Area Forecast Discussion
Issued by NWS Chicago, IL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KLOT 232322
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
622 PM CDT TUE SEP 23 2014

.DISCUSSION...
315 PM CDT

RUN OF PLEASANT EARLY FALL WEATHER CONTINUES AND STILL LOOKS TO
CONTINUE THROUGH THE WEEKEND. WATER VAPOR SHOWS AN UPPER LOW SLOWLY
SPINNING OVER SOUTH CAROLINA CUTOFF FROM A MAIN LONGWAVE TROUGH OVER
EASTERN CANADA. BROAD UPPER RIDGING IS FOUND ACROSS CENTRAL CANADA
INTERRUPTED BY A CUTOFF UPPER LOW SPINNING NORTHEAST OVER THE
NORTHERN PLAINS. A BIG UPPER LOW IS SPINNING OFF THE PACIFIC
NORTHWEST/BRITISH COLUMBIA COAST. AT THE SURFACE...HIGH PRESSURE
REMAINS SPREAD ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY WITH A
SECONDARY HIGH TO ITS NORTH INTO EASTERN ONTARIO AND JAMES BAY. A
TROUGH EXTENDS FROM THE CANADIAN PRAIRIES TO THE SOUTHERN HIGH
PLAINS.

TONIGHT THROUGH THURSDAY...THE CUTOFF UPPER LOW OVER THE NORTHERN
PLAINS WILL CONTINUE NORTHEASTWARD AND SHOULD LOSE FOCUS WITH TIME.
A BROAD AREA OF RAIN ACROSS WESTERN IOWA WILL LIFT NORTHEAST AS WELL
AND REMAIN WEST OF THE AREA TONIGHT. SOME CIRRUS STREAKS FROM THE
EXTENSIVE CLOUD SHIELD TO THE WEST MAY CROSS THE AREA THROUGH THE
OVERNIGHT. WITH A LIGHT BUT STEADY SOUTH TO SOUTHEAST WIND AND A
WARMER START TO THE NIGHT AM EXPECTING LOWS TO GENERALLY BE SEVERAL
DEGREES WARMER THAN LAST NIGHT FOR AREAS OUTSIDE THE IMMEDIATE METRO
AREAS...MAINLY UPPER 40S...THOUGH MID AND POSSIBLY A FEW LOWER 40S
MAY BE FOUND ACROSS THE SOUTHEAST CWA WHERE WINDS ARE MORE LIKELY TO
GO CALM. THE UPPER TROUGH WILL CONTINUE TO WEAKEN AS IT MOVES ACROSS
LAKE SUPERIOR BUT A RIBBON OF MID/HIGH LEVEL MOISTURE MAY LINGER
ENOUGH TO BRING A MORE EXTENSIVE ROUND OF CIRRUS LATER WEDNESDAY AND
ESPECIALLY WEDNESDAY NIGHT. LATEST WRF BASED GUIDANCE IS MORE
PRONOUNCED WITH THE MOISTURE WITH SOME EVENING BRINGING SOME LIGHT
PRECIP. WILL CONTINUE WITH A DRY FORECAST BUT INCREASE CLOUD COVER A
BIT THROUGH THURSDAY. HIGHS WILL BE IN THE 70S...WITH LAKEFRONT
AREAS SEEING AFTERNOON COOLING TO AROUND 70.

FRIDAY THROUGH TUESDAY... THE BIG UPPER LOW OFF THE WEST COAST
WILL MAKE SLOW PROGRESS EASTWARD HELPING TO BUILD ANOTHER
EXPANSIVE RIDGE ACROSS THE U.S. INTO FRIDAY. THIS RIDGE WILL
REMAIN IN PLACE THROUGH THE WEEKEND WITH SURFACE HIGH PRESSURE
BUILDING ACROSS THE LOWER GREAT LAKES ONCE AGAIN. ENERGY LOOKS TO
OVER TOP THE RIDGE ACROSS SOUTHERN CANADA LATER IN THE WEEKEND
HELPING A TROUGH TO DEVELOP OVER THE NORTHEAST AND POSSIBLY
BRINGING A WEAK FRONT INTO THE AREA TOWARD MONDAY. THE RIDGE
BREAKS DOWN INTO TUESDAY WITH TROUGHING MOVING INTO THE HIGH
PLAINS WITH A CONTINUED SIGNAL OF A TROUGH DEVELOPING OVER THE
GULF COAST AND SENDING MOISTURE NORTHWARD TOWARD THE REGION MID
NEXT WEEK. WILL KEEP THE FORECAST DRY THROUGH MONDAY BUT CARRY LOW
POPS TUESDAY WITH HIGHS IN THE 70S WITH CONTINUED LAKE COOLING
EACH DAY.

MDB

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* LAKE BREEZE PROBABLE WED AFTERNOON ORD AND POSSIBLE FOR MDW

IZZI

//DISCUSSION...UPDATED 00Z...

VFR CONDITIONS WITH CALM TO LIGHT SOUTHEAST WINDS THROUGH WED
MORNING. LAKE BREEZE LIKELY TO FORM WED AFTERNOON AND PROBABLY
PASSING THROUGH ORD LATE IN THE AFTERNOON AND POTENTIALLY
AFFECTING MDW LATE IN THE DAY AS WELL.

IZZI

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* MEDIUM CONFIDENCE IN LAKE BREEZE WED PM AT ORD AND LOW
  CONFIDENCE FOR MDW
* HIGH CONFIDENCE IN ALL OTHER ELEMENTS

IZZI

//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...

THURSDAY THROUGH MONDAY...VFR.

IZZI

&&

.MARINE...
208 PM CDT

HIGH PRESSURE WILL DOMINATE THE REGION THROUGH THE REMAINDER OF THE
WEEK INTO THE WEEKEND ALLOWING GENERALLY LIGHT SOUTHERLY FLOW. WINDS
WILL BE LIGHT ENOUGH ESPECIALLY OVER THE SOUTH END OF LAKE MICHIGAN
TO ALLOW LAKE AND LAND BREEZES TO DEVELOP RESULTING IN SOME
VARIABILITY IN THE WIND DIRECTION...PARTICULARLY CLOSER TO THE
SHORE.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.