Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 150043
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
643 PM CST SUN DEC 14 2014

.UPDATE...
ISSUED AT 623 PM CST SUN DEC 14 2014

UPDATE TO EXPAND DENSE FOG ADVISORY SOUTH THROUGH THE QUAD CITIES
AREA INTO WESTERN ILLINOIS. RECENT OB TRENDS AND SPOTTER REPORTS
SUPPORT MORE WIDESPREAD FOG DEVELOPMENT TONIGHT...MAINLY OVER THE
NORTHEAST HALF OF THE FORECAST AREA WHERE TEMP/DEWPOINT SPREADS
ARE LOWER AND THE LOW LEVEL FLOW IS MORE STAGNANT. VISIBILITIES
EXPECTED TO IMPROVE FROM SOUTH TO NORTH BETWEEN 5 AM AND 8 AM AS
THE RAIN ARRIVES.

&&

.SYNOPSIS...
ISSUED AT 251 PM CST SUN DEC 14 2014

OUR SOUNDING FROM 12Z SHOWS A WARM SUNNY DAY ABOVE 800MB...WHILE
UNDER THAT INVERSION...EXTENSIVE LOW CLOUDS AND FOG ARE TRAPPED NEAR
THROUGH THE SURFACE. THROUGH 2 PM...ONLY THE FAR SOUTH HAS MIXED
INTO THE WARM AIR...AS KEOKUK IS 61 AND PARTLY CLOUDY. THE REST OF
THE CWA REMAINS TIED TO THE DEWPOINT...WITH UPPER 40S NORTHEAST TO
MID TO UPPER 50S WEST/SOUTHWEST AT 2 PM. WE WILL CONTINUE TO WARM
SLIGHTLY THROUGH THE VERY EARLY EVENING...WITH MOISTURE ADVECTION
BEING THE DRIVER.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 251 PM CST SUN DEC 14 2014

FOG WILL PLAGUE THE NORTH ANOTHER NIGHT...AS WINDS BECOME
SOUTHEASTERLY THIS EVENING...THE CONVERGENCE AT LOW LEVELS SHOULD
ONCE AGAIN SUPPORT DENSE FOG IN THE NORTHERN COUNTIES. A DENSE FOG
ADVISORY HAS ALREADY BEEN ISSUED FOR THIS THREAT THROUGH
TONIGHT...THOUGH SOME IMPROVEMENT THROUGH SUNSET IN THOSE LOCATIONS
IS STILL LIKELY.

FOG IS POSSIBLE IN ALL LOCATIONS OVERNIGHT...BUT IS MOST LIKELY IN
THE NORTH WHERE THE CONVERGENCE IS MORE NOTABLE. OTHERWISE...THE
DEEP MOISTURE PLUME AND UPPER FORCING WILL ARRIVE IN THE WEST AFTER
MIDNIGHT...LIKELY AROUND 3 AM. THE RAIN SHIELD SHOULD BE COMPLETELY
STRATIFIED OUT...AND BEGINNING TO WEAKEN AS IT APPROACHES SOUTHEAST
IOWA LATE TONIGHT...AND I SEE LITTLE THREAT OF CONVECTION DUE TO
THIS. MONDAY MORNING...THE DEEP MOISTURE AND WEAKENING DYNAMICS OF
THE CLOSED SYSTEM WILL PROGRESS THROUGH. THE NAM/GFS/ECMWF ALL SHOW
A WEAKENING FORCING SITUATION...AND OFFER LITTLE CONVECTIVE THREAT.
THUS...RAINS DURING THE MORNING SHOULD BE UNDER 0.30 IN ALL
LOCATIONS. RAINFALL OVERNIGHT WILL BE MAINLY IN THE SOUTHWESTERN
COUNTIES THROUGH 6 AM...AND AMOUNTS OF 1 TO 2 TENTHS ARE POSSIBLE
THERE.

I HAVE RETAINED SOME THREAT FOR A RUMBLE OF EMBEDDED THUNDER FOR
MONDAY AFTERNOON. AT THIS TIME...THE UPPER LOW WILL BEGIN MOVING
THROUGH EASTERN IOWA. WHILE LAPSE RATES ARE NOT OVERLY STEEP...THE
AIR ALOFT IS SOMEWHAT COOLER AND DRIER THAN MONDAY MORNING...AND
SOME SHALLOW CONVECTION IS POSSIBLE.  MORE SCATTERED AMOUNTS OF 1 TO
2 TENTHS ARE EXPECTED...BUT WITH SEVERAL HOURS OF THIS SCATTERED
POTENTIAL...LIKELY COVERAGE IS STILL WARRANTED.

