Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 032340
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
640 PM CDT THU SEP 3 2015

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...
ISSUED AT 326 PM CDT THU SEP 3 2015

LATEST SFC ANALYSIS WAS INDICATING A WEAK FRONT SAGGING SOUTHWARD
ACRS THE EASTERN IA/MN BORDER REGION INTO SOUTHERN WI. SOME MARGINAL
CONVERGENT LLVL FLOW ALONG THIS FEATURE...WITH CURRENTLY MORE
PRONOUNCED CU FIELD ACRS SOUTHWESTERN WI INTO NORTHEASTERN IL. MORE
SUNSHINE AND SOUTHWEST WINDS OF GENERALLY 7-10 MPH PRODUCING AMBIENT
TEMPS ACRS THE CWA IN THE UPPER 80S TO LOWER 90S WITH MORE AREAS AT
LEAST 90 AS OPPOSED TO 80S. THIS COUPLED WITH LOW 70S DPTS MAKING
FOR LOW TO MID 90 HEAT INDEX READINGS WITH A FEW UPPER 90 READINGS.
ALOFT...A LARGE BULGING UPPER RIDGE/HEAT DOME ACRS MUCH OF THE
CENTRAL CONUS. BUT WATER VAPOR IMAGERY AND THIS MORNING/S UPPER AIR
ANALYSIS WERE INDICATING AN EMBEDDED UPPER LOW ACRS NORTHERN
MI...AND A SECONDARY VORT SPOKE SWIRLING SOUTH-SOUTHEASTWARD ACRS
NORTHERN WI.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 326 PM CDT THU SEP 3 2015

TONIGHT...WITH THE SFC FRONT PUSHING INTO THE FAR NORTHERN AND
NORTHEASTERN CWA THIS EVENING AND OVERNIGHT...ALONG WITH THE VORT
SPOKE ROLLING DOWN ACRS SOUTHERN WI THERE WILL BE A CHANCE FRO AT
LEAST AN ISOLATED SHOWER OR STORM INTO THE FAR NORTHERN AND
NORTHEASTERN CWA LATE THIS AFTERNOON AND WELL INTO THE EVENING. IT
CURRENTLY APPEARS A BETTER CHC IN HEART OF THE CURRENT CU FIELD JUST
TO THE NORTH AND EAST OF THE LOCAL AREA...BUT THE EVENING SHIFT WILL
HAVE TO BE ON THE WATCH FOR DEVELOPMENT FURTHER SOUTH AND WEST. WILL
KEEP AND FINE TUNE THE LOW CHC/ISOLATED POPS IN THE NORTH AND
NORTHEAST WITH A LEAN TOWARD THE LATEST RUN HIRES/HRRR-CR/ARW-EAST
WHICH SEEM TO HAVE A HANDLE. IF A FEW SHOWERS/STORMS MANAGE TO
DEVELOP IN OR MAKE IT INTO THE CWA THEY MAY LINGER WELL INTO THE
OVERNIGHT BEFORE DECREASING LATE WITH SUPPORT FROM THE APPROACHING
VORT SPOKE. POST-FRONTAL CLOUD DECK CURRENTLY ACRS NORTHEAST WI WILL
ALSO LOOK TO TRY AND PUSH SOUTHWEST TOWARD THE CWA...BUT WILL BANK
ON MOST OF THEM FALLING SHORT. THEY COULD HOLD TEMPS UP IN THE
NORTHEASTERN CWA HIGHER THAN FCST VALUES. OTHERWISE WILL BE GOING
WITH LOWS SIMILAR TO THE PAST FEW NIGHTS OF MID 60S TO LOWER 70S.
LIGHT LLVL CONVERGENT FLOW AREA IN THE VCNTY OF THE FRONT MAY FOSTER
SOME FOG IN THE NORTHEASTERN CWA LATE TONIGHT...BUT CONFIDENCE NOT
THERE CURRENTLY TO PLACE IN THE GRIDS.

FRIDAY...A DAY SIMILAR TO TODAY WITH LIKE THERMAL PROFILES...
POSSIBLY A BIT WARMER PROFILES THAN TODAY. BUT FCST SOUNDINGS
SUGGEST SOMEWHAT WEAKER MIXING AND THE POSSIBILITY OR MORE CLOUDS
ESPECIALLY IN THE NORTHEASTERN THIRD OF THE CWA....THUS FOR NOW WILL
GO WITH HIGHS SIMILAR TO OR A FEW DEGREES COOLER THAN CURRENT TEMPS
OUT THERE NOW. WITH LINGERING FRONTAL ZONE DRAPED ACRS THE
NORTHEASTERN/EASTERN CWA AND VORT MAX TRAPPED ACRS LK MI INTO LOWER
MI BY BLOCKING UPPER PATTERN...WILL GO WITH LOW CHC/ISOLATED POPS
MAINLY FRI AFTERNOON IN THE FAR EASTERN/NORTHEASTERN CWA WITH A
WATCH FOR A NEED TO EXPAND THEM WESTWARD TOWARD THE MS RVR DEPENDING
ON CAPPING INVERSION AND WESTWARD LIFT IMPACT OF THE WESTERN GRT LKS
WAVE ALOFT.     ..12..

