000
FXUS63 KMKX 112026
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
326 PM CDT SAT MAY 11 2013

.SHORT TERM...

TONIGHT...FORECAST CONFIDENCE MEDIUM

ANY LINGERING INSTABILITY SHOWERS EXPECTED TO DISSIPATE WITH LOSS
OF HEATING. MAIN CONCERN IS WHETHER TEMPS WILL DROP BELOW
FREEZING. AIRMASS WILL REMAIN MIXED AS SURFACE/850 GRADIENT
REMAINS FAIRLY TIGHT. MAJORITY OF BLENDED/BIAS CORRECTED GUIDANCE
SUGGESTS TEMPS REMAIN ABOVE FREEZING FOR MOST OF THE CWA. PRIMARY
CONCERN IS WEST AND NORTH OF MADISON WHERE SOME...THOUGH NOT
ALL...GUIDANCE SUGGESTS TEMPS COULD SLIP BELOW 32. WILL HOLD OFF
ON ANY HEADLINE PER COORD WITH ARX/GRB. WITH LOW LEVELS EXPECTED
TO BE FAIRLY WELL MIXED NOT A GREAT SETUP FOR FROST DEVELOPMENT.

SUNDAY...FORECAST CONFIDENCE MEDIUM

UPPER FLOW REMAINS CYCLONIC. 850 MILLIBAR COLD POOL EASES A BIT
INTO THE AFTERNOON. THINK STILL ENOUGH COLD AIR ALOFT TO GENERATE
CU LIKE WHAT IS GOING ON FURTHER WEST TODAY. 00Z ECMWF GENERATED
LIGHT QPF IN THE SE THOUGH AN OUTLIER AND SEEMS OVERDONE GIVEN
OVERALL LACK OF DEPTH TO ANY INSTABILITY AND DRY COLUMN. 925 TEMPS
REBOUND TO 3-5C DURING THE AFTERNOON SO 50 TO 55 LOOKS GOOD FOR
THE CWA.

SUNDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH

A POLAR HIGH PRESSURE RIDGE WILL SETTLE OVER WI SUN NT AND MON AM AS
THE DEPARTING UPPER LOW MOVES NEWD ACROSS QUEBEC CANADA AND THE
WRN UPPER RIDGE MOVES OVER THE HIGH PLAINS. GOOD RADIATIONAL
COOLING CONDITIONS WILL RESULT IN WIDESPREAD FROST WITH FORECASTED
LOW TEMPS IN THE LOWER 30S...MID 30S NEAR THE LAKE. A FROST
ADVISORY WILL LIKELY BE NEEDED FOR ALL OF SRN WI FOR EARLY MON
AM.

A STRONG SHORTWAVE TROUGH AND ASSOCIATED SFC LOW WILL RIDE EWD
ALONG THE US/CANADIAN BORDER...THEREBY FLATTENING THE UPPER RIDGE
FOR MON AND TUE. THE SFC HIGH WILL SHIFT EAST OF WI DURING THE
DAY ON MON WITH SLY WINDS DEVELOPING AND MILDER TEMPS. THE
MODELS INDICATE A STRONG 700 MB BAROCLINIC ZONE VIA WARM ADVECTION
AND FRONTOGENESIS FOR MONDAY AFTERNOON AND NIGHT. FORECAST
SOUNDINGS STILL SATURATE DOWN TO NEARLY 800 MB DURING THIS TIME
AND TYPICALLY THIS SCENARIO DOES RESULT IN AT LEAST SOME PCPN.
THEREFORE CONTINUED TO GO WETTER THAN THE MODELS OR MOS GUIDANCE
WITH CHANCE POPS FORECAST. AS THE MID LEVEL WARM ADVECTION AND
MOISTURE MOVES EWD...STRONG SFC-850 MB WARM ADVECTION WILL ENSUE
THROUGH TUE...HOWEVER VERY WARM AND DRY AIR IN THE MID LEVELS WILL
CAP THE ATMOSPHERE. A CONSENSUS OF 925 MB TEMPS YIELDS HIGH TEMPS
IN THE LOWER TO MID 80S OVER SOUTH CENTRAL WI WITH MUCH COOLER
TEMPS IN FAR ERN WI VIA A LAKE BREEZE.


.LONG TERM...

TUESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM

A TRAILING COLD FRONT FROM THE OCCLUDED LOW MOVING EWD ACROSS
MANITOBA AND ONTARIO CANADA WILL MOVE ACROSS SRN WI TUE NT AND
WED. CONVECTIVE INITIATION IS IN QUESTION DUE TO THE LACK OF
DYNAMICS WITH THE FRONT...POOR TIMING...AND THE STRONG CAPPING
THAT IS INITIALLY IN PLACE. THE FRONT IS THEN EXPECTED TO STALL
THROUGH FRIDAY BUT LIKELY OVER IL. IT IS HOWEVER SUFFICIENTLY
CLOSE TO MAINTAIN LOW POPS FOR THUNDER FOR MUCH OF THE WEEK.
1000-500 MB THICKNESSES WILL AVERAGE 560-564 DM FOR THE WEEK WITH
SUMMER LIKE TEMPS CONTINUING.

A SLOW MOVING UPPER TROUGH WILL THEN BECOME ESTABLISHED OVER THE
WRN USA LATE IN THE WEEK AND APPROACH THE ROCKIES. CYCLOGENESIS
WILL ENSUE OVER THE HIGH PLAINS ON FRI WITH A N-S TROUGH OF LOW
PRESSURE MOVING EWD ACROSS THE PLAINS FOR THE WEEKEND. THUNDER
CHANCES WILL INCREASE FOR THE WEEKEND AS THE WARM FRONT
APPROACHES.

&&

.AVIATION/00Z TAFS/...UPPER FLOW STRONGLY CYCLONIC WITH 500 MILLIBAR
TEMPS -20 TO -23C. VFR CU/ISOLAD SHRA WILL DISSIPATE WITH LOSS OF
HEATING. NW WINDS WILL REMAIN GUSTY 20-30 KNOTS INTO THIS EVENING
THEN EASE A BIT. LIGHTER WIND REGIME SUNDAY AS GRADIENT RELAXES THOUGH
LINGERING COLD AIR ALOFT IN UPPER CYCLONIC FLOW SO POTENTIAL FOR
MORE CU.

&&

.MARINE...SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 18Z SUNDAY AS
SURFACE PRESSURE GRADIENT AND WINDS JUST OFF THE DECK WILL KEEP
NORTHWEST WINDS GUSTING AT OR ABOVE CRITERIA. WINDS MAY
DIMINISH FOR A TIME TONIGHT BELOW CRITERIA...BUT TIME PERIOD TOO
SHORT TO SEPARATE OUT INTO TWO DIFFERENT ADVISORIES.


&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CDT SUNDAY FOR LMZ643>646.

&&

$$

TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR
SUNDAY NIGHT THROUGH SATURDAY...GEHRING