Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 210541 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1241 AM CDT MON JUL 21 2014

.UPDATE...
ISSUED AT 648 PM CDT SUN JUL 20 2014

AS OF 2345Z AREA RADARS REVEAL LITTLE OCCURRING ACROSS NORTHERN
MINNESOTA. A FEW SHOWERS AND A THUNDERSTORM HAVE OCCURRED FROM
KOOCHICHING COUNTY SOUTHWEST TOWARD MAHNOMEN/FOSSTON THIS EVENING. THESE
SHOWERS WERE OCCURRING ALONG/JUST AHEAD OF THE LOW LEVEL BOUNDARY
IN AN AREA OF RICH LOW LEVEL MOISTURE. SURFACE DEWPOINTS WERE IN
THE LOWER SEVENTIES IN THAT AREA AND MLCAPE VALUES WERE
2000-3500J/KG PER THE 23Z SPC MESOANALYSIS. MUCH OF THE HIGH RES
GUIDANCE SUGGESTS STORM COVERAGE WILL BE LIMITED FOR A COUPLE MORE
HOURS...THEN AN INCREASE WILL OCCUR BETWEEN 2Z-4Z. FORCING JUST IS
NOT STRONG ENOUGH AT THIS TIME. THERE IS A SUBTLE WAVE MOVING
THROUGH THE SOUTHEAST MB/NORTHWEST OT AREA THAT MAY ADD ENOUGH
LIFT TO GET DEEPER CONVECTION GOING. ONCE DEEPER CONVECTION
DEVELOPS...SHEAR/CAPE ARE SUPPORTIVE FOR SEVERE STORMS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 320 PM CDT SUN JUL 20 2014

THROUGH THIS EVENING...WARM AND HUMID CONDITIONS HAVE DEVELOPED
OVER MUCH OF THE NORTHLAND THIS AFTERNOON DUE TO GUSTY SOUTHERLY
WINDS AHEAD OF AN APPROACHING TROUGH OF LOW PRESSURE IN THE
NORTHERN PLAINS. THIS TROUGH WILL BRING INCREASING CHANCES OF
SHOWERS AND THUNDERSTORMS FROM THE WEST LATE THIS AFTERNOON AND
THIS EVENING. THERE IS A SLIGHT RISK THAT THESE STORMS COULD
BECOME SEVERE AND PRODUCE GUSTY WINDS...HAIL...AND HEAVY RAIN. THE
MODELS ARE IN DECENT AGREEMENT THAT SCATTERED TO ISOLATED STORMS
WILL DEVELOP IN THE NW AND W FORECAST AREA LATE THIS
AFTERNOON...AND THEN MOVE EAST THROUGH THE EVENING. MIXED LAYER
CAPE WILL LIKELY REACH THE 1500 TO 3000 J/KG RANGE...DEEP LAYER (0
TO 6 KM) WIND SHEAR BETWEEN 35 AND 40 KNOTS...SURFACE DEW POINTS
IN THE LOW 70S...AND PRECIPITABLE WATER VALUES BETWEEN 1.5 AND
1.75 INCHES. THE MID LEVEL CAP HAS BEEN STEADILY ERODING THROUGH
THE AFTERNOON.

LATER TONIGHT...THE THREAT FOR SHOWERS AND STORMS WILL LIKELY
SHIFT EAST THROUGH THE REST OF THE NIGHT AS THE AXIS OF LOW/MID
LEVEL MOISTURE TRANSPORT SHIFTS EAST. THE TROUGH WILL STALL AND
SET UP A STATIONARY/WARM FRONT DRAPED ACROSS THE NORTHERN FORECAST
AREA. THE HIGH DEW POINT TEMPERATURES WILL CAUSE VERY WARM
OVERNIGHT LOW TEMPERATURES. THE DAILY RECORDS FOR HIGHEST MINIMUM
TEMPERATURES FOR MONDAY COULD BE BROKEN AT BOTH DULUTH AND
INTERNATIONAL FALLS...WITH THE RECORDS FOR JULY 21ST BEING 68
DEGREES AT BOTH LOCATIONS. THE HIGH HUMIDITY...LIGHT WINDS...AND
MOISTURE FROM THE RAIN EARLIER IN THE NIGHT COULD CAUSE FOG TO
FORM OVER PARTS OF THE NORTHLAND.

MONDAY...THE WARM AND SOUTHERLY FLOW WILL CONTINUE OVER THE
NORTHLAND. THE STATIONARY/WARM FRONT WILL CONTINUE TO BE DRAPED
FROM WEST TO EAST OVER OR NEAR FAR NORTHERN MINNESOTA.
TEMPERATURES WILL LIKELY CLIMB TO THE UPPER 80S AND LOW 90S OVER
MUCH OF THE FORECAST AREA. THE COMBINATION OF THE HEAT AND
HUMIDITY...WITH DEW POINT TEMPERATURES IN THE LOW TO MIDDLE
70S...WILL CAUSE HEAT INDICES TO APPROACH OR REACH AROUND 100
DEGREES. THERE WILL BE INCREASING CHANCES OF SHOWERS AND STORMS
OVER NE MINNESOTA DURING THE AFTERNOON...PRIMARILY THE LATE
AFTERNOON. I KEPT THE CHANCES NORTH OF THE TWIN PORTS...CLOSER TO
THE FRONT...BECAUSE THE WARM MID LEVEL TEMPERATURES WILL LIKELY
KEEP THE SOUTHERN AND SE FORECAST AREA CAPPED.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 PM CDT SUN JUL 20 2014

A VERY WARM AIRMASS WITH ABUNDANT MOISTURE WILL SET THE STAGE FOR
WIDESPREAD HEAVY RAIN AND SEVERE STORMS MONDAY NIGHT THROUGH
TUESDAY MORNING.

