Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 271510 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1010 AM CDT MON JUL 27 2015

.UPDATE...

HIGH PRESSURE WILL BRING MOSTLY SUNNY SKIES THROUGH THE DAY TODAY.
MODELS HAVE BACKED OFF STORM CHANCES IN THE WEST FROM 24 HOURS
AGO...WITH MODEL PRECIPITABLE WATER SHOWING THE DEEPER MOISTURE
REMAINING WEST. FORECAST HIGH TEMPS SEEM REASONABLE GIVEN THE
SUNSHINE AND TEMPS ALOFT...THOUGH MAY BE ABLE TO RAISE HIGHS A BIT
GIVEN TEMPS ARE ALREADY AROUND 80.

&&

.AVIATION/18Z TAFS/...

QUIET WEATHER IS EXPECTED THROUGH TUESDAY AFTERNOON AS HIGH
PRESSURE REMAINS OVER THE GREAT LAKES. COULD SEE FOG AGAIN TONIGHT
IN THE WISCONSIN RIVER VALLEY...THOUGH INCREASING CLOUDS AND
WINDS MAY INHIBIT DEVELOPMENT. STORMS ARE THEN LIKELY TUESDAY
EVENING AND OVERNIGHT AS A COLD FRONT PUSHES THROUGH THE AREA.

&&

.PREV DISCUSSION... /ISSUED 330 AM CDT MON JUL 27 2015/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

500 MB RIDGE BUILDS IN WITH SURFACE HIGH PRESSURE CENTERED OVER
THE GREAT LAKES MAKING LITTLE EASTWARD PROGRESS. MAJORITY OF
FORECAST SOUNDINGS SHOW LITTLE TO NO CAPE WITH CAPPING OF VARYING
STRENGTH AND DEPTH AROUND 800 MB AND 600 MB. NAM SOUNDINGS DO SHOW
CAPE BUT PREDICATED ON OVERLY GENEROUS LOWER 70S DEW POINTS. THESE
ARE NOT SUPPORTED BY CURRENT DEW POINTS IN EXPECTED LOWER MICHIGAN
SOURCE REGION. GIVEN CONSENSUS CAPPING AND NO TRIGGER...WITH
BETTER CONVERGENCE WELL WEST AND SOUTH OF AREA...HAVE REMOVED POPS
FOR TODAY AND TONIGHT.

WHILE 925 MB TEMPERATURES RISE A DEGREE OR TWO FROM
SUNDAY...STILL HAVE CONCERNS ABOUT IMPACT OF DEBRIS CLOUDS FROM
CONVECTION TO THE WEST INHIBITING TEMPERATURES TODAY...THOUGH
CLOUD COVER IS EXPECTED TO BE THINNER AND LESS EXTENSIVE THAN
YESTERDAY...ESPECIALLY IN THE NORTHWEST FORECAST AREA WHERE
WARMEST TEMPS ARE EXPECTED. EAST SOUTHEAST WINDS WILL KEEP
EASTERN AREAS COOLER THAN FARTHER INLAND.

LEAD SHORT WAVE AND FOCUSED WARM AIR ADVECTION WITH LOW LEVEL JET
AHEAD OF CLOSED LOW APPROACHING THE NRN PLAINS WILL REMAIN WEST OF
STATE THROUGH 12Z TUESDAY. GENERALLY CLEAR SKIES AND LIGHT WINDS
TONIGHT SO EXPECT ANOTHER ROUND OF FOG IN THE WISCONSIN RIVER
VALLEY AND PATCHY FOG ELSEWHERE.

SHORT TERM...TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST
CONFIDENCE IS MEDIUM.

MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THE COLD
FRONTAL PASSAGE ACROSS THE AREA LATER TUESDAY NIGHT...EXITING THE
FAR EAST WEDNESDAY MORNING. NAM/GFS SHOW A LEAD 500 MB VORTICITY
MAXIMUM MOVING INTO THE AREA AROUND 00Z WEDNESDAY...WITH THE ECMWF
SHOWING A WEAKER VERSION OF IT. STEADY SOUTHWEST WINDS AT 850 MB
POINTS INTO THE AREA LATER TUESDAY INTO TUESDAY NIGHT...THOUGH
WARM AIR ADVECTION IS FAIRLY BENIGN.

MODIFIED AREA FORECAST SOUNDINGS FROM NAM/GFS SHOWING MEAN LAYER
CAPES OF 1000 TO 1500 J/KG LATER TUESDAY INTO TUESDAY NIGHT...WITH
WEAK DEEP LAYER SHEAR. PRECIPITABLE WATER VALUES ARE QUITE
HIGH...IN THE 2.00 TO 2.25 INCH RANGE...WHICH IS IN THE 99TH
PERCENTILE FROM CLIMATOLOGY.

