Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 271750
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1250 PM CDT WED AUG 27 2014

.UPDATE...
ISSUED AT 1242 PM CDT WED AUG 27 2014

UPDATED FOR NEW AVIATION FORECAST DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 317 AM CDT WED AUG 27 2014

MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE
LINGERING RAIN SHOWERS THIS MORNING...MAINLY OVER NW WI...AND THE
AREAS OF FOG EXPECTED TO EXPAND THROUGH THE NEXT COUPLE HOURS AND
EVENTUALLY DISSIPATE BY THE MID-MORNING. QUIET CONDITIONS EXPECTED
TODAY AND TONIGHT WITH MORE FOG POSSIBLE THURSDAY MORNING...AND
ANOTHER ROUND OF RAIN SHOWERS MOVING IN FROM THE SOUTH THROUGH THE
DAY.

UPPER LEVEL S/W MOVING EWD ACROSS THE UPPER MIDWEST/WRN GREAT
LAKES AREA THIS MORNING...UNDERCUTTING A SFC HIGH...AND PRODUCING
SCATTERED RAIN SHOWERS. THIS TROUGH WILL MOVE QUICKLY TO THE EAST
THIS MORNING...AND WITH HEIGHTS RISING ALOFT COMBINED WITH THE SFC
HIGH...EXPECT THE REST OF TODAY AND TONIGHT TO REMAIN QUIET. WINDS
WILL REMAIN LIGHT WITH SKIES PARTLY TO MOSTLY SUNNY. TEMPERATURES
TODAY WILL WARM INTO THE UPPER 60S ACROSS THE ARROWHEAD AND INTO
THE LOWER TO MID 70S ELSEWHERE.

HIGH PRESSURE OVER THE GREAT LAKES TONIGHT WILL CONTINUE TO
INFLUENCE THE NORTHLAND WITH SKIES MOSTLY CLEAR AND COOL
TEMPERATURES AGAIN CONTRIBUTING TO ANOTHER ROUND OF FOG. EXPECT
LOW TEMPERATURES TONIGHT TO FALL INTO THE 40S AND LOWER 50S.

ON THURSDAY...A LEAD S/W AND ASSOCIATED INVERTED SFC TROUGH WILL
MOVE NEWD FROM THE SRN PLAINS INTO THE UPPER MIDWEST. AHEAD OF
THIS SYSTEM WAA AND MODEST LARGE SCALE LIFT FROM 500MB PVA WILL
ALLOW RAIN SHOWERS TO MOVE IN ACROSS THE SRN COUNTIES. INSTABILITY
PARAMETERS DURING THE DAY THUR WILL BE VERY WEAK...SO JUST WENT
WITH RAIN SHOWERS. COULD SEE A QUARTER OF AN INCH AROUND HINCKLEY
BEFORE 00Z FRIDAY.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 317 AM CDT WED AUG 27 2014

FLOW OVER THE REGION WILL START OFF ZONAL...THEN AMPLIFY AS A DEEPER
TROUGH MOVES INTO THE REGION BY EARLY NEXT WEEK. THE EXTENDED PERIOD
WILL FEATURE CHANCES FOR SHOWERS/STORMS FOR MOST PERIODS. SEVERAL
DIFFERENT FEATURES WILL IMPACT THE REGION. A SIGNIFICANT AMOUNT OF
MODEL UNCERTAINTY WILL ALSO BE PARTIALLY RESPONSIBLE FOR THE
EXTENDED PERIOD OF POPS.

MODEL DIFFERENCES SHOW UP IN THE FIRST PERIOD OF THE EXTENDED WITH
THE NAM AND ECMWF MORE BULLISH ON PRECIP CHANCES THURSDAY NIGHT
COMPARED WITH THE GFS. THE NAM IS MUCH FURTHER NORTH THAN EVEN THE
ECMWF. THE 00Z ECMWF HAS MADE A NORTHWARD PUSH WITH ITS LOW AND
PRECIP AREA CLOSER TO THE NAM COMPARED TO 12Z. WE ARE NOT READY TO
GO FULLY WITH THE NAM...BUT WILL PUSH POPS A BIT FURTHER NORTH WITH
THIS FORECAST. NORTHWEST WISCONSIN WILL SEE THE HIGHEST CHANCE FOR
PRECIP WITH THIS INITIAL SYSTEM. CHANCES FOR PRECIP WILL LINGER INTO
FRIDAY. WE HAVE A CHANCE AS WELL OVER FAR NORTHERN ZONES FRIDAY AS A
SEPARATE TROUGH IMPACTS THAT AREA.

THE NEXT SIGNIFICANT SYSTEM WILL MOVE IN SUNDAY NIGHT AND DEPART
LATER MONDAY/MONDAY EVENING. PWAT VALUES ARE FORECAST TO RISE A BIT
OVER 1.5 INCHES AND THE FORCING SHOULD BE STRONG WITH A STRONGER
UPPER WAVE AND A DECENT LLJ FORMING.  WE FEEL CONFIDENT ENOUGH TO
HAVE LIKELY POPS OVER THE WESTERN HALF SUNDAY NIGHT. THERE COULD BE
SOME TIMING CHANGES WITH THIS SYSTEM...BUT IT IS LOOKING MORE LIKELY
THAT A PERIOD OF MORE SIGNIFICANT RAINFALL WILL OCCUR BETWEEN SUNDAY
NIGHT AND MONDAY NIGHT. AT THIS TIME...HEAVY RAIN LOOKS TO BE MORE
OF A THREAT THAN SEVERE STORMS.

HIGH TEMPERATURES SHOULD REMAIN WITHIN A COUPLE DEGREES OF NORMAL
THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1242 PM CDT WED AUG 27 2014

A WIDESPREAD CU FIELD HAD DEVELOPED AS OF MIDDAY AND IT WILL
CONTINUE TO BE AN ISSUE THROUGHOUT THE AFTERNOON AND INTO EARLY
EVENING. FOR A SHORT TIME...WE WILL SEE SOME LOCAL MVFR CIGS BUT
WITH DAYTIME HEATING WE SHOULD SEE CLOUD BASES RISE TO VFR. SOME
LOCAL FOG WILL THEN DEVELOP OVERNIGHT...WITH SOME LOCAL IFR
CIGS/VSBYS. CONDITIONS WILL THEN IMPROVE ON THURSDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  70  51  69  56 /   0   0  10  40
INL  70  45  75  53 /   0   0  10  10
BRD  73  53  69  57 /   0  10  30  20
HYR  72  47  70  57 /  10   0  40  60
ASX  70  48  72  57 /  10   0  10  40

&&

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

$$

UPDATE...DAP
SHORT TERM...BJT
LONG TERM...MELDE
AVIATION...DAP






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