Area Forecast Discussion
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000
FXUS63 KLOT 281943
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
243 PM CDT MON JUL 28 2014

.DISCUSSION...
251 AM CDT

SYNOPSIS...TODAY WILL BE A BEAUTIFUL DRY DAY WITH WELL BELOW NORMAL
TEMPS. THE BELOW NORMAL TEMPS CONTINUE THROUGH THE FORECAST PERIOD.
WE STAY IN A PATTERN THAT HAS MULTIPLE WAVES OF UPPER LEVEL ENERGY
ROTATING THROUGH THE REGION. AS SUCH DIURNAL SHOWERS AND
THUNDERSTORMS ARE EXPECTED FROM TUESDAY THROUGH SATURDAY.

TODAY AND TONIGHT...
THE PATTERN ALOFT WILL NOT CHANGE MUCH OVER THE NEXT WEEK WITH A
LARGE LOW/TROUGH TO OUR EAST AND A RIDGE TO OUR WEST.  THE SURFACE
LOW IS OVER NEW ENGLAND WHILE A HIGH IS BUILDING DOWN THE PLAINS.

WE ARE LOOKING AT A DRY AND COOLER THAN NORMAL DAY WITH HIGHS IN THE
LOW 70S. TEMPERATURES WILL BE COOLEST ALONG THE LAKESHORE DUE TO
STRONG NORTH WINDS. WAVES ALONG THE NORTHWEST INDIANA SHORE ARE VERY
HIGH AT 11 FT AT THIS TIME AND STILL EXPECTING DANGEROUS SWIMMING
CONDITIONS AT ALL OF THE BEACHES.  RIP CURRENTS ARE EXPECTED.

WE WILL SEE GUSTS UP TO 35 MPH AGAIN EARLY TODAY WITH WINDS
DIMINISHING IN THE AFTERNOON AS THE PRESSURE GRADIENT WEAKENS
OVERHEAD. CLOUDS CLEAR TONIGHT AND EXPECTING TEMPERATURES TO FALL
INTO THE 50S...WITH LOWS AROUND 60 DOWNTOWN.

TUESDAY THROUGH THURSDAY...
THE SURFACE LOW SHIFTS NORTH INTO QUEBEC WHILE THE PLAINS HIGH
SLOWLY SPREADS OVER THE MIDWEST WEDNESDAY NIGHT.  THE MAIN THEME FOR
THE REST OF THE WEEK WILL BE WEAK VORTICITY STREAMERS ROTATING
AROUND THE UPPER LEVEL LOW.  THESE STREAMERS MAY PROVIDE ENOUGH
FORCING FOR ISOLATED TO SCATTERED AFTERNOON THUNDERSTORM
DEVELOPMENT. CONFIDENCE IS MEDIUM-LOW IN COVERAGE AND TIMING SO HAVE
LOW END CHANCES OF THUNDERSTORMS EACH AFTERNOON. GIVEN THE WEAK
FORCING AND INSTABILITY...NOT EXPECTING SEVERE WEATHER AND THERE
SHOULD BE PLENTY OF DRY HOURS.

LAKE BREEZES ARE EXPECTED EACH DAY...WITH HIGHS ALONG THE LAKESHORE
IN THE MID 70S. HIGHS AWAY FROM THE LAKE WILL BE IN THE UPPER 70S TO
AROUND 80. OVERNIGHT LOWS WILL BE IN THE UPPER 50S TO AROUND
60...AND IN THE LOW 60S DOWNTOWN.

FRIDAY THROUGH SUNDAY...
A LOBE OF UPPER LEVEL ENERGY SWINGS THROUGH THE REGION FRIDAY WHICH
WILL BRING US OUR BEST CHANCE FOR SHOWERS AND STORMS.  AT THIS POINT
INSTABILITY LOOKS WEAK WITH 1000 J/KG OF CAPE OR LESS AND SHEAR DOES
NOT LOOK FAVORABLE FOR SEVERE WEATHER.  HAVE ANOTHER LESS IMPRESSIVE
CHANCE OF AFTERNOON STORMS SATURDAY.  TEMPERATURES REMAIN BELOW
NORMAL WITH HIGHS IN THE UPPER 70S AND LOWS AROUND 60.

JEE

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY N-NNE WINDS EASING LATE AFTERNOON THEN DIMINISHING EARLY EVENING.

* LOW CHANCE FOR SOME SCATTERED THUNDERSTORMS TUESDAY AFTERNOON.

MDB

//DISCUSSION...UPDATED 20Z...

