Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 221754
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1254 PM CDT FRI AUG 22 2014

.UPDATE...
ISSUED AT 1252 PM CDT FRI AUG 22 2014

UPDATED FOR NEW AVIATION FORECAST DISCUSSION BELOW.

UPDATE ISSUED AT 959 AM CDT FRI AUG 22 2014

ADDED PATCHY DRIZZLE TO THE FORECAST THROUGH THE DAY AND KEPT
FOG...LOCALLY DENSE MENTIONED THROUGH THE AFTERNOON AROUND THE
TWIN PORTS...ESPECIALLY ALONG THE HILLSIDE AREA. LAKE BREEZE OFF
LS WILL CONTINUE TODAY AND INTO THE WEEKEND WITH COOL
TEMPERATURES...LOW CLOUDS AND PATCHY FOG AND DZ. REST OF THE
FORECAST LOOKS ON TRACK AT THIS TIME.

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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1252 PM CDT FRI AUG 22 2014

A MOIST EASTERLY FLOW WILL CONTINUE THROUGHOUT THE TAF PERIOD.
WE SHOULD START THE DAY LARGELY IN THE IFR/LIFR RANGE NEAR LAKE
SUPERIOR...AND MVFR TO IFR AT INLAND LOCATIONS. SOME IMPROVEMENT
IS POSSIBLE DURING THE AFTERNOON BUT WE SHOULD SEE CONDITIONS GO
RIGHT BACK TO LOWER VALUES OVERNIGHT. WE ARE EXPECTED LARGE SCALE
IFR/LIFR AND EVEN SOME VLIFR NEAR LAKE SUPERIOR OVERNIGHT AND
LINGERING INTO SATURDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  68  60  70  61 /  30  10  20  60
INL  74  57  76  58 /  20  10  30  70
BRD  78  61  75  64 /  10  20  50  70
HYR  76  61  78  64 /  20  20  40  60
ASX  71  59  73  62 /  30  20  20  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR MNZ037.

WI...BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR WIZ001.

LS...NONE.
&&

$$

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






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