000
FXUS63 KDLH 211513
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1013 AM CDT TUE MAY 21 2013

.UPDATE...

THE FOCUS FOR THIS MORNING UPDATE WAS THE THREAT OF ADDITIONAL
RAINFALL FROM RAIN SHOWERS ACROSS THE NORTHLAND TODAY. I ALLOWED
THE FLASH FLOOD WATCH EXPIRE NATURALLY AT 10 AM SINCE IT APPEARS
ANY ADDITIONAL RAINFALL SHOULD NOT POSE ANY SIGNIFICANT RISK OF
FLASH FLOODING. THE RAINFALL THAT MOVED THROUGH NORTHWEST
WISCONSIN THIS MORNING FELL ON SOME AREAS THAT HAVE HAD QUITE A
BIT OF RAINFALL OVER THE PAST SEVERAL DAYS...SO I ISSUED A NEW
AREAL FLOOD ADVISORY FOR BAYFIELD...ASHLAND...AND IRON COUNTIES
DUE TO RISING STREAMS AND SMALL RIVERS...AND STANDING WATER ON
SOME ROADS. HOWEVER...NOW THAT THE RAIN SHOWERS ARE PIVOTING INTO
NORTHEAST MINNESOTA...THE AREA THAT THE RAIN IS MOVING INTO HAS
NOT HAD A LOT OF RAIN THE PAST FEW DAYS. WHILE SOME AREAS AROUND
AND NORTH OF THE TWIN PORTS HAVE GOTTEN UP TO AN INCH OF RAIN THE
PAST FEW DAYS...THOSE AREAS SHOULD BE ABLE TO TAKE THE ADDITIONAL
HALF TO 1 INCH OF RAIN THE CURRENT RAIN SHOWERS WILL BRING
WITHOUT ANY SIGNIFICANT RISK OF FLOODING.

THE FORECAST WAS UPDATED THROUGH THIS EVENING. I GAVE THE FAR SE
FORECAST AREA NEAR PHILLIPS IN NW WISCONSIN A SLIGHT CHANCE OF
THUNDERSTORMS TODAY DUE TO THE PROXIMITY OF THE WARM FRONT.
ALSO...I LOWERED HIGH TEMPERATURES FOR TODAY WITH A THE LATEST
BLEND OF THE MODELS AND MOS GUIDANCE.

&&

.PREV DISCUSSION... /ISSUED 709 AM CDT TUE MAY 21 2013/

AVIATION.../12Z TAF ISSUANCE/
WIDESPREAD IFR OR LOWER CONDITIONS ARE IN STORE FOR THE NORTHLAND
ONCE AGAIN TODAY. CONDITIONS WILL BE BRIEFLY LIFR/VLIFR AT TIMES
AS WELL DUE TO RAIN/DRIZZLE AND LOW CLOUDS AND FOG. DRY HUDSON BAY
ORIGIN HIGH PRESSURE WILL BEGIN TO PUSH INTO THE REGION LATE IN
THE TAF PERIOD...MAINLY AFFECTING KINL WITH DRAMATICALLY IMPROVING
CONDITIONS. CLOUDS SHOULD BREAK UP TO REVEAL VFR CONDITIONS DURING
THE LATTER PART OF THE NIGHT.

PREV DISCUSSION... /ISSUED 401 AM CDT TUE MAY 21 2013/

SHORT TERM...CWA REMAINS UNDER LARGE ANOMALOUS CIRCULATION THAT HAS
BEEN TRAPPED OVER CTRL CONUS LAST FEW DAYS. ANOTHER BAND OF RAIN
IS ROTATING AROUND THE SYSTEM AND PUSHING INTO THE SRN CWA. WILL
LET FFA CONTINUE THROUGH MORNING ALTHOUGH BIGGEST THREAT APPEARS
TO BE ACROSS SRN CWA WHERE MAIN FORCING SHOULD OCCUR.

