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000
FXUS63 KDVN 072347
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
547 PM CST FRI MAR 7 2014


.SYNOPSIS...
ISSUED AT 313 PM CST FRI MAR 7 2014

12Z UA ANALYSIS HAD AN 850MB LOW IN WESTERN KANSAS WITH A WARM FRONT
RUNNING UP INTO WESTERN IOWA. A MORE SUBSTANTIAL 850MB COLD FRONT
RAN FROM UPPER MICHIGAN INTO SOUTHEAST WYOMING. SATELLITE TRENDS
THROUGH MID AFTERNOON CONTINUE TO SHOW DEVELOPMENT OF LOW AND MID
LEVEL CLOUDS ACROSS IOWA. RADAR TRENDS HAVE SHOWN MAINLY MID LEVEL
CLOUDS BUT A BAND OF LIGHT PRECIPITATION IS DEVELOPING OVER
NORTHWEST IOWA.

18Z SFC ANALYSIS HAS AND COLD FRONT FROM ROUGHLY KIWD TO KFNB AND
BACK THROUGH WESTERN KANSAS. A SUBTLE PRE-FRONTAL TROF RAN FROM NEAR
KIWD TO KTOP. DEW POINTS WERE IN THE 30S ACROSS THE PLAINS AND MID
MISSISSIPPI VALLEY WITH 20S OVER THE NORTHERN PLAINS AND GREAT
LAKES.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 313 PM CST FRI MAR 7 2014

SO FAR THIS AFTERNOON VERY LITTLE IN THE WAY OF PRECIPITATION HAS
BEEN REPORTED IN THE OBSERVATIONS ACROSS IOWA. THUS MOST OF THE
RADAR RETURNS ARE PROBABLY LOWER CLOUDS. HOWEVER...RADAR TRENDS OVER
THE PAST FEW HOURS IS SUGGESTING A BAND OF PRECIPITATION DEVELOPING
FROM SOUTH OF KSUX TO NEAR KFOD. KCIN IS REPORTING SOME VERY LIGHT
PRECIPITATION AS OF 21Z.

QUIET AND DRY CONDITIONS WILL BE SEEN FOR THE REST OF THE AFTERNOON
ACROSS THE AREA. CLOUDS WILL CONTINUE TO INCREASE AS THE FRONT MOVES
THROUGH THE AREA. THE BETTER FORCING AND SATURATION ARE BEHIND THE
FRONT AND ARE NOT EXPECTED TO ENTER THE FAR NORTHWEST UNTIL AFTER
SUNSET.

BASED ON OVERALL TRENDS OF FORCING AND SATURATION...THE NARROW BAND
OF PRECIPITATION IN WESTERN IOWA SHOULD CONTINUE TO DEVELOP AND MOVE
EAST NORTHEAST AND CATCH THE HIGHWAY 20 CORRIDOR WEST OF DUBUQUE
EARLY THIS EVENING. DUE TO THE WARM TEMPERATURES...THE PRECIPITATION
SHOULD BEGIN AS RAIN.

LATER THIS EVENING FORCING AND SATURATION INCREASES FURTHER. A
STEADY BAND OF PRECIPITATION SHOULD REMAIN ACROSS THE FAR
NORTH/NORTHWEST BUT EVAPORATIVE COOLING SHOULD RESULT IN A MIX
DEVELOPING THAT EVENTUALLY CHANGES OVER TO LIGHT SNOW. AT BEST A
TRACE OF SNOWFALL WILL OCCUR.

AFTER MIDNIGHT...FORCING AND SATURATION FINALLY OCCURS ACROSS THE
ENTIRE AREA ASSOCIATED WITH ANOTHER DISTURBANCE MOVING NORTHEAST
FROM THE PLAINS. RAIN WILL BECOME MORE WIDESPREAD ACROSS THE AREA
THAT WILL CHANGE TO SNOW DUE TO EVAPORATIVE COOLING. THERE WILL
PROBABLY BE A BRIEF PERIOD OF SLEET THAT OCCURS DURING THE CHANGE
OVER. SNOWFALL AMOUNTS WILL BE WELL UNDER AN INCH ACROSS THE AREA.

