FXUS63 KDLH 272330 AFDDLH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 630 PM CDT SUN MAR 27 2011 .AVIATION... /00Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT ALL TERMINALS. UW-MADISON CRAS AND NAM MODEL CLOUD FORECASTS KEEP NE MN AND NW WI IN AN AREA OF CLEAR SKIES THROUGH MONDAY NIGHT AS THE BLOCKED FLOW PATTERN CONTINUES AND HIGH PRESSURE REMAINS IN PLACE. FORECAST SOUNDINGS SHOW A SMALL CHANCE OF SOME SCT CU AROUND 4000-5000 FT AGL TOMORROW AFTERNOON...BUT DID NOT INCLUDE IN THE TAFS AT THIS TIME WITH THE AMOUNT OF DRY AIR IN PLACE. && .PREV DISCUSSION... /ISSUED 309 PM CDT SUN MAR 27 2011/ DISCUSSION...SPLIT FLOW IN WESTERLIES CONTINUES WITH CWA REMAINING WELL NORTH OF PRIMARY BAROCLINIC ZONE AND SHORT TERM CYCLOGENESIS. ERN CANADIAN VORTEX IN MID LVLS IS KEEPING SRN BRANCH OF JET STREAM DISPLACED TO THE SOUTH. NO SIGNIFICANT CHANGE OCCURS UNTIL MIDWEEK WHEN ERN VORTEX MOVES EAST AND HT RISES DEVELOP OVER NRN PLAINS. AT SFC... LARGE ANTICYCLONE WILL PREVAIL THROUGH EARLY WEDNESDAY. WITH LACK OF APPRECIABLE SYNOPTIC SCALE FORCING AND LOW PWATS.. SHOULD HAVE LITTLE CLOUDS/PRECIP THROUGH MON/TUE. BY WEDNESDAY...MID LVL SHORTWAVE TROF MAY APPROACH AND COMBINED WITH LOW LEVEL WARM ADVECTION POPS MAY TREND HIGHER OVER NEXT FEW MDL CYCLES. WILL LEAVE FCST DRY AT THIS TIME ALTHOUGH GFS/SREF SUGGEST WRN CWA MAY HAVE MEASUREABLE. GFS IS BIASED WITH REGARD TO TRACE AMOUNTS AND THE PROB OF GEFS PRECIP GREATER THAN .05" IS VERY LOW. EC IS DRY AND WILL LEAN WITH THIS IDEA FOR NOW. TRIMMED PREVIOUS GRIDS BACK ON CLOUD AMOUNTS AND LOWERED SOME OVERNIGHT MIN TEMPS WITH PERSISTENCE MAINTAINING SOME CHILLY OVERNIGHT READINGS. MAX TEMPS STILL BELOW NORMAL RANGE UNTIL WED. EXTENDED...WEDNESDAY NIGHT THROUGH SUNDAY UPPER FLOW WILL FEATURE FAST FLOW COMING ONTO THE PACIFIC NORTHWEST/BRITISH COLUMBIA COAST THROUGH FRIDAY...WITH A TROUGH DEVELOPING TOWARD/OVER THE WEEKEND ALONG THE WEST COAST. AN UPPER TROUGH WILL BE OVER/NEAR THE NORTHLAND WEDNESDAY...WITH A COUPLE DIFFERENT SHORTWAVES MOVING THROUGH. WE CONTINUED OUR POPS FOR THURSDAY THROUGH FRIDAY NIGHT. LOW LEVEL TEMPERATURES WOULD DICTATE A MIX OF PRECIP TYPES WILL BE POSSIBLE. BRIEF RIDGING SATURDAY SHOULD DRY WEATHER. THE 12Z ECMWF HAS CHANGED QUITE A BIT FROM IT'S 00Z RUN...AND ALSO DIFFERS FROM THE GFS. PREVIOUSLY...BOTH MODELS HAD A LOW IN THE CENTRAL/SOUTHERN PLANS BY SUNDAY...WITH PRECIP WELL TO THE NORTH OVER THE NORTHLAND ASSOCIATED WITH AN UPPER WAVE AND TIGHT THERMAL GRADIENT. NOW...THE ECMWF IS SLOWER DUE TO IT CLOSING OFF THE UPPER LOW OFF THE SOUTHWEST CA/BAJA REGION. WE HAVE SOME POPS GOING FOR SUNDAY...AND COULD SEE A RAIN/SNOW MIX OVER PORTIONS OF THE NORTHLAND. NO REAL BIG WARM-UP EXPECTED THROUGH THE EXTENDED...GENERALLY HIGHS SHOULD BE IN THE FORTIES WITH LOWS TWENTY