FXUS63 KDMX 160855
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
300 AM CST WED DEC 16 2009

.SHORT TERM /TODAY/...
WINDS WILL REMAIN LIGHT AND GENERALLY SOUTHERLY TODAY AS HIGH 
PRESSURE CONTINUES TO MOVE AWAY TO THE EAST AND BROAD...WEAK LOW 
PRESSURE DEVELOPS ALONG THE WESTERN HIGH PLAINS. BENEATH RIDGING 
ALOFT THIS WILL SUPPORT A STEADY WARM AIR ADVECTION REGIME RESULTING 
IN NOTICABLY HIGHER TEMPERATURES THAN YESTERDAY. NO PRECIPITATION IS 
EXPECTED DUE TO A VERY DRY ATMOSPHERIC COLUMN COMBINED WITH 
SUBSIDENCE. SOME HIGH CIRRUS CLOUDS WILL MOVE BY OVERHEAD BUT EXPECT 
MOSTLY SUNNY SKIES IN GENERAL.

.LONG TERM /TONIGHT THROUGH TUESDAY/...
A BATCH OF SHORTWAVE ENERGY MOVING ACROSS THE PAC NW TONIGHT WILL 
CROSS THE ROCKIES THEN CARVE OUT A MODEST TROUGH OVER THE UPPER 
MIDWEST BY FRIDAY. COINCIDENT WITH THIS UPPER LEVEL FEATURE...A WEAK 
SURFACE LOW WILL DEVELOP OVER THE WEST CENTRAL PLAINS EARLY THURSDAY 
AND LIKELY MOVE OVER SRN IOWA THURSDAY NIGHT BEFORE INTENSIFYING 
SOME AS IT MOVES EAST OVR IL/IN FRIDAY. THIS APPEARS TO BE A 
MOISTURE-STARVED SYSTEM GIVEN ITS TRAJECTORY AND SPEED...AND MODEL 
SOUNDINGS GENERALLY MAINTAIN A FAIRLY DRY 900-700 MB LAYER. SEEMS 
THAT THERE IS LITTLE OPPORTUNITY FOR PRECIP AS THE SYSTEM 
APPROACHES. HOWEVER...AS IT BEGINS TO INTENSIFY LATE THURSDAY NIGHT 
INTO FRIDAY MID LEVEL FRONTOGENESIS AND A DEFORMATION AXIS WILL 
LIKELY SET UP IN THE N TO NW SIDE OF THE SFC LOW. EXACTLY WHERE THIS 
ENDS UP BEING GEOGRAPHICALLY IS STILL UNCERTAIN. WILL FOLLOW A 
GFS/ECMWF BLEND AND HAVE HIGHEST POPS OVER THE SOUTHEAST 
FRIDAY...THOUGH STILL IN THE LOWER CHANCE END FOR NOW DUE TO THE 
UNCERTAINTY. DESPITE THE DRY LOWER LEVELS...SOUNDINGS ARE CLOSEST TO 
SATURATION IN THE DENDRITIC GROWTH ZONE...SO AT THE VERY 
LEAST...SOME FLURRIES SEEM PROBABLE...ESPECIALLY ACROSS THE SOUTH 
HALF THURSDAY NIGHT.

A BRIEF SURGE OF COOLER AIR WILL ENSUE SATURDAY...BUT AN ALBERTA 
CLIPPER LOW PRESSURE SYSTEM WILL QUICKLY DIVE THROUGH THE UPPER 
MIDWEST SUNDAY. ITS EVENTUAL PATH IS ALSO STILL UNCERTAIN AND HIGHLY 
DEPENDENT ON THE INTENSITY OF THE PREVIOUS WAVE OVER THE EAST COAST 
BY THAT TIME. HAVE ALSO GONE WITH A GFS/EC BLEND FOR THE FORECAST 
PATH...BUT HAVE KEPT POPS ON THE LOWER/CONSERVATIVE END FOR NOW. IF 
THE CURRENTLY PROJECTED PATH WERE TO HOLD TRUE...A QUICK COUPLE OF 
INCHES OF SNOW WILL BE STORE FOR CENTRAL IOWA SUNDAY. AS 
USUAL...BEHIND A CLIPPER SYSTEM LIKE THIS...TEMPERATURES WILL FALL 
TO WELL BELOW NORMAL LEVELS EARLY NEXT WEEK.

&&

.AVIATION...
16/06Z...VFR CONDITIONS PREVAIL DURING THE ENTIRE TAF FORECAST 
PERIOD AS HIGH PRESSURE CONTINUES TO SLOWLY SHIFT EAST THROUGH 
WEDNESDAY.  WINDS LOOK TO SLOWLY SHIFT TO THE SOUTH SOUTHWEST 
TOWARDS WEDNESDAY MORNING AND HIGH CLOUDS STILL ANTICIPATED TO 
INCREASE DURING THE AFTERNOON HOURS.  

&&

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

&&

$$

SHORT TERM...LEE
LONG TERM...MOYER
AVIATION...PODRAZIK