Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 292332
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
632 PM CDT MON JUN 29 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 254 PM CDT MON JUN 29 2015

MAIN CHALLENGE TONIGHT WILL BE EXTENT OF CONVECTION THIS EVENING.
SYNOPTIC MODELS SHOWING COLD FRONT ENTERING THE FAR NORTH BY 00Z
WITH FRONT HEADING TO SOUTHEAST IOWA BY 12Z TUESDAY. BEST FORCING
FOCUSED OVER THE EASTERN/NORTHEAST PORTION OF THE FORECAST AREA
THIS EVENING. MESOSCALE MODELS SUPPORT THIS AS WELL WITH HRRR AND
VARIOUS WRF SOLUTIONS SUGGESTING THAT BEST SFC MOISTURE
CONVERGENCE WILL FOCUS OVER NORTHEAST SECTIONS FROM NEAR MASON
CITY SOUTHEAST TOWARD OTTUMWA. CURRENT INSTABILITY REMAINS MODEST
WITH MLCAPES BETWEEN 1500 AND 2000 J/KG OVER THE EAST THOUGH WITH
LACK OF SFC TRIGGER...LITTLE THREAT FOR ANY CONVECTION UNTIL LATE
AFTERNOON AND SHOULD REMAIN QUITE LIMITED...IF AT ALL...UNDER
BOUNDARY GETS CLOSER OR OUTFLOWS FROM STORMS CAN FIRE CONVECTION
DOWNSTREAM. WITH THE BETTER CHANCES FOR CONVECTION OVER THE EAST
THIS EVENING...WILL BE NARROWING POPS/WX OVER THE FORECAST AREA.
GIVEN THE DIURNAL SUPPORT NEEDED TO SUSTAIN CONVECTION...AM
EXPECTING A LESSENING OF COVERAGE AFT 02Z WITH ISOLATED COVERAGE
THROUGH MID TO LATE EVENING. SMOKE FROM SASKATCHEWAN FIRES
IMPACTING SUNSHINE THIS AFTERNOON AND THICKER LAYER OF SMOKE
LIKELY TO CONTINUE OVER IOWA SKIES TONIGHT. THIS SHOULD RESULT IN
A BRILLIANT SUNSET FOR AREAS WITH LESSER CLOUD COVER. LOWS
OVERNIGHT WILL COOL TO THE LOWER TO MID 60S OVER THE REGION.

.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 254 PM CDT MON JUN 29 2015

SOMEWHAT QUIET WEATHER PATTERN SETTING UP OVER CENTRAL IOWA
THROUGHOUT THE WEEK AND INTO THE HOLIDAY WEEKEND. NORTHWEST FLOW
ALOFT CONTINUES TO DOMINATE THE WEATHER PATTERN AND A FEW
SHORTWAVES MOVE INTERMITTENTLY ACROSS THE FORECAST AREA THROUGH
FRIDAY AND BRING SLIGHT TO LOW CHANCE POPS TUESDAY NIGHT INTO
FRIDAY. TIMING AND LOCATION OF SHORTWAVES WAS THE MAIN CONCERN
THROUGH THE EXTENDED PERIOD. OTHER CONCERN WAS TEMPS AND HOW THEY
WILL BE AFFECTED BY THE SMOKE PLUME FROM CANADA.

TUESDAY INTO FRIDAY...FIRST SHORTWAVE IS ANTICIPATED TO CUT ACROSS
WESTERN IOWA LATE TUESDAY NIGHT INTO WEDNESDAY. SURFACE HIGH OVER
THE GREAT LAKES LOOK TO BECOME MORE DOMINANT AND SHOULD HOLD OFF THE
SHORTWAVE TO FURTHER SOUTH AND WEST. PLUS...THE SURFACE HIGH WILL
ADVECT IN DRIER AIR INTO THE STATE THROUGHOUT THE WEEK. TRENDED
TOWARD A DRIER FORECAST OVER CENTRAL TO NORTHEAST PORTIONS OF THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. ANOTHER SHORTWAVE MAKES
A SIMILAR TRACK...MAYBE EVEN SHOVED FURTHER WEST BY THE SURFACE
HIGH...THURSDAY NIGHT INTO FRIDAY. WENT CLOSE TO GUIDANCE FOR HIGH
TEMPS TUESDAY BUT LOW CONFIDENCE IN HOW MUCH THE SMOKE FROM CANADA
WILL AFFECT THE MAX TEMPS...ESPECIALLY SINCE DO NOT KNOW WHEN THE
FIRES WILL CEASE. IF SMOKE IS STILL AROUND ON TUESDAY...THEN LIKELY
NEED TO DROP A DEGREE OR TWO OFF THE CURRENT FORECAST.

SATURDAY INTO MONDAY...SURFACE HIGH CONTINUES TO DOMINATE THE
WEATHER PATTERN ON SATURDAY BEFORE A FAIRLY STRONG SHORTWAVE
ATTEMPTS TO BREAK THROUGH BY SATURDAY NIGHT. HOWEVER...SYSTEM REMAINS
MOISTURE STARVED AND THUS HAVE LOW POPS AND LOW CONFIDENCE WITH
ANY WIDESPREAD PRECIP LATE IN THE WEEKEND.

&&

.AVIATION...30/00Z
ISSUED AT 632 PM CDT MON JUN 29 2015

CHANCES FOR THUNDERSTORMS LOOKING BETTER EAST OF THE AREA...SO
HAVE REMOVED MUCH OF THE MENTION IN ALL TAF SITES. STILL A SMALL
POSSIBILITY IN THE EASTERN TAF SITES...BUT LOOKING QUITE
UNCERTAIN. OTHERWISE STILL EXPECTING MAINLY THIN OVERCAST
CONDITIONS THROUGH THE PERIOD WITH THE SMOKE IN THE HIGHER LEVELS.
WINDS TO BECOME MORE NORTHERLY WITH TIME AND PICK UP A BIT INTO
TUESDAY.

&&

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

&&

$$

SHORT TERM...REV
LONG TERM...PODRAZIK
AVIATION...BEERENDS



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