Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 120538
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1238 AM CDT FRI SEP 12 2014

.UPDATE...
HAVE CONTINUED SMALL POPS THROUGH THE EVENING AS RADAR IMAGERY
SHOWS ISOLATED SHOWERS...MIXED WITH SLEET...CONTINUE TO TRACK
SOUTHEAST OVER THE REGION. ALTHOUGH THE H50 TROUGH AXIS WILL
SLOWLY DROP INTO THE BORDERLAND THIS EVENING...AND SETTLE OVER
NORTHERN MN OVERNIGHT...THE LOSS OF DAYTIME HEATING SHOULD
DIMINISH THE SHOWER ACTIVITY AND CLOUD COVER OVER THE NEXT FEW
HOURS.

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU SEP 11 2014

COMBINATION OF LIMITED HEATING AND STEEP LAPSE RATES BELOW 10 KFT
THIS AFTERNOON CONTINUE TO SUPPORT ISOLATED TO SCATTERED LIGHT
RAIN AND SLEET SHOWERS ACROSS MUCH OF THE CWA. COVERAGE IS
EXPECTED TO DECREASE RAPIDLY AFTER ABOUT 6 PM WITH THE WANING OF
DAYTIME HEATING..BUT SCATTERED TO BROKEN STRATOCUMULUS SHOULD
REMAIN IN MANY AREAS WELL INTO TONIGHT BEFORE CLEARING.

WHILE THE TENDENCY SHOULD BE FOR LOW CLOUDS TO SLOWLY CLEAR LATER
TONIGHT..MID AND HIGH CLOUDS SHOULD BE THICKENING ACROSS THE SOUTH QUITE
RAPIDLY LATER TONIGHT..AND TIMING OF THESE TWO FACTORS MAKES TEMP
FORECASTS FOR TONIGHT SOMEWHAT TROUBLESOME DESPITE LIGHT WINDS AND
A CHILLY AIRMASS. OUR CONFIDENCE IN WIDESPREAD FROST REMAINS
HIGHEST ACROSS THE NORTHERN TWO THIRDS OF THE CWA WHERE THE
AIRMASS IS COLDEST AND CLOUDS SHOULD HAVE THE BEST CHANCE TO CLEAR
LATER TONIGHT..AND WE HAVE HOISTED A FROST ADVISORY FOR AREAS
ROUGHLY ALONG AND NORTH OF A LINE FROM LONGVILLE TO THE TWIN
PORTS. OUR CONFIDENCE IS LOWER ACROSS THE SOUTH..AND ESPECIALLY IN
NW WISCONSIN WHERE LOTS OF RESIDUAL BOUNDARY LAYER MOISTURE FROM
RECENT RAIN EXISTS..ALONG WITH THE EXPECTATION OF THICKENING
CLOUDS AFTER MIDNIGHT. WE OPTED NOT TO ISSUE THE ADVISORY FOR
THESE AREAS..BUT DID ISSUE A SPECIAL WEATHER STATEMENT FOR PATCHY
FROST.

S/W TROF CURRENTLY COMING ONTO THE HIGH PLAINS OF THE WRN DAKOTAS WILL
RAPIDLY MOVE ACROSS THE UPPER MIDWEST FRIDAY/FRIDAY EVENING.
FORCING WILL BE STRONG..BUT SO WILL RELATIVE STABILITY FIELDS..AND
THE VERTICAL MOTION RESPONSE IS EXPECTED TO BE SOMEWHAT WEAKER
THAN WHAT MAY TYPICALLY BE EXPECTED WITH SUCH STRONG FORCING.
NONETHELESS..WE HAVE CONTINUED THIS PACKAGE WITH BRINGING A 4-7
HOUR PERIOD OF POPS ACROSS MUCH OF NW WISCONSIN FRI AFTERNOON AND
EVENING WITH THE STRONGEST FORCING. HOWEVER..WE HAVE ADJUSTED
TIMING LATER BY 3-5 HOURS /IN LINE WITH NEWEST GUIDANCE/ AND KEPT
WITH VERY LIGHT QPF AMOUNTS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU SEP 11 2014

THE BEGINNING OF THE PERIOD WILL BE COOLER THAN NORMAL. A SURFACE
HIGH PRESSURE RIDGE WILL MOVE THROUGH THE NORTHLAND...RESULTING IN
CLEAR SKIES AND LIGHT WIND SATURDAY MORNING. LOW TEMPERATURES
SATURDAY SHOULD DIP DOWN TO AT LEAST THE UPPER 20S AND LOWER
30S...IF NOT LOWER. A FROST ADVISORY WILL LIKELY BE NEEDED FOR THIS
TIME.

TEMPERATURES WILL REBOUND TO THE UPPER 50S AND LOW 60S OVER THE
WEEKEND. A PASSING TROUGH OF LOW PRESSURE WILL BRING A CHANCE OF
LIGHT SHOWERS SATURDAY NIGHT AND SUNDAY.

HIGH PRESSURE WILL MOVE BACK INTO THE NORTHLAND MONDAY. THERE COULD
BE LIGHT CONVECTIVE SHOWERS IN THE ARROWHEAD DUE TO THE COOL NW FLOW.

AN UPPER LEVEL RIDGE IN THE WESTERN UNITED STATES COULD BEGIN TO
SHIFT INTO THE CENTRAL UNITED STATES DURING THE MIDDLE OF NEXT
WEEK...WHICH WILL LIKELY BRING A WARMING TREND. HIGH TEMPERATURES
MIGHT REBOUND TO THE LOW TO MIDDLE 60S BY WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU SEP 11 2014

COMBINATION OF LIMITED HEATING AND STEEP LAPSE RATES BELOW 10 KFT
THIS AFTERNOON CONTINUE TO SUPPORT ISOLATED TO SCATTERED LIGHT
RAIN AND SLEET SHOWERS ACROSS MUCH OF THE CWA. COVERAGE IS
EXPECTED TO DECREASE RAPIDLY AFTER ABOUT 6 PM WITH THE WANING OF
DAYTIME HEATING..BUT SCATTERED TO BROKEN STRATOCUMULUS SHOULD
REMAIN IN MANY AREAS WELL INTO TONIGHT BEFORE CLEARING.

