Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 151413
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
813 AM CST MON DEC 15 2014

.UPDATE...
ISSUED AT 812 AM CST MON DEC 15 2014

HAVE LET THE DENSE FOG ADVISORY EXPIRE AT 8 AM BUT VISIBILITIES
WILL REMAIN AT MAINLY 2 TO 4 MILES ACROSS THE CWA FOR MUCH OF THE
DAY. OFF AND ON BANDS OF RAIN WILL MOVE ACROSS THE CWA DURING THE DAY.

UPDATE ISSUED AT 603 AM CST MON DEC 15 2014

RAIN BAND CONTINUES TO SPREAD NORTHEAST ACROSS OUR SOUTHERN AND
WESTERN COUNTIES. AHEAD OF THE RAIN SOUTHEAST WINDS HAVE INCREASED
TO 10 TO 20 MPH AND VISIBILITIES HAVE IMPROVED TO ABOVE 2 MILES.
THEREFORE...THE DENSE FOG ADVISORY HAS BEEN CANCELLED. THE EXCEPTION
IS UP ALONG HIGHWAY 20 FROM INDEPENDENCE IOWA TO FREEPORT IL WHERE
SOME LOCAL DENSE FOG WAS STILL BEING REPORTED. WE SHOULD BE ABLE
TO CANCEL THE REMAINING PORTION OF THE ADVISORY BY 8 AM IF NOT SOONER.

ELSEWHERE...LIGHTNING STRIKES WERE OCCURING IN EASTERN KS ASSOCIATED
WITH THE UPPER LOW AND WILL MAINTAIN THE MENTION OF ISOLATED THUNDERSTORMS
IN THE GRIDS FOR THIS AFTERNOON.

&&

.SYNOPSIS...
ISSUED AT 300 AM CST MON DEC 15 2014

OCCLUDED/STACKED CYCLONE CENTERED IN CENTRAL KS WITH A WARM CONVEYOR
BELT BAND OF RAIN THAT EXTENDED FROM CENTRAL IA TO EASTERN MO INTO
ARKANSAS...LIFTING NORTHEAST. ON THE NW SIDE OF THE CYCLONE IN THE
COLDER AIR THERE IS LIGHT TO MODERATE SNOW IN WESTERN NEBRASKA AND
EVEN SOME FREEZING RAIN IN CENTRAL NEBRASKA. AHEAD OF THE RAIN THERE
WAS WIDESPREAD DENSE FOG FROM NORTHERN IA TO NORTHERN IL AND ON INTO
MN...WI AND MI. A FEW THUNDERSTORMS HAVE BEEN NOTED AROUND THE CLOSED
LOW IN THE CENTRAL/SOUTHERN PLAINS.

3 AM TEMPERATURES IN THE DVN CWA WERE IN THE MID TO UPPER 40S WITH
50S FROM CENTRAL/WESTERN IA TO OK/AR WITH SOME 60S IN TX.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CST MON DEC 15 2014

HEADLINES...DENSE FOG WAS LOCATED IN NORTHEAST IA/NORTHWEST IL AND
THE ADVISORY LOOKS GOOD THERE. HOWEVER...FARTHER SOUTH VISIBILITIES
WERE IN THE 1 TO 4 MILE RANGE. FOR NOW I WILL CONTINUE WITH THE
DENSE FOG ADVISORY AS IS UNTIL 8 AM WHEN THE ARRIVAL OF RAIN
SHOULD DISSIPATE OR IMPROVE THE CONDITIONS. HOWEVER...IF THE RAIN
IS DELAYED SOMEWHAT THEN WE MAY NEED TO EXTEND PORTIONS OF THE ADVISORY
THROUGH MUCH OF THE MORNING.