INTERNALLY...THE FORCING IN THE MODELS IS SUGGESTING A NARROW BAND
OF SNOW ACROSS THE CENTRAL PARTS OF THE CWFA. IF THIS OCCURS...THERE
MAY BE SOME LOCALIZED SNOWFALL AMOUNTS APPROACHING AN INCH.

SATURDAY MORNING...LIGHT SNOW SHOULD BE FALLING ACROSS THE SOUTHEAST
HALF OF THE AREA AS THE BETTER FORCING BEGINS TO EXIT THE AREA. MOST
OF THE SNOWFALL ACCUMULATION WOULD OCCUR SHORTLY AFTER SUNRISE AND
OVERALL AMOUNTS SHOULD BE A DUSTING AT BEST.

THERE MAY OR MAY NOT BE SOME LINGERING LIGHT SNOW/FLURRIES ACROSS
THE FAR SOUTHEAST IN THE EARLY AFTERNOON. HOWEVER...THE OVERALL
TREND WILL BE FOR SKIES TO CLEAR FROM NORTHWEST TO SOUTHEAST DURING
THE AFTERNOON.    ..08..

.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 313 PM CST FRI MAR 7 2014

SATURDAY NIGHT THROUGH MONDAY...SFC RIDGE STILL SLATED TO SLIDE ACRS
THE REGION SAT NIGHT...SFC WIND DECREASE TO LIGHT AND VARIABLE AND
MINIMAL SKY COVER MAY FOSTER SOME FOG DEVELOPMENT BUT COVERAGE/
EXTENT OF IT STILL QUESTIONABLE ENOUGH NOT TO MENTION IN THE
GRIDS/ZONES FOR NOW. QUICK TEMP DROP-OFF EXPECTED SAT EVENING...WITH
LOWS MAKING IT INTO THE SINGLE DIGITS IN SOME LOCATIONS NORTH OF
I80. RIDGE PROGRESSIVE ENOUGH TO ALLOW SOME LIGHT RETURN FLOW TO
COMMENCE BEFORE DAWN SUNDAY FOR A TEMP STEADY-OUT OR RISE TREND WEST
OF THE MS RVR. DE-AMPLIFIED STEERING FLOW PATTERN WILL STILL LOOK TO
ACT AS A WAVE/CLIPPER SHUTTLE FROM SOUTH CENTRAL CANADA TO THE
EASTERN GRT LKS INTO EARLY NEXT WEEK. THE LOCAL AREA STILL TO BE ON
THE WARM SECTOR SIDE OF THESE WAVES WITH ROBUST WARM AIR ADVECTION
FROM THE PLAINS INCREASING INTO MONDAY. HIGHS SUNDAY MAY BE SIMILAR
TO WHAT IS OCCURRING TODAY...LOWS SUNDAY NIGHT MAY NOT DIP BELOW 30
DEGREES OR EVEN FREEZING IN MUCH OF THE AREA IF SOUTHWEST SFC WINDS
STAY COUPLED. WARM DRAW ON MON IMPRESSIVE...BUT FCST SOUNDINGS
SUGGEST SHARP/STOUT INVERSION DEVELOPING ALOFT THAT MAY LIMIT MIXING
DEPTH AND THE TRUE WARM UP POTENTIAL. EVEN LOW END MIXING TO BASE OF
THE INVERSION SUPPORTS HIGHS IN THE UPPER 40S NORTH OF HWY
30...PLENTY OF 50S TO THE SOUTH OF THERE...AND SOME 60/LOWER 60S IN
THE FAR SOUTH. MIXING TO AROUND H9 MB SUPPORTS MORE WIDESPREAD 60S
EVEN NORTH OF I80. SNOW COVER TO BE DETERIORATED IN MANY LOCATIONS
BY THEN AS WELL. WILL BUILD UPON THE PREVIOUS SHIFT/S WARMING TREND.

