Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 270531
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1131 PM CST MON JAN 26 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 341 PM CST MON JAN 26 2015

HIGH PRESSURE RIDGE WILL SHIFT SLOWLY EAST OVERNIGHT AND BE OVER
CENTRAL MINNESOTA AND INTO NW IOWA BY MORNING. OVERNIGHT WINDS WILL
BE OUT OF THE NORTHWEST TO NORTH MUCH OF THE NIGHT. THIS FLOW WILL
EXTEND UP TO NEAR 3-4 KFT AND WILL BE THE STEERING FLOW FOR A BAND
OF STRATUS CLOUDS TO THE NORTH OVER MINNESOTA. THE STRATUS WILL DROP
SOUTH INTO NORTHERN AND CENTRAL IOWA OVERNIGHT AND COMBINED WITH
WINDS 5 TO 8 MPH WILL KEEP TEMPERATURES IN UP OVERNIGHT. CURRENT
DEWPOINTS ARE HIGH AND WELL INTO THE 30S. AS TEMPERATURES
COOL...SOME QUESTION TO THE POTENTIAL FOR FOG FORMATION. STILL WITH
CLOUDS MOVING IN FROM THE NORTH AND PERSISTENT NORTHERLY WINDS...FOG
FORMATION SHOULD BE LIMITED. BEST POTENTIAL WILL BE OVER THE FAR
WEST AS WINDS DIMINISH AS THE RIDGE NEARS FROM THE WEST. DEWPOINTS
ARE EXPECTED TO LOWER OVERNIGHT AS SFC WINDS BECOME MORE NORTHERLY
WITH DEW POINT DEPRESSIONS INCREASING WHICH WILL LIMIT FOG POTENTIAL
AS WELL. LIKELY THE BIGGER HAZARD OVERNIGHT WILL BE FROST FORMATION
ON ROADS WHERE DEWPOINTS REMAIN HIGHER THAN GROUND TEMPERATURES.

.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 341 PM CST MON JAN 26 2015

MODEL RESOLUTION IN THE FURTHER OUT PERIODS (SATURDAY THROUGH
MONDAY) OF THE LONG TERM FORECAST ARE COMING INTO A LITTLE BETTER
AGREEMENT TODAY...ALTHOUGH TIMING ISSUES REMAIN.  THE GFS IS
STARTING TO LOOK MORE LIKE THE EURO AND CANADIAN MODELS NOW WITH
DEVELOP A TROUGH OVER THE REGION INSTEAD OF A HUGE RIDGE.  THAT
MEANS TEMPS WILL BE TRENDING COLDER OVER THE WEEKEND.  BY SUNDAY
MODELS ARE SUGGESTING HIGHS ABOUT 8 TO 10 DEGREES BELOW SEASONAL
NORMALS.  THERE IS A CHANCE FOR SNOW SATURDAY/SATURDAY NIGHT WITH
THE PASSAGE OF A COLD FRONT BUT AGAIN TIMING ISSUES REMAIN WITH THE
CANADIAN MUCH FASTER AND THE GFS MUCH WETTER. ALONG WITH THE COLD
AND SNOW POTENTIAL...SATURDAY NIGHT AND SUNDAY LOOK BREEZY AS WELL.
WINTER RETURNS NEXT WEEKEND.

GOING BACK TO TOMORROW (TUESDAY) SOUNDINGS SHOW A WARM NOSE OFF THE
SURFACE WHICH IS MORE PRONOUNCED ACROSS THE SOUTH BUT WINDS WILL BE
NORTHERLY AND WIND SPEEDS IN THE LOWEST GATES ARE QUITE LIGHT.  AS A
SURFACE LOW MOVES FROM THE PLAINS INTO THE UPPER MIDWEST...SURFACE
WINDS WILL SHIFT AROUND TO THE SOUTHEAST BUT STILL REMAIN LIGHT SO
IT DOES NOT APPEAR THAT THERE WILL BE MUCH MIXING. COUNTERING THAT
WILL BE A LOT OF SUN SO WHILE WE WILL NOT BE AS WARM AS
TODAY...TEMPS SHOULD STILL REACH THE MID 30S NORTHEAST TO LOWER 50S
SOUTHWEST.

