Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
000
FXUS63 KMKX 232030
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
330 PM CDT SAT MAY 23 2015

.SHORT TERM...

.TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

AREA OF LIGHT REFLECTIVITY RETURNS OVER NORTHEAST IOWA CONTINUE TO
MOVE CLOSER TO THE WESTERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON. THESE ARE LIKELY SPRINKLES AT WORST...AS CLOUD BASES ARE
AROUND 12000 FEET ABOVE GROUND LEVEL. THESE WERE BRING DRIVEN BY 700
MB WARM AIR ADVECTION AND A WEAK 500 MB VORTICITY MAXIMUM. THESE
SPRINKLES MAY MAKE IT INTO THE FAR WESTERN COUNTIES LATE THIS
AFTERNOON...THOUGH MESOSCALE MODELS WEAKEN THEM BEFORE THEY GET
HERE. FOR NOW...WILL LEAVE OUT OF FORECAST...GIVEN THE DRY AIR IN
THE LOW LEVELS.

OTHERWISE...EXPECT MIDDLE TO HIGH CLOUDS TO GRADUALLY OVERSPREAD THE
AREA TONIGHT AND LINGER ON SUNDAY. QUIET WEATHER IS EXPECTED
TONIGHT...AS AIRMASS REMAINS DRY. LOWS SHOULD DROP INTO THE MID 50S
IN MOST AREAS...PER 925 MB TEMPERATURE FIELDS ON MODELS.

CONTINUED TO RAMP UP POPS SUNDAY...AS 850 MB WARM AIR ADVECTION AND
MOISTURE STREAM INTO THE REGION. THE WARM AIR ADVECTION AND MOISTURE
GET STRONG SUNDAY AFTERNOON...SO KEPT HIGHEST POPS FOR THIS PORTION
OF THE DAY. SOME LOW TO MID LEVEL FRONTOGENESIS RESPONSE ALSO MOVE
NORTHWARD INTO THE AREA DURING THE AFTERNOON.

AREA FORECAST SOUNDINGS WERE SHOWING MAINLY MOIST ADIABATIC PROFILES
WITH VERY WEAK MEAN LAYER CAPE. THUS...HAVE ONLY SLIGHT CHANCES FOR
THUNDER. SOME DRYNESS IN THE LOW LEVELS WERE ALSO NOTED...ESPECIALLY
TOWARD FAR SOUTHEAST WISCONSIN. SO...THIS AREA MAY SEE MORE
SCATTERED PRECIPITATION THAN TO THE NORTHWEST. HIGHS WILL BE COOLER
WITH THE CLOUDS AND SOME PRECIPITATION...IN THE LOWER TO MID 70S
INLAND...60S LAKESIDE.

SUNDAY NIGHT THROUGH MEMORIAL DAY...FORECAST CONFIDENCE MEDIUM.

MID TO UPPER LEVEL RIDGING WILL BE IN PLACE SUNDAY NIGHT AS THE
LOW LEVEL FLOW BEGINS TO INCREASE OUT OF THE SOUTH IN THE WARM
SECTOR OF A LOW PRESSURE SYSTEM CENTERED IN THE CENTRAL PLAINS.
THE INCREASE IN LOW LEVEL MOISTURE TRANSPORT SHOULD AID IN THE
DEVELOPMENT OF SOME EVENING/OVERNIGHT CONVECTION THROUGH
INSTABILITY IS RATHER WEAK GIVEN THE WARM AIR ALOFT IN THE
MID/UPPER LEVELS. THERE COULD BE A BRIEF BREAK IN THE
PRECIPITATION SUNDAY EVENING...BUT SOME OF THE 23.12Z GUIDANCE
APPEARS TO BE SLOWING DOWN THE NORTHWARD ADVANCEMENT OF THE
SURFACE WARM FRONT AND THE RAIN ASSOCIATED WITH IT.

THE DEEPER FORCING WILL MOVE IN OVERNIGHT ON INTO THE MORNING OF
MEMORIAL DAY AS A MID LEVEL SHORT WAVE TROUGH PROPAGATES NORTHWARD
FROM THE SOUTHERN PLAINS INTO THE UPPER GREAT LAKES. INSTABILITY
LOOKS TO BE LOW AT ABOUT 50-150 J/KG...SO LIGHTNING SHOULD NOT BE
VERY FREQUENT WITH ANY SEVERE POTENTIAL ON THE LOW SIDE AS WELL.