TUESDAY AND WEDNESDAY...WITH THE LARGE MODEL RUN-TO-RUN DIFFERENCES
AND DISCONTINUITIES WITH WAVE PHASING PROCESS ACRS THE MID CONUS...
ALMOST HAVE LESS CONFIDENCE WHAT WILL HAPPEN THIS PERIOD THEN
YESTERDAY AT THIS TIME. THE 12Z GFS IS LESS DEVELOPED/PHASED AND
ADVERTISES JUST A MINOR RAIN-SNOW MIX OR WET SNOW EVENT FOR PORTIONS
OF THE CWA LATE TUE INTO EARLY WED. THE 12Z ECMWF MORE PHASED AND
DEVELOPS A POTENT SYSTEM BUT STILL FAR ENOUGH TO THE SOUTH THAT IT
JUST CLIPS THE SOUTHERN THIRD OF THE FCST AREA WITH RAIN/SNOW MIX
GOING INTO SOME ACCUMULATING WET SNOW TUE NIGHT INTO WED. THE LLVL
PATH OF THE CYCLONE DEVELOPED BY THE 12Z CANADIAN GEM STILL SUGGESTS
THE DVN CWA TO BE IN THE CROSS-HAIR OF IT/S ASSOCIATED DEF ZONE
PRECIP BAND...BUT IT IS WEAKER AND WOULD ONLY PRODUCE 1-3 INCHES OR
2-4 INCHES OF WEST SNOW TUE NIGHT AFTER RAIN OR RAIN/SNOW MIX
TRANSITIONS INTO ALL SNOW. IT MAY TAKE ANOTHER 24-48 HRS OF MODEL
RUNS FOR THEM TO HAMMER THIS SCENARIO OUT FOR MORE CONFIDENCE...BUT
WILL KEEP CHC POPS RIDING FOR NOW AND A WATCH-FULL EYE FOR THIS
POTENTIAL EARLY SPRING STORM SYSTEM TOWARD THE MIDDLE OF NEXT WEEK.

NEXT THURSDAY AND FRIDAY...ANOTHER CHANGE IN THE MEDIUM RANGE
SOLUTIONS FROM YESTERDAY...IS THAT THE NORTHWEST FLOW-L/W TROF THAT
DEVELOPS ACRS THE UPPER MIDWEST/MS RVR VALLEY IN THE WAKE OF WHAT
EVER STORM SYSTEM THAT CAN DEVELOP TUE-WED...IS MORE PROGRESSIVE AND
SHIFTS EASTWARD FOR A LIMITED COOL DOWN. WED MAY STILL HAVE HIGHS
ONLY IN THE 30S...BUT NOW THE LONGER RANGE INDICATIONS THU INTO FRI
COULD HAVE SUBSTANTIAL THERMAL MODERATION BACK TO AROUND NORMAL OR
EVEN ABOVE NORMAL BY FRIDAY. TEMPORARY WEAK REX BLOCK OUT WEST
WEAKENS EVEN MORE...THE FLOW FLATTENS WITH THE NORTHERN STREAM
BECOMING ACTIVE ACRS CANADA INTO THE NORTHEASTERN GRT LKS AGAIN. THE
CWA AGAIN MAY BE ON THE WARM SECTOR SIDE OF THESE WAVES INTO THE
START OF NEXT WEEKEND...SIMILAR TO WHAT SETS UP FOR THE SECOND HALF
OF THIS WEEKEND AND INTO EARLY NEXT WEEK. BUT PLENTY OF TIME FOR THE
MEDIUM RANGE SOLUTIONS TO CHANGE THEIR TUNE AGAIN AND WILL HAVE TO
STILL WATCH FOR DEEPENING AND MORE PERSISTENT L/W TROF ESTABLISHMENT
ACRS THE UPPER MS RVR VALLEY LATE NEXT WEEK.    ..12..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM CST FRI MAR 7 2014

VFR WX WILL DETERIORATE FROM NW TO SE TO MVFR VSBYS/CIGS BY 08/03Z
BEHIND A COLD FRONT MOVING THROUGH EASTERN IOWA AND ILLINOIS. WINDS
WILL SHIFT TO THE NORTHWEST TO NORTH AT 8-14 KTS. AFT 08/03Z...MVFR
CONDITIONS WILL BECOME SCATTERED WITH AREAS OF LIGHT RAIN CHANGING
TO LIGHT SNOW. SLEET MAY BE BRIEFLY POSSIBLE DURING THE TRANSITION.
ALTHOUGH THE PROBABILITY IS LOW...THE POTENTIAL DOES EXIST FOR IFR
CONDITIONS TO DEVELOP WITH THE SNOW. ANY AREAS OF LIGHT PRECIPITATION
WILL MOVE EAST BY 08/12Z WITH GRADUALLY CLEARING BY 08/19Z.

&&

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

&&

$$

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