FOCUS IS ON A STRENGTHENING BAROCLINIC ZONE/WARM FRONT THAT
BECOMES POSITIONED OVER NW MINNESOTA MONDAY AFTERNOON. A SHORT
WAVE WITH H85 CLOSED LOW...WILL TRANSLATE ALONG THIS BOUNDARY
THROUGH THE NIGHT...TRIGGERING STORMS WITH HEAVY RAIN ACROSS MUCH
OF THE REGION INTO TUESDAY. EXCESSIVE INSTABILITY (>3000 J/KG
CAPE) AND EXTREME PWAT VALUES (APPROACHING 2" OR 99TH PERCENTILE
OF NORMAL)...ALONG WITH A COUPLED JET AND LARGE OMEGA
VALUES...WILL ALL CONTRIBUTE TOWARDS A POTENTIAL FOR SEVERE
WEATHER OUTBREAK MONDAY EVENING/OVERNIGHT.

THE GREATEST THREAT FOR SEVERE STORMS MONDAY EVENING IS FOCUSED
OVER THE BRAINERD LAKES AREAS...EAST THROUGH THE ST CROIX RIVER
VALLEY...AND INTO THE HAYWARD LAKES REGION WHERE THE DEEP SHEAR
LOOKS TO BE MOST FAVORABLE.

ALTHOUGH THERE REMAINS MINOR DIFFERENCES IN TIMING...THE LATEST
NAM/GFS/ECM ARE ALL IN AGREEMENT THAT THE SFC REFLECTION TROUGH
THAT ORGANIZES ALONG THE BORDERLAND MONDAY AFTERNOON...SAGS SOUTH
OVER THE NRN HALF OF MINNESOTA THROUGH MIDNIGHT...THEN PUSHES EAST
OVER WESTERN LAKE SUPERIOR/NORTHERN WIS MID-DAY TUESDAY. AT THIS
TIME...THE ONSET OF THE HEAVY RAIN/SEVERE THREAT ARRIVES FOR
LOCATIONS IN NORTH CENTRAL TO NORTHEAST MINN MONDAY EVENING (5-7
PM TIME FRAME)...REACHING THE NRN WIS ZONES DURING THE EARLY
MORNING HOURS.

HAVE INCREASED POPS TO WIDESPREAD DEFINITE SHRA/TSTMS WITH HEAVY
RAIN WORDING MONDAY NIGHT. LATEST WIDESPREAD RAINFALL AMOUNTS
AROUND AN INCH ARE LIKELY...WITH AREAS THE RECEIVE THE STRONGER
STORMS HAVING THE POTENTIAL FOR AMOUNTS IN EXCESS OF 3 INCHES.

DRY CONDITIONS WITH COOLER TEMPERATURES AND MUCH LOWER HUMIDITY
WILL MAKE A RETURN TUESDAY NIGHT THROUGH THURSDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1238 AM CDT MON JUL 21 2014

A LOW LEVEL BOUNDARY STRETCHED FROM NEAR FLAG ISLAND SOUTHWEST INTO
SOUTHERN NORTH DAKOTA EARLY THIS MORNIGN. A VERY MOIST AIRMASS
COVERED THE REGION AHEAD OF THIS BOUNDARY. A FEW THUNDERSTORMS WILL
REMAIN POSSIBLE TONIGHT...HIGHEST CHANCE OVER FAR NORTHERN
MINNESOTA. THE LOW LEVEL BOUNDARY WILL NOT MOVE MUCH TONIGHT...BUT
WILL MAKE SOME EASTWARD PROGRESS OVER THE BORDER REGION. MODEL
GUIDANCE SUGGESTS THE SHOWERS/STORMS WILL DIMINISH AFTER ABOUT
07Z...BUT WE EXPECT SOME ISOLATED STORMS TO REMAIN POSSIBLE
OVERNIGHT.

THERE REMAINED QUITE A BIT OF CLOUDS FROM 3500-5000FT...AND WE
EXPECT THAT TO SLOWLY DIMINISH OVER WESTERN AREAS. HOWEVER...FOG AND
SOME IFR CEILINGS WILL AGAIN BE POSSIBLE EARLY THIS MORNING.

STRONGER LIFT WILL IMPACT THE REGION MONDAY AND MONDAY
NIGHT...CAUSING SHOWERS/STORMS TO INCREASE IN COVERAGE...ESPECIALLY
MONDAY NIGHT. WIDESPREAD STORMS ARE LIKELY AND SOME COULD BE
SEVERE IN THE AFTERNOON/OVERNIGHT PERIOD. WE HAVE THE HIGHEST CHANCE
FOR STORMS IN THE TAFS TONIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  67  67  49  71 /  90  70   0   0
INL  59  76  50  75 /  80  40   0   0
BRD  71  76  55  78 /  90  40   0   0
HYR  72  80  53  75 /  90  80  10   0
ASX  70  71  51  69 /  90  80  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT THIS EVENING
     FOR MNZ019-025-026-033>038.

WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT THIS EVENING
     FOR WIZ001>003-006>008.

LS...NONE.
&&

$$

UPDATE...MELDE
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...CLC






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