273
FXUS63 KMKX 240846
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
346 AM CDT THU JUL 24 2008
FORECAST FOCUS ON PRECIPITATION CHANCES TODAY THROUGH FRIDAY
NIGHT.
LATEST WATER VAPOR IMAGERY INDICATED A CUTOFF UPPER LEVEL LOW OVER
SOUTHEAST ONTARIO CANADA...WITH AN UPSTREAM RIDGE OVER THE
NORTHERN PLAINS. AT THE SURFACE...HIGH PRESSURE WAS MOVING SOUTH
ACROSS THE AREA. CONVECTION FROM SOUTHEAST SOUTH DAKOTA TO
SOUTHERN IOWA IN AREA OF WARM FRONT AND LOW LEVEL JET NOSE.
SHORT TERM...TODAY THROUGH FRIDAY NIGHT
AFOREMENTIONED CONVECTION OVER THE PLAINS EXPECTED TO STAY WELL
SOUTHWEST OF THE AREA TODAY. WEAK WARM AIR ADVECTION TRYING TO GET
SOME SHOWERS TO DEVELOP OVER THE WESTERN HALF OF WISCONSIN AND
INTO EASTERN MINNESOTA AND NORTHEAST IOWA. DRY LOW TO MID LEVELS
PER AREA FORECAST SOUNDINGS PREVENTING ANYTHING FROM REACHING THE
GROUND.
WILL CONTINUE TO CARRY A SLIGHT CHANCE POP FOR THE SOUTHWEST
COUNTIES TODAY...AS THIS AREA IS CLOSEST TO SHOWER ACTIVITY OVER
EASTERN MINNESOTA AND NORTHEAST IOWA. HOWEVER...MOST OF THE DAY
SHOULD REMAIN DRY ACROSS THE AREA. WINDS SHOULD TURN ONSHORE THIS
AFTERNOON NEAR THE LAKE...BRINGING COOLER TEMPERATURES THERE.
WARM AIR ADVECTION IN LOW LEVELS BECOMES MORE ROBUST TONIGHT AND
FRIDAY ACROSS THE AREA. NO REAL DEFINED BOUNDARIES OR SHORTWAVES
TONIGHT...BUT SOME WEAK ELEVATED INSTABILITY DEVELOPS OVERNIGHT.
WILL CONTINUE THE LOW CHANCE POPS...BUT WOULD NOT BE SURPRISED TO
HAVE ANOTHER QUIET NIGHT.
WEAK COLD FRONT THEN DROPS SOUTH ACROSS THE AREA MAINLY LATE
FRIDAY AND FRIDAY NIGHT. MOISTURE ADVECTING INTO THE AREA HELPS
INCREASE MEAN LAYER CAPES INTO THE 1000 TO 2000 J/KG RANGE LATE
FRIDAY...WITH MODEST DEEP LAYER 0-6KM SHEAR OF 30 TO 35 KNOTS. SPC
SLIGHT RISK IN FAR WESTERN COUNTIES FOR FRIDAY AND FRIDAY EVENING.
LACK OF AN UPPER LEVEL SHORTWAVE OR JET STREAK CIRCULATION WOULD
BE A NEGATIVE FOR WIDESPREAD CONVECTION. WILL MAINTAIN CHANCE POPS
FOR FRIDAY AND FRIDAY EVENING...TAPERING OFF LATER FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH WEDNESDAY
GFS AND ECMWF KEEPING AREA DRY FOR THE WEEKEND INTO EARLY NEXT
WEEK...AS ANOTHER CANADIAN HIGH DROPS SOUTHEAST THROUGH THE AREA.
PLEASANT TEMPERATURES ARE EXPECTED THROUGH THIS PERIOD. MODELS
INDICATING SOME POTENTIAL FOR A SYSTEM PASSING THROUGH THE REGION
TUESDAY AND TUESDAY NIGHT...BUT WILL KEEP THIS PERIOD DRY FOR
NOW...AS THERE ARE DIFFERENCES BETWEEN THE GFS AND ECMWF WITH
PLACEMENT OF SHORTWAVE TROUGH.
AVIATION
LARGE SURFACE HIGH CENTERED OVER WISCONSIN THIS MORNING. PATCHY
FOG POSSIBLE IN LOW LYING AREAS AND IN RIVER VALLEYS EARLY...BUT
INCREASING CIRRUS WILL TEND TO DIMINISH IDEAL RADIATION
CONDITIONS...ESPECIALLY WEST AREAS.
WEAK LOW LEVEL RETURN FLOW SHOULD RESULT IN LIMITED RETURN OF
INSTABILITY. EXPECT SCATTERED CUMULUS AROUND 5 THSD FT WITH
HIGH/MID LEVEL CLOUDS THIS AFTERNOON. SHOWER/THUNDERSTORM
POTENTIAL LOW TONIGHT WITH LIMITED MOISTURE AND LOW LEVEL FLOW.
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
SHORT/LONG TERM...08/WOOD
AVIATION/MARINE...06/HENTZ
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