000
FXUS63 KDVN 150449
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1149 PM CDT FRI MAR 14 2014

.UPDATE...
ISSUED AT 821 PM CDT FRI MAR 14 2014

ICE JAMS ALONG THE ROCK RIVER AT MOLINE NECESSITATED THE ISSUANCE
OF A FLOOD WATCH FOR ROCK ISLAND AND HENRY COUNTIES. ITS DIFFICULT
TO TELL AT THIS POINT HOW LONG THE ICE JAM THREAT WILL LAST. THE
WATCH RUNS THROUGH 7PM SATURDAY AND WILL BE ADJUSTED AS NEW
INFORMATION COMES IN ON THE ICE CONDITIONS ALONG THE ROCK RIVER.

&&

.SYNOPSIS...
ISSUED AT 236 PM CDT FRI MAR 14 2014

TYPICAL WINDY AND MILD MARCH WEATHER WAS IN PLACE THIS AFTERNOON
ACROSS THE FORECAST AREA. AT 2 PM...THE SURFACE COLD FRONT WAS
ROUGHLY FROM CHICAGO TO ST LOUIS. DEEP MIXING AND SUBSIDENCE BEHIND
THE FRONT HAS ALLOWED TEMPERATURES TO WARM INTO THE MID AND UPPER
50S SOUTH OF I-80...WHILE DEVELOPING STRATO CU...STRONGER COLD AIR
ADVECTION...AND PATCHY SNOW COVER WAS LIMITING THE HIGHWAY 20
CORRIDOR TO THE LOWER 40S. THE COLD FRONT WAS ASSOCIATED WITH A
SURFACE LOW OVER EASTERN UPPER MI...WHICH HAD A WEAK TROUGH AXIS
REACHING EAST ACROSS NORTHERN WI INTO CENTRAL MN. ALOFT...A STRONG
SHORTWAVE WAS MOVING INTO THE GREAT LAKES WITH AN UPSTREAM RIDGE
AXIS OVER THE NORTHERN ROCKIES. THE NEXT SHORTWAVE POISED TO AFFECT
THE REGION THIS WEEKEND WAS EVIDENT ON WV IMAGES MOVING INTO THE
PACIFIC NW.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 236 PM CDT FRI MAR 14 2014

INITIAL FOCUS IS TEMPERATURES TODAY INTO EARLY SATURDAY...THEN
DEVELOPING PRECIPITATION AS THE ENERGY MOVING INTO THE NW LEADS TO
CYCLOGENESIS OVER THE PLAINS. TONIGHT...INCOMING CLOUD COVER OVER N
CENTRAL IA INTO MN AND EASTERN SD IS LOOKING MORE INSTABILITY DRIVEN
IN TIME AND SHOULD AFFECT MAINLY THE NORTHERN HALF OF THE FORECAST
AREA BEFORE DISSIPATING THIS EVENING...AS INDICATED BY SHORT TERM
MODEL LOW LEVEL RH TRENDS. THIS PROCESS WILL BE HELPED ALONG BY MID
LEVEL SUBSIDENCE AHEAD OF THE UPPER RIDGE OVER THE ROCKIES. AT THE
SURFACE...HIGH PRESSURE IS ANCHORED WELL TO THE NORTH OVER CENTRAL
CANADA...LEADING TO A COL TYPE REGION OVER THE FORECAST AREA TONIGHT
AS THE LOW CONTINUES WESTWARD. THIS COMBINATION OF CLEARING SKIES
AND LIGHT WINDS SHOULD ALLOW TEMPERATURES TO DROP BELOW FREEZING
OVER MOST OF THE FORECAST AREA. LOOKING AT VERIFICATION FROM THE
SOURCE REGION THIS MORNING...WILL HAVE COLDEST VALUES IN THE MID 20S
CLOSEST TO THE LAST OF THE REMAINING SNOW IN THE FAR NORTH AND EAST
WITH UPPER 20S TO LOWER 30S ELSEWHERE.

