000
FXUS63 KDMX 081741 AAA
AFDDMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1141 AM CST SUN NOV 8 2009

.SHORT TERM...TODAY
MAIN FORECAST CONCERN IS WITH WARM FRONT OUT AHEAD OF THE LOW 
PRESSURE SYSTEM THAT WILL TRACK ACROSS THE CENTRAL PLAINS TODAY AND 
TONIGHT.  STATIONARY FRONT CURRENTLY STRETCHED ACROSS NORTHERN 
MISSOURI INTO SOUTHEAST IOWA WILL SHIFT NORTHWARD AS THE LOW 
APPROACHES FROM THE WEST TODAY.  BIGGEST QUESTION IS HOW FAR NORTH 
AND HOW QUICKLY WILL IT MOVE NORTHWARD TODAY...WHICH WILL PLAY A 
ROLE IN HIGH TEMPS TODAY...MAINLY ACROSS THE NORTHERN CWA. BOTH 
NAM/GFS HAVE FRONT REACHING THE NORTHERN IOWA BORDER BY THE EARLY 
AFTERNOON.  BUFR SOUNDING FORECAST HIGH CLOUD DECK STICKING AROUND 
FOR MUCH OF THE PEAK HEATING PERIOD ACROSS NORTHERN IOWA...WHICH 
SHOULD HINDER HIGH TEMPS FROM GETTING TOO WARM. HOWEVER...WITH 
DECENT WAA BEHIND FRONT...STILL WENT AT OR SLIGHTLY ABOVE GUIDANCE 
ACROSS NORTHERN IOWA FOR HIGHS TODAY. OVER CENTRAL AND SOUTHERN 
PORTIONS OF THE CWA...HIGH CLOUD DECK SHOULD BE OVERCOME BY STRONGER 
WAA AS 850MB TEMPS RANGE AROUND +15-16C...SO MORE CONFIDENT WITH 
GOING ABOVE GUIDANCE IN THIS AREA.  WINDS LOOK TO BE STRONGEST 
ACROSS THE SOUTH AS WELL WITH THEM MIXING DOWN FROM AROUND 900MB TO 
AROUND 20 TO 25KTS.  

.LONG TERM...TONIGHT THROUGH SATURDAY
PRECIPITATION CHANCES TONIGHT THROUGH MONDAY NIGHT REMAIN THE 
PRIMARY FORECAST CHALLENGE DURING THROUGH MID WEEK. LOW PRESSURE 
LIFTING NORTHEAST THROUGH NORTHWEST IOWA WILL BEGIN TO DRAG A COLD 
FRONT THROUGH IOWA OVERNIGHT AS THE SYSTEM MOVES INTO SRN MN. THE 
BOUNDARY IS EXPECTED TO BE OVER THE FAR SOUTHEASTERN PORTION OF THE 
FORECAST AREA BY 12Z MONDAY. DESPITE SOME MOISTURE ADVECTION AHEAD 
OF THE BOUNDARY...PRECIPITATION CHANCES WILL BE QUITE LOW DUE TO A 
PRONOUNCED DRY WEDGE IN THE MID LEVELS FROM 800-500 MB. WEAK FORCING 
WILL BE PRESENT ABOVE THE DRY LAYER HOWEVER ANY HYDROMETERS FALLING 
INTO THE DRY AIR WILL MOSTLY EVAPORATE AND ANYTHING THAT DOES REACH 
THE SFC LIKELY WILL NOT BE MEASURABLE.

BETTER OVERALL MOISTURE DEPTH OVER THE FAR SOUTHEAST ON MONDAY WHERE 
THE SFC BOUNDARY STALLS IN THE VICINITY. THE WINDOW FOR 
PRECIPITATION OVER THE SOUTHEAST...WHICH IS MAINLY SOUTHEAST OF A 
LAMONI TO OTTUMWA LINE...IS RELATIVELY NARROW AT 3-6 HOURS. SOME 
CONVECTIVE INSTABILITY STILL POSSIBLE AND HAVE MAINTAINED THE ISOLD 
THUNDER MENTION IN THIS REGION. MOST OF THE FORECAST AREA VERY WELL 
COULD STAY DRY DURING THIS PERIOD.

THE NAM SOLUTION OF HANGING THE BOUNDARY UP INTO SOUTHEAST IOWA 
THROUGH TUESDAY DOES NOT APPEAR PLAUSIBLE WITH A LARGE AREA OF HIGH 
PRESSURE BUILDING IN FROM THE WEST. THEREFORE HAVE KEPT THE PERIOD. 
DRY. THE GFS MAV/MEX GUIDANCE STILL APPEARS TO BE HAVING ISSUES FOR 
TUESDAY...SUGGESTING HIGHS IN THE LOW TO MID 60S WHILE ITS OWN BUFR 
SOUNDINGS ALONG WITH OTHER GUIDANCE ARE NEARLY 10 DEGREES COOLER. 
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH WED THEN RETURN FLOW 
ARRIVES ON THE BACK SIDE OF THE SYSTEM ON THURSDAY. HAVE INCREASED 
HIGH TEMPERATURES ON THURSDAY WITH THE GOOD SOUTHERLY FLOW EXPECTED. 
UNSETTLED WEATHER MAKES A RETURN TOWARD THE END OF THE PERIOD.

&&

.AVIATION...08/18Z
SFT LOW OVR NERN NEBRASKA WITH WRMFNT XTNTG EWD INTO SRN WI WILL LFT 
NEWD THIS AFTN.  GUSTY SLY WNDS IN THE WRM SECTOR WILL DMSH OVR NWRN 
IA BY MID AFT OR SO AND ARND SNST OVR THE REST OF THE AREA.  CDFNT 
WILL SWEEP ACRS THE TAF SITES TNGT SHFGT WNDS TO THE NW ARND 10 
KTS.  GUD VFR WX XPCTD THRU TAF PD WITH INC MID CLDS AND WNDS 
SWINGING ARND TO NLY ON MON.

&&

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

&&

$$

SHORT TERM...MS NOV 09
LONG TERM...DONAVON
AVIATION...MS NOV 09