Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 182103
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
403 PM CDT MON AUG 18 2014

.TONIGHT AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM.

MAINLY ELEVATED CONVECTION DEVELOPING OVER NORTHWEST...WEST CENTRAL
AND CENTRAL WISCONSIN...WITHIN 850 MB WARM AIR ADVECTION AND LOW
LEVEL JET AXIS. THIS SHOULD REMAIN MAINLY NORTH OF THE AREA. MORE
CONVECTION DEVELOPING NEAR LA CROSSE INTO SOUTHEAST MINNESOTA AND
FAR NORTHEAST IOWA. THIS AREA WAS MORE SURFACE BASED AND TRYING TO
DEVELOP ON SURFACE CONFLUENCE ZONE IN THAT GENERAL AREA...ALONG WITH
HELP FROM APPROACHING 500 MB VORTICITY MAXIMUM FROM SOUTH CENTRAL
MINNESOTA.

LATEST MESOSCALE MODELS CONTINUE TO DEVELOP SCATTERED TO NUMEROUS
STORMS ACROSS AND JUST WEST OF THE AREA INTO LATE AFTERNOON...MOVING
EAST ACROSS THE AREA INTO EARLY THIS EVENING. THIS WOULD BE
ASSOCIATED WITH A WEAK LEAD 500 MB VORTICITY MAXIMUM AND WEAK
SURFACE BOUNDARIES. THEY THEN TRY TO BRING A BROKEN LINE OF
CONVECTION EAST THROUGH THE AREA DURING THE LATE EVENING AND
OVERNIGHT HOURS...ASSOCIATED WITH BETTER DEFINED 500 MB VORTICITY
MAXIMUM FROM SOUTH CENTRAL MINNESOTA...AND SURFACE CONFLUENT ZONE.

AREA FORECAST SOUNDINGS SHOWING NO CAPPING WITH 1000 TO 1500 J/KG OF
MEAN LAYER CAPES DEVELOPING INTO THE EARLY EVENING...BEFORE DROPPING
SOMEWHAT LATER TONIGHT...AND INCREASING AGAIN ON TUESDAY. DEEP LAYER
SHEAR IS 20 TO 25 KNOTS INTO THIS EVENING AND OVERNIGHT...AND 25 TO
30 KNOTS ON TUESDAY. NAM CWASP MORE AGGRESSIVE WITH SEVERE RISK THAN
GFS CWASP FOR TONIGHT.

SPC HAS AREA WEST OF A RIPON...TO WHITEWATER...TO BELOIT LINE IN A
SLIGHT RISK FOR SEVERE STORMS INTO THIS EVENING. MAY BE TOUGH TO SEE
WIDESPREAD SEVERE STORMS TONIGHT...WITH MODEST DEEP LAYER
SHEAR...LACK OF WELL DEFINED LOW LEVEL BOUNDARY AND RELATIVELY SLOW
STORM MOTIONS. GIVEN CAPE/SHEAR COMBINATION...COULD SEE AN ISOLATED
SEVERE HAIL OR WIND GUST EVENT WITH THE STRONGEST STORMS.

TIMED FIRST BATCH OF STORMS EAST THROUGH THE AREA INTO EARLY THIS
EVENING...WITH SECOND BATCH LATER THIS EVENING INTO THE OVERNIGHT
HOURS. SLOW STORM MOTION VECTORS WITH PRECIPITABLE WATER VALUES
AROUND 1.80 INCHES SUGGEST HEAVY RAINFALL IS POSSIBLE WITH THE STORMS
DURING THIS TIME. THIS CERTAINLY WOULD BE WELCOME ACROSS THE AREA.

KEPT SCATTERED/NUMEROUS POPS IN FOR TUESDAY...HIGHEST IN THE
NORTHEASTERN COUNTIES...AS 500 MB SHORTWAVE TROUGH IS SLOW TO EXIT
THE REGION. WARM AND HUMID CONDITIONS WILL LINGER TONIGHT AND
TUESDAY. ADDED PATCHY FOG LATER TONIGHT WITH MOIST AIRMASS IN PLACE
AND RELATIVELY LIGHT WINDS.

.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY NIGHT.

TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE HIGH

WILL KEEP SMALL CHANCE POPS IN THE EASTERN PORTION OF CWA TUESDAY
EVENING UNTIL SHORT WAVE AND ATTENDANT WEAK SURFACE LOW PUSH FAR
ENOUGH TO THE EAST/NORTHEAST FOR THE SUBSIDENCE IN THE NEGATIVE
VORTICITY ADVECTION BEHIND THE WAVE TO OVERSPREAD ALL OF SRN WI
BY...OR SHORTLY AFTER...06Z WEDNESDAY.