SATURDAY...THE SHORTWAVE MOVING INTO THE NW U.S. IS EXPECTED TO
EMERGE INTO THE PLAINS...WHERE IT BEGINS TO PHASE WITH A SEPARATE
SOUTHERN STREAM LOW CURRENTLY OVER AZ. THIS LEADS TO THE DEVELOPMENT
OF SURFACE LOW OVER THE CENTRAL PLAINS AND FORMATION OF A WARM FRONT
AND TIGHT BAROCLINIC AXIS AT 850 MB OVER SOUTHERN IA INTO CENTRAL IL
SATURDAY AFTERNOON. SOUTH OF THIS BOUNDARY ...SOUTH TO SOUTHEAST
WINDS AND SUNSHINE SHOULD LEAD TO ANOTHER MILD DAY WITH HIGHS IN THE
50S TO NEAR 60 ALONG AND SOUTH OF THE HIGHWAY 34 CORRIDOR. TO THE
NORTH...THE FRONTOGENESIS AND HIGH PRESSURE SINKING SOUTH OUT OF
CANADA WILL LEAD TO EAST TO NORTHEAST WINDS. THIS ALONG WITH
THICKENING CLOUD COVER IN THE WARM AIR ADVECTION ALOFT WILL LIMIT HIGHS
TO THE UPPER 30S TO UPPER 40S OVER THE CENTRAL AND NORTHERN FORECAST
AREA. WITH THIS LOW LEVEL COOL DRY AIR...MID LEVEL CONFLUENT FLOW
ALOFT AND MORE FAVORABLE JET PLACEMENT FURTHER NORTH...MODEL QPF
PLACEMENT INTO THE NORTHERN PORTIONS OF THE FORECAST AREA LOOKS
OVERDONE. WILL INCLUDE LOW CHANCE POPS ACROSS THE FAR NORTH AND WEST
FOR LATE AFTERNOON...BUT  BETTER CHANCES FOR PRECIPITATION WILL HOLD
OFF UNTIL SATURDAY NIGHT. MODEL FORECAST SOUNDINGS GENERALLY SUPPORT ALL
PRECIPITATION IN THE FORM OF SNOW IF IT DOES DEVELOP IN THE NORTH
WITH A WET SNOW/RAIN MIX CENTRAL AND WEST IF IT WERE TO DEVELOP IN
THE AFTERNOON.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 236 PM CDT FRI MAR 14 2014

GENERALLY DRY AND MOSTLY SEASONABLE TEMPS FOR MID MARCH WITH SOME LIGHT
SNOW OR FLURRIES POSSIBLE SATURDAY NIGHT INTO EARLY SUNDAY.

OVERVIEW...INITIALIZATION AND VERIFICATION SLIGHTLY BETTER TODAY WITH
GOOD CONSISTENCY ON LARGE SCALE ISSUES. THE AMERICAN SOLUTIONS CONTINUE
A SLIGHT TOO MOIST BL. THIS CONSISTENT BIAS HAS BEEN ACCOUNTED FOR
A COUPLE OF DAYS IN THE FORECAST. AMERICAN SOLUTIONS AND TOO A LESSER
EXTENT OTHERS HAVE LOWERED THEIR SATURDAY QPF AMOUNTS BY 50-80 PERCENT
THE PAST 24-48 HOURS. A SLIGHTLY DRIER EVENT THAN SOLUTIONS INDICATE
IS SUGGESTED BEFORE THE EVENT OCCURS ON LATE SATURDAY PM AND SATURDAY
NIGHT. VERIFICATION AND RUN TO RUN CONTINUITY SHOWS MINOR SENSIBLE
WEATHER DIFFERENCES WITH A 70/30 MIX OF GFS TO HI-RES ECMWF/GEM-NH
MOST FAVORED FIT.

SATURDAY NIGHT...LIMITED FORCING AND MOISTURE SUPPORTS A 2 TO 5 HOUR
BAND OF LIGHT PRECIPITATION TO SLIDE SE ACROSS THE FORECAST AREA. THERMAL
PROFILES SUGGEST GOOD EVAPORATIVE COOLING WITH SIGNIFICANT CAA ALOFT.
THIS PROVIDES GOOD CONFIDENCE THAT PRECIPITATION MAY START AS RAIN TO
TRANSITION TO SNOW WITHIN 1 TO AT MOST 2 HOURS OF STARTING. A BRIEF
PERIOD OF SLEET IS QUITE POSSIBLE FOR LATER SHIFTS TO CONSIDER. HAVE
TRIED TO HAVE A PERIOD OF RAIN/SNOW CHANGING TO SNOW. SNOW TOTALS ARE
AOB .5" TO LOCALLY NEAR 1 INCH NORTH OF I-80 CORRIDOR. MINS ARE GENERALLY
15 TO 25 WITH NORTH COLDER AS PARTIAL CLEARING OCCURS. BLUSTERY WINDS
OF 15 TO 25 MPH AND SOME GUSTS TO NEAR 30 MPH STILL ON TRACK.

