Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 030526
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1226 AM CDT MON AUG 3 2015

.UPDATE...
ISSUED AT 909 PM CDT SUN AUG 2 2015

DULUTH CWA WILL REMAIN IN DEEP NW FLOW UNDERNEATH THE SOUTHWEST
PERIPHERY OF DEEP UPPER LOW TO OUR NORTH IN CANADA THROUGH
MONDAY..WITH TEMPS ALOFT GRADUALLY COOLING OVER THE NEXT 24 HOURS.
MAIN ISSUE FOR TONIGHT AND TOMORROW IS THE RATHER EXPANSIVE CLOUD
SHIELD EVIDENT IN SAT IMAGERY UPSTREAM FROM US AND ITS POTENTIAL
AFFECT ON TEMPS AND MIXING DEPTH ON MONDAY..WHICH WILL ALSO HAVE
SOME IMPACT ON WINDS/GUSTS AND COVERAGE OF SHOWERS.

OF IMMEDIATE CONCERN..WE DID INCREASE SKY COVER RATHER
SUBSTANTIALLY ON THE UPDATE THIS EVENING ACROSS MUCH OF OUR
CWA..AS CLOUDS UPSTREAM WILL CLEARLY OVERSPREAD MUCH OF NE MN
OVERNIGHT. CONFIDENCE ON EXACTLY HOW FAR SOUTH TO BRING THE
LEADING EDGE OF THE OVERCAST IS NOT ESPECIALLY HIGH..BUT GIVEN
SUSTAINED COLD ADVECTION THROUGH MIDDAY MONDAY BELOW 700 MB..WE
WOULD NOT BE SURPRISED TO SEE THE CLOUDS PUSH ACROSS MOST OF THE
CWA..INCLUDING MOST OF NW WISCONSIN BY LATE MORNING TOMORROW. IT
IS ALSO NOT OUT OF THE QUESTION THAT THERE COULD BE A FEW LIGHT
SHOWERS OVERNIGHT..ESPECIALLY ANYWHERE NORTH OF THE HIGHWAY 2
CORRIDOR AND IN PARTICULAR OVER THE ARROWHEAD AND BOUNDARY WATER
REGION.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 244 PM CDT SUN AUG 2 2015

A COLD FRONT HAS MOVED THROUGH THE REST OF OUR NORTHWEST WISCONSIN
ZONES AS OF 20Z. HOWEVER...A SHORTWAVE WAS DROPPING SOUTHEAST
THROUGH THE REGION. THE SHORTWAVE AS WELL AS RESIDUAL OUTFLOW
BOUNDARIES FROM EARLIER CONVECTION CONTINUED TO AID IN PRODUCING SHOWERS
AND THUNDERSTORMS FROM THE IRON RANGE INTO NORTHWEST WISCONSIN.
ALTHOUGH THE BETTER RISK FOR SEVERE STORMS HAS SHIFTED SOUTH OF
THE NORTHLAND...MLCAPE OF 1500-2000J/KG AND 50KT OF DEEP LAYER
SHEAR OVER NORTHWEST WISCONSIN IS STILL PRESENT. THERE COULD
STILL BE A STRONG STORM MAINLY SOUTHEAST OF A HAYWARD TO IRONWOOD
LINE THROUGH ABOUT 6 PM.

THE SHOWERS AND STORMS SHOULD EXIT THE NORTHLAND EARLY THIS
EVENING...THEN AS COLDER AIR CONTINUES SOUTH AND MOISTURE
INCREASES THERE COULD BE SOME SHOWERS THAT FORM OVER THE BORDER
REGION.

CLOUDS WILL CONTINUE TO DROP SOUTH ON MONDAY WITH SOME SHOWERS
POSSIBLE IN SPOTS UNDER THESE COLDER TEMPERATURES ALOFT. HIGHS
WILL ONLY BE IN THE MID 60S FAR NORTH AND THE LOWER TO MID 70S
ACROSS OUR SOUTHERN ZONES.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 244 PM CDT SUN AUG 2 2015

SUMMARY...THE NORTHLAND WILL BE IN A COOL NW FLOW PATTERN FOR THE
MIDDLE OF THE WEEK...KEEPING THE NORTHLAND SLIGHTLY COOLER THAN
NORMAL. TEMPERATURES MIGHT REBOUND BACK TO NORMAL BY LATE THIS WEEK.
THUNDERSTORMS ARE POSSIBLE LATER IN THE WEEK.

TUESDAY...SURFACE HIGH PRESSURE WILL BEGIN TO MOVE INTO THE
NORTHLAND. THE COOL NW FLOW ALOFT...THOUGH...WILL HELP DEVELOP
SCT/BKN CUMULUS CLOUDS BY THE EARLY AFTERNOON. THE CLOUD COVER WILL
FURTHER LIMIT DAYTIME HEATING...ESPECIALLY OVER THE ARROWHEAD.
SHOWERS ARE POSSIBLE OVER THE ARROWHEAD AND IN THE ASHLAND AND IRON
COUNTY AREAS OF NW WISCONSIN. LEANED ON THE COOLER GFS FOR HIGH
TEMPERATURES...WITH HIGHS PRIMARILY IN THE UPPER 60S AND LOW 70S.

