Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 280451
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1151 PM CDT MON OCT 27 2014

.SHORT TERM /TONIGHT/...
ISSUED AT 328 PM CDT MON OCT 27 2014

MAIN CONCERN FOR TONIGHT IS PRECIP AND TO SOME EXTENT...TEMPS. AS OF
3 PM THE SURFACE LOW HAS LIFTED INTO NORTHEAST IOWA AND SHOULD LIFT
INTO WESTERN WI BY 00Z.  TRAILING COLD FRONT WILL TAKE A LITTLE
LONGER TO CLEAR THE AREA.  CURRENT SURFACE ANALYSIS HAS THE FRONT
CHARLES CITY TO JUST WEST OF IOWA FALLS TO AMES THEN BACK SOUTHWEST
TO ROUGHLY CRESTON.  THE FRONT WILL EXIT THE FAR SOUTHEAST EARLY
THIS EVENING...BETWEEN 00Z AND 03Z.  THERE IS SOME WEAK FORCING AND
INSTABILITY TIED TO THE FRONTAL BOUNDARY AND THIS WILL BE
RESPONSIBLE FOR SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO THROUGH
00Z.

NEXT THERE IS AN UPPER LEVEL LOW OVER WESTERN NORTH DAKOTA WITH AN
UPPER LEVEL TROUGH EXTENDING INTO THE PLAINS.  THIS UPPER LEVEL
SYSTEM WILL SHIFT ACROSS THE STATE TONIGHT...THROUGH 12Z.  THERE IS
ALSO SOME FORCING ASSOCIATED WITH THIS FEATURE AS WELL BUT NOT MUCH
INSTABILITY.  THAT IS MAINLY TIED TO THE FRONT.  I AM EXPECTING SOME
SHOWERS ALONG WITH LOWER CLOUDS MOVING IN LATER WITH THE UPPER
TROUGH PASSAGE.

EXPECT WINDS TO INCREASE BEHIND THE FROPA AND AHEAD OF THE UPPER
TROUGH.  THERE WILL BE A PERIOD THIS AFTERNOON INTO EARLY EVENING
WITH WIND SPEEDS 15G25 MPH BEFORE DIMINISHING SOME THIS EVENING AND
OVERNIGHT.  STRONG COLD ADVECTION WILL OCCUR LATE TONIGHT BUT MORE
SO ON TUESDAY.  WINDS WILL AGAIN INCREASE AROUND DAYBREAK BUT
ESPECIALLY TUESDAY MORNING AND A STRATOCU DECK WILL BE MOVING IN
FROM THE NORTHWEST AROUND THIS TIME.  LOWER CLOUDS SHOULD NOT MAKE
IT VERY FAR INTO THE FORECAST AREA BY 12Z BUT THE WINDS SHOULD
PRODUCE ENOUGH MIXING TO PREVENT TEMPS FROM COMPLETELY BOTTOMING
OUT.

TEMPS WILL VARY A FAIR AMOUNT HOWEVER WITH UPPER 30S IN THE FAR NW
CWA BUT ACROSS THE SOUTHEAST TEMPS WILL STILL BE FAIRLY MILD WITH
LOWS EXPECTED IN THE MID TO UPPER 40S.

.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 328 PM CDT MON OCT 27 2014

LONG TERM FORECAST PERIOD BEGINS RELATIVELY QUIET AND BECOMES ACTIVE
BY ITS CONCLUSION. ON TUESDAY MORNING THE STRATUS/STRATOCU DECK
ASSOCIATED WITH THE DEPARTING SYSTEM WILL SPREAD SOUTHWARD. BKN
CONDITIONS ARE EXPECTED AS FAR SOUTH AS US 20/I-80 ZONE PER NAM/RAP
GUIDANCE. COMBINATION OF CLOUDS AND CAA WILL HELP KEEP TEMPERATURES
TO NOTABLY LOWER LEVELS THAN THOSE SEEN THE PAST FEW DAYS. EVEN
AREAS WITH MORE SUNSHINE IN THE SOUTHERN CWA WILL SEE NOTICEABLY
COOLER TEMPS. WINDS WILL BE ELEVATED AS WELL WITH GUSTS IN THE 20 TO
30 MPH RANGE...HIGHEST ACROSS THE NORTH...BUT BELOW ADVISORY
CRITERIA.

WEDNESDAY WILL BE RELATIVELY QUIET WITH THE CWA BEING BETWEEN THE
DEPARTING WX SYSTEM AND THE NEXT ONE DROPPING SE FROM CANADA. THIS
SYSTEM WILL BE CLIPPER-LIKE...MOVING RELATIVELY QUICKLY AND
BRINGING A BRIEF PERIOD OF ELEVATED MOISTURE AND FORCING. MODELS
HAVE COME INTO CLOSER AGREEMENT REGARDING TIMING AND STRENGTH OF
THIS SYSTEM. THEY HAVE ALSO CONTINUED THEIR FLIP FLOPPING
TREND...WITH BLEND SHOWING SLIGHT CHANCES. HAVE REMOVED THEM FOR
CONSISTENCY AND WILL LET SUBSEQUENT SHIFTS INSERT IF CONFIDENCE
INCREASES.

WX SYSTEM LATE WEEKEND INTO EARLY NEXT WEEK IS BECOMING MORE OF THE
FOCUS IN THE LONG TERM PERIOD. MODELS ARE TRENDING WETTER THAN
PREVIOUS. WESTERN CONUS RIDGE WILL PROGRESS EASTWARD INTO THE
CENTRAL U.S. HELPING FACILITATE A WARMUP IN TEMPERATURES. FORCING IN
CONJUNCTION WITH THE TAILING TROF IS EXPECTED TO RESULT IN A BROAD
AREA OF LIGHT PRECIP BY SUNDAY NIGHT/MONDAY MORNING FROM THE KS/OK
AREA INTO THE GREAT LAKES. FORCING BECOMES MORE COHERENT BY MONDAY
EVENING...BUT BY THEN THE SYSTEM WILL BE PULLING EASTWARD. ATTM AM
NOT CONCERNED ABOUT TSRA GIVEN RELATIVELY WEAK PROGGED INSTABILITY
VALUES.

&&

.AVIATION...28/06Z
ISSUED AT 1150 PM CDT MON OCT 27 2014

COLD FRONT HAS MOVED THROUGH ALL TAF SITES...SHIFTING ALL WINDS
OUT OF THE WEST AND NORTHWEST. POSSIBLE MVFR CEILINGS WILL MOVE
INTO NORTHERN TAF SITES...INCLUDING KMCW KALO AND KFOD NEAR 12Z.
CEILINGS AROUND 3 TO 4KFT EXPECTED MUCH OF TUESDAY ALONG WITH
GUSTY WESTERLY WINDS 20 TO 25KTS.

&&

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

$$

SHORT TERM...FAB
LONG TERM...ZOGG
AVIATION...CURTIS



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