614
FXUS63 KDLH 240842
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
342 AM CDT THU JUL 24 2008
DISCUSSION
ANOMALOUS UPPER LOW OVER ERN GT LAKES HAS BLOCKED THE WESTERLIES
EARLY THIS MORNING. AN AREA OF UPPER DIFFLUENCE IS DEVELOPING
ACROSS CWA. LATEST WV IMAGERY/RUC13 SHOWS INITIAL SHORTWAVE
ROTATING NE INTO ONTARIO UNDER INCREASING DIFFLUENT FLOW. 88D RETURNS
OVER NORTH COUNTRY MAINLY INDICATIVE OF MID LVL MOISTURE AS 0Z INL
SOUNDING WAS VERY DRY. A LINE OF CONVECTION HAS FORMED NEAR ND/MN
BORDER WITHIN AN AXIS OF 85H THETAE. RUC13 ALSO INDICATES A NARROW
TONGUE OF MID LVL WARMING HAS DEVELOPED BEHIND CONVECTION.
TODAY/TONIGHT...INITIAL SHORTWAVE WILL WEAKEN AS IT MOVES ACROSS CWA.
TOUGH CLOUD FCST AS THINNING OF DEEP LAYER MOISTURE MAY ALLOW
VARYING AMNTS OF SUNSHINE. A FAIRLY WELL DEFINED SFC/85H THETAE
AXIS OVER ND WILL TRY TO MOVE EAST. HOWEVER...IT SEEMS THAT MDLS
SUGGEST INITIAL THERMAL AXIS MAY ONLY GET SO FAR AND STALL OVER
WRN HALF OF CWA....WHILE A SECOND AXIS FORMS IN RESPONSE TO
SECONDARY...AND STRONGER... MID LVL DISTURBANCE. OVERALL SYNOPTIC
SUPPORT FOR ASCENT IS MEAGER WITH MAIN UPPER JET TRAVERSING WELL
SOUTH OF REGION. HAVING SAID THAT...INTERESTING TO NOTE THAT MDLS
ARE IN AGREEMENT THAT ATMOSPHERE WILL CONTINUE TO DESTABILIZE
TODAY AS FAIRLY HIGH PWS ENTER REGION. BY LATE AFTERNOON...4KM
NMM/WRF SIMULATED REFLECTIVITY PRODUCT GENERATES CONVECTION OVER
WRN CWA AND PUSHES THE DEVELOPMENT ESE OVERNIGHT. THIS APPEARS
REASONABLE CONSIDERING DEVELOPMENT OF NWLY MID LVL FLOW TONIGHT.
MDLS FCST SBCAPES INTO 1500/2000 J/KG RANGE LATE AFTERNOON INTO
EVENING OVER WRN THIRD OF CWA. GFS SIG SVR PARAMETER VALUES ARE
MAXIMIZED OVER CASS LAKE/BRAINERD LAKES VICINITY BY EARLY EVENING.
SPC HAS OUTLINED AN AREA WEST OF A CDD-HIB-MALMO LINE FOR SLIGHT
RISK OF SVR STORMS.
FRIDAY...MDLS DIVERGE ON AMPLITUDE/SPEED OF PRIMARY MID LVL
FEATURE...DEEPENING TROF. THIS IMPACTS CONFIDENCE ON CONVECTIVE
ASPECT OF FCST. EC WOULD PUSH INSTABILITY QUICKLY ACROSS CWA
FRIDAY...MINIMIZING SVRWX THREAT. GFS IS A BIT SLOWER/DEEPER WITH
TROF AND ALLOWS SIGNIFICANT INSTABILITY TO DEVELOP ACROSS SE ZONES
OF NW WISCONSIN. STEEPENING LAPSE RATES FRIDAY ACROSS ENTIRE CWA
AS MID LVL TROF MOVES OVERHEAD. SHOULD SEE SOME HAILERS/GUSTY WINDS.
EXTENDED...BRISK NWLY MID LVL FLOW DOMINATES WEEKEND. CURRENT FCST
IS DRY BUT WILL NEED TO WATCH FOR ISOLATED CONVECTION WITH VERY
STEEP LAPSE RATES. MSTR IS LIMITED SO IF RW/TRW DEVELOP...SHOULD
BE OVER ARROWHEAD. VERY PLEASANT TEMPS SAT/SUN. NEXT CHANCE OF
PRECIP MON NIGHT/EARLY TUESDAY PER GFS/EC.
AVIATION
SCATTERED SHOWERS WILL MOVE THROUGH NE MN EARLY THIS
MORNING WITH ISOLD CIGS IN THE MVFR RANGE. THE SHOWERS WILL SPREAD
INTO NW WI BY MID MORNING. A FEW THUNDERSTORMS ARE ALSO ANTICIPATED
ALONG AND AHEAD OF AN APPROACHING WARM FRONT. THE SHOWERS AND
THUNDERSTORMS WILL PERSIST INTO THE EVENING AS A WEAK COLD FRONT
APPROACHES FROM THE W. MVFR CIGS ARE POSSIBLE IN THE VICINITY OF THE
THUNDERSTORMS.
POINT TEMPS/POPS...
DLH 73 61 80 54 / 30 30 20 10
INL 77 58 78 53 / 30 20 20 10
BRD 82 63 83 55 / 30 30 20 10
HYR 77 61 83 53 / 30 30 30 10
ASX 72 60 81 55 / 30 30 30 10
DLH WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
LS...NONE.
CANNON/GSF
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