Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 290751
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
251 AM CDT SAT AUG 29 2015

.SYNOPSIS...
ISSUED AT 251 AM CDT SAT AUG 29 2015

MONSOON MOISTURE ACROSS THE AREA...ALONG WITH A SURFACE FRONT LED
TO SHOWERS AND EVEN ISOLATED THUNDERSTORMS THIS MORNING. THESE
SHOWERS AND THUNDERSTORMS WERE SLOWLY MOVING EAST ACROSS THE AREA.
RAINFALL TOTALS FROM THIS SYSTEM RANGED FROM 2 TO 3 INCHES ACROSS
FAR NORTHWEST ZONES TO A TRACE SOUTH OF THE QUAD CITIES. THE
SURFACE LOW PRESSURE ASSOCIATED WITH THESE SHOWERS AND
THUNDERSTORMS IS EXPECTED TO LINGER IN THE AREA AND SERVE AS A
FOCUS FOR AFTERNOON SHOWERS TODAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 251 AM CDT SAT AUG 29 2015

MAIN FORECAST CONCERNS FOR THE SHORT TERM FORECAST IS HOW LONG THE
RAIN STICKS AROUND AND THE DEVELOPMENT OF FOG TONIGHT ACROSS THE
AREA. THE HEAVIEST RAIN SHOULD BE DONE SHORTLY AFTER DAYBREAK.
REDEVELOPMENT OF ISOLATED SHOWERS AND EVEN A RUMBLE OF THUNDER ARE
POSSIBLE THIS AFTERNOON.

H5 FORCING IS FORECAST TO MOVE SOUTH OF THE AREA TODAY. THE SFC
LOW ACROSS CENTRAL IA IS FORECAST TO ELONGATE AND FORM INTO AN
INVERTED TROUGH ACROSS THE CWA. RESIDUAL MOISTURE ACROSS THE AREA
WILL LEAD TO SBCAPE FROM 1500 TO 2000 J/KG ACROSS THE AREA. THIS
WOULD BE SUFFICIENT FOR CONVECTION...HOWEVER...CLOUDS WILL LIKELY
LINGER TODAY AND AFFECT DIURNAL HEATING. CONVECTIVE TEMPS WILL BE
HARD TO REACH AND GFS MODEL SOUNDINGS SUGGEST A LOW LEVEL CAP IN
PLACE. THE BEST CHANCE FOR RAIN AND THUNDERSTORM DEVELOPMENT WILL
BE ASSOCIATED WITH SUFFICIENT HEATING AND WEAK CONVERGENCE IN THE
INVERTED TROUGH AXIS. MY GUT TELLS ME THAT DEEP CONVECTION WILL BE
HARD TO COME BY DUE TO THE LOW LEVEL CAP. WILL MOST LIKELY SEE
ISOLATED CONVECTIVE RAIN SHOWERS....ALTHOUGH I CANNOT RULE OUT
THUNDER IN THE MORE VIGOROUS UPDRAFTS. HIRES CAMS SUGGEST THIS AS
WELL.

TONIGHT...WEAKLY CONVERGENT FLOW ALONG WITH RESIDUAL MOISTURE WILL
LEAD TO PATCHY FOG DEVELOPMENT ACROSS THE AREA. OBS TONIGHT WEST
OF THE LOW SUPPORT THIS NOTION AS WELL. THE BEST CHANCES FOR FOG
DEVELOPMENT WILL BE COLLOCATED WITH ANY RAINFALL FROM TODAY.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 251 AM CDT SAT AUG 29 2015

LATE SUMMER HEAT AND DRY OR MOSTLY DRY NEXT WEEK.

LONG TERM FORECAST CONFIDENCE ASSESSMENT...FAIR OR AVERAGE AGAIN
WITH LIMITED SENSIBLE WEATHER ISSUES DUE TO UPPER RIDGING.  TWO MAIN
ISSUES...THE PRIMARY IS HIGH TEMPERATURES MOST DAYS BASED ON LOW
LEVEL THERMAL FIELDS AND PERSISTENCE SUGGEST HIGHS MOST DAYS TO BE
AT THE LOWER END OF GUIDANCE AND DEFINITELY BELOW SURFACE 2 METER
TEMPERATURES AS 850 TEMPS SHOULD BE IN THE 17C TO 19C AREA. THE
SECOND IS THE MOISTURE BL AND WEAK FORCING SUPPORTING MOSTLY PM NON-
SEVERE THUNDERSTORMS AND MAY BE SOME SHOWERS OF A POPCORN AND SPOTTY
NATURE.

OVERVIEW...INITIALIZATION AND VERIFICATION AT 06Z INDICATES MOST
SOLUTIONS ARE TENDING TO BE TOO MOIST AND HOT UPSTREAM OR FROM THE
SOUTH PLAINS.  RUN TO RUN AND FORCING TOOLS SUGGEST A 70/30 MIX OF
THE GEM-NH AND HI-RES ECMWF FORCING IS PREFERRED.

SUNDAY...POSSIBLE EARLY MORNING PATCHY FOG SHOULD DISSIPATE WITH
MOSTLY SUNNY AND WARM CONDITIONS WITH SOUTH WINDS OF 5 TO 10 KTS AT
MOST.   PERSISTENCE AND LOCAL TOOLS SUPPORT HIGHS 80 TO 85 DEGREES.
SUNDAY NIGHT...LIGHT WINDS AND FAIR SKIES SHOULD ALLOW FOR POSSIBLE
PATCHY FOG AGAIN AND BL DECOUPLING ALLOWING FOR LOWS TO BE AT OR
BELOW THE COOLEST GUIDANCE AT MOST LOCATIONS.  WENT WITH 60 TO 65
DEGREES WITH LOTS OF NEAR 60F READINGS IN THE WAPSI AND ROCK RIVER
VALLEYS SUGGESTED.

MONDAY THROUGH FRIDAY...WEAK UPPER RIDGING AND SOUTH WINDS OF 5 TO
10 KTS TO CONTINUE FOR FAIR SKIES AND VERY WARM CONDITIONS AND
SEASONABLY HUMID FOR EARLY SEPTEMBER.  LITTLE CHANGES MADE BEYOND
LOW POPS MID TO LATE WEEK WHICH MAY ALSO BE POSSIBLE EARLY IN THE
WEEK IN THE MOSTLY AFTERNOON AND EVENING HOURS.  HIGHS MID TO UPPER
80S WITH ISOLATED 90 DEGREE READINGS.  THIS WITH MID 60 DEWPOINTS
WILL RESULT IN THE HEAT INDICES RISING INTO THE LOWER 90S FOR A FEW
HOURS SOME LOCATIONS.  MINS SHOULD BE MOSTLY IN THE MIDDLE 60S WITH
RISK OF PATCHY FOG OR GREATER IN DENSITY AND COVERAGE AS WINDS
SHOULD BE LIGHT AND NIGHTS ARE GETTING LONGER.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 749 PM CDT FRI AUG 28 2015

LITTLE CHANGE FOR THE 00Z/29 TAF ISSUANCE. PERIODS OF RAIN WILL
CONTINUE OVERNIGHT...ESPECIALLY AT KCID/KDBQ/KMLI. MVFR CEILINGS
WILL BE COMMON...ALONG WITH IFR/MVFR FOG FAVORED TOWARD DAYBREAK.
THERE IS SOME POTENTIAL FOR SHOWERS TO REDEVELOP SATURDAY
AFTERNOON...MAINLY IMPACTING KBRL/KMLI.


&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...NICHOLS
AVIATION...RP KINNEY



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