735
FXUS63 KMKX 041913
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
213 PM CDT SAT JUL 4 2009
LOW LEVEL INSTABILITY IS IMPRESSIVE THIS AFTERNOON ACROSS THE
NORTHERN CWA. THE NON-SUPERCELL TORNADO PARAMETER IS SHOWING
FAVORABLE NUMBERS FOR THE GENERATION OF FUNNELS. IT IS NOT OUT OF
THE QUESTION ONE OR MORE OF THESE WILL TOUCH DOWN BEFORE SUNSET.
THE ARE TYPICALLY VERY WEAK AND DO LITTLE DAMAGE. LLV LAPSE RATES
/0-1KM/ ARE CLOSE TO DRY ADIABATIC WITH DECENT 0-3KM CAPES. BULK
SHEAR IS VERY WEAK...IN FACT NEARLY ALL BELOW 5KTS BELOW H7. THERE
IS A VERY WEAK SFC BNDRY STRETCHING FROM NRN OZAUKEE COUNTY UP
THROUGH COLUMBIA/GREEN LAKE AND MARQUETTE COUNTIES. THIS SHOULD BE
THE MAIN FOCUS FOR ISOLATED SHOWERS AND STORMS. THESE STORMS HAVE
DEVELOPED RAPIDLY...THEN COLLAPSE JUST AS QUICKLY. IT IS ON THE UP
STROKE OF THE STORM THAT WE HAVE GOTTEN A FUNNEL REPORT. IT SHOULD
GET MORE COMPLICATED AS THE VARIOUS OUTFLOW BOUNDARIES FROM THESE
SHOWERS/STORMS BEGIN TO INTERACT AND IF MORE BREAKS IN THE
OVERCAST OFFER MORE HEATING. ALL OF THIS SHOULD DISSIPATE AS THE
DIURNAL INFLUENCE WANES WITH SUNSET.
HAVE INTRODUCED A SMALL CHANCE FOR PRECIP ACROSS THE NORTHEAST CWA
ON SUNDAY AS A WEAK TROF DRIFTS SOUTHEAST ACROSS THE GREAT LAKES
AND CLIPS THE CWA. NOT SURE IF THERE WILL BE ENOUGH MOISTURE TO
WORK WITH...BUT THE MODELS HAVE BEEN HINTING AT SOME LIGHT QPF.
THE GFS IS LIKELY OVERDONE AND THIS APPEARS DUE TO IT/S GENEROUS
SFC DWPNTS. THE NAM IS LOOKING BETTER W.R.T. DWPNTS.
THE MODELS BEGIN TO THROW IN MORE UNCERTAINTY BEYOND MONDAY THAN
WHAT WAS DEPICTED PREVIOUSLY. THE NAM IS BLOWING UP AN MCS MONDAY
NIGHT INTO TUESDAY MORNING FOR THE CWA WITH A STRONGER MID LEVEL
S/W PASSING THROUGH THE NW FLOW...RESULTING IN A BETTER LLV JET AND
WARM AIR ADVECTION. THE GFS IS QUIET DURING THIS TIME PERIOD. THE
NAM THEN PUSHES THE H8 BAROCLINIC ZONE BACK FARTHER TO THE WEST
WITH QUIET WEATHER IMPLIED THEREAFTER FOR A TIME. THE GFS
MAINTAINS THE BAROCLINIC ZONE CLOSER TO THE CWA AND THEN BRINGS
PROPOGATING MCS/S THROUGH THE AREA TUESDAY INTO THURSDAY. THIS LARGE
UNCERTAINTY IS NEW WHILE THE 00Z/12Z ECMWF MAINTAINS THE UPPER
RIDGE WITH QUIET WEATHER FROM MONDAY THROUGH ABOUT THURSDAY. WILL
STAY THE COURSE WITH THE QUIETER FORECAST UNTIL MORE CONTINUITY
SHOWS UP IN THE MODELS. I DON/T WANT TO CHASE THESE NEBULOUS PCPN
BOMBS THIS FAR OUT...EXPECIALLY GIVEN THE POOR MODEL PERFORMANCE
IN THESE SITUATIONS.
AVIATION
THE BULK OF THE SHOWERS THAT MOVED THROUGH SOUTHERN
WISCONSIN HAVE NOW PUSHED SOUTH OF THE STATE. ISOLATED STRONGER
SHOWERS POPPED UP THIS AFTERNOON NORTH OF I-94...AND ARE EXPECTED TO
REMAIN MOSTLY NORTH OF THE INTERSTATE. EXPECT THESE SHOWERS TO
LINGER INTO EARLY EVENING...UNTIL DAYTIME HEATING IS LOST. VFR
CONDITIONS WILL PREVAIL THROUGH THE EVENING...WITH CIGS POSSIBLY
LOWERING TO MVFR IN ANY STRONGER SHOWERS. BY LATE THIS
EVENING...SHOWERS WILL BE COMPLETELY OUT OF THE STATE...WITH
CLEARING SKIES. WITH LIGHT WINDS EXPECTED...SOME LIGHT FOG MAY
DEVELOP LATER TONIGHT IF SKIES CLEAR OUT ENOUGH...WITH MVFR VISBYS
POSSIBLE. FAIR WEATHER WILL THEN BRING VFR CONDITIONS THROUGH THE
DAY TOMORROW.
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
SHORT/LONG TERM...DAVIS
AVIATION/MARINE...VANCLEVE
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