000
FXUS63 KDVN 030911
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
311 AM CST TUE MAR 3 2015

.SYNOPSIS...
ISSUED AT 252 AM CST TUE MAR 3 2015

STRONG WARM ADVECTION PAIRED WITH LIFT FROM A 120 KT JET STREAK
JUST NORTH OF OUR CWA IS PROVIDING A BAND OF MODERATE TO LOCALLY
HEAVY PRECIPITATION FROM SOUTHWEST IOWA THROUGH NORTHWEST
ILLINOIS. THIS BAND BISECT OUR CWA...AND HAS HEAVY DENDRITIC SNOW
FOUND NORTH OF INTERSTATE 80...WITH SNOW AND SLEET MIX NEAR
INTERSTATE 80...AND FREEZING RAIN FARTHER SOUTH. THIS WILD SWING
IN PCPN TYPES WAS EXPECTED...YET IS PERSONALLY AMAZING TO WATCH
TAKE PLACE OUT THE WINDOW OF AN OFFICE AT NIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CST TUE MAR 3 2015

THE MAIN AXIS OF PCPN APPEARS BEST HANDLED BY THE RAP AND
HRRR...WHICH ARE BOTH FARTHER NORTH THAN THE GFS. IF THERE IS A
SYNOPTIC SCALE MODEL HANDLING THIS WELL...THE GEM SEEMS ACCURATE
ENOUGH. SO...WITH FRONTOGENETICAL FORCING SHOWING ITS HAND ON
RADAR...WE WILL SEE A BAND OF MODERATE AMOUNTS TAKE PLACE THROUGH
15Z...POSSIBLY 16Z...BEFORE ENDING AND SHIFTING NORTHEAST. WITHIN
THIS EVENT...LOCATIONS JUST NORTH OF INTERSTATE 80 MAY SEE AROUND
2 INCHES OF SNOW...BEFORE MIXING WITH SLEET OR FREEZING RAIN AND
ENDING THIS MORNING. ALONG INTERSTATE 80...INCLUDING THE QUAD
CITIES...AND IOWA CITY...WE WILL LIKELY WAFFLE BACK AND FORTH
THROUGH 6 AM BETWEEN LARGE FLAKES AND SLEET...WITH ANY LIGHT PCPN
FALLING AND FREEZING RAIN. A SLIPPERY MIX NO DOUBT. FARTHER
SOUTH...IT APPEARS MOST OF THE MORE INTENSE BAND OF FREEZING RAINS
HAVE SHIFTED NORTH AS THE MESOSCALE BAND SOLIDIFIED.
HOWEVER...SOME SHOWERS OF FREEZING RAIN CAN STILL BE EXPECTED
THROUGH 8 AM...AS TEMPERATURES RISE ABOVE FREEZING. ELSEWHERE...AS
THE MIX ENDS...TEMPERATURES SHOULD RESPOND MORE QUICKLY IN THE
SOUTH WINDS AND MIXING OF DAYTIME HOURS. HIGHS SHOULD STILL REACH
THE MID TO UPPER 30S IN MOST SPOTS. BY NOON...ONLY PATCHY
FLURRIES...SPRINKLES OR DRIZZLE IS EXPECTED. THUS...A DRY AND
BREEZY AFTERNOON SHOULD BE WIDESPREAD...WITH COLD ADVECTION REALLY
KICKING IN BY EVENING. TEMPERATURES TONIGHT WILL FALL TO THE LOWER
SINGLE DIGIT NORTHWEST TO AROUND 10 SOUTHEAST. THERE IS NO DOUBT
THAT SPRING AIR CAME CLOSE TO OUR CWA TODAY...BUT IT LOST THE
BATTLE.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 252 AM CST TUE MAR 3 2015

MAIN FORECAST CONCERN FOR THE EXTENDED ARE THE WIND CHILLS FOR
MIDWEEK.  COLD AIR SURGING IN BEHIND THE SYSTEM ON TUESDAY LOOKS TO
GIVE US ANOTHER SHOT OF VERY COLD AIR.  THIS WILL LEAD TO WIND
CHILLS BETWEEN 20 AND 30 BELOW ZERO.  AFTER THIS IT APPEARS AS
THOUGH WARMER TEMPERATURES ARE FINALLY IN THE FORECAST!

