Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 300527
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1227 AM CDT TUE SEP 30 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 333 PM CDT MON SEP 29 2014

CLOUDS...WINDS AND TEMPERATURES THE MAIN CONCERN THE NEXT 24 HOURS
AS A SURFACE RIDGE SAGS SOUTH OVER THE GREAT LAKES AND A SURFACE LOW
DEVELOPS OVER THE WESTERN PLAINS.  CLOUDS HAVE BEEN SURPRISINGLY
PERSISTENT OVER THE FORECAST AREA THIS AFTERNOON EVEN WITH THE RIDGE
BUILDING IN AND THE SLIGHTLY DRIER DEWPOINTS MOVING IN FROM THE
NORTH.  HOWEVER...THIS HAS NOT BEEN ENOUGH TO COUNTERACT THE
CONVERGENCE AND TERRAIN EFFECTS OF THE NORTHEAST WIND MOVING OVER
OUR RIDGE ALONG THE NORTH SHORE OF LAKE SUPERIOR...AND THERE HAS
BEEN VERY PERSISTENT CLOUD COVER AND EVEN DRIZZLE THERE.  IN
FACT...EXPECT THAT THIS CLOUD COVER WILL BE PERSISTENT ALL NIGHT AND
INTO TUESDAY MORNING.  ELSEWHERE THOUGH...THE DRIER AIR MOVING IN
SHOULD WORK ITS MAGIC AND SOME CLEARING CAN BE EXPECTED DURING THE
EVENING HOURS.  THUS...MIN TEMPS TONIGHT TO BE A CHALLENGE AND HAVE
GONE WITH UPPER 30S AND LOW 40S WHERE THE CLOUD COVER TO BE THE MOST
PERSISTENT...AND MID TO UPPER 30S ELSEWHERE.  TUESDAY THE SURFACE
RIDGE TO SHIFT FARTHER EAST AND THE LOW OVER THE PLAINS TO BEGIN TO
MOVE NORTHEAST INTO SOUTH DAKOTA...INCREASING OUR LOW LEVEL
SOUTHEAST FLOW AND BRINGING SOME WARMER TEMPS INTO THE AREA.  ONCE
AGAIN...THE STRATUS WILL LINGER OVER THE NORTH SHORE OF LAKE
SUPERIOR FOR AT LEAST THE MORNING...BUT EXPECT THAT AT LEAST SOME OF
IT WILL MIX OUT AS THE WARMER AIR MOVES IN.  HIGHS TO RANGE FROM THE
50S NEAR LAKE SUPERIOR AND EVEN SOMEWHAT INLAND OF THE NORTH
SHORE...AND UPPER 50S AND LOW 60S ELSEWHERE.  THE SURFACE LOW TO
PUSH SHOWERS TOWARDS THE AREA IN THE AFTERNOON...BUT EXPECT THIS TO
HOLD OFF UNTIL THE EVENING FOR NEARLY THE WHOLE AREA.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 321 PM CDT MON SEP 29 2014

THE UPPER AIR PATTERN THIS PERIOD WILL BE ACTIVE WITH A SERIES OF
MIGRATORY SHORTWAVE TROFS EMBEDDED WITHIN A BROAD TROF COVERING THE
NRN ROCKIES AND NRN PLAINS. THE INITIAL SYSTEM EJECTS NORTH OF THE
REGION TUES NIGHT AS BLOCKING MID LVL RIDGE HOLDS IN PLACE OVER THE
OHIO VALLEY. CONVECTIVE OPPORTUNITY IS RATHER LIMITED BASED ON FCST
SHEAR/INSTABILITY WITH SREF CPTP SHOWING LOW PROB OF THUNDER IN SRN
EDGE OF CWA. QPF AMOUNTS MAY AVERAGE BETWEEN A QUARTER TO ONE HALF
INCH OVER ERN THIRD OF CWA...ESPECIALLY IN WISC ZONES AS FRONT SLOWS
FORWARD SPEED. THE INITIAL COLD FRONT WILL WEAKEN/DISSIPATE OVER THE
REGION BY WED NIGHT AS NEXT AMPLIFYING SHORTWAVE MOVES INTO NRN
ROCKIES. SUPERBLEND GIVES POPS THROUGHOUT THE WEEK BUT THE MASS
FIELDS SUGGEST A BRIEF DRY SPELL MAY OCCUR THURSDAY BEFORE MUCH
STRONGER FRONTL BDRY ARRIVES THUR NIGHT.STRONG KINEMATICS FCST WITH
SECOND WEATHER SYSTEM SO IMPACTS WILL PROBABLY OCCUR OVER LAKE
SUPERIOR AND MOMENTUM TRANSFER OVER LAND TO PROVIDE SIGNIFICANT
GUSTS. ECMWF IS MOST AGGRESSIVE IN STRENGTHENING A CLOSED MID LVL
LOW OVERHEAD FRIDAY WITH GFS/GEM FAVORING HIGHER MAGNITUDE OF MID
LVL TROF OVER SRN CANADA. BRISK NW MID LVL FLOW THROUGH WEEKEND MAY
PRESENT A CHALLENGE FOR TIMING ANY PERIODS OF PRECIP WITH INITIAL
GUESSTIMATE SUNDAY FOR NEXT ROUND OF SHOWERS. TEMPS MAY BRIEFLY
TREND ABOVE CLIMO THURSDAY BETWEEN SYSTEMS OTHERWISE BLO CLIMO MAX
TEMPS EXPECTED THIS PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE SEP 30 2014

A LARGE AREA OF LOW CLOUDS WITH A MIX OF MVFR AND IFR CEILINGS WILL
ENCOMPASS THE FORECAST AREA THROUGH DAY BREAK. THERE REMAINS
DIFFICULTY IN DETERMINING TIMING OF LIFTING CEILINGS TUESDAY...DUE
TO THE INFLUENCE OF A STRONG SUBSIDENCE INVERSION. HAVE KEPT MVFR
CONDITIONS AT KHIB AND KDLH THROUGH THE TAF PERIOD. INTRODUCED A
TREND TO VFR WITH SCATTERED SKIES AT KBRD...KINL AND KHYR DURING THE
LATE AFTERNOON...WITH A RETURN TO MVFR CIGS THROUGH THE EVENING.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  44  59  50  63 /  40  40  30  30
INL  45  63  48  60 /  20  30  20  30
BRD  51  66  50  63 /  60  20  20  20
HYR  48  62  52  65 /  40  60  50  30
ASX  45  62  53  64 /  20  50  40  30

&&

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

$$

SHORT TERM...LE
LONG TERM...CANNON
AVIATION...MELDE






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