Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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240
FXUS63 KMKX 040300
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
900 PM CST WED FEB 3 2016

.UPDATE...

NO BIG CHANGES THIS EVENING. SHORT WAVE RIDGING ARRIVES LATE
TONIGHT AND IS ALREADY STARTING TO PUSH THE BACK EDGE OF THE LOWER
CLOUDS EAST INTO THE WESTERN FORECAST AREA. THAT TREND SHOULD
CONTINUE OVERNIGHT. THE CLEAR SKIES AND LIGHT WINDS WILL ALLOW
TEMPS TO TAKE...ESPECIALLY RIGHT BEFORE SUNRISE.

&&

.AVIATION/06Z TAFS/...

THE BACK EDGE...CLEARING LINE...OF THE MVFR CLOUD DECK CURRENTLY
OVER SOUTHERN WISCONSIN IS BEGINNING TO ENTER WESTERN SAUK...IOWA
AND LAFAYETTE COUNTIES WEST OF MADISON. THIS IS IN RESPONSE TO
HIGH PRESSURE RIDGING AND DRY AIR WORKING IN. KMSN SHOULD SEE
CLEARING SKIES BETWEEN 06-07Z THU AND MAY TAKE UNTIL ABOUT 12Z THU
TO REACH KMKE/KUES/KENW. LOOK FOR VFR CONDITIONS IN THE WAKE OF
THE CLEARING. A WEAK TROUGH OF LOW PRESSURE APPROACHING FROM THE
NORTHWEST COULD BRING ANOTHER ROUND OF MVFR CIGS TO KMSN AFTER
ABOUT 22Z THU...CONTINUING FOR A TIME INTO THE EVENING...ALONG
WITH A CHANCE OF SOME LIGHT SNOW. ANY ACCUMS LIKELY WILL BE LESS
THAN 1/4 INCH...DUSTING STUFF. IT MAY NOT EVEN MAKE IT TO
KMKE/KUES/KENW BEFORE IT WEAKENS AND EVAPORATES.


&&

.PREV DISCUSSION... /ISSUED 328 PM CST WED FEB 3 2016/

TONIGHT AND THURSDAY... FORECAST CONFIDENCE HIGH.

LIGHT SNOW SHOWERS ASSOCIATED WITH A WEAK VORTICITY MAX ROUNDING THE
BASE OF THE 500MB TROUGH WILL MOVE OUT OF THE AREA BY THIS EVENING.
SATELLITE IMAGERY SHOWS CLEAR SKIES OVER SOUTHEAST WI. THAT CLEARING
LINE IS STEADILY MOVING EAST THIS AFTERNOON AND LINES UP WELL WITH
THE 850-500MB LOWER RH VALUES ON MODELS. IF THE LINEAR TREND
CONTINUES... MADISON WOULD BE CLEAR BY 6 PM. IF THE RH PROG IS MORE
ACCURATE... THEN MADISON WOULD NOT CLEAR UNTIL 4 AM. OPTED FOR THE
SLOWER CLEARING ACROSS SOUTHERN WI.

ONCE SKIES CLEAR... TEMPERATURES WILL DROP OFF QUICKLY TONIGHT. WITH
THE COLDEST AIR ALOFT OVER US AT MIDNIGHT AND THE CLEARING SKIES...
EXPECT TEMPS TO BOTTOM OUT IN THE SINGLE DIGITS AND LOWER TEENS.

SURFACE RIDGING WILL BRING LIGHT WEST WINDS IN THE MORNING. A 500MB
TROUGH WITH WEAK VORTICITY ADVECTION WILL BRING LIGHT SNOW TO
CENTRAL WI DURING THE AFTERNOON AND EVENING. ARRIVAL TIME LOOKS LIKE
LATE THU AFTERNOON NORTHWEST OF MADISON.

