FXUS63 KDVN 201956 AFDDVN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 256 PM CDT SAT MAR 20 2010 .SYNOPSIS... MORNING ANALYSIS HAD THE UPPER TROF OVER THE FRONT RANGE OF THE ROCKIES INTO WEST TX. WEAK H8 LOW WAS LOCATED OVER SRN OK WITH A STATIONARY H8 FRONT AND STRONG BAROCLINIC ZONE EXTENDING NE THROUGH SE IA INTO SRN LM. LATEST SURFACE ANALYSIS HAD THE SURFACE FRONT NEAR THE OHIO RIVER INTO THE EAST TX WITH A SURFACE LOW OVER WRN OK. A WIDE RANGE OF CONDITIONS CURRENTLY EXIST ACROSS THE CWFA. DRY NE FLOW OVER THE UPPER MS VALLEY AND WRN GRT LAKES HAS SHUT DOWN MOST OF THE SN OVER THE NW THIRD OF THE CWFA WITH THE NW CORNER PROBABLY SEEING SOME SUN AND TEMPS APPROACHING 40 DEGREES. OVER THE SERN 2/3RDS THOUGH LOW LEVEL CONVERGENCE NEAR THE H8 BOUNDARY AND FGEN CONTINUE TO SUPPORT BANDS OF -SN/SN WITH TEMPS HOLDING IN THE LOW TO MID 30S. && .SHORT TERM...TONIGHT AND SUNDAY... SHORT RANGE MODELS SUPPORT SNOW CONTINUING OVER THE SERN HALF TO TWO THIRDS OF THE CWFA INTO THIS EVENING AS THE TX UPPER LOW HEADS INTO THE MS VALLEY AND UPPER DIFFLUENCE SLIDES EAST ACROSS NRN MO AND WRN IL AND LOW LVL CONVERGENCE IS MAINTAINED NEAR THE STATIONARY H8 BOUNDARY. AREA OF -SN/SN CURRENTLY MOVING NE THROUGH NW MO SHOULD HOLD TOGETHER AS IT MOVES ACROSS THE SERN HALF OF THE CWFA LATE THIS AFTERNOON AND THIS EVENING. EXPECT ADDITIONAL SNOW FALL AMOUNTS OF 1 TO POSSIBLY 3 INCHES BY MIDNIGHT WITH THE HIGHER AMOUNTS OVER THE FAR SRN CWFA. THE NW THIRD SHOULD REMAIN PCPN FREE AS NELY FLOW CONTINUES TO FEED DRY AIR INTO THE REGION. WILL CONTINUE THE ADVISORY WITH THIS ISSUANCE. IMPACTS ARE EXPECTED TO BE MINOR BUT WITH THE POTENTIAL FOR A FEW MORE ROUNDS OF MOD SNOW...ESPECIALLY AFTER SUNSET...AND WITH ROAD SURFACES COOLING OFF WITH THE SNOW EARLIER TODAY...FEEL THERE IS STILL POTENTIAL FOR SOME LESSER TRAVELLED ROADS...BRIDGES AND OVERPASSES TO BECOME SLIPPERY. BY MIDNIGHT WE SHOULD SEE PCPN WINDING DOWN AS BETTER FORCING MOVES EAST OF THE AREA. KEPT TONIGHTS TEMP CLOSE TO THE LOWER MOS NUMBERS WITH DIMINISHING WINDS AHEAD OF SURFACE RIDGE BUILDING INTO NW IA AND HIGH CLOUDS THINNING. CLOUDS AND PCPN SHOULD KEEP TEMPS FROM DROPPING MUCH OVER THE SERN HALF OF THE CWFA. FOR SUNDAY THE SERN CWA WILL BE ON THE FRINGE OF THE CYCLONIC FLOW AROUND THE SURFACE LOW MOVING THROUGH THE LOWER OH VALLEY SO EXPECT CLOUDS TO LINGER THERE THROUGH MUCH OF THE DAY. WILL ALSO KEEP SOME LOW CHANCE POPS GOING. PCPN BY THEN SHOULD BE MAINLY -RA AS WARMER AIR WRAPS IN FROM THE NE. THE NW THOUGH SHOULD SEE MOSTLY SUNNY SKIES. THE SUN SHOULD HELP TEMPS IN THE NW RECOVER INTO THE MID/UPPER 40S WHILE THE CLOUDS IN THE SE WILL KEEP TEMPS FROM RISING MUCH ABV THE LOW 40S. ..DLF.. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY... WX TO BE GENERALLY QUIET SUNDAY NIGHT/MONDAY AS THE LAST REMNANTS OF THE WEEKEND STORM EXITS THE AREA. WET GROUND...CLEARING SKIES...AND DECREASING WINDS COULD RESULT IN SOME FOG DEVELOPMENT SUNDAY NIGHT/MONDAY. FOR NOW WILL ONLY GO WITH PATCHY FOG SUN NIGHT AS MODELS ARE STILL SOMEWHAT MIXED REGARDING FOG POTENTIAL. QUIET WX IS EXPECTED MONDAY NIGHT/TUESDAY AS HIGH PRESSURE MOVES ACROSS THE REGION. TUESDAY NIGHT/WEDNESDAY A WEAK FRONT MOVES THROUGH THE AREA. MOISTURE IS EXTREMELY LIMITED BUT MODELS INDICATE SOME FORCING WITH CONDENSATION PRESSURE DEFICITS LOWERING. THEREFORE...WILL GO WITH SCHC POPS WITH THE IDEA THAT SPRINKLES ARE THE MORE PROBABLE OUTCOME. WED NIGHT THROUGH THURSDAY NIGHT IS SOMEWHAT IN QUESTION. PHASING ISSUES WITH THE RESPECTIVE ENERGIES AND SMOOTHING OF MODEL SOLUTIONS ARE CONTRIBUTING TO DIVERGING MODEL SOLUTIONS. GFS/UKMET WOULD SUGGEST MOST OF THE TIME PERIOD BEING DRY WHILE THE GEM/ECMWF BRUSH THE SOUTH WITH THE NEXT SYSTEM. EXTRAPOLATION OF THE WRF BEYOND F84 SUGGESTS IT COULD GO EITHER WAY. THEREFORE...WILL CONTINUE WITH THE SCHC POPS THROUGH THE PERIOD BUT CONFINE THEM TO THE SOUTHERN HALF TO THIRD OF THE CWFA. FRIDAY ON...GENERALLY DRY WX LOOKS TO BE IN STORE FOR THE AREA. SOLUTIONS DIFFER ON TIMING BUT THE GFS/ECMWF SUGGEST ANOTHER SYSTEM POSSIBLY AFFECTING OR PASSING VERY CLOSE TO THE AREA THE SECOND HALF OF NEXT WEEKEND. ...08... && .AVIATION... ANOTHER ROUND OF SNOW LIFTING NE OUT OF MO SHOULD RETURN/KEEP MVFR TO IFR CONDITOINS AT KBRL/KMLI. KDBQ/KCID EXPECTED TO BE JUST NORTH OF THE SIGNIFICANT PCPN THROUGH THE EVENING...BUT A PERIOD OF MVFR CIGS/VSBY IN -SN IS POSSIBLE. AFTER MIDNIGHT EXPECT ANY LINGERING LOW CLOUDS TO MOVE SE OF KDBQ/KCID. SOME LIGHT FOG IS POSSIBLE BY SUNRISE THOUGH AS SKIES CLEAR AND WINDS DIMINISH OTHERWISE EXPECT VFR CONDITIONS THROUGH 18Z SUNDAY. 06Z-12Z KMLI/KBRL TO REMAIN UNDER AN MVFR CLOUD DECK WITH VSBYS OF 3-5SM AT TIMES IN -SN. CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AT KMLI AFTER 15Z BUT KBRL WILL BE ON THE FRINGE OF CYCLONIC FLOW AROUND OH VALLEY LOW PRESSURE...SO MVFR CONDITIONS MAY HANG ON THROUGH MID DAY SUNDAY. ..DLF.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR DES MOINES-HENRY IA-LEE-LOUISA-MUSCATINE-SCOTT-VAN BUREN. IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR HANCOCK- HENDERSON-MCDONOUGH-MERCER-ROCK ISLAND-WARREN. MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR CLARK- SCOTLAND. && $$ DLF/08