LAKE BOUNDARY IS NOW WELL WEST OF MDW AND RIGHT NEAR THE WEST END
OF ORD AT 1935Z. THE BOUNDARY CONTINUES TO WOBBLE BACK AND FORTH
AT ORD WHICH IS LIKELY ACCOUNTING FOR THE ERRATIC WIND SPEEDS.
DIRECTIONAL CHANGE IS MINIMAL AND RANGES FROM ABOUT 360 TO 030
DEGREES. WIND TRENDS LATE THIS AFTERNOON WILL BE A
CHALLENGE...ESPECIALLY DETERMINING WHEN SPEEDS WILL BEGIN TO
DIMINISH. HAVE MADE SOME ADJUSTMENTS TO TRY AND DETAIL THE CHANGES
WITH THE 20Z TAF UPDATE. IF THE BOUNDARY REMAINS IN CLOSE
PROXIMITY TO ORD THEN SPEEDS COULD DROP OFF MORE QUICKLY AS THE
BOUNDARY DISSIPATES AND MIXING WINDS DOWN INTO THE EVENING. IF IT
STAYS WEST THEN SPEEDS WOULD STAY UP A BIT LONGER.

FROM 18Z...

STRONG PRESSURE GRADIENT CONTINUES ACROSS THE TERMINALS WITH GUSTS
IN THE 20-25 KT RANGE ACROSS IL AND PUSHING 30 KT AT TIMES NEAR
THE LAKE MICHIGAN SHORE OF NW INDIANA. THE DIRECTION CONTINUES TO
FLUCTUATE BETWEEN N AND NNE AND WILL LIKELY CONTINUE TO DO SO
THROUGH AFTERNOON. THE PRESSURE GRADIENT SLACKENS LATE THIS
AFTERNOON SO SPEEDS SHOULD EASE BUT THIS MAY TAKE SOME TIME INTO
THE EVENING. WIND DIRECTION MAY BECOME VARIABLE THIS EVENING WITH
A LIGHT NORTHWEST DIRECTION EXPECTED OVERNIGHT. A STEADIER
NORTHWEST WIND IS EXPECTED TUESDAY. A LAKE BREEZE MAY TURN WINDS
NORTHEAST AT GYY TUESDAY AFTERNOON BUT WILL KEEP THE LAKE BREEZE
EAST OF ORD/MDW FOR NOW.

A SERIES OF UPPER WAVES WILL CROSS THE AREA THE NEXT FEW DAYS WITH
ONE WAVE PASSING OVERNIGHT POTENTIALLY BRINGING SOME MID CLOUDS.
WEAK ASCENT WILL BE IN PLACE TUESDAY WHICH MAY TRIGGER SOME ISOLD-
SCT SHRA/TSRA DURING THE AFTERNOON. THREAT IS TOO LOW TO MENTION
IN THE TAF AT THIS TIME. OTHERWISE SHOULD SEE AN INCREASE IN
DIURNAL CLOUDS.

MDB

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN WIND TRENDS THROUGH MID AFTERNOON. MEDIUM
  CONFIDENCE IN NNE WINDS BECOMING NE LATE THIS AFTERNOON WITH
  SPEEDS EASING INTO EARLY EVENING.

* HIGH CONFIDENCE THAT TSRA CHANCES ARE LOW TUESDAY AFTERNOON AND
  COVERAGE WOULD BE ISOLATED TO SCATTERED.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

TUESDAY NIGHT...SLIGHT CHANCE OF AN EVE STORM.
WEDNESDAY-SATURDAY...MAINLY VFR. SLIGHT CHANCE OF AFTERNOON TSRA.
SUNDAY...VFR.

MTF

&&

.MARINE...
124 PM CDT

NORTHERLY WINDS CONTINUE UP AROUND 25 KT ACROSS THE SOUTHERN HALF OF
THE LAKE EARLY THIS AFTERNOON...AND THIS IS CONTINUING TO RESULT IN
BUOY OBSERVATIONS OF 8 TO 10 FOOT WAVES. THESE WINDS WILL GRADUALLY
EASE LATE THIS AFTERNOON AND EVENING...AND EVEN BECOME WESTERLY
TONIGHT AS THE GRADIENT WEAKENS. HOWEVER...WAVE HEIGHTS WILL BE SLOW
TO SUBSIDE...WITH 4+ FOOTERS EXPECTED ACROSS SOUTHERN LAKE MICHIGAN
THROUGH MUCH OF TONIGHT. NO CHANGES ARE PLANNED TO THE CURRENT
ENDING TIMES OF THE SMALL CRAFT ADVISORIES.

FOLLOWING TODAY`S WIND AND WAVE EVENT...IT APPEARS THE WEATHER WILL
BE SOMEWHAT QUIET ACROSS THE LAKE DURING THE WEEK. AN UPPER LEVEL
LOW OVER QUEBEC WILL CONTINUE TO LEAD TO A WEST NORTHWESTERLY FLOW
PATTERN...ALBEIT LIGHT...ACROSS THE LAKE THROUGH MUCH OF THE PERIOD
AS A COUPLE OF WEAK COLD FRONTAL BOUNDARIES DROP SOUTHWARD OVER THE
LAKE.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ014 UNTIL 4 AM TUESDAY.

     BEACH HAZARDS STATEMENT...ILZ006 UNTIL 10 PM MONDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM TUESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM MONDAY.

     SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 4 AM
     TUESDAY.

&&

$$

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