TODAY...DENSE FOG WILL STILL PLAGUE NORTHEAST IA AND NW IL UNTIL
THE RAIN ARRIVES. MEANWHILE...THE CENTER OF STACKED LOW SHOULD
PUSH TO NEAR OTTUMWA BY EVENING WITH OPERATIONAL MODELS SPREADING
THE BAND OF STEADY RAIN ACROSS THE CWA THIS MORNING...AS THE
STRONGER FORCING ARRIVES AND PRECIPITABLE WATERS INCREASE TO NEAR
1 INCH. DURING THE AFTERNOON THE MODELS SUGGEST THE RAIN MAY BECOME
MORE SCATTERED IN COVERAGE AND CURRENT POPS MAY BE TOO HIGH...DAY
SHIFT CAN EVALUATE. LAPSE RATES STEEPEN SOMEWHAT AS THE POCKET OF
COOLER AIR ALOFT ARRIVES THIS AFTERNOON WITH THE UPPER LOW. I WILL
MAINTAIN THE ISOLATED WEAK THUNDERSTORMS IN THE GRIDS. HOWEVER...ANY
STRONGER STORMS SHOULD REMAIN WELL SOUTH OF THE CWA WHERE THE BETTER
INSTABILITY WILL BE LOCATED. RAINFALL AMOUNTS SHOULD BE LESS THAN
ONE-HALF INCH AT MOST LOCATIONS. TEMPERATURES WILL STILL BE MILD
AHEAD OF THE STORM SYSTEM AND HIGHS MAINLY IN THE LOWER TO MID 50S
WILL BE IN THE GRIDS.

TONIGHT...STORM SYSTEM TRACKS TO NEAR CHICAGO WITH A DEFORMATION
ZONE ON THE BACK SIDE OF THE CYCLONE COMING ACROSS THE CWA. LIGHT
RAIN WILL CONTINUE MUCH OF THE NIGHT BUT COLDER AIR WILL BE FILTERING
INTO OUR WESTERN COUNTIES LATE TONIGHT...AND FORECAST SOUNDINGS
INDICATE A MIX OF RAIN/SNOW/SLEET THERE. CURRENT GUIDANCE INDICATES
LITTLE IF ANY ACCUMULATIONS OF ICE OR SNOW. MINIMUM TEMPERATURES
WILL RANGE FROM 30 AT INDEPENDENCE IOWA TO 42 AT PRINCETON ILLINOIS.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 AM CST MON DEC 15 2014

VERTICALLY STACKED CYCLONE TO ACCELERATE EAST OF CWA EARLY TUE AM
DUE TO FUJIWARA LIKE INTERACTION WITH DIGGING LOW OVER WESTERN
ONTARIO. SUBSEQUENT FORCING IN WRAPPING COLD CONVEYOR OF THE
EXITING CYCLONE WILL BE WANING TUE AM... THUS WHILE IT IS LIKELY
PORTIONS OF THE AREA (MAINLY EAST CTNRL/NE IA AND NW IL) WILL SEE
LIGHT RAIN TRANSITION TO A WINTRY MIX IT SHOULD BE ONLY FOR A SHORT
PERIOD. BULK OF FORCING WILL BE GOING TOWARD ERODING ELEVATED
WARM NOSE (+2 TO +4C 850-900 MB) WITH COLD AIR UNDERCUTTING AT THE
SFC... THUS FAVORABLE VERTICAL PROFILE TO SUGGEST THAT THE
BULK OF ANY LIGHT WINTRY MIX MAY FALL AS SLEET WITH POSSIBLY BRIEF
PERIOD OF FREEZING RAIN THEN PERHAPS SOME FLAKES AT THE TAIL END
BEFORE WRAPPING UP. DO NOT FORESEE ANY TRAVEL CONCERNS ATTIM WITH
WARM GROUND AND LITTLE IN THE WAY OF AMOUNTS. OTHERWISE... MAIN
STORY TUE WILL BE BLUSTERY AND COLDER CONDITIONS WITH STEADY TO SLOW
FALLING TEMPS ON NW WINDS 15-30 MPH. MID LEVEL SUBSIDENCE AND DRYING
ARRIVING DURING THE AFTN MAY ALSO RESULT IN AT LEAST PARTIAL
CLEARING OF THE CLOUDS. TUE NGT WILL SEE HIGH PRESSURE BEGIN TO BUILD
IN WITH DECREASING CYCLONIC FLOW AS ONTARIO LOW PASSES THROUGH THE
GREAT LAKES. ANTICIPATE SKIES MOCLR/PTCLDY WITH LOWS CLOSE TO NORMAL
IN THE TEENS AND LOWER 20S.

