Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KMKX 250254
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
954 PM CDT SUN MAY 24 2015

.UPDATE...LINES OF HEAVY RAIN SHOWERS AND ISOLD TSTORMS WILL
CONTINUE TO STREAM NWD INTO SRN WI VIA THE WARM CONVEYOR BELT INTO
MON AM. THIS IS AHEAD OF THE APPROACHING UPPER TROUGH THAT IS
CURRENTLY OVER ERN KS AND ERN OK. A WAVE OF LOW PRESSURE AND
ASSOCIATED LOW TO MID LEVEL WARM ADVECTION WILL ACCOMPANY THE
UPPER TROUGH REACHING THE VICINITY OF THE IA...MN...WI BORDER
AROUND 12Z. THUS THE RAINFALL WILL LIKELY BE MORE WIDESPREAD AND
INTENSE OVER THE WRN CWA AT THAT TIME. AS THE LOW SHIFTS INTO NRN
WI BY 18Z THE WINDS WILL SHIFT SWLY AND BECOME GUSTY. THIS WILL
MARK THE END OF THE RAIN THREAT AND BRING A WARM AND PARTLY CLOUDY
DAY.


&&

.AVIATION/06Z TAFS/...CIGS OVER SOUTH CENTRAL WI WILL BE MAINLY
BELOW 1 KFT INTO MON AM WITH PREVAILING MVFR VSBYS BUT LOWER AT
TIMES IN HEAVIER RAIN SHOWERS. PREVAILING CIGS WILL FALL TO 1-3
KFT OVER SE WI DURING THE EARLY MORNING HOURS OF MON WITH MVFR
VSBYS DEVELOPING AS WELL. CIGS AND VSBYS WILL BE LOWER AT TIMES IN
THE HEAVIER SHOWERS AS WELL. LOW PRESSURE WILL TRACK NORTH TO
NORTHEAST THROUGH ERN IA INTO NRN WI THROUGH MON AM BRINGING THE
RAIN BUT WILL SHIFT THE WINDS TO THE SW BTWN 13-16Z. THIS WILL
MARK THE END OF THE RAINFALL BUT ALSO BRING DRIER AND WARMER AIR
TO SRN WI. THUS PARTLY  CLOUDY SKIES AND VFR CONDITIONS ARE
EXPECTED BY AFTERNOON. LLWS IS EXPECTED EARLY MON AM DUE TO A
SSWLY 40-50 KT LLJ.


&&

.PREV DISCUSSION... /ISSUED 331 PM CDT SUN MAY 24 2015/

TONIGHT AND MONDAY...FORECAST CONFIDENCE IS MEDIUM.

TRICKY FORECAST FOR TONIGHT. CURRENT AREA OF RAIN CONTINUES TO MOVE
NORTH NORTHEASTWARD THROUGH THE AREA...DRIVEN BY 850 MB TO 700 MB
WARM AIR ADVECTION/LOW LEVEL JET NOSE. MESOSCALE MODELS HAVE THIS
AREA OF PRECIPITATION MOVING OUT OF THE AREA BY 00Z MONDAY.

HOWEVER...MORE CELLULAR SHOWERS AND A FEW STORMS HAVE DEVELOPED
ACROSS NORTHERN ILLINOIS AND INTO SOUTHEAST IOWA/WEST CENTRAL
ILLINOIS. MESOSCALE MODELS SHOW THIS ACTIVITY INCREASING IN AREAL
COVERAGE AND SHIFTING INTO THE AREA THIS EVENING...LINGERING THROUGH
MOST OF THE EVENING. THIS IS OCCURRING AS THE WARM FRONT MOVES NORTH
THROUGH THE AREA. AREA FORECAST SOUNDINGS ARE SHOWING JUST VERY
NARROW MEAN LAYER OR ELEVATED CAPE THROUGH THIS EVENING. THUS...WENT
WITH HIGHER END POPS FOR SHOWERS THIS EVENING...WITH ISOLATED
THUNDER.

MESOSCALE MODELS THEN INDICATE ANOTHER BATCH OF SHOWERS AND A FEW
STORMS FOR LATER TONIGHT INTO MONDAY MORNING. THIS IS IN RESPONSE TO
THE CONTINUED MOIST CONVEYOR BELT FLOW INTO THE REGION...AND A
STRONG 500 MB VORTICITY MAXIMUM APPROACHING AND MOVING NORTHEAST
THROUGH THE AREA. THUS...WILL CONTINUE HIGHER END POPS FOR THIS
PERIOD IN THE FORECAST...CARRYING ISOLATED THUNDER.

MODELS THEN CONTINUE TO SHOW DRY SLOTTING OCCURRING ACROSS THE AREA
LATER MONDAY MORNING INTO THE AFTERNOON. SO...WILL LEAN TOWARD A DRY
LOOK FOR THIS PERIOD.

