Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 211739
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1139 AM CST WED JAN 21 2015

.SYNOPSIS...
ISSUED AT 318 AM CST WED JAN 21 2015

LOW PRESSURE OVER NORTHEASTERN IA WILL MOVE TO THE UPPER OH RIVER
VALLEY THIS AFTERNOON. HIGH PRESSURE WILL DOMINATE THE AREA
TONIGHT INTO THE WEEKEND. ANOTHER CLIPPER TYPE SYSTEM WILL MOVE
THROUGH THE UPPER MIDWEST SUNDAY AND PASS TO THE EAST BY MONDAY.

&&

.SHORT TERM /TODAY/...
ISSUED AT 318 AM CST WED JAN 21 2015

LIGHT SNOW CONTINUES TO FALL ACROSS NORTHERN/NORTHEASTERN IOWA.  A
SURFACE LOW CENTERED OVER WATERLOO WILL CONTINUE TO SHIFT SOUTHEAST
ACROSS IOWA AND WILL ACTUALLY EXIT THE STATE BY 15 OR 16Z.  HOWEVER
THE UPPER LEVEL SHORTWAVE IS STILL UPSTREAM AND LIGHT PRECIP WILL BE
POSSIBLE UNTIL THE WAVE PASSES IN THE AFTERNOON.  ANY REMAINING
FORCING IS WEAK AND DISORGANIZED SO I AM NOT LOOKING FOR MUCH BY WAY
OF ACCUMULATION. WE ALSO LOSE OUR DEEPER SATURATION AND ICE
INTRODUCTION PERIODICALLY LATE MORNING AND AFTERNOON SO I WOULD NOT
BE SURPRISED TO SEE PATCHY FREEZING DRIZZLE BEFORE THE UPPER WAVE
FINALLY MOVES EAST.  RADAR SHOWS A COUPLE OF VORT MAXES IN THE FLOW.
ONE IS PUSHING EAST OF THE FORECAST AREA NOW AND THE NEXT ONE
UPSTREAM IS OVER SERN MN. THERE IS SOME CONCERN FOR A BRIEF
PERIOD OF ENHANCEMENT OF SNOW WHEN THIS COMES THROUGH BUT LACK OF
FORCING AND LACK OF DEEPER MOISTURE PRECLUDES ANY CONCERN FOR
THIS.

WIDESPREAD STRATUS SHIELD LEAVES LITTLE HOPE FOR CLEARING TODAY AND
WILL KEEP LOW CLOUDS IN THE FORECAST.  COOLER AIR WILL MOVE INTO THE
STATE THIS AFTERNOON AND TONIGHT BEHIND THE DEPARTING SYSTEM BUT
TEMPS SHOULD STILL BE AT OR ABOVE SEASONAL NORMALS.


.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 318 AM CST WED JAN 21 2015

HIGH PRESSURE AND TRANQUIL WEATHER WILL HOLD THROUGH FRIDAY NIGHT.
THE AIRMASS IS QUITE MILD AND EXPECT TO SEE TEMPS REMAIN ABOVE MOS
VALUES. FRI AND SAT WITH VERY WARM AIR AT H8 PASSING. SOUTHWEST
WINDS WOULD SUGGEST GOING HIGHER THAN CURRENT FORECAST. ONLY
SLIGHT DIFFERENCES IN MODELING FROM YESTERDAYS FORECAST WITH A
SLIGHT SHIFT TO THE NORTHEAST WITH THE BAROCLINIC RIBBON. GIVEN
THE NORTHEAST SHIFT AND THUS WARMER TEMPS...DO NOT EXPECT TO SEE
MUCH IN THE WAY OF SNOW ACCUMULATION FORM THIS SYSTEM IN IOWA.
THAT SETS THE STAGE FOR MILD WEATHER TO CONTINUE INTO NEXT WEEK.
IOWA WILL REMAIN ON THE BOUNDARY BETWEEN THE PACIFIC AND POLAR AIR
WELL INTO NEXT WEEK BEFORE A STRONGER POLAR HIGH DROPS SOUTH LATER
IN THE WEEK.

&&

.AVIATION...21/18Z
ISSUED AT 1138 AM CST WED JAN 21 2015

LARGE STRATOCUMULUS SHIELD WILL AFFECT THE AREA THROUGH THE ENTIRE
TAF PERIOD. -SN SHOWERS AT MCW/ALO WILL GRADUALLY FADE OUT BY THIS
EVENING...BUT IFR CIGS AND BR WILL REMAIN POSSIBLE THROUGH THE
NIGHT ESPECIALLY AT THE NORTHERN TERMINALS. HAVE TAKEN A BEST
GUESS AT TIMING THE TRANSITIONS BETWEEN MVFR/IFR THRESHOLDS IN THE
18Z TAF PACKAGE...BUT ANTICIPATE AMENDMENTS WILL LIKELY BE
NECESSARY.

&&

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

&&

$$

SYNOPSIS...MS JAN 15
SHORT TERM...FAB
LONG TERM...MS JAN 15
AVIATION...LEE


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