772 FXUS63 KAPX 120856 AFDAPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 356 AM EST FRI FEB 12 2010 .SYNOPSIS.../ISSUED AT 356 AM/ MAINLY QUIET WEATHER TO END THE WEEK ACROSS NORTHERN MICHIGAN...WITH A MIX OF CLOUDS AND SUN EXPECTED TODAY ALONG WITH SOME SNOW SHOWERS DOWNWIND OF LAKE MICHIGAN. MORE CLOUDS THAN SUN ARE EXPECTED FOR SATURDAY...WIT A CONTINUED THREAT FOR LIGHT SNOW SHOWERS IN SOME OF THE TYPICAL LAKE SUPERIOR AND LAKE MICHIGAN SNOW BELTS. JPB && .SHORT TERM.../ISSUED AT 356 AM/...TODAY 05Z SURFACE ANALYSIS SHOWS A NARROW RIDGE OF HIGH PRESSURE RUNNING NORTH/SOUTH FROM NORTHWEST ONTARIO SOUTHWARD ACROSS EASTERN IOWA/NORTHERN MISSOURI. CYCLONIC FLOW ACROSS THE UPPER LAKES TO THE EAST OF THIS RIDGE AND SHALLOW INSTABILITY SUPPORTING LAKE CLOUDS OFF LAKES SUPERIOR/MICHIGAN...00Z APX SOUNDING INDICATED A SHALLOW CBL WITH AN INVERSION AT 875MB/-12C...PIREPS NEAR TVC FROM LATE LAST EVENING SHOWING CLOUD DEPTHS OF 1500-2000FT. RADAR OCCASIONALLY SHOWING A BAND OR TWO OF HIGHER RADAR RETURNS WITH SOME LIGHT SNOW/FLURRIES ACROSS ANTRIM/OTSEGO/CRAWFORD COUNTIES. IR/WATER VAPOR IMAGERY AND GOES SOUNDING PRECIPITABLE WATER ANALYSES SHOW DRIER AIR TO THE EAST OF LAKE SUPERIOR TRYING TO PUSH INTO THE FORECAST AREA VIA THE BACK DOOR. EASTERN UPPER...CURRENT THINKING IS THAT MUCH OF THE LAKE CLOUDINESS OFF LAKE SUPERIOR WILL BE CONFINED TO FAR WESTERN CHIPPEWA AND WESTERN MACKINAC COUNTIES TODAY...WITH MORE SUN TO THE EAST. WILL BE WATCHING CLOUD COVER ADVANCING SOUTHWEST OUT OF NORTHEAST ONTARIO...BUT THINKING THAT MUCH OF THAT WILL NOT BE AN ISSUE UNTIL TONIGHT. AFTERNOON HIGHS LOWER-MID 20S MOST AREAS...UPPER 20S/ AROUND 30 WESTERN MACKINAC COUNTY. NORTHERN LOWER...LAKE CLOUDS WILL BE MORE PERSISTENT ACROSS MUCH OF NORTHWEST LOWER AND DOWN TOWARD THE SAGINAW BAY REGION...ALONG WITH OCCASIONAL LIGHT SNOW SHOWERS/FLURRIES. BASED ON FORECAST TRAJECTORIES ANTICIPATE CLOUDS WILL BE THINNER ACROSS FAR NORTHEAST LOWER AND EVENTUALLY THE TIP OF THE MITT. AFTERNOON HIGHS MID 20S/ AROUND 30. JPB && .LONG TERM.../ISSUED AT 356 AM/...TONIGHT AND BEYOND LARGE SCALE PATTERN FEATURES SEVERAL SHORT WAVES ROTATING AROUND A RATHER WEAK FLOW PATTERN ACROSS THE UPPER MIDWEST/GREAT LAKES/ EASTERN CANADA. ELONGATED VORTICITY PATTERN ACROSS MICHIGAN/ NORTHERN WISCONSIN PER WATER VAPOR IMAGERY...WITH AN UPPER LEVEL HIGH OVER HUDSON BAY SENDING ONE WAVE SOUTHWEST OUT OF QUEBEC AND TOWARD THE UPPER GREAT LAKES. ADDITIONAL SHORT WAVE ENERGY WAS CROSSING IOWA EARLY THIS MORNING...AS WELL AS IN THE VICINITY OF LAKE WINNIPEG. IOWA SHORT WAVE WILL SLIDE EAST ACROSS THE OHIO VALLEY...WHILE THE PIECE OF ENERGY COMING OUT