Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 280244 AAB
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
944 PM CDT WED AUG 27 2014

.UPDATE...
ISSUED AT 944 PM CDT WED AUG 27 2014

WITH HIGH PRESSURE CENTERED NEARLY OVERHEAD THIS EVENING AND
MOSTLY CLEAR SKIES..TEMPS HAVE FALLEN RATHER RAPIDLY IN MOST
AREAS..BUT ESPECIALLY UP NORTH WHERE READINGS ARE ALREADY NEAR 50
DEGREES AS OF 9 PM. THE CLOSING TO SATURATION AND FORMATION OF
AREAS OF FOG OVER THE NEXT FEW HOURS SHOULD PUT THE BRAKES ON THE
RAPID TEMP FALL..WITH A MORE SUBDUED GLIDE TO NEAR OUR CURRENT
FORECAST LOWS IN ORDER FOR THE REST OF THE NIGHT. WE HAVE MADE THE
STANDARD ADJUSTMENTS TO ADJUST THE VARIOUS GRID ELEMENTS TOWARD
CURRENT OBSERVATIONAL AND LATEST SHORT RANGE GUIDANCE TRENDS..BUT
OVERALL CHANGES WERE MINOR FOR THE REMAINDER OF THE NIGHT. THE TWO
MOST SIGNIFICANT CHANGES WERE TO EXPAND FOR COVERAGE
OVERNIGHT..AND ALSO TO DELAY THE ONSET TIMES FOR THE BEST CHANCES
OF PRECIP TOMORROW BY 3-6 HOURS..ALSO IN LINE WITH NEW CONSENSUS
MODEL GUIDANCE. UPDATES ARE ALREADY AVAILABLE.

&&

.SYNOPSIS...
ISSUED AT 323 PM CDT WED AUG 27 2014

SFC HIGH PRESSURE OVERS THE REGION THIS AFTERNOON UNDERNEATH A
PROGRESSIVE MID LVL RIDGE. EXTENSIVE AREA OF SCT/BKN CU DEVELOPED
WITH DIURNAL HEATING TODAY...ESPECIALLY OVER SWRN CWA WHERE A
925/850 MOISTURE AXIS REMAINS FROM PREVIOUS FRONTAL BDRY. EXPECT A
DISSIPATION OF THIS CLOUD FIELD ONCE DIURNAL WARMING DECREASES THIS
EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 323 PM CDT WED AUG 27 2014

TONIGHT...SFC HIGH WILL SHIFT TO ERN GREAT LAKES BY EARLY MORNING WITH
WEAK RETURN FLOW SETTING UP OVER DECOUPLED BDRY LYR. AREAS OF FOG
ARE EXPECTED AGAIN...THIS TIME OVER THE ERN CWA WHERE FCST SFC COND
PRESS DEFICITS.

TOMORROW...ACTIVE WX PATTERN ORGANIZES OVER THE CTRL PLAINS AS
SIGNIFICANT MID LVL TROF ADVECTS EAST INTO NEB/KS. A LLJ IMPINGING
ON A STRONG LOW LEVEL THERMAL BDRY WILL SETUP A LARGE AREA OF
CONVECTION SOUTH OF THE REGION. ALTHOUGH 85H MSTR TRANSPORT DOES
INCREASE OVER THE CWA...IT APPEARS THAT ANY PRECIP DEVELOPMENT WILL
BE SLOWER TO OCCUR THAN ORIGINALLY ANTICIPATED. LARGE ANTICYCLONIC
BDRY LYR FLOW COMBINED WITH ANTECEDENT DRIER AIR WILL MAINTAIN A
WEDGE OF RELATIVELY DRIER AIR OVER THE NORTHERN AND EASTERN CWA.
WILL KEEP THUNDER OUT OF FCST THROUGH THE PERIOD AS LIMITED
INSTABILITY FCST...WITH SUPPORT FROM SREF CLOUD PHYSICS THUNDER
PARAMETER.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 323 PM CDT WED AUG 27 2014

