676 FXUS63 KAPX 281118 AFDAPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 718 AM EDT MON JUL 28 2014 .SYNOPSIS... ISSUED AT 303 AM EDT MON JUL 28 2014 LOW PRESSURE IN THE EASTERN GREAT LAKES WILL MOVE EAST AND THEN NORTH...REACHING NORTHERN QUEBEC ON WEDNESDAY. WE WILL REMAIN IN THE BACKWASH OF THIS SYSTEM ALL WEEK...KEEPING OUR WEATHER ON THE COOL SIDE...AND PROVIDING US WITH OCCASIONAL CHANCES FOR SHOWERS. && .UPDATE... ISSUED AT 718 AM EDT MON JUL 28 2014 LOW CLOUDS THAT HAVE BEEN TRYING TO INVADE FROM NORTHERN ONTARIO WERE CONTINUING TO SEE EROSION ALONG THE LEADING EDGE. BUT HAVE NO FEAR...AS THE LOW CLOUDS HAVE RE-MATERIALIZED ACROSS MUCH OF NORTHERN LOWER. HAVE DRASTICALLY INCREASED MORNING CLOUD COVER ACROSS MUCH OF THE FORECAST AREA. AM CAUTIOUSLY LEAVING MAX TEMPS ALONE FOR NOW. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 303 AM EDT MON JUL 28 2014 ...ANOTHER TOUCH OF EARLY FALL-LIKE WEATHER... HIGH IMPACT WEATHER POTENTIAL: MINIMAL. WHAT THERE ARE CENTER ON MARINE SCA HEADLINES. PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: STRONG CAA WELL UNDERWAY ACROSS THE NORTH WOODS AT THIS EARLY HOUR...COURTESY OF DEEP NORTH FLOW ON BACKSIDE OF VIGOROUS EASTERN LAKES SHORTWAVE. SYSTEM ITSELF HELPING ESTABLISH ANOMALOUSLY DEEP OVERHEAD TROUGHING...THE CENTER OF WHICH IS LARGE GYRE SPINNING ACROSS CENTRAL QUEBEC. SHOWERS AND STORMS OF YESTERDAY NOW A THING OF THE PAST...WITH SAID CAA ALSO ACCOMPANIED BY RATHER STOUT DRY AIR ADVECTION (AS IT OFTEN IS). TROUGHING...HOWEVER...REMAINS UNSETTLED...WITH ANOTHER SLUG OF DEEPER MOISTURE TIED TO WEAK IMPULSE MAKING STEADY SOUTH PROGRESS ACROSS NORTHERN ONTARIO. LARGER SCALE PATTERN EXPECTED TO CHANGE LITTLE OVER THE NEXT 24 HOURS...SETTING THE STAGE FOR ANOTHER BOUT OF MID SUMMER CHILL TODAY AND TONIGHT...ALONG WITH SOME LATE NIGHT LIGHT RAIN CONCERNS AS UPSTREAM MOISTURE AXIS DROPS FURTHER SOUTH. PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPERATURE AND CLOUD TRENDS THROUGHOUT. ACCESSING RAIN CHANCES VERY LATE TONIGHT. DETAILS: WELL...AFTER DAYS OF TALKING ABOUT IT...ANOTHER BOUT OF EARLY FALL-LIKE CHILL HAS ARRIVED. CAA EXPECTED TO CONTINUE RIGHT THROUGH THIS MORNING AND EARLY AFTERNOON...WITH H8 TEMPERATURES BOTTOMING OUT IN THE MID SINGLE DIGITS. DIURNAL RESPONSE WILL TRY ITS BEST TO OFFSET...BUT SIMPLE LOW LEVEL THERMAL PROFILES SUPPORT HIGHS ONLY REACHING THE MID AND UPPER 60S. THESE ARE A GOOD 10 TO 15 DEGREES BELOW NORMAL! INCREASINGLY GUSTY WINDS WILL ONLY ADD TO THE CHILL...WITH DEEPENING