Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 251811
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
111 PM CDT WED MAR 25 2015

.SYNOPSIS...
ISSUED AT 338 AM CDT WED MAR 25 2015

AT 3 AM...A WEAK SURFACE LOW WAS LOCATED JUST WEST OF PEORIA WITH
MSAS INDICATING AN AXIS OF STRONG PRESSURE FALLS OVER CENTRAL LAKE
MI SUPPORTING CONTINUED RAPID NORTHEASTWARD MOVEMENT OUT OF THE
REGION BY SUNRISE. KDVN 88D AND SURFACE REPORTS SHOWED THE BACK EDGE
OF LIGHT FREEZING RAIN...RAIN AND SNOW MAINLY NORTHEAST OF A LINE
FROM PRINCETON IL TO MONTICELLO IA. THE STRONGEST UPPER VORT MAX AND
MCS WAS OVER SOUTHERN INDIANA...EMBEDDED IN A TROUGH AXIS REACHING
FROM A LOW OVER FAR NW MN SE ACROSS EASTERN IA TO SOUTHERN INDIANA.
A STRONGER LOW WAS NEARLY VERTICALLY STACKED OVER EASTERN ND WITH A
COLD FRONT REACHING SOUTH AND SOUTHWEST ACROSS SD. BETWEEN THE TWO
SURFACE LOWS...LOW CLOUDS AND LIGHT FOG WERE WIDESPREAD ACROSS
MN...IA AND NORTHERN IL WITH TEMPERATURES MAINLY IN THE 30S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CDT WED MAR 25 2015

TEMPERATURES AND POTENTIAL FOR LIGHT PRECIPITATION LATER TODAY ARE THE
PRIMARY FORECAST CHALLENGES.

WITH THE EXTENSIVE LOW CLOUDS ALREADY IN PLACE...WEAK SURFACE PRESSURE
FIELDS AND INCOMING MID CLOUDS FROM THE CENTRAL PLAINS...SKIES WILL
REMAIN CLOUDY THROUGH THE MORNING. THERE MAY BE SOME PARTIAL CLEARING
ACROSS ESPECIALLY THE NORTH BY AFTERNOON AS THE PLAINS FRONT PUSHES
INTO THE FORECAST AREA MIXING OUT THE LOW LEVEL MOISTURE...BUT BY THIS
TIME MID LEVEL FORCING AHEAD OF A SHORTWAVE ADVANCING FROM THE ROCKIES
WILL PROVIDE HIGH CLOUD COVER. THE RESULT SUGGESTS AN OVERALL CLOUDY
DAY...WHICH SHOULD AGAIN LEAD TO LOWERED EXPECTATIONS FOR DAYTIME HIGHS.
FOLLOWING THE LEAD OF SHORT TERM MODELS THAT HAVE PICKED UP ON THIS...WILL
HAVE HIGHS OPTIMISTICALLY FROM THE MID 40S NORTH TO LOWER 50S SOUTH
COUNTING THE EFFECTS OF DEEPER MIXING WITH THE AFTERNOON FRONTAL PASSAGE.

THE ADVANCING MID LEVEL SHORTWAVE AND ASSOCIATED AXIS OF FRONTOGENESIS
TAKES AIM ON THE SOUTH THIS AFTERNOON. THIS FEATURE... ALREADY PRESENT
ACROSS CENTRAL AND WESTERN NEB...WILL INITIALLY BE WEAK WITH POSSIBLE
SPRINKLES ALONG THE HIGHWAY 34 CORRIDOR BY MID AFTERNOON...BUT THEN
BECOMES STRONGER TOWARD 00Z AS PHASING MID LEVEL TROUGHS INTENSIFIES
THE FORCING WHICH SHOULD RESULT IN MORE WIDESPREAD SHOWERS ACROSS THE
FAR SOUTH. FOLLOWING THIS...HAVE SLIGHT CHANCE POPS THERE BY MID
AFTERNOON...THEN CHANCE TO LIKELY POPS BY EARLY EVENING THEN SHIFTING
SOUTHWARD WITH THE AXIS OF FRONTOGENETICAL FORCING. LIMITED MOISTURE
WILL KEEP QPF AMOUNTS LESS THAN A TENTH OF AN INCH.

