Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 012030
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 PM CDT WED JUL 1 2015

.SHORT TERM...
327 PM CDT

THROUGH SATURDAY...

GENERALLY QUIET CONDITIONS EXPECTED THROUGH THE PERIOD AS
STEERING FLOW WILL TEND TO KEEP BEST FORCING TO THE SOUTH OF THE
CWA. IN THE NEAR TERM...HAVE MAINTAINED A DRY FORECAST FOR MOST
AREAS THIS EVENING THROUGH MIDNIGHT OUTSIDE OF LOW CHANCE POPS FOR
THE FAR SOUTHERN CWA OWING TO POTENTIAL SLIGHT EXPANSION OF
SHOWERS CURRENTLY TO THE WEST/SOUTHWEST. ALSO MONITORING SMALL
AREA OF PRECIP DROPPING SOUTHEAST THROUGH EASTERN IOWA.
EXTRAPOLATING THIS ALONG SOUTHEASTWARD MEAN FLOW ALOFT...IT WOULD
CLIP AREAS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...AT THIS
TIME...LITTLE PRECIP IS ACTUALLY MAKING IT TO THE GROUND. WITH
RATHER DRY CONDITIONS IN PLACE OVER THE CWA...WOULD EXPECT FURTHER
EROSION OF THIS PRECIP WITH EVEN LESS OF IT MAKING IT TO THE
GROUND. SO...IF ANYTHING WERE TO OCCUR...IT WOULD BE A BRIEF
SPRINKLE. CLOUD COVER TONIGHT MAY BE A LITTLE CHALLENGING...BUT
WENT MORE AGGRESSIVE WITH CLOUD COVER IN THE NEAR TERM AND LATER
TONIGHT. MID/HIGH CLOUDS APPROACHING WILL PROVIDE CONTINUED CLOUDY
CONDITIONS THIS EVENING...AND THEN LOW STRATUS OVER THE SOUTHERN
HALF OF THE LAKE AND SOUTHWEST MICHIGAN LOOKS TO WORK ITS WAY BACK
SOUTHWEST MORE TOWARDS EARLY THURSDAY MORNING.

A CONTINUED SOUTHERLY TREND WITH APPROACHING SYSTEMS THURSDAY
THROUGH SATURDAY HAS OCCURRED...AND HAVE LOWERED POPS THROUGH THE
PERIOD WITH DRY CONDITIONS EXPECTED FOR THE CWA. ALTHOUGH TEMPS
WILL CONTINUE TO BE BELOW NORMAL THROUGH THE END OF THE
WORK...TEMPS WILL BEGIN TO REBOUND BY SATURDAY WITH HIGHS AROUND
80 FORECAST. HOWEVER...PERSISTENT ONSHORE FLOW WILL KEEP TEMPS
LOWER NEAR THE LAKE.

RODRIGUEZ

&&

.LONG TERM...
327 PM CDT

SATURDAY NIGHT THROUGH WEDNESDAY...

SATURDAY EVENING IS LOOKING LIKE IT WILL REMAIN DRY FOR 4TH OF
JULY FIREWORKS IN THE ABSENCE OF ANY REAL FORCING OR INSTABILITY.
THIS PATTERN LOOKS TO CONTINUE INTO SUNDAY AND SUNDAY
EVENING...THOUGH A FEW STRAY SHOWERS/POP-UP TSTORMS CANNOT BE
RULED OUT ACROSS THE SOUTHERN PORTION OF THE CWA. ATTENTION THEN
TURNS TO MONDAY AS MODEL GUIDENCE CONTINUES TO ADVERTISE THE
SOUTHWARD MOVEMENT OF A LOW AMPLITUDE TROUGH WELL TO THE NORTHWEST
WITH A CORRESPONDING COLD FRONT. WAA LOOKS TO RAMP UP DURING THE
DAY ON MONDAY...THOUGH MOST OF THE DAY WILL LIKELY REMAIN DRY AS
THE BEST FORCING STAYS NORTH OF THE AREA. MODEL GUIDANCE HAS
STARTED TO AGREE THAT THE COLD FRONT WILL PASS THROUGH THE CWA
LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING. HOWEVER...RUN-TO-RUN
INCONSISTENCY HAS LED TO LOW CONFIDENCE ON THE EXACT TIMING OF THE
FROPA...AS WELL AS THE STRENGTH OR COVERAGE OF ANY ASSOCIATED
CONVECTION. AREA-WIDE SLIGHT POPS MAY HAVE TO BE ADJUSTED IN
FUTURE FORECASTS AS MODEL GUIDANCE CONSISTENCY INCREASES. THERE
ARE ALSO QUESTIONS ON WHETHER THE FRONT WILL PASS RIGHT ALONG OR
STALL INTO THE TUESDAY AND WEDNESDAY TIMEFRAME...WHICH WOULD HAVE
IMPLICATIONS ON AREAWIDE POPS...CLOUD COVER...AND TEMPS.

