Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 060423
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1123 PM CDT SUN JUL 5 2015

.UPDATE...
ISSUED AT 1123 PM CDT SUN JUL 5 2015

SEVERE THUNDERSTORM WATCH WAS ALLOWED TO EXPIRE ON TIME GIVEN
DECREASE IN STORM INTENSITY OVER THE PAST HOUR OR SO. CLEANED UP
THE GRIDS TO BETTER MATCH CURRENT RADAR. EXPECT OVERNIGHT
RAINFALL TO BE FOCUSED ACROSS THE INTERSTATE 35 CORRIDOR EAST
ACROSS NORTHWEST WISCONSIN...WITH ANOTHER ROUND EXPANDING INTO
NORTHEAST MINNESOTA TOMORROW. ALSO ADDED SOME FOG OVER THE
LAKE.

&&

.SHORT TERM...(THROUGH TONIGHT)
ISSUED AT 249 PM CDT SUN JUL 5 2015

THE FOCUS REMAINS ON THE RISK OF SEVERE WEATHER AND HEAVY RAIN
LATER THIS AFTERNOON INTO TONIGHT WITH AN APPROACHING COLD FRONT
FROM THE WEST. ONLY MADE RELATIVELY MINOR CHANGES TO THE TIMING
OF PCPN FROM THE FORECAST FROM EARLY THIS MORNING...BUT DID ADD
SEVERE WORDING TO THE FORECAST FOR THIS AFTERNOON AND EVENING TO
BETTER REFLECT THE HIGHER CONFIDENCE IN THE POTENTIAL FOR SEVERE
WEATHER.

AS OF 245 PM...A NEARLY STACKED LOW PRESSURE SYSTEM OVER THE
WESTERN HUDSON BAY AREA WAS LIFTING TO THE NE WITH A 100 KNOT JET
STEERING THE SYSTEM. ITS COLD FRONT / TROUGH EXTENDED SOUTHWEST
THROUGH FAR NW ONTARIO...FAR NW MINNESOTA...AND EASTERN NORTH
DAKOTA...TO A LOW PRESSURE CENTER IN THE HIGH PLAINS OF SOUTH
DAKOTA AND NEBRASKA. A POTENT SHORTWAVE WAS ROUNDING THE BASE OF
THE UPPER LEVEL TROUGH OVER SOUTH CENTRAL CANADA. A DECAYING
MESOSCALE CONVECTIVE COMPLEX WAS MOVING THROUGH NW MINNESOTA...FAR
SE MANITOBA...AND NW ONTARIO. THE MCS WAS APPROACHING NORTH
CENTRAL MINNESOTA. THE NORTHLAND HAD WARM AND HUMID SOUTHERLY FLOW
WITH PARTLY TO MOSTLY CLOUDY SKIES. MUCH OF THE CLOUD COVER WAS
CIRRUS. TEMPERATURES WERE IN THE UPPER 70S AND LOW 80S WITH DEW
POINT TEMPERATURES PRIMARILY IN THE MIDDLE TO UPPER 60S. THE
WARMEST AND MOST HUMID CONDITIONS WERE ACROSS THE WESTERN FORECAST
AREA AS HEAT AND HUMIDITY POOLED AHEAD OF THE APPROACHING COLD
FRONT AND MCS FROM THE WEST. THE SOUTHERLY WIND SPEEDS WERE ABOUT
5 TO 15 MPH WITH GUSTS AROUND 20 MPH.

MIDDLE OF THIS AFTERNOON...THE MCS MOVING THROUGH NW MINNESOTA
SEEMS TO HAVE WEAKENED FROM EARLIER THIS MORNING...WHEN THERE WERE
REPORTS OF STRONGER WINDS. HOWEVER...THE MCS WILL BE MOVING INTO
AREAS OF NORTH CENTRAL MINNESOTA WITH GREATER AMOUNTS OF
INSTABILITY...ABOUT 1500 J/KG OF MIXED LAYER CAPE. THE STORMS
COULD REINTENSIFY AS THEY MOVE INTO THE NW FORECAST AREA.
ALSO...ISOLATED SUPERCELLS COULD FORM AHEAD OF THE APPROACHING
MCS. THE NW FORECAST AREA WILL HAVE DEEP LAYER WIND SHEAR (0 TO 6
KM) OF ABOUT 30 TO 40 KNOTS...SUFFICIENT FOR SHORT LIVED
SUPERCELLS. THE NAM12 AND RAP13 SOUNDINGS INDICATE RELATIVELY FAT
CAPE PROFILES FOR HAIL GROWTH...BUT THE RELATIVELY HIGH FREEZING
LEVELS AROUND 13000 FT AGL AND WARM/HUMID LOW LEVEL ATMOSPHERE
COULD CONTRIBUTE TO SIGNIFICANT MELTING OF HAILSTONES BEFORE THEY
HIT THE GROUND.

