Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 221637
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1037 AM CST MON DEC 22 2014

.AVIATION/18Z TAFS/...EXPECTING MVFR AND EVEN SOME VFR CIGS TO
LOWER AS WIDESPREAD PRECIP LIFTS NORTH FROM ILLINOIS. SREF CIG
PROG SHOWS THIS HAPPENING BETWEEN 21-02Z. GFS/NAM MOS IN DECENT
AGREEMENT WITH THESE LOWER CIGS. VSBYS WILL BE DOWN IFR LEVELS.
SHORTWAVE ENERGY PIVOTS INTO SRN WI LATER TONIGHT AFTER INITIAL
WAVE ARRIVES TOWARDS 00Z. SURFACE LOW OCCLUDES WITH BAGGY PRESSURE
GRADIENT AND WIND FIELD EVOLVING TUESDAY. PRECIP TYPE EXPECTED TO
BE RAIN FOR MUCH OF THIS EVENT WITH ANY BRIEF SNOW POTENTIAL ON
LEADING EDGE OF PRECIP SHIELD AS IT ADVANCES NORTH INTO SRN WI.
IMPROVEMENT NOTED LATER TUESDAY AS DRY SLOT WORKS IN. PRECIP LIFTS
NORTH WITH SOME IMPROVEMENT IN VSBYS AND CIG HGTS.

PC

&&

.PREV DISCUSSION... /ISSUED 424 AM CST MON DEC 22 2014/

SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.

SCT RAIN AND SNOW SHOWERS MOVING NWD ACROSS THE AREA WITH PCPN TYPE
MORE RAIN NEAR THE IL BORDER. THE PCPN WILL REMAIN SPOTTY INTO THE
EARLY AFTERNOON WHILE THE 925 MB 0C ISOTHERM WILL GRADUALLY SHIFT
NWD THROUGH SRN WI. THE UPPER TROUGH OVER THE CENTRAL USA WILL
CONTINUE TO DEEPEN TODAY AND TNT AS SHORTWAVE TROUGHS DIG INTO THAT
REGION FROM THE ROCKIES. CYCLOGENESIS WILL QUICKLY EVOLVE TO
OCCLUSION FROM MO INTO ERN IA AND NRN IL FOR TNT. THE NOSE OF THE
LLJ AND ASSOCIATED THETAE ADVECTION AND FRONTOGENESIS...AIDED BY
INCREASING PVA ALOFT WILL BRING WIDESPREAD PCPN FROM SOUTH TO NORTH
FROM MID TO LATE AFTERNOON. THIS PCPN SHOULD START AS ALL RAIN IN
THE SRN CWA AND WILL EITHER BE A MIXTURE OR BRIEFLY STARTING AS SNOW
IN THE NORTH. LGT TO MDT RAINFALL IS THEN EXPECTED MUCH OF THE NIGHT
WITH THE DRY SLOT MOVING INTO SE WI BY 12Z TUE.

TUESDAY THROUGH CHRISTMAS DAY... FORECAST CONFIDENCE MEDIUM.

SURFACE LOW PRESSURE WILL TRACK FROM NORTHEAST IOWA TO NORTHEAST
WISCONSIN DURING THE DAY TUESDAY AND WEAKEN OVERNIGHT AS IT DRIFTS
INTO EASTERN ONTARIO. THIS IS IN RESPONSE TO THE MIDWEST 500MB
CLOSED UPPER LOW WEAKENING AND LIFTING NORTHEAST. SOUTHEAST
WISCONSIN WILL END UP IN THE DRY SLOT FOR THE DAY ON TUESDAY. THIS
MEANS MID LEVELS WILL DRY OUT AND LOW LEVELS WILL REMAIN MOIST... SO
WE CAN GENERALLY EXPECT CLOUDY SKIES WITH PERIODS OF DRIZZLE AND
FOG.

