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000
FXUS63 KDLH 181434 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
934 AM CDT SAT MAY 18 2013

.UPDATE...
MCV GENERATED BY OVERNIGHT CONVECTION IN THE DAKOTAS IS MOVING
INTO THE BRAINERD/WALKER AREAS AS OF MID-MORNING. OUTFLOW FROM
LARGE CONVECTIVE COMPLEX FROM NEAR MSP METRO AREA TO IRONWOOD HAS
TEMPORARILY SHUNTED THE SURFACE WARM SECTOR WELL SOUTH OF THE
DULUTH CWA.

MCV WILL CONTINUE NEWD INTO MID AFTERNOON..AND LOCAL MESOSCALE
LIFT IS LIKELY TO CONTINUE TO SUPPORT SHOWERS AND A FEW TSTORMS
OVER NRN MN FOR MUCH OF THE DAY AS ASCENT AHEAD OF THIS FEATURE
INTERACTS WITH WEAKLY UNSTABLE AIRMASS. AS THE NOCTURNAL LOW LEVEL
JET GOES THROUGH ITS DIURNAL WEAKENING/BACKING CYCLE LATE THIS
MORNING..CONVECTION NEAR MSP SHOULD GRADUALLY WEAKEN..AIDED BY
LARGE SCALE SUBSIDENCE IN WAKE OF PASSING MCV. THIS SHOULD LEAVE
MUCH OF OUR SOUTHERN CWA WITH ONLY LOW CHANCES FOR POPS FOR MUCH
OF THIS AFTERNOON. HOWEVER..STAGE APPEARS TO BE SET FOR ANOTHER
ROUND OF SHOWERS/TSTORMS TONIGHT.

WANING OF CONVECTIVE ACTIVITY SHOULD ALLOW SURFACE-925 MB WARM
FRONTAL ZONE TO RE-CONSOLIDATE SOMEWHERE NEAR THE I94 CORRIDOR BY
MID TO LATE AFTERNOON..WITH A FAIRLY ROBUST WARM SECTOR TO THE
SOUTH OF THE FRONT AS SURFACE DEWPOINTS WELL INTO THE 60S STREAM
NORTHWARD FROM THE CENTRAL PLAINS. LOW LEVEL JET WILL REFORM THIS
EVENING..AND ENHANCED LIFT DRIVEN BY WARM/MOIST ADVECTION AND LOW
LEVEL FGEN ALONG THE BAROCLINIC ZONE SHOULD SUPPORT ADDITIONAL
TSTORMS OVERNIGHT. WHILE THE BEST CHANCE OF ANY SVR STORMS IS
EXPECTED TO REMAIN CONFINED TO AREAS WELL SOUTHWEST OF THE DLH
CWA..WE CERTAINLY NOT RULE OUT A FEW STRONG OR MARGINALLY SEVERE
STORMS OVER THE SW CWA OVERNIGHT.

HOWEVER..THE MAIN POINT OF FOCUS FOR THE NORTHLAND WILL BE HEAVY
RAINFALL POTENTIAL. SOME AREAS OF NW WISCONSIN ALREADY HAVE
RECEIVED BETWEEN 2 AND 4 INCHES OF RAIN WITH THE INITIAL ROUND
OVERNIGHT..AND ONE REPOT OF 2+ INCHES WAS ALSO RECEIVED FROM
SOUTHERN CASS COUNTY. CONFIDENT IS NOT QUITE HIGH ENOUGH JUST
YET DUE TO UNCERTAINTY OF EXACT PLACEMENT AND INTENSITY OF
CONVECTION TONITE..BUT WE MAY NEED TO HOIST A FLASH FLOOD WATCH
FOR SOME AREAS TONIGHT/SUNDAY MORNING.

FINALLY..BROAD EASTERLY GRADIENT ALONG WITH CLOUDS AND PRECIP
SHOULD MAKE FOR ANOTHER COLD DAY IN AREAS EXPOSED TO LK SUPERIOR
WHERE COLD/STABLE MARINE LAYER SHOULD BE ABLE TO REMAIN LOCKED IN
PLACE FOR MOST OF THE DAY. UPDATES TO GRIDS AND ASSOCIATED TEXT
PRODUCTS REFLECTING ABOVE MENTIONED REASONING AND LATEST
OBSERVATIONAL TRENDS ARE ALREADY AVAILABLE.

&&

.PREV DISCUSSION... /ISSUED 712 AM CDT SAT MAY 18 2013/

AVIATION.../12Z TAF ISSUANCE/
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE FOUND
ACROSS THE NORTHLAND TODAY AND TONIGHT. EAST WINDS WILL MAINTAIN
LOW CLOUDS AND FOG AS WELL NORTH OF A WARM FRONT TO THE SOUTH OF
OUR AREA. TAF SITES WILL VARY CONSIDERABLY BETWEEN VFR AND
IFR/LIFR.

PREV DISCUSSION... /ISSUED 346 AM CDT SAT MAY 18 2013/

.LOCALLY HEAVY RAIN FOR PARTS OF THE NORTHLAND...

SHORT TERM...SHOWERS/STORMS ARE MOVING NORTHEAST ACROSS THE
SOUTHERN CWA EARLY THIS MORNING. AN AREA OF WEAK FRONTOGENESIS AT
985H IS DRAPED OVER THE SWRN CWA WITH THE MOIST AXIS AT 85H
STRETCHING FROM NWRN MN INTO THE BRD LAKES REGION. PRECIP IS
REGENERATING WEST OF THE CWA AND MOVING NE TOWARDS THE BRD LAKES
VICINITY. 3 TO 4 TENTHS INCH RAINFALL HAS OCCURED IN PARTS OF
CASS COUNTY SO FAR WITH AMOUNTS TAPERING TO ALMOST A TENTH AT
KDLH.