TO THIRTY. && .POINT TEMPS/POPS... DLH 2 33 11 37 / 0 0 0 0 INL 1 32 2 38 / 0 0 0 10 BRD 3 36 11 38 / 0 0 0 10 HYR -1 39 8 39 / 0 0 0 0 ASX 5 37 9 37 / 0 0 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...LAMERS  FXUS63 KDLH 070824 AFDDLH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 324 AM CDT THU APR 7 2011 .DISCUSSION... .SHORT TERM.../TODAY THROUGH FRIDAY/... IN THE VERY NEAR TERM...KEPT PATCHY DENSE FOG WORDING NEAR THE HEAD OF LAKE SUPERIOR UNTIL 14Z AS OBS AND 11-3.9 MICRON SATELLITE PRODUCT SHOW PERSISTENCE OF AN AREA OF FOG AND LOW STRATUS. A FEW OBS HAVE BEEN DOWN TO 1/4SM. FOCUS THEN TURNS TO WEAK SHORTWAVE THAT SHOULD BRUSH THE NORTHWEST PART OF THE CWA AS IT ROUNDS THE PERIPHERY OF AN EXPANSIVE UPPER LEVEL RIDGE. THIS FEATURE IS EVIDENT IN WATER VAPOR LOOP OVER ERN MT CURRENTLY. LINEAR EXTRAPOLATION BRINGS THE COOLER CLOUD TOPS ON IR SAT INTO NWRN CWA AROUND 18Z TODAY. GENERALLY FOLLOWED THIS TIMING IN SKY/POP FIELDS OVER NEXT 12-18HRS AS IT MATCHED WELL WITH SIMULATED SATELLITE FIELDS FROM NAM AND UW-CRAS MODELS. INTRODUCED SOME LOW CHC POPS FAR NW. LLVL WAA AND FGEN ARE FAIRLY IMPRESSIVE FOR SUCH A WEAK SHORTWAVE AND LATEST 4KM WRF NMM SHOWS SOME HEAVIER SHOWERS IMPACTING FAR N/NW MN LATER TODAY. EARLY SIGNALS ARE THAT THIS NARROW BAND OF FORCING MAY BE SETTING UP NEAR ND-SD BORDER NOW WITH SOME RW AND EVEN A CG LTNG STRIKE. AN ENE TRAJECTORY OF THIS AREA OF FORCING WOULD CLIP MOSTLY NRN ITASCA...KOOCHICHING...AND NRN ST. LOUIS COUNTIES. ALL MODELS DRY THINGS OUT ON FRIDAY...SO WE CUT OUT THE POPS DURING THE DAYTIME. IT SHOULD BE A WARM COUPLE DAYS ACROSS THE AREA BUT LOCATION OF DENSER CLOUD COVER WILL BE THE KEY. OVERALL IT APPEARS AS THERE SHOULD BE A MIX OF CLOUDS AND SUN BOTH DAYS BUT THE BEST CHANCE OF LESS CLOUDS LOOKS TO BE FURTHER SOUTH. BOTH MET AND MAV MOS HAVE HIGHS IN THE LOW-MID 60S IN THESE AREAS THU AND FRI. THIS ACTUALLY LINES UP WELL WITH WHAT YOU WOULD GET MIXING DRY ADIABATICALLY UP TO 850MB DURING THE AFTN BASED ON THE CONSENSUS 850MB TEMPS. BASICALLY...IF IT GETS SUNNY DURING THE NEXT TWO DAYS...HIGHS ARE LIKELY TO BE ON THE UPPER END OF THE GUIDANCE ENVELOPE. THIS WAS ACCOUNTED FOR BY BUMPING HIGHS ESPECIALLY ACROSS THE SOUTH. .EXTENDED.../FRIDAY NIGHT THROUGH WEDNESDAY/... EARLY PART OF THE EXTENDED PERIOD IS CHARACTERIZED BY A RIDGE OF HIGH PRESSURE ALOFT THROUGH THE MID SECTION OF THE COUNTRY...AND A WEAK SFC BOUNDARY SKIRTING THE NRN EDGE OF THE RIDGE ALONG THE INTERNATIONAL BORDER. THIS BOUNDARY COULD POSSIBLY SLIDE ENOUGH TO THE EAST AND SOUTH TO BRING SOME LIGHT RAIN SHOWERS TO THE WRN PARTS OF THE FORECAST AREA...OTHERWISE MOST AREAS WILL BE DRY UNTIL SATURDAY AFTERNOON...WHEN SOME CONVECTIVE SHOWERS COULD DEVELOP FROM WEST TO EAST OVER THE NORTHLAND. KEPT A MENTION OF THUNDER FOR