A SECONDARY UPPER LOW WILL DEVELOP AT THE BASE OF THE ELONGATED
TROUGH OVER THE AR/MO AREA ON WEDNESDAY AND TRACK NORTHEAST THROUGH
LOWER MICHIGAN WED EVENING. A 150 KT UPPER JET STREAK WILL LEAD TO
SURFACE CYCLOGENESIS OVER THE EASTERN GREAT LAKES. SOUTHEAST WI WILL
BE ON THE FAR WESTERN PERIPHERY OF THIS SYSTEM. I LOWERED THE PRECIP
CHANCES TO SLIGHT CHANCE FOR WED AND WED NIGHT AND WINDS SHOULD NOT
EVEN BE VERY STRONG EXCEPT FOR OVER LAKE MICHIGAN.

925MB TEMPS WILL FALL BELOW 0C IN SOUTHEAST WI TUE EVENING BUT WILL
REMAIN WARMER THAN -5C THROUGH WED NIGHT. WE WILL BE HOVERING AROUND
THE FREEZING MARK AT THE SURFACE... SO THIS WILL MEAN A RAIN OR SNOW
MIX FOR ANY LIGHT PRECIP WE GET.

MID LEVEL RIDGING WILL ALLOW FOR QUIET WEATHER IN SOUTHERN
WI CHRISTMAS DAY.

LONG TERM...

FRIDAY THROUGH SATURDAY... FORECAST CONFIDENCE MEDIUM.

SURFACE LOW PRESSURE... IN RESPONSE TO A DIGGING UPPER TROUGH OVER
THE INTERMOUNTAIN WEST... WILL DEVELOP IN THE CENTRAL PLAINS THU
NIGHT AND TRACK NORTHEAST ACROSS SOUTHERN WI FRI AFTERNOON/EVENING.
MODELS ARE NOW SHOWING SOUTHERN WI IN THE DRY AREA FOR FRIDAY WITH A
CHANCE OF LIGHT SNOW FRIDAY NIGHT WITH THE COLD FRONT. SURFACE HIGH
PRESSURE AND DRY WEATHER WILL DOMINATE FOR THE WEEKEND INTO
MONDAY... BUT TEMPERATURES WILL BE BELOW AVERAGE.

AVIATION/12Z TAFS/...SCT RAIN AND SNOW SHOWERS WILL CONTINUE INTO
THE EARLY AFTERNOON WITH 3-5SM VSBYS IN SOME OF THE SHOWERS. LOW
PRESSURE WILL DEVELOP OVER THE GREAT PLAINS TODAY AND MOVE INTO SW
WI TUE AM. WIDESPREAD RAIN WILL MOVE NWD INTO SRN WI THIS AFTERNOON
WITH LGT TO MDT RAIN ALL NIGHT. SOME FOG WILL ALSO DEVELOP
ESPECIALLY TUE AM WHEN THE LOW MOVES ACROSS THE AREA.

CIGS OF 1-3 KFT AT KMSN AND KUES WILL TRANSITION TO 3.5-5.0 KFT BY
14-15Z WITH VSBYS MAINLY STAYING ABOVE 5SM. KMKE AND KENW WILL
CONTINUE TO SEE VFR CIGS THIS AM AS WELL WITH VSBYS AROUND 5-6SM AT
KENW THIS AM. WHEN THE WIDESPREAD RAIN ARRIVES BY THE MIDDLE OF THE
AFTERNOON THE CIGS WILL FALL BACK TO 1.0-3.0 KFT AND EVENTUALLY
BELOW 1KFT TNT. THE VSBYS WILL ALSO DROP WITH THE RAIN AND ANY FOG
FROM 3-5SM THIS AFTERNOON TO 1-2SM FOR TNT BUT LOCALLY LOWER VSBYS
ARE POSSIBLE. THE BETTER CHANCES FOR FOG AND VERY LOW VSBYS WILL BE
TUE AM.

MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT TODAY AND TNT FOR
BREEZY ESELY WINDS AND HIGH WAVES AS LOW PRESSURE OVER THE GREAT
PLAINS STRENGTHENS AND MOVES TO ERN IA BY 12Z TUE. SUBSIDING WINDS
AND WAVES ARE EXPECTED ON TUE AND TUE NT AS THE LOW WEAKENS NEWD
ACROSS WI.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 9 AM CST TUESDAY FOR LMZ643>646.

&&

$$
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
TUESDAY THROUGH SUNDAY...MRC


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