FXUS63 KDLH 012111
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
311 PM CST TUE DEC 1 2009
.DISCUSSION...SFC LOW CENTER AT 20Z WAS MOVING THROUGH NORTHERN
CASS COUNTY IN WESTERN FA. A WARM FRONT EXTENDED E THROUGH NW WI
WITH AN INVERTED TROF BACK INTO NW MN/NE ND. AN OCCLUDED FRONT
EXTENDED S THROUGH CENTRAL MN. VERY FEW CLOUDS ACROSS THE SE PART
OF THE FA ATTM. WITH MORE SUNSHINE...THIS ALLOWED MAX TEMPS TO
REACH INTO THE 40S ACROSS THE SOUTHERN COUNTIES. CLOUDS/SNOW HAVE
KEPT TO THE NORTHERN PART OF THE AREA WITH ACCUMULATING SNOW N OF
THE IRON RANGE...PRIMARILY NEAR THE CANADIAN BORDER.
EXPECT THE SFC LOW TO CONTINUE TO MOVE EASTWARD TONIGHT AND BE OVER
EASTERN LAKE SUPERIOR BY 12Z WEDNESDAY. RADAR TRENDS INDICATE TWO
PERIODS OF SNOW. THE FIRST IS ENDING ATTM OVER THE FA WITH A SECOND
SWATH IN NW MN. THIS NEXT PERIOD OF SNOW WILL NOT PRODUCE THE
ACCUMULATIONS AS THE FIRST ONE. FGEN FROM ALL MODELS EXITS THE TIP
OF THE MN ARROWHEAD BY 03Z WEDNESDAY. WILL ADJUST THE END TIME TO
THE ADVISORY TO 04Z/10 PM TO ACCOUNT FOR ANY LINGERING SNOW. NOT
EXPECTING THE HIGHER WIND GUSTS TONIGHT AS WIND TO 925MB AT 20 TO 25
KT AT BEST INTO WEDNESDAY AND HAVE LOWERED THE GUSTS.
FA IS UNDER CYCLONIC FLOW ALOFT INTO FRIDAY AND LOW POPS WARRANTED.
LES ALONG THE SOUTH SHORE OF LAKE SUPERIOR WEDNESDAY THROUGH
THURSDAY NIGHT WITH NW FLOW/CAA/FAVORABLE DELTA T/S. THE LES WILL
END BY 12Z FRIDAY AS FLOW BECOMES WESTERLY.
.EXTENDED...FRIDAY NIGHT THROUGH TUESDAY...
FOLLOWED THE ECMWF FOR MUCH OF THE EXTENDED PERIOD DUE TO ITS GOOD
RUN TO RUN CONTINUITY AND CONSISTENCY WITH ITS ENSEMBLE MEAN MEMBERS
WITH REGARDS TO THE DEEP UPPER LEVEL TROF OVER THE CENTRAL/EASTERN
CONUS. THE BEGINNING OF THE EXTENDED PERIOD WILL FIND THE UPPER
LEVEL LOW RETROGRADING A BIT BACK TO THE WEST. PIECES OF ENERGY WILL
THEREFORE CONTINUE TO SWING SOUTH ON THE BACK SIDE OF THE LOW
BEFORE IT THEN PULLS OFF TO THE EAST WITH THE NORTHERN STREAM JET
ENERGY. THIS WILL KEEP THE CHANCE OF SNOW SHOWERS ACROSS THE AREA ON
SATURDAY. WE HAVE ADDED SOME SLIGHT CHC POPS TO ACCOUNT FOR THIS ON
SATURDAY...ESPECIALLY NORTH.
THE BEGINNING OF THE PERIOD WILL FIND THE FIRST PHASE OF WINDING
DOWN THE LAKE EFFECT MACHINE...AS WINDS ALONG THE SOUTH SHORE BECOME
WEST AND EVEN SOUTHWEST...BUT THEN THE MACHINE WILL GET BACK STARTED
ON SUNDAY AND MONDAY AS WINDS BECOME N/NW AGAIN.
HIGH PRESSURE WILL PUSH INTO THE AREA ON SUNDAY. WINDS WILL REMAIN
GENERALLY NORTHERLY...KEEPING THE COLDER AIR PARKED OVER THE AREA. HIGH
TEMPS WILL NOT CHANGE MUCH EACH DAY...WITH LITTLE ADDITIONAL
TEMPERATURE ADVECTION AFTER THE MAIN PLUNGE EARLIER IN THE WEEK. 850
TEMPS LINGER IN THE MID TEENS BELOW WHICH WILL MEAN HIGHS IN THE
20S...LOWS IN THE TEENS WITH A FEW SINGLE DIGITS ALONG THE RANGE AND
ARROWHEAD. CLOUD COVER WILL LIMIT A DIVE OF TEMPERATURES
OVERNIGHT.
&&
.AVIATION...18Z TAFS.
IFR/LIFR CONDITIONS WILL BE FOUND IN SNOW AT KINL AS A
STRONG LOW PRESSURE SYSTEM PUSHES EAST THROUGH THE HEART OF THE
NORTHLAND. EXPECT KHIB TO DROP TO MVFR/IFR LATER IN THE AFTERNOON
ONCE THE LOWER LAYERS SATURATE AND BETTER LIFT APPROACHES. THE
SOUTHERN TERMINALS WILL REMAIN ON THE SOUTHERN END OF THE BETTER
FORCING...BUT MVFR JUST AHEAD OF AND BEHIND THE SURFACE LOW WILL
SPREAD MVFR CONDITIONS EASTWARD AFTER A PERIOD OF VFR IN THE
AFTERNOON...AFFECTING KHYR LATEST. EXPECT MVFR STRATUS AND GUSTY
WEST/NORTHWEST WINDS ON THE BACK SIDE OF THE LOW WITH STRONG
PRESSURE RISES LEADING TO ISALLOBARIC ACCELERATION.
&&
.POINT TEMPS/POPS...
DLH 23 30 16 21 / 70 10 10 20
INL 17 27 12 16 / 60 10 10 20
BRD 24 32 18 21 / 30 10 10 20
HYR 24 32 17 22 / 10 20 30 20
ASX 24 33 19 24 / 30 20 40 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 10 PM CST THIS EVENING FOR
MNZ010>012-018-019-021.
WI...NONE.
LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM CST
THURSDAY FOR LSZ121-146>148.
SMALL CRAFT ADVISORY UNTIL 4 PM CST WEDNESDAY FOR LSZ142>145.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM CST
WEDNESDAY FOR LSZ140-141.
&&
$$
GSF/DONOFRIO
