Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 011713
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1113 AM CST SUN MAR 1 2015

.UPDATE...
ISSUED AT 637 AM CST SUN MAR 1 2015

OVERALL A FEW SMALL TWEAKS TO THE FORECAST WERE MADE. RADAR
RETURNS SUGGEST THAT SNOW BAND COULD SHIFT A LITTLE FURTHER NORTH
TODAY. AS SUCH INCREASED POPS FURTHER NORTH OF WHERE THEY WERE
BEFORE. TOTAL SNOWFALL AMOUNTS REMAIN THE SAME AS EARLIER. SOME
PATCHY DENSE FOG HAS DEVELOPED ACROSS THE AREA. THIS SEEMS TO BE
LIMITED TO THE MISSISSIPPI RIVER VALLEY. THE FOG SHOULD BURN OFF
THIS AM. OTHER THAN THAT FORECAST LOOKS TO BE ON TRACK.

&&

.SYNOPSIS...
ISSUED AT 149 AM CST SUN MAR 1 2015

VERY MINOR SNOWFALL ACCUMULATIONS YESTERDAY WERE
REPORTED...ESPECIALLY SOUTH OF INTERSTATE 80. REGIONAL RADAR THIS
MORNING DEPICTS MOST OF THE SNOW SOUTH AND EAST OF OUR AREA. WITH
LIGHT FLURRIES FALLING ACROSS THE CWA. SATELLITE AND ASOS STATIONS
REPORTED LOW CLOUDS MOVING THROUGH IA AND TOWARDS OUR AREA. THIS
SHOULD HELP TO WARM TEMPS OVERNIGHT AND ALLEVIATE POSSIBLE DENSE
FOG.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 149 AM CST SUN MAR 1 2015

MAIN FORECAST CONCERN FOR THE SHORT TERM ARE THE CHANCES OF SNOW
TODAY AS A SECOND WAVE TRANSVERSES THE FLOW. CHANCES ARE LOW FOR
ACCUMULATING SNOW EXCEPT FOR FAR SOUTHERN AREAS OF THE CWA. TOTAL
SNOWFALL TODAY SHOULD BE LESS THAN AN INCH OVERALL.

A SHORTWAVE EMBEDDED IN THE DEEPER TROF WAS LOCATED OVER W KS AND
SW NE. THIS VORT IS QUICKLY ADVECTING THROUGH THE FLOW TOWARDS THE
AREA. SINCE MOST OF THE VORT IS PARALLEL TO THE FLOW...OVERALL
HEIGHT FALLS AND SUBSEQUENT FORCING WILL BE WEAK AND LIMITED TO A
SMALL AREA. THE MAJORITY OF RUNS TAKES THIS OVER FAR SOUTHERN
PORTIONS OF THE CWA. THIS ALONG WITH HRRR AND WRFARW AND WRFNMM
MODEL REFLECTIVITY...SUGGEST THAT OVERALL ADDITIONAL SNOW WILL BE
LIGHT AND LIMITED TO FAR SOUTHERN AREAS OF THE CWA. CURRENT RADAR
SUGGESTS THAT MOST OF THE SNOW WILL LIKELY AFFECT FAR SE ZONES AND
CITIES LIKE MQB. HPC QPF SEEMS TO BE OVERDONE FOR THE NEXT 12
HOURS...AS SUCH LOWERED THE QPF. THIS GIVES MQB ANOTHER 0.6 INCHES
OF SNOW TODAY. BELIEVE THAT MOST OF THE PRECIP WILL BE OUT OF THE
CWA BY 18Z.

AS FAR AS TEMPS...WE STILL END UP WITH BELOW AVERAGE TEMPS. WENT
WITH RAWBLEND FOR THE HIGHS TODAY. CLOUDS SHOULD CLEAR AND WE
SHOULD END UP WITH SUN FOR THE SUNSET.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 149 AM CST SUN MAR 1 2015

THE MAIN ISSUE IN THE EXTENDED WILL BE THE MIXED PCPN TYPE EVENT
MONDAY NIGHT INTO TUESDAY. THIS EVENT IS LIKELY TO CONTAIN A FULL
SHIFT FROM LIGHT SNOW TO MODERATE SNOW...TO SLEET...TO FREEZING
RAIN...TO RAIN...THEN FINALLY A LIGHT MIX OF RAIN AND SNOW BEFORE
ENDING. WHILE THIS SOUNDS RATHER SCARY AT FACE VALUE WITH RESPECT TO
HAZARDS...IT APPEARS THE TRANSITION FROM SNOW TO FREEZING TO RAIN
SHOULD BE A QUICK ONE DURING THE 3 AM TUESDAY TO 9 AM TUESDAY
PERIOD. THUS...ACCUMULATIONS OF ICING WILL BE LIMITED AND ARE MOST
LIKELY GOING TO WARRANT AN ADVISORY VS A WARNING.