TEMPERATURES WILL BE RATHER FLAT OVERNIGHT...WITH DEWPOINTS IN THE
UPPER 40S TO LOWER 50S...WE WONT FALL MUCH.  THIS MILD START WILL
HELP ALLOW FOR HIGHS ON MONDAY TO REACH THE LOWER 50S CENTRAL AND
NORTHEAST TO MID 50S SOUTHWEST.
ERVIN

.LONG TERM...(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 251 PM CST SUN DEC 14 2014

MONDAY NIGHT AND TUESDAY...GOOD AGREEMENT WITH LATEST 12Z RUNS IN
SUGGESTING NEARLY VERTICALLY STACKED CYCLONE ROLLING FROM THE
CENTRAL IA/MO BORDER REGION TO THE I80 CORRIDOR EAST OF THE QUAD
CITIES BY MIDNIGHT. WILL KEEP HIGH POPS GOING ACRS MUCH OF THE
NORTHERN 2/3S OF THE CWA FOR OCCASIONAL BANDS OF RAIN...BUT STILL
SEE THE SCENARIO OF RAIN TEMPERING DOWN TO DRIZZLE BETWEEN THE
ORGANIZED FORCING. IF THIS HAPPENS...NORTH TO NORTHEAST LIGHT
CYCLONIC CONVERGENT FLOW ON NORTH SIDE OF LLVL CIRCULATION MAY
INDUCE AREAS OF FOG SOME OF WHICH MAY BE DENSE. FOR NOW WILL
INTRODUCE THE FOG POTENTIAL WITH PATCHY WORDING ACRS MAINLY THE
NORTHEASTERN HALF OF THE FCST AREA. SOME DELAY IN IN-WRAPPING POST
WAVE WEST TO NORTH-WESTERLIES...BUT THAT OCCURRENCE WILL STILL LOOK
TO FLOW ACRS THE CWA AFTER MIDNIGHT INTO EARLY TUE MORNING AND BLOW
OUT ANY LINGERING FOG. BACK TO THE EARLIER EVENING PERIOD... IN-
WRAPPING LOW TO MID LEVEL DRY SLOT ON SOUTH END OF THE LOW COMPLEX
MAY STILL LOOK TO INTERACT WITH DEEPER MOISTURE BAND TO PRODUCE
SOME EMBEDDED THUNDER ON SOUTH FLANK OF ANY PRECIP BAND/BANDS IN
THE SOUTHERN CWA AND WILL ADD SOME THUNDER MENTION IN THOSE AREAS
THROUGH 03Z TUE. ADDITIONAL PRECIP AMOUNTS AFTER 00Z TUE WILL BE
MAINLY A TENTH OF AN INCH OR LESS...ALTHOUGH LOCALIZED HIGHER
AMOUNTS MAY OCCUR IN THE SOUTH IF SOME THUNDER DOES INDEED OCCUR
IN THOSE AREAS. LATE LLVL COOL AIR FLUSH INTO THE AREA WILL DROP
LOW TEMPS INTO THE LOWER 30S IN THE FAR WEST BY SUNRISE TUE...
WHILE THE FAR EAST MAY STILL BE AROUND 40. BULK OF PRECIP WILL
STILL LOOK TO EXIT THE AREA BY THE TIME THE COLUMN TOP-DOWN COOLS
ENOUGH FOR THE PRECIP TO CHANGE OVER TO SNOW. LOW LEVEL COLD
UNDERCUT MAY PRODUCE A BRIEF WINDOW OF SLEET BY TUE MORNING...BUT
WILL NOT ADD THOSE DETAILS AT THIS POINT. MINIMAL IF ANY SNOW
ACCUM ON WET GROUND IN AREAS THAT GO OVER TO ALL SNOW TUE MORNING.
TUE STILL TO BE A RAW BLUSTERY DAY WITH NORTHWEST WINDS OF 15-30
MPH AND STEADY TO FALLING TEMPS AS THE DAY PROGRESSES...12 HR
HIGHS DURING THE MORNING. FUJIWARA-ING SECONDARY LOW DROPPING
SOUTHEASTWARD ACRS THE WESTERN GRT LKS LATER TUE NIGHT INTO WED TO
HAVE LITTLE EFFECT ON THE LOCAL AREA AS STRONG SFC RIDGE LOBE
EXTENDS DOWN ACRS THE MO RVR VALLEY AND IA. WRAP AROUND CLOUDS MAY
HAVE AN EFFECT...BUT WILL KEEP COLD TEMPS GOING TUE NIGHT IN THE
TEENS TO LOWER 20S.