DEEPER MIXING AND A LITTLE STRONGER FLOW WILL OCCUR TUESDAY NIGHT
AND WEDNESDAY AND THIS WILL BE OUR WARMEST PERIOD.  EXPECTED CLOUD
COVER AHEAD OF AN APPROACHING STILL MAKES ME A LITTLE CAUTIOUS TO
BOOST TEMPS TOO MUCH ON WEDNESDAY...ESPECIALLY SINCE THE SURFACE LOW
SHIFTS INTO THE AREA DURING THE AFTERNOON AND WINDS DIMINISH/SHIFT
BY LATE IN THE DAY BUT I AM COMFORTABLE WITH CURRENT FORECASTS SINCE
THE WARM ADVECTION WILL BE STRONG.  EXCEPT FOR THE CANADIAN...ALL
MODELS ARE SIMILAR IN THE TIMING OF THE SHORTWAVE BUT IF THE
SHORTWAVE IS SLOWER OR CLOUD COVER IS NOT EXTENSIVE THEN WE WILL BE
TOO COOL FOR WEDNESDAY. STILL GOING DRY WEDNESDAY WITH JUST SOME
INCREASING CLOUDS THROUGH THE DAY WHICH COULD HAMPER HIGHS.

WHILE MOISTURE WITH THE WEDNESDAY SYSTEM IS WOEFULLY LACKING...IT
SHOULD IMPROVE WEDNESDAY NIGHT...AT LEAST IN THE LOW LEVELS.  PRECIP
WILL BE POSSIBLE ALONG AND WITH THE PASSAGE OF A COLD FRONT AND A
SECOND SHORT WAVE WEDNESDAY NIGHT BUT THERE IS NO ICE INTRODUCTION
AND FRANKLY ABOVE 850MB THERE ISN`T MUCH MOISTURE AT ALL AND
NEGLIGIBLE FORCING.  ALL THAT I SEE WEDNESDAY NIGHT INTO THURSDAY
MORNING IS A TRANSITION FROM MAY SOME RAIN OR MORE LIKELY DRIZZLE TO
FREEZING DRIZZLE OVERNIGHT INTO EARLY THURSDAY MORNING.  THE
REMAINDER OF THURSDAY INTO FRIDAY WILL BE COLD BUT DRY WITH COLD
AIR CONTINUING TO FUNNEL INTO THE REGION THROUGH THE WEEKEND.

&&

.AVIATION...27/06Z
ISSUED AT 1131 PM CST MON JAN 26 2015

PRIMARY CONCERN REMAINS PROGRESSION OF MVFR/VFR STRATUS THAT
EXTENDS ALONG AND NE OF KEST-KDSM-KTVK LINE AT 06Z WITH PATCH OF
CLEAR SKIES OVER ERN IA FROM KALO-KOTM. MORE WIDESPREAD LOWER CIGS
THEN EXTEND ALL THE WAY BACK INTO MN...WI AND IL IN BROAD
CYCLONIC FLOW. NONE OF THE MODELS SEEM TO HAVE A GREAT HANDLE
ON CURRENT CONDITIONS ACROSS IA...BUT ALL MODELS SEEM TO SLIDE
THE STRATUS SLOWLY SOUTH AND WEST INTO TUE MORNING. THERE IS HIGH
CONFIDENCE THAT AT LEAST PATCHY MVFR CIGS WILL OOZE SW THROUGH IA...BUT
DURATION CONFIDENCE IS LOW. HAVE LEFT ENDING TIME AT 16Z UNTIL
EXIT TRENDS BECOME MORE CLEAR. RAP AND NAM SUGGEST IN SIMILAR
LOCATIONS WILL INTO TUE...WHILE HIGH RES NMM/ARW MODELS ARE MORE
OPTIMISTIC.

&&

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

&&

$$

SHORT TERM...DONAVON
LONG TERM...FAB
AVIATION...SMALL



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