TODAY...VERY TRICKY PATTERN AS SYNOPTIC SCALE AMPLIFIES ACROSS
WRN/CTRL CONUS THIS PERIOD. LOW LVL BOUNDARIES AND THEIR FORECAST
POSITIONING ULTIMATELY DRIVE MORE FAVORED AREA OF POPS. HOWEVER
THESE BOUNDARIES ARE INFLUENCED BY THE VERY CONVECTION THEY
GENERATE...IMPEDING NORTHWARD PROGRESS. CWA REMAINS UNDER A LARGE
SCALE WARM ADVECTION REGIME WHICH ALLOWS PWATS TO INCREASE AND
SHOWERS /STORMS TO OCCUR ALMOST ANYTIME. GENERAL FEELING IS THAT
DEEP LAYER MOISTURE WILL SPREAD NORTHWARD ACROSS THE REGION TODAY
WITH PERIODS OF SHOWERS AND STORMS EXPECTED. HI RES DLHWRF/ECMWF
MDLS SUGGEST LOW LVL THERMAL BDRY REMAINS IN MORE CLASSIC LOCATION
ACROSS CTRL WISC ZONES WEST TO CASS LAKE MN BY 00Z SUNDAY. FCST
INSTABILITY SHOWS AN AXIS OF HIGHER SFC CAPE DEVELOPING NEAR
MARINE BDRY THIS AFTN IN WISCONSIN. COULD SEE CONVECTION INCREASE
AT THAT TIME HOWEVER CONFIDENCE IS LOWERED BY DIFFERENCES AMONGST
FCST SNDGS WITHIN THE MDL SUITE. A SLIGHT RISK OF SVR STORMS PER
SPC ACROSS SWRN CORNER OF CWA INCLUDING KBRD TO BACKUS CORRIDOR.

OVERNIGHT/SUNDAY...THE MAIN CORRIDOR OF PRECIP/CONVECTION SHOULD SETUP
OVER NWRN CWA AND SOUTH TO WRN MN. THIS IS ALONG THE WELL
DEVELOPED INVERTED TROUGH IN THE BDRY LYR. THIS FEATURE WILL VERY
SLOWLY SHIFT SOUTHEAST SUNDAY. AS THAT OCCURS...EXPECT AN INCREASE
IN LOW LVL NE FLOW OVER LAKE SUPERIOR. HEAVIER RAIN SHOULD SHIFT
EASTWARD ACROSS THE CWA SUNDAY AFTERNOON. AREAL AVERAGE QPF MAY
REACH 1 TO 2 INCHES OVER A LARGE PART OF MN CWA...WITH ISOLATED
HIGHER TOTALS IN REPEAT CONVECTION ZONES.

LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.

THE ACTIVE WEATHER PATTERN WILL CONTINUE FOR MUCH OF THE FIRST PART
OF THE EXTENDED PERIOD...AS LOW PRESSURE ESSENTIALLY CLOSES OFF OVER
MINNESOTA BY TUESDAY AFTERNOON. AS IS FAIRLY TYPICAL FOR MID MAY...A
PROLONGED PERIOD OF SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE
STORM SYSTEM. THERE LOOKS TO BE SEVERAL ROUNDS OF PRECIPITATION
WHICH MAY RESULT IN SEVERAL INCHES OF RAIN FOR MANY LOCATIONS
THROUGHOUT THE DURATION OF THE STORM SYSTEM. WILL MAINTAIN HIGH POPS
FOR SUNDAY NIGHT THROUGH ABOUT WEDNESDAY...AND THEN GRADUALLY START
TO DECREASE POPS. THE MODELS ARE COMING INTO A BIT BETTER AGREEMENT
BUT THERE ARE DEFINITELY DISTINCT DIFFERENCES CONCERNING OVERALL QPF
AND TIMING. DRY HIGH PRESSURE WILL BUILD IN BEHIND THE
SYSTEM...BRINGING VERY DRY AIR INTO THE REGION FOR MUCH OF
THURSDAY...FRIDAY AND SATURDAY. TEMPS WILL LARGELY BE IN THE 60S FOR
DAYTIME HIGHS WITH LITTLE EXCEPTION. AREAS NEAR LAKE SUPERIOR WILL
BE COOLER WITH PERSISTENT EAST WINDS PREVAILING.

AVIATION...06Z TAFS.
THUNDERSTORMS HAVE DEVELOPED/SPREAD INTO THE BRD AREA WITH MORE
SHOWERS MOVING THROUGH EAST CENTRAL MN AND INTO NW WI. EXPECT MORE
SHOWERS TO DEVELOP AND AFFECT ALL TERMINALS EXCEPT INL THROUGH THE
EARLY MORNING. BY MID MORNING...ADDITIONAL STORMS ARE EXPECTED TO
AFFECT MOST SITES WITH INL NOT IMPACTED UNTIL 21Z. A BREAK IN THE
PCPN AFTER 21Z AT THE OTHER SITES UNTIL THE NEXT ROUND AFFECTS THE
TERMINALS ABOUT 03Z.

&&

.POINT TEMPS/POPS...
DLH  59  53  68  52 /  80  50  70  80
INL  64  53  64  53 /  70  80  80  80
BRD  77  61  77  58 /  70  80  80  70
HYR  75  58  78  61 /  80  30  70  70
ASX  65  54  74  53 /  90  30  70  80

&&

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

$$

SHORT TERM...MILLER
LONG TERM....MELDE