Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 221150
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
650 AM CDT FRI AUG 22 2014

.UPDATE...
ISSUED AT 650 AM CDT FRI AUG 22 2014

UPDATED AVIATION SECTION BELOW.

&&

.SYNOPSIS...
ISSUED AT 308 AM CDT FRI AUG 22 2014

MID LVL RIDGING CONTINUES OVER THE CWA EARLY THIS MORNING AS A
BROAD AREA OF WEAK LOW PRESSURE SHIFTS SLOW EAST UNDERNEATH.
LATEST RUC SHOWS A 925 LOW OVER WCTRL WISC WITH AN INVERTED SHEAR
AXIS EXTENDING NORTHWEST TOWARDS KBJI AND KROX. THIS IS FOLLOWED
BY A COLD FRONT STRETCHING FROM ERN MANITOBA SOUTH TO CENTRAL
SODAK. MAIN STORY OVER CWA THIS MORNING IS TRAPPED MOIST LAYER...
ABOUT 5K FT IN DEPTH...UNDERNEATH SUBSIDENCE INVERSION. BR/FG AND
EVEN SOME DRIZZLE IS OCCURRING IN MANY AREAS. A FEW CONVECTIVE
CELLS HAVE TRIED TO DEVELOP OVER SERN WISC ZONES IN AN AREA OF LOW
LVL THETAE RIDGE AXIS. LIMITED INSTABILITY HAS ALLOWED FAIRLY
SHORT TEMPORAL NATURE TO DEVELOPMENT.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014

TODAY...FCST MDL SNDGS SUGGEST IT MAY TAKE QUITE SOME TIME TO
DISSIPATE THE CANOPY OF STRATUS AND BR ACROSS THE REGION. COND
PRES DEFICITS SHOW A TREND TO DIMINISHING BR BY 14/15Z....THEN A
RELATIVELY SATURATED CLOUD LAYER FINALLY BREAKING AFTER 2PM.
PRECIP CHC SEEMS QUITE LIMITED BY RIDGING ALOFT AND LACK OF LOW
LVL FOCUS FOR CONVERGENCE. THE GREATEST OPPORTUNITY MAY ARISE IN
THE AFTERNOON AHEAD OF APPROACHING FRONTAL BDRY PUSHING TOWARDS
NWRN CWA. MID LVL WARMTH WILL LIMIT MUCH DEVELOPMENT UNTIL
AFTERNOON AS 70H THERMAL COOLING COMMENCES OVER WRN CWA.

TONIGHT...MID LVL RIDGE AMPLIFIES OVERHEAD TONIGHT IN RESPONSE TO
UPSTREAM STRENGTHENING OF TROF OVER ROCKIES. FRONTAL BDRY WILL
STALL NORTH AND WEST OF CWA HOWEVER ITS ASSOCIATED PREFRONTAL
THETAE RIDGE WILL BE NEARBY. ALTHOUGH THE DRY FORECAST WAS CARRIED
OVER FROM PREVIOUS FCSTR...WILL NEED TO WATCH FOR SOME DEVELOPMENT
OF CONVECTION MAKING IT INTO NWRN CWA TONIGHT.

TOMORROW...HEIGHT FALLS MOVE INTO WRN HIGH PLAINS WITH SFC LOW
ORGANIZING OVER SODAK. A SWRLY MID LVL FLOW WILL BEGIN OVER THE
CWA AS THE RIDGE AXIS SHIFTS EAST. SFC HIGH PRESSURE WILL INCREASE
OVER LAKE SUPERIOR WITH DISTINCT ONSHORE COMPONENT TO BDRY LYR
WIND. TOUGH FCST FOR PRECIP AS MAIN FOCUS APPEARS TO BE SHAPING UP
OVER THE WRN CWA BY LATE IN THE DAY. CLOUDS/PRECIP FCST FOR NORTH
SHORE BASED ON A COMBINATION OF TERRAIN LIFT AND A GRADUAL
DEEPENING OF SYNOPTIC SCALE MOIST LAYER.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 308 AM CDT FRI AUG 22 2014

