474
FXUS63 KMKX 071719
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1219 PM CDT TUE JUL 7 2020
UPDATE
LOTS OF CUMULUS DEVELOPMENT ACROSS SOUTHERN WISCONSIN WITH A FEW
SHOWERS. NO MAJOR SOURCES OF FORCING APPARENT BUT WITH THE LAKE
BREEZE AND POTENTIALLY SOME FORCING PUSHING IN FROM THE WEST WE
MAY START TO SEE MORE DEVELOPMENT OVER THE NEXT FEW HOURS.
AVIATION(18Z TAFS)
SCATTERED 5 KFT CUMULUS ACROSS SOUTHERN WISCONSIN. WHILE GENERALLY
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY THUNDERSTORM/SHOWER
DEVELOPMENT IS POSSIBLE ACROSS THE REGION SO OVER THE NEXT FEW
HOURS THROUGH THE AFTERNOON EXPECT POTENTIAL FOR SOME SHOWERS AND
THUNDERSTORMS. SOME OF THESE THUNDERSTORMS COULD BECOME STRONG,
PRIMARILY FURTHER WEST BUT WILL BE ISOLATED TO SCATTERED. MFVR
VSBYS ARE POSSIBLE WITH ANY STORMS PRODUCING HEAVY RAINS AND SOME
STORMS MAY BE CAPABLE OF SMALL HAIL AND GUSTY WINDS. OTHERWISE
EXPECT MOSTLY WEST WINDS WITH THE LAKE BREEZE TO THE EAST
POTENTIALLY SWITCHING WINDS TO THE SOUTH/SOUTHEAST LATER THIS
AFTERNOON.
PREV DISCUSSION
(ISSUED 920 AM CDT TUE JUL 7 2020)
UPDATE...
NO MAJOR CHANGES TO THE FORECAST WITH ISOLATED TO SCATTERED
THUNDERSTORMS EXPECTED ACROSS SOUTHERN WISCONSIN WITH THE BEST
CHANCES ALONG THE LAKE WHERE THE LAKE BREEZE SHOULD PROVIDE ENOUGH
LIFT FOR A FEW STORMS.
MARINE...
LIGHT SOUTH TO WEST WINDS EXPECTED TODAY WITH SCATTERED STORMS
POSSIBLE DURING THE AFTERNOON, PRIMARILY ALONG THE EDGES OF THE
LAKE. QUIET CONDITIONS THEN MOVE IN FOR WEDNESDAY WITH HIGH
PRESSURE OVER LAKE MICHIGAN AND PRIMARILY LIGHT SOUTHERLY WINDS
EXPECTED. WINDS WILL BE A BIT MORE BREEZY FROM THE SOUTH OVER THE
LAKE INTO THURSDAY.
PREV DISCUSSION... (ISSUED 630 AM CDT TUE JUL 7 2020)
UPDATE...
FORECAST DETAILS REMAIN ON TRACK FROM THE PREVIOUS DISCUSSION.
AVIATION(12Z TAFS)...
GENERALLY VFR CIGS AND VIS ARE EXPECTED TODAY. SCATTERED
THUNDERSTORM ACTIVITY IS EXPECTED STARTING IN THE AFTERNOON.
LAKESHORE AND NEAR-LAKESHORE TERMINALS WILL LIKELY SEE THIS
ACTIVITY STARTING FIRST IN THE EARLY AFTERNOON AS THE LAKE BREEZE
MOVES INLAND. THEN, FURTHER INLAND TERMINALS WILL SEE INCREASING
COVERAGE OF SCATTERED STORMS DURING THE MID AFTERNOON. FELT
COVERAGE TODAY, ALTHOUGH SCATTERED, WARRANTED PERIODS OF VCTS FOR
ALL TERMINALS. WHERE THESE STORMS OCCUR, BRIEF DROPS TO LOWER
FLIGHT CATEGORIES CAN BE EXPECTED. THESE STORMS WILL DISSIPATE
LATE IN THE AFTERNOON TO EARLY EVENING.
PREV DISCUSSION... (ISSUED 357 AM CDT TUE JUL 7 2020)
SHORT TERM...
FORECAST TODAY THROUGH TOMORROW...FORECAST CONFIDENCE IS
MODERATE...
