000
FXUS63 KDLH 191219
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
719 AM CDT SUN MAY 19 2013

.AVIATION.../12Z TAF ISSUANCE/

WIDESPREAD IFR TO VLIFR CONDITIONS WILL BE FOUND ACROSS THE TAF
SITES EARLY TODAY...BUT CONDITIONS WILL LARGELY IMPROVE TO MVFR OR
IFR DURING THE MORNING. SOME DENSE FOG WILL LINGER...ESPECIALLY
NEAR LAKE SUPERIOR. SHOWERS AND THUNDERSTORMS WILL CONTINUE OFF
AND ON THROUGHOUT THE PERIOD.

&&

.PREV DISCUSSION... /ISSUED 401 AM CDT SUN MAY 19 2013/

..FLASH FLOOD WATCH ISSUED FOR NORTHEAST MINNESOTA THROUGH MONDAY...

SHORT TERM...AREA OF 85H FRONTOGENESIS ACROSS NR MN CWA
CONTINUES TO PRODUCE SCTD CONVECTION ALTHOUGH AREAL COVERAGE HAS
DECREASED OVER LAST FEW HRS. MEANWHILE LARGE AREA OF RAIN AND
THUNDERSTORMS STRETCHES FROM SERN NODAK INTO SWRN MN/NWRN IOWA.
THIS IS ASSOCIATED WITH PWS AXIS AND EJECTING MID LVL SHORTWAVE
TROF. DENSE FOG STILL LINGERS NEAR LAKE SUPERIOR AND SHOULD
CONTINUE INTO MID MORNING...IF NOT LONGER.

TODAY/TONIGHT/TOMORROW...ANOMALOUS UPPER TROF OVER CTRL CONUS WILL
CONTINUE TO ADVECT PWATS IN EXCESS OF 1.5 INCHES INTO THE REGION
NEXT 48 HRS. MAIN FOCUS AT LOW LEVELS WILL BE INVERTED TROUGH
ORIGINATING FROM SFC LOW ACROSS ERN SODAK INTO NWRN MN THIS AFTN.
HAVE EXPANDED THE FFA TO INCLUDE ALL MN ZONES THROUGH MONDAY. VERY
SLOW MOVING NATURE OF SFC/MID LVL LOW...VERY HIGH PWS..AND DEEP
CYCLONIC NATURE OF UPPER FLOW WILL ENSURE A PROLONGED PERIOD OF
WET WEATHER ACROSS THE CWA. DIFFICULT TO ASCERTAIN TIMING OF
PRECIPITATION AREAS BUT WITH WARM CLOUD DEPTHS NEAR/ABOVE 3KM ANY
CONVECTION WILL HAVE ACCESS TO VERY WET PROFILES INTO MONDAY.
CONFIDENCE IS LOW/MEDIUM ON FLOOD POTENTIAL. FFG VALUES ARE
STARTING LOWEST OVER SWRN CWA HOWEVER REMAINDER OF CWA COULD
EXPERIENCE ISSUES WITH TIME DUE TO PROLONGED NATURE OF QPF
POTENTIAL. AT LOW LVLS...SFC HIGH OVER CANADA WILL SUPPLY
INCREASINGLY STRONG LOW LVL EAST/NORTHEAST FLOW INTO MN THIS
EVENING INTO MONDAY. ALTHOUGH LOW LEVEL DRY AIR WILL TRY TO MAKE
ITS AWAY INTO NERN MN...CURRENT IDEA IS THAT ANY COLD DOME
ESTABLISHED FROM LAKE WILL BE TOPPED BY ADVECTION OF WARM AND
SOMEWHAT UNSTABLE AIR ALOFT. MAY NEED TO EXTEND FFA INTO WISC
ZONES WITH AFTERNOON FORECAST UPDATES.

LONG TERM...MONDAY NIGHT THROUGH SUNDAY.

THE MASSIVE CLOSED LOW PRESSURE SYSTEM THAT WILL COVER MUCH OF THE
CENTRAL UNITED STATES EARLY IN THE PERIOD WILL CONTINUE TO AFFECT
THE WEATHER ACROSS THE NORTHLAND FOR THE FIRST PART OF THE EXTENDED.
THE CLOSED LOW WILL BE IN SOUTH DAKOTA MONDAY NIGHT...AND MOVE
TOWARD THE IOWA/MN/SD BORDER BY 00Z WED. THE LOW WILL BEGIN TO OPEN
UP AFTER THAT...MOVING INTO SOUTHERN WISCONSIN BY 00Z THURSDAY.
SHOWERS AND THUNDERSTORMS WILL BE LIKELY FOR MUCH OF THE REGION
MONDAY NIGHT INTO WEDNESDAY...AND THEN THE SHOWERS AND THUNDERSTORMS
WILL BEGIN TO SAG TO THE SOUTH AND EAST. DRY HIGH PRESSURE WILL DRY
OUT THE NORTH ON WEDNESDAY AND WEDNESDAY NIGHT...AND ESPECIALLY ON
THURSDAY. THURSDAY THROUGH FRIDAY NIGHT SHOULD GENERALLY BE DRY AND
QUIET ACROSS THE NORTHLAND...AS HIGH PRESSURE BUILDS IN. THE NEXT
BATCH OF PRECIPITATION WILL BE POSSIBLE SATURDAY INTO SUNDAY...
ALTHOUGH THE MODELS ARE SHOWING SOME DECENT TIMING ISSUES AND
DIFFERENCES IN SURFACE LOW AND UPPER LEVEL PATTERNS. TEMPERATURES
THROUGHOUT THE EXTENDED SHOULD LARGELY BE IN THE 60S...WITH SOME
SPOTTY 70S AT TIMES...AND 40S AND 50S AT TIMES NEAR THE LAKE.

UPDATE...RETRANSMITTED NEW ZFP AFTER UPDATE OF GRIDS. POPS
MINIMAL THROUGH 12Z. TWO AREAS OF PRECIP WILL BE ACROSS NRN MN CWA
IN AREA OF 85H FRONTOGENESIS...AND OVER SWRN CORNER CLOSER TO AREA
OF INSTABILITY AND APPROACHING MCS. FFA STILL IN PLACE FOR
PROSPECT OF ANOTHER DOSE OF RAIN BETWEEN 12Z-18Z.

&&

.POINT TEMPS/POPS...
DLH  58  49  52  43 /  80  80  80  70
INL  62  51  56  45 /  80  70  70  70
BRD  73  54  65  49 /  80  80  80  70
HYR  79  60  72  52 /  70  70  80  70
ASX  58  51  58  45 /  80  80  80  70

&&

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

     DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ020-021-
     037.

WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ001.

LS...SMALL CRAFT ADVISORY UNTIL 5 AM CDT TUESDAY FOR LSZ121-140>148.

&&

$$

SHORT TERM...DAP
AVIATION...DAP