Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 142001
AFDDVN

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

.UPDATE...
ISSUED AT 159 PM CST SUN DEC 14 2014

WITH SOUTHEAST WINDS CONTINUING TO SLIGHTLY ENHANCE CONVERGENCE
AND SLOW THE ADVANCE OF THE BETTER MIXED AIR TO THE SOUTH...THE
NORTHERN 1/4 OF THE CWA NOW LOOKS TO REMAIN IN THE DENSE FOG THE
REST OF TODAY...THROUGH TONIGHT. A NEW DENSE FOG ADVISORY HAS BEEN
ISSUED TO COVER THIS EXTENDED THREAT.
ERVIN

UPDATE ISSUED AT 932 AM CST SUN DEC 14 2014

THE HODGE PODGE OF GOOD AND POOR VISIBILITY THAT WAS COVERED BY SPS
PRODUCTS NOW HAS SHOWN SIGNS OF WHERE IT WILL BECOME MORE
PERSISTENT. WEAK CONVERGENCE WITH SOUTH WINDS OVER SOUTH IOWA AND
SOUTHEAST WINDS BETWEEN WATERLOO AND MUSCATINE HAVE RESULTED IN A
STRIPE OF VERY POOR VISIBILITY...NEAR ZERO IN SOME LOCATIONS. THAT
SHOULD LAST AS LONG AS THE CONVERGENCE DOES...OR AROUND NOON.
OTHERWISE...THE SCATTERED 1/4 VISIBILITIES TO THE SOUTHEAST AND
EAST HAVE LIFTED TO AROUND 1 MILE OR BETTER AS OF 930 AM.

ERVIN

&&

.SYNOPSIS...
ISSUED AT 340 AM CST SUN DEC 14 2014

WARM FRONT CONTINUES TO LIFT NORTHWARD THROUGH THE CWA WITH
SOUTHERLY WINDS KEEPING TEMPERATURES ON THE MILD SIDE...IN THE 40S
AT 3 AM. VISIBILITIES WERE MAINLY IN THE 1 TO 5 MILE RANGE WITH
LOW STRATUS COVERING MUCH OF THE MIDDLE OF THE COUNTRY.

3 AM TEMPERATURES WERE IN THE 50S FROM SIOUX FALLS TO DES MOINES
SOUTHWARD TO THE SOUTHERN PLAINS...WITH SOME LOWER 60S IN TX.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST SUN DEC 14 2014

HEADLINES...LOOKING AT WEBCAMS/SURFACE OBS THE VISIBILITIES
CONTINUE TO IMPROVE TO ABOVE 1 MILE SO HAVE CANCELED THE DENSE FOG
ADVISORY FOR OUR FAR NORTHERN CWA. ANY PATCHY DENSE FOG CAN BE HANDLED
WITH A SPECIAL WEATHER STATEMENT IF NEEDED.

TODAY...SHARP NEGATIVELY-TILTED UPPER LEVEL TROUGH COMING OUT OF
THE ROCKIES WILL EVOLVE INTO A CLOSED LOW AS IT PUSHES INTO THE
SOUTHERN PLAINS. SOUTHERLY WINDS AHEAD OF THIS STRONG SYSTEM WILL
PUMP UNSEASONABLY WARM TEMPERATURES INTO THE DVN CWA...AND WE WILL
BE SOLIDLY IN THE WARM SECTOR. AREAS OF FOG CAN BE EXPECTED THIS
MORNING BUT WITHOUT ANY FORCING I HAVE REMOVED MENTION OF DRIZZLE.
THIS WILL BE ANOTHER DAY OF WIDESPREAD STRATUS WITH THE POSSIBILITY
OF A FEW BREAKS IN THE OVERCAST THIS AFTERNOON. DESPITE THE CLOUDS
THIS WILL BE A WARM DAY FOR MID DECEMBER STANDARDS...WITH HIGHS IN
THE 50S MOST LOCATIONS. OUR FAR SW CWA WILL BE APPROACHING 60.
WHILE NOT EXPECTING ANY RECORDS TO BE BROKEN IT WILL BE CLOSE AT
KDBQ/KCID. SEE CLIMATE SECTION BELOW.

