Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 180456
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1156 PM CDT THU APR 17 2014

.UPDATE...
ISSUED AT 745 PM CDT THU APR 17 2014

REMOVED THE MENTION OF SNOW OVER THE TIP OF THE ARROWHEAD. MADE
SOME OTHER MINOR ADJUSTMENTS.

&&

.SYNOPSIS...
ISSUED AT 314 PM CDT THU APR 17 2014

SFC LOW OVER UPPER MICHIGAN AS OF MID AFTN WITH CYCLONIC AND
RELATIVELY MOIST CIRCULATION LEFT IN ITS WAKE. SNOW CONTINUES ACROSS
ERN ARROWHEAD BUT WILL LET WSW EXPIRE AT 21Z AS DGZ/OMEGA COUPLET
HAS SHIFTED INTO ONTARIO AND LOW LVL FLOW IS BACKING ENOUGH TO
REDUCE/ELIMINATE FETCH INTO ELEVATED TERRAIN. WIDESPREAD CLOUD
CANOPY OVER MOST OF CWA AS COLD CONVEYOR CLOUDS ARE QUICKLY REPLACED
BY INSTABILITY CUMULUS UNDER 85H THERMAL TROUGH. EXCEPTION IS OVER
SWRN CORNER OF CWA WHERE DEEP LAYER DRYING HAS NOT ALLOWED FOR MUCH
CLOUD DEVELOPMENT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 314 PM CDT THU APR 17 2014

TONIGHT...MAIN ISSUE OVERNIGHT IS DEVELOPMENT OF BR/FG AS SFC HIGH
MOVES INTO REGION. THE FCST COND PRESS DEFICITS NEAR THE SFC SUGGEST
THAT SATURATION WILL OCCUR AS NOCTURNAL COOLING OF BDRY LYR TAKES
PLACE. BUFKIT PROFILES SHOW FAVORABLE HYDROLAPSES AT MOST SITES
EXCEPT SWRN PART OF CWA. ADDED AREAS OF FOG TO ACCOMMODATE THIS
POTENTIAL.

TOMORROW...SFC HIGH WILL MOVE SOUTHEAST INTO ERN WISC BY LATE
FRIDAY. A RETURN FLOW OF AIR WILL DEVELOP IN THE BDRY LYR DURING THE
DAY. WILL MAINTAIN COOLER CONDITIONS BY THE LAKE AS SFC PRESS SIGNAL
INDICATES MESOSCALE NOSE OF PRESSURE INTO HEAD OF THE LAKE BY AFTN.
A MID LVL RIDGE DEVELOPS OVER THE CWA SO NO SIGNIFICANT DEEP LAYER
ASCENT EXPECTED. STILL CONCERNED THAT A STRAY SHOWER OR A FEW
SPRINKLES AMY OCCUR NEAR SWRN CORNER OF CWA IN THE AFTN HRS. VERY
WEAK ISENTROPIC ASCENT MAY BE JUST ENOUGH TO ALLOW A DROP TO SURVIVE
ITS DOWNWARD DESCENT INTO RELATIVELY DRY AIR IN THE LOWEST 2K FT.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT  314 PM CDT THU APR 17 2014

THE NEXT LOW PRESSURE AREA COMES IN QUICKLY LATE FRIDAY NIGHT WITH
THE RETURN OF STRONG WARM AIR ADVECTION BEHIND THE RETREATING HIGH.
IN RESPONSE...A STRONG BAROCLINIC ZONE WILL SET UP AROUND DULUTH OR
JUST NORTH. THIS WILL KEEP MOST OF PRECIP ASSOCIATED WITH THIS
SYSTEM ACROSS NORTHERN MN. AND THE PRECIP TYPES COULD MAKE FOR AN
INTERESTING SATURDAY. IT STARTS OFF COLD ENOUGH FOR SNOW...THEN AS
THE MID LEVEL WARM NOSE PUSHES INTO THE AREA IT COULD CHANGE OVER TO
FREEZING RAIN...THEN FINALLY ALL RAIN AS THE WARM AIR ENGULFS THE
AREA. THERE IS SOME VERY STRONG LIFT IN THE GOOD DENDRITIC ZONE
ASSOCIATED WITH THIS SYSTEM SO A FEW GOOD INCHES OF SNOW LIKELY
BEFORE THE CHANGE OVER. AND WILL BE KEEPING AN EYE ON THIS TOO AS
THE FREEZING RAIN IS CONCERNING AND MAY NEED AS ADVISORY.

SUNDAY THROUGH TUESDAY...FOR THE MOST PART...THIS PERIOD LOOKS MUCH
WARMER AND DRY AS HIGH PRESSURE MOVES INTO THE REGION. THERE COULD
BE SOME LIGHT RAIN ACROSS THE NORTHERN FORECAST AREA SUNDAY NIGHT
AND MONDAY AS THE GFS AND ECMWF INDICATE A WEAK LOW PRESSURE SYSTEM
AND WEAK COLD FRONT MOVING THROUGH THE REGION. TEMPERATURES WILL
LIKELY BE NEAR OR SLIGHTLY ABOVE NORMAL.

TUESDAY NIGHT AND WEDNESDAY...THIS COULD EB ANOTHER ACTIVE PERIOD
WITH RAIN AND THUNDERSTORMS. THE GFS AND ECMWF ARE IN FAIRLY GOOD
AGREEMENT THAT A LOW PRESSURE SYSTEM WILL BE ORGANIZING IN THE HIGH
PLAINS NEAR THE BORDER BETWEEN MONTANA AND SASKATCHEWAN TUESDAY
NIGHT. THE MODELS INDICATE THAT THE ASSOCIATED MID LEVEL WARM FRONT
WILL GRADUALLY LIFT NORTH AND EAST INTO THE NORTHERN PLAINS AND
UPPER MIDWEST TUESDAY NIGHT AND WEDNESDAY AND LINGER THROUGH THE
REST OF THE WEEK. THIS COULD BRING SHOWERS AND THUNDERSTORMS TO THE
NORTHLAND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1155 PM CDT THU APR 17 2014

VFR EXCEPT AT HYR WHERE SOME BR AND ISOLD LIFR WITH FZFG UNTIL
08Z. MID CLOUDS ARRIVING FROM MN SHOULD BRING A STOP TO THE
RADIATIONAL BR/FZFG. ADD A VCSH MENTION AT INL AT 03Z AHEAD OF
SYSTEM MOVING INTO THE DAKOTAS FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  22  39  27  46 /  10  10  50  70
INL  16  44  30  50 /  10   0  70  70
BRD  22  45  33  57 /   0  10  50  60
HYR  17  44  28  54 /  10  10  10  70
ASX  21  39  24  50 /  10  10  30  70

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&

$$

UPDATE...GSF
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...CLC
AVIATION...GSF






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