994 FXUS63 KMPX 202127 AFDMPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 327 PM CST THU NOV 20 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 320 PM CST THU NOV 20 2014 EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH 500MB HEIGHTS AND WINDS IDENTIFIED THE 3 MAIN PLAYERS THAT WILL IMPACT THE UPPER MIDWEST THIS WEEKEND AND EARLY NEXT WEEK. THE FIRST WAS A SHORTWAVE OFF THE CALIFORNIA COAST...WHICH IS FORECAST TO TRANSLATE SOUTHEASTWARD OVER THE NEXT 36 HOURS. THE NEXT IS A POWERFUL JET OFF THE NORTHWEST COAST...WHICH WILL BEGIN TO COME ON SHORE BY 00Z SATURDAY. THE THIRD IS THE SHORTWAVE IN THE LEFT EXIT REGION OF THIS JET WHICH AGAIN WILL BE JUST OFF THE BRITISH COLUMBIA COAST BY 00Z SATURDAY. IN THE MEAN TIME...HIGH PRESSURE CURRENTLY IN PLACE ACROSS THE UPPER MIDWEST WILL GRADUALLY SLIDE SOUTHEAST. THIS WILL SET THE STAGE FOR AMPLE RADIATIONAL COOLING AND ANOTHER COLD NIGHT ACROSS THE FORECAST AREA WITH MOST LOCATIONS DROPPING BELOW ZERO...ESPECIALLY IN WESTERN WI. BY FRIDAY MORNING SOUTHERLY FLOW ON THE BACKSIDE OF THIS DEPARTING HIGH PRESSURE WILL ADVECT MOISTURE ACROSS THE REGION. FORECAST SOUNDINGS SHOW STRATUS DEVELOPING FROM SOUTHWEST TO NORTHEAST. HIGH TEMPS WILL GENERALLY BE IN THE UPPER 20S...WHICH SHOULD BRING THE CONSECUTIVE DAYS OF SUB FREEZING NOVEMBER HIGHS AT MSP TO 12...MAKING IT SECOND ONLY TO 15 BACK IN 1880. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 320 PM CST THU NOV 20 2014 LONG TERM (FRI NIGHT-THU)...NOT MUCH CHANGE IN FCST REASONING TODAY AS MODEL SOLUTIONS ARE BECOMING AGREEABLE...WITH A SLIGHT EASTWARD SHIFT ON SUN/MON. WITH THAT SAID...THERE ARE STILL MULTIPLE CHALLENGING PERIODS AS A LARGE STORM SYSTEM TAKES SHAPE OVER THE CENTRAL U.S. HIGH PRESSURE WILL BE WELL TO OUR EAST BY FRI NIGHT WITH RETURN FLOW ALREADY WELL ESTABLISHED. THERE IS A WEAK SHORTWAVE IN THE NORTHERN STREAM THAT MAY PRODUCE A LITTLE LIGHT QPF OVERNIGHT FRI...AND WITH TEMPS SLOWLY WARMING THROUGH THE 20S...THE FAVORED P-TYPE WOULD LIKELY BE -FZDZ. THIS THREAT SHOULD BE CONFINED TO LOCATIONS ALONG AND EAST OF INTERSTATE 35. WITH THE WARM AIR ADVECTING OVER THE SNOWPACK...FOG IS ALSO A DISTINCT POSSIBILITY. THERE LOOKS TO BE A BREAK IN PRECIP FOR MUCH OF THE DAY SAT AND THE FIRST HALF OF SAT NITE AS LOW PRESSURE DEVELOPS IN TX IN ADVANCE OF A DIGGING TROUGH. MEANWHILE...A SECOND (AND WEAKER) LOW WILL BE MOVING ACROSS THE NORTHERN ROCKIES AT THE SAME TIME. TEMPS WILL WARM CONSIDERABLY SAT/SAT NITE AS WARM AIR AND MOISTURE GETS DRAWN NORTH. MODEL GUIDANCE IS SHOWING TEMPS INTO THE 40S ON SAT AND REMAINING