AFTER A DRY PERIOD IN THE MORNING, SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY WILL RAMP UP DURING THE AFTERNOON HOURS
AGAIN TODAY. STORMS WILL LIKELY BEGIN FIRST ALONG THE LAKE BREEZE
AS IT BEGINS TO MOVE INLAND DURING THE LATE MORNING AND EARLY
AFTERNOON, THEN INLAND COVERAGE WILL INCREASE AS A WEAK 500MB
SHORTWAVE APPROACHES FROM THE WEST DURING THE REMAINDER OF THE
AFTERNOON. DAYTIME HEATING WILL SUPPORT MUCAPE VALUES RANGING FROM
1500 TO 2500 J/KG PER NAM AND RAP SOUNDINGS BUT EFFECTIVE SHEAR
WILL STAY LESS THAN 20KTS. ANY STORMS THAT DO FORM WILL BE PULSE-
LIKE TO MULTICELLULAR IN NATURE. CAN'T RULE OUT A FEW WIND GUSTS
TO 40 TO 50 MPH AND SOME SMALL HAIL WITH SOME OF THE STRONGER
STORMS TODAY. STORMS WILL THEN BEGIN TO SUBSIDE AS THE SUN SETS
THIS EVENING.
TUESDAY NIGHT INTO WEDNESDAY APPEARS DRY AND SUNNY AS A SURFACE
HIGH PRESSURE BUILDS BACK INTO THE AREA AND WARM 700MB TEMPS ARE
ADVECTED OVER THE GREAT LAKE REGION DURING THE DAYTIME,
EFFECTIVELY CAPPING WOULD BE CONVECTION.
BOTH TUESDAY AND WEDNESDAY WILL BE HOT AND HUMID WITH HIGHS IN THE
LOW 90S. HEAT INDICES BOTH DAYS WILL EASILY APPROACH THE UPPER
90S.
LONG TERM...
WEDNESDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE IS MEDIUM:
THE HIGHEST PRECIP CHANCES THROUGH THE EXTENDED PERIOD REMAIN ON
THURSDAY, WHEN A STRONGER SHORTWAVE COMES THROUGH SOUTHERN
WISCONSIN. LEFT A CHANCE FOR STORMS FOR FRIDAY, AS THE MOIST AND
UNSTABLE AIRMASS LINGERS AHEAD OF ANOTHER WAVE AND A COLD FRONT
VIA THE NAM AND ECMWF. THE GFS BRINGS THE FRONT AND DRIER AIRMASS
INTO THE STATE A BIT QUICKER.
LOWER MOISTURE IS EXPECTED FOR THE WEEKEND BEHIND THE
FRONT/TROUGH. LEFT A CHANCE FOR SHOWERS AND STORMS FOR THIS
PERIOD THOUGH, AS A WAVE OR TWO MAY DROP THROUGH THE NORTHWEST
FLOW. DECENT AGREEMENT THEN AMONG MODELS FOR DRIER WEATHER TO
START THE WORK WEEK UNDER HIGH PRESSURE.
THE HOT AND HUMID CONDITIONS WILL LINGER THURSDAY AND POSSIBLY
INTO AT LEAST THE FIRST PART OF FRIDAY. TEMPERATURES WILL BE A
LITTLE COOLER FOR THE WEEKEND INTO EARLY NEXT WEEK, THOUGH STILL
LIKELY A COUPLE/FEW DEGREES ABOVE NORMAL.
AVIATION(09Z TAF UPDATE)...
WIDESPREAD FOG DOES NOT APPEAR LIKELY EARLY THIS MORNING, BUT THE
OCCASIONAL ROAMING BANK CAN'T BE RULED OUT, ESPECIALLY IN LOW
LYING AREAS. OTHERWISE VFR CONDITIONS WILL CONTINUE THROUGHOUT THE
REST OF THE MORNING. THUNDERSTORM TIMING WILL LIKELY BE NUDGED A
BIT LATER WITH THE UPCOMING 12Z ISSUANCE, BUT NO SWEEPING CHANGES
TO PREVIOUS TAFS ARE ANTICIPATED.
MARINE...
SOUTHERLY WINDS WILL BECOME MORE WESTERLY AS THE DAY PROGRESSES ON
TUESDAY. WINDS WILL STAY FAIRLY LIGHT AND WAVES WILL BE CONFINED
TO A FOOT OR LESS. SOME SCATTERED THUNDERSTORM ACTIVITY IS
POSSIBLE DURING THE AFTERNOON HOURS TODAY AS WELL.
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
UPDATE...ARK
TODAY/TONIGHT AND AVIATION/MARINE...ARK
WEDNESDAY THROUGH MONDAY...DDV
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