000
FXUS63 KDMX 132357
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
657 PM CDT SUN APR 13 2014

.UPDATE...
ISSUED AT 657 PM CDT SUN APR 13 2014

GOING FORECAST SEEMS ON TRACK WITH LITTLE CHANGE IN FORTHCOMING
UPDATE. SURFACE REPORTS AND WEBCAMS SUGGEST SNOW STICKING ON
ORGANIC OR ELEVATED SURFACES BUT ROADS MAINLY WET. PRIMARY CONCERN
WILL BE DRAMATICALLY REDUCED VISIBILITIES DUE TO STRONG NLY WINDS.
STILL EXPECT SOME ROAD ACCUMS AFTER SUNSET AS ROAD TEMPS CONTINUE
TO DROP...WITH ONE TO TWO INCH ACCUMS ON NON-ROADS NORTHWEST OF
CARROLL TO MASON CITY LINE...ISOLATED SPOTS TO THREE.

&&

.SHORT TERM /TONIGHT/...
ISSUED AT 356 PM CDT SUN APR 13 2014

COMPLEX SCENARIO THROUGH THE OVERNIGHT AS A STRONG SPRING LOW
PRESSURE SYSTEM OVER OKLAHOMA AND KANSAS LIFTS NORTHEAST THROUGH
MISSOURI AND CLIPPING INTO SOUTHEAST IOWA BEFORE RAPIDLY LIFTING
INTO THE CENTRAL GREAT LAKES BY MONDAY MORNING. INSTABILITY
CONTINUES TO LIFT INTO SOUTHERN IOWA AS STRONG MOISTURE TRANSPORT IS
MAINTAINED. MID LEVEL DRY SLOT MOVING INTO EASTERN KANSAS WILL PUSH
THE MOISTURE ADVECTION TO THE EAST AND SHOULD BE EAST OF THE
FORECAST AREA BY 00Z. LINEAR CONVECTION HAS DEVELOPED JUST EAST OF
THE DRY SLOT AND IT MAY GLANCE THE VERY FAR SOUTHEAST OTHERWISE NO
SEVERE WEATHER IS EXPECTED ACROSS CENTRAL IOWA. HEAVY RAIN HAS BEEN
OCCURRING TODAY ESPECIALLY NEAR WATERLOO THROUGH TAMA COUNTY AND BACK
TOWARD CLARKE COUNTY. POTENTIAL FOR AN INCH OR MORE YET BEFORE THE
PRECIPITATION INTENSITY DIMINISHES. THE STRONG MOISTURE TRANSPORT
AND PWAT VALUES NEAR 200 PERCENT OF CLIMO HAS LED TO THE EFFICIENT
PRECIPITATION. DESPITE THE VERY DRY PERIOD PRECEDING THIS
EVENT...THESE RAINFALL AMOUNTS WILL LEAD TO SIGNIFICANT RUNOFF AND
RISES ALONG STREAMS. SIGNIFICANT PONDING AND SOME FLOODING IS
POSSIBLE THEREFORE HAVE ADDED A FLOOD WATCH THROUGH 06Z.

FARTHER NORTH...COLD AIR CONTINUES TO SPILL SOUTH INTO IOWA WITH A
TRANSITION FROM RAIN TO SNOW BEGINNING. THE BIGGEST CHALLENGE FOR
THE PERIOD IS SNOWFALL AMOUNTS OVERNIGHT. POTENTIAL BANDING POSSIBLE
WITH A FRONTOGENETICAL BAND DEVELOPING OVER THE NORTHWEST THIRD OF
THE FORECAST AREA. POSSIBLE FOR SEVERAL INCHES OF SNOW ESPECIALLY ON
GRASSY AREAS BUT IF IT SNOWS LONG ENOUGH...SNOW COVERED ROADS MAY
OCCUR. TO COMPLICATE MATTERS IS VERY STRONG NORTH WINDS DEVELOPING
AT 25 TO 35 MPH WITH GUSTS TO 50 MPH. AM CONCERNED COULD HAVE A
PERIOD OF BLOWING SNOW THAT MAY WARRANT A WINTER WEATHER ADVISORY.
AT THIS TIME HAVE STAYED WITH WIND HEADLINES WITH THE OPTION TO
UPGRADE IF NECESSARY.