.LONG TERM...(FRIDAY NIGHT THROUGH NEXT THURSDAY)
ISSUED AT 326 PM CDT THU SEP 3 2015

VERY WARM AND HUMID CONDITIONS WILL CONTINUE ACROSS THE AREA FRIDAY
NIGHT THROUGH SATURDAY NIGHT. LOWS WILL GENERALLY BE IN THE 66 TO 71
DEGREE RANGE AND HIGHS WILL BE IN THE 87 TO 92 DEGREE RANGE.

THE CHANCES FOR RAIN ARE NOT VERY GOOD BUT THERE IS A POTENTIAL SOME
FOR DIURNALLY DRIVEN CONVECTION IN THE FAR NORTHEAST AND EAST AREAS
FRIDAY EVENING AND AGAIN SATURDAY AFTERNOON. SATURDAY NIGHT
CURRENTLY LOOKS TO BE DRY.

SUNDAY WILL BE THE LAST DAY OF VERY WARM AND HUMID CONDITIONS. A
COLD FRONT WILL BE SLOWLY MOVING ACROSS IOWA SO CLOUD COVER MAY KEEP
TEMPERATURES IN THE 85 TO 90 DEGREE RANGE. PARTS OF BENTON AND
BUCHANAN COUNTIES MIGHT SEE SOME ISOLATED SHOWERS OR THUNDERSTORMS
BY LATE AFTERNOON.

SUNDAY NIGHT ON...

THE EXTENDED WILL BE MARKED WITH A PATTERN CHANGE WITH A GOOD
POTENTIAL OF BELOW NORMAL TEMPERATURES DEVELOPING. ADDITIONALLY...
RAIN CHANCES WILL BE ON THE INCREASE FOR THE FIRST HALF OF THE WEEK.

LATE SUNDAY NIGHT AND MONDAY THE COLD FRONT MOVES THROUGH THE AREA.
THE OVERALL FORCING DOES WEAKEN WITH TIME...ESPECIALLY ON MONDAY SO
THERE ARE QUESTIONS REGARDING HOW EXTENSIVE THE RAIN CHANCES WILL
ACTUALLY BE. RIGHT NOW THE MODEL CONSENSUS HAS CHANCE TO LIKELY POPS
SUNDAY NIGHT WITH CHANCE POPS ON MONDAY.

THE COLD FRONT WILL THEN STALL OUT EITHER OVER THE AREA OR ACROSS
NORTHERN MISSOURI AND INTO CENTRAL ILLINOIS MONDAY AFTERNOON. THE
FRONT IS THEN EXPECTED TO VACILLATE ACROSS THE AREA TUESDAY THROUGH
WEDNESDAY. CONCEPTUALLY...THE SCENARIO OF AN EAST WEST FRONTAL
BOUNDARY ACROSS THE AREA RAISES THE QUESTION REGARDING HEAVY RAIN
POTENTIAL. INTERNALLY THE MODELS HAVE SOME SUBTLE SIGNALS SUGGESTING
HEAVY RAIN BUT THEY ARE QUITE WEAK. THESE SIGNALS WILL HAVE TO BE
WATCHED OVER THE NEXT 72 HOURS IN ORDER TO SEE IF THEY TREND
STRONGER.

AS A RESULT...THE MODEL CONSENSUS HAS CHANCE POPS MONDAY NIGHT
THROUGH TUESDAY NIGHT. THESE POPS MAY TREND HIGHER OVER THE NEXT
SEVERAL DAYS.

A LARGE COOL CANADIAN HIGH WILL PUSH THE FRONT OUT OF THE AREA
EITHER ON WEDNESDAY OR WEDNESDAY NIGHT. THE MODEL CONSENSUS HAS
SLIGHT CHANCE TO CHANCE POPS ON WEDNESDAY AND SLIGHT CHANCE POPS
WEDNESDAY NIGHT.

THE MODELS ARE INDICATING THE CANADIAN HIGH WILL BE ACROSS THE AREA
ON THURSDAY. AS SUCH THE MODEL CONSENSUS HAS DRY CONDITIONS WITH
COOLER THAN NORMAL TEMPERATURES.     ..08..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 634 PM CDT THU SEP 3 2015

RIDGE OF HIGH PRESSURE ALOFT WILL KEEP VFR CONDITIONS GOING
THROUGH THE TAF PERIOD. MINOR PATCHY FOG POSSIBLE LATE
TONIGHT...BEST CHANCES FOR THICKER/MORE WIDESPREAD FOG IS AT KDBQ
WITH LIGHT E/SE SFC FLOW. DROPPED VSBYS AS LOW AS 3SM AT
KDBQ...BUT COULD BRIEFLY BE LOWER BETWEEN 10-14Z/FRI.
UTTECH

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...08
AVIATION...UTTECH


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