FXUS63 KDMX 281729 AAA
AFDDMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1128 AM CST SAT NOV 28 2009

...UPDATED AVIATION DISCUSSION...

.SHORT TERM /TODAY/...
LITTLE OF CONCERN AGAIN TODAY.  08Z SFC ANLYS PLACES WARM FRONT 
ALONG KCIN/KDSM/KOOA LINE WITH READINGS FROM THE UPPER 20S NORTH TO 
NEAR 40 SOUTH.  AIRMASS REMAINS QUITE DRY BUT LACK OF STRONGER WINDS 
WILL LIMIT MIXING SOMEWHAT...MUCH LIKE YESTERDAY.  THIS...ALONG WITH 
POTENTIAL FOR PATCHY EARLY MORNING FOG NORTH OF WARM FRONT...SHOULD 
KEEP TEMPS REBOUNDING TOO MUCH TODAY AND WILL RESULT IN ANOTHER 
DECENT MAX TEMP GRADIENT FROM NE-SW.  SUGGESTIONS FROM BUFR 
SOUNDINGS REFLECT THIS THINKING AS WELL SO HAVE HIGHS AT OR JUST 
BELOW COOLER END OF GUIDANCE.

.LONG TERM /TONIGHT THROUGH FRIDAY/...
FORECAST ISSUE THIS MORNING IN THE LONG TERM IS TIMING OF FRONTS AND 
TEMPERATURES.  UPPER TROUGH NEAR ALBERTA THIS MORNING IS FORECAST TO 
MOVE SOUTHEAST INTO THE GREAT LAKES BY MONDAY.  PREFER THE 00Z GFS 
OVER THE 00Z NAM CONCERNING THE SPEED AND DEPTH OF THE UPPER 
TROUGH.  THE 00Z GFS IS FASTER AND FLATTER WITH UPPER TROUGH WHICH 
MAKE MORE SENSE GIVEN THE POSITIVE TILT OPEN WAVE NATURE OF THE 
TROUGH. SOME COLD AIR WILL ADVECT SOUTH ACROSS IOWA SUNDAY BEHIND 
THE ASSOCIATED COLD FRONT.  THE NEXT UPPER TROUGH FORECAST TO ARRIVE 
MID WEEK LOOKS STRONGER AND IT SHOULD DRAG DOWN EVEN COLDER AIR INTO 
IOWA.  AIRMASS DRY INITIALLY WITH FIRST SHORT WAVE. DURATION AND 
MAGNITUDE OF THE FORCING ASSOCIATED WITH THIS WAVE SHOULD NOT BE 
ENOUGH TO GENERATE PCPN SO KEPT DRY FORECAST GOING. 

SHOULD HAVE SOME SC ON SUNDAY BEHIND THE FRONT WHICH IS FORECAST TO 
MOVE THROUGH TONIGHT.  ENOUGH CAA TO DROP HIGHS 10 DEGREES OR A 
LITTLE MORE VS SATURDAY.  WESTERLY 850 MB AND SURFACE FLOW EARLY 
NEXT WEEK AHEAD OF NEXT COLD FRONT SUPPORTS WARM-UP.  TUESDAY/S 
TEMPS MIGHT NEED ADJUSTED UPWARD DEPENDING ON FRONTAL TIMING AND 
AMOUNT OF WARM AIR AVAILABLE.  WESTERLY FLOW THIS TIME OF YEAR 
CERTAINLY SUPPORTS WARMER TEMPS.  COLD AIR BEHIND COLD FRONT TUESDAY 
NIGHT LOOKS COLDER THAN THE AIRMASS CHANGE TONIGHT AND SUNDAY.  
CURRENT FORECAST REASONABLE CAPTURING THE DOWNWARD TREND IN 
TEMPERATURES LATE NIGHT WEEK. 

&&

.AVIATION...
28/18Z...WEAK COLD FRONT MOVING THROUGH THE SOUTHEAST HALF OF 
CENTRAL IOWA THIS AFTN. VFR AND WEAK WINDS FOR THE FIRST 12 HOURS OF 
THE FORECAST.  NNWLY FLOW DOES INCREASE LATER TONIGHT AND MAY 
DEVELOP MVFR STRATUS. CONFIDENCE IN THE STRATUS HAS RISEN SOME...SO 
HAVE INCLUDED BKN020-025 CEILINGS AFT 12Z.

&&

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

&&

$$

SHORT TERM...SMALL
LONG TERM...JOHNSON
AVIATION...MOYER