Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 070856
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
356 AM CDT THU MAY 7 2015

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM CDT THU MAY 7 2015

AT 345 AM...WE SAW ONE AREA OF SHOWERS EXITING THE INTERNATIONAL
BORDER REGION...WHILE A NEW AREA OF SHOWERS AND POSSIBLE STORMS
WAS MOVING INTO THE SOUTHERN CWA. AN AREA OF PARTIAL CLEARING HAD
DEVELOPED IN BETWEEN THOSE TWO AREAS OF PRECIPITATION.
TEMPERATURES RANGED FROM THE 40S NEAR LAKE SUPERIOR TO THE LOWER
60S IN THE SOUTHERN PORTION OF THE CWA.

THE FOCUS FOR THE PERIOD FROM TODAY THROUGH FRIDAY...AND ESPECIALLY
FOR TODAY...IS TRYING TO RESOLVE THE OVERALL PRECIPITATION POTENTIAL
AND AMOUNTS. AN ANALYSIS OF THE HRRR/RAP/WRF AND THE NAM/GFS/ECMWF
INDICATED NONE OF THE MODELS HAD A GOOD HANDLE ON THE CURRENT
PRECIPITATION AREA...WITH MOST OF THE MODELS TOO SLOW WITH THE
CURRENT SHOWERS MOVING INTO THE SOUTHERN CWA. OVERALL...THINK THE
MODELS DO CATCH UP AND THE TREND FOR INCREASING PRECIPITATION
TODAY SOUNDS LIKE A REASONABLE SCENARIO. WILL GENERALLY HAVE HIGH
POPS ACROSS THE CWA TODAY AND TONIGHT...WITH CHANCES INCREASING
THROUGHOUT THE MORNING TODAY. HIGH RESOLUTION MODELS SUCH AS THE
4KM NMM WRF AND THE HRRR INDICATE THE MODE OF PRECIPITATION SHOULD
BECOME MORE CELLULAR DURING THE DAY. SPC HAS A PORTION OF OUR AREA
IN THE MARGINAL SEVERE WEATHER THREAT AREA...AND THAT SEEMS
REASONABLE GIVEN THE BETTER CHANCE FOR SEEING SOME DAYTIME HEATING
AND PARTIAL SUNSHINE IN THE SOUTHERN PORTION OF THE CWA.
PRECIPITABLE WATER VALUES THIS MORNING ARE GENERALLY IN THE 1.2
INCH RANGE. A FORMIDABLE LLJ OF UP TO 50 KT WAS EVIDENT THROUGHOUT
THE PLAINS AND UPPER MIDWEST.

TODAY...WILL GO WITH FAIRLY HIGH POPS. PRECIPITATION WILL COME IN
WAVES AND INCREASE THROUGHOUT THE DAY. HIGHS SHOULD GENERALLY BE
IN THE 70S...ALTHOUGH SOME 60S ARE POSSIBLE IN SPOTS...WITH 40S
AND 50S NEAR THE LAKE. COULD BE SOME STRONG THUNDERSTORMS DURING
THE LATTER PORTION OF THE DAY...AND POSSIBLY AN ISOLATED SEVERE
THUNDERSTORM ACROSS THE SOUTHEAST HALF OF THE CWA.

TONIGHT...SHOWERS AND THUNDERSTORMS WILL BE LIKELY. A FEW STRONG
STORMS WILL AGAIN BE POSSIBLE DURING THE EVENING...ESPECIALLY
ACROSS THE SOUTHEASTERN PORTION OF THE CWA. BY 06Z FRIDAY...THE
COLD FRONT SHOULD REACH THE DULUTH AREA...AND IT SHOULD JUST ABOUT
CLEAR THE SOUTHEAST CWA BY 12Z FRIDAY. WINDS WILL SWITCH TO THE
NORTHWEST BEHIND THE FRONT.

FRIDAY...THE SHOWERS AND STORMS WILL GRADUALLY DIMINISH FROM THE
WEST. ONLY A FEW SHOWERS WILL LINGER FAR EAST INTO THE AFTERNOON.
DRIER AIR WILL PUSH IN FROM THE NORTHWEST...AS DRIER AND COOLER
AIR SPREADS INTO THE AREA FROM CANADIAN HIGH PRESSURE. HIGHS WILL
BE IN THE 50S FOR MOST OF NE MN...WITH SOME 60S IN WI.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU MAY 7 2015