FRIDAY AND FRIDAY NIGHT - CONFIDENCE...MEDIUM
SURFACE RIDGE WILL BE IN PLACE ACROSS THE AREA. MID LEVEL RIDGING
SHIFTS INTO THE OH VLY AS UPSTREAM POSITIVE TILT TROUGH RIDES
SOUTHEAST FROM THE DAKOTAS INTO IOWA. FORCING LOOKS WEAK THROUGH
00Z WITH RESPECT TO WAA AND DCVA CONSIDERATIONS. THERE IS SOME
UPTICK IN FORCING AFTER 00Z. HOWEVER CONSENSUS OF PROGS IS TO TAKE
BETTER 500 VORT TO OUR SOUTHWEST THOUGH TROUGH AXIS SLIDES ACROSS.
SO WILL LEAVE PRECIP OUT OF FORECAST THROUGH 00Z. THE LOW LEVEL
TROUGH AND 500 MILLIBAR TROUGH ARRIVE FRIDAY NIGHT. QPF IS MEAGER.
BUFKIT SOUNDINGS DO SHOW CONSIDERABLE DRY AIR IN THE 950/700
MILLIBAR LAYER BUT THIS LAYER GRADUALLY SATURATES WITH TIME AS THE
NIGHT WEARS ON. Q-VECTOR CONVERGENCE IS NOT OVERLY IMPRESSIVE BUT
WILL HAVE SMALL POPS OR FLURRIES. IF MODELS BECOME A BIT MORE
ROBUST ON FORCING THEN POPS WILL NEED TO BE BOOSTED OVER THE GOING
COLLABORATED FORECAST.

SATURDAY - CONFIDENCE...MEDIUM
TROUGH SHIFTS EAST OF THE AREA EARLY IN THE DAY. LLVL RH PROGS
SHOW QUITE A BIT OF LINGERING MOISTURE WITH WEAK WAA CONTINUING IN
THE WAKE OF THE TROUGH. SO BUFKIT DOES SHOW SOME POTENTIAL FOR A
WEAKER INVERSION TO HOLD IN THE CLOUD COVER.

SUNDAY - CONFIDENCE...MEDIUM
THE WAA REGIME WILL STRENGTHEN AHEAD OF A STRONGER MID/UPPER
LEVEL TROUGH CARVING OUT ACROSS THE MID SECTION OF THE COUNTRY.
THE GFS CONTINUES TO BE FASTER WITH THE LEAD PIECE OF ENERGY
PIVOTING INTO WI. THE GEM AND ECMWF ARE SHOWING MORE A SLOWER
SOLUTION WITH ANY DCVA REMAINING LARGELY WEST OF THE AREA.

MONDAY THROUGH WEDNESDAY - CONFIDENCE...MEDIUM
WHILE STILL SOME DETAILS TO IRON OUT THE MAIN MESSAGE IS COLD
TROUGH SETTING UP ACROSS THE GREAT LAKES. BIG DIFFERENCES BETWEEN
THE GFS AND ECMWF 925 TEMPS WITH THE GFS PUSHING -20C TUESDAY AND
WEDNESDAY AND THE ECMWF CLOSER TO -10C. SUPERBLEND THROWING OUT
QUITE A BIT OF CHANCY POPS AND IN THIS REGIME WITH CYCLONIC FLOW
AND EMBEDDED VORT MAXES...SEEMS REASONABLE SO WILL NOT DEVIATE AT
THIS TIME. THE GFS MOVES THE UPPER TROUGH SOUTHEAST OF THE REGION
TUE NGT AND WED THOUGH THE ECMWF BRINGS ANOTHER REINFORCING
SHORTWAVE THROUGH ON WEDNESDAY. THE GFS HAS THIS FEATURE ARRIVING
HERE BEYOND THIS PERIOD BUT WELL WEST OF THE PRIMARY TROUGH AXIS
WHICH WILL ALREADY BE NEAR THE EASTERN SEABOARD.

AVIATION/00Z TAFS/...THERE IS A BACK EDGE TO THE MVFR STRATUS SHIELD
OVER WESTERN WI THIS AFTERNOON. EXPECT CLEARING FROM WEST TO EAST
FROM LATE EVENING THROUGH LATE TONIGHT.

THERE IS A CHANCE FOR LIGHT SNOW MAINLY NORTH OF MSN TO MKE LATE THU
AFTERNOON THROUGH THE EVENING.

MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT UNTIL 9 PM TONIGHT FOR
NORTHWEST WINDS OF 15 TO 20 KNOTS AND GUSTS TO 25 KNOTS. WINDS WILL
DIMINISH OVERNIGHT AS A WEAK RIDGE OF HIGH PRESSURE BUILDS OVER THE
NEARSHORE WATERS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

UPDATE...DAVIS
TONIGHT/THURSDAY AND AVIATION/MARINE...MRC
THURSDAY NIGHT THROUGH WEDNESDAY...COLLAR



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