STRONG MIXING WITH THE DRY SLOT WILL LEAD TO WINDY CONDITIONS.
SOUTHWEST WINDS SHOULD GUST IN THE 28 TO 34 KNOT RANGE DURING THE
AFTERNOON. WENT WITH A MIX OF THE GFS/NAM SOUNDINGS WITH THE GUSTS.
GFS INDICATED WIND ADVISORY LEVEL GUSTS...BUT THOUGHT THEY WERE TOO
HIGH. PARTIAL CLEARING AND THE GUSTY SOUTHWEST WINDS WILL LEAD TO
WARM TEMPERATURES IN THE 80 TO 83 DEGREE RANGE ACROSS MOST
AREAS...INCLUDING LAKESHORE LOCATIONS.

MONDAY NIGHT - CONFIDENCE...MEDIUM
SHORT WAVE RIDGING TAKES HOLD ON ALL MODELS EXCEPT THE
GEM...WHERE A SUSPICIOUSLY STRONG VORT ARRIVES BETWEEN 6-12Z. THE
LLJ IS LIFTING OUT PLACING THE CWA IN THE UNFAVORABLE ENTRANCE
REGION. BOTH THE GFS AND NAM SHOW PRECIP DURING THE EVENING WITH
SOME BETTER LLVL CONVERGENCE COMBINED WITH LINGERING DIURNALLY
DRIVEN INSTABILITY. THE NAM SUGGESTS THAT CONVECTION COULD DRIFT
ACROSS THE CWA THE BALANCE OF THE NIGHT ALONG SURFACE BOUNDARY.
THE OTHER MODELS SUGGEST A MORE ESTABLISHED SOUTHERLY FLOW WITH
LITTLE CONVERGENCE AND THE DEPARTING 850 JET CORE. WILL KEEP SOME
POPS GOING.

TUESDAY AND TUESDAY NIGHT - CONFIDENCE...MEDIUM
ALL MODELS EXCEPT THE GEM BRING SHORTWAVE ENERGY NORTHEAST INTO
THE CWA DURING THE AFTERNOON/EVENING. THIS ENERGY RIDES IN AHEAD
OF THE MAIN TROUGH AXIS ACROSS MN/IA. THIS TROUGH APPROACHES
DURING TUESDAY NIGHT. APPESRS BEST WINDOW FOR SHRA/TSRA WILL BE
18-06Z...WITH A DROPOFF AFTER 06Z. CAPE PROFILE APPEARS TALL AND
SKINNY ON THE NAM AND GFS BUFKIT SOUNDINGS SO AT THIS TIME THE SVR
THREAT LOOKS LOW...WHICH IS IN LINE WITH SPC/S MARGINAL IDEA.

WEDNESDAY - CONFIDENCE...LOW
12Z GFS/00Z ECMWF SHOW A QUICKER PROGRESSION ON THE PRIMARY MID
LEVEL TROUGH AXIS. MEANWHILE THE 12Z NAM/12Z GEM SHOW A SLOWER
MOVEMENT. IN THE LATTER CASE THIS RESULTS IN ANOTHER CHANCE OF
STORMS DUE TO THE FAVORABLE PLACEMENT OF THE TROUGH AXIS FOR RE-
ENERGIZING CONVECTION. IN THE GFS/ECMWF SCENARIO A QUIETER PERIOD
EVOLVES WITH SOME NVA AND WEAK SURFACE RIDGING. THE 12Z GFS/00Z
ECMWF SUGGEST THE QUIET TREND FROM WEDNESDAY WOULD CARRY OVER INTO
WEDNESDAY NIGHT...WITH AN EXTRAP OF 84 HR NAM SUGGESTING POTENTIAL
FOR SOME EARLY EVENING CONVECTION.

THURSDAY - CONFIDENCE...MEDIUM
WARM WITH MID LEVEL RIDGING BRIEFLY TAKING HOLD. 925 TEMPS AROUND
20C. SHORTWAVE ACTIVITY LOOKS LIKE IT WILL STAY OFF TO THE WEST
FOR THE DAYTIME HOURS. 12Z GFS DOES SHOW PRECIP INTO THE WESTERN
CWA AND SUPERBLEND ACCOUNTS FOR THIS SO WILL HAVE SMALL POPS FOR
NOW THERE BUT KEEP THE EAST LARGELY DRY.

