FXUS63 KDLH 251738
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1138 AM CST WED NOV 25 2009
.UPDATE...MID LVL LOW OVER NRN LK MI LATE THIS MORNING WITH AN
ELONGATED SHEAR ZONE STRETCHING WES TOWARDS KDLH. ALONG THIS
CONVERGENCE AXIS AN ARE OF HEAVIER PRECIP HAS DEVELOPED OVER CTRL
SAWYER COUNTY. KHYR REPORTING CHANGE TO SNOW...MOST LIKELY A
RESULT OF BRIEF ELIMINATION OF WARM NEAR SFC LAYER BY DIABATIC
COOLING. EXPECT THIS TO BE A BRIEF PTYPE AT KHYR AS FLOW IS STRONG
ENOUGH TO KEEP AREA OF FORCING/PRECIP MOVING. OTHERWISE GRIDS/ZFP
IN DECENT SHAPE. SYNOPTIC SCALE PATTERN FEATURES A FAVORABLE
BACKGROUND FOR SOME LAKE ENHANCED SNOW OVER GOGEBIC RANGE. MAY
NEED TO SHUT OFF LAKE SNOW EARLIER THURSDAY IF FCST 85/70H LAYER
MOISTURE LOWERS AS QUICKLY AS SOME OF THE MDL GUIDANCE. WILL LEAVE
FOR NOW AS BETTER BDRY LYR LAPSE RATES/INSTABILITY OCCURS AFTER
DEPARTURE OF DEEPER MOIST COLUMN TOMORROW AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 618 AM CST WED NOV 25 2009/
AVIATION...12Z TAFS.
MVFR WITH AREAS OF VFR FROM KBRD TO KINL THROUGH 16-18Z TIME FRAME
AS COLD AIR CHANGES PCPN OVER TO -SN. AFTER 18Z...KINL/KBRD
EXPECTED TO BECOME VFR AS HIGH PRESSURE APPROACHES FROM THE WEST.
KHIB/KDLH/KHYR CLOSER TO THE LEADING COLD FRONT SLOWLY EXITING MN
INTO WI AT 12Z. MAINLY IFR CONDITIONS...OCCASIONALLY MVFR...NEAR
THIS FRONT WITH PCPN TYPE BEING PRIMARILY -RA. HOWEVER...THE -RA
WILL MIX WITH THEN CHANGE TO -SN THROUGH THE DAY AS COLDER AIR
FILTERS IN FROM THE SFC HIGH ARRIVING. -DZ/BR ALSO EXPECTED AHEAD
OF THE COLD FRONT THIS MORNING. LOOK FOR CONDITIONS TO IMPROVE TO
VFR IN THE 03-06Z RANGE.
PREV DISCUSSION... /ISSUED 406 AM CST WED NOV 25 2009/
DISCUSSION...LATEST SFC ANALYSIS SHOWS A COLD FRONT EXTENDING
FROM THE ARROWHEAD OF MN SOUTH OVER WRN LAKE SUPERIOR AND NWRN
WI. AN AREA OF RAIN HAS BECOME MORE ORGANIZED INVOF THE FRONT
ACROSS OUR ERN ZONES EARLY THIS MORNING. FARTHER WEST...COLDER AIR
HAS MOVED IN ACROSS OUR WESTERN ZONES WITH TEMPS CURRENTLY IN THE
UPPER 20S AND LOWER 30S. AREAS OF FOG WILL LINGER ACROSS THE CWA
THROUGH THIS MORNING DUE TO ABUNDANT LOW-LEVEL MOISTURE ASSOCIATED
WITH THE FRONT.
THE RAIN WILL GRADUALLY SPREAD ACROSS ALL OF NWRN WI TODAY...WHILE
ENDING ACROSS THE ARROWHEAD REGION. WITH COLDER AIR ADVECTING IN
FROM THE WEST AND NORTH...SOME OF THE PRECIP ACROSS OUR MN ZONES
MAY MIX WITH OR CHANGE OVER TO LIGHT SNOW TODAY. BY TONIGHT...ANY
PRECIP SHOULD BE IN THE FORM OF SNOW...EXCEPT ACROSS NWRN WI THIS
EVENING WHERE A MIX OF RAIN AND SNOW IS EXPECTED. THE BEST CHANCE
FOR PRECIPITATION WILL BE ACROSS THE SNOWBELT OF NWRN WI WHERE
LAKE EFFECT/ENHANCEMENT AND OROGRAPHIC LIFT WILL AID IN THE
DEVELOPMENT OF PRECIP. ELSEWHERE CONDITIONS WILL BE MOSTLY DRY AND
COLD TONIGHT AND TOMORROW AS HIGH PRESSURE BUILDS IN OVER THE
MIDWEST. THE LAKE EFFECT SNOW WILL TAPER OFF ON THURSDAY...AND
SHOULD END BY EARLY THURSDAY EVENING.
EXTENDED...THURSDAY NIGHT THROUGH TUESDAY.
SFC RIDGING WILL COVER THE FA THURSDAY NIGHT THROUGH SATURDAY. EVEN
THOUGH AN UPPER LEVEL SHORT WAVE WILL CROSS SOUTHERN CANADA NEAR THE
MN BORDER...THE BULK OF THE LIFT WILL REMAIN N OF THE BORDER.
SATURDAY NIGHT AND SUNDAY THE MODELS BEGIN TO DIVERGE IN THEIR
SOLUTIONS AND HOW THE FA IS AFFECTED. 00Z/25 ECMWF AGREES WITH
CANADIAN GLOBAL THAT PCPN WILL BE FOUND ACROSS THE NORTHERN HALF OF
THE FA AND HAVE FOLLOWED ITS SOLUTIONS. REST OF THE FORECAST
UNCHANGED.
AVIATION.../06Z TAF ISSUANCE/
WIDE RANGE OF CONDITIONS EXPECTED THRU THE TAF PD. WHERE CLEARING
LINE HAS MOVED IN FROM THE WEST...VSBYS HAVE DROPPED DOWN IN FG.
EXPECT THIS TO LIFT BY DAYBREAK AS HIGHER CLDS AND DRIER AIR MOVE
IN. ELSWHERE...IFR/MVFR CIGS HAVE BEEN MORE OR LESS STEADY
STATE...BUT VSBYS ARE VARYING GREATLY AS THE FG COMES AND GOES.
CONDITIONS SHUD GRADUALLY IMPROVE ON WED AS A LOW PRESS SYSTEM OVR
IA MOVES TWRD NRN LWR MI. THIS WILL BRING PDS OF RA AND STRONGER
NW WINDS WHICH WILL GENERALLY IMPROVE VSBY AND BRING CIGS UP TO
MVFR.
&&
.POINT TEMPS/POPS...
DLH 38 24 34 20 / 40 20 10 10
INL 36 19 30 20 / 20 10 10 0
BRD 40 24 35 23 / 60 10 0 0
HYR 42 28 35 23 / 70 40 20 10
ASX 43 30 37 25 / 60 50 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THURSDAY FOR LSZ121-146>148.
&&
$$
CANNON/DAP