MAINLY THE SRN HALF OF THE CWA SAT NIGHT AND SUN MORNING. WILL BE MAINLY ELEVATED CONVECTION...WITH STEEP MID-LEVEL LAPSE RATES ABOVE A SFC/LOW-LVL INVERSION...ACCORDING TO BOTH NAM AND GFS BUFR SOUNDINGS. WILL SEE SHOWERS LIKELY THROUGH THE DAY SUNDAY...WITH A CHANCE OF THUNDERSTORMS AS WELL...MAINLY OVER THE WI COUNTIES AS THE AREA OF LOW PRESSURE TRACKS THROUGH THE MID MS VALLEY. THE INSTABILITY AXIS SHIFTS WELL TO THE EAST BY MONDAY...BUT THE NORTHLAND COULD STILL SEE LINGERING SHOWERS THROUGH LATE MORNING MON. BY LATE IN THE DAY MONDAY AND THROUGH TUESDAY...CONDITIONS SHOULD BEGIN TO DRY OUT AS A SFC RIDGE BUILDS IN BEHIND THE DEPARTING SYSTEM. THE TIMING OF THE FOLLOWING WEAK WAVE IS STILL IN QUESTION AMONG THE VARIOUS MODELS...SO JUST WENT WITH SLIGHT CHC POPS GOING INTO WEDNESDAY. TEMPERATURES WILL BE AT OR SLIGHTLY ABOVE NORMAL DURING THE PERIOD WITH HIGHS IN THE UPPER 40S AND LOWER 50S...AND LOWS IN THE 40S THIS WEEKEND AND THE 30S BY THE EARLY PART OF NEXT WEEK. && .PREV DISCUSSION... /ISSUED 1242 AM CDT THU APR 7 2011/ AVIATION.../06Z TAF ISSUANCE/ LIFR CIGS AT THE HEAD OF LAKE SUPERIOR MAY MOVE BACK IN AT DLH UNTIL 10Z. HAVE TEMPO GROUPS BEFORE SUNRISE FOR HIB...HYR AND BRD. SHOWERS MAY BRUSH INL BY THURSDAY EVENING...OTHERWISE VFR THROUGH THE TAF FORECAST PERIOD. && .POINT TEMPS/POPS... DLH 53 33 50 40 / 10 10 10 10 INL 50 33 53 38 / 30 40 10 20 BRD 61 37 58 40 / 10 10 10 10 HYR 57 36 58 40 / 10 10 10 10 ASX 55 35 51 42 / 10 10 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...LAMERS EXTENDED....TENTINGER AVIATION....KK  FXUS63 KDLH 110805 AFDDLH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 305 AM CDT SAT JUN 11 2011 .DISCUSSION...TODAY THROUGH SUNDAY. MID TO UPPER LEVEL LOW EVIDENT ON WATER VAPOR LOOPS WAS CROSSING FROM C MN INTO N WI AROUND 0730Z. QG FORCING ANALYSIS SUGGESTS BROAD AND DEEP SUBSIDENCE WILL QUICKLY SPREAD OVER THE CWA IN THE WAKE OF THE DEPARTING TROUGH BETWEEN 09Z AND 15Z. THIS WILL ALLOW CLOUDS TO CLEAR THE AREA FROM NW TO SE AND FOR ANY LINGERING RAIN SHOWERS TO COME TO AN END. IN GENERAL...11.00Z UW-CRAS MODEL SIMULATED CLOUD COVER AND IR SATELLITE PRODUCTS SEEMED TO HAVE A GOOD HANDLE ON THE TRENDS...SO THAT WAS FOLLOWED. DESPITE SUBSIDENCE REGIME...SOME MODELS HAVE SOME SPOTTY QPF ON THE ORDER OF 0.01-0.03 INCHES LATE THIS AFTERNOON ACROSS INTERIOR MN ZONES NORTH OF HWY 2. THIS SEEMS TO BE ASSOCIATED WITH WEAK LOW-LEVEL CONVERGENCE ALONG A SUBTLE SFC PRESSURE TROUGH. LOCAL DLH-WRF DEVELOPS SHOWERS JUST NORTH OF THE CANADIAN BORDER AND THEN SPREADS THEM INTO NRN MN AFTER 18Z. WE FELT THIS WAS WORTH 15-20 PCT POP. SMALL POSITIVE BUOYANCY REGION ON FCST SOUNDINGS DOES NOT EXTEND ABOVE -15C...SO PROSPECTS OF THUNDER SEEM LOW. THERE WILL BE A FEW POSSIBLE ISSUES TO DEAL WITH TONIGHT. THE FIRST IS LOW