.LONG TERM /MONDAY THROUGH SUNDAY/...
ISSUED AT 356 PM CDT SUN APR 13 2014

LIGHT RAIN AND SNOW WILL EXIT TO THE SOUTHEAST ON MONDAY
MORNING...WITH MUCH COOLER AIR FLOWING INTO THE STATE THROUGH
TUESDAY MORNING WHEN LOWS WILL BE IN THE LOW TO MID 20S AND A FEW
AREAS MAY SNEAK INTO THE UPPER TEENS...ESPECIALLY IF THERE IS ANY
SNOW ON THE GROUND AS DISCUSSED ABOVE IN THE SHORT TERM. OTHER THAN
THE COLD OUR WEATHER WILL REMAIN QUIET ACROSS THE AREA INTO THE
MIDDLE OF THE WEEK...WITH A WARMING TREND BEGINNING TUESDAY
AFTERNOON AS SOUTHERLY FLOW RETURNS AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM AND WARMER TEMPERATURES COME IN ALOFT. AS THIS LOW
PRESSURE SYSTEM DEVELOPS ON TUESDAY AND TUESDAY NIGHT IT WILL
RECENTER OVER THE SOUTHERN HIGH PLAINS...WITH AN INVERTED TROUGH
EXTENDING UP ACROSS NEBRASKA AND ACROSS THE NORTHWEST CORNER OF IOWA
INTO MINNESOTA. ON TUESDAY NIGHT AND WEDNESDAY MORNING THIS WILL
RESULT IN STRENGTHENING SOUTHERLY FLOW AND STRONG WARM AIR ADVECTION
ACROSS CENTRAL IOWA...AND HAVE CONTINUED TREND OF INCREASING
TEMPERATURES DURING THIS PERIOD WITH NO POPS.

UNFORTUNATELY THE BRIEF PERIOD OF WARM AND DRY WEATHER FROM TUESDAY
AFTERNOON INTO WEDNESDAY WILL COME TO AN ABRUPT END AS THE
AFOREMENTIONED INVERTED TROUGH MOVES ACROSS THE AREA AS A COLD
FRONT...BRINGING LOWER TEMPERATURES AND PROLONGED RAIN CHANCES
ACROSS THE AREA FROM LATE WEDNESDAY THROUGH THURSDAY NIGHT. THE RAIN
MAY CHANGE TO SNOW AT TIMES ACROSS OUR NORTH AND NORTHWEST DURING
THE LATE NIGHT/EARLY MORNING HOURS EACH DAY AND OVERALL IT WILL BE
COOL...GRAY AND WET DURING THIS PERIOD. LOOKING TOWARD NEXT WEEKEND
THERE ARE STILL SOME SLIGHT CHANCES FOR RAIN BUT GENERALLY IT LOOKS
DRY AND GETTING WARMER EACH DAY...WITH TEMPERATURES WELL INTO THE
60S BY NEXT SUNDAY.

&&

.AVIATION...14/00Z
ISSUED AT 657 PM CDT SUN APR 13 2014

CONDITIONS VARY FROM MVFR/IFR SE TO IFR/LIFR NW WITH MOST
DEGRADATION IN SNOW AREAS JUST NORTH AND WEST OF KFOD. EXPECT
SIMILAR TRENDS THROUGH THE NIGHT AS RAIN SNOW LINE GRADUALLY
PUSHES SOUTH AND EAST. PRECIP SHOULD END 07Z-11Z FOLLOWED BY
SEVERAL HOURS OF CONTINUED MVFR CIGS...THEN TRANSITION TO VFR
THROUGH MUCH OF THE DAY MON. NLY WINDS WILL REMAIN STRONG
OVERNIGHT WITH GUSTS OFTEN WELL INTO THE 30S /KTS/ BEFORE
DIMINISHING ONLY SLIGHTLY MON.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR ADAIR-ADAMS-AUDUBON-
BOONE-CALHOUN-CARROLL-CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-
EMMET-FRANKLIN-GREENE-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
KOSSUTH-MADISON-PALO ALTO-POCAHONTAS-POLK-RINGGOLD-SAC-STORY-
TAYLOR-UNION-WARREN-WEBSTER-WINNEBAGO-WORTH-WRIGHT.

FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR APPANOOSE-BLACK HAWK-
DAVIS-DECATUR-GRUNDY-JASPER-LUCAS-MAHASKA-MARION-MARSHALL-MONROE-
POWESHIEK-TAMA-WAPELLO-WAYNE.

&&

$$

UPDATE...SMALL
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...SMALL