Area Forecast Discussion
Issued by NWS Des Moines, IA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDMX 010443
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1143 PM CDT SAT APR 30 2016

.SHORT TERM.../TONIGHT/
ISSUED AT 353 PM CDT SAT APR 30 2016

AREA OF SHOWERS THAT HAS MOVED THROUGH THE CWA TODAY IS EXPECTED TO
PUSH OUT OF THE NORTHERN CWA BY 00Z. WAA CONTINUES ALOFT TONIGHT AS
THE SFC LOW OVER CENTRAL MO WILL SLOWLY LIFT NORTHEAST INTO NE MO
THROUGH 12Z SUNDAY. WEAK THETA-E ADVECTION IN PLACE OVERNIGHT AS
WELL...WITH SATURATION MAINTAINED IN THE LOWER LEVELS. THIS SHOULD
ALLOW FOR THE STRATUS TO STICK AROUND THROUGH THE NIGHT WITH
POSSIBLY A FEW BREAKS THIS EVENING IN THE FAR SOUTH.
OTHERWISE...DEEPER SATURATION EXPECTED TOWARD LATE TONIGHT.
THEREFORE COULD STILL SEE SOME SCATTERED SHOWERS THIS EVENING...OR
PATCHY DRIZZLE. EXPECT TO SEE INCREASING COVERAGE IN SHOWERS LATE
TONIGHT WITH THE STRONGER LIFT AND DEEPER SATURATION...THEREFORE
INCREASED POPS THROUGH THE LATE NIGHT HOURS. TEMPERATURES TO STAY
FAIRLY STEADY IN THE 40S TO AROUND 50 OVERNIGHT WITH THE
WAA...CLOUDY CONDITIONS AND PRECIP.

.LONG TERM.../SUNDAY THROUGH SATURDAY/
ISSUED AT 353 PM CDT SAT APR 30 2016

MAIN CONCERN WILL BE INITIAL PRECIP TRENDS BEFORE PATTERN BECOMES
MORE AMPLIFIED...STAGNANT AND DRIER. AT ONSET CURRENT SYSTEM WILL
STILL BE LINGERING ACROSS IA. CURRENT KS/NE PV ANOMALY WILL BE ON
THE MOVE BY TOMORROW MORNING ACROSS IA/MO BORDER BEFORE EXITING
INTO IL BY 00Z. THIS WILL DISPLACE THE MID LEVEL AND LOWER
THERMODYNAMIC FORCING SOMEWHAT INITIALLY IN THE MORNING WITH THE
MID LEVEL FORCING FARTHER SOUTH INTO THE DRIER AIR...BUT THE
LINGERING DEFORMATION/BAROCLINIC ZONE WILL STILL BE SUFFICIENT TO
PRODUCE MORE LIGHT RAIN IN THE MORNING AND THE INTENSITY MAY EVEN
PICK UP AGAIN WHEN THE DEEPER FORCING PHASES AGAIN...WHICH IS
NOTED IN THE HI RES SIMULATED REFLECTIVITY. THUS HAVE HIT POPS AND
CLOUDS LONGER INTO SUN THAN PREVIOUSLY DEPICTED. PRECIP MAY JUST
LINGER EAST DURING THE EARLY EVENING TOO AS DEEP MOISTURE
EXITS. WITH LIGHT WINDS AND SOME CLEARING...MAY ALSO SEE SOME FOG
DEVELOP SUN NIGHT.

DRYING TREND WILL THEN CERTAINLY START INTO THE NEXT WORK WEEK...BUT
THERE ARE STILL SOME TOKEN PRECIP CHANCES MONDAY. MANITOBA SHORT
WAVE WILL DROP INTO THE GREAT LAKES TROUGH...BUT THE ECMWF AND GFS
HAVE DIFFERENT DEPICTIONS OF ITS PROGRESSION.  THE GFS FADES IT OUT
SOMEWHAT WHILE THE ECMWF SWINGS IT THROUGH THE MO VALLEY.
SOUNDINGS SUGGEST SOME WEAK CONVECTION IS POSSIBLE...AND THE ECMWF
HAS A MORE SW TRACK BRUSHING SWRN IA WITH WEAK LARGER SCALE
FORCING...SO HAVE SW-NE ORIENTED SLIGHT CHANCES. AFTER THIS TIME
FULL SCALE BLOCKING HIGH AMPLITUDE FLOW SETS IN WITH IA STAYING
IN WEAKENING NWLY FLOW AS UPPER RIDGE LEVEL AXIS STAYS TO THE
WEST. NEXT PRECIP CHANCES DO NOT COME UNTIL LATE...DAY 7 AS WARM
ADVECTION ZONE FINALLY OOZES EASTWARD...BUT CONFIDENCE IS NOT
HIGH. SURFACE FLOW WILL REMAIN WEAK THROUGH THE EXTENDED SO TEMPS
SHOULD REMAIN QUITE SEASONAL WITH NO EXTREME WARMING.

&&

.AVIATION.../FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT/
ISSUED AT 1143 PM CDT SAT APR 30 2016

LOW CLOUDS AND LIGHT SHOWERS WILL PERSIST INTO SUNDAY
AFTERNOON...WITH ASSOCIATED IFR OR LOW MVFR VSBYS/CIGS ESPECIALLY
AT DSM/OTM. THERE SHOULD BE STEADY IMPROVEMENT DURING THE
AFTERNOON AS THE SHOWERS GRADUALLY CLEAR OUT...HOWEVER TOMORROW
NIGHT AS WINDS BECOME LIGHT THERE IS SOME QUESTION AS TO HOW MUCH
FOG/STRATUS MAY REDEVELOP OVER THE AREA AFTER SUNSET. THIS WILL BE
FURTHER ASSESSED FOR SUBSEQUENT TAF ISSUANCES.

&&

.HYDROLOGY...
ISSUED AT 353 PM CDT SAT APR 30 2016

LATEST RIVER FORECASTS SUGGEST ESTHERVILLE /DES MOINES RIVER/ AND
PERRY /RACCOON/ RIVER MAY EXCEED FLOOD STAGE IN THE COMING DAYS BUT
THOSE WERE BASED ON QPF RATHER THAN OBSERVED RAINFALL...ESPECIALLY
FOR ESTHERVILLE...SO OPTED FOR HYDROLOGIC OUTLOOKS EARLIER THIS
MORNING RATHER THAN FLOOD WARNINGS. FLOOD WARNINGS MAY BE ISSUED
THIS EVENING OR INTO SUN MORNING HOWEVER ONCE OBSERVED AMOUNTS
ARE INGESTED AND CONFIDENCE INCREASES IN RESPONSE TRENDS. OTHER
LOCATIONS IN THE DES MOINES AND RACCOON BASINS MAY APPROACH FLOOD
STAGE AS WELL.

&&

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

&&

$$

SHORT TERM...BEERENDS
LONG TERM...SMALL
AVIATION...LEE
HYDROLOGY...SMALL


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.