Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 181743
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1243 PM CDT THU SEP 18 2014

.SYNOPSIS...
ISSUED AT 347 AM CDT THU SEP 18 2014

AT 3 AM CDT...PATCHY DENSE FOG HAD DEVELOPED IN RIVER VALLEYS AND
LOW LYING AREAS...REDUCING VISIBILITIES TO A QUARTER MILE OR LESS.
OTHER THAN THE FOG...THE SKY WAS MOSTLY CLEAR ACROSS EASTERN IOWA
AND NORTHWEST ILLINOIS...WITH A CALM OR LIGHT SOUTHEASTERLY WIND.
EARLY MORNING TEMPERATURES RANGED FROM THE MID 40S TO LOWER 50S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT THU SEP 18 2014

QUIET WEATHER WILL CONTINUE THROUGH THE SHORT TERM PERIOD WITH THE
MAIN CONCERN BEING THE FOG THIS MORNING. A CLEAR SKY...AND CALM OR
LIGHT SOUTHEASTERLY WIND HAS ALLOWED SOME DENSE FOG TO DEVELOP. A
CHECK OF AREA WEB-CAMS INDICATES THE IMPACTS ARE LIMITED MAINLY TO
RIVER VALLEYS AND OTHER LOW LYING AREAS. AS THE DENSE FOG IS
SOMEWHAT LIMITED IN AREAL COVERAGE...WILL HOLD OFF ISSUING AN
ADVISORY AND HANDLE WITH A A SPECIAL WEATHER STATEMENT.

SOUTHEAST WINDS WILL PICK UP A BIT TODAY...AND WITH THE INCREASED
LOW LEVEL MIXING...HAVE RAISED MAX TEMPS 1 TO 3 DEGREES FROM
WEDNESDAY`S HIGHS. MOST AREAS SHOULD PEAK IN THE 70 TO 73 DEGREE
RANGE. FOR TONIGHT...SOUTHEAST FLOW SHOULD BE SLIGHTLY
STRONGER...AND THE IMPACT OF ANY FOG IS EXPECTED TO BE LIMITED TO
AVIATION. THERE IS GOOD AGREEMENT AMONG VARIOUS MODELS IN KEEPING
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH WARM AIR ADVECTION TO THE
WEST OF THE FORECAST AREA LATE THURSDAY NIGHT.     RP KINNEY

.LONG TERM...(FRIDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 347 AM CDT THU SEP 18 2014

