Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 231539 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1039 AM CDT SAT AUG 23 2014

.UPDATE...
ISSUED AT 1038 AM CDT SAT AUG 23 2014

EXTENDED ISOLATED SHOWERS/DRIZZLE AROUND AND JUST NORTH OF THE
DULUTH AREA THIS MORNING AS RADAR CONTINUES TO INDICATE THIS BAND
OF VERY LIGHT PRECIP ADVANCING SLOWLY TO THE WEST. NO OTHER
SIGNIFICANT CHANGES WERE MADE TO THE FORECAST. STILL EXPECTING
CLOUDY SKIES TODAY WITH COOLER CONDITIONS AROUND THE PERIPHERY OF
LAKE SUPERIOR AND SHOWERS AND STORMS ENCROACHING FROM THE W AND SE
THIS EVENING. A FEW OF THESE STORMS COULD PRODUCE HEAVY RAIN
TONIGHT.

UPDATE ISSUED AT 703 AM CDT SAT AUG 23 2014

UPDATED AVIATION SECTION.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 326 AM CDT SAT AUG 23 2014

A COLD FRONT WAS LOCATED OVER THE WESTERN EDGE OF THE FA AT 07Z WITH
A LIGHT AND VARIABLE WIND AHEAD OF THE FRONT AND A NNE WIND BEHIND
THE FRONT. THE WEAK CONVERGENCE AHEAD OF THE FRONT HAS ALLOWED FOR A
FEW SHOWERS...BUT THEY HAVE DISSIPATED. AN ENE FLOW OVER LAKE
SUPERIOR IS ONCE AGAIN ANTICIPATED TODAY WITH FOG ADVECTING IN OFF
THE LAKE INTO THE TWIN PORTS AND ALONG THE PERIPHERY OF THE LAKE.
FOG ELSEWHERE IS DUE TO RADIATIONAL EFFECTS AND WILL BURN OFF BY
16Z. THE COLD FRONT SHOULD RETREAT A BIT WWD AND BE JUST ON THE EDGE
OF THE WESTERN FA BY 18Z. MEANWHILE...UPPER LEVEL RIDGING IS
BUILDING OVER THE WESTERN GREAT LAKES AND IS FORECAST TO BISECT THE
FA FROM THE ARROWHEAD TO NW WI. WITH THE WESTERN HALF OF THE FA ON
THE WEST SIDE OF THE RIDGE...PIECES OF SHORT WAVE ENERGY WILL RIDE
UP INTO THE DAKOTAS. THIS WILL RESULT THUNDERSTORM CHANCES IN THE
DAKOTAS AND NOT IN THE FA. THEREFORE...THE PCPN CHANCES ARE BEING
REMOVED UNTIL 23Z WHEN A POP IS INTRODUCED TO THE SW CORNER OF
SOUTHERN CASS COUNTY. EXPECT FOG TO PERSIST AROUND THE PERIPHERY OF
LS ALL DAY.

THE UPPER RIDGE MOVES E OF THE FA BY 06Z WHILE A SFC LOW GETS
ORGANIZED IN THE CENTRAL PLAINS AND LIFTS NWD INTO NW ND BY 12Z
SUNDAY. MEANWHILE...THE SFC FRONT MOVES N INTO CANADA PUTTING THE FA
IN A STRONG SOUTHERLY FLOW. SHORT WAVE ENERGY BEGINS TO RIDE UP INTO
THE FA AHEAD OF A CUT OFF UPPER LOW IN THE LEE OF THE ROCKIES IN
MONTANA. HAVE GRADUALLY RAMPED UP POPS SATURDAY NIGHT. BEFORE THE
THUNDERSTORMS ARRIVE TO THE NORTH SHORE...AN ONSHORE WIND AND
OROGRAPHIC LIFT WILL PRODUCE MORE FOG AND HAVE IT MENTIONED UNTIL
06Z SUNDAY.

