Area Forecast Discussion
Issued by NWS Des Moines, IA

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 032311
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
611 PM CDT FRI JUL 3 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 353 PM CDT FRI JUL 3 2015

SURFACE HIGH PRESSURE ACROSS IOWA WILL CONTINUE TO DOMINATE WEATHER
THROUGH THE OVERNIGHT...WITH MAIN CONCERN BECOMING OVERNIGHT LOW
TEMPERATURES. GIVEN AMOUNT OF DRY AIR AND LIGHT WINDS OVERNIGHT
EXPECT TEMPERATURES TO ONCE AGAIN COOL WELL OVERNIGHT.
HOWEVER...GIVEN WARMER TEMPERATURES TODAY AND WAA BEGINNING TO PUSH
INTO THE NORTH HAVE KEPT TEMPERATURES UP A LITTLE. IN
ADDITION...SMOKE FROM NORTHERN WILD FIRES MAY PUSH INTO IOWA
OVERNIGHT...WHICH COULD AID IN KEEPING TEMPERATURES UP SLIGHTLY. SAW
SOME ARES OF FOG THIS MORNING IN THE WEST AND WITH LIGHT WINDS MAY
BE POSSIBLE AGAIN LATE IN THE PERIOD...BUT GIVEN DRY CONDITIONS HAVE
LEFT MENTION OUT FOR THE EARLY MORNING.

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 353 PM CDT FRI JUL 3 2015

MAIN CONCERN THROUGH THE PERIOD WILL BE CONVECTION SUN NIGHT INTO
MON NIGHT. PROGRESSIVE PATTERN WILL PUSH OUT CURRENT OH VALLEY
TROUGH WITH MATURING BROAD CANADIAN TROUGH DRIVING OUR SENSIBLE
WEATHER INTO EARLY NEXT WEEK. INITIAL STORY WILL LIKELY BE INFLUENCES
FROM CANADIAN FIRE SMOKE FOR THE FOURTH HOWEVER. VISIBLE
SATELLITE IMAGERY NICELY SHOWS THIS SMOKE UPSTREAM ACROSS THE
DAKOTAS AND MN WITH RESTRICTIONS DOWN TO SEVERAL MILES TIMES AT
TIMES. DO NOT FEEL CONDITIONS WILL BE THAT POOR TOMORROW...BUT
NOAA AIR QUALITY MODELS DO INDICATE VERTICALLY INTEGRATED SMOKE
CONCENTRATIONS INCREASE SAT. THUS HAVE KEPT TEMPS BELOW MOS
GUIDANCE WHICH IS LIKELY TOO HIGH DUE TO SMOKE AND CLIMO
INFLUENCES. SHORT WAVE RIDGE PASSAGE WILL LIKELY PUSH SMOKE
EASTWARD BY SUN HOWEVER. RELATIVELY MOIST GROUND SHOULD STILL
KEEP TEMPS GETTING TO GUIDANCE HOWEVER SO HAVE CONTINUED TO GO
JUST BELOW THOSE VALUES. RECENT BIASES HAVE BEEN ON THE WARM SIDE
TOO.

PRECIP CHANCES WILL INCREASE NW-SE LATE SUN NIGHT THROUGH MON NIGHT
HOWEVER. LOBE OF DEEP FORCING ASSOCIATED WITH CANADIAN LONG WAVE
TROUGH AND TRAILING FRONTAL BOUNDARY WILL DROP INTO THE SIOUXLAND
AREA SUN NIGHT.  PEAK HEATING GENESIS WILL LIKELY BE WELL REMOVED
FROM OUR FORECAST AREA...BUT THE MAGNITUDE OF THE SYNOPTIC FORCING
IN AN AIRMASS WITH INCREASING INSTABILITY WILL LIKELY KEEP THE MCS
GOING THROUGH THE NIGHT. EXPECT RE-DEVELOPMENT DURING PEAK HEATING
MON WITH FRONT PUSHING THROUGH FORECAST AREA DURING THE AFTERNOON.
ALTHOUGH CONVECTIVE DEBRIS MAY LIMIT THINGS SOMEWHAT...BOTH GFS AND
NAM BUFR SOUNDINGS SHOW UNCAPPED MLCAPES RANGING FROM 1800-4000 J/KG
IN THE WARM SECTOR. HIGHER NAM VALUES ARE LIKELY
OVERDONE...DRIVEN BY MID 70 DEWPOINTS...BUT EVEN THE LESS
AGGRESSIVE GFS WOULD SUGGEST UNCAPPED DEVELOPMENT. NEITHER MODEL
SHOWS MUCH IN THE WAY OF DEEP SHEAR HOWEVER WITH VALUES 30KTS OR
LESS IN UNIDIRECTIONAL PROFILES. THUS EXPECT SEVERE POTENTIAL TO
BE LOW. LOCALLY HEAVY RAINS MAY BE MORE OF A CONCERN WITH NAEFS
SPECIFIC HUMIDITIES AND PWATS WELL THROUGH THE 90TH PERCENTILE AND
PUSHING EXTREMES AT TIMES. DETERMINISTIC MODELS ALSO DEPICT WARM
CLOUD DEPTHS OVER 13.5K FT. SYSTEM SHOULD BE TRANSIENT ENOUGH TO
PRECLUDE WIDESPREAD HEAVY RAINS...BUT WILL HAVE TO MONITOR FLASH
FLOODING POTENTIAL FOR ISOLATED AREAS. PRECIP MAY LINGER SOUTHEAST
INTO THE NIGHT BUT EXIT BY TUESDAY.

NEXT PRECIP CHANCES WILL BE INTO DAYS 6 AND 7 AS WEAK SHORT WAVES
DRIFT THROUGH WEAK FLOW.  POPS ARE LOW AT THIS POINT AS DETAILS
DIFFICULT TO COME BY.  ECMWF IS MORE AGGRESSIVE WITH MS VALLEY
TROUGH DRIVING BAROCLINIC ZONE TO OUR SOUTH...WHILE GFS IS WEAKER
RESULTING IN FRONTAL ZONE FARTHER NORTH AND POSSIBLY GETTING
CONVECTION AS FAR NORTH AS IA.

&&

.AVIATION...04/00Z
ISSUED AT 611 PM CDT FRI JUL 3 2015

PREDOMINANT VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD.
POSSIBLE PATCHY MVFR FOG LATE TONIGHT. ANY VSBY REDUCTIONS
ASSOCIATED WITH SMOKE ARE EXPECTED TO REMAIN TO THE NORTH OF IOWA.

&&

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

$$

SHORT TERM...AWB
LONG TERM...SMALL
AVIATION...DONAVON



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