WEAK SURFACE HIGH UNDER SHORT WAVE RIDGING THEN KEEPS CWA DRY
THROUGH WEDNESDAY UNTIL WEDNESDAY NIGHT. MINIMAL COLD AIR ADVECTION
AS SOUTHERN EDGE OF 850 MB COLD POOL GRAZES FORECAST AREA...WITH 850
MB TEMPS MODIFYING UPWARD THROUGH THE DAY AS WINDS BACK FROM NW TO
WEST.

WEDNESDAY NIGHT...FORECAST CONFIDENCE MEDIUM

WHILE FRONTOGENETIC RESPONSE IN THE 850 MB-700 MB LAYER TO WARM AIR
ADVECTION BEGINS TO INCREASE BY 00Z THURSDAY OVER SW WISCONSIN...
WILL TAKE SOME TIME FOR MOISTURE ADVECTION TO SATURATE THE COLUMN
SUFFICIENTLY FOR PCPN TO REACH THE SURFACE. WILL HAVE CHANCE POPS IN
THE SW CWA IN THE EVENING...THEN LIKELY AS FORCING INCREASES WITH
FOCUSED WARM AIR ADVECTION AS LLJ INCREASES TO 25 TO 30 KNOTS AFTER
06Z.

THURSDAY AND THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

BAND OF WAA SHOWERS AND STORMS WILL LIFT ACROSS CWA WITH 850 MB
BAROCLINIC ZONE AND SURFACE WARM FRONT THAT BISECTS THE CWA FROM NW
TO SE BY 00Z FRIDAY. FRONTOGENETIC FORCING AND Q-VECTOR CONVERGENCE
WEAKEN THROUGH THE DAY WITH WEAKENING WINDS BEHIND THE BAROCLINIC
ZONE AS IT LIFTS NE...THEN CHANCES INCREASE IN THE LATE AFTERNOON
AND EVENING WITH APPROACH OF SURFACE TROUGH. VARIED TIMING OF LOW
LEADS TO A BROAD BRUSH CHANCE FOR NOW.

.LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE LOW

THE VARIED TIMING AND STRENGTH OF 500 MB TROUGH LEADING TO VARYING
SOLUTIONS TO PCPN TIMING WITH SURFACE LOW ACROSS REGION LATE WEEK
INTO EARLY WEEKEND...AND SUBSEQUENT TRAILING WAVE/TROUGH FOR SUNDAY
MONDAY. AGAIN BROAD-BRUSHED CHANCE/SLIGHT CHANCE POPS THROUGH THE
WEEKEND. AMPLIFIED PATTERN LEADING TO OVERALL WARM MOIST SWLY
FLOW.

&&

.AVIATION/00Z TAFS/...

FIRST BATCH OF SHOWERS AND STORMS WITH MVFR CEILINGS AND
VISIBILITIES WILL REACH MADISON AROUND 00Z TUESDAY...AND THE EASTERN
SITES BY 02Z TUESDAY. A SECOND BATCH WILL REACH MADISON AROUND 04Z
TUESDAY...AND THE EASTERN SITES AROUND 06Z TUESDAY. THEY WILL BE ON
AND OFF TONIGHT INTO TUESDAY MORNING.

SHOULD SEE SOME IFR CEILINGS AND VISIBILITIES LATER TONIGHT INTO
TUESDAY MORNING...AS WINDS BECOME SOMEWHAT LIGHT WITH LINGERING
MOISTURE AND PRECIPITATION. COULD SEE SMALL HAIL AND BRIEF GUSTY
WINDS WITHIN STRONGEST STORMS THIS EVENING.

SOUTH WINDS SHOULD PICK UP AND BECOME SOUTHWEST ON
TUESDAY...SHIFTING WEST TUESDAY AFTERNOON AS SURFACE BOUNDARY
CROSSES THE AREA. SHOWERS AND STORMS REMAIN POSSIBLE TUESDAY
AFTERNOON...BUT WILL NOT MENTION IN TAFS AT THIS TIME DUE TO
UNCERTAINTY IN AREAL COVERAGE.

&&

.MARINE...

SHOULD SEE PATCHY FOG DEVELOP ACROSS THE NEARSHORE WATERS OF LAKE
MICHIGAN TONIGHT...AS MORE MOISTURE MOVES INTO THE AREA AND OVER THE
LAKE. NOT ANTICIPATING DENSE FOG AT THIS TIME...THOUGH IS MAY BE
POSSIBLE IF WINDS BECOME LIGHT ENOUGH.

&&

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

$$

TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...REM


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