Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 020002 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
702 PM CDT SAT AUG 1 2015

.UPDATE...
ISSUED AT 641 PM CDT SAT AUG 1 2015

UPDATED AVIATION DISCUSSION FOR 00Z TAF ISSUANCE BELOW.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 258 PM CDT SAT AUG 1 2015

FORECAST FOCUS IN THE SHORT TERM WILL BE ON SHOWER/THUNDERSTORM
CHANCES AND STRENGTH OF THE STORMS...MAINLY TONIGHT.

WE RELIED ON A BLEND OF THE MODELS INCLUDING THE CAMS. AN AREA OF
LOW PRESSURE WAS NEAR THE SC NORTH DAKOTA/NC SOUTH DAKOTA BORDER
AS OF 20Z WITH A WARM FRONT EXTENDING INTO SOUTHWEST MINNESOTA.
MORE STABLE AIR WAS IN PLACE OVER THE NORTHLAND THIS AFTERNOON WITH
MUCAPE VALUES FROM SPC MESO ANALYSIS LESS THAN 250 J/KG FOR MOST
AREAS. THE MORE STABLE AIR AND UPPER FLOW THAT HAS VEERED A BIT
AND WAS LESS CYCLONIC OVER NORTHEAST MINNESOTA HAS PREVENTED
SHOWERS/STORMS FROM FORMING. A FEW SHOWERS WERE OCCURRING JUST
SOUTHWEST OF THE BRAINERD LAKES REGION AS OF 2020Z...AND WAS AT
LEAST PARTIALLY DUE TO INCREASING FGEN.

THE LOW WILL MOVE INTO CENTRAL TO WEST CENTRAL MINNESOTA BY 12Z
SUNDAY WITH THE WARM FRONT LIFTING NORTH BUT REMAINING SOUTH OF
THE NORTHLAND. INCREASING FGEN AND MOISTURE ADVECTION DUE TO
STRENGTHENING LOW LEVEL FLOW...925MB WINDS OF 35 TO 40 KT...WILL
AID IN DEVELOPING SHOWERS/STORMS TONIGHT OVER THE SOUTHERN HALF OF
THE NORTHLAND. INSTABILITY WILL ALSO INCREASE TONIGHT...ESPECIALLY
OVER SOUTHERN AREAS. STRONG MID LEVEL FLOW WILL CONTINUE CREATING
PLENTY OF SHEAR. A STRONG TO SEVERE STORM REMAIN POSSIBLE OVER OUR
SOUTHERN ZONES...ROUGHLY SOUTH OF A LEECH LAKE TO PARK FALLS LINE.

MORE SHOWERS AND SOME THUNDERSTORMS WILL OCCUR OVER OUR FAR
NORTHERN ZONES TONIGHT AND WE HAVE LIKELY POPS UP THERE AS THE
COLD FRONT DROPS SOUTH TOWARD THE BORDER REGION. THE STABILITY
WILL BE HIGHER UP THERE...SO THE RISK OF SEVERE STORMS IS LOWER
THAN FURTHER SOUTH.

AS THE LOW SWINGS EAST AND SOUTH OF THE NORTHLAND SUNDAY...DRIER
AND COOLER AIR WILL START TO MOVE IN. THIS SHOULD CAUSE THE CHANCE
FOR SHOWERS/STORMS TO DIMINISH FROM NORTHWEST TO SOUTHEAST WITH
NORTHERN AREAS BECOMING DRY BY AFTERNOON. HIGHS ARE STILL EXPECTED
TO BE IN THE LOWER TO MID 70S NORTH AND AROUND 80 SOUTH...BUT
TEMPERATURES WILL START TO COOL LATER IN THE AFTERNOON FROM NORTH
TO SOUTH. IT WILL BECOME BREEZY OVER NORTHEAST MINNESOTA AS THE
LOW PULLS AWAY SUNDAY AFTERNOON.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 258 PM CDT SAT AUG 1 2015

SUMMARY...THE PERIOD WILL BEGIN WITH A COLD SPELL. THE NORTHLAND CAN
EXPECT COOLER THAN NORMAL WEATHER FOR AT LEAST THE MONDAY THROUGH
WEDNESDAY TIMEFRAME DUE TO A COOL NW FLOW PATTERN. MONDAY AND
TUESDAY SHOULD BE COOLER THAN WEDNESDAY. THERE IS UNCERTAINTY ABOUT
THE WEATHER FOR THE LATTER HALF OF THE WEEK. EARLIER MODEL RUNS HAD
BEEN INDICATING SHOWERS AND STORMS...BUT THE LATEST GFS/ECMWF RUNS
ARE TRENDING TOWARDS A DRIER FORECAST.

