Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 290850
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
350 AM CDT FRI AUG 29 2014

.SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON)
ISSUED AT 349 AM CDT FRI AUG 29 2014

MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE
CURRENT RAIN SHOWERS TRACKING NEWD THROUGH NE MN THIS
MORNING...THE NEXT ROUND OF SHOWERS AND STORMS EXPECTED TO MOVE IN
FROM THE SOUTH IN THE NEXT 2 TO 3 HOURS AND SPREAD TO THE NE
THROUGH THE DAY. THE MAIN THREAT FROM THE STORMS WILL BE HEAVY
RAIN AND LIGHTNING...WITH THE HEAVIEST RAINFALL LIKELY OVER NW WI.
AREAL COVERAGE AND INTENSITY OF STORMS DECREASES THIS EVENING AS
THE SYSTEM EXITS TO THE EAST...BUT SLIGHT CHANCES FOR WEAK
CONVECTIVE SHOWERS AND STORMS REMAIN THROUGH SAT AFTERNOON.

UPPER WAVE CURRENTLY SITUATED OVER THE CENTRAL PLAINS WITH DECENT
WAA AND MOISTURE TRANSPORT FROM THE SOUTH OCCURRING AHEAD OF THE
SYSTEM ACROSS THE MID MS RIVER VALLEY INTO SRN MN. A SFC LOW
POSITIONED AROUND SIOUX FALLS WILL TRACK TO THE EAST AND COMBINE
WITH A COLD FRONT/SFC TROUGH MOVING IN ACROSS THE NRN PLAINS
TODAY. AN AREA OF MDT-HVY SHOWERS AND ISO STORMS HAS DEVELOPED
ACROSS SRN MN THIS MORNING...NORTH OF A SFC WARM FRONT DRAPED
OVER SRN IA. THIS AREA OF ELEVATED CONVECTION IS EXPECTED TO MOVE
NWD INTO OUR FORECAST AREA IN THE NEXT 3 HOURS OR SO AND EXPAND
NEWD THROUGH THE REGION. LARGE SCALE LIFT FROM THE INCOMING UPPER
TROUGH COMBINED WITH WAA...DEEP MOISTURE...AND INCREASING
ELEVATED INSTABILITY WILL ALL CONTRIBUTE TO AN EXPANSION OF
SHOWERS AND STORMS OVER THE AREA TODAY. THE MAIN CONCERNS WILL BE
HEAVY RAIN POSSIBLE ACROSS NW WI...AND LIGHTNING. COULD SEE AROUND
AN INCH OF RAINFALL FROM SIREN TO ASHLAND AND AREAS SOUTH AND
EAST. OTHER LOCATIONS EXPECTING TO RECEIVE AROUND A QUARTER TO
HALF INCH.

THE UPPER LOW AND ASSOCIATED SFC LOW WILL BE POSITIONED OVER NRN
WI LATE FRI NIGHT/EARLY SAT MORNING AND ALLOW SHOWERS TO LINGER
ACROSS THE ERN HALF OF THE NORTHLAND. HIGH PRESSURE BUILDS IN
QUICKLY FROM THE WEST ON SATURDAY...BUT NOT BEFORE AFTERNOON
CUMULUS CLOUDS DEVELOP AND BRING IN A SLIGHT CHANCE OF SHOWERS AND
WEAK STORMS IN THE AFTERNOON.

TEMPERATURES TODAY WILL BE SLIGHTLY COOL WITH HIGHS ONLY IN THE
60S AND LOWER 70S. STRONG PRESSURE FALLS ACROSS WRN LAKE SUPERIOR
FROM THE APPROACHING SFC TROUGH TO THE WEST WILL INDUCE A MODEST
LAKE BREEZE...WINDS AROUND 10 TO 15 MPH...AND KEEP TEMPS ADJACENT
TO LS A TAD COOLER. LOWS TONIGHT WILL ONLY DROP INTO THE 50S AND
LOWER 60S DUE TO AN ABUNDANT AMT OF CLOUD COVER. TEMPS WILL BE
SLIGHTLY WARMER ON SAT WITH HIGHS IN THE LOWER TO MID 70S...EXCEPT
AROUND LAKE SUPERIOR WHERE ANOTHER LAKE WIND WILL KEEP HIGHS ONLY
IN THE 60S.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 349 AM CDT FRI AUG 29 2014

THE EXTENDED PERIOD WILL FEATURE PERIODIC CHANCES FOR SHOWERS AND
STORMS WITH THE BEST CHANCE OCCURRING WITH A SYSTEM SUNDAY INTO
MONDAY MORNING. CONFIDENCE IS LOWER TONIGHT THAN YESTERDAY WITH A
LATE PERIOD SYSTEM.

