Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 191410
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
910 AM CDT FRI SEP 19 2014

.UPDATE...
ISSUED AT 910 AM CDT FRI SEP 19 2014

MAIN CHANGE WAS TO ADD A MENTION OF FOG ALONG THE NORTH SHORE FROM
SILVER BAY TO GRAND PORTAGE. CKC CONTINUES TO CARRY BR WITH VSBYS
IMPROVING. RAIN SHIELD HAS REACHED THE WESTERN FA AS OF 14Z. MADE
SOME MINOR ADJUSTMENTS FOR THE LATEST TRENDS.

UPDATE ISSUED AT 649 AM CDT FRI SEP 19 2014

ADDED AREAS OF FOG/DRIZZLE ALONG ELEVATED TERRAIN OF COOK COUNTY.
LOW LVL COND PRESS DEFICITS HAVE DROPPED TO LESS THAN 10 MB DUE
TO TERRAIN LIFT OF LONG-FETCHED BDRY LYR FLOW.

&&

.SYNOPSIS...
ISSUED AT  339 AM CDT FRI SEP 19 2014

A STRONG WARM ADVECTION REGIME CONTINUES OVER THE CWA EARLY THIS
MORNING. EXTENSIVE LOW STRATUS IS LOCATED FROM NEAR THE TWIN PORTS
NORTH INTO THE ARROWHEAD. ALOFT...A LARGE AREA OF MID  LVL CLOUD
COVER IS ADVECTING EAST ACROSS NE MN INTO NWRN WISC. A MIGRATORY
SHORTWAVE TROF IS MOVING ALONG THE TOP OF THE MID LVL RIDGE OVER THE
NRN PLAINS. ASSOCIATED 60/65KT LLJ HAS TRANSLATED INTO NWRN ONTARIO
WHERE AN AREA OF CONVECTION IS LOCATED. WEAK RADAR RETURNS ARE
DEVELOPING WEST OF CWA AND WILL BRING A FEW SHOWERS INTO WRN CWA
BEFORE DAWN. THIS AREA OF SHOWERS APPEARS TO BE LINKED TO AN
EXTENSION OF THE 85H MSTR TRANSPORT MAXIMUM STRETCHING SOUTH FROM
ONTARIO.

&&

.SHORT TERM...(TODAY AND TOMORROW)
ISSUED AT 339 AM  CDT FRI SEP 19 2014

TODAY...PROGRESSIVE SHORTWAVE WILL DRAG LLJ AXIS EASTWARD ACROSS THE
REGION. GENERAL IDEA IS THAT HIGHEST POPS WILL OCCUR OVER NWRN CWA
THRU 18Z...AND THEN SHIFT ACROSS ARROWHEAD AND ERN CWA DURING THE
AFTN HRS. CONVECTIVE POTENTIAL IS LIMITED BASED ON FCST MLCAPE AND
MUCAPE FIELDS ALTHOUGH DEEP LAYER SHEAR IS QUITE SUFFICIENT TO
PROMOTE ORGANIZATION IF CELLS WERE TO DEVELOP. A SIGNIFICANT
AMOUNT OF CIN IS DEPICTED IN ELEVATED CAPE AREAS SO IT MAY BE
TOUGH TO GET MUCH DEVELOPMENT. MOST LIKELY POTENTIAL DEVELOPS
AFTER 00Z OVER WCTRL CWA.

TONIGHT..A NARROW WINDOW OF CONVECTIVE POTENTIAL OCCURS FROM CASS
LAKE TO TWIN PORTS 03Z-06Z AS MUCAPES OF NEAR 1500 J/KG ALIGN WITH
45KT 0/6KM SHEAR. AFTER 06Z...THERE IS A POTENTIAL FOR ADDITIONAL
CONVECTION TO MOVE QUICKLY SE ACROSS HYR LAKES VICINITY INTO PRICE
COUNTY. REGARDING THE OVERALL BDRY LYR CONVERGENCE ...IT IS NOT VERY
ORGANIZED AND UNIDIRECTIONAL FLOW IS FORECAST WITHIN THE LOWEST 5K
FEET. OTHERWISE THE FRONTAL BDRY WILL SWING ACROSS CWA WITH
WIND SHIFT TO W AND NW AND MOMENTUM TRANSFER INCREASING. HIGHER POPS
REMAIN ALONG INTL BORDER THROUGH 06Z...CLOSER TO DEEPER CYCLONIC
CURVATURE UNDERNEATH AMPLIFYING MID LVL TROF.

