Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 200822
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
322 AM CDT MON OCT 20 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 322 AM CDT MON OCT 20 2014

THE MAIN SHORT TERM FORECAST ISSUE REVOLVES AROUND CLOUD COVER
THROUGH THE PERIOD...AND ITS AFFECT ON TEMPERATURES.

NORTHERLY FLOW ALOFT IS IN PLACE ACROSS THE REGION THIS MORNING AS
A TROUGH SWINGS EAST. A STRENGTHENING SUBSIDENCE INVERSION WILL
OCCUR TODAY AS SURFACE HIGH PRESSURE MOVES IN. A STRATUS DECK
WITH BASES FROM 1200-3500FT WAS OCCURRING FROM MANITOBA SOUTHEAST
THROUGH THE ARROWHEAD INTO THE UPPER PENINSULA. MOST OF THE MODELS
SHOW THIS CLOUD EXPANDING SOUTH TODAY AND THE STRONGER INVERSION
WILL MAKE IT TOUGH TO SCOUR OUT THE CLOUDS. THE MODELS DO SUGGEST THE
CLOUDS WILL GRADUALLY BREAK UP...MAINLY OVER WESTERN AREAS...AND
HOLD OVER THE EAST. WHERE EXACTLY THE LINE OF CLEARING SETS UP IS
STILL IN QUESTION. LOW LEVEL FLOW WILL BECOME MORE NORTHEASTERLY
THROUGH THE DAY INTO THE EVENING AND WILL MAKE IT TOUGHER FOR AREAS
AROUND LAKE SUPERIOR CLEAR OUT. WE DID INCREASE CLOUD COVER TODAY
FOR MOST AREAS...THEN DECREASED IT TONIGHT. THE EXCEPTION TONIGHT
WILL BE AROUND LAKE SUPERIOR WHERE A NORTHEAST/EAST FLOW WILL
OCCUR AND SHOULD ALLOW FOR MORE CLOUDINESS. IN ADDITION TO THE
CLOUD ISSUES...THERE WILL BE A TIGHT THERMAL GRADIENT ACROSS THE
NORTHLAND WITH 850MB TEMPS RANGING FROM AROUND +6C OVER OUR WESTERN
ZONES...TO -2C EAST. WE HAVE OUR WARMEST TEMPS IN THE BRAINERD
LAKES REGION AND COOLEST IN THE ARROWHEAD TODAY.

THE HIGH WILL MOVE EAST OF THE AREA TUESDAY ALLOWING FOR AN
INCREASING SOUTHEASTERLY FLOW. CLOUDS MAY HANG TOUGH FOR A TIME
AROUND LAKE SUPERIOR ON TUESDAY...BUT WE THINK THE INCREASING
SOUTHEAST FLOW OUT OF THE DRY HIGH WILL BE ENOUGH TO CAUSE THE
CLOUDS TO DIMINISH MOST AREAS TUESDAY. HIGHS WILL RANGE FROM THE
MID FIFTIES SOUTH AND WEST TO 45 TO 50 FROM THE TWIN PORTS INTO
THE ARROWHEAD.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 322 AM CDT MON OCT 20 2014

SURFACE HIGH PRESSURE WILL BE OVER THE CENTRAL GREAT LAKES REGION
TUESDAY EVENING. THERE WILL BE A PRONOUNCED MID/UPPER LEVEL RIDGE
OVER THE UPPER MIDWEST. SURFACE LOW PRESSURE WILL BE OVER THE
NORTHERN HIGH PLAINS...WHILE A POTENT SHORTWAVE WILL BE OVER THE
NORTHERN ROCKY MOUNTAIN STATES.