SATURDAY NIGHT SHOULD BE DRY FOR MOST AREAS AS A WEAK SHORTWAVE
RIDGE MOVES THROUGH. THE GFS AND ECMWF REMAIN IN OK AGREEMENT
REGARDING A SHORTWAVE/FRONTAL BOUNDARY THAT WILL IMPACT THE
NORTHLAND SUNDAY INTO MONDAY BUT THE NAM IS QUITE A BIT SLOWER. WE
FOLLOWED CLOSER TO THE GFS/ECMWF. A MOIST AIRMASS WILL ADVECT INTO
THE REGION SATURDAY NIGHT...CONTINUING INTO SUNDAY WITH PWAT VALUES
RISING TO 1.6 TO 1.85 PER THE GFS/NAM. SHOWERS/STORMS WILL DEVELOP
AND BECOME LIKELY DURING THE DAY SUNDAY OVER WESTERN AREAS...THEN A
WIDESPREAD AREA OF PRECIP WILL MOVE EAST SUNDAY NIGHT AND THEN
DIMINISH FROM WEST TO EAST MONDAY. THERE WILL BE A HEAVY RAIN THREAT
WITH SUCH A MOIST AIRMASS IN PLACE AND STRONG FORCING. IF PWAT
VALUES RISE TO 1.75 INCHES...IT WILL BE NEAR 3SD ABOVE NORMAL FOR
THIS TIME OF YEAR. THERE WILL ALSO BE A THREAT FOR SEVERE
STORMS...ESPECIALLY LATER SUNDAY AFTERNOON INTO THE EVENING HOURS.
DEEP LAYER SHEAR IS FORECAST TO BE FROM 30-40 KNOTS AND AMPLE
INSTABILITY. THE THREAT FOR SHOWERS/STORMS WILL DIMINISH FROM WEST
TO EAST MONDAY.

THE UPPER FLOW WILL TRANSITION TO ZONAL WITH SEVERAL CHANCES FOR
SHOWERS/STORMS THROUGH THE REST OF THE PERIOD. NO REAL ORGANIZED
SIGNIFICANT SYSTEMS LOOK TO OCCUR THROUGH THE REST OF THE EXTENDED.
THE MODELS YESTERDAY WERE IN DECENT AGREEMENT DEVELOPING A
STATIONARY FRONT JUST SOUTH OF THE NORTHLAND. THE 00Z MODELS ARE NOT
IN AS GOOD AGREEMENT AND ARE MORE PROGRESSIVE LATE IN THE PERIOD.

HIGHS FOR MOST AREAS THROUGH THE PERIOD ARE EXPECTED TO BE IN THE
SEVENTIES...WITH SUNDAY THE WARMEST DAY FOR MOST AREAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1228 AM CDT FRI AUG 29 2014

MOISTURE SURGING NORTHWARD THROUGH THE UPPER MIDWEST WILL SET THE
STAGE FOR NUMEROUS SHOWERS AND THUNDERSTORMS THROUGHOUT THE TAF
PERIOD. MAINLY VFR CONDITIONS OVER NORTHERN AREAS WILL GIVE WAY TO
GRADUALLY LOWER CIGS/VSBYS...INCLUDING SOME MVFR AND IFR
CIGS/VSBYS. THESE CONDITIONS WILL LARGELY PERSIST THROUGH THE
PERIOD FOR ALL LOCATIONS ONCE THEY SPREAD IN FROM THE SOUTH.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  66  57  69  55 /  80  30  20  10
INL  72  53  73  52 /  50  20   0  10
BRD  73  60  74  59 /  60  30  10  20
HYR  71  59  72  57 /  80  70  20  10
ASX  72  56  69  54 /  80  70  20  10

&&

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

$$

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





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