MIXED LAYER SUPPORTING WIND GUSTS OF 20 TO 25 MPH. GOOD NEWS IS IT SHOULD BE A DRY DAY...WITH STRONG CAP UP NEAR H7 AND DRY LOW LEVELS. NO DOUBT SOME DIURNALLY DRIVEN CU WILL FORM...BUT THESE LOOK TO REMAIN SHALLOW-TOPPED AND SHOWER FREE. MOISTURE CONTINUES TO INCREASE FROM THE NORTH HEADING THROUGH TONIGHT AS SUBTLE WAVE PULLS INTO THE NORTHERN LAKES. TRENDS HAVE BEEN A TOUCH MORE AGGRESSIVE WITH INCREASING CLOUDS...WHICH HAS SOME MERIT GIVEN CURRENT VFR BROKEN/OVERCAST CONDITIONS MOVING ACROSS NORTHWEST ONTARIO. WILL TREND TOWARD THIS MORE AGGRESSIVE DIRECTION...ALTHOUGH NOT GOING QUITE AS CLOUDY AS MOST GUIDANCE WOULD SUGGEST. CANNOT COMPLETELY RULE OUT A LATE NIGHT SPRINKLE ACROSS THE NORTH...BUT SUCH LOW POTENTIAL ON WHAT WOULD BE A TRIVIAL EVENT JUST NOT WORTHY OF A SPECIFIC MENTION IN THE FORECAST. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 303 AM EDT MON JUL 28 2014 ...MUCH COOLER THAN NORMAL TO CLOSE OUT JULY... THE UPPER LOW IN CENTRAL QUEBEC WILL TEND TO RETROGRADE SLIGHTLY... AS IT FULLY ABSORBS THE UPPER LOW THAT GAVE US SUCH AN EXCITING DAY YESTERDAY. THE SYSTEM WILL BACK UP TO THE VICINITY OF JAMES BAY BY THURSDAY MORNING. AT THE SURFACE...BROAD BUT WEAK NW-ERLY FLOW WILL BE IN PLACE. THERE TENDS TO BE SOME WEAK TROFFING IN PLACE OVER NORTHERN MI TUESDAY...WHICH IS DISPLACED DOWNSTATE BY WEDNESDAY. TEMP TRENDS AND SMALL PRECIP CHANCES THE MAIN CONCERNS. TUESDAY...A VORT MAX ROTATING AROUND THE LARGE LOW IS PROGGED TO PIVOT FROM NORTH OF SUPERIOR TO FAR NORTHERN LOWER MI. DEEP CYCLONICALLY-CURVED FLOW WILL ASSIST THIS VORT IN PRODUCING A RATHER LARGE MOISTURE PLUME (850-500MB RH MAINLY 75-80 PERCENT). THE CONTINUED STEEP-ISH LAPSE RATES (700-500MB 6-6.5 C/KM) WILL HELP SUPPORT 100-300J/KG OF MUCAPE...EVEN IN THE MORNING. DIURNAL HEATING WILL BOOST THOSE NUMBERS TO 500-700J/KG IN THE AFTERNOON...JUST IN TIME FOR SOME ACTUAL FORCING. SO POPS NEEDED IN MOST AREAS MOST OF THE DAY...BUT WILL BE HIGHEST IN THE AFTERNOON IN N CENTRAL AND NE LOWER MI. LAKES MI AND SUPERIOR WILL ATTEMPT TO PROVIDE SMALLISH RAIN SHADOWS. WILL REDUCE (THOUGH NOT ELIMINATE) POPS IN THE MORNING...AND REMOVE AM THUNDER. WILL BOOST NE LOWER TO LIKELY POPS IN THE AFTERNOON. SMALL HAIL COULD BE RELATIVELY COMMON IN THE AFTERNOON GIVEN THE CHILLY TEMPS ALOFT. MAX TEMPS MAINLY UPPER 60S TO AROUND 70F. TUE NIGHT/WED...SHRA THREAT MAY LINGER INTO TUESDAY EVENING IN SE SECTIONS...BEFORE EXITING OVERNIGHT. ALSO...LEFTOVER SHRA FROM FAR NORTHERN ONTARIO MAY BE ABLE TO SUSTAIN THEMSELVES FOR