448
FXUS63 KDLH 130913
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
413 AM CDT TUE AUG 13 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY...
A NEGATIVELY TILTED LONG WAVE TROUGH OVER THE ERN GREAT LAKES WILL
KEEP THE NORTHLAND UNDER AN UPPER LVL NW FLOW TODAY. ALTHOUGH
PROFILES SHOW THE AIR MASS IS LACKING MOISTURE WITH A SFC RIDGE
APPROACHING THE FROM THE WEST...THE SEASONABLY COOL H85 TEMPS IN THE
SINGLE DIGITS WILL ALLOW FOR AFTERNOON CU DEVELOPMENT AND A POSSIBLE
SPRINKLE/LIGHT SHOWERS OVER THE FAR ERN ZONES. HAVE CARRIED A 20 POP
FOR MUCH OF TODAY ACROSS THE MN ARROWHEAD/NRN WISC ZONES WHERE
INSTABILITY IS THE GREATEST AND A VERY SHALLOW SATURATED LAYER
AROUND H80 MAY BE ENOUGH TO SUPPORT A SHOWER OR TWO.
CONDITIONS TONIGHT WILL BE FAVORABLE FOR STRONG RADIATIONAL COOLING
AS SFC RIDGING SETTLES OVERHEAD. HAVE LOWERED OVERNIGHT TEMPS A FEW
DEGREES TOWARDS THE LATEST MAV/MEX GUIDANCE WHICH ARE SUGGESTING MIN
TEMPS IN THE MIDDLE 30S TO LOW 40S. THE LAV/MET/ECM ARE RUNNING
SLIGHTLY WARMER...BRINGING MOST AREAS DOWN INTO THE LOW TO MIDDLE
40S.
WEAK MID LEVEL WARM AIR ADVECTION RETURNS WEDNESDAY WITH SLIGHTLY
WARMER TEMPERATURES AND DRY CONDITIONS.
EXTENDED...WEDNESDAY THROUGH MONDAY...
THE REMAINDER OF THE WEEK WILL BE DOMINATED BY A LARGE SFC HIGH
STRETCHING FROM SRN MANITOBA/ONTARIO TO THE OHIO VALLEY. A NW MID
LVL FLOW WILL PROVIDE SYNOPTIC SCALE SUBSIDENCE. AS A RESULT A
PERIOD OF QUIET WX IS EXPECTED ACROSS THE CWA. CHANGES OCCUR DURING
THE WEEKEND AS THE MID LVL PATTERN SHIFTS TO A DEVELOPING MID LVL
RIDGE OVERHEAD AND DOWNSTREAM TROUGHING IN THE SERN CONUS. AN
INCREASINGLY STRONGER WARM ADVECTION REGIME WILL DEVELOP FROM WEST
TO EAST SAT/SUN. ANTICYLONICALLY CURVED FLOW IN THE BDRY LYR
COMBINED WITH RIDGING ALOFT MAKES ANY ORGANIZED ASCENT DOUBTFUL.
HOWEVER LATEST FCST INSTABILITY AXIS AT 85H SUGGEST A FEW STRAY
SHOWERS OR STORMS MAY ERUPT SATURDAY BEFORE MORE SIGNIFICANT CAPPING
ARRIVES SUNDAY. MOST PROBABLE CHC OF PRECIP ARRIVES MONDAY AS A
FRONTAL SYSTEM IS CARRIED INTO THE CWA BY STRENGTHENING WESTERLY
FLOW ALOFT. TEMPS WILL AVERAGE NEAR CLIMO WED THROUGH FRIDAY AND
THEN A WARMING TREND IS EXPECTED FOR THE WEEKEND AS UPPER HEIGHTS
BUILD AND 85H TEMP VALUES INCREASE TO 15C TO 18C.
&&
.AVIATION...06Z TAF ISSUANCE...
VERY WEAK DISTURBANCE WILL DROP SOUTHWARD ACROSS THE MINNESOTA
ARROWHEAD AND NORTHWEST WISCONSIN TONIGHT AND TUESDAY MORNING.
HOWEVER...BROKEN VFR CEILINGS AND LIGHT SHOWERS SHOULD STAY TO AREAS
JUST NORTHEAST OF THE KHIB/KDLH/KHYR TERMINALS. CLEAR SKIES AND
LIGHT WINDS MAY ALSO RESULT IN SOME FOG FORMATION 08-13Z
TUESDAY..MOST NOTABLE AT THE FAVORED LOCATIONS OF KHYR/KHIB.
SCATTERED CUMULUS EXPECTED TO DEVELOP 14-16Z TUE..WITH PERHAPS A
BRIEF PERIOD OF BROKEN VFR CEILINGS FOR A COUPLE HOURS. CLOUD BASE
SHOULD LIFT THRU THE DAY AND BECOME SCATTERED BEFORE SKIES CLEAR
00-02Z WED. WINDS THRU THE PERIOD SHOULD BE LIGHT/VARIABLE OR
NORTHERLY AROUND 10KT OR LESS TUE AFTERNOON.
&&
.POINT TEMPS/POPS...
DLH 73 46 73 49 / 10 0 0 0
INL 71 36 72 44 / 0 0 0 0
BRD 76 46 77 50 / 0 0 0 0
HYR 72 40 74 46 / 10 0 0 0
ASX 70 40 71 50 / 20 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GRANING
LONG TERM....CANNON