SNOW SHOULD BEGIN TO BECOME WIDESPREAD AFTER MIDNIGHT MONDAY
NIGHT...SO WILL BEGIN TO RAMP UP POPS TO LIKELY AT THAT TIME. THE
INITIAL PHASE OF PCPN SHOULD BE SNOW AT ANY LOCATION...AND WITH
WIDESPREAD ACTIVITY SPREADING NORTHWARD AROUND 3 AM...WE SHOULD SEE
AN INCH OR TWO OF SNOW ACCUMULATION OVER THE NORTHERN 1/2 TO 2/3RD.
IN THIS TIME TIME FRAME...THE SOUTH WILL BEGIN TO WARM
ALOFT...RESULTING IN SLEET MIXING IN WITH SNOW...THEN CHANGING TO A
LIGHT MIX OF FREEZING RAIN AND SLEET TOWARD 6 AM. THUS...IT APPEARS
THAT A LIKELY ADVISORY WOULD BEGIN NO EARLIER THAN 06Z...AND COULD
HOLD OFF TIL 3 AM. THE FREEZING RAIN THREAT SHOULD SPREAD
NORTH...ALL THE WAY UP TO AROUND HIGHWAY 20 BY TUESDAY MORNING
AROUND 9 AM...HOWEVER...IN ANY ONE LOCATION...THE GRADUAL RISE IN
TEMPERATURES AND DEWPOINTS SHOULD LIMIT THE DURATION OF FREEZING
RAIN TO AROUND 5 HOURS OR LESS...AND IN THE NORTH...WHERE
TEMPERATURES REMAIN NEAR FREEZING THE LONGEST...THE WINDOW IS
FURTHER LIMITED BY ANY RAIN CHANGING BACK TO SNOW BY EARLY
AFTERNOON. THUS...I FORESEE AN ADVISORY RUNNING FROM LATE MONDAY
NIGHT THROUGH NOON TUESDAY...BUT THIS IS TOO EARLY TO ISSUE ON A
MARGINAL EVENT...AND WILL EXPECT TO SEE THIS COME OUT ON FUTURE
SHIFTS TODAY OR TONIGHT.

SNOW ON THE BACKSIDE OF THE COLD FRONT TUESDAY AFTERNOON APPEARS
VERY LIGHT...AS DRY AIR AGGRESSIVELY SWEEPS IN FROM THE WEST. IN
FACT...I HAVE REMOVED POPS TUESDAY NIGHT ALL TOGETHER...AND LOWERED
AFTERNOON TO CHANCE AREA WIDE.  QPF OVER THE ENTIRE EVENT APPEARS
TO BE IN THE 0.20 TO 0.50 RANGE...WITH SOME LOCALIZED HIGHER
AMOUNTS THROUGH SHOWERS IN THE MID MORNING HOURS. WHILE TEMPERATURES
TUESDAY SHOULD SURGE ABOVE FREEZING...THIS WILL NOT REMOVE OUR SNOW
PACK...AND ANY RAIN WILL BE ABSORBED INTO THIS SNOW PACK...SO NO
RUNOFF ISSUES ARE EXPECTED.

AFTER OUR BRIEF WARM UP TUESDAY...THE COLD WILL BE BACK FOR TUESDAY
NIGHT THROUGH THURSDAY NIGHT. OUR FORECAST IS CONFIDENTLY DRY...AND
COLD AS THE GUIDANCE BLEND INITIALIZED WITH.   FRIDAY STILL
INDICATES A TRANSITION TO MORE ZONAL FLOW...AND WITH A CLIPPER
EXPECTED TO PASS TO THE NORTH OF IOWA...WE SHOULD BE WARM
SECTORED...AND SEE TWO RELATIVELY MILD DAYS( 30S TO LOWER 40S) FRIDAY
AND SATURDAY.

ERVIN

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1109 AM CST SUN MAR 1 2015

VFR CONDITIONS FOR AT LEAST THE NEXT 24 HOURS. ANOTHER ARCTIC HIGH
PRESSURE SYSTEM WILL MOVE IN FROM THE NORTHERN PLAINS. SKIES WILL
CONTINUE TO CLEAR THIS AFTERNOON WITH LIGHT SOUTHWEST WINDS SHIFTING
TO THE NORTHWEST AT 5 TO 10 KTS BY DUSK...CONTINUING THEN INTO MID
DAY MONDAY.

&&

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

&&

$$

UPDATE...GIBBS
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...ERVIN
AVIATION...NICHOLS





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