MONDAY...THE NORTHLAND WILL BE UNDER RELATIVELY COLD NW FLOW. THE
850 HPA TEMPERATURES WILL RANGE FROM ABOUT 5 DEGREES CELSIUS IN THE
ARROWHEAD TO ABOUT 9 DEGREES CELSIUS IN OUR FAR SW FORECAST AREA.
THE COLD AND RELATIVELY HUMID FLOW SHOULD RESULT IN WIDESPREAD
BKN/OVC CUMULUS CLOUD COVER BY THE EARLY AFTERNOON. SCATTERED
SHOWERS WILL LIKELY DEVELOP OVER THE NORTHERN AND FAR SE FORECAST
AREA DURING THE AFTERNOON THROUGH EARLY EVENING. THE CLOUD COVER
WILL MAKE IT DIFFICULT TO HEAT UP AND BUILD ENOUGH INSTABILITY FOR
THUNDER. WHILE CANNOT RULE OUT STRAY THUNDER...SINCE THE GFS/SREF DO
NOT HAVE ANY MUCAPE...DECIDED TO REMOVE THE THUNDER IN THE PREVIOUS
FORECAST. LEANED ON THE COOLER GFS AND GFS MOS GUIDANCE SINCE THE
GFS HAS A TENDENCY TO DO BETTER WITH COLD SPELLS...AND BECAUSE OF
THE LIKELY CLOUD COVER. THIS RESULTED IN LOWERING THE TEMPERATURE
FORECAST BY A FEW DEGREES. HIGH TEMPERATURES WILL STRUGGLE TO REACH
THE UPPER 60S AND LOW 70S...AND BARELY REACH THE LOW 60S IN THE
NORTHERN ARROWHEAD.

TUESDAY...THE DAY WILL BE SOMEWHAT SIMILAR TO MONDAY...BUT NOT AS
CLOUDY AND NOT WITH AS EXTENSIVE OF PCPN CHANCES. WHILE THE
GFS/ECMWF INDICATE THE 850 HPA TEMPERATURES ON TUESDAY MORNING WILL
BE SIMILAR TO MONDAY...THE 850 HPA TEMPERATURES WILL WARM UP TO
ABOUT 6 TO 10 DEGREES CELSIUS BY THE LATE AFTERNOON. THIS SHOULD
RESULT IN SLIGHTLY WARMER TEMPERATURES THAN MONDAY. SHOWERS ARE
POSSIBLE IN THE NORTHERN ARROWHEAD.

WEDNESDAY...SURFACE HIGH PRESSURE WILL MOVE INTO NORTHLAND TUESDAY
NIGHT INTO EARLY WEDNESDAY. THE COOL NW FLOW PATTERN WILL BEGIN TO
COME TO AN END. THIS SHOULD HELP PROVIDE A SUNNIER DAY FOR THE
NORTHLAND. THE EXTRA SUN AND SLIGHTLY WARMER 850 HPA TEMPERATURES
SHOULD HELP THE HIGHS REACH THE UPPER 60S AND LOW 70S.

LATE WED/THURS/FRI...LATEST GEM/GFS/EURO DIVERGE ON THE EVOLUTION OF
A SHORTWAVE EJECTING ON TOP OF THE BUILDING RIDGE OVER THE NORTHERN
PLAINS/NORTHERN ROCKIES. GEM IS MOST AGGRESSIVE BRINGING A COMPLEX
THROUGH THE CWA...WHICH IS SIMILAR TO THE PREVIOUS EURO RUN. WHEREAS
THE GFS AND CURRENT EURO KEEP THINGS FURTHER SOUTH. WILL NEED TO
MONITOR THE SOUTHERLY TREND...HOWEVER DUE TO THE GEM...LEFT IN CHANCE
POPS WITH A SLIGHT CHANCE OF SOME THUNDER. HIGH TEMPERATURES WILL
BE BELOW NORMAL DURING THIS PERIOD WITH HIGHS IN THE UPPER 60S TO
LOW 70S. EXPECT LOWS RANGING FROM THE UPPER 40S TO MID 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 702 PM CDT SAT AUG 1 2015

WARM FRONTAL BOUNDARY JUST TO THE SOUTH OF THE KBRD TO KHYR AREAS
CONTINUES TO BE MONITORED FOR CONVECTIVE DEVELOPMENT THIS
EVENING..BUT CHANCES OF SUSTAINED DEVELOPMENT APPEAR QUITE LOW AND
WE HAVE CAUTIOUSLY REMOVED THE MENTION OF VICINITY SHOWERS/THUNDER
AT KBRD/KHYR FOR THIS EVENING. STILL..THERE IS A SMALL CHANCE
THAT STORMS COULD INITIATE WITHIN LOW LEVEL FRONTOGENETIC REGIME
ALONG/NORTH OF THE FRONTAL ZONE IN THE 01-05Z TIME FRAME.
OTHERWISE..VFR CONDITIONS SHOULD PREVAIL UNTIL MORE ORGANIZED
SHOWER/TSTORM ACTIVITY ASSOCIATED WITH THE MAIN UPPER WAVE AND
SURFACE FRONT ARRIVE AFTER 06-08Z..THIS IS EXPECTED TO EVOLVE OUT
OF THE ND/MB/SK BORDER AREA WHERE STORMS ARE TRYING TO FIRE
CURRENTLY. BEST CHANCES FOR PRECIP AT THE DULUTH TERMINALS APPEAR
TO BE BETWEEN ROUGHLY 08-15Z. THEREAFTER..WINDS WILL TURN
NORTHWEST BEHIND THE FRONT..AND COULD BECOME GUSTY AFTER 18Z
SUNDAY AS SKIES CLEAR FROM THE WEST..ALLOWING DEEPER MIXING DURING
THE AFTERNOON.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  61  79  54  69 /  40  40   0  20
INL  54  73  48  65 /  60  40   0  20
BRD  59  81  54  75 /  30  20   0   0
HYR  58  81  50  71 /  40  40   0  20
ASX  59  80  53  70 /  40  50   0  10

&&

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

$$

SHORT TERM...MELDE
LONG TERM...GROCHOCINSKI/WL
AVIATION...MILLER



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