Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 241114
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
614 AM CDT THU JUL 24 2014

.SYNOPSIS...
ISSUED AT 319 AM CDT THU JUL 24 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE MN ARROWHEAD WAS PROVIDING MOSTLY
CLEAR SKIES AND COOL TEMPERATURES OVER THE REGION EARLY THIS
MORNING. 00Z UPPER AIR ANALYSIS SHOWED THE AREA WAS UNDER A NW
FLOW ALOFT BETWEEN A RIDGE AXIS REACHING FROM THE SOUTHERN ROCKIES
INTO CENTRAL CANADA AND A LOW OVER HUDSON BAY. FURTHER WEST...AN
UPPER LOW WAS DEEPENING JUST OFF THE WA COAST. HEIGHT FALLS OUT
AHEAD OF THIS LOW BACKED THE MODEL DEPICTION OF THE FEATURE PUSHING
EASTWARD...WHICH WOULD FLATTEN THE UPPER RIDGE AND RETURN A
WARMER...AND MORE ACTIVE WEATHER PATTERN INTO THE FORECAST AREA FOR
THE WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CDT THU JUL 24 2014

THE SURFACE HIGH BUILDING SOUTHEAST INTO THE GREAT LAKES REGION WILL
PROVIDE ANOTHER DAY OF PARTLY CLOUDY SKIES...LOW HUMIDITY AND
SEASONABLY MILD TEMPERATURES. THE MAIN FORECAST CHALLENGE IS AN MCS
EXPECTED TO IMPACT THE AREA BEGINNING LATE THIS EVENING.

TODAY...HIGH PRESSURE BECOMES CENTERED OVER SOUTHERN LAKE MI BY LATE
AFTERNOON...KEEPING LIGHT EAST AND THEN SOUTHEAST WINDS OVER THE
AREA. THIS WILL KEEP THE AREA UNDER THE SAME AIR MASS AS YESTERDAY
WITH DEWPOINTS IN THE 50S AND SCATTERED DIURNAL CUMULUS CLOUDS.
BASED ON PERSISTENCE FROM YESTERDAY/S HIGHS PLUS MINOR
WARMING...HAVE GONE NEAR TO ABOVE GUIDANCE WITH HIGHS FROM THE MID
70S OVER NW IL TO THE LOWER 80S CENTRAL AND SOUTHWEST.

TONIGHT...THE FIRST IN A SERIES OF SHORTWAVES TOPPING THE FLATTENING
RIDGE OUT WEST COMBINES WITH STRONG MOISTURE RETURN AND WARMING
ALOFT ON A 40 KT 850 MB JET TO TRIGGER AN MCS OVER NORTHERN IA AND
SOUTHERN MN ROUGHLY BETWEEN 9 PM AND MIDNIGHT. THE GRADUAL EASTWARD
EXPANSION OF THESE FEATURES WILL SUPPORT THIS SYSTEM CONTINUING EAST
AND THEN TRENDING SOUTHEAST ALONG CORFIDI VECTORS INTO THE FORECAST
AREA TOWARD MORNING. HAVE FINE TUNED TIMING AND POPS SOME FOLLOWING
A DECENT MODEL CONSENSUS INDICATING INITIALLY HIGH BASED SHOWERS AND
THUNDERSTORMS REACHING INTO THE FAR NW TOWARD MIDNIGHT...AND HAVE
LIMITED LATE EVENING CHANCE POPS IN THIS AREA. AFTER MIDNIGHT...HAVE
GONE WITH LIKELY TO CATEGORICAL POPS OVER EAST CENTRAL IA WITH
CHANCES ELSEWHERE TOWARD MORNING AS THE SYSTEM DEVELOPS AN OUTFLOW
THAT MAY EXPAND AND TRIGGER ADDITIONAL SUNRISE CONVECTION TO THE
SOUTHEAST. HOWEVER...WITH THE STRONGEST ELEVATED THETAE ADVECTION
AND CONVERGENCE REMAINS MORE STRONGLY FOCUSED OVER N CENTRAL INTO NE
IA IN THE OVERNIGHT PERIOD...THE POTENTIAL FOR HEAVY RAINFALL LOOKS
LOW AND HAVE KEPT QPF IN A WIDESPREAD QUARTER TO HALF INCH RANGE
MAINLY NORTH OF I-80 AND WEST OF HIGHWAY 218 IN EASTERN IA. THE
POTENTIAL FOR SEVERE STORMS WILL ALSO BE LOW DUE TO THE MARGINAL
ELEVATED INSTABILITY. MODELS DO DEVELOPING STRONGER DEEP SHEAR
TOWARD 12Z...WHICH COULD ALLOW A FEW STORMS TO PRODUCE SMALL HAIL
AND GUSTY WINDS OVER EASTERN IA TOWARD SUNRISE. THE LATE ONSET OF RAIN AND
INITIAL DRY AIR MASS AREA SHOULD ALLOW TEMPERATURES TO COOL TO LOWS
FROM THE UPPER 50S EAST TO AROUND 60 WEST.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU JUL 24 2014