TEMPERATURES AND THE POTENTIAL FOR SOME PATCHY FROST. THE CLEARING SKIES AND SFC ANTICYCLONE CERTAINLY ARGUE FOR QUICKLY PLUMMETING TEMPS IN THE EVENING. HOWEVER...MODELS ALSO SHOW THAT THE 925-850MB LAYER LOCKED IN A WEAK WAA PATTERN ALL NIGHT. GIVEN THE OPPOSING IDEAS...FOLLOWED CONSENSUS GUIDANCE CLOSELY WITH A FEW COOLER TWEAKS IN THE TYPICAL COLD SPOTS. IT SHOULD BE NOTED THAT THE GFS LAMP MOS PUTS HYR AND IWD IN THE 36-38F RANGE BY 08Z. WILL LET THE DAY SHIFT EVALUATE THE TRENDS IN THE LOW LEVEL THERMAL STRUCTURE AND CLOUD DISTRIBUTION TO MAKE THE CALL ON ANY LOWER TEMPS OR FROST. THE OTHER ISSUE IS THE POSSIBILITY OF SOME FOG. CROSSOVER TECHNIQUE IS NOT QUITE IN FOG RANGE ON BUFR SOUNDINGS...BUT WITH LIGHT WINDS THIS WILL NEED TO BE MONITORED AS WELL. SUNDAY IS SHAPING UP TO BE A PLEASANT DAY WEATHER-WISE. WITH RIDGE AXIS KEEPING ANY PRECIP CHANCES WELL WEST...IT SHOULD BE DRY AND WARMER. MIXING AFTN 850MB AND 925MB TEMPS ON THE NAM AND GFS DRY ADIABATICALLY TO THE SURFACE YIELDS SOME AREAS OF MID-UPR 70S. MET AND MAV MOS FIGURES ARE BOTH IN THE MID 70S IN MOST AREAS AWAY FROM THE LAKE...SO HIGH TEMPS WERE BOOSTED. .EXTENDED...SUNDAY NIGHT THROUGH FRIDAY. A SHORTWAVE RIDGE WILL PASSING THROUGH THE REGION EARLY IN THE PERIOD...WITH A DEEPENING TROUGH REPLACING THE RIDGE. INCREASING WAA/MOISTURE TRANSPORT AHEAD OF THE APPROACHING TROUGH WILL BRING A CHANCE FOR SHOWERS TO MAINLY OUR FAR WESTERN ZONES SUNDAY NIGHT. THE ECMWF SHOWS SURFACE RIDGING AT THE SURFACE OVER OUR CWA INTO MONDAY NIGHT...BEING DISPLACED LATER TUESDAY. THIS HIGH SHOULD KEEP BETTER CHANCES FOR RAIN OVER OUR WESTERN CWA THROUGH MONDAY NIGHT. ECMWF/GEM IN GENERAL AGREEMENT DEVELOPING A STRONGER SHORTWAVE/SURFACE LOW FOR THE TUESDAY-WEDNESDAY NIGHT PERIOD AS COMPARED TO THE GFS. A CHANCE FOR SHOWERS/STORMS WILL EXIST THROUGH THAT PERIOD OVER MUCH OF THE CWA. ANOTHER TROUGH WILL BRING A CHANCE FOR MORE RAIN LATE IN THE PERIOD. OVERALL...OUTSIDE OF LAKE BREEZES AND ANY STEADIER RAIN AREAS...TEMPERATURES THROUGH MUCH OF THE EXTENDED WILL BE SEASONABLE. && .AVIATION.../06Z TAF ISSUANCE/ CEILINGS AROUND 2500 FT..WITH LOCALIZED IFR CONDITIONS...WERE FOUND OVER NRN WISCONSIN...EXTENDING NORTH OVER LAKE LAKE SUPERIOR. THE MVFR CIGS WILL PERSIST IN THIS AREA THROUGH 12Z...AFFECTING THE KHYR AND KDLH TAF SITES. ELSEWHERE...VFR CONDITIONS WITH MID TO HIGH CLOUD DECKS WILL PREVAIL WITH AN ISOLD SHRA POSSIBLE OVERNIGHT. CEILINGS AROUND 5 KFT WILL SCATTER FROM NORTHWEST TO SOUTHEAST THROUGH SAT MORNING...CLEARING SAT EVENING. && .POINT TEMPS/POPS... DLH 61 45 69 50 / 10 10 0 10 INL 70 42 75 56 / 20 20 10 20 BRD 70 47 72 55 / 10 0 10 20 HYR 64 40 74 51 / 10 0 0 10 ASX 60 40 69 48 / 10 10 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...LAMERS EXTENDED....MELDE AVIATION...GRANING