RSS FeedsIssued by NWS Green Bay, WI
000 FXUS63 KGRB 251033 AFDGRB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 433 AM CST WED NOV 25 2009 .SHORT TERM...TODAY THROUGH THANKSGIVING DAY. UPPER LOW LIFTING SLOWLY NORTHEAST FROM LAKE MICHIGAN EARLY TODAY WHILE ANOTHER UPPER LOW DIVES SOUTHEAST FROM THE EASTERN DAKOTAS TO NORTHERN ILLINOIS. LIGHT TO MODERATE RAIN WILL CONTINUE THROUGH MID MORNING OVER THE EASTERN HALF OF THE FORECAST AREA THEN IT SHOULD DIMINISH TO SCATTERED LIGHT RAIN OR DRIZZLE AS LOW LEVEL WARM ADVECTION AND CONVERGENCE COMES TO AN END. RAIN WILL PICK UP AGAIN LATE IN THE DAY AND TONIGHT IN CENTRAL AND EAST CENTRAL WISCONSIN AS LEFT EXIT REGION OF UPPER JET MOVES ACROSS. PRECIPITATION TYPE ISSUES SHOULD BE MINIMAL THROUGH THE DAYLIGHT HOURS THEN BEGIN TO GET A BIT MORE CHALLENGING TONIGHT. 850MB TEMPERATURES COOL TO -2C TO -4C IN THE CENTRAL COUNTIES TONIGHT WHICH WOULD USUALLY BE COLD ENOUGH TO GET SNOW AT THIS TIME OF YEAR. BUT NOVEMBER HAS BEEN UNUSUALLY WARM AND THE GROUND QUITE WARM AS WELL. SO EXPECT THAT THE RAIN WILL CHANGE TO SNOW TONIGHT BUT NOT ACCUMULATE TO ANY GREAT EXTENT DUE TO MILD BOUNDARY LAYER TEMPERATURES AND WARM GROUND. THERE MAY BE AN INCH OR SO ON GRASSY SURFACES. IN ADDITION TO PRECIPITATION TYPES ISSUES TONIGHT...THERE IS ALSO A QUESTION OF THE NORTHWARD EXTENT OF THE SIGNIFICANT PRECIPITATION. THE AXIS OF BEST PRECIPITATION HAS SHIFTED SOUTHWARD IN THE LAST FEW MODEL RUNS SO THAT WILL LIMIT CHANCE OF ACCUMULATING SNOW IF THAT TREND CONTINUES. WILL MENTION THE CHANCE OF SOME SMALL SNOW ACCUMULATIONS ON THE GRASS IN THE HAZARDOUS WEATHER OUTLOOKS. SNOW/RAIN SHOWERS SHOULD END EARLY THANKSGIVING DAY THEN IT WILL BE BLUSTERY AND COLDER. LAKE EFFECT SNOW SHOWERS IN VILAS COUNTY COULD PRODUCE AN INCH NEAR THE MICHIGAN BORDER. .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. THE MAIN CONCERN DURING THIS PART OF THE FORECAST IS AN APPROACHING SYSTEM THAT IS EXPECTED TO IMPACT THE AREA DURING THE LATTER PART OF THE WEEKEND. MODELS WERE IN GOOD AGREEMENT IN REMOVING PRECIPITATION FROM THE FORECAST AREA BY LATE THIS WEEK. THERE IS ONLY A SLIGHT CHANCE OF SNOW SHOWERS IN NORTHERN DOOR COUNTY AS THE SURFACE AND UPPER LEVEL SYSTEMS DEPART. WINDS SHOULD NOT BE FROM A FAVORABLE DIRECTION FOR LAKE EFFECT IN THE NORTH-CENTRAL PART OF THE STATE. SURFACE HIGH PRESSURE AND A RELATIVELY LOW AMPLITUDE UPPER LEVEL RIDGE SHOULD KEEP THE AREA DRY FOR MOST OF THE WEEKEND. MODELS DIFFERED IN THEIR HANDLING OF A SURFACE LOW EXPECTED TO PASS THROUGH THE REGION DURING THE LATTER HALF OF THE WEEKEND...AHEAD OF AN APPROACHING UPPER TROUGH. 00Z GFS HAD THE MAIN SURFACE LOW PASSING SOUTH OF THE STATE...WHILE THE 00Z ECMWF HAD A STRONGER LOW FORECAST TO MOVE THROUGH WISCONSIN. HPC MANUAL GUIDANCE PRODUCTS FROM MIDDAY TUESDAY HAD THE LOW FARTHER SOUTH THAN THE EC SOLUTION...AND MEDIUM RANGE COMPARISON DID NOT SEEM TO INDICATE A CONSENSUS...SO HAVE GONE WITH A SOLUTION CLOSER TO THE 00Z GFS...HIGHER POPS TO THE SOUTH AND LOWER TO THE NORTH SUNDAY AND SUNDAY NIGHT. ONLY MINOR CHANGES WERE MADE TO TEMPERATURES. && .AVIATION...IFR CIGS AND/OR VSBYS WILL GRADUALLY INCREASE TO MVFR IN MOST PLACES THIS EVENING AND TO VFR THANKSGIVING DAY. SOME WET SNOW POSSIBLE OVERNIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ RDM/MG