TODAY...AREA OF RAIN/THUNDER CURRENTLY OVER SRN CWA IS ALIGNED WITH
SHARPENING 85H THETAE AXIS AS IT WRAPS INTO MID LVL LOW. THIS
FEATURE IS FCST TO STRETCH EAST TO WEST ACROSS SRN CWA TODAY.
LIMITED CONVECTIVE POTENTIAL AS CLOUD CANOPY AND DEEPLY SATURATED
COLUMN MAKE FOR SOME LOW CAPE VALUES SFC/ALOFT. MOST FAVORABLE
COMBO OF INSTABILITY/SUFFICIENT DEEP LAYER SHEAR IS OVER SERN WISC
ZONES IN THE AFTN. AREA OF FRONTOGENESIS THAT HAS BEEN FAIRLY
PERSISTENT OVER NRN MN ZONES IS FCST TO WEAKEN SO HAVE TAPERED POPS
THROUGH THE AFTN HRS. ANOTHER CHILLY DAY NEAR LAKE SUPERIOR AS
STRONG ONSHORE FLOW/CLOUDS/PRECIP LIMITS TEMP RISE.

TONIGHT...DEEP LAYER DRYING SHOULD BEGIN TO PUSH FARTHER SOUTH INTO
MN ZONES. BEST THERMODYNAMICS...85H THETAE AXIS...SHIFTS SOUTH OF
REGION BY 12Z. BRD LAKES REGION MAY REMAIN UNDERNEATH MID LVL
CYCLONIC CIRCULATION AND COLLAPSING LOW LVL THETAE RIDGE LONG
ENOUGH TO KEEP QPF A BIT HIGHER THAN REMAINDER OF CWA.

TOMORROW...MID LVL LOW SLIDES SOUTHEAST OF CWA AND RIDGING BUILDS
ALOFT. SFC HIGH INCREASES AND PWATS DROP CONSIDERABLY DURING THE
DAY. SHOULD BE ENOUGH SUNSHINE TO MAKE NWRN PART OF CWA THE WARMEST
WITH LOWEST READINGS OCCURRING IN SERN CWA.

LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY.

THE MASSIVE LOW PRESSURE SYSTEM THAT HAS AFFECTED THE REGION THE
PAST SEVERAL DAYS WILL FINALLY PULL OUT OF THE NORTHLAND COMPLETELY
WEDNESDAY NIGHT...AS DRY HIGH PRESSURE BUILDS IN FROM THE NORTH. ON
THURSDAY WE COULD SEE VERY LOW RELATIVE HUMIDITY VALUES...AFTER
SEEING HIGH RELATIVE HUMIDITY FOR QUITE SOME TIME. THE DRY AIR FROM
THE HUDSON BAY HIGH WILL LIKELY LAST INTO FRIDAY NIGHT BEFORE SOME
PRECIPITATION POSSIBLY MAKES IT INTO AT LEAST THE SW HALF OF THE
REGION. DO THINK IT IS POSSIBLE THAT THE DRY HIGH PRESSURE SYSTEM
COULD HOLD OFF THE PRECIPITATION THROUGHOUT THE WEEKEND AND MAYBE
EVEN INTO THE FIRST PART OF THE UPCOMING WORK WEEK. THE ECMWF IS
MOST DRY ACROSS THE AREA...WITH THE GFS AND GEM BRINGING SOME
PRECIPITATION INTO THE CWA. HIGH TEMPERATURES WILL LARGELY BE IN THE
60S FOR THE ENTIRE EXTENDED WITH COOLER TEMPS NEAR LAKE SUPERIOR.

&&

.POINT TEMPS/POPS...
DLH  49  41  57  41 /  90  60  50  10
INL  52  40  66  39 /  60  30  10   0
BRD  56  45  61  44 /  60  60  50  10
HYR  62  44  56  42 /  60  60  60  20
ASX  48  40  52  40 / 100  60  60  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 11 AM CDT WEDNESDAY FOR LSZ121-
     140>148.

&&

$$

SHORT TERM...GROCHOCINSKI