AN ARCTIC HIGH PRESSURE WILL SLIDE INTO THE AREA AT THE BEGINNING OF
THE PERIOD.  ON THURSDAY MORNING IT WILL BE DIRECTLY OVER US.  THIS
WILL LEAD TO CLEAR SKIES AND VERY UNSEASONABLE LOW TEMPERATURES.
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH COLD TEMPERATURES ON
THURSDAY AM.  EVEN THOUGH WINDS WILL BE LIGHT...DUE TO THE HIGH
PRESSURE...ANY WIND WITH THOSE LOW TEMPERATURES WILL LEAD TO WIND
CHILLS THAT WILL REACH WIND CHILL CRITERIA.

NOW TO THE MORE HAPPY NEWS...A PATTERN SHIFT LOOKS MORE LIKELY.
MODELS SHOW THAT THE FLOW BECOMES MORE ZONAL AND THE TRAJECTORIES OF
THE AIR MOVING INTO OUR AREA LOOKS TO BE MORE OFF OF THE CONTINENTAL
US.  THIS MEANS WARMER...MORE AVERAGE TEMPERATURES THIS WEEKEND AND
INTO NEXT WEEK.  THE EURO IS ESPECIALLY WARM FOR JUST OUT OF THIS
FORECAST PERIOD.  THE EVEN BETTER NEWS IS THAT THE ENSEMBLE
AVERAGE...GFS AND ECMWF H5 FLOW IS CLOSE TO EACH OTHER AT THE END OF
THE FORECAST PERIOD.  THIS LEADS ME TO HAVE HIGHER THAN AVERAGE
CONFIDENCE ON A WARM UP NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1147 PM CST MON MAR 2 2015

LOW LEVEL WIND SHEAR IS STILL POSSIBLE OVERNIGHT INTO EARLY
TUESDAY AM WITH STRENGTHENING LOW LEVEL JET. MODELS THOUGH VARY ON
STRENGTH OF WINDS 1500-2000 FT AGL (30-40 KTS) AND WITH EXPECTED
INCREASE IN SURFACE WINDS WITH SOME GUSTS HAVE CONTINUED TO LEAVE
OUT MENTION ATTIM BUT CONTINUE TO MONITOR. OTHERWISE... OVERNIGHT
AND TUESDAY AM EXPECT CONDITIONS TO DETERIORATE INTO MVFR TO
POSSIBLY AREAS OF IFR WITH A SHOWERY WINTRY MIX OF PCPN ACROSS THE
AREA. PCPN WILL BE MAINLY LIGHT WITH TYPES FAVORING MAINLY SLEET/
SNOW NORTH OF I-80 WITH FREEZING RAIN/SLEET TRANSITION TO RAIN
SOUTH WHERE MINOR GLAZING OF ICE ACCUM POSSIBLE. PCPN TO DIMINISH
IN COVERAGE BY LATE AM THROUGH MIDDAY WITH MVFR TO POSSIBLY AREAS
OF IFR CONDITIONS CONTINUING THROUGH AFTN AHEAD OF A COLD FRONT
WHICH WILL PASS THROUGH THE TERMINALS 19-23Z AND MAY BE
ACCOMPANIED BY FLURRIES OR BRIEF PERIOD OF LIGHT SNOW ESPECIALLY
NORTHEAST IA.


&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR BENTON-BUCHANAN-
     CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-
     KEOKUK-LINN-LOUISA-MUSCATINE-SCOTT-WASHINGTON.

     WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR DES
     MOINES-HENRY IA-JEFFERSON-LEE-VAN BUREN.

IL...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR BUREAU-CARROLL-
     HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-
     WHITESIDE.

     WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR HANCOCK-
     HENDERSON-MCDONOUGH-WARREN.

MO...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR CLARK-
     SCOTLAND.

&&

$$

SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...GIBBS
AVIATION...05