000
FXUS63 KDMX 062317
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
517 PM CST FRI DEC 6 2013

.SHORT TERM /TONIGHT/...
ISSUED AT 332 PM CST FRI DEC 6 2013

MAIN CONCERN FOR TONIGHT AGAIN BECOMES TEMPERATURES AND WIND CHILL
VALUES ACROSS CENTRAL IOWA. AS LARGE AREA OF LOW PRESSURE CONTINUES
TO PULL EASTWARD...SURFACE HIGH WILL SLOWLY PUSH SOUTH INTO NORTHERN
PLAINS TONIGHT. AS HIGH PUSHES IN AND LOW RETREATS...SKIES WILL
REMAINING MOSTLY CLEAR AND WINDS WILL BECOME LIGHTER AS PRESSURE
GRADIENT RELAXES SOMEWHAT. HOWEVER...WINDS WILL REMAIN UP OVERNIGHT
WITHOUT DROPPING OFF ENTIRELY. THIS HELPS KEEP CENTRAL IOWA FROM A
RADIATIONAL COOLING NIGHT...HOWEVER...WITH STRONGER PUSH OF COLD AIR
FILTERING IN OVER STATE FROM SNOW COVERED DAKOTAS...WILL SEE VERY
COLD TEMPERATURES NONETHELESS. WITH WINDS REMAINING UP...WILL SEE
ANOTHER NIGHT OF BITTERLY COLD WIND CHILL VALUES...INTO THE TEENS
BELOW ZERO ACROSS MUCH OF THE CWA. HAVE ISSUED ANOTHER WIND CHILL
ADVISORY FOR THE NORTHERN PORTION OF THE CWA...WITH WIND CHILL
VALUES EXPECTED MUCH COLDER THAN LAST NIGHT. VALUES WILL REMAIN NEAR
-20 OUTSIDE OF THE ADVISORY AND MAY BRIEFLY SLIP BELOW FROM TIME TO
TIME...ESPECIALLY IN COUNTIES NEAR THE ADVISORY.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 332 PM CST FRI DEC 6 2013

VERY COLD START TO SATURDAY WITH ARCTIC HIGH PRESSURE MOVING INTO
THE STATE. WIND CHILL ADVISORY WILL LAST THOUGH 9 AM WHEN INCREASE
IN TEMPS WILL ALLOW VALUES TO CLIMB. WILL BEGIN TO SEE CLOUDS
OVERSPREAD THE STATE BY LATER IN THE AFTERNOON AHEAD OF SYSTEM
DROPPING INTO THE WESTERN UNITED STATES. BY SATURDAY NIGHT...
ISENTROPIC LIFT WILL INCREASE ACROSS THE PLAINS EARLY IN THE
EVENING AND SPREAD INTO IOWA OVERNIGHT. SATURATION WILL TAKE SOME
TIME...HOWEVER ANTICIPATE SNOW TO BEGIN IN THE NORTHWEST CWA
AROUND MIDNIGHT WITH SNOW SPREADING ACROSS THE WESTERN HALF OF THE
CWA TO NEAR INTERSTATE 35 BY DAYBREAK. ISENTROPIC LIFT WILL
PERSIST ACROSS THE ENTIRE FORECAST AREA ON SUNDAY BEFORE GRADUALLY
SHIFTING EAST ON SUNDAY NIGHT. MODELS CONTINUE TO SUPPORT A
RELATIVELY DEEP DENDRITIC LAYER AND DECENT SNOW GROWTH WITH GENTLE
LIFT FOR SEVERAL HOURS. ANTICIPATE SNOW RATIOS IN THE UPPER TEENS
TO AROUND 20:1 FOR THE EVENT WITH HIGHEST RATIOS IN THE NORTH.
THIS PRODUCES AROUND 2 INCHES IN THE FAR SOUTHEAST WITH 3 TO 4
INCHES ELSEWHERE WITH HEAVIEST BAND FROM CARROLL TO NEAR MASON
CITY.

SNOW WILL END SUNDAY NIGHT WITH COLD AIR PERSISTING INTO EARLY
NEXT WEEK. MODELS DO HINT AT SOME MODERATION AFTER MIDWEEK NEXT
WEEK AS UPPER FLOW FLATTENS SOMEWHAT ALLOWING NEAR SURFACE FLOW
FROM THE WEST AS OPPOSED TO THE ARCTIC. PRECIPITATION CHANCES INTO
NEXT WEEK APPEAR RATHER MINIMAL WITH SYSTEMS PASSING TO THE NORTH
OR REMAINING WEST AND SOUTH OF THE AREA BY LATE IN THE FORECAST
CYCLE.

&&

.AVIATION...07/00Z
ISSUED AT 517 PM CST FRI DEC 6 2013

VFR CONDITIONS EXPECTED WITH SOME SCT/BKN MID CLOUDS. NORTHWEST
WINDS THROUGHOUT THE PERIOD AS WELL.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SATURDAY
FOR BUTLER-CALHOUN-CARROLL-CERRO GORDO-CRAWFORD-EMMET-FRANKLIN-
GREENE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-PALO ALTO-
POCAHONTAS-SAC-WEBSTER-WINNEBAGO-WORTH-WRIGHT.

&&

$$

SHORT TERM...AWB
LONG TERM...COGIL
AVIATION...BEERENDS