LATE THIS AFTERNOON AND THIS EVENING...MOST HIGH RESOLUTION
MODELS INDICATE THERE WILL INCREASING DEVELOPMENT AND COVERAGE OF
SHOWERS AND THUNDERSTORMS IN NE MINNESOTA AHEAD OR NEAR THE
APPROACHING COLD FRONT...WHICH WILL BEGIN TO MOVE INTO THE WESTERN
FORECAST AREA THIS EVENING. THERE WILL BE A RISK OF SEVERE WEATHER
OVER THE WESTERN HALF OF THE FORECAST AREA. BY THIS
EVENING...MIXED LAYER CAPE COULD BE AROUND 2000 TO 2500 J/KG IN
SOME AREAS...IN PARTICULAR THE SW AND WEST CENTRAL FORECAST AREA.
THE COMBINATION OF THIS AMPLE INSTABILITY AND DEEP LAYER WIND
SHEAR OF 30 TO 40 KNOTS COULD RESULT IN THE DEVELOPMENT OF
DISCREET...SHORT LIVED SUPERCELLS OVER THE WESTERN FORECAST
AREA...AND THEN ALSO THE CENTRAL FORECAST AREA. FORTUNATELY...THE
BETTER WIND SHEAR WILL TRAIL BEHIND THE COLD FRONT. THE MAIN
THREATS FROM ANY SEVERE WEATHER WILL BE DAMAGING WINDS AND LARGE
HAIL...BUT AS MENTIONED BEFORE...THE HAIL THREAT MAY BE SUPPRESSED
BY THE RELATIVELY HIGH FREEZING LEVELS AND WARM AND MOIST LOW
LEVEL ATMOSPHERE. ANOTHER THREAT WILL BE HEAVY RAIN. THE
RAP13/NAM12 INDICATE PRECIPITABLE WATER VALUES WILL BEGIN TO
APPROACH 1.9 OR 2 INCHES TONIGHT...SO THE AMPLE MOISTURE IN THE
ATMOSPHERE COULD RESULT IN DOWNPOURS WITH THE STORMS. DEPENDING ON
THE TRACK OF THESE STORMS...IF THE STORMS MOVE RELATIVELY SLOWLY
OR IF THERE IS TRAINING...SOME AREAS COULD SEE LOCALLY HEAVY
RAINFALL AND PONDING OF WATER. AT THIS TIME...THE FORECAST IS FOR
WIDESPREAD RAINFALL OF 0.50" TO 1.25" OVER NE MINNESOTA AND
ADJACENT AREAS OF NW WISCONSIN.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 249 PM CDT SUN JUL 5 2015

SHOWERS AND THUNDERSTORMS WILL BE ONGOING AT 12Z MONDAY MORNING
AS A COLD FRONT BISECTS THE FORECAST AREA FROM NORTHEAST TO
SOUTHWEST. MODERATE TO HEAVY RAINFALL IS EXPECTED DURING THE
MORNING HOURS AND EARLY AFTERNOON OVER NORTHWEST WISCONSIN WITH
SHOWERS AND STORMS ENDING BEFORE NOON OVER MINNESOTA. MAIN
LONGWAVE TROF WILL PUSH THROUGH REMAINDER OF MINNESOTA AND INTO
WISCONSIN BY MONDAY EVENING. BROAD SUBSIDENCE IN THE WAKE OF THE
TROUGH SHOULD RESULT IN RAPIDLY CLEARING SKIES OVER NORTH CENTRAL
MINNESOTA DURING THE DAY...SPREADING INTO WISCONSIN MONDAY
EVENING.

DRIER AND QUIETER WEATHER IS EXPECTED MONDAY NIGHT THROUGH
TUESDAY NIGHT AS A ZONAL FLOW PATTERN SETS UP OVER THE NORTHERN
CONUS. TEMPERATURES WILL TREND SLIGHTLY COOLER IN THE WAKE OF THE
LOW...WITH A GRADUAL WARMING TREND INTO WEDNESDAY.