ABOVE FREEZING SAT NIGHT. SAT NITE (AT LEAST THE SECOND HALF) WILL ONCE AGAIN FEATURE -RA/DZ AND PATCHY FOG MOST PREVALENT IN E MN/WI. WE WILL CONTINUE TO SEE -SHRA AT LEAST IN E MN & WI FOR THE FIRST HALF OF SUNDAY AS A CONSOLIDATION OF LOW PRESSURE CENTERS BEGINS TO OCCUR OVER THE SOUTHERN GREAT LAKES. THE MERGING OF THESE TWO LOWS WILL CAUSE A RAPID INTENSIFICATION OF A SINGULAR LOW SOMEWHERE IN THE GREAT LAKES EARLY MON. IF NOTHING ELSE...THIS RAPID DEEPENING OF THE LOW WILL PRODUCE STRONG WINDS FOR OUR AREA. COLD AIR WILL QUICKLY WRAP AROUND THE SYSTEM BY MON WITH ANY PRECIP CHANGING TO SNOW. IN TERMS OF PRECIP...THERE WILL BE A DEFORMATION AREA OF PRECIP STRETCHING BEHIND THE LOW ENHANCED BY THE UPPER LEVEL LOW MOVING DIRECTLY OVER THE STATE OF MN ON MON. AT THIS TIME IT LOOKS LIKE THE MAJORITY OF (SIGNIFICANT) SNOWFALL WILL BE CONFINED TO THE NORTHERN HALF OF MN...BUT THERE REMAINS A DECENT CHANCE FOR SNOW OVER THE ENTIRE REGION. POPS AT THIS JUNCTURE WILL REMAIN IN THE CHANCE CATEGORY WITH SNOWFALL AMOUNTS JUST TOO DIFFICULT TO NAIL DOWN. AS MENTIONED EARLIER...WIND WILL BE THE MAIN IMPACT FROM THIS SYSTEM WITH SUSTAINED WINDS GREATER THAN 20KT WITH GUSTS POTENTIALLY EXCEEDING 35KT. DEPENDING ON THE COMPOSITION AND AMOUNT OF SNOW...BLOWING AND DRIFTING SNOW MAY BECOME A SIGNIFICANT FACTOR. PLEASE STAY TUNED TO FUTURE FORECASTS AS WE REFINE SNOW CHANCES/AMOUNTS. THIS SYSTEM WINDS DOWN FOR US BY TUE AFTN WITH MORE BELOW AVERAGE TEMPS AND MINIMAL PRECIP CHANCES THRU WED. THERE IS THE THREAT FOR MORE -SN ON THANKSGIVING...BUT AT THIS POINT MODEL SPREAD IS PRETTY SIGNIFICANT SO ONLY SMALL CHANCES ARE WARRANTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1152 AM CST THU NOV 20 2014 VFR CONDITIONS TODAY AND TONIGHT...WITH MVFR CIGS SPREADING UP FROM SOUTHWEST LATE FRIDAY. NORTHWEST WINDS WILL DECREASE OVERNIGHT...AND BECOME SOUTHERLY AS THE NEXT WEATHER SYSTEM APPROACHES. THIS SYSTEM COULD SPREAD FREEZING DRIZZLE ACROSS THE REGION FRIDAY NIGHT. KMSP... ONLY NOTEWORTHY DIFFERENCE FROM GENERAL DISCUSSION WAS DECISION TO HOLD OFF ON ANY MVFR/IFR CONDITIONS AND MENTION OF FREEZING DRIZZLE WITH THIS TAF ISSUANCE. THE POTENTIAL IS THERE...BUT IT WOULD NOT BE UNTIL THE TAIL END OF THE TAF PERIOD HEADING INTO FRIDAY NIGHT. /OUTLOOK FOR KMSP/ FRI NIGHT...MVFR/IFR AND FZDZ POSSIBLE. WINDS SSW AT 15G20KTS. SAT...MVFR POSSIBLE. WINDS SSW 10G20KT. SUN...MVFR/IFR WITH FZDZ/RA POSSIBLE. WINDS SE 10 KT. MON...MVFR/IFR WITH -SN/BLSN POSSIBLE. WINDS NW AT 25G30KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JRB LONG TERM...JCA AVIATION...JRB