FXUS63 KDLH 091205 AAA
AFDDLH
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
605 AM CST WED DEC 9 2009
.UPDATE...DISCUSSION FOR 12 Z TAFS...
&&
.AVIATION.../12Z TAF ISSUANCE/...
MVFR CEILINGS WITH MVFR/IFR VSBYS WILL BE FOUND IN -SN/BLSN TODAY.
CIGS WILL JUMP TO VFR FOR A TIME AT THE WESTERN TERMINALS
KBRD/KINL/KHIB THIS MORNING WITH MVFR MIXED IN. KDLH AND
ESPECIALLY KHYR WILL SEE IFR VSBYS WITH BLSN WHERE MORE SNOW HAS
ACCUMULATED AND THE STRONGER PRESSURE GRADIENT EXISTS. EXPECT BLSN
TO CONTINUE WITH INCREASING NNW WINDS BEFORE THE GRADIENT BEGINS
TO SLACKEN TONIGHT. ALL TERMINALS LIFT TO VFR BY THE END OF THE
PERIOD WITH A WEAK HIGH PRESSURE RIDGE BUILDING INTO THE WEST.
&&
.PREV DISCUSSION... /ISSUED 436 AM CST WED DEC 9 2009/
DISCUSSION...WINTER STORM REMAINS THE MAIN SHORT TERM FOCUS. THE
FOCUS WILL THEN SHIFT TO WIND CHILL HEADLINE POTENTIAL.
AT 330 AM...DULUTH RADAR SHOWED A COUPLE BANDS OF HEAVY SNOW
ACROSS MAINLY NW WI. THERE WERE ALREADY SOME 9 INCH AMOUNTS AS OF
LATE EVENING IN THE BAYFIELD PENINSULA AREA...WITH HEAVY SNOW
CONTINUING SINCE THAT REPORT AS WELL. THE REST OF THE AREA WAS
SEEING BANDS OF MAINLY LIGHT BUT PERSISTENT SNOW...WHICH HAVE BEEN
GRADUALLY ADDING UP OVER TIME.
THE 00Z AND 06Z MODELS ARE IN RELATIVELY GOOD AGREEMENT THIS
MORNING...BRINGING THE CENTER OF THE SURFACE LOW TO SOUTHERN LAKE
MICHIGAN BY 12Z THIS MORNING. THEY ALSO BRING THE SURFACE LOW TO
LAKE HURON BY 00Z THIS EVENING. SO TIMING AND THE STRENGTH OF
SYNOPTIC SCALE DETAILS ARE FAIRLY CONSISTENT.
THE OBVIOUS FOCUS FOR TODAY REMAINS NORTHWESTERN WISCONSIN...WHICH
SHOULD SEE THE BRUNT OF THIS STORM. THE BANDS MOVING ACROSS NW WI
THIS MORNING ARE QUITE IMPRESSIVE...AND WILL INCREASE AMOUNTS A
TAD TO 12 TO 20 INCHES ACROSS THE SOUTH SHORE. WOULD NOT BE
TOTALLY SURPRISED TO SEE A REPORT TOPPING 20 INCHES IN THE
BAYFIELD PENINSULA...OR EVENTUALLY ON THE GOGEBIC RANGE. THINK
AMOUNTS WILL BE HIGHLY VARIABLE ACROSS THE AREA.
THE AREAS FURTHER WEST WERE MUCH MORE TRICKY THIS MORNING.
CONTEMPLATED CHANGING THE WINTER STORM WARNING FOR EC MN INTO THE
NORTH SHORE TO A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING
SNOW...BUT HAVE DECIDED TO HOLD OFF FOR NOW. WILL BACK OFF A BIT
ON THE SNOW AMOUNTS...TO A TOTAL SNOW ACCUMULATION OF 4 TO 7
INCHES. SNOWFALL REPORTS RECEIVED SO FAR ARE STILL PRETTY LIMITED...
BUT GENERALLY 2 INCHES OR LESS AS OF 4 AM. BANDS OF SNOW WRAPPING
WESTWARD ACROSS THE LAKE WILL STILL BRING SOME PERSISTENT AND
GRADUALLY ACCUMULATING SNOW TO THE EC MN/NORTH SHORE AREA. DID NOT
WANT TO TAKE THE WARNING DOWN JUST YET...AS THE BANDS HAVE BEEN
ORGANIZING A BIT MORE OVER THE PAST HOUR OR TWO WITH BETTER
DENDRITIC SNOW AT THE TIME. STILL THINK IT MAY BE TOUGH TO GET THE
HIGHER AMOUNTS...BUT WILL LEAVE AS A WARNING FOR NOW.
AREAS FURTHER WEST WILL SEE EVEN LESS SNOW...BUT WILL CONTINUE TO
HAVE PROBLEMS WITH SNOW AND BLOWING SNOW THROUGHOUT THE DAY.
AMOUNTS IN THE FAR NW PORTION OF THE CWA LOOK PRETTY LIMITED...BUT
MAYBE AN INCH OR SO.
