Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 281759
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1259 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 18Z...

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

* LOW CHANCE FOR SOME SCATTERED THUNDERSTORMS TUESDAY AFTERNOON.

MDB

//DISCUSSION...UPDATED 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 18Z...

* HIGH CONFIDENCE IN WIND TRENDS THROUGH MID AFTERNOON. MEDIUM
  CONFIDENCE IN NNE WINDS LATE THIS AFTERNOON WITH SPEEDS EASING.
  WINDS MAY BECOME VARIABLE UNDER 10 KT THIS 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...
215 AM CDT

IMPRESSIVE WINDS AND WAVES FOR JULY ARE OCCURRING EARLY THIS
MORNING ACROSS THE SOUTHERN PART OF THE LAKE WITH 2 AM
OBSERVATIONS INDICATING THE SOUTH BUOY AT 8.6 FT AND MICHIGAN CITY
AT 11.1 FT. NORTHERLY WINDS OF 30 KT WITH OCCASIONAL GALES WILL
EVER SO SLOWLY EASE THIS MORNING ACROSS THE SOUTH. THE GRADIENT
BETWEEN A DEPARTING LOW IN THE NORTHEAST U.S. AND A HIGH OVER THE
NORTHERN PLAINS WILL EASE THIS AFTERNOON AND MORE SO TONIGHT.
WAVES WILL BE SLOW TO SUBSIDE ALONG THE INDIANA SHORE BUT ARE
EXPECTED TO DROP BELOW SMALL CRAFT ADVISORY CRITERIA BY DAYBREAK
TUESDAY.

A STRONG UPPER TROUGH ACROSS EASTERN CANADA WILL MOVE LITTLE THROUGH
MIDWEEK. AS IS OFTEN THE CASE...WEAKER SECONDARY SURFACE COLD FRONTS
WILL MOVE ACROSS THE GREAT LAKES...WITH ONE SUCH FRONT EXPECTED ON
TUESDAY AFTERNOON AND NIGHT ACROSS NORTHERN LAKE MICHIGAN. THIS WILL
HAVE OVERALL LITTLE INFLUENCE HOWEVER. THE PRESSURE GRADIENT WILL
REMAIN LIGHT ACROSS THE LAKE FOR MUCH OF THE WEDNESDAY THROUGH
SATURDAY TIME PERIOD WITH AN AFTERNOON LAKE BREEZE ON THE
ILLINOIS AND INDIANA SHORES WEDNESDAY AND THURSDAY...AND OVERALL
SYNOPTIC ONSHORE FLOW ON FRIDAY AND SATURDAY.

MTF

&&

.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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