Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 211138
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
637 AM CDT TUE OCT 21 2014

.SYNOPSIS....HIGH PRESSURE RIDGE FROM ONTARIO THROUGH IA INTO TX
WILL MOVE EAST WITH FLOW BECOMING SELY.  FRONTAL SYSTEM WILL MOVE
THROUGH THE ROCKIES AND PASS THROUGH THE UPPER MIDWEST WEDNESDAY
NIGHT AND THURSDAY.

&&

.SHORT TERM /TODAY/...
ISSUED AT 355 AM CDT TUE OCT 21 2014

HIGH PRESSURE RIDGE OVER IA THIS MORNING WILL DRIFT TO THE EAST WITH
WINDS GRADUALLY BECOMING SELY THIS AFTERNOON.  MORNING LOWS WILL
START OUT LOWER THAN YESTERDAY.  THAT IN COMBINATION WITH LOWER 1000-
925 MB THICKNESS VALUES AND SELY FLOW OUT OF THE HIGH PRESSURE RIDGE
WILL YIELD COOLER TEMPS THAN YESTERDAY...ESPECIALLY OVER THE NERN
ZONES  KEPT HIGHS IN THE UPPER 50S AND 60S TODAY VS THE 65 TO 75
DEGREE READINGS OF YESTERDAY.  SKIES WILL REMAIN MOSTLY CLEAR TODAY
WITH NO REAL MOISTURE RETURN AND ONLY WEAK WAA ALOFT.

.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 355 AM CDT TUE OCT 21 2014

MAIN FOCUS WAS ON RAIN CHANCES WEDNESDAY NIGHT INTO THURSDAY AND
TEMPERATURES FRIDAY THROUGH THE WEEKEND. LEANED TOWARD THE SLOWER
ECMWF 21.00Z SOLUTION WRT TO THE FRONT MOVING THROUGH THE REGION MID-
WEEK AND ALSO OVER THE WEEKEND AS WELL AS IT WAS THE SLIGHTLY WARMER
OF THE EXTENDED MODELS.

TONIGHT THROUGH THURSDAY...UPPER LEVEL RIDGE MOVES OVERHEAD WITH A
SURFACE HIGH SHIFTING EAST TONIGHT INTO WEDNESDAY ALLOWING FOR SOME
FAIRLY STRONG WAA ALOFT TOMORROW AHEAD OF NEXT SHORTWAVE TROUGH
EJECTING OUT OF THE NORTHERN ROCKIES. ECMWF/GFS HAVE SLOWED SYSTEM
DOWN ENTERING THE FORECAST AREA BUT STILL LOOKS TO BE A QUICK MOVING
SYSTEM ACROSS THE STATE. IMPRESSIVE MOISTURE TRANSPORT INTO THE
STATE AND PRECIPITABLE WATER VALUES RISE TO 1.00 TO 1.25 INCHES FOR
MUCH OF THE CENTRAL IOWA. THIS IS ABOUT TWO STANDARD DEVIATIONS
ABOVE NORMAL FOR THIS TIME OF YEAR. STRONGEST FORCING AND DEEPEST
MOISTURE MOVE ACROSS THE FORECAST AREA FROM 03Z TO 12Z
THURSDAY...WITH SOME LINGERING RAIN ACROSS THE EASTERN SECTIONS OF
THE FORECAST THROUGH 18Z THURSDAY. THUNDERSTORM POTENTIAL AS WELL AS
SEVERE POTENTIAL LOOK MINIMAL WITH VERY LIMITED INSTABILITY
AVAILABLE...BUT ANYTHING PRESENT WILL BE CONFINED OVER SOUTHERN
IOWA. KEPT THE THUNDER MENTIONED IN THIS LOCATION.

FRIDAY INTO MONDAY...UPPER LEVEL RIDGE BUILDS INTO THE CENTRAL U.S.
BY FRIDAY WITH IOWA PLACED WEST OF A WEAK SURFACE HIGH. LOOKS TO BE
ENOUGH MIXING AND WAA ON THE BACKSIDE OF THE SURFACE HIGH TO PUT MAX
TEMPERATURES INTO THE 70S. 850MB TEMPERATURES RISE TO +14C TO +17C
ACROSS IOWA BY THE AFTERNOON. AS A RESULT...WARMED MAX TEMPERATURES
UP 1-3 DEGREES OVER MUCH OF THE FORECAST AREA. EVEN STRONGER WAA AND
MIXING ON SUNDAY AS 850MB TEMPERATURES RISE TO +16 TO +18C. TWEAKED
MAX TEMPERATURES UP SUNDAY AS WELL.

&&

.AVIATION...21/12Z
ISSUED AT 632 AM CDT TUE OCT 20 2014

HIGH PRESSURE RIDGE WILL BRING CLEAR SKIES AND LIGHT WINDS TO
THE AREA TODAY  LIGHT AND VARIABLE WINDS WILL BECOME EAST TO
SOUTHEAST AROUND 10 KTS BY TONIGHT.

OUTLOOK...FRONTAL SYSTEM WILL MOVE OUT OF THE ROCKIES ON
WEDNESDAY.  THIS FRONT WILL BRING WIDESPREAD RAIN TO THE AREA
WEDNESDAY NIGHT INTO THURSDAY.  CONDITIONS WILL DETERIORATE TO
MVFR AND SOME IFR WED NIGHT INTO THU.  HIGH PRESSURE WILL BRING
CLEARING FROM THE WEST LATE THU WITH VFR CONDITIONS BY THU NIGHT
INTO FRIDAY.

&&

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

&&

$$

SYNOPSIS...MS OCT 14
SHORT TERM...MS OCT 14
LONG TERM...KLP
AVIATION...MS OCT 11



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