Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 272032
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
332 PM CDT THU AUG 27 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 332 PM CDT THU AUG 27 2015

HIGH PRESSURE OVER THE GREAT LAKES REGION WILL SHIFT EAST THROUGH
TOMORROW...LEAVING THE NORTHLAND IN LIGHT SOUTHERLY FLOW. THERE
WILL BE INCREASING CLOUD OVER THE SOUTHERN FORECAST AREA INTO
TONIGHT DUE TO A SYSTEM IN THE PLAINS. AN AREA OF LOW PRESSURE
NEAR THE NEBRASKA AND KANSAS BORDER IS EXPECTED TO LIFT TO THE ENE
THROUGH TONIGHT AND FRIDAY...PASSING THROUGH NORTHERN IOWA OR FAR
SOUTHERN MINNESOTA. MOST OF THE MODELS CONTINUE TO INDICATE THE
ASSOCIATED PCPN WILL PRIMARILY REMAIN SOUTH OF THE NORTHLAND...BUT
SOME OF THE NORTHERN FRINGES OF ITS RAIN COULD REACH NW WISCONSIN
LATE TONIGHT AND FRIDAY. EARLIER FORECASTS HAD THUNDER...BUT
REMOVED THIS CONSIDERING THE NAM/SREF/GFS/RAP INDICATE NEARLY NO
MUCAPE AS FAR NORTH AS THE SOUTHERN FORECAST AREA.

THERE IS THE POTENTIAL FOR FOG LATE TONIGHT AND EARLY FRIDAY.
MODEL SURFACE CONDENSATION PRESSURE DEFICITS SUGGEST A LOW THREAT
OF THIS FOG...AND NOT VERY CONFIDENT CONSIDERING INCREASING CLOUD
COVER AND THE EXPECTED SOUTHERLY FLOW AROUND 2 TO 3 MPH COULD HELP
PREVENT FOG FORMATION. THE PREVIOUS FORECAST HAD FOG...AND SINCE
IT CANNOT BE RULED OUT...KEPT PATCHY FOG FOR MOST OF THE
NORTHLAND. THE BEST CHANCES FOR FOG ARE LIKELY ACROSS THE NORTHERN
FORECAST AREA SINCE SKIES SHOULD BE CLEARER. OVERNIGHT LOWS WILL
LIKELY RANGE FROM THE UPPER 40S AND LOW 50S OVER THE NORTH...TO
THE MIDDLE TO UPPER 50S ELSEWHERE.

THE SOUTHERN FORECAST AREA MIGHT BE A LITTLE COOLER FRIDAY
BECAUSE OF THE CLOUD COVER AND SHOWERS ASSOCIATED WITH THE LOW
PASSING THROUGH THE UPPER MIDWEST. HOWEVER...THE NORTHERN FORECAST
AREA WILL BE WARMER. A LOW IN SOUTHERN CANADA WILL MOVE INTO NE
NORTH DAKOTA LATER IN THE AFTERNOON...AND ITS WARM FRONT WILL SET
UP SOMEWHERE NEAR THE NORTHERN FORECAST AREA. THE MODELS CONTINUE
TO INDICATE SHOWERS AND STORMS COULD DEVELOP NEAR AND NORTH OF THE
WARM FRONT LATE IN THE AFTERNOON OR EARLY EVENING WHEN AND IF THE
CAP BREAKS. A WEAK SHORTWAVE MIGHT MOVE THROUGH THE AREA AND HELP
DEVELOP THE STORMS. THE SREF/NAM/GEM/GEMREG MODELS SEEMED A LITTLE
EXTENSIVE AND TOO FAR SOUTH WITH PCPN CONSIDERING THE PLACEMENT OF
THE WARM FRONT...SO LEANED MORE ON THE NCEPWRF/GFS/ECMWF. THE
MODELS AND SOUNDINGS INDICATE THERE COULD BE SUFFICIENT CAPE AND
WIND SHEAR TO SUPPORT MORE ORGANIZED STORMS. THE GFS AND NAM
SOUNDINGS SUGGEST THE POTENTIAL FOR LARGE HAIL DUE TO THE SOMEWHAT
INVERTED V SOUNDINGS...SO THE DRIER AIR IN THE LOW LEVELS WOULD
NOT LEAD TO MUCH MELTING OF ANY HAILSTONES.

