Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 252027
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
327 PM CDT SAT APR 25 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 327 PM CDT SAT APR 25 2015

SYSTEM CURRENTLY PASSING JUST NORTH OF ST. LOUIS WILL CONTINUE TO
PUSH EAST OVERNIGHT AS SURFACE RIDGE BUILDS INTO THE UPPER MIDWEST.
DRY NORTHEAST FLOW IS EXPECTED TO PERSIST OVERNIGHT ACROSS THE STATE
WITH AIR IN THE SOURCE REGION RELATIVELY DRY. THIS DRIER AIR IS
ALREADY IN NORTHERN IOWA WHERE SKIES HAVE BECOME PARTLY SUNNY THIS
AFTERNOON AND THE WARMEST TEMPERATURES IN THE STATE EXIST WITH
READINGS IN THE MID TO UPPER 50S. THIS AIR WILL ADVECT SOUTHWEST
TONIGHT ERODING AWAY THE LOWER CLOUDINESS WITH CLEAR SKIES IN MOST
AREAS BY DAYBREAK. TEMPERATURES WILL DROP NICELY AS SKIES CLEAR
AND DRIER AIR WORKS INTO THE STATE WITH SOME PATCHY FROST POSSIBLE
IN THE NORTHEAST...ALTHOUGH LIKELY LIMITED IN COVERAGE GIVEN WINDS
WILL REMAIN AROUND 5 TO 8 MPH.

.LONG TERM /SUNDAY THROUGH SATURDAY/...
ISSUED AT 327 PM CDT SAT APR 25 2015

THE LONG TERM FORECAST IS OVERALL DRY AND QUIET WITH GRADUALLY
MODERATING TEMPERATURES. AT 500 MB...A RIDGE WILL BUILD ACROSS THE
CENTRAL U.S. ON SUNDAY AND MONDAY BEFORE BEING INTERRUPTED BY A
MODEST TROUGH PASSAGE AROUND TUESDAY. SUBSEQUENT TO THIS A
STRONGER RIDGE WILL BUILD ACROSS THE WESTERN AND CENTRAL U.S FOR
THE REMAINDER OF THE WEEK.

AT THE SURFACE...A CORRESPONDING RIDGE WILL BUILD ACROSS OUR
REGION FROM SUNDAY INTO TUESDAY PLACING US IN FAIRLY LIGHT
GENERALLY NORTH TO NORTHEAST FLOW. THIS WILL KEEP CONDITIONS CLEAR
AND DRY...BUT ABSENT ANY NOTABLE TEMPERATURE ADVECTION WE SHOULD
SEE A SLOW BUT STEADY WARMING TREND AS EVER INCREASING INSOLATION
MODIFIES THE AIRMASS IN PLACE. A WEAK SURFACE TROUGH...REFLECTING
ITS ATTENDANT 500 MB REFLECTION...WILL TRAVERSE IOWA LATE ON
TUESDAY AND THE ECMWF IS ATTEMPTING TO SPIT OUT SOME VERY LIGHT
QPF. HOWEVER...FORECAST SOUNDINGS INDICATE SUBSTANTIAL DRY AIR AND
A RELATIVE LACK OF INSTABILITY SO PRECIPITATION APPEARS PRETTY
UNLIKELY AND HAVE HELD MENTION OUT OF THE FORECAST FOR NOW.

LATER THIS WEEK...FROM THURSDAY THROUGH SATURDAY...MOST LONG RANGE
SOLUTIONS POINT TO PERSISTENT RIDGING ALOFT AS MENTIONED ABOVE
ALONG WITH SOUTH TO SOUTHWEST WINDS IN THE LOWER LEVELS. WHILE
THERE IS SOME POTENTIAL FOR THE 500 MB RIDGE TO FLATTEN OUT AND
ALLOW ONE OR MORE SHORTWAVES TO INTERRUPT THIS PATTERN...MOST
INDICATIONS ARE THAT THE RIDGING WILL HOLD UP AND ALLOW FOR
SEVERAL DAYS OF STEADY WARMING TO END THE WEEK. HAVE STAYED CLOSE
TO MODEL GUIDANCE CONSENSUS ON TEMPERATURES FOR NOW...BUT IF THIS
SIGNAL HOLDS OVER THE NEXT COUPLE OF DAYS THESE FORECAST HIGHS MAY
NEED TO WARM FURTHER. EVEN IF THE FLATTER RIDGE AND ASSOCIATED
SHORTWAVES PAN OUT INSTEAD...TEMPERATURES SHOULD STILL WARM PRETTY
NICELY AND RAIN CHANCES WOULD REMAIN FAIRLY LOW GIVEN AN ABSENCE
OF A GOOD MOISTURE SOURCE OR STRONG FORCING MECHANISM.

&&

.AVIATION...25/18Z
ISSUED AT 100 PM CDT SAT APR 25 2015

UPPER SYSTEM PASSING THROUGH MISSOURI AND WILL CONTINUE TO PULL
EAST OVERNIGHT INTO SUNDAY. DRIER NORTHEAST FLOW IS EXPECTED TO
PERSIST INTO THE STATE OVERNIGHT WHICH WILL EVENTUALLY ERODE AWAY
THE LOW CEILINGS IN SOUTHERN IOWA THIS EVENING INTO THE OVERNIGHT
WITH VFR CONDITIONS BECOMING MORE PROMINENT. THE VFR CONDITIONS
WILL PERSIST INTO SUNDAY.

&&

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

&&

$$

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


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