TONIGHT...DRY THIS EVENING THEN STACKED UPPER LOW WILL BE TRACKING
ACROSS KANSAS. OPERATIONAL MODELS SIMILAR IN DEPICTING A WARM
CONVEYOR BELT OF DEEP MOISTURE PUSHING INTO OUR SW CWA AFTER
MIDNIGHT. POPS HAVE BEEN RAISED EVEN FURTHER THERE. PRECIPITABLE
WATERS INCREASE TO NEAR 1 INCH BY MORNING IN OUR SW. IN OUR NE CWA
IT SHOULD REMAIN DRY. LOOKS TOO STABLE FOR ANY THUNDER SO DID NOT
MENTION IN GRIDS. ANOTHER MILD NIGHT WITH LOWS IN THE 40S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM CST SUN DEC 14 2014

MILD WITH RAIN MONDAY... THEN NEAR NORMAL AND MAINLY DRY.

VERTICALLY STACKED /OCCLUDED/ STORM SYSTEM TO MOVE ACROSS THE REGION
MONDAY NGT INTO EARLY TUE. ARCING MOIST CONVEYOR (DENOTED BY AXIS
OF SURGING PWATS TO AROUND 1 INCH OR 2 STANDARD DEVIATIONS ABOVE
NORMAL) COUPLED WITH DIVERGENCE ALOFT ATTENDANT TO LEFT EXIT REGION
OF SOUTHERN PLAINS TO LOWER MISSISSIPPI VLY JET EXPECTED TO FUEL
BAND OF RAIN OR SHOWERS LIFTING FROM SOUTH TO NORTH ACROSS THE CWA
MONDAY. THE FORCING PEAKS ACROSS SOUTHERN CWA MONDAY AM... THEREFORE
ANTICIPATE THE BAND OF RAIN TO GRADUALLY WEAKEN AS IT LIFTS NORTHWARD
MONDAY. THEN... ANTICIPATE SECONDARY AREA OF RAIN OR SHOWERS TO
DEVELOP MONDAY AFTN CLOSER TO VERTICALLY STACKED LOW AND MOVE ACROSS
PORTIONS OF CWA THROUGH MONDAY EVE. DESPITE PWATS 2+ STANDARD DEVIATIONS
ABOVE NORMAL... DURATION OF FORCING AT ANY ONE LOCATION SHOULD LIMIT
RAINFALL TO MOSTLY LIGHT AMOUNTS OF 0.25 INCH OR LESS... BUT EXPECT TO
SEE SOME AREAS OF MODERATE AMOUNTS OF 0.30 TO 0.60 INCH. SOME POTENTIAL
FOR BRIEF TRANSITION PERIOD OF A LIGHT WINTRY MIX TO SNOW LATE
MONDAY NGT INTO EARLY TUE AM... MAINLY NORTH OF I-80 AND ESPECIALLY
PORTIONS OF NORTHEAST IA WITH COLD CONVEYOR AND WEAKENING DEFORMATION
ZONE.

TUESDAY AND TUESDAY NIGHT...ANY LIGHT RAIN OR LIGHT SNOW LOOKS TO
TAPER OFF TUESDAY AM WITH BOUT OF MID LEVEL SUBSIDENCE BETWEEN
DEPARTING SYSTEM AND NORTHERN STREAM SYSTEM OVER UPPER MIDWEST AND
NORTHERN GREAT LAKES. THIS MAY RESULT IN SOME BREAKS IN CLOUDS AND
PEAKS OF SUNSHINE TUESDAY AFTN. TEMPS COULD REBOUND A FEW DEGS
AS RESULT OF ANY SUNSHINE... BUT OVERALL EXPECT NEARLY STEADY TEMPS
TUESDAY AND MAINLY IN THE 30S WITH BRISK NORTHWEST WINDS 10-20+ MPH.
TUESDAY NIGHT LOOKS TO BE DRY AND COLD WITH DECREASING CYCLONIC FLOW
BETWEEN DEPARTING GREAT LAKES SYSTEM AND INCOMING HIGH PRESSURE. THE
INCREASING SUBSIDENCE IS LIKELY TO BRING AT LEAST PARTIAL CLEARING
TUESDAY NGT ALLOWING LOWS TO DIP DOWN INTO THE UPPER TEENS TO MID 20S.