AFTER A COUPLE DRY DAYS...WE WILL ONCE AGAIN BE ENTERING A PATTERN
THAT IS MORE UNSETTLED AND WET. THERE ARE SOME PRETTY SERIOUS MODEL
DIFFERENCES WITH RESPECT TO THE SYSTEM MOVING IN FROM THE SOUTHWEST
THURSDAY NIGHT AND FRIDAY. SURFACE LOW PRESSURE IS EXPECTED TO MOVE
INTO MN THURSDAY NIGHT...WITH MOISTURE SPREADING NORTHWARD INTO THE
LAKE SUPERIOR REGION. THE ECMWF AND NAM GENERALLY KEEP THE BULK OF
THE PRECIPITATION OVER NORTHERN WISCONSIN WITH THE TWIN PORTS BEING
ON THE EDGE OF THE MAJORITY OF THE PRECIPITATION. THE GFS AND GEM
BRING A BIG BATCH OF PRECIPITATION FURTHER NORTH INTO THE BRAINERD
LAKES AND INTO THE MN ARROWHEAD. AT THIS POINT WE FEEL THE ECMWF AND
NAM SOLUTIONS MAKE THE MOST SENSE...AND HAVE TRENDED OUR FORECAST
FOR THURSDAY NIGHT AND FRIDAY IN THAT DIRECTION. THIS SYSTEM WILL
THEN TREND TO THE SOUTH AND EAST LATER FRIDAY AND FRIDAY
NIGHT...WHILE A WEAK FRONTAL BOUNDARY DROPS ACROSS NORTHERN MN
FRIDAY AND FRIDAY NIGHT. IN GENERAL WE ARE LOOKING AT LIGHTER QPF
SATURDAY AND SATURDAY NIGHT...ALTHOUGH THE CHANCES LOOK TO BE ENOUGH
TO MENTION A WARRANT OF A SLIGHT/CHANCE FOR MUCH OF THE CWA. A
FAIRLY MAJOR SYSTEM IS EXPECTED TO WRAP UP SUNDAY NIGHT INTO
MONDAY...AS A BROAD TROUGH DEVELOPS IN THE UPPER MIDWEST AND SOUTH
CENTRAL CANADA. A NORTH TO SOUTH FRONTAL BOUNDARY IS EXPECTED TO
DEVELOP ACROSS THE UPPER MIDWEST FROM SUNDAY NIGHT INTO MONDAY WITH
ABUNDANT MOISTURE EXPECTED TO REACH OUR AREA. THIS TROUGH WILL
CONTINUE TO AFFECT THE AREA THROUGH MIDWEEK...WITH A FEW WEAK
SYSTEMS BRINGING A CHANCE OF PRECIPITATION. OTHERWISE IT SHOULD BE A
BIT ON THE COOL SIDE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 714 PM CDT WED AUG 27 2014

WEAK SURFACE HIGH PRESSURE CENTERED JUST SOUTHWEST OF DULUTH WILL
CONTINUE TO SLOWLY DRIFT EASTWARD OVERNIGHT. WITH LOSS OF DAYTIME
HEATING..LINGERING CUMULUS CLOUDS SHOULD MOSTLY DISSIPATE WITHIN A
COUPLE HOURS OF THE BEGINNING OF THE TAF PERIOD. WINDS ARE
EXPECTED TO BE LIGHT/VARIABLE OVERNIGHT. PERIODS OF MVFR/IFR
VISIBILITY IS POSSIBLE OVERNIGHT AS FOG FORMS IN SOME
LOCALES..WITH THE MOST SIGNIFICANT IMPACTS AT THE
CLIMATOLOGICALLY FAVORED SITES OF KHIB/KHYR..AND ALSO KBRD.

HIGH PRESSURE WILL MOVE SUFFICIENTLY EASTWARD BY THURS MORNING TO
ALLOW 5-8KT WINDS TO DEVELOP FROM THE SE/S AT ALL TAF
SITES..ALONG WITH INCREASING CLOUDS AND A CHANCE OF
SHOWERS/TSTORMS SPREADING INTO KBRD/KHYR AREAS BY THE LAST 6 HOURS
OF THIS TAF VALID PERIOD. WITH INCREASING PRESSURE FALLS TO OUR
SOUTHWEST DURING THE DAY THURSDAY..A SURGE OF EAST-NORTHEAST WINDS
IS EXPECTED TO PUSH INTO KDLH EARLY TO MID AFTERNOON.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  51  69  57  70 /   0  30  40  20
INL  45  75  55  74 /   0  10  10  40
BRD  53  69  59  76 /  10  40  20  20
HYR  47  70  59  73 /   0  60  60  30
ASX  48  72  58  69 /   0  40  60  30

&&

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

$$

UPDATE...MILLER
SHORT TERM...CANNON
LONG TERM...DAP
AVIATION...MILLER






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