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000
FXUS63 KDLH 201917
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
217 PM CDT MON MAY 20 2013

.AVIATION.../18Z TAF ISSUANCE/
SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE
ACROSS THE FORECAST THIS AFTERNOON AND TONIGHT. CONDITIONS WILL
VARY FROM LARGELY FROM VFR AT KHYR...TO VLIFR AT KDLH. LOW
PRESSURE WILL CONTINUE TO ROTATE THROUGHOUT THE AREA...KEEPING
PERSISTENT LOW CLOUDS AND RAIN SHOWERS THROUGH TUESDAY.

&&

.PREV DISCUSSION... /ISSUED 1023 AM CDT MON MAY 20 2013/

UPDATE...

THE FOCUS TODAY REMAINS ON SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH THE NEARLY STACKED LOW PRESSURE SYSTEM NEAR EASTERN SOUTH
DAKOTA AND WITH ITS ASSOCIATED WARM FRONT EXTENDING INTO THE
SOUTHERN FORECAST AREA IN NW WISCONSIN. BESIDES THE HIGH CHANCES
OF SHOWERS...MAYBE A LITTLE THUNDER...ACROSS THE NORTHERN AND
WESTERN FORECAST AREA...THE LATEST HIGH RESOLUTION MODELS SUGGEST
INCREASING CHANCES OF THUNDERSTORMS ACROSS THE SOUTHERN FORECAST
AREA THIS AFTERNOON AND EARLY THIS EVENING ALONG AND NEAR THE WARM
FRONT. SOME OF THOSE STORMS COULD BE STRONG OR SEVERE. THE
GREATEST THREAT OF SEVERE STORMS IS OVER NW WISCONSIN WHERE THE
NAM12 INDICATES BETTER POTENTIAL FOR STORM ORGANIZATION. DEEP
LAYER SHEAR (0-6 KM) WILL BE ABOUT 30 TO 35 KNOTS AND CAPE COULD
APPROACH 1500 J/KG. ALSO...THERE WILL BE STRONGER FLOW ALOFT OVER
NW WISCONSIN DUE TO THE ORIENTATION OF THE JET STREAM.

THE STRONG AND GUSTY ENE WINDS COMING OFF LAKE SUPERIOR APPEAR TO
BE STRONGER THAN PREVIOUSLY FORECASTED...SO I INCREASED WINDS NEAR
LAKE SUPERIOR THROUGH TONIGHT. I ALSO ADDED PATCHY FOG ALONG THE
LAKE SHORE THROUGH TONIGHT.

PREV DISCUSSION... /ISSUED 712 AM CDT MON MAY 20 2013/

AVIATION.../12Z TAF ISSUANCE/
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE
NORTHLAND TODAY AND TONIGHT. CONDITIONS WILL VARY FROM LARGELY VFR
AT KHYR...TO VLIFR AT KDLH. LOW PRESSURE WILL CONTINUE TO ROTATE
THROUGHOUT THE AREA.

PREV DISCUSSION... /ISSUED 354 AM CDT MON MAY 20 2013/

SHORT TERM...PWS AXIS HAS SHIFTED INTO ERN WISC ZONES AND EXTENDS
NORTHWESTWARD INTO ARROWHEAD. ALONG THIS MOIST PLUME SHOWERS AND
A FEW THUNDERSTORMS CONTINUE. QUICK CHECK WITH ASHLAND CO SHERIFFS
INDICATES EARLIER FLOODING HAS SUBSIDED NEAR ASHLAND. HOWEVER
GIVEN CONTINUED RAIN MOVING ACROSS AREA NEXT SEVERAL HRS HAVE
EXTENDED AND EXPANDED SLIGHTLY THE COVERAGE OF THE FLOOD ADVISORY.
OTHERWISE...FAIRLY QUIET ACROSS MOST OF CWA EXCEPT NRN MN ZONES
WHERE 85H FRONTOGENESIS HAS WEAKENED ACCORDING TO SPC
MESOANALYSIS. VERY GUSTY WINDS OCCURRING AS A RESULT OF SFC
PRESSURE GRADIENT ENHANCED BY COLD LAKE AND APPROACHING SFC LOW.

