Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 022343
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
643 PM CDT THU JUL 2 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 348 PM CDT THU JUL 2 2015

THE AREA OF HIGH PRESSURE OVER LAKE SUPERIOR EARLIER THIS WEEK IS
GRADUALLY SHIFTING SOUTHEASTWARD AS A MID-LEVEL WAVE APPROACHES FROM
THE NORTH. AS THE HIGH DEPARTS WARMER AIR IS BEING ADVECTED INTO THE
REGION DUE TO WESTERLY LOW/MID LEVEL FLOW...ESPECIALLY IN NORTHERN
MINNESOTA. THIS WARM AIR ADVECTION AT LOW LEVELS WILL HELP TO
STEEPEN LAPSE RATES ALOFT...AND WITH NEARLY NO CAP IN PLACE EXPECT
ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON. A COLD
FRONT ASSOCIATED WITH THIS WAVE WILL MOVE SOUTH THROUGH THE REGION
TOMORROW...PROVIDING BETTER FORCING FOR CONVECTION WHICH WILL RESULT
IN A MORE WIDESPREAD CHANCE FOR SHOWERS AND STORMS...A FEW OF WHICH
COULD BE STRONG. TEMPS REMAINING AT OR ABOVE NORMAL THROUGH THE END
OF THE WEEK.

LATE TODAY...A FEW SHOWERS AND STORMS ACROSS THE ARROWHEAD
REGION...OTHERWISE MOSTLY SUNNY AND WARM. WHILE LARGE SCALE FORCING
IS NOT VERY STRONG...COMBINATION OF WARM AIR ADVECTION AND THE
UNCAPPED ENVIRONMENT SHOULD LEAD TO AT LEAST A FEW SHOWERS AND
STORMS. MLCAPE CAPE VALUES OF 1000-1200 J/KG AND 0-6KM SHEAR OF
20KTS SHOULD BE CAPABLE OF PRODUCING A FEW STRONG STORMS IN A
MULTICELLULAR ENVIRONMENT...WITH THE OUTFLOWS OF INITIAL STORMS THIS
AFTERNOON BEING FOCUS FOR ADDITIONAL STORMS INTO THE EVENING. MAIN
THREAT WILL BE SOME SMALL HAIL AND DOWNPOURS WITH THE STRONGEST
STORMS...BUT GIVEN THE DEEP LAYER SHEAR STORMS SHOULD BE BRIEF IN
DURATION AT ANY ONE LOCATION. OUTSIDE OF THE ARROWHEAD A FEW CU ARE
EXPECTED...MAINLY ACROSS THE REST OF NORTHERN MINNESOTA...WITH JUST
A FEW CLOUDS IN NORTHWEST WISCONSIN WHERE IT WILL NOT BE AS WARM AND
THUS LAPSE RATES NOT AS STEEP. HIGHS IN THE MID 70S ALONG THE
SOUTHERN PORTIONS OF THE CWA AND ACROSS MOST OF INLAND NORTHWEST
WISCONSIN...INTO THE UPPER 70S TO LOW 80S ALONG AND NORTH OF HIGHWAY
2. WESTERLY WINDS WILL EVEN KEEP TEMPS ALONG THE LAKE SUPERIOR
SHORELINE MILD.

TONIGHT...FIRST ROUND OF SHOWERS AND STORMS WILL GRADUALLY MOVE EAST-
SOUTHEAST OVER LAKE SUPERIOR AND DISSIPATE THIS EVENING AHEAD OF THE
NEXT ROUND MOVING IN FROM THE NORTH/NORTHWEST LATER TONIGHT. SKIES
CLEAR SOUTH OF HIGHWAY 2...WITH INCREASING CLOUDS FROM THE
INTERNATIONAL BORDER SOUTH INTO NORTHEAST MINNESOTA AS THE NIGHT
GOES ON AS SHOWERS MOVE ON IN. THIS OVERNIGHT PRECIP WILL BE A
COMBINATION OF TWO FEATURES...A WEAK SFC TROUGH COMING IN FROM THE
WEST AND A COLD FRONT COMING IN FROM THE NORTH. THIS SFC TROUGH IS
EVIDENT IN EASTERN NORTH DAKOTA WITH ONGOING CONVECTION...THE
REMNANTS OF WHICH ARE EXPECTED TO DRIFT INTO THE BORDERLAND REGION
THIS EVENING INTO THE OVERNIGHT HOURS. THE COLD FRONT MOVING IN FROM
THE NORTH WILL THEN PUSH SOUTH THROUGH THE CWA TOWARDS THE MORNING.
COVERAGE OF OVERNIGHT PRECIP IS A BIT UNCERTAIN. WHILE THERE SHOULD
BE ENOUGH ELEVATED INSTABILITY IN THE BORDERLAND TONIGHT TO SUSTAIN
SHOWERS AND POSSIBLE THUNDERSTORM OR TWO...AS THE FEATURE DRIFTS
SOUTH THE ELEVATED INSTABILITY WILL WANE. DOES NOT LOOK LIKE A
STRONG LLJ OVERNIGHT TO SUSTAIN THUNDERSTORMS...BUT ISOLATED SHOWERS
ARE POSSIBLE. OVERNIGHT LOWS IN THE MID TO UPPER 50S DUE TO CLOUD
COVER...INTO THE LOW 50S IN PARTS OF INLAND NORTHWEST WISCONSIN AS
CLOUDS WILL HOLD OFF UNTIL EARLY MORNING HOURS THERE.