SUNDAY...SKIES TO BECOME MOSTLY SUNNY WITH LINGERING LIGHT SNOW OR FLURRIES
TO END BY MOVING TO THE SOUTH LATE MORNING. HIGHS...MINOR CHANGES MADE
WITH UPPER 20S NORTH TO LOWER TO MID 30S SOUTH. GUSTY NE WINDS OF 15
TO 30 MPH TO DIMINISH TOWARD LATE AFTERNOON. SUNDAY...COLD FOR MID MARCH
WITH LIGHT NE WINDS SUPPORTIVE OF VERY COLD IN LOW LYING LOCATIONS IN
THE WAPSI AND ROCK RIVER VALLEY/S. LOWS IN THE TEENS WITH SOME ISOLATED
VALUES NEAR 10F POSSIBLE NORTH OF I-80 FOR LATER SHIFTS TO REASSESS.

MONDAY AND TUESDAY...SURFACE HIGH TO MOVE EAST WITH WARMING TREND WITH
HIGHS ABOUT 35 TO 43 ON MONDAY AND ABOUT 10 DEGREES WARMER ON TUESDAY.
LIMITED MOISTURE SUPPORTS ONLY LOW TO VERY LOW POPS TUESDAY WITH NEXT
UPPER DISTURBANCE AS GULF MOISTURE CLOSED AND LOW TRACK TO PASS TO NW
OR OVER FAR NW WHICH NOT FAVORABLE FOR ANY RAIN OR SNOW. WINDS MAY BECOME
GUSTY TUESDAY AHEAD OF NEXT SHORT WAVE. IF THIS SYSTEM SLOWS DOWN BY
6+ HOURS ALLOWING FOR MORE MOISTURE OR TRACKS FURTHER SE THEN HIGHER
POPS MAY NEED TO BE ADDED. LOWS SHOULD STAY AROUND FREEZING.

WEDNESDAY THROUGH FRIDAY...ANY PRECIPITATION TO END BY MID DAY WEDNESDAY
WITH ZONAL FLOW SUPPORTING TEMPERATURES AT OR ABOVE NORMAL WITH A WARMING
TREND THU/FRI. SOME LOCAL TOOLS BASED ON 850 TEMPS SUGGEST HIGHER TEMPS
BY 5 TO 8+ DEGREES FOR LATER SHIFTS TO REASSESS. SOME HIGHS IN THE 60S
ARE NOT UNREASONABLE IF TRENDS CONTINUE. LOWS IN THE 20S WITH 30S LIKELY
ON FRIDAY MORNING. THIS WILL CONTINUE TO AID DRYING AND THAWING OF AREA
SOILS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1139 PM CDT FRI MAR 14 2014

VFR CONDITIONS WILL BE OVER THE AREA THROUGH SATURDAY AFTERNOON.
HIGH PRESSURE MOVING THROUGH THE REST OF TONIGHT WILL KEEP LIGHT
WINDS OVER THE AREA. WINDS WILL BECOME EASTERLY BY MORNING AND WILL
INCREASE THROUGH THE DAY AS LOW PRESSURE MOVES SOUTH THROUGH
EASTERN NEBRASKA AND KANSAS AND STRENGTHENS. AN AREA OF SNOW IS
EXPECTED TO DEVELOP OVER NORTHERN IOWA SATURDAY AFTERNOON AND DROP
SOUTH THROUGH CENTRAL AND EAST CENTRAL IOWA AND NORTHERN ILLINOIS
SATURDAY EVENING. THE SNOW WILL BRING MVFR CIGS AND VISIBILITIES
TO AREAS NORTH OF I80 DURING THE EVENING.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...FLOOD WATCH THROUGH SATURDAY EVENING FOR HENRY IL-ROCK ISLAND.

MO...NONE.
&&

$$

UPDATE...DLF
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...NICHOLS
AVIATION...DLF