Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 240843
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
343 AM CDT THU APR 24 2014

.SHORT TERM /TODAY/...
ISSUED AT 343 AM CDT THU APR 24 2014

PRIMARY CONCERNS TODAY WILL BE INTERRELATED PRECIP AND TEMP TRENDS
WITH NOT THE GREATEST CONFIDENCE IN EITHER...ESPECIALLY TEMPS. LONG
WAVE TROUGH IS STILL WELL TO THE WEST JUST EXITING THE ROCKIES AND
ASSOCIATED KINEMATIC FORCING SEEMS TO BE THE MAIN MECHANISM DRIVING
CURRENT KS/NE PRECIP BEHIND THE INVERTED TROUGH.  THERMODYNAMIC
FORCING SEEMS TO BE MAINLY RESPONSIBLE FOR IA/MN PRECIP AND LOOKS TO
GRADUALLY BECOME THE DOMINATE FORCING LATER IN THE DAY.  EXPECT THE
NE/KS PRECIP TO WANE AND BE REPLACED BY WEAK CONVECTION NOW
INCREASING SOMEWHAT ALONG THE I35 CORRIDOR AND MOISTURE TRANSPORT
AXIS. LATEST HIGH RES MODELS SEEM TO HAVE A DECENT HANDLE ON THIS
PROGRESSION AS WELL...WHICH EVENTUALLY ENDS UP WITH LINGERING POPS
IN THE EAST 21Z-00Z.  INSTABILITY IS FAIRLY WEAK AT THE MOMENT WITH
MUCAPES JUST A FEW HUNDRED.  MAX AXIS...STILL ONLY AROUND 500
J/KG...IS STILL OFF TO THE WEST HOWEVER SO THERE MAY BE A MINOR
UPTICK IN INTENSITY THROUGH THE MORNING WITH SOME SMALL HAIL
POSSIBLE...STILL BELOW SEVERE LIMITS.  THE ERN THIRD OF THE FORECAST
AREA MAY SEE ANOTHER HALF INCH PLUS OF BENEFICIAL RAINS.

TEMP GUIDANCE IS QUITE VARIED WITH A DECENT SPREAD IN BOTH RAW AND
MOS VALUES. 8F DIFFERENCE IN DSM MOS FOR INSTANCE. SOME
MODELS...ESPECIALLY RECENT RAP RUNS...WERE MORE AGGRESSIVE MIXING
TODAY WHILE OTHERS KEEP MORE LOW LEVEL MOISTURE IN PLACE.  DO NOT
REALLY HAVE A GOOD FEELING WHICH WAY TO LEAN HERE SO FOLLOWED MORE
OF A BLEND...WHICH IS JUST SLIGHTLY LOWER THAN PERSISTENCE.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 343 AM CDT THU APR 24 2014

SYSTEM SHOULD QUICKLY EXIT THE STATE THIS EVENING...WITH SOME
LINGERING LIGHT SHOWERS/ISOLATED THUNDERSTORMS POSSIBLE ACROSS THE
FAR SOUTHEASTERN CWA EARLY IN THE EVENING. OTHERWISE UPPER LEVEL
RIDGING TO BUILD INTO THE CENTRAL US FRIDAY INTO SATURDAY...WITH WAA
AND DRY CONDITIONS EXPECTED. HIGHLY AMPLIFIED LONGWAVE UPPER LEVEL
TROUGH STILL EXPECTED TO DIG INTO THE DESERT SOUTHWEST
SATURDAY...WITH SOUTHWEST FLOW ALOFT DEVELOPING ACROSS THE CENTRAL
US LATE SATURDAY NIGHT INTO SUNDAY. ALL MODELS EJECTING THIS SYSTEM
INTO THE WESTERN HIGH PLAINS BY SUNDAY AND SLOWLY MOVE IT EAST
NORTHEASTWARD INTO EARLY NEXT WEEK. THIS WILL SET UP A WET ACTIVE
PATTERN ACROSS THE REGION/STATE BY LATE SATURDAY NIGHT INTO EARLY
NEXT WEEK.

FINER DETAILS STILL TO BE DETERMINED WITH SOME UNCERTAINTY IN HOW
FAR THE SFC FRONT WILL PUSH NORTHWARD SUNDAY INTO MONDAY. FOR NOW
MODELS JUST BRING THE SFC FRONT INTO EXTREME SOUTHERN IOWA LATE
SUNDAY INTO MONDAY. INSTABILITY INCREASES ACROSS THE AREA WITH
STRONG PUSH OF MOISTURE NORTHWARD FROM THE GULF AND WAA ALOFT SHOULD
SEE DECENT CHANCE FOR THUNDER ACROSS THE ENTIRE CWA. AS SYSTEM
BECOMES MORE WRAPPED UP AND SLOWLY TRANSLATES EAST INTO LATE MONDAY
THROUGH WEDNESDAY...THREAT OF THUNDER DECREASES WITH MORE STRATIFORM
RAIN EXPECTED. AS THE UPPER LEVEL SYSTEM PUSHES EVER SLOW SLOWLY
EASTWARD...REGION SHOULD REMAIN UNDER THE INFLUENCE OF UPPER LEVEL
CYCLONIC FLOW THROUGH MUCH OF NEXT WEEK WITH A WET AND COOLER
PATTERN EXPECTED.

&&

.AVIATION...24/06Z
ISSUED AT 1203 AM CDT THU APR 24 2014

LOW PRESSURE OVER CENTRAL KS WITH COLD FRONT FROM ERN SD THROUGH
THE LOW INTO THE TX PANHANDLE WILL MOVE EAST TO CENTRAL IA BY
EARLY THU AFTERNOON...AND EAST OF THE TAF SITES BY EVENING.
DETERIORATING CONDITIONS TONIGHT AS MOISTURE AND THUNDERSTORMS
INCREASE AHEAD OF THE FRONT. SEVERAL HOURS OF MVFR CIGS AROUND THE
FRONT. CONDITIONS WILL IMPROVE QUICKLY OVER WRN IA THU
AFTERNOON...AND IN THE EAST BY EVENING.

OUTLOOK...WEAK HIGH PRESSURE WILL MOVE OVER THE STATE ON FRIDAY
WITH GOOD VFR CONDITIONS AND LIGHT WINDS. VFR INTO SATURDAY BEFORE
NEXT WEATHER SYSTEM MOVES IN ABOUT SAT NIGHT.


&&

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

&&

$$

SHORT TERM...SMALL
LONG TERM...BEERENDS
AVIATION...MS APR 14



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