FRIDAY AND SATURDAY...MCS FROM SHORT TERM TIME FRAME WILL PERSIST
EARLY FRIDAY THEN MOVE OFF TO THE SOUTHEAST. WHAT THIS SYSTEM
LEAVES IN ITS WAKE WILL DETERMINE WEATHER FRIDAY NIGHT INTO
SATURDAY. A LINGERING BOUNDARY COULD BE A FOCUS FOR ADDITIONAL
THUNDERSTORM ACTIVITY IF THE CAP DOES NOT RESTRAIN IT. THEN
SATURDAY AS THE SURFACE LOW MOVES EAST THE SYNOPTIC BOUNDARY
STALLS IN OR NEAR THE SOUTHERN PART OF THE CWA. WITH THE SAME CAP
CAVEAT...THIS FEATURE COULD FOCUS THUNDERSTORMS SATURDAY AFTERNOON
AND EVENING. GIVEN THE UNCERTAINTY WITH THE LATTER TWO THUNDERSTORM
OPPORTUNITIES...HAVE MAINTAINED GENERALLY CHANCE POPS.

PWS WILL BE HIGH THOUGH NOT LIKELY AS GENEROUS AS DEPICTED IN THE
NAM AND GFS. SO LOCALLY HEAVY RAIN IS A POSSIBILITY. SINCE WE HAVE
BEEN DRY FOR A WHILE...THE SOIL HAS THE CAPACITY TO BUFFER THE
RAIN AND THUS MINIMIZE THE FLASH FLOOD THREAT. WHILE CAPE/SHEAR
ARE SUFFICIENT FOR SEVERE STORMS...THE LACK OF A STRONG FOCUS...A
VERY MOIST ATMOSPHERE...AND THE AFOREMENTIONED CAP ARE LIMITING
FACTORS.

SUNDAY...MODELS HAVE COME INTO AGREEMENT IN SWINGING THE UPPER
LEVEL TROUGH THROUGH THE AREA...THOUGH MOST OF THE UPPER-LEVEL
SUPPORT FOR PRECIP IS TO OUR NORTHEAST. MID-LEVEL LAPSE RATES
DON`T LOOK TOO IMPRESSIVE...BUT HAVE INCLUDED SOME LOW POPS FOR
POSSIBLE POP-UP AFTERNOON SHOWERS.

MONDAY THROUGH WEDNESDAY...SURFACE HIGH PRESSURE AND NORTH TO
NORTHWEST FLOW ALOFT WILL BRING A RETURN OF THE COOLER THAN NORMAL
AND DRY WEATHER WHICH HAS BEEN SO COMMONPLACE THIS SUMMER. THAT
LEADS INTO WEEK TWO.  SEE BELOW FOR DETAILS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 613 AM CDT THU JUL 24 2014

HIGH PRESSURE WILL PROVIDE LIGHT EAST WINDS AND PARTLY CLOUDY
SKIES TODAY THROUGH THIS EVENING. TONIGHT...A COMPLEX OF
THUNDERSTORMS IS EXPECTED TO MOVE INTO EASTERN IOWA AFTER
MIDNIGHT. THE CID TERMINAL WILL HAVE THE GREATEST CHANCE OF BEING
IMPACTED BY THE STORMS AND A TEMPO GROUP HAS BEEN INCLUDED FOR
MVFR CONDITIONS TOWARD MORNING. CONFIDENCE IS LOWER FOR MLI AND
DBQ...WHERE THIS POTENTIAL IS INCLUDED IN PROB30 GROUPS. THERE IS
A LOW PROBABILITY THAT STORMS MAY REACH THE BRL SITE...BUT
CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAF THIS CYCLE.

&&

.CLIMATE...
ISSUED AT 319 AM CDT THU JUL 24 2014

RECORD LOWS FOR TODAY...JULY 24...

MOLINE.........54 IN 1957
CEDAR RAPIDS...50 IN 1927
DUBUQUE........51 IN 2003
BURLINGTON.....51 IN 2003

WEEK 2...
CPCS OUTLOOK GOING INTO THE FIRST WEEK OF AUGUST INDICATES THE
LIKELY CONTINUATION OF COOLER THAN NORMAL TEMPERATURES IN THE AREA.
PROBABILITIES FAVOR NEAR NORMAL RAINFALL. EXCELLENT GRAPHICS
DEPICTING THIS INFORMATION AT THE LOCAL LEVEL ARE AVAILABLE AT
WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/814DAY/INTERACTIVE/INDEX.PHP
ALL IN LOWER CASE.

&&

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

$$

SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...WOLF
AVIATION...SHEETS
CLIMATE...WOLF





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