000 FXUS63 KMPX 101141 AAA AFDMPX AREA FORECAST DISCUSSION...UPDATED FOR 12Z TAFS NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 540 AM CST WED FEB 10 2010 .DISCUSSION... THE FORECAST CHALLENGES ARE TEMPERATURES TODAY AND TONIGHT FOLLOWED BY SNOW CHANCES FRIDAY AND SATURDAY. BELOW NORMAL TEMPERATURES WILL CONTINUE THIS FORECAST CYCLE WITH NORTHWEST UPPER LEVEL FLOW PREVAILING. THE ARCTIC RIDGE AT 1030 MB IS MOVING OVER THE FRESH SNOW COVER THIS MORNING...CENTERED OVER THE ERN DAKOTAS AND WRN MN. TEMPERATURES HAVE ACCORDINGLY BOTTOMED OUT 15 TO 20 BELOW ZERO. RIDGE WILL MOVE GRADUALLY EAST TODAY WITH A SUNNY SKY EXPECTED. THE EXCEPTIONS ARE WRN WI WHICH WILL SEE STRATOCU OFF LAKE SUPERIOR THIS MORNING...AND WRN MN WHICH WILL SEE TOUCHES OF AFTN CIRRUS. WITH THE LOW STARTING POINT IN TEMPERATURES OVER WRN MN...EVEN WITH A CLIMB OF 5 TO 10 DEGREES ABOVE THE NORMAL DIURNAL RANGE THIS TIME OF YEAR...TEMPS STILL LOOK TO BE ONLY IN THE LOW TEENS FOR HIGHS. HAVE ADJUSTED DOWN THE MAXS TODAY OVER THIS AREA WHERE TEMPS ARE STARTING THEIR COLDEST. FOR TONIGHT...THE RIDGE AXIS GLIDES EAST OVER ERN MN AND WRN WI WITH SIMILAR LOWER ATMOSPHERIC TEMPS AND LOW PWATS AS IN THE ERN DAKOTAS THIS MORNING. EXPECT ONLY A SLOW INCREASE IN CIRRUS AND ONLY OVERNIGHT OVER THE HEART OF THE RIDGE. SOME OF THE DEEPEST FRESH SNOW COVER WILL HAVE THE RIDGE OVER IT TONIGHT...FURTHER MAXIMIZING THE RADIATIONAL COOLING. SREF MEMBER PLUMES FOR MINNEAPOLIS INDICATE A FAIRLY LARGE OVERALL MEMBER SPREAD SHOWING MODEL UNCERTAINTY. HOWEVER FORECASTER CONFIDENCE CONTINUES TO INCREASE IN THE COLDEST MEMBERS COMING TO FRUITION. THIS IS FURTHER SUPPORTED BY A HANDFUL OF COOPERATIVE INSTITUTE FOR PRECIPITATION STUDIES /CIPS/ ANALOGS THAT MATCH THE COOLER GFS FORECAST AND CURRENT SNOW DEPTHS. SO AS PREVIOUS SHIFT...HAVE BLENDED GOING FORECAST TOWARDS THE MORE FAVORABLE GFS. THINK 10 TO 15 BELOW WILL BE COMMON IN OUTLYING AREAS...JUST A TAD WARMER THAN WHAT IS BEING EXPERIENCED THIS MORNING TO OUR IMMEDIATE WEST DUE TO SLIGHTLY WARMER AFTERNOON MAXS TO START WITH. OTHERWISE...NEXT DISTURBANCES REMAIN PROGNOSTICATED FOR FRIDAY AND SATURDAY. THE 00Z MODEL GUIDANCE CONTINUES TO SHOW SIZABLE DISAGREEMENTS ON PLACEMENT...ORIENTATION...AND TIMING OF THESE. IF SATURATION IS ABLE TO HAPPEN...THE MN PORTION OF THE FORECAST AREA WILL BE FAVORED FOR SOME SNOW BY BOTH WAVES. BUT BOTH ARE FAIRLY QUICK MOVING AND THE FIRST IS SHEARING OUT WITH FOCUSED BUT WEAK ASCENT. SO HAVE MADE LITTLE CHANGES TO THE SMALL POPS FOR THU NIGHT INTO FRI AS THEY CONTINUE LOOKING GOOD WITH THIS PATTERN AND THE LATEST GUIDANCE. FOR SAT...HAVE FURTHER INCREASED POPS OVER MUCH OF THE MN FORECAST AREA AS THE WELL DEVELOPED POTENTIAL VORTICITY LOBE TAKES A SIMILAR PATH TO THE ONE THIS PAST MONDAY...JUST A LOT QUICKER MOVING AND NOT AS DEEP. BEHIND THIS...SETUP FAVORS SLIGHTLY BELOW NORMAL TEMPERATURES INTO NEXT WEEK...WHICH IS SUPPORTED BY THE CPC 8 TO 14 DAY OUTLOOK AND 00Z NAEFS PROBABILISTIC GUIDANCE. && .AVIATION.../12Z TAF ISSUANCE/ NLY TRAJECTORIES STREAMING OFF LK SUPERIOR WL CONT TO BRNG MVFR CIGS INTO KEAU INTO THE AFTN HRS. W EDGE OF THESE CLDS HAS RMND FAIRLY STNRY LAST FEW HRS...BUT MAY CLIP KRNH...SO CARRIED SCT015 TIL 15Z. METARS AND 11-3.9 SATL SHWG THIN...BUT VERY LOW STRATUS IN EXT W MN VCNTY COLD SFC HIGH PRES. THESE SHUD RMN W OF RWF/AXN...AND EAST EDGE OF THESE CLDS SHUD BGN TO THIN OUT AFT SR. THREAT STRATUS/FOG DVLPG MANINLY E MN INTO WI COMING NIGHT AS COLD SFC RIDGE MVS IN. FOR NOW JUST INTRO SCT SC AND MVFR VSBYS. KMSP...LIGHT NLY WNDS TDY AHEAD OF APRCHG NARROW AXIS OF HI PRES. WNDS BCMG VRBL THIS EVE BFR COMING LGT SE LT IN TAF PRD. SOME THREAT OF STRATUS/FOG DVLPG COMING NITE UNDER COLD HIGH PRES. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MTF/BAP