FXUS63 KDMX 151733 AAB
AFDDMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1135 AM CST TUE DEC 15 2009

...UPDATED AVIATION DISCUSSION...

.SHORT TERM /TODAY/...
ANOTHER COOL AND QUIET DAY IN STORE AS HIGH PRESSURE MOVES IN FROM 
THE WEST. NORTHWEST WINDS SHOULD REMAIN FAIRLY STEADY AS EXPECTED 
SPEED INCREASE WITH DAYTIME MIXING WILL BE MITIGATED BY CLOSER 
PROXIMITY OF THE HIGH AS THE MORNING PROGRESSES. VERY COLD 
TEMPERATURES THIS MORNING STILL SUPPORT WIND CHILL VALUES OF -20 TO 
-30 ACROSS ABOUT OUR NORTHERN HALF...IN SPITE OF RELATIVELY LOW WIND 
SPEEDS...SO WIND CHILL ADVISORY WILL REMAIN UNCHANGED WITH MORNING 
ISSUANCE. MADE LITTLE CHANGE IN MAX TEMPS TODAY AS VIRTUALLY CLEAR 
SKIES WILL BE OFFSET BY LOW SOLAR ANGLE AND ENTRENCHED COLD AIR OVER 
REMAINING SNOWPACK FROM LAST WEEKS STORM.

.LONG TERM /TONIGHT THROUGH MONDAY/...
A FAIRLY NON DESCRIPT UPPER LEVEL NORTHWEST FLOW PATTERN UNTIL
LATE IN THE WEEK...WITH TEMP TRENDS REALLY THE ONLY CHALLENGE.
LOW LEVEL RIDGE AXIS PASSES EAST OF THE CWA BY MIDNIGHT
TONIGHT...WITH WARM ADVECTION ENSUING FOR THE LATTER HALF OF THE
NIGHT. THEREFORE...HAVE A NON DIURNAL TREND FOR TONIGHT...WITH
TEMPS DROPPING RAPIDLY AT SUNSET AND SLOWLY WARMING THEREAFTER.
SOUTHERLY FLOW WEDNESDAY WILL BOOST TEMPS IN THE UPPER TEENS NORTH TO
UPPER 20S SOUTH.

BAROCLINIC ZONE DEVELOPS NEAR THE IA/MO BORDER BACKING OUR FLOW
MORE OUT OF THE EAST OR NORTHEAST. UPPER LEVEL FLOW BUCKLES BY
FRIDAY AS SHORTWAVE ENERGY MOVING ACROSS THE NRN ROCKIES DIVES
SOUTHEAST TO THE SOUTHERN PLAINS. CONSENSUS AMONG THE MODELS IS TO
KEEP BETTER KINEMATIC AND THERMODYNAMIC FORCING SUPPRESSED SOUTH
OF IOWA INTO THE WEEKEND. HOWEVER...ECMWF IS A LITTLE FARTHER
NORTH...AND WITH GENERAL TROUGHINESS ALOFT OVER THE AREA FRIDAY
THROUGH SATURDAY...HAVE MAINTAINED SLIGHT CHC SNOW DURING THIS
PERIOD. WILL HAVE COLDER TEMPS AGAIN FOR THE WEEKEND...THOUGH NOT
AS COLD AS TODAY.

&&

.AVIATION...
15/18Z...WIDESPREAD VFR CONDITIONS WILL CONTINUE WITH UNRESTRICTED 
VSBYS AND CIGS THROUGH THIS EVENING.  CIRRUS WILL BEGIN TO STREAM 
OVERHEAD LATE TONIGHT INTO WEDNESDAY MORNING AS WAA INTENSIFIES.  
NORTHWEST SFC WINDS WL BECOME SOUTHERLY BY WEDNESDAY MORNING AS HIGH 
PRESSURE PASSES TO THE EAST.
&&

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

&&

$$

SHORT TERM...LEE
AVIATION...COGIL
LONG TERM...MOYER