WEDNESDAY AND WEDNESDAY NIGHT...CONTINUED DRY WITH SURFACE HIGH PRESSURE
IN CONTROL. TEMPS TO BE NEAR NORMAL WITH HIGHS AROUND 30 OR L30S
AND LOWS IN THE TEENS TO AROUND 20.

THURSDAY THROUGH SATURDAY...SPLIT FLOW PATTERN ALOFT SET TO DOMINATE
AND TYPICALLY THIS IS A DRIER AND NEAR NORMAL TEMP REGIME FOR THE
REGION. WILL HAVE TO KEEP WATCH THOUGH ON THE TRACK OF EJECTING SOUTHERN
STREAM SYSTEM LATE WEEK INTO THE WEEKEND. DUE TO THE SPLIT FLOW PATTERN
THE MEDIUM RANGE MODELS CONTINUE TO STRUGGLE WITH TRACK AND TIMING OF
THIS SYSTEM. OPERATIONAL GFS APPEARS TO BE FURTHER NORTH AND STRONGER
OUTLIER COMPARED WITH ENSEMBLE MEAN WHICH SUPPORTIVE OF FURTHER SOUTH
TRACK FROM LOWER MISSISSIPPI VLY TO OHIO VLY WHICH IS CLOSE TO 00Z
ECMWF TRACK AND ALSO HAS SOME SUPPORT FROM GEM AND UKMET AT 144 HRS.
THIS MORE SOUTHERLY TRACK THOUGH COULD STILL RESULT IN THE SOUTHERN
CWA POTENTIALLY BEING BRUSHED BY SOME LIGHT SNOW AT SOME POINT IN THE
THU-SAT TIMEFRAME.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1122 AM CST SUN DEC 14 2014

A CHALLENGING AVIATION FORECAST REMAINS FOR EASTERN IOWA AND
NORTHWEST ILLINOIS WITH RESPECT THE FINE DETAILED TRANSITIONS FROM
LIFR TO IFR AND BACK AGAIN AS FOG LIFTS NORTH TODAY...FOLLOWED BY
FOG AND RAIN MOVING BACK OVER THE REGION LATER TONIGHT AND
LINGERING THROUGH THE DAY MONDAY. HOWEVER...A BROAD FOCUS THAT
CONDITIONS WILL REMAIN VERY POOR FOR AVIATION IS CERTAIN...AND
MANY SITES WILL BE NEAR OR AT MINIMUMS AT TIMES THROUGH THE NEXT
24 PLUS HOURS. SOUTHEAST WINDS CONTINUE TO PUMP MOISTURE UP OVER
THE REGION...AND CIGS WILL VARY BETWEEN 100 AND 600 FT TODAY AS
THIS OCCURS. VISIBILITIES INITIALLY AROUND 1/4 MILE NORTH OF
INTERSTATE 80 WILL LIFT TO AROUND 3 MILES THIS AFTERNOON...BUT
WILL AGAIN FALL BACK TO AROUND 1/2 MILE TONIGHT. RAIN MAY HELP
IMPROVE VISIBILITIES SOME MONDAY...BUT THIS IS NOT CERTAIN YET.
ERVIN


&&

.CLIMATE...
ISSUED AT 300 AM CST SUN DEC 14 2014

RECORD HIGHS FOR DECEMBER 14...

MOLINE.........61 IN 1975
CEDAR RAPIDS...58 IN 2006
DUBUQUE........55 IN 1975
BURLINGTON.....62 IN 2008

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 6 AM CST MONDAY FOR BUCHANAN-DELAWARE-
     DUBUQUE-JACKSON-JONES.

IL...DENSE FOG ADVISORY UNTIL 6 AM CST MONDAY FOR JO DAVIESS-
     STEPHENSON.

MO...NONE.
&&

$$

UPDATE...ERVIN
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...05
AVIATION...ERVIN
CLIMATE...HAASE





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