SPC HAS AREA IN A MARGINAL SEVERE RISK FOR LATER TUESDAY INTO
TUESDAY NIGHT. GIVEN THE ENVIRONMENTAL PARAMETERS...THINK MAIN
ISSUE WILL BE HEAVY RAINFALL. THERE MAY BE SOME HAIL/WIND GIVEN
THE EXPECTED MEAN LAYER CAPES...THOUGH BEST SHOT AT SEVERE WEATHER
SHOULD BE TO THE WEST OF THE AREA.

WENT WITH INCREASING POPS WEST TO EAST TUESDAY...WITH HIGHEST POPS
WEST TO EAST TUESDAY NIGHT...EXITING THE FAR EAST WEDNESDAY
MORNING. COULD GO WITH HIGHER POPS IN LATER FORECASTS IF MODELS
REMAIN CONSISTENT WITH THE FRONTAL TIMING.

CONTINUED TO GO WITH UPPER 80S FOR HIGHS TUESDAY...WITH HEAT INDEX
VALUES IN THE LOWER TO MID 90S. THESE TEMPERATURES MAY BE HIGH IF
HIGH CLOUDS FROM UPSTREAM CONVECTION MOVE INTO THE AREA LATER ON
TUESDAY...SO THERE IS SOME UNCERTAINTY HERE. LAKE BREEZE SHOULD
KEEP LAKESHORE AREAS SOMEWHAT COOLER.

GUSTY WEST WINDS ARE THEN EXPECTED LATER TUESDAY NIGHT INTO
WEDNESDAY...WITH A FAIRLY TIGHT PRESSURE GRADIENT OVER THE REGION
BEHIND THE FRONT. LESS HUMID CONDITIONS ARE EXPECTED...WITH
TEMPERATURES NEAR SEASONAL NORMALS.

LONG TERM...THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS
MEDIUM.

GFS/ECMWF SHOWING HIGH PRESSURE SOUTH OF THE REGION KEEPING THE
QUIET WEATHER ACROSS THE REGION THURSDAY INTO THURSDAY
NIGHT...WITH WEST NORTHWEST FLOW AT 500 MB. TEMPERATURES WILL
REMAIN NEAR SEASONAL NORMALS.

GFS SHOWING QPF WITH PASSING TROUGH OF LOW PRESSURE THURSDAY
NIGHT...WITH GFS/ECMWF SHOWING ANOTHER SURFACE TROUGH FOR LATER
FRIDAY. NOT MUCH SUPPORT ALOFT SEEN ON THESE MODELS. ADDED LOW
POPS FOR FRIDAY...GIVEN DECENT MEAN LAYER CAPES ON MODIFIED GFS
FORECAST SOUNDINGS.

SOME VARIATION WITH TIMING AND PLACEMENT OF FEATURES WITH SYSTEM
MOVING INTO THE REGION FOR SATURDAY INTO SUNDAY. FOR NOW...USED
CONSENSUS BLEND OF MODELS FOR POPS AND TEMPERATURES.

AVIATION/12Z TAFS/...

VFR CONDITIONS EXPECTED THROUGH THE DAY INTO THE EVENING AS HIGH
PRESSURE PREVAILS OVER THE REGION. HIGH LEVEL DEBRIS CLOUDS FROM
CONVECTION TO THE WEST WILL LIMIT HEATING AND INSTABILITY SOMEWHAT
AND EAST SOUTHEASTERLY WINDS KEEPING EASTERN AREAS COOLER. WITH NO
APPARENT FORCING FOR SHOWERS AND STORMS HAVE REMOVED LOW CHANCES
FOR PRECIPITATION FOR TODAY AND TONIGHT...WITH NEXT BEST CHANCE
COMING TUESDAY/TUESDAY NIGHT WITH PASSAGE OF A COLD FRONT. WILL
SEE FOG IN THE WISCONSIN RIVER VALLEY AGAIN TONIGHT WITH A FEW
PATCHES ELSEWHERE. WITH CHANCES FOR WIDESPREAD FOG IN THE
PROBABILITY FORECASTS VERY LOW WILL LEAVE OUT OF TAFS.

&&

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

$$

UPDATE...DDV
TODAY/TONIGHT AND AVIATION...REM
TUESDAY THROUGH SUNDAY...WOOD


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