621 
FXUS63 KDMX 170455
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1155 PM CDT SUN JUN 16 2013

...UPDATED AVIATION DISCUSSION...

.SHORT TERM.../TONIGHT /...
ISSUED AT 258 PM CDT SUN JUN 16 2013
CONCERN WILL ONCE AGAIN BE PRECIP TRENDS...ALTHOUGH NOTHING AS 
SIGNIFICANT AS THE PAST SEVERAL DAYS. CURRENT LARGE SCALE
SITUATION HAS SUBTLE JET AND ASSOCIATED WEAK SHORT WAVES FROM
SRN CANADA INTO THE FAR NRN PLAINS...WITH ANOTHER WEAK SHORT WAVE
MOVING FROM WY INTO SD. WIDELY SCATTERED SURFACE BASED CONVECTION
HAS DEVELOPED OVER NRN NE AND SD IN LOW CINH AREAS AHEAD OF THIS
FORCING. THIS ROUND OF CONVECTION WILL LIKELY DISSIPATE WITH LOSS
OF HEATING AS IT MOVES EWD INTO MUCH DRIER AND MORE STABLE
AIRMASS.

SITUATION LATER TONIGHT REMAINS IN QUESTION HOWEVER.  JET SEGMENT 
BEGINS TO MATURE SOMEWHAT OVER THE SRN GREAT LAKES WITH IA IN RIGHT 
ENTRANCE REGION...AND QG FORCING ASSOCIATED WITH WY/SD WAVE 
EVENTUALLY DRIFTS ACROSS THE STATE AS WELL. THIS IS ALSO
COINCIDENT WITH WEAK ISENT LIFT NOTED NORTH ALONG 300/305K
SURFACES. NAM/RAP ALSO SHOW ELEVATED INSTABILITY AND CINH AT LEAST
SLIGHTLY INCREASING AND DECREASING RESPECTIVELY SO THERE IS SOME
POTENTIAL FOR WEAK ELEVATED CONVECTION EARLY MON MORNING.
SOUNDINGS REMAIN QUITE DRY OUTSIDE OF NARROW MOISTURE RIBBON JUST
ABOVE 3KM HOWEVER SO WILL LEAVE FORECAST DRY FOR THE MOMENT BUT AT
LEAST VIRGA IS POSSIBLE. VARIOUS 12Z WRF RUNS ALSO SHOW LITTLE TO
NO PRECIP THROUGH THE VALID PERIOD. TRENDS WILL HAVE TO BE
MONITORED LATER THIS EVENING HOWEVER. HAVE ALSO ADDED PATCHY FOG
WORDING FAR SOUTH LATE WHERE WINDS WILL REMAIN LIGHT AND 60S
DEWPOINTS HAVE LINGERED.

.LONG TERM.../MONDAY THROUGH SUNDAY/...
ISSUED AT 258 PM CDT SUN JUN 16 2013

FLAT NORTHWEST UPPER FLOW IS FORECAST MONDAY MORNING ACROSS THE
NORTHERN CONUS WITH SHORTWAVE TROUGHS EMBEDDED IN THE FLOW. BASED
ON THE 12Z MODEL GUIDANCE...EXPECT TWO SHORTWAVE TROUGHS TO MOVE
THROUGH THE IMMEDIATE VICINITY MONDAY AND TUESDAY. AT THE
SURFACE...THE OVERALL THEME IS FOR A COOL HIGH PRESSURE SYSTEM TO
PUSH SOUTHEAST INTO THE GREAT LAKES BY TUESDAY AFTERNOON. THERE
SHOULD BE A WEAK FRONTAL PASSAGE MONDAY AFTERNOON ACROSS CENTRAL
IOWA ASSOCIATED WITH ONE OF SHORTWAVES. THE FRONT SHOULD MARK THE
LEADING EDGE OF THE COOLER AIR ASSOCIATED WITH THE SURFACE HIGH.
THE 12Z NAM IS HAS THE GREATEST AMOUNT OF LOW-LEVEL MOISTURE AND
SURFACE BASED INSTABILITY MONDAY AFTERNOON ALONG AND SOUTHEAST OF
THE WEAK BOUNDARY. HOWEVER...THE 12Z GFS ALSO HAS AN UNCAPPED
AIRMASS OVER CENTRAL IOWA MONDAY AFTERNOON. ALTHOUGH THE LARGE
SCALE FORCING APPEARS WEEK...THERE MAY BE ENOUGH CONVERGENCE TO
INITIATE SCATTERED SURFACE BASED STORMS AHEAD OF THE BOUNDARY
MONDAY AFTERNOON. WILL FORECAST MODEST POPS FOR THIS SCENARIO.
TUESDAY AND WEDNESDAY LOOK DRY WITH MORE STABLE AIR IN THE AREA AS
THE SURFACE HIGH MOVES PAST.

LOOKING AHEAD BEYOND THE MIDDLE THE WEEK...AN UPPER TROUGH IS
FORECAST TO MOVE ONSHORE IN THE PACIFIC NORTHWEST WITH RIDGING
ALOFT DOWNSTREAM OVER THE PLAINS. CENTRAL IOWA WILL LIKELY BE
ON THE NORTH EDGE OF THE UPPER LEVEL RIDGE BY NEXT WEEKEND WITH A
SURFACE BOUNDARY IN THE VICINITY. WARM MID-LEVEL TEMPS SHOULD HELP
CAP CONVECTION...BUT IA APPEARS TO CLOSE TO THE SOUTHERN EDGE OF
THE WESTERLIES OR THE NORTHERN EDGE OF THE CAP TO INHIBIT STORMS.
WILL FORECAST WARMER TEMPERATURES IN GENERAL AND POPS...WHICH WILL
TEND TO BE HIGHER AT NIGHT.

&&

.AVIATION...17/06Z
ISSUED AT 1150 PM CDT SUN JUN 16 2013

HIGH PRESSURE WILL PROVIDE VFR CONDITIONS THROUGH THE ENTIRE TAF
PERIOD. MAY SEE SOME MVFR FOG DEVELOP AT OTM PAST 09Z AND POSSIBLY
SHORT LIVED IFR...BUT LOW CONFIDENCE WITH MENTION ATTM. 

&&

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

&&

$$

SHORT TERM...SMALL
LONG TERM...JOHNSON
AVIATION...PODRAZIK