AS THE LOW PRESSURE SYSTEM LIFTS NORTHWARD TOWARD LAKE
SUPERIOR...DRIER AIR WILL GET PULLED IN FROM THE SOUTHWEST AND
SHOULD HELP TO KEEP THINGS DRY MEMORIAL DAY AFTERNOON. THE
COMBINATION OF DRY AIR THROUGH THE COLUMN AND A TIGHTENING
PRESSURE GRADIENT WILL LEAD TO SOME GUSTY CONDITIONS.

.LONG TERM...

TUESDAY INTO TUESDAY NIGHT...FORECAST CONFIDENCE LOW.

THE MORE INTERESTING DAY COULD END UP BEING TUESDAY AS THE 23.12Z
NAM/GFS/ECMWF ALL SHOW A MID LEVEL SHORTWAVE TROUGH AND SURFACE
LOW COMING THROUGH IN THE AFTERNOON. THE QUESTION WILL BE WITH HOW
MUCH INSTABILITY WILL DEVELOP AND HOW POTENT THE MID LEVEL TROUGH
WILL BE SINCE THE 23.12Z NAM/ECMWF SHOW A WEAKER...POSITIVELY
TILTED TROUGH WHILE THE 23.12Z GFS20 HAS A NEGATIVELY TILTED AND
ALMOST CLOSED OFF TROUGH COMING THROUGH. 23.12Z NAM/GFS SOUNDINGS
SHOW FAIRLY UNIDIRECTIONAL FLOW THOUGH THERE IS SOME INCREASE IN
SPEED WITH HEIGHT.

WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE LOW.

THE SYSTEM WILL BE DEPARTING THE REGION WEDNESDAY THOUGH AN
INVERTED SURFACE TROUGH/TRAILING MID LEVEL SHORT WAVE TROUGH MAY
BE ENOUGH TO DEVELOP SOME SHOWERS. HIGH PRESSURE SHOULD MOVE
THROUGH ON THURSDAY BEFORE THE NEXT ROUND OF POTENTIAL RAIN MOVES
IN AHEAD OF THE NEXT SYSTEM/COLD FRONT THURSDAY NIGHT INTO FRIDAY.
GIVEN THE ALMOST ZONAL WEST-SOUTHWESTERLY FLOW...GETTING THE
TIMING DOWN OF ANY SYSTEM THIS FAR OUT WILL BE DIFFICULT.

&&

.AVIATION/00Z TAFS/...

VFR CONDITIONS ARE EXPECTED TONIGHT AND MOST OF SUNDAY ACROSS TAF
SITES. MIDDLE TO HIGH CLOUDS WILL GRADUALLY SPREAD NORTHEAST INTO
THE AREA TONIGHT...REMAINING CLOUDY ON SUNDAY. SOUTHEAST LAKE BREEZE
WILL REMAIN UNTIL EARLY EVENING AT EASTERN SITES...WITH LIGHT SOUTH
WINDS AT MADISON. WINDS WILL GRADUALLY BECOME SOUTHEAST TONIGHT INTO
SUNDAY...INCREASING IN SPEED DURING THE AFTERNOON.

MAIN AREA OF SHOWERS SHOULD MOVE NORTHWARD INTO MADISON BY MIDDAY
SUNDAY...AND THE EASTERN SITES BY MID AFTERNOON SUNDAY. THIS
ACTIVITY WILL BE MORE SCATTERED TOWARD THE EASTERN SITES THAN AT
MADISON. WILL NOT MENTION THUNDER IN TAFS SUNDAY...AS RISK IS LOW
WITH FAIRLY STABLE AIRMASS IN PLACE. MAY SEE MVFR CATEGORY CEILINGS
AND VISIBILITIES DEVELOP WITH THE SHOWERS AT TIMES...BUT LEFT OUT OF
TAFS FOR NOW.

&&

.MARINE...

GUSTY SOUTHWEST WINDS  ARE EXPECTED TO DEVELOP ON SUNDAY ACROSS THE
NEARSHORE WATERS OF LAKE MICHIGAN...AS A TIGHT PRESSURE GRADIENT
DEVELOPS WITH LOW PRESSURE MOVING INTO THE REGION. FREQUENT GUSTS OF
25 TO 30 KNOTS ARE POSSIBLE...PERHAPS LINGERING INTO SUNDAY EVENING.
A SMALL CRAFT ADVISORY MAY BE NEEDED FOR THIS PERIOD.

&&

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

$$

TONIGHT/SUNDAY AND AVIATION/MARINE...08/WOOD
SUNDAY NIGHT THROUGH SATURDAY...HALBACH


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.