SOUTHERLY FLOW WILL INCREASE WEDNESDAY AS THE LOW PRESSURE TROUGH
MOVES INTO THE PLAINS. THE TROUGH WILL THEN MOVE THROUGH THE
NORTHLAND WEDNESDAY NIGHT AND THURSDAY. THIS LOW WILL BRING WARM AND
HUMID FLOW INTO THE UPPER MIDWEST. THERE WILL BE INCREASING PCPN
CHANCES FROM WEST TO EAST WEDNESDAY AND WEDNESDAY NIGHT. IT APPEARS
THIS SYSTEM WILL BRING WIDESPREAD RAINS OF ABOUT A TENTH TO QUARTER
INCH OF TOTAL RAINFALL TO THE NORTHLAND WEDNESDAY INTO THURSDAY. THE
PRECIPITABLE WATERS VALUES WILL BE OVER 1 INCH...WHICH IS PRETTY
SUBSTANTIAL FOR THIS TIME OF THE YEAR. THERE ARE SOME INDICATIONS
THAT THUNDERSTORMS ARE POSSIBLE. THE NAM12 AND GFS ARE SHOWING SOME
MODEST MOST UNSTABLE CAPE OVER THE WESTERN FORECAST AREA WEDNESDAY
AFTERNOON AND EVENING. AT THIS TIME...THINK IT IS TOO EARLY TO ADD
STORMS TO THE FORECAST GIVEN THE MARGINAL OF THE INDICATORS...BUT WE
MIGHT NEED TO ADD ISOLATED THUNDER TO SUBSEQUENT FORECASTS.

ANOTHER MID/UPPER LEVEL RIDGE WILL MOVE INTO THE CENTRAL UNITED
STATES FRIDAY. THIS WILL MAINTAIN THE WARM TEMPERATURES OVER THE
NORTHLAND. FRIDAY WILL LIKELY BE THE WARMEST DAY OF THE WEEK WITH
HIGHS REACHING THE LOW 60S...ABOUT 10 TO 15 DEGREES WARMER THAN
NORMAL. A COLD FRONT ASSOCIATED WITH A CANADIAN LOW PRESSURE SYSTEM
WILL MOVE THROUGH THE NORTHLAND FRIDAY NIGHT. THIS WILL BRING
SLIGHTLY COOLER WEATHER FOR SATURDAY...BUT WITH HIGHS STILL 5 TO 10
DEGREES ABOVE NORMAL.

BOTH THE GFS AND ECMWF ARE SHOWING LOW PRESSURE MOVING INTO THE
PLAINS DURING THE LATTER HALF OF THE WEEKEND AND WITH A WARM FRONT
LIFTING INTO THE NORTHLAND. THE ECMWF AND GFS ARE SUGGESTING THIS
SYSTEM COULD BRING SIGNIFICANT PCPN TO THE NORTHLAND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1223 AM CDT MON OCT 20 2014

INCREASING NORTHWESTERLY GRADIENT IN THE WAKE OF DEPARTING SURFACE
LOW HAS ALLOWED WINDS TO SHIFT TO THE NORTHWEST THIS EVENING...AND
ALSO ALLOWED STRATUS TO ADVECT/DEVELOP SOUTHWARD INTO ALL TAF SITES
EXCEPT FOR KBRD AS OF 05Z.  WHILE CEILINGS ARE STILL MVFR..WE EXPECT
THEM TO LOWER INTO MVFR CATEGORY OVERNIGHT.  MAIN UNCERTAINTY FOR
MONDAY IS THE EXTENT TO WHICH CLOUDS WILL BE ABLE TO MIX OUT.  WITH
LOW LEVEL FLOW ACQUIRING AN EASTERLY COMPONENT BY AFTERNOON..WE
SUSPECT THAT WHILE CEILINGS MAY RISE INTO VFR CATEGORY..BROKEN
CEILINGS MAY BE ABLE TO PERSIST AT KHIB/KDLH/KHYR THROUGH MOST OF
THE DAY.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  50  36  47  36 /   0  10  10   0
INL  48  32  55  37 /   0   0   0   0
BRD  58  36  57  38 /   0   0   0   0
HYR  53  31  52  33 /   0   0   0   0
ASX  52  36  50  33 /  10  10  10   0

&&

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

$$

SHORT TERM...MELDE
LONG TERM...GROCHOCINSKI
AVIATION...GROCHOCINSKI/MILLER






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