000
FXUS63 KDMX 161418
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
818 AM CST MON DEC 16 2013

.SHORT TERM /TODAY/...
ISSUED AT 308 AM CST MON DEC 16 2013

A LARGE STRATUS SHIELD HAS DEVELOPED OVERNIGHT ACROSS MOST OF OUR
AREA...EXCEPTING THE SOUTHWEST...ALONG WITH MUCH OF MINNESOTA AND
EASTERN IOWA. THIS IS COINCIDENT WITH THE AXIS AND WESTERN PERIPHERY
OF A LOW LEVEL RIDGE DRAPED DOWN THE MISSISSIPPI VALLEY. AS THE
RIDGE SLOWLY MOVES OFF TO THE EAST TODAY THE CLOUDS SHOULD
FOLLOW...HOWEVER THEIR EXIT PROGRESS WILL BE HAMPERED BY WEAK LOW
LEVEL FLOW AND THE LOW ANGLE OF THE DECEMBER SUN. EXPECT CLOUDY
SKIES TO PREVAIL FOR MUCH OF THE DAY OVER OUR NORTHEASTERN HALF OR
SO...NOT CLEARING OUT UNTIL MID TO LATE AFTERNOON. LIGHT SNOW IS
ALSO POSSIBLE IN OUR NORTHEAST CORNER AND HAVE MAINTAINED SLIGHT
POPS...BUT WITH LOW LEVEL DRY AIR IN PLACE DO NOT HAVE CONFIDENCE TO
GO ANY HIGHER AND IN ANY EVENT ACCUMULATIONS WOULD BE VERY LIGHT TO
NIL. TEMPERATURES ARE TRICKY ESPECIALLY GIVEN THE CLOUD COVER
ISSUE...AND HAVE MAINTAINED FORECAST HIGHS BELOW GUIDANCE ACROSS THE
NORTH AND EAST WHERE FRESH SNOW HAS FALLEN EACH OF THE LAST TWO DAYS
AND THE CLOUDS WILL LINGER LONGER...WITH HIGHS ABOVE MOS IN THE
SOUTHWEST GIVEN THE RELATIVE LACK OF SNOW AND BETTER PROBABILITY OF
SUNSHINE.

.LONG TERM /TONIGHT THROUGH SATURDAY/...
ISSUED AT 308 AM CST MON DEC 16 2013

DECENT TEMPERATURE GRADIENT WILL LIE ACROSS THE STATE UNTIL A BIG
WARM PUSH SWEEPS INTO THE STATE ON WEDNESDAY. SHORTWAVE DROPPING
SOUTHEAST TONIGHT WILL GRAZE NORTHEAST PORTIONS OF THE FORECAST
AREA WITH WEAK FORCING. THIS WILL LIKELY PRODUCE SOME
FLURRIES/VERY LIGHT SNOW NEAR MASON CITY TO WAVERLY...HOWEVER THE
BULK OF FORCING AND PCPN WILL REMAIN TO THE NORTHEAST. WILL SEE
STRONG WESTERLY SURFACE FLOW AND DRIER AIR ON TUESDAY WHICH IS
EXPECTED TO PRODUCE SOME CLEARING AND SUNSHINE DURING THE DAY.
THIS WILL HELP READINGS CLIMB TO NEAR NORMAL OR ABOVE...ESPECIALLY
IN THE SOUTHWEST HALF OF THE FORECAST AREA. RIDGE AXIS WILL SLIDE
ACROSS THE STATE TUESDAY EVENING WITH STRONG WARM ADVECTION
ENSUING INTO WEDNESDAY. 850MB TEMPS CLIMB TO +10C BY MIDDAY ACROSS
THE STATE WITH DECENT SOUTHWEST SURFACE WINDS. ANTICIPATE
TEMPERATURES INTO THE 40S...ALONG AND SOUTH OF HIGHWAY 30 AND MAY
STILL BE TOO LOW DEPENDING ON THE AMOUNT OF SUNSHINE AND MIXING.
READINGS A BIT COOLER TO THE NORTH WHERE SNOWPACK MAY LIMIT
OVERALL HEATING.

FOCUS THEN TURNS TOWARDS SURFACE LOW PROGGED TO CROSS THE STATE ON
THURSDAY. MOISTURE WILL RETURN AHEAD OF THE LOW ALTHOUGH MOST
SATURATION OCCURS IN THE LOW LEVELS WITH RELATIVELY DRIER
CONDITIONS IN THE MID TO HIGHER REACHES OF THE ATMOSPHERE. THIS
SETUP GENERALLY FAVORS DRIZZLE/VERY LIGHT RAIN IN AREAS ABOVE
FREEZING AT THE SURFACE AND THE POTENTIAL FOR FREEZING DRIZZLE
WHERE READINGS HOLD SUB FREEZING. HAVE UPDATED THE FORECAST TO
INCLUDE THE CHANCE OF FREEZING DRIZZLE/LIGHT FREEZING RAIN ACROSS
PORTIONS OF NORTHERN IOWA ON THURSDAY WHERE TEMPERATURES FAIL TO
CLIMB ABOVE FREEZING. THIS MAY INCLUDE PORTIONS OF CENTRAL IOWA
WHERE MORNING READINGS ARE NEAR FREEZING BEFORE CLIMBING BY LATE
MORNING. SYSTEM WILL PASS BY THURSDAY EVENING WITH STRONG COLD
ADVECTION BY THURSDAY NIGHT AND PCPN LIKELY BECOMING FLURRIES
BEFORE ENDING. THEREAFTER...TEMPERATURES ARE EXPECTED TO REMAIN
BELOW NORMAL INTO THE WEEKEND AS A STRONG SYSTEM PASSES TO THE
SOUTH OF THE STATE. THE SYSTEM DOES BEAR WATCHING AS THE LATEST
00Z EURO RUN WOULD INDICATE CHANCE OF SNOW ACROSS THE SOUTHEAST
HALF OF THE FORECAST AREA LATE SATURDAY INTO SUNDAY MORNING.

&&

.AVIATION...16/12Z
ISSUED AT 818 AM CST MON DEC 16 2013

WILL BE HOLDING ON TO IFR CLOUD DECK A BIT LONGER THROUGH THE MID
AFTERNOON HOURS MOST AREAS. CURRENTLY HAVE SEVERAL DECKS AND
STRATUS EXPANDING NORTHWEST TOWARD MISSOURI RIVER ATTM. UNTIL
SHORT WAVE AND BETTER MIXING APPROACHES BY MID AFTERNOON...LIKELY
THAT IMPROVEMENT WILL BE SLOW DUE TO TIME OF YEAR AND WEAK SFC
FLOW. WILL MONITOR CLOSELY FOR ANY IMPROVEMENTS PRIOR TO 18Z
PACKAGE. /REV

&&

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

$$

SHORT TERM...LEE
LONG TERM...COGIL
AVIATION...REV