BATZEK/BORCHARDT/NIXON

&&

.AVIATION...

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

* LAKE BREEZE/NORTHEAST WINDS APPROACHING 10 TO 12KT THIS
  AFTERNOON.
* MVFR CIGS POSSIBLE BRIEFLY THURSDAY MORNING.

ED F

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

CLEARING LINE APPROACHING FROM THE NORTH THIS AFTERNOON WILL
STRIP AWAY MVFR CIGS AND INCREASE WINDS BY AROUND 19Z. BRIEF WIND
OBS SHOWING NORTH SHOULD QUICKLY CHANGE BACK TO NORTHEAST UNDER
THIS WEAK HIGH PRESSURE REGIME. WHILE VFR CONDITIONS ARE
FORECASTED FOR MOST OF THE PERIOD...THERE IS A CHANCE FOR MVFR
CIGS AGAIN TOMORROW MORNING. NORTHEAST WINDS OFF OF LAKE MICHIGAN
WILL STREAM IN ADDITIONAL MOISTURE...LEADING TO SCT TO BKN CLOUDS
AT 2KFT FROM 11-14Z. DAYTIME HEATING AND ADVANCING HIGH PRESSURE
SHOULD LIFT THOSE TO JUST FAIR WEATHER CUMULUS BY MID MORNING.

WINDS REMAIN FROM THE NORTHEAST THURSDAY AND WILL APPROACH THE
10KT MARK BY 18Z. HIGHER CONFIDENCE IN THE WINDS THURSDAY AS THIS
IS A PRESSURE DRIVEN WIND WITH LITTLE LAKE INFLUENCE.

MM

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

* MEDIUM CONFIDENCE IN TIMING OF NORTHEAST WINDS...HIGH IN WIND
  SPEED.
* LOW CONFIDENCE IN MVFR DEVELOPMENT THURSDAY MORNING.

ED F

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

THURSDAY NIGHT THROUGH SATURDAY...DRY AND VFR. NE WINDS.
SUNDAY...DRY AND VFR. SE WINDS.
MONDAY THROUGH TUESDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
314 AM CDT

NORTH WINDS HAVE PICKED UP INTO THE 15 TO 25 KT RANGE AT TIMES IN
BETWEEN AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES AND A
RIDGE OVER ONTARIO AND THE UPPER MIDWEST. THE HIGH WILL BUILD SOUTH
OVER LAKE MICHIGAN WITH WINDS GRADUALLY ABATING FROM THE NORTH
TODAY THROUGH THURSDAY. THE HIGH SHOULD PROVIDE QUIET WEATHER AND
RELATIVELY LIGHT WINDS FRIDAY THROUGH THE WEEKEND. SOUTHWEST WINDS
LOOK TO FRESHEN UP AGAIN MONDAY AHEAD OF AN APPROACHING COLD
FRONT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...BEACH HAZARDS STATEMENT...INZ002 UNTIL 8 PM WEDNESDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN
UNTIL 8 PM WEDNESDAY.

&&

$$

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