417 FXUS63 KMPX 181105 AFDMPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 605 AM CDT SAT OCT 18 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 329 AM CDT SAT OCT 18 2014 QUIET SHORT TERM PERIOD AHEAD...WITH NO PRECIPITATION EXPECTED. CURRENTLY...WIDESPREAD LOW LEVEL CLOUD COVER CAN BE SEEN FROM THE GREAT LAKES THROUGH THE CENTRAL DAKOTAS DESPITE HIGH PRESSURE BUILDING IN FROM CANADA. CYCLONICALLY CURVED FLOW WILL REMAIN OVERHEAD THROUGH THE MORNING HOURS...AND MODEL SOUNDINGS INDICATE SIGNIFICANT DRYING TAKING PLACE IN THE MID AND UPPER LEVELS...BUT PLENTY OF MOISTURE WILL REMAIN IN THE BOUNDARY LAYER AND IT WILL TAKE UNTIL THE ANTI-CYCLONIC CIRCULATION COMBINED WITH WARMING TEMPERATURES ARRIVE TO SCATTER OUT THE CLOUD DECK FROM MID DAY THROUGH THE AFTERNOON. THIS UPDATE INTRODUCED A SLIGHT DELAY IN CLEARING SKIES FROM THE PREVIOUS FORECAST. THE SURFACE TEMPS WILL BATTLE THIS EXTENDED SKY COVER...SO SLIGHTLY LOWERED THE FORECAST HIGHS FOR TODAY. WINDS WILL BE FROM THE NORTH INITIALLY...AROUND 5-10 KTS BUT THE ELONGATE CENTER OF THE SURFACE HIGH WILL WORK ACROSS THE FA TODAY...SO EXPECT A FEW HOURS OF ESSENTIALLY CALM WINDS /EARLY ACROSS THE WEST...LATER EAST/ BEFORE THEY TURN SOUTHERLY ON THE BACK SIDE OF THE HIGH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 329 AM CDT SAT OCT 18 2014 THE LONG TERM FORECAST WILL BE MILD AND DRY OVERALL...AS A LARGE SCALE OMEGA BLOCK PATTERN PREVAILS FOR NEXT WEEK. THE ONLY PRECIPITATION CHANCES WILL BOOKEND THE TIMEFRAME...WITH SUNDAY AND THURSDAY APPEARING TO HAVE THE POTENTIAL TO PROVIDE A FEW SHOWERS DURING THE TRANSITIONS INTO AND OUT OF THE BLOCKING PATTERN. REGARDING SUNDAY PRECIPITATION CHANCES...MODELS HAVE CONTINUED TO TREND TOWARD A DRIER SOLUTION FOR THE LOCAL AREA...WITH THE BETTER MOISTURE/FORCING DISPLACED TO THE NORTH/EAST OF THE AREA. HAVE RETAINED A SLIGHT CHANCE OF SHOWERS IN THE FAR NORTHEAST NEAR LADYSMITH...BUT THE REMAINDER OF THE AREA SHOULD STAY DRY. BY MONDAY...THE SURFACE LOW SHIFTS WELL EAST OF THE AREA...AND THE MID LEVEL RIDGE WORKS INTO WESTERN MINNESOTA. HIGH TEMPERATURES IN THE 55 TO 65 DEGREE RANGE WILL THEN BE COMMON THROUGH WEDNESDAY. BY THURSDAY...A POTENT LITTLE SHORTWAVE PRESSES ACROSS THE ROCKIES AND HIGH PLAINS...AND BRINGS AN END TO THE MID LEVEL RIDGING. THE 18.00Z ECMWF WAS FASTER WITH THIS SCENARIO...AND BROUGHT SHOWERS INTO THE AREA AS EARLY AS WEDNESDAY MORNING. MEANWHILE...THE 18.00Z GFS WAS ABOUT 18 HOURS SLOWER WITH THE BAND OF RAIN. LEANED TOWARD THE ECMWF ENSEMBLE AS THE PREFERRED SOLUTION....WHICH EXPANDS PRECIPITATION EASTWARD ACROSS THE AREA ON WEDNESDAY AFTERNOON AND NIGHT...AND LINGERS IT ON THURSDAY. IN THE WAKE OF THIS SYSTEM...TEMPERATURES ARE UNAFFECTED...WITH HIGHS IN THE 60S EXPECTED ON FRIDAY. THE CHANCE OF LOW TEMPERATURES DIPPING BELOW FREEZING THROUGH THE EXTENDED FORECAST PERIOD NEXT WEEK IS LOW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 554 AM CDT SAT OCT 18 2014 THE FA WILL REMAIN SOCKED IN WITH MVFR CIGS THROUGH MUCH OF THE MORNING ACROSS THE EAST...AND EVEN LONGER TO THE WEST. THE LATEST NAM IS FAIRLY PESSIMISTIC IN TIMING THE SCATTERING OF THE CLOUD DECK TODAY. I DO THINK IT MAY BE OVERDOING THE RH VALUES INDICATED IN THE MODEL SOUNDINGS...BUT THE RAP HAD A GOOD HANDLE ON THE CLOUD COVER FOR MUCH OF THE NIGHT SO LEANED THAT DIRECTION. THIS RESULTED IN AN UPDATED FORECAST THAT EXTENDED THE MVFR CIGS BY A FEW HOURS AT MOST SITES...BUT NOT AS LONG AS THE LATEST NAM WOULD LIKE TO GO. SO THERE IS SOME DECENT UNCERTAINTY IN TIMING OF THE CLOUD DECK SCATTERING. WESTERN MN REMAINS LOCKED IN WITH THICKER CLOUD COVER SO IT WILL TAKE LONGER FOR IT TO SCATTER OUT. NORTHERLY WINDS WILL BECOME LIGHT AND VARIABLE AS A SURFACE HIGH PRESSURE AXIS WORKS ACROSS THE FA...THEN TURN SOUTHERLY LATER IN THE PERIOD. KMSP...CURRENT THINKING IS THAT THE CEILING WILL START BREAKING UP AROUND NOON BUT CONFIDENCE IN THIS IS NOT HIGH. NAM SOUNDINGS INDICATE THE POSSIBILITY OF THESE CEILINGS LASTING THROUGH MID AFTERNOON. /OUTLOOK FOR KMSP/ SUN...VFR. WINDS SW 10-15 KTS. MON...VFR. WINDS NW 10 KTS. TUE...VFR. WINDS SE 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...LS AVIATION...SPD