WEDNESDAY THROUGH NEXT SUNDAY...WILL BANK ON THE 12Z ECMWF MID CONUS
HIGH STRENGTH KEEPING THE FCST MAINLY DRY AND COLD WED THRU THU...AS
OPPOSED TO THE 12Z GFS AND GEM THAT TRIES TO PRODUCE AN ISENTROPIC
LIGHT SNOW EVENT IN THE SOUTHERN CWA WED NIGHT. THE EURO DOES TRY TO
BREAKOUT SOME FLURRIES ACRS THE FAR SOUTH TO LEE OF SOUTHERN PLAINS
LLVL CYCLOGENESIS ON THU...BUT EVEN LOW POPS MAY BE OVERDOING IT FOR
THIS POTENTIAL AT THIS POINT. EYES THEN TURN TO LINGERING SOUTHERN
STREAM TROFFINESS ACRS THE SOUTHWESTERN CONUS THU INTO FRI. PHASING
AND UPPER JET STREAM INTERACTION WILL BE A LARGE DRIVER OF COURSE...
WITH THE 12Z GFS MORE BULLISH WITH SOME INTERACT ALLOWING A MORE
DEVELOPED LOW PRESSURE SYSTEM AND EVENTUAL FURTHER NORTHWEST PULL-
OUT OF A STORM...ENOUGH SO THAT IT PRODUCES HEADLINE WORTHY SNOW
AMOUNTS ACRS AT LEAST THE SOUTHEASTERN THIRD OF THE DVN CWA FRI
NIGHT INTO SAT MORNING. BULK OF OTHER MEDIUM RANGE SOLUTIONS ARE LESS
PHASED AND DEVELOP/ROLL A STRONG SOUTHERN STEAM WAVE WELL TO THE
SOUTH OF THE AREA TOWARD THE GULF AT THE START OF THE WEEKEND. FOR
NOW WILL MAINTAIN LOW CHC POPS FOR SNOW IN THE SOUTH FRI NIGHT INTO
SAT AS A GO-BETWEEN...BUT CURRENT UPSTREAM JET TRENDS AND LARGE
SCALE WAVE TRENDS SUGGEST THE ECMWF AND GEM MAY BE MORE IN LINE. BUT
A DEFINITE WINDOW TO WATCH IN UPCOMING MODEL RUNS OVER THE NEXT 24-
48 HRS. AS FOR TEMPS...WILL CONTINUE COLDER THAN NORMAL LATE WEEK AND
INTO THE WEEKEND TO NORTH OF THE ACTIVE SOUTHERN STREAM.    ..12..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 623 PM CST SUN DEC 14 2014

VLIFR CEILINGS AND VISIBILITY TO CONTINUE OVERNIGHT AT KDBQ BEFORE
IMPROVE AROUND 13Z AS RAIN ARRIVES FROM THE SOUTH. CIGS/VSBYS NOT
EXPECTED TO BE QUITE AS LOW AT KCID/KMLI/KBRL. HAVE RAIN TIMED
INTO KBRL AT 10Z...11Z AT KCID...12Z AT KMLI. RAINFALL INTENSITY
EXPECTED TO SLACKEN MONDAY AFTERNOON WITH PERIODS OF DRIZZLE AND
IFR/MVFR CONDITIONS.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 8 AM CST MONDAY FOR BUCHANAN-CEDAR-
     CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-MUSCATINE-SCOTT.

IL...DENSE FOG ADVISORY UNTIL 8 AM CST MONDAY FOR BUREAU-CARROLL-
     HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-
     STEPHENSON-WARREN-WHITESIDE.

MO...NONE.
&&

$$

UPDATE...RP KINNEY
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...12
AVIATION...RP KINNEY





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