TONIGHT...A PASSING SYSTEM WELL TO THE SOUTH AND INCOMING MID LEVEL
SUBSIDENCE WILL STRENGTHEN LOCAL NW WINDS AND COLD AIR ADVECTION.
PREVIOUS FORECAST LOW TEMPERATURES FROM THE MID 20S NORTH TO LOWER
30S SOUTHEAST TOWARD SUNRISE THU LOOKED REASONABLE WITH ONLY MINOR
ADJUSTMENTS MADE.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED MAR 25 2015

CONTINUED CHALLENGES IN THE LONGER RANGE WITH GENERALLY ACTIVE
REGIME...AND LOWER CONFIDENCE IN THE DETAILS.  THUS FAVORED A MODEL
BLEND THROUGH THE PERIOD.

WITH THE UPPER RIDGE DOMINATING THE WESTERN US INTO NEXT WEEK...THE
MIDWEST WILL REMAIN IN NORTHWEST FLOW THROUGH THE PERIOD.  NET
RESULT WILL BE A SERIES OF WAVES TRAVERSING THE REGION APPROXIMATELY
EVERY THIRD DAY.  THIS IS WHERE THE CERTAINTY RAPIDLY DIMINISHES.
AS IS TYPICAL DURING THE TRANSITION SEASONS AND IN FAST NORTHWEST
FLOW...MODEL HANDLING OF THE TRACK...TIMING...AND STRENGTH OF
INDIVIDUAL WAVES VARIES WIDELY FROM MODEL TO MODEL AND RUN TO RUN.
THUS CONFIDENCE IS LOW ON THE PARTICULAR IMPACT OF SPECIFIC SYSTEMS
ON THE LOCAL CWA THROUGH THE LONGER TERM.

THURSDAY...A WEAK SHORT WAVE IS EXPECTED TO DROP OUT OF WI...GRAZING
THE FAR EASTERN PART OF THE CWFA. BY FRIDAY BOTH SURFACE AND UPPER
RIDGING ARE PROGGED TO TAKE HOLD AND CYCLONIC FLOW ALOFT SHIFTS EAST
OF THE MS RIVER.

AS WE MOVE INTO THE WEEKEND...CONFIDENCE TAKES AS MAJOR DIVE FOR THE
REASONS MENTIONED ABOVE.  HOWEVER...CURRENT MODEL BLEND TIMING
SUGGESTS A STRONGER SHORT WAVE BUSTING INTO THE UPPER RIDGE IN THE
SATURDAY NIGHT TO SUNDAY TIME FRAME WITH STRONG WAA SATURDAY AND
SATURDAY NIGHT AHEAD OF THE ASSOCIATED COLD FRONT. WITH MOST
MODELS SHOWING THE GULF CUT OFF...LOOKS LIKE MOISTURE AVAILABILITY
WILL BE IN QUESTION FOR THIS NEXT ROUND OVER THE WEEKEND SO LOW
POPS WILL BE THE BEST WE CAN DO FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1259 PM CDT WED MAR 25 2015

IFR CIGS SLOW TO IMPROVE TODAY...BUT INCREASING WEST TO NORTHWEST
LLVL FLOW WILL CONTINUE TO HELP LIFT CIGS TO MVFR FROM WEST TO
EAST. UPSTREAM CLEARING HOLES HAVE DIURNALLY RE-FILLED WITH MVFR
BKN CU...AND WILL TREND THAT WAY FOR MOST OF THE TAFS THRU LATE
AFTERNOON. WILL SCATTER OUT OR RAISE A BKN DECK TO LOW VFR LEVELS AT
DBQ/CID/MLI THIS EVENING...BUT SOME CONCERN THAT THE MVFR BKN DECK
TO STAY TRAPPED IN FOR MUCH OF THE EVENING INTO THE OVERNIGHT. AT
BRL...OVERRUNNING LIGHT RAIN/ SPRINKLES EVENT APPROACHING FROM THE
WEST WILL HAVE TROUBLE AS IT ENCOUNTERS DRY AIR THIS AFTERNOON...
BUT WILL KEEP MVFR CIGS GOING THERE WELL INTO THE EVENING. SOME
BETTER SUPPORT FOR LIGHT RAIN AT BRL FROM 7 PM CDT THROUGH 9PM...
BEFORE IT SLIDES OFF TO THE SOUTHEAST. WEST SFC WINDS TO VEER MORE
NORTHWESTERLY BY MID EVENING ACRS THE ENTIRE AREA. EVEN THE LOW
VFR CIGS OR LINGERING MVFR CIGS PROGGED TO CLEAR OUT TOWARD
SUNRISE THU MORNING.  ..12..

&&

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

$$

SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...DMD
AVIATION...12






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