LAKE EFFECT AND/OR LAKE ENHANCED SNOW WILL CONTINUE ACROSS THE
SOUTH SHORE TONIGHT...WITH SNOW DIMINISHING MOST ELSEWHERE. THE
BIG STORY STARTING TONIGHT WILL BE THE POTENTIAL FOR WIND CHILL
ADVISORIES. WITH CURRENT WINTER WEATHER HEADLINES...DID NOT WANT
TO INITIATE ANOTHER HEADLINE AT THIS POINT...BUT THINK A HEADLINE
WILL BE IN ORDER FOR LATER FORECASTS. CURRENT ZONES/GRIDS HAVE THE
WIND CHILL VALUES HIGHLIGHTED...AND WILL HIT IT HARD IN THE HWO.
THE PRECIPITATION WILL DIMINISH EVEN FURTHER ON THURSDAY...
ALTHOUGH IT MAY LINGER IN PORTIONS OF THE EAST AND SOUTH SHORE.
WINDS SHIFTING TO THE WEST WILL MEAN A GRADUAL END TO THE LAKE
EFFECT ON THE SOUTH SHORE.
EXTENDED...THURSDAY NIGHT THROUGH MONDAY NIGHT...
ON THURSDAY NIGHT INTO FRIDAY MORNING...EXTENSION OF THE VORT MAX
IN COLD POLAR VORTEX MOVES THROUGH THE BORDERLAND. THE NAM/GFS ARE
STRONGER WITH THE UPPER LEVEL ENERGY...THE ECMWF WEAKER.
REGARDLESS...WEAK SURFACE REFLECTION EXISTS SOUTH OF THE
INTERNATIONAL BORDER AND SCANT MOISTURE WILL KEEP A FEW FLURRIES
ALONG THE BORDERLAND.
SURFACE HIGH PRESSURE BUILDS IN FRIDAY NIGHT AS THE UPPER LOW PIVOTS
AND REMAINS IN CENTRAL SK/MB. MODEL DIFFERENCES BECOME MORE
PREVALENT SATURDAY MORNING AS THE 12Z ECMWF DEVELOPS AN INVERTED
TROUGH OVER NORTH DAKOTA...WHILE THE GFS DIGS A WEAK SURFACE LOW
MUCH FURTHER SOUTH. HPC PREFERS THE QUICKER NAM/GEM. THE GFS APPEARS
TO BE AN OUTLIER WITH REGARDS TO ITS HANDLING OF THE UPPER LOW/POLAR
VORTEX ALSO. BEST ISENTROPIC LIFT/LOWER LEVEL SATURATION WILL AGAIN
REMAIN NORTH OF THE BORDER...BUT WE HAVE CONTINUED THE LOW CHC POPS
ALONG THE BORDERLAND WITH THE THERMAL GRADIENT IN PLACE.
THE POLAR VORTEX IN SK WILL FINALLY GET SHOVED EAST AS THE NORTHERN
STREAM UPPER LEVEL JET DIGS ALONG THE BASE OF THE LOW AND FINALLY
PROVIDES THE MOMENTUM TO GET IT MOVING. FOLLOWING THE GEM/ECMWF...
THE COLD CORE WILL MOVE THROUGH SOUTH CENTRAL CANADA...AND THE
SOUTHERN EXTENT OF THE UPPER TROUGH WILL PUSH A COLD FRONT THROUGH
ON SATURDAY NIGHT AND SUNDAY. WITHOUT GOING INTO THE DETAILS...THE
GFS IS MUCH WARMER. WE HAVE CONTINUED THE SLIGHT CHANCE OF LIGHT
SNOW ACROSS THE NORTHLAND ON SATURDAY...AND EXTENDED THE CHANCE INTO
FAR EASTERN MN AND NW WISC WITH THE PRESENCE OF THE THERMAL
BOUNDARY. UNCERTAINTY EXISTS IN RECENT MODEL RUNS WITH REGARDS TO
WHETHER OR NOT THE FRONT WILL PUSH THROUGH THE AREA COMPLETELY. THIS
WILL MAKE SATURDAY PM/SUNDAY FCST OF TEMPS/WINDS A BIT TRICKY...AND
MUCH LOWER CONFIDENCE DUE TO HIGH UNCERTAINTY IN THIS PERIOD. HAVE
REMAINED ON THE COOL SIDE OF MEDIUM RANGE GUIDANCE AT THIS TIME.
SIGNIFICANT MODEL DISCREPANCIES EXIST REGARDING THE SUNDAY
NIGHT/MONDAY TIME FRAME...WITH A FAST MOVING SHORTWAVE MOVING
THROUGH THE CENTRAL PLAINS ALONG THE SOUTHERN STREAM JET.
TIMING/LOCATION ISSUES EXISTS REGARDING THE SURFACE REFLECTION...SO
LITTLE CHANGES TO THE GRIDS HAVE BEEN MADE...THOUGH SOME POPS MAY
NEED TO BE ADDED IN THESE PERIODS. ANOTHER COLD SHOT COMES ON
TUESDAY.
&&
.POINT TEMPS/POPS...
DLH 11 -6 7 -5 / 100 40 10 10
INL 3 -14 1 -12 / 60 10 10 10
BRD 7 -10 6 -9 / 80 10 10 10
HYR 17 -4 5 -8 / 100 40 10 10
ASX 20 3 8 -3 / 100 70 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ012-
019-034>036.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ020-021-
037-038.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR WIZ006>009.
WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR WIZ001>004.
LS...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST THURSDAY
FOR LSZ121-140>148.
GALE WARNING UNTIL 6 PM CST THIS EVENING FOR LSZ121-140>148.
&&
$$
SHORT TERM: DAP
EXTENDED/AVIATION: DONOFRIO