WHILE THE TENDENCY SHOULD BE FOR LOW CLOUDS TO SLOWLY CLEAR LATER
TONIGHT..MID AND HIGH CLOUDS SHOULD BE THICKENING ACROSS THE SOUTH QUITE
RAPIDLY LATER TONIGHT..AND TIMING OF THESE TWO FACTORS MAKES TEMP
FORECASTS FOR TONIGHT SOMEWHAT TROUBLESOME DESPITE LIGHT WINDS AND
A CHILLY AIRMASS. OUR CONFIDENCE IN WIDESPREAD FROST REMAINS
HIGHEST ACROSS THE NORTHERN TWO THIRDS OF THE CWA WHERE THE
AIRMASS IS COLDEST AND CLOUDS SHOULD HAVE THE BEST CHANCE TO CLEAR
LATER TONIGHT..AND WE HAVE HOISTED A FROST ADVISORY FOR AREAS
ROUGHLY ALONG AND NORTH OF A LINE FROM LONGVILLE TO THE TWIN
PORTS. OUR CONFIDENCE IS LOWER ACROSS THE SOUTH..AND ESPECIALLY IN
NW WISCONSIN WHERE LOTS OF RESIDUAL BOUNDARY LAYER MOISTURE FROM
RECENT RAIN EXISTS..ALONG WITH THE EXPECTATION OF THICKENING
CLOUDS AFTER MIDNIGHT. WE OPTED NOT TO ISSUE THE ADVISORY FOR
THESE AREAS..BUT DID ISSUE A SPECIAL WEATHER STATEMENT FOR PATCHY
FROST.

S/W TROF CURRENTLY COMING ONTO THE HIGH PLAINS OF THE WRN DAKOTAS WILL
RAPIDLY MOVE ACROSS THE UPPER MIDWEST FRIDAY/FRIDAY EVENING.
FORCING WILL BE STRONG..BUT SO WILL RELATIVE STABILITY FIELDS..AND
THE VERTICAL MOTION RESPONSE IS EXPECTED TO BE SOMEWHAT WEAKER
THAN WHAT MAY TYPICALLY BE EXPECTED WITH SUCH STRONG FORCING.
NONETHELESS..WE HAVE CONTINUED THIS PACKAGE WITH BRINGING A 4-7
HOUR PERIOD OF POPS ACROSS MUCH OF NW WISCONSIN FRI AFTERNOON AND
EVENING WITH THE STRONGEST FORCING. HOWEVER..WE HAVE ADJUSTED
TIMING LATER BY 3-5 HOURS /IN LINE WITH NEWEST GUIDANCE/ AND KEPT
WITH VERY LIGHT QPF AMOUNTS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU SEP 11 2014

THE BEGINNING OF THE PERIOD WILL BE COOLER THAN NORMAL. A SURFACE
HIGH PRESSURE RIDGE WILL MOVE THROUGH THE NORTHLAND...RESULTING IN
CLEAR SKIES AND LIGHT WIND SATURDAY MORNING. LOW TEMPERATURES
SATURDAY SHOULD DIP DOWN TO AT LEAST THE UPPER 20S AND LOWER
30S...IF NOT LOWER. A FROST ADVISORY WILL LIKELY BE NEEDED FOR THIS
TIME.

TEMPERATURES WILL REBOUND TO THE UPPER 50S AND LOW 60S OVER THE
WEEKEND. A PASSING TROUGH OF LOW PRESSURE WILL BRING A CHANCE OF
LIGHT SHOWERS SATURDAY NIGHT AND SUNDAY.

HIGH PRESSURE WILL MOVE BACK INTO THE NORTHLAND MONDAY. THERE COULD
BE LIGHT CONVECTIVE SHOWERS IN THE ARROWHEAD DUE TO THE COOL NW FLOW.

AN UPPER LEVEL RIDGE IN THE WESTERN UNITED STATES COULD BEGIN TO
SHIFT INTO THE CENTRAL UNITED STATES DURING THE MIDDLE OF NEXT
WEEK...WHICH WILL LIKELY BRING A WARMING TREND. HIGH TEMPERATURES
MIGHT REBOUND TO THE LOW TO MIDDLE 60S BY WEDNESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1235 AM CDT FRI SEP 12 2014

VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. PERIODS OF LIGHT
FOG WILL BE POSSIBLE OVERNIGHT IN LOW LAYING AREAS...AND MAY AFFECT
THE KHIB AND KHYR TERMINALS. SCATTERED CEILINGS AROUND 6-8 KFT
WILL DRIFT ACROSS THE REGION OVERNIGHT AND FRIDAY. THE COLD AIR
MASS MAY TRIGGER A FEW INSTABILITY SHOWERS FRIDAY AFTERNOON.
HOWEVER...HAVE LEFT ANY MENTION OF PRECIP OUT OF TAF AT THIS TIME.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  36  58  41  62 /   0   0  20  30
INL  33  60  41  58 /   0   0  30  50
BRD  32  60  44  63 /   0   0  10  10
HYR  30  59  40  63 /  10   0  10  30
ASX  33  59  43  63 /  10   0  10  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ010>012-
     018>021-025-026-033>038.

WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ001>004-
     006>009.

LS...NONE.

&&

$$

SHORT TERM...GRANING
AVIATION...GRANING






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