197
FXUS63 KDVN 130807
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
307 AM CDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 249 AM CDT TUE AUG 13 2013
INITIAL COLD FRONT WELL TO OUR SOUTH NEAR THE KSTL METRO ATTIM.
LIGHT NORTHERLY WINDS USHERING IN INITIAL SURGE OF COOLER AND
DRIER AIR WITH TEMPS IN THE U50S/L60S AT 07Z WHICH IS ABOUT 5-10
DEGS COOLER THAN 24 HRS AGO. SECONDARY LAKE ENHANCED FRONT
EXTENDS FROM NORTHEAST IL THROUGH SOUTHWEST WI ACCOMPANIED BY
ARCING BAND OF LOW CLOUDS PER 11-3.9 MICRON SATL IMAGERY. THIS
FRONT CONTAINS THE MAIN SURGE OF COOLER AND DRIER AIR WITH
TEMPS AND DEWPTS LOWERING INTO THE 40S ATTIM... WITH FEW 30S
FAR NORTHERN MN AND NORTHERN WI. FLOW ALOFT OVER REGION IS
NORTHWESTERLY WITH MID LEVEL SHEAR AXIS APPROACHING DENOTED IN
WATER VAPOR IMAGERY BY MARKED DRYING IN ITS WAKE FROM PARTS OF
ND/SD THROUGH MUCH OF WI. ACTIVE CONVECTION IS OCCURRING FROM
PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS WITHIN MAIN MOISTURE
AXIS AHEAD OF SHORTWAVE SLIDING E/SE FROM ROCKIES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 249 AM CDT TUE AUG 13 2013
EXTREMELY PLEASANT WX ON TAP WITH BELOW NORMAL TEMPS AND LOW
HUMIDITY. LAKE ENHANCED BOUNDARY TO PASS TDY WITH DEEP MIXING
LIKELY LOWERING DEWPTS INTO THE 40S TO AROUND 50 DEGS MANY AREAS
THIS AFTN. WILL SEE SOME THIN CIRRUS AND SCT-BKN STRATOCU MAKING
FOR PT-MOSUNNY SKIES TDY. ALSO... EARLY THIS AM MAY SEE SOME
SMOKE FROM CANADIAN FIRES SWEEP QUICKLY THROUGH MAKING FOR SOME
HAZY SKIES FOR SHORT TIME BEFORE PRONOUNCED DRYING ALOFT SURGES IN.
DEEP MIXING ABOVE 825 MB AND PROGGED LOW LEVEL THICKNESS AND
VERIFICATION OF HIGHS UPSTREAM YSTDY BOTH SUPPORTIVE OF WIDESPREAD
HIGHS IN THE 70S. MAINLY CLEAR SKIES AND COOL TNGT WITH WINDS
BECOMING NEAR CALM AS HIGH PRESSURE SETTLES OVERHEAD. EXCELLENT
RADIATIONAL SETUP FAVORS SIDING NEAR OR JUST BELOW COOL SIDE OF
GUIDANCE FOR LOWS... WITH GENERAL RANGE FROM 47-54F AND COULD SEE
A FEW SITES POSSIBLY WITHIN SEVERAL DEGS OF RECORDS. SEE CLIMATE
SECTION BELOW.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 249 AM CDT TUE AUG 13 2013
QUIET AND DRY CONDITIONS WILL BE SEEN WED/WED NIGHT WITH THE
CANADIAN HIGH OVER THE AREA. TEMPERATURES WILL CONTINUE TO AVERAGE
BELOW NORMAL.
THURS/THURS NIGHT THE MODELS HAVE DONE A MAJOR DEVIATION FROM
EARLIER RUNS AND HAVE A SIGNIFICANT SHORTWAVE MOVING THROUGH THE
AREA. SOME MODELS ATTEMPT TO DEVELOP AND BRING AN UPPER LOW ACROSS
THE AREA. INTERNALLY...THE MCS TOOL SUGGESTS A LOOSELY ORGANIZED
CONVECTIVE COMPLEX MOVING ACROSS IOWA AND BRUSHING THE FAR WESTERN
PART OF THE CWFA. GIVEN THAT THE OVERALL UPPER SUPPORT IS WEAK...
THE MODELS WILL LIKELY UNDERGO SEVERAL MORE SIGNIFICANT FLUCTUATIONS
OVER THE NEXT SEVERAL DAYS.
FRIDAY ON...
THE MODEL CONSENSUS YIELDS MAINLY DRY CONDITIONS ACROSS THE CWFA ON
FRIDAY WITH THE BULK OF ANY PRECIPITATION WEST OF THE CWFA.
FRIDAY NIGHT THROUGH MONDAY THE MODEL CONSENSUS HAS DRY CONDITIONS
ACROSS THE AREA AS YET ANOTHER CANADIAN HIGH SETTLES OVER THE
MIDWEST. TEMPERATURES WILL CONTINUE TO AVERAGE BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1142 PM CDT MON AUG 12 2013
HIGH PRESSURE BUILDING INTO NORTH DAKOTA WILL SPREAD SOUTHEAST
TONIGHT AND TUESDAY...PROVIDING MOSTLY CLEAR SKIES AND LIGHT
NORTH TO NORTHEAST WINDS. THERE IS A LOW POTENTIAL FOR SHALLOW
FOG EARLY IN THE MORNING...BUT AT THIS TIME THIS POTENTIAL LOOKS
TOO SMALL TO WARRANT MENTION IN THE TAFS. OTHERWISE...CONDITIONS
WILL REMAIN VFR.
&&
.CLIMATE...
ISSUED AT 249 AM CDT TUE AUG 13 2013
RECORD LOWS FOR AUGUST 14...
MOLINE.........45 IN 2004
CEDAR RAPIDS...43 IN 2004
DUBUQUE........46 IN 2004
BURLINGTON.....50 IN 2004
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...05
SHORT TERM...05
LONG TERM...08
AVIATION...SHEETS
CLIMATE...05