HIGHS ON FRIDAY SHOULD RANGE FROM THE UPPER 60S AND LOW 70S
ACROSS THE FAR SOUTH...TO THE UPPER 70S ACROSS NORTHERN MINNESOTA.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 PM CDT THU AUG 27 2015

DEPARTING LOW TO THE SOUTH WILL KEEP A CHANCE OF RAIN OVER THE
SOUTHEAST PORTION OF MY WISCONSIN ZONES ENDING BEFORE SUNRISE
FRIDAY NIGHT. MEANWHILE NORTHERN STREAM DISTURBANCE BRINGS AN AREA
OF LIGHT RAIN NEAR THE INTERNATIONAL BORDER THROUGH SATURDAY AM.
TRENDED TOWARD CONSENSUS GUIDANCE ON POPS FOR THIS EVENT AND
LEANED ON A BLEND OF CONSENSUS AND WPC GUIDANCE FOR QPF. THIS
YIELDED RAIN TOTALS NEAR ONE-QUARTER INCH...WHICH SEEMS TO BE A
REASONABLE START. SOME AREAS WILL LIKELY SEE A LITTLE MORE WHILE
OTHERS A LITTLE LESS. RIDGING AT THE SURFACE AND ALOFT BUILDS
ACROSS THE AREA FOR SATURDAY AFTERNOON THROUGH SUNDAY NIGHT. TEMPS
WILL GRADUALLY TREND WARMER THROUGH SUNDAY...RUNNING AROUND 10
DEGREES ABOVE AVERAGE.

SURFACE RIDGING WILL SLIDE EAST LATE SUNDAY NIGHT AND MID-LEVEL
HEIGHT FALLS ARE EXPECTED IN RESPONSE TO A PASSING UPPER TROF
MOVING THROUGH THE CANADIAN ROCKIES. A WEAK FRONTAL BOUNDARY WILL
PROGRESS EASTWARD OUT OF THE DAKOTAS OVERNIGHT...LEADING TO AN
INCREASE IN CLOUD COVER AND A CHANCE OF SHOWERS OR THUNDERSTORMS.
MOST FAVORED AREA FOR RAINFALL SEEMS TO BE ALONG MY NORTHERN ZONES
THROUGH TUESDAY MORNING...WITH THE HIGHEST POPS GENERALLY NORTH OF
A WALKER/AITKIN/DULUTH LINE. TEMPERATURES WILL REMAIN SLIGHTLY
ABOVE NORMAL DURING THIS PERIOD AS WELL.

BY MIDWEEK THE MID-LEVEL RIDGE AXIS WILL BE SITUATED OVER THE
CENTRAL GREAT LAKES. SEVERAL WEAK SHORTWAVES WILL LIFT
NORTHEASTWARD THROUGH THE FLOW YIELDING ANOTHER CHANCE OF
THUNDERSTORMS LATE WEDNESDAY NIGHT. CONFIDENCE DURING THAT PERIOD
WAS NOT HIGH ENOUGH TO WARRANT CHANGES TO THE CONSENSUS GUIDANCE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1229 PM CDT THU AUG 27 2015

DEVELOPING SURFACE LOW OVER NEBRASKA WILL MOVE EASTWARD THIS
AFTERNOON THROUGH FRIDAY. MOISTURE FROM THIS SYSTEM WAS LIFTING
NORTHWARD INTO NE MN/NW WI. EXPECT SCATTERED TO BROKEN SKY COVER
OVER THE TERMINALS THIS AFTERNOON AND TONIGHT AS A RESULT. AM A
LITTLE ON THE FENCE REGARDING FOG POTENTIAL TONIGHT. DO EXPECT
SOME FOG IN THE AREA...BUT WHETHER IT AFFECTS THE TERMINALS AND
HOW LOW VSBYS MAY DROP IS STILL UNCERTAIN. HAVE HIGHEST CONFIDENCE
IN BCFG NEAR DLH/HIB/INL WITH MUCH LOWER CONFIDENCE AT BRD/HYR DUE
TO LOWER CIGS EXPECTED. EVEN SO...ONLY TOOK VSBYS DOWN INTO MVFR
RANGE. LATER UPDATES MAY LOWER VSBYS FARTHER AT THOSE SITES.
PASSING UPPER WAVE MAY RESULT IN A FEW SHOWERS NORTH OF INL BEFORE
28.18Z...BUT FELT CHANCE WAS TO LOW THIS AFTERNOON TO WARRANT
VCSH.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  56  75  57  76 /  10  10   0   0
INL  53  79  60  80 /   0  40  40  10
BRD  60  76  56  80 /  10   0   0   0
HYR  58  72  55  77 /  20  20  10   0
ASX  57  75  55  74 /  10  10  10   0

&&

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

$$

SHORT TERM...GROCHOCINSKI
LONG TERM...HUYCK
AVIATION...GROCHOCINSKI/HUYCK


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