A WHILE IN THE STEEP LAPSE RATE ENVIRONMENT. SOME REMNANTS OF THESE COULD CONCEIVABLY POKE INTO EASTERN UPPER OVERNIGHT...THOUGH FOR NOW WILL NOT MENTION. ON WEDNESDAY...THE BIG BALL OF WRAPAROUND MOISTURE FROM THE UPPER LOW WILL BE JUST SKIRTING BE N AND E OF THE FORECAST AREA. POPS DO NOT NEED TO BE AS HIGH AS ON TUESDAY...BUT THEY DO APPEAR NEEDED THRU THE DAY IN EASTERN UPPER...CLOSEST TO THAT CHILLY LOW TO THE NNE. ALSO KEPT SOME PM POPS IN FAR SE SECTIONS...FURTHEST AWAY FORM LAKE SHADOWING IN AN AIRMASS THAT IS OTHERWISE NOT ESPECIALLY MOIST. MIN TEMPS UPPER 40S TO LOWER 50S. MAX TEMPS MAINLY WITHIN A FEW DEGREES OF 70F. REST OF THE FORECAST...THE UPPER LOW TO OUR NE FINALLY EJECTS FRIDAY AND BEYOND...THOUGH A RATHER SHARP TROF CONTINUES TO LINGER BACK ACROSS THE LAKES REGION (OF COURSE IT DOES). THAT SHOULD ALLOW TEMPS TO SLOWLY MODERATE...THOUGH IT WILL TAKE A WHILE FOR US TO APPROACH NORMAL. AND THAT DOES LEAVE US WITH A PLEASANT ENOUGH WEEKEND AHEAD. AS FOR PRECIP...STAYING BENEATH TROFFING ALOFT POTENTIALLY KEEPS THE DOOR OPEN FOR DIURNAL PRECIP. THIS MAY GET SOME SYNOPTIC ASSISTANCE ON FRIDAY...WHEN EVEN AS THE UPPER LOW STARTS TO EXIT...THE TRAILING TROF MAKES A BIT OF A PUSH INTO THE REGION FROM THE NW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 718 AM EDT MON JUL 28 2014 MVFR CIGS THIS MORNING/EARLY AFTERNOON AT APN/TVC/MBL. OTHERWISE VFR. COOL AND MOIST LOW-LEVEL AIR CONTINUES TO SPILL INTO THE REGION...BEHIND LOW PRESSURE NOW OVER THE EASTERN GREAT LAKES. MVFR CIGS ARE ALREADY SEEN THIS MORNING AT APN/TVC/MBL. WILL TAKE SEVERAL HOURS FOR A LITTLE BIT OF HEATING TO ALLOW CIGS TO RISE TO VFR. VFR CONDITIONS WILL THEN PREVAIL INTO TONIGHT. GUSTY N TO NW WINDS TODAY...LIGHT NW WINDS TONIGHT. && .MARINE... ISSUED AT 303 AM EDT MON JUL 28 2014 NORTH WINDS WILL GRADUALLY BACK AROUND TO NORTHWEST TODAY...BECOMING MORE WESTERLY BY TUESDAY. GUSTY CONDITIONS WILL CONTINUE...WITH SPEEDS SLOWLY SUBSIDING FROM WEST TO EAST TODAY INTO THE OVERNIGHT. SCA CONDITIONS WILL CONTINUE TODAY ACROSS MUCH OF LAKE MICHIGAN AND HURON...WITH SCA CONDITIONS LIKELY CONTINUING THROUGH MUCH OF THE OVERNIGHT OFFSHORE OF NORTHEAST LOWER MICHIGAN. WINDS AND WAVES LOOK TO LARGELY REMAIN BELOW HEADLINE CRITERIA TUESDAY THROUGH THE REMAINDER OF THE WEEK. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ347>349. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323- 342-344>346. LS...NONE. && $$ UPDATE...JZ SYNOPSIS...JZ SHORT TERM...MSB LONG TERM...JZ AVIATION...JZ MARINE...MSB