FXUS63 KDMX 261145
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
544 AM CST SAT DEC 26 2009

...UPDATED AVIATION DISCUSSION...

.SHORT TERM.../TODAY/
LOW PRESSURE OVER SOUTHWEST IOWA...CENTERED NEAR CRESTON...IS 
CONTINUING TO FILL AND WEAKEN. SOME LIGHT SNOW IS STILL 
ONGOING...MAINLY TO THE EAST AND NORTHEAST OF THE SFC FEATURE WHILE 
DRIER AIR IS MOVING WEST SOUTHWEST OUT OF WISCONSIN AND INTO THE 
NORTHEAST PART OF THE STATE. SOME OF THE SNOW WILL LIKELY LINGER 
OVER THE SOUTHEAST AFTER 12Z WITH MINOR ADDITIONAL ACCUMULATIONS 
POSSIBLE BEFORE ENDING. FARTHER TO THE WEST...LIGHT SNOW REMAINS 
HOWEVER VISIBILITIES HAVE BEEN REMAINING 5SM OR GREATER INCLUDING 
WITHIN THE CURRENT WINTER STORM WARNING AREA. WILL BE DROPPING THIS 
HEADLINE WITH THIS MORNINGS PACKAGE ISSUANCE. WILL BE DROPPING THE 
WINTER WEATHER ADVISORY AS WELL. AS MENTIONED SOME MINOR ADDITIONAL 
ACCUMULATIONS ARE POSSIBLE THOUGH LITTLE IMPACT IS EXPECTED FROM THE 
LIGHT FLUFFY SNOW CURRENTLY ONGOING. 

HIGH TEMPERATURES TODAY WILL BE COLD WITH HIGHS GENERALLY IN THE 20 
TO 25 DEGREE RANGE. DUE TO THE LOW PRESSURE CIRCULATION...OUR 
PRIMARY WEATHER TODAY WILL BE ORIGINATING FROM CENTRAL AND SRN 
WISCONSIN RESULTING IN WEAK LOW LEVEL COLD ADVECTION ALL DAY AND A 
REDUCTION IN PRECIPITATION CHANCES. THERE ARE CURRENTLY A FEW BREAKS 
IN THE CLOUDS OVER THIS REGION AS WELL...WHICH SHOULD REACH PORTIONS 
OF NORTH CENTRAL AND CENTRAL IA BY THIS AFTERNOON. 

.LONG TERM.../TONIGHT THROUGH FRIDAY/
SURFACE LOW FINALLY MOVES OFF INTO THE GREAT LAKES TONIGHT AND 
SUNDAY...BUT ONE MORE SPOKE WILL ROTATE SOUTHWARD AROUND THE UPPER 
LOW TONIGHT BEFORE THE PRECIPITATION EVENT IS OVER. ALL MODELS SHOW 
BEST FORCING TO BE WEST OF I-35 BEFORE MIDNIGHT TONIGHT AND THEN 
OVER SE HALF OF FORECAST AREA UNTIL MORNING. SATURATION ISN'T DEEP 
BUT IT IS WITHIN THE DENDRITIC THERMAL ZONE FOR A FEW HOURS...ENOUGH 
FOR HIGH CHANCE TO LIKELY POPS AND POSSIBLY AN INCH OR SO OF SNOW. 
COULD BE SOME FLURRIES SUNDAY BELOW THE INVERSION BUT NO 
ACCUMULATION EXPECTED. MODERATE WNW WINDS STAY UP INTO MONDAY... 
ALONG WITH WARM AIR NOSING IN ABOVE 850 MB. THIS WILL KEEP TEMPS 
FROM GETTING TOO COLD THROUGH MONDAY...BUT HIGH PRESSURE MOVES 
ACROSS THE AREA MONDAY NIGHT. LIGHT WINDS NEAR THE HIGH SHOULD ALLOW 
LOWS TO DROP BELOW ZERO OVER THE WEST AND NORTH. 

BY TUESDAY NIGHT AND WEDNESDAY...A WEAK SHORT WAVE IN THE NORTHERN 
STREAM BEGINS TO PHASE WITH A MUCH STRONGER SOUTHERN STREAM SHORT 
WAVE...BUT MOST OF THE ACTION WILL TAKE PLACE EAST OF IOWA. NET 
RESULT WILL BE A LOW PRESSURE SYSTEM ALONG THE CANADIAN BORDER AND A 
PACIFIC COLD FRONT CROSSING IOWA WEDNESDAY...WHILE A BIGGER SYSTEM 
CRANKS UP ALONG THE GULF COAST. SLIGHT CHANCE TO CHANCE POPS IN 
PLACE FOR TUESDAY NIGHT AND WEDNESDAY WITH THIS FEATURE BUT ANY 
ACCUMULATIONS WOULD APPEAR TO BE LIGHT. NO CHANGES TO THU/FRI 
FORECAST BUT IT APPEARS THAT DEEPENING EASTERN U.S. SYSTEM WILL WRAP 
DOWN SOME COLDER AIR BEGINNING THURSDAY INTO THE NEW YEAR.

&&

.AVIATION...
26/12Z...LIGHT SNOW CONTINUES OVER THE SOUTHEAST INCLUDING KOTM 
THOUGH SHOULD BE ENDING THE NEXT FEW HOURS. MAINLY MVFR CONDITIONS 
OVER THE SOUTH WITH DRIER AIR WORKING SOUTHWEST FROM WISCONSIN OVER 
THE NORTH AND BRINGING SOME VFR CONDITIONS WITH SCATTERED MVFR 
STRATUS. THE DRYING SHOULD CONTINUE TO MOVE INTO THE REMAINDER OF 
THE SITES TODAY HOWEVER BREAKS COULD QUICKLY BECOME BKN MVFR. 
ADDITIONAL BREAKS POSSIBLE THIS EVENING BEFORE NEXT SYSTEM DIVES 
SOUTH OUT OF MINNESOTA OVERNIGHT. LIKELY WILL BRING MVFR CIGS AND 
SOME SNOW...MAINLY WEST OF INTERSTATE 35. 

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE

&&

$$

SHORT TERM...DONAVON
LONG TERM...JUNGBLUTH
AVIATION...DONAVON