FRIDAY THROUGH SUNDAY...STILL APPEARS A LOW CHANCE THAT SOME ELEVATED
WARM AIR ADVECTION TYPE SHOWERS/STORMS DRIFT OUT OF CENTRAL IA AND
ACRS AT LEAST INTO THE WESTERN CWA FRI MORNING. THEN THE STORY OF THE
DAY TO BE MOSTLY SUNNY SKIES AND INCREASING SOUTHEASTERLY TO SOUTHERLY
RETURN FLOW TO WEST OF DEPARTING RIDGE AXIS BOOSTING TEMPS INTO
THE MID TO UPPER 70S BY LATE FRI AFTERNOON. MIXING UP INTO BASE OF
H85 MB INVERSION WOULD EVEN ALLOW FOR SOME TEMPS AROUND 80. THEN
THERE LOOKS TO STILL BE THE CHC OF SHOWERS AN STORMS BLEEDING DOWN
INTO THE NORTHERN CWA LATER FRI NIGHT INTO EARLY SAT MORNING OFF
DIGGING TROF IN ACTIVE WESTERLIES ACRS THE UPPER MS RVR VALLEY.
SOUTH WINDS MAINTAINING OVERNIGHT IN WARM SECTOR OF APPROACHING
SFC FRONTAL SYSTEM TO MAKE FOR A MILDER OVERNIGHT THAN WHAT WE
HAVE HAD FOR A WHILE...WITH LOWS NOT DIPPING OUT OF THE 60S IN
MOST OF THE LOCAL AREA. SAT APPEARING TO BE THE MAIN FROPA
DAY...BUT MEDIUM RANGE SOLUTIONS VARYING ON FRONTAL TIMING AND
PRE-FRONTAL INSTABILITY BUILD-UP. THIS TO BE A FACTOR IN NEW STORM
DEVELOPMENT POTENTIAL ALONG THE FRONT. THE 00Z GFS AND NAM ARE
SLOWER AND ALLOW FOR MORE HEATING/CAPE BUILD UP IF SFC DPTS CAN
MAKE IT INTO THE UPPER 60S TO AROUND 70 AND MOST LOCAL AMBIENT
TEMPS IN THE 80S. THESE SOLUTIONS ALONG WITH CURRENTLY INDICATED
SHEAR ALONG THE FRONT WOULD SUGGEST SOME STRONG TO SVR STORMS
POSSIBLE ALONG WITH LOCALLY HEAVY RAIN SAT AFTERNOON INTO EARLY
EVENING. BUT THE STORMS WOULD BE PROGRESSIVE SO TO LIMIT WATER
TROUBLE ISSUES. THE 00Z ECMWF IS MORE FRONTALLY PROGRESSIVE AND
THUS BULK OF RENEWED DIURNAL CONVECTION TO TAKE OFF ALONG AND
EAST/SOUTH OF THE CWA. FOR NOW WILL KEEP HIGH CHC POPS
GOING...WITH A HIGH TEMP BUST POTENTIAL DEPENDING ON CONVECTIVE
DEBRIS AND FRONTAL SPEED. HIGH AMPLITUDE MID LEVEL FLOW PATTERN TO
EVOLVE BY SUNDAY WITH STEEP NORTHWEST FLOW FLOWING DOWN THE UPPER
MIDWEST. WILL ROUND OUT THE WEEKEND ON SUNDAY WITH MAINLY DRY AND
COOLER/LESS HUMID CONDITIONS.

MONDAY THROUGH NEXT WEDNESDAY...DRIER AND COOLER CONDITIONS MON INTO
TUE BEFORE THERMAL MODERATION INTO MID NEXT WEEK AS UPSTREAM RIDGE
MIGRATES ACRS THE MID CONUS. STILL SOME COOL NIGHT APPEAR POSSIBLE
WITH MON NIGHT LOOKING LIKE WIDESPREAD LOWS IN THE UPPER TO MID 40S
AT LEAST. BUT LATEST MODEL TRENDS HAVE BACKED OFF ON A COOLER AIR
MASS DUMP THAT PREVIOUS RUNS SUGGESTED SOME UPPER 30S WOULD HAVE BEEN
POSSIBLE EITHER MON NIGHT OR NEXT TUE NIGHT. BUT WITH ADDITIONAL
MODEL RUN-TO-RUN FLUCTUATIONS EXPECTED AS THEY TRY TO GET A HANDLE ON
MEAN PATTERN PHASING EARLY NEXT WEEK...WILL HAVE TO KEEP THESE
POTENTIAL COOLER CONDITIONS STILL IN MIND FOR EARLY NEXT WEEK. ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU SEP 18 2014

VFR CONDITIONS ARE EXPECTED THROUGH 06Z/19 AS HIGH PRESSURE MOVES
INTO THE GREAT LAKES. AFT 06Z/19 SOME MODELS ARE SUGGESTING THE
DEVELOPMENT OF LIFR/VLIFR CLOUDS/FOG. GIVEN FLOW OFF THE LAKE AND
A NEARBY BOUNDARY...THE 18Z TAFS SHOW A DETERIORATION TO MVFR/IFR
CONDITIONS THROUGH 12Z/19 WITH THE ACKNOWLEDGMENT OF POTENTIAL IFR/LIFR
CONDITIONS.

&&

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

$$

SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...12
AVIATION...08




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