000
FXUS63 KDMX 042334
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
534 PM CST WED DEC 4 2013

...UPDATED AVIATION DISCUSSION...

.SHORT TERM /TONIGHT/...
ISSUED AT 340 PM CST WED DEC 4 2013

AREA OF SFC LOW PRESSURE CURRENTLY CENTERED OVER NORTHEAST IOWA INTO
SOUTHEAST MINNESOTA. SYSTEM WILL CONTINUE TO LIFT NORTHEASTWARD INTO
THE LAKE SUPERIOR/SOUTHERN ONTARIO REGION TONIGHT. THE ASSOCIATED
COLD FRONT HAS PUSHED THROUGH MUCH OF THE CWA...AND WILL CONTINUE
TRACKING EASTWARD THROUGH THE REMAINDER OF THE CWA INTO EARLY
EVENING. MUCH COLDER AIR WRAPPING INTO THE STATE BEHIND THE
FRONT...WITH SITES ACROSS WESTERN IOWA ALREADY INTO THE TEENS. SOME
LIGHT PRECIPITATION STILL TO MOVE THROUGH THE EAST
CENTRAL/NORTHEASTERN CWA OVER THE NEXT FEW HOURS...WITH LIGHT
DRIZZLE CHANGING OVER TO LIGHT FREEZING DRIZZLE SHORTLY BEFORE
TAPERING OFF. LITTLE ICE ACCUMULATION EXPECTED...EXCEPT A LIGHT
GLAZING POSSIBLE BEFORE THE PRECIP TAPERS OFF BY EARLY EVENING.

GUSTY NORTHWEST WINDS TO CONTINUE AS THE SFC PRES GRADIENT REMAINS
TIGHTENED AND STRONGER WINDS ALOFT MAKE THEIR WAY TO THE SFC IN
STRONG CAA PATTERN. H85 TEMPS DROP INTO THE MID TEENS BELOW ZERO
CELSIUS BY 12Z...HOWEVER CLOUD COVER EXPECTED TO REMAIN THROUGH THE
NIGHT WHICH WILL HELP TEMPS FROM BOTTOMING OUT TOO MUCH. STILL
THOUGH EXPECT A CHILLY NIGHT WITH LOWS IN THE SINGLE DIGITS ABOVE
ZERO NORTHWEST TO MID TEENS SOUTHEAST.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 340 PM CST WED DEC 4 2013

COLD AIR WILL BE ENTRENCHED ACROSS THE STATE BY THURSDAY MORNING
WITH SURFACE FRONT WELL SOUTH OF IOWA BY DAYBREAK. DECENT SURFACE
PRESSURE GRADIENT WILL REMAIN AS SURFACE LOW CONTINUES TO DEEPEN
AS IT MOVES TOWARD HUDSON BAY. THEREFORE...BRISK NORTHWEST WINDS
WILL BE COMMON ON THURSDAY WITH WIND CHILLS REMAINING NEAR OR
BELOW ZERO FOR MUCH OF THE FORECAST AREA. THESE WIND CHILLS WILL
DROP INTO THURSDAY NIGHT AND WILL BE CLOSE TO IF NOT IN ADVISORY
RANGE ACROSS NORTHERN IOWA BY EARLY FRIDAY MORNING AND WILL
CONTINUE TO MONITOR FOR POSSIBLE HEADLINES. BESIDES THE COLD
AIR...THE REMAINDER OF THE WEATHER WILL BE QUIET WITH A DRY POLAR
AIRMASS IN PLACE.

THE EURO AND NOW THE GFS HAVE COME MORE IN LINE WITH A SYSTEM
PROJECTED TO PASS THROUGH THE FOUR CORNERS REGION THIS WEEKEND AND
MOVE THROUGH THE MIDWEST. A VERY BROAD AREA OF WEAK TO MODERATE
ISENTROPIC LIFT DEVELOPS ACROSS IOWA AND SURROUNDING AREAS ON
SATURDAY NIGHT INTO EARLY MONDAY MORNING. SATURATION WILL OCCUR
FROM WEST TO EAST ON SATURDAY NIGHT WITH MOST LOCATIONS SEEING
SOME SNOW ON SUNDAY INTO SUNDAY NIGHT. A FEW CONSIDERATIONS AS TO
SNOW AMOUNTS WILL NEED TO BE LOOKED AT INCLUDING THE COLD AIR THE
IMPACT ON SNOW RATIOS. IN ADDITION...GFS BUFR SOUNDING AT KDSM
INDICATE ABOUT A 24 HOUR PERIOD OF PRECIPITATION WHERE A LARGE
DEPTH OF THE SOUNDING AND LIFT IS WITHIN THE DENDRITIC LAYER. THIS
CERTAINLY MAY ENHANCE SNOW AMOUNT POTENTIAL AND WILL HAVE TO BE
CLOSELY WATCHED AS SUBSEQUENT FORECASTS. AFTER THIS EVENT...ANOTHER
PUSH OF ARCTIC AIR IS EXPECTED INTO EARLY NEXT WEEK WITH READINGS
LIKELY NEAR OR BELOW ZERO FOR LOWS.

&&

.AVIATION...05/00Z
ISSUED AT 532 PM CST WED DEC 4 2013

IFR TO MVFR CIGS WILL PERSIST THROUGH MUCH OF THE EVENING INTO
THURSDAY MORNING WITH THE STRONG CAA. SHOULD SEE THE CIGS
GRADUALLY LIFT OVERNIGHT WITH SOME DRIER AIR ADVECTING INTO THE
STATE. ALO/MCW MAY SEE -DZ/BR THIS EVENING BUT LOW CONFIDENCE WITH
MVFR VISIBILITY RESTRICTIONS FOR AN EXTENDED TIME FRAME. HAVE
TAFS IMPROVING PAST 12Z THURSDAY TO VFR CONDITIONS.

&&

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

&&

$$

SHORT TERM...BEERENDS
LONG TERM...COGIL
AVIATION...PODRAZIK