OF QUEBEC LOOKS TO SLIDE INTO THE REGION SATURDAY. MORE INTERESTINGLY...REMAINS OF THE LATEST MID ATLANTIC BLIZZARD FORECAST TO ROTATE NORTH/NORTHWEST BACK TOWARD NEWFOUNDLAND THIS WEEKEND...WITH THE POSSIBILITY THAT THE EXPANSIVE CIRCULATION AROUND THIS LOW THROWS MOISTURE BACK TOWARD THE UPPER GREAT LAKES FOR SUNDAY/MONDAY. NEAR TERM FORECAST ISSUES DEAL WITH LINGERING LAKE CLOUDS AND EFFECTS OF SHORT WAVE AND ASSOCIATED MOISTURE MOVING IN FROM THE NORTHEAST LATER TONIGHT AND INTO SATURDAY. TONIGHT...CLOUDS ASSOCIATED WITH SHORT WAVE ENERGY COMING OUT OF QUEBEC ARRIVE LATER TONIGHT...OVERSPREADING EASTERN UPPER AND MUCH OF NORTHERN LOWER. SOME WEAK ISENTROPIC ASCENT MAY SQUEEZE OUT A FEW FLURRIES BUT LOOKS LIKE "SYNOPTIC" PRECIP POTENTIAL IS MINIMAL. LAKE CONVECTION WILL CONTINUE TO BE AN ISSUE FOR NORTHWEST LOWER... LOW LEVEL FLOW TURNING MORE NORTHEASTERLY ACROSS EASTERN LAKE SUPERIOR WILL TEND TO LIMIT LAKE SC GETTING INTO EASTERN UPPER TONIGHT. LAKE INDUCED CBL STILL SHALLOW BUT IS FORECAST TO CLIMB A BIT CLOSER TO 850MB AS LOW LEVELS COOL A LITTLE MORE. LOW LEVEL FLOW IN THE 330-340 RANGE WOULD TARGET AREAS WEST OF I-75 FOR LIGHT SNOW SHOWER ACTIVITY. SATURDAY...EXPECTING A GOOD DEAL OF CLOUD COVER ACROSS NORTHERN MICHIGAN FOR SATURDAY...BETWEEN LAKE CLOUDS AND AFOREMENTIONED MID/UPPER LEVEL MOISTURE THAT SHOULD LINGER AT LEAST THROUGH SATURDAY MORNING. INCREASED SYNOPTIC MOISTURE AND A SMALL BOOST IN INVERSION HEIGHTS WILL IMPROVE LAKE EFFECT SNOW SHOWER CHANCES ACROSS NORTHWEST LOWER IN AREAS FAVORED BY 330-340 FLOW...AND HAVE BEEFED UP SNOW CHANCES WEST OF I-75 THROUGH SATURDAY NIGHT. EARLY EXTENDED (SUNDAY THROUGH TUESDAY)...SUNDAY INTO SUNDAY NIGHT HAS SOME INTERESTING POTENTIAL AS DEEPER MOISTURE ROTATES IN FROM THE NORTHEAST...WITH SOME POTENTIAL FOR SEVERAL INCHES OF LAKE ENHANCED SNOWFALL AS INVERSION HEIGHTS COULD GET A BOOST FROM SYNOPTIC SUPPORT AND PERHAPS A SHOW OF LOW LEVEL COLD AIR. WILL MAKE MENTION OF THIS POTENTIAL IN MORNING RENDITION OF THE HAZARDOUS WEATHER OUTLOOK. ONLY CHANGE TO MONDAY/TUESDAY FORECAST WAS TO KEEP SNOW CHANCES GOING INTO MONDAY NIGHT. JPB && .MARINE.../ISSUED AT 356 AM/ HEADLINE CONDITIONS NOT ANTICIPATED WITHIN MANISTEE-GRAND TRAVERSE LIGHT NEARSHORE ZONE THROUGH SATURDAY NIGHT...THOUGH NORTHWEST WINDS WILL PICK UP SATURDAY AND COULD SEE SPEEDS APPROACH SMALL CRAFT CRITERIA BY SATURDAY AFTERNOON/NIGHT. JPB && .AVIATION.../ISSUED AT 1150 PM/...VALID FOR 06Z TAFS NW FLOW OFF LAKE MICHIGAN WILL LEAD TO LOW VFR/MVFR CIGS AND FLURRIES ACROSS THE SNOWBELT REGIONS...INCLUDING ALL NRN LWR MICHIGAN TAF SITES. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$