FXUS63 KDMX 272050
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
250 PM CST FRI NOV 27 2009

.SHORT TERM /TONIGHT/...
TONIGHT...A QUIET NIGHT IS IN STORE WITH RIDGING ALOFT...WEAK FLOW 
IN THE LOW LEVELS...AND ONLY SOME CIRRUS CLOUDS OVERHEAD THAT WILL 
CLEAR OUT THIS EVENING EXCEPT PERHAPS ACROSS OUR NORTHERN COUNTIES. 
PRIMARY FORECAST CHALLENGE FOR TONIGHT IS MINIMUM TEMPERATURES. 
CONDITIONS APPEAR EXCELLENT FOR RADIATIONAL COOLING SIMILAR TO LAST 
NIGHT. DEWPOINTS ARE HIGHER TODAY...HOWEVER JUST TO OUR WEST A WEAK 
SURFACE TROUGH IS BRINGING MUCH LOWER DEWPOINTS INTO NORTHEASTERN 
NEBRASKA AND SOUTHEASTERN SOUTH DAKOTA AND THESE MAY REACH OUR 
WESTERN AND NORTHWESTERN AREAS LATER TONIGHT...ALONG WITH DEAD CALM 
WINDS NEAR THE TROUGH AXIS. EVEN WITH THE SOMEWHAT HIGHER CURRENT 
DEWPOINTS AND TEMPERATURES THAN AT THE SAME TIME YESTERDAY...MOS 
NUMBERS LOOK OVERDONE TONIGHT ESPECIALLY IN OUR WEST AND SOUTHWEST. 
HAVE TRIMMED SEVERAL DEGREES OFF OF PREVIOUS FORECAST AND AM NOW 
NEAR OR UNDER MOS AVERAGE ACROSS THE BOARD. IF DEWPOINTS FALL AFTER 
DARK AS EXPECTED THEN EVEN THESE COULD BE TOO HIGH...PARTICULARLY IN 
THE NISH VALLEY AND OUR NORTHERN COUNTIES. THERE WILL ALSO BE A 
POTENTIAL FOR FOG LATE TONIGHT...HOWEVER IT APPEARS THAT THIS WOULD 
LIKELY BE PATCHY AND NOT PARTICULARLY THICK SO WILL LEAVE MENTION 
OUT OF THE FORECAST AT THIS TIME.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
WILL SEE SFC TROF PASS THROUGH STATE ON SATURDAY...ALTHOUGH NORTH 
SIDE OF THERMAL RIDGE WILL STILL BE OVER THE STATE.  THEREFORE... 
TEMPS WILL ONCE AGAIN BE WELL ABOVE NORMAL FOR DAYTIME HIGHS.  WL 
SEE UPPER TROF APPROACH LATE SATURDAY NIGHT INTO SUNDAY WITH POST 
FRONTAL FORCING BUT LITTLE MOISTURE TO WORK WITH.  ANTICIPATE SOME 
CLOUDINESS BUT NOT MUCH IN THE WAY OF PCPN GIVEN THE LIMITED 
MOISTURE.  SYSTEM PASSES BY SUNDAY EVENING WITH COOLER AIR FILTERING 
INTO THE STATE INTO SUNDAY NIGHT.  HOWEVER...WAA BEGINS QUICKLY ON 
MONDAY WITH TEMPERATURES REBOUNDING MONDAY AFTERNOON INTO TUESDAY.  
BOTH GFS AND EURO HAVE A LARGE TROF DEVELOPING ACRS THE CENTRAL AND 
EASTERN PORTIONS OF THE UNITED STATES BY THE MIDDLE OF NEXT WEEK.  
MOISTURE WILL REMAIN SPARSE WITH SOUTHERN STREAM SYSTEM ABSORBING 
MUCH OF THE GULF MOISTURE.  MUCH COOLER AIR WILL PUSH INTO THE STATE 
BY WEDNESDAY AND CONTINUE THROUGH THE END OF THE WORK WEEK WITH 
REINFORCING SHOTS OF COOLER AIR.  THIS WILL BE THE COLDEST AIR OF 
THE SEASON SO FAR WITH HIGHS IN THE 30S AND LOWS IN THE TEENS AND 
20S.  

&&

.AVIATION...
27/18Z...MAINLY VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. WINDS 
WILL REMAIN SSE THIS AFTERNOON WITH CIRRUS PRODUCING CIGS AROUND 
FL250. AFTER SUNSET EXPECT CLEAR SKIES AND LIGHT AND VARIABLE WINDS 
WITH HIGH PRESSURE RIDGE MOVING OVERHEAD...AND POSSIBILITY OF MVFR 
FOG DURING THE EARLY MORNING HOURS SATURDAY.

&&

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

&&

$$

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