HIGH PRESSURE AT THE SURFACE WILL BE BUILDING IN ACROSS SRN MANITOBA
AND WRN ONTARIO FRIDAY NIGHT AND SATURDAY...AND INTO LAKE SUPERIOR
SAT NIGHT. AS THE HIGH SHIFTS SLIGHTLY TO THE EAST THE NEXT
SIGNIFICANT LOW PRESSURE SYSTEM WILL MOVE FROM THE SRN PLAINS INTO
THE UPPER MIDWEST BY LATE SUNDAY NIGHT/MON MORNING. THE COMBINATION
OF THE SFC HIGH AND APPROACHING LOW TO THE SOUTH WILL INDUCE A
PERSISTENT E/NE WIND OFF LAKE SUPERIOR FRI NIGHT THROUGH MONDAY
NIGHT. THE APPROACHING SYSTEM WILL ONCE AGAIN DRAW UP A LARGE SUPPLY
OF MOISTURE FROM THE SOUTH AND DEPOSIT IT IN THE FORM OF WIDESPREAD
RAIN SHOWERS ACROSS THE NORTHLAND THROUGH THE DAY SUNDAY AND
CONTINUING INTO MONDAY AS THE SYSTEM WRAPS UP MOVING INTO THE GREAT
LAKES. THIS SYSTEM WILL BE FAIRLY DYNAMIC WITH A STRONG WARM FRONT
OUT AHEAD OF THE LOW...WHICH COULD BE CAPABLE OF PRODUCING SCATTERED
THUNDERSTORMS WITH THE SHOWERS DURING THE DAY SUNDAY. THE SYSTEM
THEN BEGINS TO LOOK MORE LIKE A WINTER-TYPE LOW AS AN AREA OF COLDER
AIR FILLS IN ON THE BACK SIDE...AND A TROWAL-LOOKING FEATURE
DEVELOPS TO THE EAST WITH AN AREA OF ROBUST STRATIFORM RAIN FORMING
IN THE DEFORMATION ZONE ACROSS NRN MN. THE RAIN SHOULD LINGER INTO
LATE MONDAY AND EARLY TUESDAY AS THE COLD AIR CONTINUES TO DROP IN
ACROSS THE UPPER MIDWEST BEHIND THE DEPARTING SYSTEM. THE AMT AND
DEPTH OF THE COLD AIR COULD ACTUALLY CHANGE OVER TO RAIN OR MIX WITH
SNOW AT TIMES TUESDAY MORNING. NO ACCUMULATION IS EXPECTED AT THIS
TIME. HIGH PRESSURE WILL BUILD IN BEHIND THE SYSTEM INTO THE MIDDLE
OF THE WEEK...BUT ONLY FOR A BRIEF PERIOD AS THE NEXT WEAK INVERTED
TROUGH SLIDES IN FROM THE WEST WITH ADDITIONAL CHANCES FOR LIGHT
RAIN.

TEMPERATURES WILL BE NOTICEABLY COOLER THROUGH MUCH OF THE EXTENDED
PERIOD...ESPECIALLY AROUND THE TWIN PORTS AREA WITH A PERSISTENT
E/NE WIND OFF LAKE SUPERIOR. WHILE AREAS INLAND COULD SEE UPPER 50S
AND 60S AT TIMES...LOCATIONS CLOSER TO THE LAKE WILL ONLY SEE 40S
AND LOWER 50S DURING THE DAY. THE PRESENCE OF A LAKE BREEZE WILL
MAKE IT SEEM EVEN COLDER. OVERNIGHT LOWS WILL GENERALLY BOTTOM OUT
IN THE 30S AND LOWER 40S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1245 AM CDT THU MAY 7 2015

MAINLY VFR-MVFR CEILINGS AND VISIBILITIES ACROSS NORTHERN
MINNESOTA AND NORTHWEST WISCONSIN AS OF 05Z. SOME ISOLATED SHOWERS
EXPECTED THE NEXT FEW HOURS...BRINGING MVFR CEILINGS AND
VISIBILITIES. WITH THE MOISTURE CONTINUING TO PUMP UP INTO THE
AREA...EXPECT SOME LOWERING OF CLOUD BASES...AND TERMINALS SHOULD
SEE DEVELOPMENT OF MVFR CEILINGS THE NEXT FEW HOURS. A STRONG LOW
LEVEL JET OF 35-45KTS HAS PRODUCED LLWS OVER THE TERMINALS WHICH
SHOULD CONTINUE THROUGH APPROXIMATELY 12Z WHEN SURFACE WINDS
INCREASE. THE NEXT WAVE OF SHOWERS TO PUSH THROUGH THE TERMINALS
BEGINNING AROUND 09Z...BRINGING IFR-MVFR CEILINGS AND VISIBILITIES
FOR A FEW HOURS...BEFORE ONCE AGAIN RETURNING TO VFR. ANOTHER WAVE
OF SHOWERS WITH SOME THUNDERSTORMS WILL PUSH THROUGH THE TERMINALS
BEGINNING AROUND 15Z...AND MAY BRING A PERIOD OF THUNDER WITH MVFR
CEILINGS AND IFR VISIBILITIES WITH STRONGER CELLS.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  70  47  58  40 /  80  80  20   0
INL  70  42  53  34 /  80  60  20   0
BRD  72  47  57  39 /  80  70  10   0
HYR  76  53  63  41 /  80  80  20   0
ASX  79  52  62  37 /  70  70  30  10

&&

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

$$

SHORT TERM...DAP
LONG TERM...BJT
AVIATION...LE





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