WEDNESDAY...SURFACE HIGH PRESSURE SHOULD HELP KEEP THE NORTHLAND DRY
AND A BIT SUNNIER THAN TUESDAY. TEMPERATURES WILL BE A BIT WARMER IN
THE LOWER 70S. CUT BACK ON PCPN CHANCES BASED ON THE DRIER 12Z
GFS/ECMWF/GEM RUNS.

LATE WEDNESDAY/THURSDAY...THERE IS SOME UNCERTAINTY AS TO PCPN
CHANCES. THE GFS IS INDICATING SURFACE HIGH PRESSURE WILL KEEP THE
NORTHLAND DRY. HOWEVER...THE ECMWF AND GEM ARE INDICATING A
POTENTIAL STORM COMPLEX DEVELOPING EAST OF AN UPPER LEVEL RIDGE AND
NEAR THE ND/MN/MANITOBA/ONTARIO BORDER REGION WEDNESDAY NIGHT INTO
THURSDAY MORNING...POTENTIALLY AFFECTING THE NW FORECAST AREA. KEPT
THE FORECAST MOSTLY DRY FOR NOW SINCE THE UPPER LEVEL RIDGE WOULD
LIKELY HELP PREVENT MUCH FROM DEVELOPING...BUT WILL NEED TO KEEP AN
EYE ON SUBSEQUENT MODEL TRENDS. THERE ARE LOW CHANCES OF PCPN ACROSS
THE FAR SOUTHERN FORECAST AREA FOR WEDNESDAY NIGHT AND
THURSDAY...BUT MIGHT BE ABLE TO REMOVE THIS COMPLETELY WITH
SUBSEQUENT FORECASTS. THE LOW CHANCES ARE TO ACCOUNT FOR THE WAVE
THAT WILL LIKELY EJECT INTO THE PLAINS DURING THE WEDNESDAY/THURSDAY
TIME FRAME...BUT THE MODELS ARE CONTINUING TO TREND THIS FEATURE
FARTHER SOUTH AND AT AN EARLIER TIME. THE LATEST MODELS PRIMARILY
INDICATE THIS WAVE MOVING THROUGH SOUTHERN MINNESOTA/IOWA...OR EVEN
FARTHER SOUTH...ON WEDNESDAY. NEED TO MAINTAIN SOME LOW PCPN CHANCES
UNTIL CONFIDENCE INCREASES ON THE SOONER AND MORE SOUTHERN TRACK.

FRIDAY/SATURDAY...WARM AND MORE HUMID SOUTHERLY FLOW WILL LIKELY
DEVELOP ACROSS THE NORTHLAND AS LOW PRESSURE APPROACHES FROM THE
WEST. SHOWERS AND STORMS ARE POSSIBLE. TEMPERATURES MIGHT RETURN TO
NEAR NORMAL WITH HIGHS IN THE MIDDLE 70S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1226 AM CDT MON AUG 3 2015

BROAD NW TO WNW SURFACE FLOW WILL PERSIST THROUGH THIS TAF PERIOD AS
HIGH PRESSURE CONTINUES TO BUILD SOUTHWARD INTO THE PLAINS..AND THE
WRN GREAT LAKES REGION REMAINS WITHIN THE FAIRLY TIGHT GRADIENT
BETWEEN THE RIDGE TO OUR WEST AND DEEPENING LOW PRESSURE OVER
EASTERN ONTARIO AND QUEBEC THRU MONDAY. 5-10 KT WNW WINDS OVERNIGHT
SHOULD BECOME MORE NORTHWESTERLY 13-16Z MONDAY WITH GUSTS IN THE 17-
22KT RANGE DEVELOPING AGAIN TOMORROW..ESPECIALLY AT KDLH/KBRD.

WIDESPREAD CLOUD COVER IS EXPECTED FOR MOST OF MONDAY AS COLD
ADVECTION PERSISTS BELOW 700 MB. HOWEVER..CEILINGS ARE EXPECTED TO
GENERALLY BE VFR..BUT A PERIOD OF MVFR CONDITIONS AT KINL AND
PERHAPS KHIB/KDLH IS POSSIBLE. WITH LOW LEVEL LAPSE RATES STEEPENING
OVER THE NEXT 12-18 HOURS..EVEN IN THE ABSENCE OF FULL SURFACE
HEATING..SCATTERED SHOWERS AND PERHAPS EVEN A THUNDERSTORM APPEAR
POSSIBLE ON MONDAY AFTERNOON.  TERMINALS WITH THE HIGHEST
PROBABILITY OF BEING AFFECTED BY PRECIP ON MONDAY ARE
KINL/KHIB/KDLH.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  51  70  51  72 /  10  10   0   0
INL  45  67  44  71 /   0  10   0   0
BRD  50  75  52  75 /   0   0   0  10
HYR  48  70  46  74 /  10  10   0   0
ASX  52  68  50  73 /   0  20   0  10

&&

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

$$

UPDATE...MILLER
SHORT TERM...MELDE
LONG TERM...GROCHOCINSKI
AVIATION...MILLER


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