Area Forecast Discussion
Issued by NWS Chicago, IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 042035
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
235 PM CST THU FEB 4 2016

.SHORT TERM...
234 PM CST

THROUGH SATURDAY...

ANOTHER WEAK CLIPPER SYSTEM IS CURRENTLY SHIFTING EASTWARD ACROSS
THE UPPER MIDWEST AND UPPER GREAT LAKES REGION. THIS SYSTEM WILL
DRIVE ANOTHER FRONTAL BOUNDARY ACROSS THE AREA THROUGH THIS EVENING.
AHEAD OF THIS BOUNDARY...THERE COULD BE A FEW LIGHT FLURRIES THIS
EVENING...PARTICULARLY ACROSS NORTH CENTRAL ILLINOIS AS SOME MODEST
ISENTROPIC UPGLIDE SETS UP. HOWEVER...NO ACCUMULATION IS EXPECTED.

A SURFACE RIDGE OF HIGH PRESSURE WILL BUILD OVER THE AREA ON FRIDAY.
SO...IT WILL BE DRY DURING THE DAY...BUT CLOUDY AS SOME HIGHER
CLOUDS MOVE OVER THE REGION. TEMPERATURES ONCE AGAIN LOOK TO TOP OUT
NEAR 30 NORTH AND INTO THE LOW TO MID 30S SOUTH. WARMER CONDITIONS
ARE EXPECTED ON SATURDAY AS SOUTHWESTERLY FLOW SETS UP IN THE WAKE
OF THE DEPARTING SURFACE RIDGE AXIS. THIS SHOULD ALLOW TEMPERATURES
TO GET INTO THE LOW 40S SOUTH AND THE MID TO UPPER 30S NORTH.

KJB

&&

.LONG TERM...
334 AM CST

SUNDAY THROUGH THURSDAY...

THE UP AND DOWN PARADE WILL TAKE A TURN SUNDAY INTO THE COMING
WEEK AS A MASSIVE RIDGE BUILDS ACROSS THE WEST. DOWNSTREAM
TROUGHING WILL LEAD TO AT LEAST A COUPLE DAY INTRUSION OF CANADIAN
AIR. SEVERAL PERIODS OF LIGHT SNOW APPEAR ON TAP FOR
SUNDAY...MONDAY...AND POSSIBLY TUESDAY. IT WILL GENERALLY BE ON
THE CLOUDIER SIDE AND BREEZY AS WELL INITIALLY...MAKING IT FEEL A
BIT MORE UNCOMFORTABLE. THE GFS IS MORE AGGRESSIVE WITH THE
COOLING...SNOW SHOWER COVERAGE...AND WIND SPEEDS THAN THE ECMWF AT
THIS POINT...BUT THE THEME IS FOR COLDER CONDITIONS WITH POSSIBLE
LIGHT SNOW AS ENSEMBLES INDICATE DECENT CONFIDENCE IN THIS DEEP
EASTERN CONUS TROUGH EVOLUTION DESPITE DISAGREEING SOME ON ITS
STRENGTH AND BREAKDOWN.

KMD

&&

.AVIATION...
FOR THE 18Z TAFS...

A WEAK STORM SYSTEM OVER THE UPPER MIDWEST WILL BE THE MAIN WEATHER-
MAKER ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA THROUGH THE 18Z
TAF PERIOD.  A TRAILING WARM FRONT CURRENTLY OVER EASTERN IOWA WILL
SPREAD MID-LEVEL CLOUDS INTO THE AREA LATE THIS AFTERNOON AND
EVENING.  BASED ON SATELLITE TIMING TOOLS, VFR CEILINGS WILL ARRIVE
AT KRFD BY 21Z...THEN FURTHER EAST TO KORD AND KMDW BY 23Z.  WINDS
WILL INITIALLY BE FROM THE W/NW AT 10KT THEN WILL BACK TO THE S/SW
TOWARD EVENING.  WINDS WILL THEN VEER BACK TO THE W/NW LATE TONIGHT
INTO FRIDAY MORNING AS A COLD FRONT PASSES THROUGH THE REGION.
LATEST SATELLITE IMAGERY AND UPSTREAM OBS ARE SHOWING A NARROW BAND
OF MVFR CEILINGS IMMEDIATELY ALONG/BEHIND THE COLD FRONT.  BOTH THE
NAM AND RAPID REFRESH SUGGEST THESE LOWER CLOUDS WILL SPREAD ACROSS
THE KLOT TERMINALS LATE TONIGHT.  FORECAST SOUNDINGS ARE SHOWING
MVFR CEILINGS ARRIVING AT KRFD AT 08Z...THEN FURTHER EAST TO KORD
AND KMDW BY 11Z.  THESE CLOUDS WILL THEN CLEAR FROM WEST TO EAST
LATE FRIDAY MORNING INTO FRIDAY AFTERNOON.


BARNES

&&

.MARINE...
232 PM CST

BROAD SURFACE HIGH PRESSURE STRETCHES FROM THE TENNESSEE VALLEY
NORTH THROUGH CENTRAL ONTARIO...RESULTING IN A LIGHT WEST FLOW
ACROSS LAKE MICHIGAN THIS AFTERNOON. SURFACE RIDGE WILL SHIFT EAST
FRIDAY...ALLOWING ANOTHER LOW PRESSURE SYSTEM TO SLIDE EAST ACROSS
THE UPPER MIDWEST TO NORTH OF LAKE SUPERIOR FRIDAY NIGHT INTO
SATURDAY. THIS WILL LIKELY INCREASE THE GRADIENT AND WINDS FROM THE
WEST TO SOUTHWEST...WITH SPEEDS INCREASING TO AROUND 25 TO 30 KT
ACROSS THE NORTHERN HALF OF THE LAKE THROUGH SAT MORNING. FURTHER
SOUTH THE GRADIENT ARRIVES AFTER DAYBREAK SAT WITH SPEEDS BETWEEN 20-
25KT SAT. THEN A WEAK GRADIENT SLIDES BACK ACROSS THE LAKE SATURDAY
NIGHT THROUGH EARLY SUNDAY...BEFORE A MUCH STRONGER LOW PRESSURE
SYSTEM DIVES SOUTHEAST FROM CENTRAL CANADA SUNDAY AFTERNOON. THIS
SYSTEM WILL BRING COOLER AIR TO THE WESTERN GREAT LAKES SUNDAY
EVENING...ALONG WITH WINDS INCREASING FROM THE SOUTHWEST BETWEEN 20-
25KT AND POSSIBLY NEARING 30 KT ACROSS THE NORTHERN HALF OF THE LAKE
BY SUNDAY EVENING THROUGH MONDAY MORNING. THE LOW PRESSURE WILL THEN
SLIDE SOUTHEAST ACROSS CENTRAL WISCONSIN AND SLOW AS IT APPROACHES
CENTRAL LAKE MICHIGAN MONDAY EVENING...ALLOWING THE BRIEF LULL IN
THE GRADIENT THROUGH MONDAY NIGHT...BEFORE INCREASING AND TURNING
NORHT/NORTHWEST HEADING INTO TUESDAY AND NEARING 30KT WITH A FEW
GALES POSSIBLE.

BEACHLER

&&

.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/NWSCHICAGO
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.