Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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979
FXUS63 KDVN 041120
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
520 AM CST THU FEB 4 2016

...AVIATION UPDATE...

.SYNOPSIS...
ISSUED AT 309 AM CST THU FEB 4 2016

AT 08Z...SATELLITE FOG CHANNEL SHOWED THE BACK EDGE OF THE STRATUS
BEHIND THE DEPARTING STORM OVER SE WI AND NE IL...EAST OF THE
FORECAST AREA. THIS WAS LEAVING CLEAR SKIES UNDER A WEAK
TRANSITORY RIDGE WITH TEMPERATURES IN THE SINGLE DIGITS OVER THE
DEEPEST SNOW COVER ALONG THE HIGHWAY 20 CORRIDOR WITH MAINLY TEENS
ELSEWHERE. A SHORTWAVE IN NW FLOW ALOFT WAS PRODUCING A WEAK
CLIPPER SYSTEM WITH LOW PRESSURE CENTERED OVER NW MN AND WEAK
FRONTAL BOUNDARIES REACHING SOUTH AND SW. A BAND OF MID LEVEL
CLOUDS IN ITS WARM ADVECTION BAND WAS APPROACHING THE FORECAST
AREA FROM SOUTHERN MN AND NW IA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CST THU FEB 4 2016

THE CLIPPER SYSTEM WILL PASS TO THE NORTHEAST TODAY WITH ITS
ASSOCIATED FRONTAL BOUNDARIES PASSING THROUGH THE AREA TODAY AND
THIS EVENING. THIS WILL RESULT IN WIND SHIFTS AND A PERIOD OF MID
AND HIGH LEVEL CLOUD COVER AS THE STRONGER FORCING PASSES WELL TO
THE NORTH. SOME HIGH RES MODELS SUGGEST A ROUND OF LIGHT SNOW OR
FLURRIES IN THE FAR NORTH AND NORTHEAST FROM MID AFTERNOON INTO
EARLY EVENING. HOWEVER...WITH ONLY MODEST FORCING AND LIMITED
MOISTURE...WILL LEAVE THE MENTION OF FLURRIES OUT OF THE FORECAST
FOR NOW. DEVELOPING SW WINDS IN THE WARM SECTOR SHOULD PUSH
TEMPERATURES INTO THE MID AND UPPER 30S OVER THE SNOWFREE CENTRAL
AND SOUTHERN HALF OF THE FORECAST AREA. FURTHER NORTH...THE FRESH
SNOW AND LIKELIHOOD OF THICKER CLOUD COVER WAS LIMITING MODEL
FORECAST HIGHS TO THE UPPER 20S...WHICH LOOKS REASONABLE.

TONIGHT...THE WEAK FRONT AND PERIOD OF POTENTIAL FLURRIES WILL BE
PUSHING THROUGH IN THE EVENING. THIS IS FOLLOWED BY A SHORTWAVE
RIDGE AXIS AND PASSING SURFACE HIGH AHEAD OF THE NEXT CLIPPER SYSTEM
ARRIVING FRIDAY. THE ECMWF IS ALONE GENERATING AN AXIS OF QPF OVER
NW IL IN THE EVENING WITH THE PASSING COLD FRONT AND UPPER LEVEL
SHORTWAVE...WHILE THE OTHER MODELS HAVE WEAKER FORCING AND NO
RESULTING PRECIPITATION. WHILE WORTH KEEPING AN EYE ON...WILL
MAINTAIN A DRY FORECAST WITH THE FROPA FOR NOW. CLOUD COVER WILL
LIKELY THIN OVERNIGHT ALLOWING TEMPERATURES TO DROP INTO THE TEENS
TO LOWER 20S WITH LIGHT NW WINDS AND COLDEST READINGS OVER THE
SNOWFIELDS ACROSS THE NW AND FAR NORTH.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 309 AM CST THU FEB 4 2016

MAIN FORECAST CONCERN FOR THE LONG TERM IS THE CLIPPER LATE ON THE
DAY FRIDAY AND THEN THE COLD DUMP AND CLIPPER SET UP FOR EARLY NEXT
WEEK.  LITTLE TO NO SNOW ACCUMULATION IS EXPECTED FOR THE CLIPPER
FRIDAY.  NEXT WEEK STILL LOOKS TO BE COLD WITH THE COLD BEING
CONSISTENT IN THE GUIDANCE.