SATURDAY..INTERESTING PATTERN AS INITIAL FORCING MOVES EAST OF
REGION WITH A BRIEF BREAK IN PRECIP OVER MOST OF WRN/CTRL CWA. A
STRONG SHORTWAVE WILL RAVE INTO THE REGION BY AFTN WITH INSTABILITY
DEVELOPING AS LAPSE RATES STEEPEN DUE TO BDRY LYR WARMING AND
COOLING ALOFT. SREF CPTP INDICATES MDT PROB OF THUNDER OVER MOST OF
THE NE MN ZONES THROUGH 21Z...AND FARTHER SOUTHEAST THROUGH 03Z. A
NARROW AXIS OF LOW LVL THERMAL RIDGING AHEAD OF THE APPROACHING TROF
MAY ALLOW TEMPS TO CLIMB QUICKLY OVER SRN CWA TO LOW TO MID 70S SO
FCST TEMPS MAY NEED TO BE ADJUSTED UPWARDS.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT  339 AM CDT FRI SEP 19 2014

A VORT MAX ASSOCIATED WITH A H50 TROUGH AXIS WILL DROP OVER THE
WESTERN LAKE SUPERIOR REGION SATURDAY NIGHT INTO SUNDAY MORNING.
THE UNSTABLE CYCLONIC FLOW AND COOLING ALOFT WILL KEEP A CHC FOR
SHOWERS AND A FEW THUNDERSTORMS OVER MUCH OF THE NORTHLAND DURING
THIS TIME. A BROAD AREA OF UPPER LVL RIDGING BUILDS INTO THE
CENTRAL CONUS MONDAY...GRADUALLY SHIFTING EAST...CENTERING OVER
THE GREAT LAKES/OHIO RIVER VALLEY...THROUGH MID-WEEK. THE RIDGE
AND ASSOCIATED SFC HIGH WILL KEEP THE FCST DRY WITH SEASONABLE
TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK.

FOCUS TURNS TO A SHORT WAVE THAT TRANSLATES ACROSS THE DAKOTAS...AND
INTO NW MINNESOTA TUESDAY NIGHT/WEDNESDAY. THERE REMAINS MODEL
DIFFERENCES IN THE TIMING AND STRENGTH OF THE WAVE AS IT TRACKS OVER
THE NORTHLAND. ATTM...CARRYING BROAD BRUSH SCHC POPS WED NIGHT AND
THURSDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1222 AM CDT FRI SEP 19 2014

THERE WAS WIDESPREAD LIFR/IFR CIGS OVER NORTHEAST
MINNESOTA...INCLUDING THE KDLH/KHIB/KINL AREAS. THE KBRD AND KHYR
AREAS HAD VFR CONDITIONS. THE NORTHLAND HAD SE WINDS AROUND 10 KNOTS.

THE WINDS WILL INCREASE AND BECOME SOUTHERLY OVERNIGHT AND FRIDAY
MORNING. A STRONG SSW LOW LEVEL JET...ABOUT 40 TO 50 KNOTS...WILL
DEVELOP OVERNIGHT. THE FORECASTS INCLUDE LLWS THROUGH THE NIGHT.
WHILE THERE MAY BE SOME GUSTS LATER TONIGHT...DO NOT BELIEVE THE
BOUNDARY LAYER WILL BE SUFFICIENTLY MIXED TO DROP THE LLWS UNTIL
DAWN.

GUSTY SOUTHERLY WINDS WILL DEVELOP OVER THE REGION FRIDAY AS THE
BOUNDARY LAYER MIXES OUT WITH DAYTIME HEATING. THE STRONGEST WINDS
MAY BE OVER NW WISCONSIN...INCLUDING KHYR WHICH COULD SEE GUSTS
APPROACH 30 KNOTS. THERE WILL BE INCREASING LOW LEVEL
SATURATION...WHICH WILL LIKELY RESULT IN LOW CIGS AND A TRANSITION
TOWARDS MVFR CIGS. AN APPROACHING FRONT IN THE NORTHERN PLAINS
WILL BRING SHOWERS...MAYBE STORMS...THROUGH THE NORTHLAND
TOMORROW. CONFIDENCE ON THE DEVELOPMENT...LET OUT ALONE
TIMING...OF STORMS IS LOW. THEREFORE LEFT OUT STORMS IN THE
FORECAST FOR NOW. THE WIDESPREAD MVFR CIGS WILL LIKELY CONTINUE
THROUGH THE EARLY FRIDAY EVENING.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  64  58  68  52 /  60  50  60  30
INL  69  54  65  47 /  70  70  60  70
BRD  68  58  71  49 /  60  20  40  10
HYR  66  61  70  49 /  60  50  40  30
ASX  67  60  68  50 /  60  50  30  40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ140-
     141.

&&

$$

UPDATE...GSF
SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...GRANING
AVIATION...GROCHOCINSKI/MCLOVIN






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