THURSDAY NIGHT THROUGH SATURDAY - CONFIDENCE...LOW
LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY PROGGD TO AFFECT THE
AREA THIS PERIOD. MAIN ISSUE CENTERS AROUND THE OVERALL TIMING.
THE GFS IS QUICKER TO BRING THIS FRONT INTO THE AREA...WHILE THE
ECMWF IS SLOWER TO BRING IT IN AND THEN LINGERS IT LONGER. IN FACT
THE GFS SHOWS HIGH PRESSURE IN PLACE BY SATURDAY WHILE THE ECMWF
SHOWS A SECONDARY LOW DEVELOPING ACRS NRN IL WITH WIDESPREAD
PRECIP INTO SRN WI. FOR NOW WILL RIDE WITH THE SUPERBLEND POPS AND
HOPE FOR BETTER CONSENSUS IN FUTURE MODEL RUNS.

SUNDAY - CONFIDENCE...MEDIUM
BOTH MODELS SHOW HIGH PRESSURE EXERTING A GREATER INFLUENCE ACRS
WI. IN THE UPPER LEVELS THE GFS SHOWS SUSPISCIOUSLY STRONG VORTS
WELL NORTH OF KS CLOSED LOW. MEANWHILE THE ECMWF SHOWS A SLIGHTLY
MORE OPEN SYSTEM WITH A MUCH CLEANER LOOKING VORT PATTERN. WILL
STEER TOWARDS THE LATTER.

AVIATION/00Z TAFS/...AREA OF RAIN WILL AFFECT TAF SITES THROUGH
LATE THIS AFTERNOON...WITH MAINLY VFR CATEGORY CONDITIONS EXPECTED.
WINDS WILL BE LIGHT AND EASTERLY. MORE SHOWERS AND A FEW STORMS
SHOULD THEN MOVE INTO THE AREA DURING THE EVENING. CONTINUED
SHOWER MENTION IN TAFS DURING THIS TIME...AS A WARM FRONT MOVES
NORTH THROUGH THE AREA. WINDS WILL SHIFT TO THE SOUTH LATER
TONIGHT INTO EARLY MONDAY MORNING AFTER THE FRONT MOVES THROUGH.

ANOTHER AREA OF RAIN AND A FEW THUNDERSTORMS SHOULD THEN PUSH INTO
THE AREA AFTER MIDNIGHT AND INTO MONDAY MORNING...WITH A TROUGH OF
LOW PRESSURE. SOME UNCERTAINTY WITH THE CEILINGS AND VISIBILITIES
DURING THIS PERIOD...AS SHORT TERM MODELS ARE QUITE AGGRESSIVE WITH
LOWERING THEM. FOR NOW...WILL LEAN TOWARDS MVFR CATEGORY CEILINGS
AND VISIBILITIES AT TAF SITES.

REMOVED LOW LEVEL WIND SHEAR FROM TAFS TONIGHT...AS LOW LEVEL JET
MAY NOT BE AS STRONG AS PREVIOUSLY THOUGHT. STILL...2000 FOOT LEVEL
WINDS SHOULD BE SOUTHWEST AT 30 TO 35 KNOTS.

WINDS WILL THEN SHIFT SOUTHWEST AND BECOME GUSTY DURING THE
AFTERNOON...WITH GUSTS OF 28 TO 34 KNOTS POSSIBLE. VFR CONDITIONS
ARE EXPECTED IN THE LATE MORNING AND AFTERNOON...WITH CEILINGS
SCATTERING OUT.

MARINE...HIGHER DEW POINTS MOVING INTO THE REGION TONIGHT INTO MONDAY
WILL MOVE OVER THE COOL LAKE MICHIGAN WATERS. THIS SHOULD RESULT IN
AREAS OF FOG FORMING TONIGHT...REMAINING PATCHY INTO MONDAY. SOME
QUESTION IF THE FOG WILL LINGER MONDAY...WITH GUSTY SOUTHWEST WINDS
BATTLING MARINE INVERSION LAYER. DENSE FOG IS POSSIBLE TONIGHT
INTO EARLY MONDAY.

GUSTY SOUTHWEST WINDS ARE EXPECTED MONDAY INTO MONDAY EVENING...AS A
TIGHT PRESSURE GRADIENT DEVELOPS ACROSS THE REGION. FREQUENT GUSTS
OF 25 TO 30 KNOTS ARE EXPECTED ACROSS THE NEARSHORE WATERS DURING
THIS TIME...ESPECIALLY NEAR THE SHORELINE. THE GUSTS WILL BE A BIT
LOWER THAN OVER LAND...DUE TO THE MARINE INVERSION. THUS...A SMALL
CRAFT ADVISORY CONTINUES FOR THIS PERIOD. HIGHEST WAVES WILL BE
TOWARD THE OPEN WATERS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 7 AM MONDAY TO 4 AM CDT TUESDAY FOR
     LMZ643>646.

&&

$$

UPDATE...GEHRING
TONIGHT/MONDAY AND AVIATION/MARINE...WOOD
MONDAY NIGHT THROUGH SUNDAY...COLLAR


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.