A WEAK SHORTWAVE TROUGH AND A RIBBON OF VORTICITY WILL ROTATE
THROUGH THE ZONAL FLOW ON WEDNESDAY...PULLING A WEAK COOL FRONT
ACROSS THE NORTHERN PLAINS AND INTO MINNESOTA BY LATE WEDNESDAY
AFTERNOON. SUPPORT FOR THIS FEATURE WILL BE LIGHT AND THE BOUNDARY
IS EXPECTED TO LINE UP NEARLY PARALLEL TO THE MEAN
FLOW...RESULTING IN SLOW PROPAGATION THROUGH WEDNESDAY AFTERNOON.
SCATTERED SHOWERS OR AN ISOLATED THUNDERSTORM ARE POSSIBLE OVER
KOOCHICHING AND NORTHERN ITASCA COUNTIES DURING THE
AFTERNOON...EXTENDING EASTWARD DURING THE EVENING TO INCLUDE THE
BORDERLAND. MINOR DISCREPANCIES IN THE GUIDANCE HINT THAT AN
ISOLATED SHOWER OR STORM MAY DEVELOP FARTHER SOUTH LATE WEDNESDAY
AFTERNOON OR EARLY THURSDAY EVENING. HAVE OPTED FOR LOW-END CHANCE
POPS TO ACCOUNT FOR THIS POTENTIAL. ANOTHER ROUND OF ISOLATED PM
SHOWERS AND STORMS WILL BE POSSIBLE ON THURSDAY AFTERNOON AS THE
FRONT WASHES OUT ACROSS THE NORTH.

A PATTERN SHIFT IS SHAPING UP FOR THE LATTER WEEK AS A LONGWAVE
TROUGH DEVELOPS OVER THE WESTERN CONUS. SOUTHWESTERLY FLOW WILL
DEVELOP ACROSS THE PLAINS AND UPPER MIDWEST FRIDAY THROUGH SUNDAY.
EXPECT HIGH TEMPERATURES TO CLIMB INTO THE UPPER 70S TO LOW 80S
ACROSS THE REGION...WITH WARMER TEMPERATURES NOT ENTIRELY OUT OF
THE QUESTION. MOISTURE WILL BE INCREASING AS WELL DURING THE
PERIOD WITH STICKY DEWPOINTS IN THE 60S BUILDING THROUGH THE
WEEKEND. GFS/ECMWF/GEM ALL HINT AT A SHORTWAVE TROUGH ROTATING
THROUGH THE BASE OF THE WESTERN CONUS WAVE DURING THIS
PERIOD...AND EVENTUALLY ADVANCING TOWARD MINNESOTA. THUNDERSTORMS
WILL BE POSSIBLE ONCE AGAIN FRIDAY NIGHT THROUGH SUNDAY...SOME OF
WHICH MAY BE STRONG.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1230 PM CDT SUN JUL 5 2015

CONTINUING TO MONITOR THUNDERSTORM DEVELOPMENT OVER NW MINNESOTA
EARLY THIS AFTERNOON. MCS IS EXPECTED TO MOVE EASTWARD THROUGH NC
AND INTO NE MINNESOTA THIS AFTERNOON/EARLY EVENING. ADDITIONAL
THUNDERSTORM DEVELOPMENT IS LIKELY SOUTH OF THE THUNDERSTORM
COMPLEX. MAINTAINED GENERAL TRENDS FROM PREVIOUS FORECAST AND
REFINED STORM IMPACTS AT INL/HIB. CONFIDENCE DECREASES AT
BRD/DLH/HYR AS ADDITIONAL DEVELOPMENT WILL BE REQUIRED FOR STORMS
TO AFFECT THOSE TERMINALS. GENERALLY VFR/MVFR CIGS AND VSBYS
EXPECTED...EXCEPT WHEN THUNDERSTORMS PASS THROUGH. HAVE SEEN VSBYS
AS LOW AS 1/4 SM IN EASTERN NORTH DAKOTA THIS MORNING...AND
BELIEVE LOW VSBYS ARE LIKELY AT INL AS STORMS PASS THROUGH. HAVE
REFLECTED TIMING IN TEMPO GROUP THERE. ALSO CARRYING A PERIOD OF
IFR VSBYS AT BRD WITH RAIN AND STORMS...TRANSITIONING TO FOG/MIST
AFTER PRECIPITATION ENDS. MUCH LESS CONFIDENT IN VERY LOW VSBYS AT
REMAINING TERMINALS AND WILL UPDATE THROUGH THE AFTERNOON AS
NECESSARY. RAIN AND THUNDERSTORMS WILL END OVERNIGHT FOR ALL BUT
HYR...WHERE SHOWERS MAY LINGER THROUGH MONDAY MORNING. EXPECT A
PERIOD OF MVFR/IFR CIGS AND VSBYS OVERNIGHT FOR SITES WHICH
RECEIVE RAINFALL.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  66  71  51  69 /  80  70  10   0
INL  57  68  45  69 /  70  20  10   0
BRD  66  73  51  70 /  80  50  10   0
HYR  69  73  51  69 /  80  90  10   0
ASX  68  72  52  68 /  80  90  20   0

&&

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

$$

UPDATE...JJM
SHORT TERM...GROCHOCINSKI
LONG TERM...HUYCK
AVIATION...HUYCK


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