FXUS63 KDLH 011615
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1015 AM CST TUE DEC 1 2009
.UPDATE...MADE SOME ADJUSTMENTS TO POPS/WX TO LINE UP BETTER WITH
CURRENT TRENDS PER SATELLITE AND RADAR. MADE ROOM FOR MORE
SUNSHINE OVER THE SOUTHERN HALF OF THE FA WHERE THERE IS LESS
CLOUD COVER. WITH MORE SUN...ALSO RAISED MAX TEMPS OVER THE
SOUTHERN TIER OF THE FA. EXPECTED INCREASE IN ONSHORE WINDS ALONG
THE NORTH SHORE AND HAVE ISSUED A SCA. REST OF THE FORECAST IN
GOOD SHAPE.
&&
.PREV DISCUSSION... /ISSUED 540 AM CST TUE DEC 1 2009/
AVIATION...12Z TAF ISSUANCE...
VFR EARLY THIS MORNING AS CEILINGS REMAIN HIGH IN ABSENCE OF LOW
LEVEL SATURATION. MDL COND PRESS DEFICIT SUGGEST INL/HIB WILL HAVE
MVFR/IFR CATEGORIES DEVELOPING AS LO PRESS MOVES TOWARDS REGION.
DLH ON THE DIVIDING LINE BETWEEN VFR/MVFR AS MOST OF THE
PRECIPITATION SHOULD REMAIN NORTH UNTIL POSSIBLY LATE
AFTERNOON/EVENING. BRD/HYR SHOULD KEEP RELATIVELY DRY WITH BRISK
SW WINDS TODAY. EXPECT A LARGE AREA OF STRATUS CLOUDS WITH MVFR
BASES TO ADVECT SOUTH AND THEN EAST BEHIND LO PRESS OVERNIGHT.
PREV DISCUSSION... /ISSUED 345 AM CST TUE DEC 1 2009/
DISCUSSION...
THRU WED...
MODELS IN REASONABLY GOOD AGMT ON POSITION AND EVOLUTION OF SFC LOW
OVR NWRN ND ATTM. LOW WILL DIP DOWN ACRS CENT MN AS IT PROGRESSES
EWD...MOVG E OF LK SUP BY MIDDAY WED. SPEED OF SYSTEM AND LACK OF A
GOOD MSTR SOURCE WILL LIMIT ACCUMS...BUT STRENGTH OF ASSOC
DYNAMICS OUGHT TO BE SUFFICIENT FOR 3-5 INCHES N OF THE IRON
RANGE...WITH LOCAL AMTS PSBLY TO ARND 6 INCHES CLOSE TO THE CN
BORDER. AMTS WILL THEN TAPER OFF TO LESS THAN AN INCH IN SRN PARTS
OF THE CWA. WILL ISSUE WSW FOR N OF THE RANGE RUNNING FROM NOON TDA
TO NOON WED. FUTURE SHIFTS MAY BE ABLE TO CANCEL EARLY...BUT WITH UPR
LVL CYC FLOW ALOFT THRU THE PD...IT WILL PRBLY NOT STOP SNOWING
COMPLETELY. THE MAJOR ACCUMULATING SNOW HWVR WILL PRBLY FALL FROM
MID AFTN TDA THRU VERY EARLY WED MRNG. WINDS ON BACK SIDE OF THE LOW
WILL ALSO BE A FACTOR ON WED...CAUSING SOME BLOWING AND DRIFTING.
EXPECT LOWER HIGH TEMPS ON WED AS CAA BEGINS TO SET UP...CONTINUING
THRU THE REST OF THE WEEK.
WEDNESDAY NIGHT THRU SUNDAY...
MDT/STRONG MDL CONSENSUS THAT A LARGE AMPLITUDE MID LVL TROF WILL
DOMINATE THE REGIONAL WEATHER PATTERN THIS PERIOD. BY BEGINNING OF
PERIOD...SHOULD HAVE ESTABLISHED A SNOW PACK UPSTREAM OF CWA AND INTO
AT LEAST NRN THIRD OF AREA. 85H TEMPS WILL DROP BELOW NORMAL VALUES
FOR THE PERIOD SO SHOULD ACTUALLY SEE MIN/MAX TEMPS DROP BELOW NORMS
TO SOME DEGREE. CLOUDS/PASSING SNSH WILL MODIFY TEMPS AT NIGHT. MAIN
QPF THIS PERIOD WILL BE ASSOCIATED WITH LES ACROSS SNOWBELT. SOME
CONTRIBUTING FACTORS OF NOTE: LAKE INDUCED CAPE SHOULD REACH BETWEEN
500/750 J/KG INDICATING MODERATE LVLS OF INSTABILITY...LAKE INDUCED
EQL MAINTAINS 10/15K FT THROUGHOUT PERIOD WITH NO INVERSION ISSUES
TO RESTRICT GROWTH OF LAKE CLOUDS...AND AT LEAST A 24/36 HR PERIOD
OF OMEGA WITHIN THE FAVORED DENDRITIC GROWTH ZONE. AS USUAL...ANY
SIGNIFICANT DEVIATIONS IN LOW LVL TRAJECTORY OFF LAKE WILL AFFECT
THE INTENSITY/LOCATION OF BEST PLUMES. MDL SIGNALS HAVE BEEN
CONSISTENT THAT SIGNIFICANT ACCUMULATION IS BECOMING MORE LIKELY
GIVEN SYNOPTIC PATTERN...TIME OF YEAR WITH OPEN LAKE....AND
ANOMALOUS 85H TEMPS. OTHERWISE SHORTWAVES EMBEDDED WITHIN DEEP
CYCLONIC CIRCULATION SHOULD ACT UPON RELATIVELY MOIST COLUMN TO
GENERATE PERIODIC SNSH/FLURRIES IN MOST AREAS.
AVIATION...06Z TAF ISSUANCE...
CLOUDS WILL RAPIDLY INCREASE ACROSS THE NRN/CTRL CWA WITH SNOW
DEVELOPING AT INL/HIB TERMINALS BY MID MORNING. MAINLY MVFR EXPECTED
ALTHOUGH OCCASIONAL MDT SNOW MAY DROP VSBY TO IFR CATEGORY. DLH WILL
EXPERIENCE MAINLY MVFR CIGS WITH SOME LT SNOW.MAINLY VFR AT BRD/HYR
THROUGH PERIOD.
&&
.POINT TEMPS/POPS...
DLH 35 23 29 15 / 20 40 30 10
INL 31 18 25 10 / 100 70 40 20
BRD 42 24 29 14 / 20 20 30 10
HYR 41 26 30 18 / 10 20 20 30
ASX 38 28 30 20 / 20 40 40 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY 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 FROM 10 PM THIS EVENING TO 4 PM CST
WEDNESDAY FOR LSZ140>145.
&&
$$
GSF/DONOFRIO