FRIDAY...WHILE A FEW SHOWERS MAY BE ONGOING AT DAYBREAK...EXPECT
MORE WIDESPREAD CONVECTION TO DEVELOP IN THE AFTERNOON MAINLY ALONG
AND SOUTH OF HIGHWAY 2. THIS IS MAINLY DEPEND ON THE POSITION OF THE
COLD FRONT...AND IF IT DROPS SOUTH FASTER THAN CURRENTLY ANTICIPATED
THIS WILL IMPACT STORM COVERAGE. CAPE VALUES LOOK TO BE A BIT HIGHER
WITH BETTER MID/UPPER-LEVEL WINDS SUPPORTING AROUND 30KTS 0-6KM
SHEAR...SO IT WILL BE POSSIBLE TO SEE A STRONGER STORM PRODUCE SMALL
HAIL. OTHERWISE SKIES WILL BE SUNNY TOWARDS THE INTERNATIONAL BORDER
BEHIND THE FRONT...AND TEMPERATURES WILL BE WARM EVERYWHERE WITH
HIGHS IN THE UPPER 70S TO NEAR 80.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 348 PM CDT THU JUL 2 2015

HAVE KEPT SMALL POPS OVER NORTHERN WISCONSIN ZONES ON SATURDAY AS
SFC WARM FRONT WILL BE POSITIONED INLAND FROM LAKE SUPERIOR AND
COULD BECOME THE TRIGGER FOR A FEW ISOLATED SHOWERS AND
THUNDERSTORMS DUE TO THE UNSTABLE AIR MASS. LATEST NAM BUFR SOUNDING
AT KHYR SUGGESTS MUCAPE VALUES EXCEED 1000 J/KG WITH A SHALLOW LAYER
OF MID LEVEL MOISTURE TO SUPPORT A FEW SHORT LIVED WEAK CELLS.

MAIN FOCUS IS ON LONG WAVE TROUGH THAT TRANSLATES ACROSS THE
CANADIAN ROCKIES...DEEPENING INTO A CLOSED LOW OVER MANITOBA/WESTERN
ONTARIO SUNDAY. THIS LOW WILL SWEEP A COLD FRONT ACROSS THE
NORTHLAND DURING THE LATE SUNDAY THROUGH MONDAY PERIODS. LATEST LONG
RANGE GUIDANCE CONTINUES TO SHOW A SLOWER TREND WITH THE FRONTAL
PASSAGE AND ASSOCIATED CONVECTION...SO HAVE ADJUSTED POPS
ACCORDINGLY. AT THIS TIME THE BULK OF THE ACTIVITY IS EXPECTED
DURING THE SUNDAY NIGHT THROUGH MONDAY MORNING TIME FRAME. THE
SEVERE POTENTIAL WILL DEPEND GREATLY ON TIMING. FOR NOW...A FEW
STORMS COULD BECOME STRONG SUNDAY EVENING WITH SMALL HAIL AND GUSTY
WINDS.

TEMPERATURES OVER THE WEEKEND WILL BE NEAR TO SLIGHTLY ABOVE NORMAL
WITH HIGHS AROUND 80 IN MOST AREAS. THE EXCEPTION WILL BE IN
LOCATIONS ALONG THE SHORES OF LAKE SUPERIOR WHERE AN ONSHORE FLOW
WILL KEEP READINGS IN THE 60S AND 70S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 638 PM CDT THU JUL 2 2015

VFR CONDITIONS COVERED THE NORTHLAND EARLY THIS EVENING...WITH A
FEW SHOWERS EXITING THE ARROWHEAD. AREA RADARS SHOW MORE SHOWERS
AND THUNDERSTORMS OVER SOUTHERN MANITOBA AND NORTHWEST ONTARIO
INTO EASTERN NORTH DAKOTA...WHICH WILL GRADUALL MOVE INTO NORTHERN
MINNESOTA OVERNIGHT. OVERALL WE EXPECT VFR CONDITIONS THROUGH THE
PERIOD AND HAVE ADDED A MENTION OF THUNDERSTORMS TO MOST TAF
SITES. WE MAY HAVE TO ADJUST THE TIMING SOME AS WE PROGRESS
THROUGH THE PERIOD.

SATELLITE IMAGERY SHOWS PLENTY OF SMOKE OVER THE REGION...AND WE
MAY SEE SOME HAZE DEVELOP OVERNIGHT IN SPOTS. EXPECT SOUTHWEST
WINDS TONIGHT TO TURN NORTHWEST AS A COLD FRONT DROPS THROUGH THE
NORTHLAND ON FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  59  78  56  73 /  10  40  20  10
INL  58  77  51  81 /  40  20  10  10
BRD  55  79  56  83 /  10  40  10  10
HYR  55  78  55  79 /   0  50  30  20
ASX  57  77  55  73 /  10  40  40  10

&&

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

$$

SHORT TERM...JJM
LONG TERM...GRANING
AVIATION...MELDE


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