TODAY...SFC LOW WILL MEANDER NEAR WRN MN WITH WARM FRONT
STRETCHING EAST ACROSS SRN WISC ZONES. NUMEROUS MDLS SUGGEST A
RELATIVE DRY SLOT WILL ADVECT INTO SERN CWA TODAY WITH A DECREASE
IN FREQUENCY OF RW/TRW. CONCERN IS INCREASING FOR SVRWX EVENT OVER
SRN TIER OF CWA ROUGHLY FROM SRN PINE COUNTY AND INTO NORTHWEST
WISCONSIN...SOUTH OF MARINE BOUNDARY. HI RES DLHWRF AND HRRR3KM
DIFFER ON POSITION/MOVEMENT OF SFC BNDRY DURING THE AFTERNOON. LATEST
FCST SBCAPES INCREASE TO 1500 J/KG AS BDRY LYR GETS AN OPPORTUNITY
TO WARM IN ABSENCE OF PERSISTENT RAIN. SFC BDRY WILL PROVIDE LOW
LEVEL HELICITY FOR ANY DEVELOPING CONVECTION BY AFTN. MAIN
LIMITING FACTOR APPEARS TO BE DEEP LAYER BULK SHEAR WHICH IS ON
THE LOW END OF THE SPECTRUM REQUIRED FOR STORM ORGANIZATION. WILL
CARRY FLOOD WATCH FOR NOW ALTHOUGH IT APPEARS THAT AMOUNTS HAVE
BEEN LOW ENOUGH IN MANY AREAS TO LIMIT FLOOD THREAT. STILL HAVE
85H MOIST AXIS SHIFTING AND ROTATING NORTH INTO NRN MN CWA TONIGHT.

TONIGHT/TOMORROW...SFC/MID LVL LOW SHIFTS SLOWLY SOUTH AS WARM
CONVEYOR BELT EVENTUALLY WORKS ITS WAY INTO NRN PERIPHERY
OF SYNOPTIC SCALE CIRCULATION. MDLS SUGGEST THAT AREA OF
85H FRONTOGENESIS WILL REMAIN QUITE HEALTH ACROSS NRN TIER OF MN
ZONES AND THIS MAY BE ULTIMATELY WHERE HIGHEST TOTALS OCCUR. ANY
LIMITED SVRWX THREAT WILL BE SUPPRESSED FARTHER SOUTH OF CWA WITH
TIME.

LONG TERM...TUESDAY NIGHT THROUGH MONDAY.

THE LARGE LOW PRESSURE SYSTEM WILL CONTINUE TO AFFECT THE NORTHLAND
INTO THE MIDDLE OF THE WORK WEEK...WITH SHOWERS AND A FEW
THUNDERSTORMS LIKELY TUESDAY NIGHT AND INTO WEDNESDAY. BY
WEDNESDAY...THE CHANCE OF PRECIPITATION WILL DECREASE DRAMATICALLY
ACROSS THE NORTH...WHILE IT WILL DECREASE ACROSS THE SOUTH WEDNESDAY
NIGHT. DRY HIGH PRESSURE WILL BE IN FULL FORCE ACROSS THE NORTHLAND
BY THURSDAY...ALLOWING FOR A PERIOD OF DRYING ACROSS THE REGION. THE
NEXT CHANCE OF PRECIPITATION WILL ARRIVE SATURDAY NIGHT AND CONTINUE
INTO THE WEEKEND. NOT LOOKING FOR MUCH PRECIPITATION WITH THE NEXT
SYSTEM...SO WILL BE GOING WITH CHANCE POPS AT THIS POINT. IT LOOKS
LIKE A BIT MORE SUBSTANTIAL PRECIPITATION VERY LATE IN THE
PERIOD...WITH A STRONG LOW PRESSURE SYSTEM MOVING THROUGH THE PLAINS
BY MONDAY. TEMPERATURES WILL LARGELY BE IN THE 60S THROUGHOUT THE
ENTIRE EXTENDED PERIOD. THE EXCEPTIONS WILL BE NEAR LAKE
SUPERIOR...WHERE TEMPERATURES WILL LIKELY BE MUCH COOLER.

&&

.POINT TEMPS/POPS...
DLH  44  52  41  53 /  70  70  70  60
INL  45  56  43  66 /  70  60  40  30
BRD  52  62  47  58 /  70  70  60  60
HYR  54  68  45  58 /  70  70  60  60
ASX  46  54  41  51 /  70  70  60  70

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR MNZ010>012-018>021-
     025-026-033>038.

WI...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR WIZ001>004-006>009.

LS...SMALL CRAFT ADVISORY UNTIL 11 AM CDT WEDNESDAY FOR LSZ121-148.

     SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 11 AM CDT WEDNESDAY
     FOR LSZ140>147.

     GALE WARNING UNTIL 4 AM CDT TUESDAY FOR LSZ140>147.

&&

$$

AVIATION...GRANING