WEDNESDAY THROUGH SUNDAY... SPLIT FLOW TO GOVERN PATTERN ALOFT WHICH
SHOULD RESULT IN TYPICAL DECEMBER TEMPS WITH HIGHS MAINLY IN THE
UPPER 20S AND LOWER 30S...AND LOWS IN THE TEENS TO AROUND 20 DEGS.
SIDING ALSO TOWARD THIS PERIOD BEING LARGELY INFLUENCED BY SURFACE
HIGH PRESSURE AND THEREFORE MAINLY DRY. HAVING SAID THAT... A COUPLE
OF DISTURBANCES IN SOUTHERN STREAM WILL NEED WATCHING FOR POSSIBILITY
OF BRINGING PCPN (SNOW) TO THE CWA. FIRST SUCH DISTURBANCE LOOKS TO
EJECT EASTWARD FROM SOUTHERN PLAINS ON THURSDAY AND IS SUGGESTED TO
SHEAR/WEAKEN AS IT MOVES EAST INTO CONFLUENT FLOW. NONETHELESS... IT
COULD BRUSH SOUTHERN CWA WITH FLURRIES OR POSSIBLY SOME LIGHT SNOW BUT
THIS SHOULD NOT AMOUNT TO MUCH (SHOULD IT EVEN OCCUR) GIVEN THE
WEAKENING NATURE OF SYSTEM THAT WILL ALSO BE BATTLING DRY AIR ATTENDANT
TO HIGH PRESSURE RIDGE PARKED OVER THE REGION. WHAT BEARS MORE WATCHING
IS THE LATE FRI THROUGH SAT TIME-FRAME WHEN A SECONDARY AND MUCH
STRONGER DISTURBANCE IS SUGGESTED TO EJECT FROM THE SOUTHWEST U.S.
THE OPERATIONAL GFS AND GFS ENSEMBLE MEAN ARE FURTHER NORTH WITH THE
TRACK AND WOULD SUPPORT ACCUMULATING SNOW FOR AT LEAST MUCH OF THE
SOUTHERN HALF OF CWA LATE FRI INTO SAT. GREATEST SPREAD IN GFS ENSEMBLE
MEAN IS TO THE SOUTH AND SUGGESTIVE IF ANY DEVIATION WOULD BE MORE TO
THE SOUTH OF THE MEAN TRACK. THIS WOULD BE MORE IN LINE WITH LATEST
AND MORE SOUTHERLY TRACKS OF GEM...ECMWF AND UKMET WHICH ARE GENERALLY
SHOWING TRACK FROM SOUTHERN PLAINS TO THE OHIO VLY OR TENNESSEE VLY
WHICH RESULTS IN A BIG SWING AND MISS FOR CWA. FAVOR THE LATTER
SOLUTIONS WITH MORE SOUTHERLY TRACK AND DRIER SCENARIO ATTIM. BUT...
CONFIDENCE IS LOW AND MAY REMAIN SO FOR AT LEAST ANOTHER 24-48 HRS UNTIL
ENERGY CAN BE BETTER SAMPLED BY RAOB NETWORK. BEYOND... MAY HAVE YET
ANOTHER IN BARRAGE OF WEST COAST SYSTEMS TO WATCH FOR EARLY CHRISTMAS WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 554 AM CST MON DEC 15 2014

VLIFR/IFR CEILINGS AND VISIBILITY TO CONTINUE FOR MUCH OF TODAY
AND TONIGHT IN THE LOW STRATUS AND AREAS OF LIGHT FOG. PERIODS OF
RAIN CAN BE EXPECTED TODAY AND THERE MAY BE ISOLATED THUNDER THIS
AFTERNOON. A COLD FRONT WILL PUSH ACROSS THE TAF SITES AFTER 05Z/16
AND THERE MAY BE A MIX OF RAIN/SNOW AT KCID. SOUTHEAST WINDS 10 TO
20 KNOTS TODAY THEN WINDS BECOMING NORTH TO NORTHWEST 10 TO 20
KNOTS WITH GUSTS TO 25 KNOTS BEHIND THE COLD FRONT.


&&

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

$$

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





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