FRIDAY EVENING...A CLIPPER WILL APPROACH THE AREA BY 00Z SAT.  HIRES
NMM DEPICTS AN AREA OF SNOW ACROSS CENTRAL IOWA MOVING THIS WAY.
WITH DRY LOW LEVELS...THE COLUMN WILL NEED TO SATURATE BEFORE WE SEE
MUCH SNOW ACROSS THE AREA.  AT THIS TIME IT STILL LOOKS AS THOUGH
THE FORCING DOES NOT INTERSECT LONG WITH THE COMPLETE SATURATION OF
THE COLUMN.  MODEL SOUNDINGS SHOW MAYBE AN HOUR OR TWO OF LIGHT SNOW
FRIDAY...ESPECIALLY ALONG THE HIGHWAY 20 CORRIDOR AND NORTH.  AS
SUCH STILL MAINTAINING A SCHC POPS WITH SNOW ACCUM AMOUNTS OF A
LITTLE MORE THAN 0.1 INCHES

THIS WEEKEND...THE WELL DISCUSSED WARMUP IS STILL FORECAST WITH
TEMPERATURES WELL INTO THE 30S AND EVEN THE 40S ACROSS THE SOUTH. IT
APPEARS THAT THE GFS AND GEM ARE TOO COLD WITH SFC TEMPS.  THIS IS
LIKELY DUE TO THE SNOW COVER THAT THE MODELS HAVE.  AS SUCH TRIED TO
LEAN AWAY FROM THESE MODELS WHEN LOOKING AT HIGH TEMPS FOR SAT AND
SUN.  SUNDAY...THE NEXT CLIPPER AND A SFC LOW IMPINGE ON THE AREA.
WITH THE THERMAL PROFILE BEING WELL ABOVE FREEZING IT LOOKS AS
THOUGH THERE IS A SCHC FOR RAIN BEFORE THE COLD AIR COMES IN AND
TURNS ANY PRECIP TO SNOW.  A SERIES OF CLIPPERS ON THE COLD WILL
AFFECT THE AREA LEADING TO LOW CHC POPS ACROSS THE CWA THROUGH AT
LEAST TUESDAY.

H85 TEMPS DURING NEXT WEEK APPEAR TO BE CLOSER IN AGREEMENT WITH THE
GFS BEGINNING TO TREND TOWARDS THE ECMWF.  THE GFS HAS H85 TEMPS NEAR
-20C WHEREAS THE ECMWF HAS TEMPS NEAR -15C.  REGARDLESS A FEW NIGHTS
WILL HAVE LOWS NEAR OR BELOW ZERO.  WIND CHILLS EARLY NEXT WEEK MAY
REACH ADVISORY LEVELS.  THIS WILL NEED TO BE WATCHED THROUGH THE
NEXT FEW DAYS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 520 AM CST THU FEB 4 2016

VFR CONDITIONS WILL PREVAIL THROUGHOUT. A WEAK SYSTEM MOVING
THROUGH THE NORTHERN PLAINS INTO THE GREAT LAKES WILL PROVIDE
MAINLY A WIND SHIFT AND PERIOD OF MID AND HIGH LEVEL CLOUDS.
THERE IS A POSSIBILITY THAT THE WEAK COLD FRONT MOVING THROUGH
FROM MID AFTERNOON THROUGH EARLY EVENING MAY RESULT IN
FLURRIES...ESPECIALLY AT DBQ AND MLI. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS TOO LOW TO INCLUDE IN THE FORECASTS AT THIS TIME.

&&

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

$$

SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...GIBBS
AVIATION...SHEETS



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