AND SHOULD EXIT
KALO MOMENTARILY AND ARE NOT INCLUDED IN THAT TAF. CIGS SHOULD
LINGER AT KOTM FOR A FEW MORE HOURS. AFTER THAT VFR CONDITIONS ARE
ANTICIPATED WITH NOTHING MORE THAN SCT-BKN MID AND HIGH CLOUDINESS
GRADUALLY INCREASING FROM THE WEST. WINDS WILL REMAIN FAIRLY
LIGHT...SLOWLY VEERING INTO THE NIGHT AND BECOMING LIGHT AND
VARIABLE EARLY THU MORNING.

&&

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

&&

$$

SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...SMALL





000
FXUS63 KDMX 171203
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
603 AM CST WED DEC 17 2014

.SHORT TERM /TODAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

NO SIGNIFICANT WEATHER OF CONCERN TODAY...BUT TEMPS MAY BE A TAD
PROBLEMATIC. RIGHT ENTRANCE REGION OF IA/IL JET SEGMENT AND WEAK
FORCING DRIVEN BY WRN KS SHORT WAVE AHEAD OF SWRN CONUS TROUGH
CONTINUE TO SPREAD TOKEN MID CLOUDS AND PRECIP ALOFT INTO SWRN
IA. FORCING REMAINS OF SIMILAR MAGNITUDE THROUGHOUT THE DAY...IS
MAINLY 3KM AND ABOVE...AND CONTINUES TO ADVANCE INTO SURFACE RIDGE
SO NO PRECIP IS ANTICIPATED THROUGH VALID PERIOD.

MODELS ARE HAVING SOME DIFFICULTY HANDLING CURRENT TEMP REGIME.
TEMPS HAVE COOLED BELOW SOME MODELS WHERE SKIES HAVE CLEARED. HIGH
RES MODELS ARE DOING BETTER THAN TRADITIONAL OPERATIONAL RUNS AS
HRRR...RAP AND GEM REGIONAL MODELS BETTER RESEMBLE REALITY.
QUESTION IS WHETHER TO EXTRAPOLATE THEIR SOLUTIONS INTO THE FUTURE
AS THEY VARY QUITE A BIT. RAP AND GEM REGIONAL KEEP THINGS QUITE
COOL WITH MINIMAL REBOUND WHILE HRRR IS BACK UP TOWARD MODEL
CONSENSUS BY AFTERNOON. EVEN THOUGH WINDS WILL DIMINISH SOMEWHAT
IN THE SURFACE RIDGE...STILL EXPECT SOME MIXING WITHOUT SNOW COVER
SO HAVE ONLY GONE JUST A TOUCH BELOW MODEL CONSENSUS WHICH IS NOT
DISSIMILAR TO MOS SUGGESTIONS.

.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 344 AM CST WED DEC 17 2014

A WEAK 500 MB TROUGH WILL PROGRESS ACROSS KANSAS AND MISSOURI ON
WEDNESDAY NIGHT AND THURSDAY...SPREADING LIGHT PRECIPITATION THAT
MAY MAKE IT INTO MAINLY SOUTHERN IOWA. HOWEVER...THERE WILL BE A
SURFACE HIGH PRESSURE RIDGE BUILD ACROSS THE STATE DURING THAT
TIME RESULTING IN LOW LEVEL DRY AIR ISSUES AS DEPICTED BY MOST
FORECAST SOUNDINGS. IT APPEARS PROBABLE THAT THERE WILL AT LEAST
BE SOME FLURRIES OR VERY LIGHT SNOW ACROSS OUR SOUTHERN
COUNTIES...BUT FURTHER NORTH PRECIPITATION IS MUCH LESS LIKELY AND
EVEN IN THE SOUTH ANY ACCUMULATIONS SHOULD BE LIGHT. HAVE
MAINTAINED CHANCE POPS LATE WEDNESDAY NIGHT AND THURSDAY MORNING
WITH SNOWFALL AMOUNTS AROUND AN INCH OR LESS AND GENERALLY LIMITED
TO I-80 SOUTHWARD. THERE IS A POSSIBILITY OF FREEZING DRIZZLE AT
TIMES IF THE CLOUD LAYER IS SUFFICIENTLY SHALLOW/WARM...HOWEVER AT
THIS TIME THAT IS AN UNLIKELY SCENARIO AND IT HAS NOT BEEN
INCLUDED IN THE FORECAST DUE TO THE LOW PROBABILITY OF
OCCURRENCE.