THE STRONG SURFACE LOW WILL MOVE NORTH ALONG THE WESTERN MINNESOTA
BORDER SATURDAY NIGHT AND SUNDAY MORNING...BRINGING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS...MAINLY THE THE WESTERN PORTIONS OF THE
FORECAST AREA OVERNIGHT.  HAVE GONE AHEAD AN INCREASED POPS TO
CATEGORICAL THERE...WITH HIGH END CHANCE TO LIKELY POPS ELSEWHERE AS
THE WARM FRONT MOVES NORTH ACROSS THE REGION.  MODELS ARE GETTING
CLOSE ENOUGH TOGETHER TO HAVE A FAIRLY HIGH CONFIDENCE...THOUGH THE
TRACK IS STILL SOMEWHAT PROBLEMATIC.  WITH THE SURFACE LOW MOVING
NORTHEAST OF THE REGION SUNDAY AND SUNDAY NIGHT....A COLD FRONT IS
DRAGGED THROUGH THE AREA.  DEPENDING ON THE MODEL...THE TIMING
DIFFERS...BUT EITHER WAY WE ARE LOOKING AT MORE CHANCE TO LIKELY
POPS.  THE ECMWF...WHICH IS FARTHER WEST THAN THE GFS IMPLIES WE MAY
HAVE SOME POTENTIAL FOR SEVERE STORMS...AS THE FRONT COMES THROUGH
LATER AND ALLOWS FOR HEATING DURING THE DAY TO BUILD INSTABILITY
AHEAD OF IT.  WILL HAVE TO WATCH THIS CAREFULLY IN THE NEXT FEW
DAYS.  HAVE GONE WITH SOME FAIRLY WARM HIGH TEMPS ON SUNDAY...BUT IF
THE ECMWF WORKS OUT...THESE WILL NEED TO BE RAISED.   THIS STORM
LINGERS OVER WESTERN ONTARIO FOR MONDAY BEFORE MOVING OFF TO THE
NORTHEAST MONDAY AFTERNOON AND NIGHT...KEEPING SOME CHANCE POPS
GOING OVER THE AREA BOTH PERIODS WITH COOLER TEMPERATURES.

OUR NEXT SIGNIFICANT STORM SYSTEM COMES BY ON TUESDAY THROUGH
WEDNESDAY.  MODELS ARE VARYING SIGNIFICANTLY BY THIS POINT...WITH
THE THE GFS BRINGING AN AREA OF MODERATE TO HEAVY RAIN ACROSS THE
FORECAST AREA...AND THE ECMWF KEEPING IT FARTHER SOUTH AND DRIER FOR
US.  FOR NOW HAVE GONE WITH A BLEND APPROACH WITH SOME CHANCE POPS
AND WE WILL HAVE TO REVISIT WITH LATER FORECASTS.  A STRONG SURFACE
RIDGE BUILDS INTO THE AREA FOR WEDNESDAY NIGHT AND
THURSDAY....BRINGING COOLER TEMPERATURES AND HOPEFULLY A BIT MORE
SUNSHINE TO THE REGION.  LOWS BY WEDNESDAY NIGHT AND THURSDAY NIGHT
MAY DIP INTO THE 40S AGAIN FOR PORTIONS OF THE AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 650 AM CDT FRI AUG 22 2014

WIDE RANGE OF CONDITIONS ACROSS THE TERMINALS THIS MORNING...WITH
LIFR FOR KDLH...KHYR AND KBRD WHERE NORTHEAST FLOW OFF LAKE
SUPERIOR HAS GENERATED STRATUS AND EVEN SOME LIFR VISIBILITIES IN
FOG. KHIB IS IFR WITH KINL AT VFR CIGS...THOUGH VFR VISIBILITIES
BOTH LOCATIONS. CIGS AND VISIBILITIES EXPECTED TO GRADUALLY
IMPROVE THROUGH 20Z TODAY...WITH MOST TERMINALS RETURNING TO AT
LEAST MVFR CIGS AND VFR VISIBILITIES. THIS EVENING CIGS AND
VISIBILITIES TO DETERIORATE AGAIN AFTER 02Z...LIKELY DROPPING TO
IFR/LIFR CIGS AND VISIBILITIES FOR SEVERAL HOURS OVERNIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  71  60  70  61 /  20  10  20  60
INL  76  56  76  58 /  30  10  30  70
BRD  79  61  75  64 /  10  10  50  70
HYR  80  61  78  64 /  20  10  40  60
ASX  71  59  73  62 /  20  10  20  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MNZ037.

WI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR WIZ001.

LS...NONE.
&&

$$

UPDATE...LE
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...LE
AVIATION...LE






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