Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 290841
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
341 AM CDT FRI AUG 29 2014

.TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.

INFLUENCE OF DRY SOUTHEAST FLOW AROUND WESTERN FLANK OF DEPARTING
HIGH PRESSURE EVIDENT IN TIGHT SURFACE DEW POINT GRADIENT THAT
REMAINS ALONG IL/WI BORDER AND THE MS RIVER VALLEY.

SHOWERS ACROSS CENTRAL/NE WI IN REGION OF 850 MB FRONTOGENETIC
RESPONSE TO 20-30 KT WINDS ACROSS EAST-WEST 850 MB BAROCLINIC ZONE
BISECTING THE STATE.

MCV-DRIVEN POCKET OF SHOWERS/THUNDERSTORMS IN NORTHEAST IOWA IS
WEAKENING AS IT LIFTS NE TOWARD SW WI AND INTO THE DRIER...MORE
STABLE AIR...WITH THE MCV SHEARING OUT/ WEAKENING AS IT MOVES INTO
THE MEAN RIDGE POSITION. HOWEVER MOISTURE TRANSPORT INTO STATE ON 30
KT 850 MB WINDS ALONG WITH ADDITIONAL FORCING FOR ASCENT FROM UPPER
LEVEL DIFFLUENCE/DIVERGENCE WILL BE ENOUGH TO SUPPORT THE SHOWERS
ACROSS THE NORTHWEST HALF OF THE FORECAST AREA THIS MORNING...WITH
SOME SCATTERED SHOWERS IN THE SOUTHEAST. A FEW RUMBLES OF THUNDER
ARE POSSIBLE.

MODELS INDICATE A BREAK IN THE PCPN LATE THIS MORNING INTO THIS
AFTERNOON. UPPER RIDGING SLOWLY MOVING EAST WITH APPROACHING TROUGH
OMEGA INCREASES AS LLJ STRENGTHENS LATE THIS AFTERNOON AND EVENING
AS MAIN 500 MB TROUGH MOVES INTO WRN WI BY 12Z SAT.

NORTHWEST HALF OF FORECAST AREA IN FAVORABLE AREA FOR HEAVY RAIN
TONIGHT AS CAPE IS TALL AND SKINNY WITH CORFIDI VECTORS HOVERING
AROUND 10KTS...WITH PRECIP WATER VALUES RISING FROM 1.6 TO 2 INCHES.
WPC HAS LOCATIONS NORTHWEST OF A PORT WASHINGTON...FORT ATKINSON TO
MONROE LINE ARE IN A SLIGHT RISK FOR RAINFALL TO EXCEED FLASH FLOOD
GUIDANCE.

HOWEVER...WITH PREVIOUS 24 HOURS MUCH DRIER THAN ORIGINALLY FORECAST
AND HIGHEST WPC-BASED QPF TOTALS THROUGH SATURDAY MORNING TO THE
NORTH AND WEST OF THE FORECAST AREA...WITH IN-CWA TOTALS BELOW THE
1 TO 6-HOUR FLASH FLOOD GUIDANCE BETWEEN 2 AND 3 INCHES...WILL
KEEP THE ESF STATEMENT GOING FOR LOCALIZED URBAN/SMALL STREAM
FLOODING POTENTIAL BUT NO FLASH FLOOD WATCH AT THIS TIME.

SPC HAS A 5 PCT CHANCE FOR WIND GUSTS WITH STEEP LOW-LEVEL LAPSE
RATES PRODUCING AN INVERTED V DRY ADIABATIC PROFILE UP TO 4K TO 5K
FT ON WESTERN CWA FORECAST SOUNDINGS LATE THIS AFTERNOON/EARLY
EVENING IF FORECAST CAPE VALUES CAN BE REALIZED.

.SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM

LATEST MODEL GUIDANCE SUGGEST THAT A SURFACE FRONTAL BOUNDARY AND
UPPER LEVEL SHORTWAVE AXIS WILL BE POSITIONED JUST TO THE WEST OF
THE FORECAST AREA SATURDAY MORNING. SHOWERS AND STORMS ARE LIKELY
AHEAD OF THESE DURING SATURDAY MORNING...WITH A CHANCE CONTINUING
INTO THE AFTERNOON AS THE TROUGH MOVES THROUGH AND THE FRONT
STALLS NEAR THE WI/IL BORDER.

ANOTHER SHORTWAVE WILL MOVE THROUGH SATURDAY EVENING AND
OVERNIGHT...BUT KEPT THE FORECAST DRY DUE TO MUCH DRIER AIR ALOFT.
SUNDAY THEN LOOKS LIKE A PLEASANT DAY IN BETWEEN LOW PRESSURE
SYSTEMS.

HIGH TEMPERATURES SATURDAY SHOULD BE RIGHT AROUND NORMAL...RISING
TO A COUPLE DEGREES ABOVE NORMAL FOR SUNDAY.

.MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE...MEDIUM

SHOWERS AND STORMS ARE LIKELY IN THE WEST BY DAYBREAK MONDAY
MORNING AND THEN ACROSS THE FORECAST AREA DURING THE DAY AS A
COLD FRONT MOVES THROUGH. SOME STRONGER STORMS ARE POSSIBLE
MONDAY...BUT THIS WILL BE DEPENDENT ON THE TIMING OF THE FRONT. IT
LOOKS LIKE A DECENT AMOUNT OF INSTABILITY TO GO ALONG WITH AROUND
40 KNOTS OF 0-6 KM BULK SHEAR. MODELS ARE HINTING AT THE FRONT
MOVING THROUGH EARLIER IN THE DAY THOUGH...WHICH WOULD LIMIT
THE TIME FOR DAYTIME HEATING AND RESULTANT DESTABILIZATION.

IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY WITH THE FRONTAL
BOUNDARY AND HIGHER MOISTURE/INSTABILITY REMAINING SOUTH.

A RETURN OF MOISTURE UNDER SOUTHERLY LOW LEVEL FLOW MAY BRING
SHOWERS AND STORMS BACK TO THE AREA FOR THURSDAY.

TEMPERATURES FOR THE MONDAY THROUGH THURSDAY TIME PERIOD SHOULD
REMAIN NEAR TO A COUPLE DEGREES ABOVE NORMAL.

&&

.AVIATION/12Z TAFS/...MARINE...BEACHES...THESE SECTIONS WILL BE
ADDED SHORTLY.

&&

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

$$

TODAY/TONIGHT AND AVIATION/MARINE/BEACHES...REM
SATURDAY THROUGH THURSDAY...DDV



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