THE CUT OFF UPPER LOW MEANDERS INTO NW ND BY 00Z MONDAY LEAVING THE
FA IN A STIFF SLY FLOW. PIECES OF SHORT WAVE ENERGY WILL MOVE NEWD
THROUGH THE FA AND BRING CONTINUED CHANCES OF THUNDERSTORMS. IF THE
SUN CAN FINALLY BREAK THROUGH ON SUNDAY...MAX TEMPS WILL WARM INTO
THE MIDDLE 80S OVER THE SOUTHERN TIER OF ZONES. INSTABILITY
INCREASES THROUGH THE DAY ON SUNDAY AND THERMODYNAMIC PROFILES
SUGGEST THE POTENTIAL FOR SOME SEVERE STORMS BY LATE AFTERNOON. SEE
THE DAY 2 CONVECTIVE OUTLOOK FROM SPC FOR THE FINER DETAILS. EVEN
WITH PWATS TO NEAR 1.75 INCHES...STORM MOVEMENT WILL BE RELATIVELY
QUICK REDUCING THE POSSIBILITY OF FLASH FLOODING.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 326 AM CDT SAT AUG 23 2014

THE COLD FRONT WILL FINISH PUSHING THROUGH THE FORECAST AREA SUNDAY
EVENING...WITH SHOWERS AND THUNDERSTORMS CONTINUING TO FORM ALONG
IT.  TOO SOON TO DETERMINE HOW LATE IN THE EVENING THE SEVERE THREAT
CONTINUES...BUT DEPENDS ON HOW FAST THE LINE MOVES...HOW MUCH
INSTABILITY BUILT UP DURING THE DAY...AND OUR EVENTUAL SHEAR
PARAMETERS.  IT COULD BE AN INTERESTING NIGHT.  HAVE KEPT HIGH POPS
IN THE EVENING...AND THEN ALLOWED A DIMINISHING TREND OVERNIGHT.
TEMPERATURES TO REMAIN MILD OVER THE EAST...BUT OVER THE WEST WE
COULD GET INTO THE MID 50S AS THE COOLER AND DRIER AIR MOVES IN.

THE STRONG SURFACE LOW WILL BE NORTH OF THE AREA BY MONDAY
MORNING...AND MOVE OFF TO THE NORTHEAST MONDAY NIGHT AND TUESDAY.
THIS WILL LEAVE THE FORECAST AREA IN BETWEEN SYSTEMS...WITH
NORTHWEST FLOW LEFT BEHIND THE DEPARTING SYSTEM AND A SURFACE RIDGE
BUILDING INTO THE AREA.  THUS...HAVE DRY OR VERY SMALL POPS FOR
MONDAY AND MONDAY NIGHT.  THE MODELS HAVE BEEN HINTING AT A
SHORTWAVE THAT MOVES ACROSS THE MIDWEST TUESDAY AND WEDNESDAY...BUT
MAINLY AFFECTS AREA SOUTH OF THE FORECAST AREA...THOUGH SOME MODELS
BRUSH THE SOUTHERN CWA WITH RAIN.  HAVE DECIDED TO CARRY SOME POPS
ACROSS THE SOUTH FOR BOTH DAYS FOR NOW AS CANNOT DISCOUNT THE WETTER
SOLUTION.  MONDAY HIGHS WILL BE COOLER THAN SUNDAY...AND COOL
FURTHER INTO THE MID 60S TO MID 70S FOR TUESDAY AND WEDNESDAY.

A STRONG SURFACE RIDGE BUILDS INTO THE AREA FOR THURSDAY AND
FRIDAY...AND CAN WITH FAIRLY HIGH CONFIDENCE PUT A DRY FORECAST OUT
THERE FOR BOTH DAYS.  TEMPERATURES REMAIN COOL WITH HIGHS IN THE 70S
BOTH DAYS...WARMING A LITTLE ON FRIDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 703 AM CDT SAT AUG 23 2014

WIDESPREAD IFR TO LIFR CIGS AND VISIBILITIES VARYING BETWEEN VFR
AND IFR IN LIGHT NORTHEAST FLOW THIS MORNING. A STRONG SURFACE LOW
OVER WESTERN NEBRASKA THIS MORNING WILL MOVE NORTH TODAY AND
TONIGHT. THIS WILL MAINTAIN THE EASTERLY FLOW ACROSS THE AREA
TODAY. CIGS ARE EXPECTED TO LIFT TO MVFR TO VFR GENERALLY BETWEEN
15Z AND 18Z. AFTER 00Z CIGS TO LOWER AGAIN TO WIDESPREAD IFR TO
LIFR...WITH VISIBILITIES AGAIN VARYING BETWEEN IFR AND VFR.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  67  63  80  61 /  20  60  60  70
INL  77  63  79  55 /  10  80  70  50
BRD  76  67  84  56 /  10  70  70  40
HYR  79  69  85  65 /  10  20  40  60
ASX  71  64  85  66 /  10  20  70  60

&&

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

$$

UPDATE...BJT
SHORT TERM...GSF
LONG TERM...LE
AVIATION...LE





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