FROM THURSDAY NIGHT THROUGH SATURDAY THE AFOREMENTIONED SURFACE
HIGH PRESSURE RIDGE WILL REMAIN ANCHORED JUST TO OUR EAST...FROM
THE GREAT LAKES DOWN ACROSS ILLINOIS...RESULTING IN VERY LIGHT
SOUTHERLY FLOW AND LIKELY SEVERAL MORE DAYS OF LOW STRATUS CLOUDS
THAT WILL LIMIT TEMPERATURE FLUCTUATIONS. HAVE INCREASED CLOUD
COVER FORECAST AND COMPRESSED DIURNAL TEMPERATURE SPREADS
ACCORDINGLY. IT IS PROBABLE THAT THIS WILL MANIFEST AS MORE
DRY BUT CLOUDY AND DREARY WEATHER TO END THE WORK WEEK.

BY SATURDAY A LONGWAVE 500 MB TROUGH WILL BE CROSSING THE ROCKIES
AND SHAPING UP TO BE A BIG PLAYER IN OUR WEATHER FOR THE FIRST
HALF OF NEXT WEEK. THE TROUGH WILL REACH THE HIGH PLAINS AND THE
MIDWEST BY SUNDAY AND SUBSEQUENTLY DEEPEN AS IT IS REINFORCED BY A
SERIES OF SUCCESSIVE SHORTWAVE IMPULSES ENTERING THE TROUGH FROM
WESTERN CANADA. BY TUESDAY BOTH THE ECMWF AND GFS ARE NOW CARVING
OUT A MASSIVE 500 MB TROUGH ACROSS MOST OF THE CONUS...WITH A
CENTRAL CLOSED LOW SOMEWHERE OVER THE UPPER MIDWEST. FOR OUR
FORECAST AREA THIS SCENARIO WILL TRANSLATE INTO A PROLONGED PERIOD
OF PRECIPITATION CHANCES...BEGINNING SOMETIME AROUND SUNDAY OR
SUNDAY NIGHT AND PERSISTING AT INTERVALS AT LEAST THROUGH TUESDAY.
HOWEVER...PRECIPITATION TYPE WILL BE HEAVILY DEPENDENT ON THE
LOCATION OF THE UPPER AND SURFACE LOW PRESSURE CENTERS AND THEIR
ASSOCIATED THERMAL PROFILES. CURRENT LONG RANGE MODEL SOLUTIONS
SUPPORT A FAIRLY LONG PERIOD OF RAIN WITH SNOW MORE LIMITED TO
NORTHERN IOWA AND LATER IN THE EVENT...LIKELY RESULTING IN LOW
SNOWFALL AMOUNTS. HOWEVER...WITH THE SYSTEM STILL FOUR OR FIVE
DAYS AWAY AND NOT EVEN ENTERING THE RAOB NETWORK UNTIL AROUND
FRIDAY...THE SOLUTIONS ARE HARDLY STABLE AND A WIDE RANGE OF
EVENTUAL OUTCOMES IS POSSIBLE SO THE FORECAST WILL LIKELY BE
FLUCTUATING IN THE COMING DAYS. ALL INTERESTS WITH TRAVEL PLANS
AROUND CHRISTMAS SHOULD CONTINUE TO MONITOR THESE TRENDS AND HOPE
THAT TEMPERATURES STAY WARM ENOUGH FOR THE PRECIPITATION TO FALL
PREDOMINANTLY AS RAIN.

&&

.AVIATION...17/12Z
ISSUED AT 600 AM CST WED DEC 17 2014

PRIMARY CONCERN WILL BE DEPARTING STRATUS THIS MORNING. BACK EDGE
OF SUB 2KFT MVFR CIGS EXTENDS FROM KLWD-KTNU-KALO AND SHOULD EXIT
KALO MOMENTARILY AND ARE NOT INCLUDED IN THAT TAF. CIGS SHOULD
LINGER AT KOTM FOR A FEW MORE HOURS. AFTER THAT VFR CONDITIONS ARE
ANTICIPATED WITH NOTHING MORE THAN SCT-BKN MID AND HIGH CLOUDINESS
GRADUALLY INCREASING FROM THE WEST. WINDS WILL REMAIN FAIRLY
LIGHT...SLOWLY VEERING INTO THE NIGHT AND BECOMING LIGHT AND
VARIABLE EARLY THU MORNING.

&&

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

&&

$$

SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...SMALL




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